Each Consisting of One Share of Common Stock,
One Long-Term Warrant to Purchase 0.25 Shares of Common Stock and

We are offering 4,477,612 units consisting of one share of common stock, par value $0.001 per share, one long-term warrant to purchase 0.25 shares of common stock and one over-allotment warrant to purchase 0.25 shares of common stock (and the shares of common stock issuable from time to time upon exercise of the offered warrants), pursuant to this prospectus supplement and the accompanying prospectus. The purchase price for each unit is $3.35. Each long-term warrant will have an exercise price of $4.00 per share, will be exercisable beginning six months after date of issuance and will expire five years after it becomes exercisable. Each over-allotment warrant will have an exercise price of $3.35 per share, will be exercisable immediately and will expire one year after the date of issuance. Units will not be issued or certificated. The shares of common stock and the warrants are immediately separable and will be issued separately, but will be purchased together in this offering.

Our common stock is presently listed on The NASDAQ Capital Market under the symbol “NWBO”. On August 8, 2013, the closing sale price of our common stock was $3.46 per share.

The warrants are not and will not be listed for trading on The NASDAQ Capital Market or any other exchange.

Investing in our securities involves a high degree of risk. See “Risk Factors” beginning on page S-5 of this prospectus supplement and on page 4 of the accompanying prospectus for a discussion of information that should be considered in connection with an investment in our securities.

(1) Does not include a cash fee of $97,500 payable to Summer Street Research Partners as co-placement agent. For additional information please refer to “Plan of Distribution” beginning on page S-23.

We have engaged Oppenheimer & Co. Inc. as lead placement agent in this offering to use its best efforts to solicit offers to purchase the units in this offering. The placement agent is not purchasing or selling any units pursuant to this prospectus supplement or the accompanying prospectus, nor are we requiring any minimum purchase or sale of any specific number of units.

We expect that delivery of the units being offered pursuant to this prospectus supplement will be made to investors on or about August 14, 2013.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined whether this prospectus supplement or the accompanying prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

On January 7, 2013, we filed with the Securities and Exchange Commission, or SEC, a registration statement on Form S-3 (File No. 333-185898) utilizing a shelf registration process relating to the securities described in this prospectus supplement, which registration statement, as amended, was declared effective on February 5, 2013. Under this shelf registration process, we may, from time to time, sell up to $100.0 million in the aggregate of common stock, preferred stock, warrants, various series of debt securities and/or warrants to purchase any of such securities, either individually or in units.

This prospectus supplement describes the specific terms of an offering of our securities and also adds to and updates information contained in the accompanying prospectus and the documents incorporated by reference into the accompanying prospectus. The second part, the accompanying prospectus, provides more general information. If the information in this prospectus supplement is inconsistent with the accompanying prospectus or any document incorporated by reference therein filed prior to the date of this prospectus supplement, you should rely on the information in this prospectus supplement.

In making your investment decision, you should rely only on the information contained or incorporated by reference in this prospectus supplement and the accompanying prospectus and any relevant free writing prospectus. We have not authorized anyone to provide you with any other information. If you receive any information not authorized by us, you should not rely on it. We are not making an offer to sell the securities in any jurisdiction where the offer or sale is not permitted. You should not assume that the information contained or incorporated by reference in this prospectus supplement or the accompanying prospectus or any relevant free writing prospectus is accurate as of any date other than its respective date.

It is important for you to read and consider all of the information contained in this prospectus supplement and the accompanying prospectus in making your investment decision. We include cross-references in this prospectus supplement and the accompanying prospectus to captions in these materials where you can find additional related discussions. The table of contents in this prospectus supplement provides the pages on which these captions are located. You should read both this prospectus supplement and the accompanying prospectus, together with the additional information described in the sections entitled “Where You Can Find More Information” and “Incorporation of Certain Information by Reference” of this prospectus supplement, before investing in our securities.

We are offering to sell, and seeking offers to buy, our securities only in jurisdictions where offers and sales are permitted. The distribution of this prospectus supplement and the accompanying prospectus and the offering of the securities in certain jurisdictions may be restricted by law. Persons outside the United States who come into possession of this prospectus supplement and the accompanying prospectus must inform themselves about, and observe any restrictions relating to, the offering of the securities and the distribution of this prospectus supplement and the accompanying prospectus outside the United States. This prospectus supplement and the accompanying prospectus do not constitute, and may not be used in connection with, an offer to sell, or a solicitation of an offer to buy, any securities offered by this prospectus supplement and the accompanying prospectus by any person in any jurisdiction in which it is unlawful for such person to make such an offer or solicitation.

Our primary executive offices are located at 4800 Montgomery Lane, Suite 800, Bethesda, MD 20814, and our telephone number is (240) 497-9024. Our website address is http://www.nwbio.com. The information contained on our website is not a part of, and should not be construed as being incorporated by reference into, this prospectus supplement.

Unless the context otherwise requires, “Northwest,” the “company,” “we,” “us,” “our” and similar names refer to Northwest Biotherapeutics, Inc.

The SEC encourages companies to disclose forward-looking information so that investors can better understand a company’s future prospects and make informed investment decisions. This prospectus supplement, the accompanying prospectus and the documents we have filed with the SEC that are incorporated herein and therein by reference contain such “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995.

Words such as “may,” “might,” “should,” “anticipate,” “estimate,” “expect,” “projects,” “intends,” “plans,” “believes” and words and terms of similar substance used in connection with any discussion of future operating or financial performance, identify forward-looking statements. Forward-looking statements represent management’s current judgment regarding future events and are subject to a number of risks and uncertainties that could cause actual results to differ materially from those described in the forward-looking statements. These risks include, but are not limited to:

Please also see the discussion of risks and uncertainties under “Risk Factors” beginning on page S-5 of this prospectus supplement and page 4 of the accompanying prospectus, in our most recent Annual Report on Form 10-K/A, and our Quarterly Report on Form 10-Q for the quarter ended March 31, 2013, as filed with the SEC and which are incorporated herein by reference.

In light of these assumptions, risks and uncertainties, the results and events discussed in the forward-looking statements contained in this prospectus supplement or the accompanying prospectus or in any document incorporated herein or therein by reference might not occur. Investors are cautioned not to place undue reliance on the forward-looking statements, which speak only as of the date of this prospectus supplement or the accompanying prospectus or the date of the document incorporated by reference herein or therein. We are not under any obligation, and we expressly disclaim any obligation, to update or alter any forward-looking statements, whether as a result of new information, future events or otherwise, except as required by law. All subsequent forward-looking statements attributable to us or to any person acting on our behalf are expressly qualified in their entirety by the cautionary statements contained or referred to in this section.

Investing in our common stock involves risk. Before deciding whether to invest in our common stock, you should consider carefully the risks and uncertainties described below. You should also consider the risks, uncertainties and assumptions discussed under the heading “Risk Factors” included in our most recent annual report on Form 10-K/A which is on file with the SEC and is incorporated herein by reference, and which may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the future. There may be other unknown or unpredictable economic, business, competitive, regulatory or other factors that could have material adverse effects on our future results. If any of these risks actually occurs, our business, business prospects, financial condition or results of operations could be seriously harmed. This could cause the trading price of our common stock to decline, resulting in a loss of all or part of your investment. Please also read carefully the section above entitled “Cautionary Note Regarding Forward-Looking Statements.”

We will need to raise substantial funds, on an ongoing basis, for general corporate purposes and operations, including our clinical trials. Such funding may not be available or may not be available on acceptable terms.

We will need substantial additional funding, on an ongoing basis, in order to continue execution of our clinical trials, to move our product candidates towards commercialization, to continue prosecution and maintenance of our large patent portfolio, to continue development and optimization of our manufacturing and distribution arrangements, and for other corporate purposes. Any financing, if available, may include restrictive covenants and provisions that could limit our ability to take certain actions, preference provisions for the investors, and/or discounts, warrants or other incentives. Any financing will involve issuance of equity and/or debt, and such issuances will be dilutive to existing shareholders. There can be no assurance that we will be able to complete any of the financings, or that the terms for such financings will be acceptable. If we are unable to obtain additional funds on a timely basis or on acceptable terms, we may be required to curtail or cease some or all of our operations at any time.

We are likely to continue to incur substantial losses, and may never achieve profitability.

As of March 31, 2013, we had an aggregate accumulated cash deficit, since inception of our company, of $147.0 million, and accumulated non-cash (accounting measures) deficit of $186.5 million, making a combined cash and non-cash accumulated deficit of $333.5 million since our inception. We may never achieve or sustain profitability.

Our independent auditors have indicated in their report on our December 31, 2012 financial statements that there is substantial doubt about our ability to continue as a going concern. A “going concern” opinion indicates that the financial statements have been prepared assuming we will continue as a going concern and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets, or the amounts and classification of liabilities, that may result if we do not continue as a going concern. Therefore, you should not rely on our consolidated balance sheet as an indication of the amount of proceeds that would be available to satisfy claims of creditors, and potentially be available for distribution to stockholders, in the event of liquidation.

As a development stage company with a novel technology and unproven business strategy, our limited history of operations makes an evaluation of our business and prospects difficult.

We have had a limited operating history and we are still in the process of developing our product candidates through clinical trials. Our technology is novel and involves mobilizing the immune system to fight a patient’s cancer. Immune therapies have been pursued by many parties for decades, and have experienced many failures. In addition, our technology involves personalized treatment products, a new approach to medical products that involves new product economics and business strategies, which have not yet been shown to be commercially feasible or successful. We have not yet gone through scale-up of our operations to commercial scale. This limited operating history, along with the novelty of our technology, product economics, and business strategy, and the limited scale of our operations to date, makes it difficult to assess our prospects for generating revenues commercially in the future.

We will need to expand our management and technical personnel as our operations progress, and we may not be able to recruit such additional personnel and/or retain existing personnel.

As of June 30, 2013, we employed eight full-time employees and two part-time employees. The rest of our personnel are retained on a consulting or contractor basis. Many biotech companies would typically have a larger number of employees by the time they reach late stage clinical trials. Such trials require extensive management activities and skill sets, including scientific, medical, regulatory (for FDA and foreign regulatory counterparts), manufacturing, distribution and logistics, site management, business, financial, legal, public relations outreach to both the patient community and physician community, intellectual property, administrative, regulatory (SEC), investor relations and other.

In order to fully perform all these diverse functions, with late stage trials under way at many sites across the U.S. and in Europe, we will need to expand our management and technical personnel. However, the pool of such personnel with expertise and experience with living cell products, such as our DCVax immune cell product, is very limited. In addition, we are a small company with limited resources, our business prospects are uncertain and our stock price is volatile. For some or all of such reasons, we may not be able to recruit all the management and technical personnel we need, and/or we may not be able to retain all of our existing personnel. In such event, we may have to continue our operations with a smaller than usual team of personnel, and our business and financial results may suffer.

We rely at present on third-party contract manufacturers. As a result, we may be at risk for capacity limitations and/or supply disruptions.

We currently rely upon Cognate BioServices, Inc., or Cognate, to produce all of our DCVax product candidates in the U.S., and to supervise the production of our DCVax product candidates outside the U.S. The principal shareholder of Cognate other than the employee pool is Toucan Capital Fund III, L.P., one of our major stockholders, and its affiliates. We have an agreement in place with Cognate pursuant to which Cognate has agreed to provide manufacturing and other services for the next five years, in connection with our Phase III clinical trial of DCVax-L in brain cancer, and other programs. The agreement requires us to make certain minimum monthly payments to Cognate in order to have dedicated manufacturing capacity available for our products, irrespective of whether we actually order any DCVax products. The agreement also specifies the amounts we must pay for Cognate's actual manufacturing of DCVax for patients.

We have entered into an agreement with King’s College London to manufacture DCVax for our clinical trial and our compassionate use cases. Cognate will manage and supervise the processing in London. In addition, our partner, Fraunhofer IZI Institute in Germany, has received approval and certification from the regional and national regulatory agencies in Germany for the manufacture of DCVax for GBM. We anticipate that the manufacturing facilities in the U.K. and Germany will eventually obtain the necessary approvals and be able to supply DCVax products for anywhere in Europe, however this may not turn out to be feasible, for regulatory, operational and/or logistical reasons.

Problems with the manufacturing facilities or processes of Cognate or our partners in the U.K. and/or Germany could result in a failure to produce, or a delay in production, of adequate supplies of our DCVax product candidates. A number of factors could cause interruptions or delays, including the inability of a supplier to provide raw materials, equipment malfunctions or failures, damage to a facility due to natural disasters or otherwise, changes in FDA or European regulatory requirements or standards that require modifications to our manufacturing processes, action by the FDA or European regulators, or by us that results in the halting or slowdown of production of components or finished products due to regulatory issues, our manufacturers going out of business or failing to produce product as contractually required, and/or other similar factors. Because manufacturing processes for our DCVax product candidates are highly complex, require specialized facilities and personnel that are not widely available in the industry, involve equipment and training with long lead times, and are subject to lengthy regulatory approval processes, alternative qualified production capacity may not be available on a timely basis or at all. Difficulties, delays or interruptions in the manufacturing and supply of our DCVax product candidates could require us to stop enrolling new patients into our trials, and/or require us to stop the trial or other program, increase our costs, damage our reputation and, if our product candidates are approved for sale, cause us to lose revenue or market share if our manufacturers are unable to timely meet market demands.

The manufacturing of our product candidates will have to be greatly scaled up for commercialization, and neither we nor other parties in the industry have experience with such scale-up.

As is the case with any clinical trial, our Phase III clinical trial of DCVax-L for GBM involves a number of patients that is a small fraction of the number of potential patients for whom DCVax-L may be applicable in the commercial market. The same will be true of our other clinical programs with our other DCVax product candidates. If our DCVax-L, and/or other DCVax product candidates, are approved for commercial sale, it will be necessary to greatly scale up the volume of manufacturing, far above the level needed for the trials. Neither we nor our contract manufacturers have experience with such scale-up. In addition, there are virtually no consultants or advisors in the industry who have such experience and can provide guidance or assistance, because active immune therapies such as DCVax are a fundamentally new category of product in two major ways: these active immune therapy products consist of living cells, not chemical or biologic compounds, and the products are personalized. To our knowledge, no such products have successfully completed the necessary scale-up for commercialization without material difficulties. For example, Dendreon Corporation has encountered substantial difficulties trying to scale up the manufacturing of its Provenge® product for commercialization.

The necessary specialized facilities, equipment and personnel may not be available or obtainable for the scale-up of manufacturing of our product candidates.

The manufacture of living cells requires specialized facilities, equipment and personnel which are entirely different than what is required for the manufacturing of chemical or biologic compounds. Scaling up the manufacturing of living cell products to volume levels required for commercialization will require enormous amounts of these specialized facilities, equipment and personnel — especially where, as in the case of our DCVax product candidates, the product is personalized and must be made for each patient individually. Since living cell products are so new, and have barely begun to reach commercialization, the supply of the specialized facilities, equipment and personnel needed for them has not yet developed. It may not be possible for us or our manufacturers to obtain all of the specialized facilities, equipment and personnel needed for commercialization of our DCVax product candidates. This could delay or halt our commercialization.

Our technology is novel, involves complex immune system elements, and may not prove to be effective.

Data already obtained, or in the future obtained, from pre-clinical studies and clinical trials do not necessarily predict the results that will be obtained from later pre-clinical studies and clinical trials. Over the course of several decades, there have been many different immune therapy product designs — and many product failures and company failures. To our knowledge, to date, only one active immune therapy, Provenge, has been approved by the FDA. The human immune system is complex, with many diverse elements, and the state of scientific understanding of the immune system is still limited. Some immune therapies previously developed by other parties showed surprising and unexpected toxicity in clinical trials. Other immune therapies developed by other parties delivered promising results in early clinical trials, but failed in later stage clinical trials. To date, we have only completed early stage trials in limited numbers of patients. Although the results of those trials were quite positive, those results may not be achieved in our later stage clinical trials, such as the 312-patient Phase III trial we are now conducting for GBM, and our product candidates may not ultimately be found to be effective.

Clinical trials for our product candidates are expensive and time consuming, and their outcome is uncertain.

The process of obtaining and maintaining regulatory approvals for new therapeutic products is expensive, lengthy and uncertain. Costs and timing of clinical trials may vary significantly over the life of a project owing to any or all of the following non-exclusive reasons:

Late stage clinical trials, such as our Phase III clinical trial for GBM patients, are especially expensive, typically requiring tens of millions of dollars, and take years to reach their outcomes. Such outcomes often fail to reproduce the results of earlier trials. It is often necessary to conduct multiple late stage trials (including multiple Phase III trials) in order to obtain sufficient results to support product approval, which further increases the expense. Sometimes trials are further complicated by changes in requirements while the trials are under way (for example, when the standard of care changes for the disease that is being studied in the trial). Accordingly, any of our current or future product candidates could take a significantly longer time to gain regulatory approval than we expect, or may never gain approval, either of which could delay or stop the commercialization of our DCVax product candidates.

We may be required to suspend or discontinue clinical trials due to unexpected side effects or other safety risks that could preclude approval of our product candidates.

Our clinical trials may be suspended at any time for a number of reasons. For example, we may voluntarily suspend or terminate our clinical trials if at any time we believe that they present an unacceptable risk to the clinical trial patients. In addition, the FDA or other regulatory agencies may order the temporary or permanent discontinuation of our clinical trials at any time if they believe that the clinical trials are not being conducted in accordance with applicable regulatory requirements or that they present an unacceptable safety risk to the clinical trial patients.

Administering any product candidate to humans may produce undesirable side effects. These side effects could interrupt, delay or halt clinical trials of our product candidates and could result in the FDA or other regulatory authorities denying further development or approval of our product candidates for any or all targeted indications. Ultimately, some or all of our product candidates may prove to be unsafe for human use. Moreover, we could be subject to significant liability if any volunteer or patient suffers, or appears to suffer, adverse health effects as a result of participating in our clinical trials.

We rely on third parties to assist us, on a contract services basis, in managing and monitoring all of our clinical trials. We do not have experience conducting late stage clinical trials ourselves without third party service firms, other than our current 312-patient Phase III clinical trial of DCVax-L for GBM, nor do we have experience in supervising such third parties in managing late stage, multi-hundred patient clinical trials, other than our current Phase III trial for GBM. Our lack of experience and/or our reliance on these third party service firms may result in delays or failure to complete these trials successfully and on time. If the third parties fail to perform, we may not be able to find sufficient alternative suppliers of those services in a reasonable time period, or on commercially reasonable terms, if at all. If we were unable to obtain alternative suppliers of such services, we might be forced to delay, suspend or stop our Phase III trial for GBM.

Our success will be dependent upon our ability, and our collaborative partners’ abilities, to maintain compliance with regulatory requirements, including current good manufacturing practices, or cGMP, and safety reporting obligations. The failure to comply with applicable regulatory requirements can result in, among other things, fines, injunctions, civil penalties, total or partial suspension of regulatory approvals, refusal to approve pending applications, recalls or seizures of products, operating and production restrictions and criminal prosecutions.

Regulatory approval of our product candidates may be withdrawn at any time.

After regulatory approval has been obtained for medicinal products, the product and the manufacturer are subject to continual review, including the review of adverse experiences and clinical results that are reported after our products are made available to patients, and there can be no assurance that such approval will not be withdrawn or restricted. Regulators may also subject approvals to restrictions or conditions, or impose post-approval obligations on the holders of these approvals, and the regulatory status of such products may be jeopardized if such obligations are not fulfilled. If post-approval studies are required, such studies may involve significant time and expense.

The manufacturer and manufacturing facilities we use to make any of our products will also be subject to periodic review and inspection by the FDA or EMA, as applicable. The discovery of any new or previously unknown problems with the product, manufacturer or facility may result in restrictions on the product or manufacturer or facility, including withdrawal of the product from the market. We will continue to be subject to the FDA or the European Medicines Agency, or EMA, requirements, as applicable, governing the labeling, packaging, storage, advertising, promotion, recordkeeping, and submission of safety and other post-market information for all of our product candidates, even those that the FDA or EMA, as applicable, had approved. If we fail to comply with applicable continuing regulatory requirements, we may be subject to fines, suspension or withdrawal of regulatory approval, product recalls and seizures, operating restrictions and other adverse consequences.

Our product candidates will require a different distribution model than conventional therapeutic products, and this may impede commercialization of our product candidates.

Our DCVax product candidates consist of living human immune cells. Such products are entirely different from chemical or biologic drugs, and require different handling, distribution and delivery than chemical or biologic drugs. One crucial difference is that our DCVax products must remain frozen throughout the distribution and delivery process, until the time of administration to the patient, and cannot be handled at room temperature until then. In addition, our DCVax product candidates are personalized and they involve ongoing treatment cycles over several years for each patient. Each product shipment for each patient must be tracked and managed individually. For all of these reasons, among others, we will not be able to simply use the distribution networks and processes that already exist for conventional drugs. It may take time for shipping companies, hospitals, pharmacies and physicians to adapt to the requirements for handling, distribution and delivery of these products, which may adversely affect our commercialization.

Our product candidates will require different marketing and sales methods and personnel than conventional therapeutic products. Also, we lack sales and marketing experience. These factors may result in significant difficulties in commercializing our product candidates.

The commercial success of any of our product candidates will depend upon the strength of our sales and marketing efforts. We do not have a marketing or sales force and have no experience in marketing or sales of products like our lead product, DCVax-L for GBM. To fully commercialize our product candidates, we will need to recruit and train marketing staff and a sales force with technical expertise and ability to manage the distribution of our DCVax-L for GBM. As an alternative, we could seek assistance from a corporate partner or a third party services firm with a large distribution system and a large direct sales force. However, since our DCVax products are living cell, immune therapy products, these are a fundamentally new and different type of product than are on the market today, we would still have to train such partner’s or such services firm’s personnel about our products, and would have to make changes in their distribution processes and systems to handle our products. We may be unable to recruit and train effective sales and marketing forces or our own, or of a partner or a services firm, and/or doing so may be more costly and difficult than anticipated. Such factors may result in significant difficulties in commercializing our product candidates, and we may be unable to generate significant revenues.

The availability and amount of potential reimbursement for our product candidates by government and private payers is uncertain and may be delayed and/or inadequate.

The availability and extent of reimbursement by governmental and/or private payers is essential for most patients to be able to afford expensive treatments, such as cancer treatments. In the United States, the principal decisions about reimbursement for new medicines are typically made by the Centers for Medicare & Medicaid Services, or CMS, an agency within the U.S. Department of Health and Human Services, as CMS decides whether and to what extent a new medicine will be covered and reimbursed under Medicare. Private payers tend to follow CMS to a substantial degree. It is difficult to predict what CMS will decide with respect to reimbursement for fundamentally novel products such as ours, as there is no body of established practices and precedents for these new products. To date, we are aware of only one active immune therapy that has reached the stage of a reimbursement decision (Provenge). Although CMS approved coverage and reimbursement for Provenge, and private payers followed suit, there remain substantial questions and concerns about reimbursement for Provenge, and such questions and concerns appear to be impeding sales.

Reimbursement agencies in Europe can be even more conservative than CMS in the U.S. A number of cancer drugs which have been approved for reimbursement in the U.S. have not been approved for reimbursement in certain European countries, and/or the level of reimbursement approved in Europe is lower than in the U.S.

Various factors could increase the difficulties for our DCVax products to obtain reimbursement. Costs and/or difficulties associated with the reimbursement of Provenge could create an adverse environment for reimbursement of other immune therapies, such as our DCVax products. Approval of other competing products (drugs and/or devices) for the same disease indications could make the need for our products and the cost-benefit balance seem less compelling. The cost structure of our product is not a typical cost structure for medical products, as the majority of our costs are incurred up front, when the manufacturing of the personalized product is done. Our atypical cost structure may not be accommodated in any reimbursement for our products. If we are unable to obtain adequate levels of reimbursement, our ability to successfully market and sell our product candidates will be adversely affected.

The manner and level at which reimbursement is provided for services related to our product candidates (e.g., for administration of our product to patients) is also important. If the reimbursement for such services is inadequate, that may lead to physician resistance and adversely affect our ability to market or sell our products.

The methodology under which CMS makes coverage and reimbursement determinations is subject to change, particularly because of budgetary pressures facing the Medicare program. For example, the Medicare Prescription Drug, Improvement, and Modernization Act, or Medicare Modernization Act, enacted in 2003, provided for a change in reimbursement methodology that has reduced the Medicare reimbursement rates for many drugs, including oncology therapeutics.

In markets outside the U.S., where we plan to operate in the future, the prices of medical products are subject to direct price controls and/or to reimbursement with varying price control mechanisms, as part of national health systems. In general, the prices of medicines under such systems are substantially lower than in the U.S. Some jurisdictions operate positive and/or negative list systems under which products may only be marketed once a reimbursement price has been agreed. Other countries allow companies to fix their own prices for medicines, but monitor and control company profits. The downward pressure on health care costs in general, particularly prescription drugs, has become very intense. As a result, increasingly high barriers are being erected to the entry of new products. Accordingly, in markets outside the U.S., the reimbursement for our products may be reduced compared with the U.S. and may be insufficient to generate commercially reasonable revenues and profits.

Competition in the biotechnology and biopharmaceutical industry is intense and most of our competitors have substantially greater resources than we do.

The biotechnology and biopharmaceutical industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. Several companies, such as Novartis, Amgen and Bluebird Bio, Dendreon, Celldex Therapeutics, Inc., Activartis, Oxford Biomedica plc, Argos Therapeutics, Inc., Agenus, Inc., Prima Biomed, Ltd., Avax Technologies, Inc., Immunocellular Therapeutics, Ltd., Bavarian Nordic, Bellicum Pharmaceuticals, and others are actively involved in the research and development of immune therapies or cell-based therapies for cancer. In addition, other novel technologies for cancer are under development or commercialization, such as the electro-therapy device of NovoCure™. Of these companies, only two have obtained approval of such therapy: Dendreon (for its Provenge treatment of prostate cancer) and NovoCure. Additionally, several companies, such as Medarex, Inc., Amgen, Inc., Agensys, Inc., and Genentech, Inc., are actively involved in the research and development of monoclonal antibody-based cancer therapies. Currently, a substantial number of antibody-based products are approved for commercial sale for cancer therapy, and a large number of additional ones are under development. Genentech is also engaged in several Phase III clinical trials for additional antibody-based therapeutics for a variety of cancers, and several other companies are in early stage clinical trials for such products. Many other third parties compete with us in developing alternative therapies to treat cancer, including: biopharmaceutical companies; biotechnology companies; pharmaceutical companies; academic institutions; and other research organizations, as well as some medical device companies (e.g., NovoCure and MagForce Nano Technologies AG).

We face extensive competition from companies developing new treatments for brain cancer. These include a variety of immune therapies, as mentioned above, as well as a variety of small molecule drugs and biologics drugs. There are also a number of existing drugs used for the treatment of brain cancer that may compete with our product, including, Avastin® (Roche Holding AG), Gliadel® (Eisai Co. Ltd.), and Temodar® (Merck & Co., Inc.), as well as NovoCure’s electrotherapy device.

Most of our competitors have significantly greater financial resources and expertise in research and development, manufacturing, pre-clinical testing, conducting clinical trials, obtaining regulatory approvals and marketing and sales than we do. Smaller or early-stage companies may also prove to be significant competitors, particularly if they enter into collaborative arrangements with large and established companies.

These third parties compete with us in recruiting and retaining qualified scientific and management personnel, as well as in acquiring technologies complementary to our programs, and in obtaining sites for our clinical trials and enrolling patients.

Our competitors may develop more effective or affordable products, or achieve earlier patent protection or earlier product marketing and sales. Any products developed by us may be rendered obsolete and non-competitive.

In the E.U., there exists a process for approval of generic biological medicinal products once patent protection and other forms of data and market exclusivity have expired. Arrangements for approval of generic biologics products exist and are under consideration in the U.S., as well. Other jurisdictions are considering adopting legislation that would allow the approval of generic biological medicinal products. If generic medicinal products are approved, competition from such products may substantially reduce sales of our products.

We may be exposed to potential product liability claims, and our existing insurance may not cover these claims, in whole or in part. In addition, insurance against such claims may not be available to us on reasonable terms in the future, if at all.

Our business exposes us to potential product liability risks that are inherent in the testing, manufacturing, marketing and sale of therapeutic products. We carry insurance coverage but this insurance may not cover any claims made. In the future, insurance coverage may not be available to us on commercially reasonable terms (including acceptable cost), if at all. Insurance that we obtain may not be adequate to cover claims against us. Regardless of whether they have any merit or not, and regardless of their eventual outcome, product liability claims may result in substantially decreased demand for our product candidates, injury to our reputation, withdrawal of clinical trial participants or physicians, and/or loss of revenues. Thus, whether or not we are insured, a product liability claim or product recall may result in losses that could be material.

We store, handle, use and dispose of controlled hazardous, radioactive and biological materials in our business. Our current use of these materials generally is below thresholds giving rise to burdensome regulatory requirements. Our development efforts, however, may result in our becoming subject to additional requirements, and if we fail to comply with applicable requirements we could be subject to substantial fines and other sanctions, delays in research and production, and increased operating costs. In addition, if regulated materials were improperly released at our current or former facilities or at locations to which we send materials for disposal, we could be liable for substantial damages and costs, including cleanup costs and personal injury or property damages, and we could incur delays in research and production and increased operating costs.

Insurance covering certain types of claims of environmental damage or injury resulting from the use of these materials is available but can be expensive and is limited in its coverage. We have no insurance specifically covering environmental risks or personal injury from the use of these materials and if such use results in liability, our business may be seriously harmed.

Collaborations play an important role in our business, and could be vulnerable to competition or termination.

We work with scientists and medical professionals at academic and other institutions, including UCLA, among others, some of whom have conducted research for us or have assisted in developing our research and development strategy. These scientists and medical professionals are collaborators, not our employees. They may have commitments to, or contracts with, other businesses or institutions that limit the amount of time they have available to work with us. We have little control over these individuals. We can only expect that they devote time to us and our programs as required by any license, consulting or sponsored research agreements we may have with them. In addition, these individuals may have arrangements with other companies to assist in developing technologies that may compete with our products. If these individuals do not devote sufficient time and resources to our programs, or if they provide substantial assistance to our competitors, our business could be seriously harmed.

The success of our business strategy may partially depend upon our ability to develop and maintain our collaborations and to manage them effectively. Due to concerns regarding our ability to continue our operations or the commercial feasibility of our personalized DCVax product candidates, these third parties may decide not to conduct business with us or may conduct business with us on terms that are less favorable than those customarily extended by them. If either of these events occurs, our business could suffer significantly.

We may have disputes with our collaborators, which could be costly and time consuming. Failure to successfully defend our rights could seriously harm our business, financial condition and operating results. We intend to continue to enter into collaborations in the future. However, we may be unable to successfully negotiate any additional collaboration and any of these relationships, if established, may not be scientifically or commercially successful.

Our business could be adversely affected by new legislation and/or product related issues.

Changes in applicable legislation and/or regulatory policies or discovery of problems with the product, production process, site or manufacturer may result in delays in bringing products to market, the imposition of restrictions on the product’s sale or manufacture, including the possible withdrawal of the product from the market, or may otherwise have an adverse effect on our business.

Our business activities have involved animal testing, as such testing is required before new medical products can be tested in clinical trials in human patients. Animal testing has been the subject of controversy and adverse publicity. Some organizations and individuals have attempted to stop animal testing by pressing for legislation and regulation in these areas. To the extent that the activities of such groups are successful, our business could be adversely affected. Negative publicity about us, our pre-clinical trials and our product candidates could also adversely affect our business.

Multiple late stage clinical trials of DCVax-L for GBM, our lead product, may be required before we can obtain regulatory approval.

Typically, companies conduct multiple late stage clinical trials of their product candidates before seeking product approval. Our current Phase III 312-patient clinical trial of DCVax-L for GBM is our first late stage trial. We may be required to conduct additional late stage trials with DCVax-L for GBM before we can obtain product approval. This would substantially delay our commercialization. There is also some possibility that changes requested by the FDA could complicate the application process for product approval. In addition, a number of products are under development for brain cancer and at least one (NovoCure) has been approved in the U.S. It is possible that the standard of care for brain cancer could change while our Phase III trial is still under way. This could necessitate further clinical trials with our DCVax-L product candidate for brain cancer.

Changes in manufacturing methods for DCVax-L could require us to conduct equivalency studies and/or additional clinical trials.

With biologics products, “the process is the product”: i.e., the manufacturing process is considered to be as integral to the product as is the composition of the product itself. If any changes are made in the manufacturing process, and such changes are considered material by the regulatory authorities, the company sponsor may be required to conduct equivalency studies to show that the product is equivalent under the changed manufacturing processes as under the original manufacturing processes, and/or the company sponsor may be required to conduct additional clinical trials. Our manufacturing processes have undergone some changes during the early clinical trials. Accordingly, we may be required to conduct equivalency studies, and/or additional clinical trials, before we can obtain product approval, unless the regulatory authorities are satisfied that the changes in processes do not affect the quality, efficacy or safety of the product.

We may not receive regulatory approvals for our product candidates or there may be a delay in obtaining such approvals.

Our products and our ongoing development activities are subject to regulation by regulatory authorities in the countries in which we and our collaborators and distributors wish to test, manufacture or market our products. For instance, the FDA will regulate the product in the U.S. and equivalent authorities, such as the EMA will regulate in Europe. Regulatory approval by these authorities will be subject to the evaluation of data relating to the quality, efficacy and safety of the product for its proposed use, and there can be no assurance that the regulatory authorities will find our data sufficient to support product approval of DCVax-L.

The time required to obtain regulatory approval varies between countries. In the U.S., for products without “Fast Track” status, it can take up to 18 months after submission of an application for product approval to receive the FDA's decision. Even with Fast Track status, FDA review and decision can take up 12 months. At present, we do not have Fast Track status for our lead product, DCVax-L for GBM. We plan to apply for Fast Track status, but there can be no assurance that FDA will grant us such status for DCVax-L.

Different regulators may impose their own requirements and may refuse to grant, or may require additional data before granting, an approval, notwithstanding that regulatory approval may have been granted by other regulators. Regulatory approval may be delayed, limited or denied for a number of reasons, including insufficient clinical data, the product not meeting safety or efficacy requirements or any relevant manufacturing processes or facilities not meeting applicable requirements as well as case load at the regulatory agency at the time.

We may not obtain or maintain the benefits associated with orphan drug status, including market exclusivity.

Although our lead product, DCVax-L for GBM, has been granted orphan drug status in both the U.S. and the E.U., we may not receive the benefits associated with orphan drug designation (including the benefit providing for market exclusivity for a number of years). This may result from a failure to maintain orphan drug status, or result from a competing product reaching the market that has an orphan designation for the same disease indication. Under U.S. and E.U. rules for orphan drugs, if such a competing product reaches the market before ours does, the competing product could potentially obtain a scope of market exclusivity that limits or precludes our product from being sold in the U.S. for seven years or from being sold in the E.U. for ten years. Also, in the E.U., even after orphan status has been granted, that status is re-examined shortly prior to the product receiving any regulatory approval. The EMA must be satisfied that there is evidence that the product offers a significant benefit relative to existing therapies, in order for the therapeutic product to maintain its orphan drug status. Accordingly, our product candidates will have to re-qualify for orphan drug status prior to any potential product approval in the E.U.

Our intellectual property rights may be overturned, narrowed or blocked, and may not provide sufficient commercial protection for our product candidates, or third parties may infringe upon our intellectual property.

The patent position of biotechnology and pharmaceutical companies generally is highly uncertain, involves complex legal and factual questions and has in recent years been the subject of much litigation. As a result, the issuance, scope, validity, enforceability and commercial value of our patent rights are highly uncertain. Patent laws afford only limited protection and may not protect our rights to the extent necessary to sustain any competitive advantage we may have. In addition, the laws of some foreign countries do not protect proprietary rights to the same extent as the laws of the United States, and we may encounter significant problems in protecting our proprietary rights in those countries. Moreover patents and patent applications relating to living cell products are relatively new, involve complex factual and legal issues, and are largely untested in litigation — and as a result, are uncertain. Our pending and future patent applications may not result in patents being issued which adequately protect our technology or products or which effectively prevent others from commercializing the same or competitive technologies and products. As a result, we may not be able to obtain meaningful patent protection for our commercial products, and our business may suffer as a result. Third parties may challenge our existing patents, and such challenges could result in overturning or narrowing some of our patents. Even if our patents are not challenged, third parties could assert that their patents block our use of technology covered by some or all of our patents

As of June 30, 2013, we had over 73 pending patent applications and 119 issued patents worldwide relating to our product candidates and related matters such as manufacturing processes. The issued patents expire at various dates from 2015 to 2029. Our issued patents may be challenged, and such challenges may result in reductions in scope, cancellations or invalidations. Our pending patent applications may not result in issued patents. Moreover, our patents and patent applications may not be sufficiently broad to prevent others from using substantially similar technologies or from developing competing products. We also face the risk that others may independently develop similar or alternative technologies, or design around our patented technologies. As a result, no assurance can be given that any of our pending or future patent applications will be granted, that the scope of any patent protection currently granted or that may be granted in the future will exclude competitors or provide us with competitive advantages, that any of the patents that have been or may be issued to us will be held valid if subsequently challenged, or that other parties will not claim rights to or ownership of our patents or other proprietary rights that we hold.

We have taken security measures (including execution of confidentiality agreements) to protect our proprietary information, especially proprietary information that is not covered by patents or patent applications. These measures, however, may not provide adequate protection for our trade secrets or other proprietary information. In addition, others may independently develop substantially equivalent proprietary information or techniques or otherwise gain access to our trade secrets.

We may be exposed to claims or lawsuits that our products infringe patents or other proprietary rights of other parties.

Our commercial success depends upon our ability and the ability of our collaborators to develop, manufacture, market and sell our product candidates and use our proprietary technologies without infringing the proprietary rights of third parties. We have not conducted a comprehensive freedom-to-operate review to determine whether our proposed business activities or use of certain of the technology covered by patent rights owned by us would infringe patents issued to third parties.

There is a substantial amount of litigation involving patent and other intellectual property rights in the biotechnology and biopharmaceutical industries generally. The patent landscape is especially uncertain in regard to cell therapy products, as it involves complex legal and factual questions for which important legal principles remain unresolved. We may become party to, or threatened with, future adversarial proceedings or litigation regarding intellectual property rights with respect to our products and technology, including interference proceedings before the U.S. Patent and Trademark Office. Third parties may assert infringement claims against us based on existing patents or patents that may be granted in the future. If we are found to infringe a third party’s intellectual property rights, we could be required to obtain a license from such third party to continue developing and marketing our products and technology. However, we may not be able to obtain any required license on commercially reasonable terms or at all. Even if we were able to obtain a license, it could be non-exclusive, thereby giving our competitors access to the same technologies licensed to us. We could be forced, including by court order, to cease commercializing the infringing technology or product. In addition, we could be found liable for monetary damages. If the infringement is found to be willful, we could be liable for trebled damages. A finding of infringement could prevent us from commercializing our product candidates or force us to cease some of our business operations, which could materially harm our business. Claims that we have misappropriated the confidential information or trade secrets of third parties could have a similar negative impact on our business.

We have already been exposed to one patent lawsuit by a large company, which we vigorously defended and ultimately settled. We have recently also been exposed to claims (without a lawsuit) by a competitor asserting or implying (and commentaries based on the claims) that a recently issued patent covers our products. While we believe these claims to be without merit, if a lawsuit for infringement were brought against us, there can be no assurance that a judge or jury would agree with our position. In the future, we may again be exposed to claims by third parties — with or without merit — that our products infringe their intellectual property rights.

Even if resolved in our favor, litigation or other legal proceedings relating to intellectual property claims may cause us to incur significant expenses, and could distract our technical and management personnel from their normal responsibilities. In addition, there could be public announcements of the results of hearings, motions or other interim proceedings or developments and if securities analysts or investors perceive these results to be negative, it could have a substantial adverse effect on the price of our common stock. Such litigation or proceedings could substantially increase our operating losses and reduce the resources available for development activities or any future sales, marketing or distribution activities. We may not have sufficient financial or other resources to adequately conduct such litigation or proceedings. Some of our competitors may be able to sustain the costs of such litigation or proceedings more effectively than we can because of their greater financial resources. Uncertainties resulting from the initiation and continuation of patent litigation or other proceedings could have a material adverse effect on our ability to compete in the marketplace.

Unlike many pharmaceutical companies that have a number of products in development and which utilize many different technologies, we are dependent on the success of our DCVax platform technology. While the DCVax technology has a wide scope of potential use, and is embodied in several different product lines for different clinical situations, if the core DCVax technology is not effective or is not commercially viable, our business could fail. We do not currently have other technologies that could provide alternative support for us.

The market price of our common stock may be volatile and adversely affected by several factors.

The share prices of publicly traded biotechnology and emerging pharmaceutical companies, particularly companies without consistent product revenues and earnings, can be highly volatile and are likely to remain highly volatile in the future. The price which investors may realize in sales of their shares of our common stock may be materially different than the price at which our common stock is quoted, and will be influenced by a large number of factors, some specific to us and our operations, and some unrelated to our operations. Such factors may cause the price of our stock to fluctuate frequently and substantially. Such factors may include large purchases or sales of our common stock, positive or negative events relating to other companies developing immune therapies for cancer, positive or negative events relating to healthcare and the overall pharmaceutical and biotech sector, currency fluctuations, legislative or regulatory changes, and/or general economic conditions. In the past, shareholder class action litigation has been brought against other companies that experienced volatility in the market price of their shares. Whether or not meritorious, litigation brought against a company following fluctuations in the trading price of its common stock can result in substantial costs, divert management’s attention and resources, and harm the company’s financial condition and results of operations.

The market for our common stock may be limited, because our common stock is subject to “penny stock” rules.

Our common stock is subject to the SEC’s “penny stock” rules. As a result, broker-dealers may experience difficulty in completing customer transactions, and trading activity in our securities may be adversely affected. Under the “penny stock” rules promulgated under the Securities Exchange Act of 1934, as amended, or the Exchange Act, broker-dealers who recommend such securities to persons other than institutional accredited investors must:

As a result of these rules, broker-dealers may find it difficult to effectuate customer transactions, and trading activity in our common stock may be adversely affected. As a result, the market price of our common stock may be depressed, and stockholders may find it more difficult to sell our common stock.

Toucan Capital and its affiliates are the principal holders of our shares of common stock, and this concentration of ownership may have a negative effect on the market price of our common stock.

As of June 30, 2013, Toucan Capital and its affiliates (including Cognate BioServices, Toucan Partners and Linda Powers, who also serves as our Chief Executive Officer and Chairperson of the Board of Directors), collectively, owned an aggregate of 10,809,992 shares of our outstanding common stock, representing approximately 35% of our issued and outstanding common stock on that date. This does not include 2,902,072 shares of common stock issued to Cognate BioServices, Inc. upon the conversion of $11.6 million in notes payable in August 2013. This concentration of ownership may adversely affect the trading price of our common stock because investors may perceive disadvantages in owning stock of companies with controlling stockholders. Toucan Capital and its affiliates have the ability to exert substantial influence over all matters requiring approval by our stockholders, including the election and removal of directors and any proposed merger, consolidation or sale of all or substantially all of our assets. This influence could have the effect of delaying, deferring or preventing a change in control, or impeding a merger or consolidation, takeover or other business combination that could be favorable to investors.

The requirements of the Sarbanes-Oxley Act of 2002 and other U.S. securities laws impose substantial costs, and may drain our resources and distract our management.

We are subject to certain of the requirements of the Sarbanes-Oxley Act of 2002 in the U.S., as well as the reporting requirements under the Exchange Act. The Exchange Act requires, among other things, filing of annual reports on Form 10-K, quarterly reports on Form 10-Q and periodic reports on Form 8-K following the happening of certain material events, with respect to our business and financial condition. The Sarbanes-Oxley Act requires, among other things, that we maintain effective disclosure controls and procedures and internal controls over financial reporting. Our existing controls have some weaknesses, as described below. Meeting the requirements of the Exchange Act and the Sarbanes-Oxley Act may strain our resources and may divert management's attention from other business concerns, both of which may have a material adverse effect on our business.

Our management and our independent auditors have identified internal control deficiencies, which our management and our independent auditor believe constitute material weaknesses.

In connection with the preparation of our financial statements for the year ended December 31, 2012, and prior years, our management and our independent auditor identified certain internal control deficiencies that, in the aggregate, represent material weaknesses, including:

As part of our independent auditors’ communications with our audit committee with respect to audit procedures for the year ended December 31, 2012, our independent auditors informed the audit committee that these deficiencies constituted material weaknesses, as defined by Auditing Standard No. 5, “An Audit of Internal Control Over Financial Reporting that is Integrated with an Audit of Financial Statements and Related Independence Rule and Conforming Amendments,” established by the Public Company Accounting Oversight Board, or PCAOB. We have begun taking appropriate and reasonable steps, and will continue and complete such steps in due course, to make the necessary improvements to address these deficiencies, but the timing of such steps is uncertain and the availability of funding and resources for such steps are also uncertain. Our ability to retain or attract qualified individuals to serve on our Board and to take on key management roles within our company is also uncertain. Our failure to successfully complete the remedies of the existing weaknesses could lead to heightened risk for financial reporting mistakes and irregularities, and/or lead to a loss of public confidence in our internal controls that could have a negative effect on the market price of our common stock.

We do not intend to pay any cash dividends in the foreseeable future and, therefore, any return on your investment in our common stock must come from increases in the market price of our common stock.

We have not paid any cash dividends on our common stock to date in our history, and we do not intend to pay cash dividends on our common stock in the foreseeable future. We intend to retain future earnings, if any, for reinvestment in the development and expansion of our business. Also, any credit agreements which we may enter into with institutional lenders may restrict our ability to pay dividends. Therefore, any return on your investment in our capital stock must come from increases in the fair market value and trading price of our common stock. Such increases in the trading price of our stock may not occur.

Our certificate of incorporation and bylaws and Delaware law, and the shareholders rights plan we intend to adopt, have anti-takeover provisions that could discourage, delay or prevent a change in control, which may cause our stock price to decline.

Our certificate of incorporation and bylaws and Delaware law contain provisions which could make it more difficult for a third party to acquire us, even if closing such a transaction would be beneficial to our stockholders. We are authorized to issue up to 40,000,000 shares of preferred stock. This preferred stock may be issued in one or more series, the terms of which may be determined at the time of issuance by our Board of Directors without further action by stockholders. The terms of any series of preferred stock may include voting rights (including the right to vote as a series on particular matters), preferences as to dividend, liquidation, conversion and redemption rights and sinking fund provisions. No preferred stock is currently outstanding. The issuance of any preferred stock could materially adversely affect the rights of the holders of our common stock, and therefore, reduce the value of our common stock. In particular, specific rights granted to future holders of preferred stock could be used to restrict our ability to merge with, or sell our assets to, a third party and thereby preserve control by the present management.

Provisions of our certificate of incorporation and bylaws and Delaware law also could have the effect of discouraging potential acquisition proposals or making a tender offer or delaying or preventing a change in control, including changes a stockholder might consider favorable. Such provisions may also prevent or frustrate attempts by our stockholders to replace or remove our management. In particular, the certificate of incorporation and bylaws and Delaware law, as applicable, among other things:

We expect to adopt a shareholder rights plan and declare a dividend distribution of one right for each outstanding share of common stock as fixed by our Board of Directors. Each right, when exercisable, will entitle the registered holder to purchase from us shares of a new series of preferred stock on the terms stated in the rights plan. The rights will generally separate from the common stock and become exercisable if any person or group acquires or announces a tender offer to acquire 15% or more of our outstanding common stock without the consent of our Board of Directors. Because the rights may substantially dilute the stock ownership of a person or group attempting to take us over without the approval of our Board of Directors, our stockholder rights plan could make it more difficult for a third party to acquire us (or a significant percentage of our outstanding capital stock) without first negotiating with our Board of Directors.

We are also subject to Section 203 of the Delaware General Corporation Law which, subject to certain exceptions, prohibits “business combinations” between a publicly-held Delaware corporation and an “interested stockholder,” which is generally defined as a stockholder who becomes a beneficial owner of 15% or more of a Delaware corporation’s voting stock for a three-year period following the date that such stockholder became an interested stockholder.

These provisions are expected to discourage certain types of coercive takeover practices and inadequate takeover bids and to encourage persons seeking to acquire control of our company to first negotiate with our Board. These provisions may delay or prevent someone from acquiring or merging with us, which may cause the market price of our common stock to decline.

We might not be able to maintain the listing of our common stock on The NASDAQ Capital Market.

Our common stock began listing on The NASDAQ Capital Market on December 12, 2012, under the symbol “NWBO.” We might not be able to maintain the listing standards of that exchange. If we fail to maintain the listing requirements, our common stock might move to the Over the Counter Bulletin Board or in the “pink sheets” maintained by Pink OTC Markets, Inc. The OTC Bulletin Board and the “pink sheets” are generally considered to be markets that are less efficient and less broad than The NASDAQ Capital Market. Our common stock was previously quoted on the OTC Bulletin Board from December 23, 2002 to July 23, 2012.

Our management will have broad discretion over the use of the net proceeds from this offering and we may use the net proceeds in ways with which you disagree or which do not produce beneficial results.

We currently intend to use the net proceeds from this offering to fund our research and development activities and for working capital and general corporate purposes. We have not allocated specific amounts of the net proceeds from this offering for any of the foregoing purposes. Accordingly, our management will have significant discretion and flexibility in applying the net proceeds of this offering. You will be relying on the judgment of our management with regard to the use of these net proceeds, and you will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. It is possible that the net proceeds will be invested in a way that does not yield a favorable, or any, return for us or our stockholders. The failure of our management to use such funds effectively could have a material adverse effect on our business, prospects, financial condition, and results of operation.

A substantial number of shares of common stock may be sold in the market following this offering, which may depress the market price for our common stock.

Sales of a substantial number of shares of our common stock in the public market following this offering could cause the market price of our common stock to decline. A substantial majority of the outstanding shares of our common stock are, and the shares of common stock sold in this offering upon issuance and the shares of common stock underlying the warrants will be, freely tradable without restriction or further registration under the Securities Act. In addition, as of March 31, 2013, 13,728,411 shares of our common stock are issuable upon exercise of outstanding options and warrants.

You will experience immediate dilution in the book value per share of the securities you purchase in this offering.

Because the price per share of our common stock being offered is substantially higher than the net tangible book value per share of our common stock, you will suffer substantial dilution in the net tangible book value of the common stock you purchase in this offering. Based on a public offering price of $3.35 per share, and a net tangible book value per share of our common stock of $(1.03) as of March 31, 2013, if you purchase shares of common stock in this offering, you will suffer immediate and substantial dilution of $3.80 per share in the net tangible book value of the common stock you purchase. See “Dilution” for a more detailed discussion of the dilution you will incur if you purchase our securities in this offering.

If you purchase the securities sold in this offering, you may experience dilution if we issue additional equity securities in future fundraising transactions.

If we issue additional common stock, or securities convertible into or exchangeable or exercisable for common stock, our stockholders, including investors who purchase shares in this offering, will experience dilution, and any such issuances may result in downward pressure on the price of our common stock.

There is no public market for the warrants to purchase common stock being sold in this offering.

The warrants will not be listed for trading on any stock exchange. There is no established public trading market for the warrants being offered in this offering and we do not expect a market to develop. Without an active market, the liquidity of the warrants will be limited. Further, the existence of the warrants may act to reduce both the trading volume and the trading price of our common stock.

We estimate that the net proceeds from the sale of the units we are offering will be approximately $13.7 million, based on the offering price of $3.35 per unit, and after deducting the placement agent fees, the fees of Summer Street Research Partners and $200,000 of estimated offering expenses payable by us.

We intend to use the net proceeds from this offering to fund our research and development activities (including clinical trials), and for working capital and other general corporate purposes.

We have not yet determined the amount of net proceeds to be used specifically for any of the foregoing purposes. Accordingly, our management will have significant discretion and flexibility in applying the net proceeds from this offering. Pending any use, as described above, we intend to invest the net proceeds in high-quality, short-term, interest-bearing securities.

We have never declared or paid cash dividends on our capital stock. We currently intend to retain our future earnings, if any, for use in our business and therefore do not anticipate paying cash dividends in the foreseeable future. Payment of future dividends, if any, will be at the discretion of our board of directors after taking into account various factors, including our financial condition, operating results, current and anticipated cash needs and plans for expansion.

If you purchase units in this offering, your interest will be diluted to the extent of the difference between the offering price per unit of our common stock and the net tangible book value per share of our common stock after this offering. Our net tangible book value as of March 31, 2013 was $(28.1) million, or $(1.03) per share of common stock. “Net tangible book value” is total assets minus the sum of liabilities and intangible assets. “Net tangible book value per share” is net tangible book value divided by the total number of shares of common stock outstanding.

After giving effect to the sale by us of 4,477,612 shares of our common stock underlying units offered in this offering at an offering price of $3.35 per unit, and after deducting the placement agent fees, the fees of Summer Street Research Partners and $200,000 of estimated offering expenses that we will pay, our net tangible book value as of March 31, 2013 would have been approximately $(14.3) million, or $(0.45) per share of common stock. This amount represents an immediate increase in net tangible book value of $0.58 per share to existing stockholders and an immediate dilution of $3.80 per share to purchasers in this offering.

The above table is based on 27,140,417 shares outstanding as of March 31, 2013 and excludes, as of that date:

To the extent that any outstanding options or warrants are exercised, new options are issued under our Stock Incentive Plans, or we otherwise issue additional shares of common stock in the future, at a price less than the public offering price, there will be further dilution to new investors.

The following table sets forth our cash and cash equivalents and our capitalization as of March 31, 2013 on:

The pro forma and pro forma as adjusted number of shares to be outstanding immediately after this offering as shown above is based on 27,140,417 shares outstanding as of March 31, 2013 and excludes, as of that date:

In this offering, we are offering up to 4,477,612 units, consisting of an aggregate of 4,477,612 shares of common stock and warrants to purchase 2,238,806 additional shares of common stock. Each unit consists of one share of common stock, one long-term warrant to purchase 0.25 shares of common stock at an exercise price of $4.00 per share, and one over-allotment warrant to purchase 0.25 shares of common stock at an exercise price of $3.35 per share. Units will not be issued or certificated. The shares of common stock and warrants are immediately separable and will be issued separately. This prospectus also relates to the offering of shares of our common stock upon exercise, if any, of the warrants.

The material terms and provisions of our common stock and each other class of our securities which qualifies or limits our common stock are described under the caption “Description of Capital Stock” starting on page 18 of the accompanying prospectus.

The warrants offered in this offering will be issued pursuant to a securities purchase agreement between each of the purchasers and us. You should review a copy of the form of securities purchase agreement and the form of warrant, each of which has been filed by us as an exhibit to a Current Report on Form 8-K filed with the Securities and Exchange Commission in connection with this offering, and which is incorporated by reference into the registration statement of which this prospectus supplement forms a part, for a complete description of the terms and conditions applicable to the warrants. The terms of the long-term warrants and the over-allotment warrants are identical with the exception of the exercise price and expiration date, which are described in further detail below. The following is a brief summary of the material terms of the warrants and is subject in all respects to the provisions contained in the warrants.

Exercisability. The long-term warrants are exercisable six months after issuance and at any time up to the date that is five years from the date that they become exercisable. The over-allotment warrants are exercisable immediately upon issuance and will expire one year after the date of issuance. The warrants will be exercisable, at the option of each holder, in whole or in part by delivering to us a duly executed exercise notice accompanied by payment in full for the number of shares of our common stock purchased upon such exercise (except in the case of a cashless exercise as discussed below). Unless otherwise specified in the warrant, the holder will not have the right to exercise any portion of the warrant if the holder (together with its affiliates) would beneficially own in excess of 9.99% of the number of shares of our common stock outstanding immediately after giving effect to the exercise, as such percentage ownership is determined in accordance with the terms of the warrants.

Cashless Exercise. In the event that a registration statement covering shares of common stock underlying the warrants is not available for the resale of such shares of common stock underlying the warrants, the holder may, in its sole discretion, exercise the warrant in whole or in part and, in lieu of making the cash payment otherwise contemplated to be made to us upon such exercise in payment of the aggregate exercise price, elect instead to receive upon such exercise the net number of shares of common stock determined according to the formula set forth in the warrant. In no event shall we be required to make any cash payments or net cash settlement to the registered holder in lieu of issuance of common stock underlying the warrants.

Exercise Price. The initial exercise price per share of common stock purchasable upon exercise of the long-term warrants is $4.00 per share. The initial exercise price per share of common stock purchasable upon exercise of the over-allotment warrants is $3.35 per share. The exercise price of the warrants is subject to appropriate adjustment in the event of certain stock dividends and distributions, stock splits, stock combinations, reclassifications or similar events affecting our common stock and also upon any distributions of assets, including cash, stock or other property to our stockholders.

Certain Adjustments. The exercise price and the number of shares of common stock purchasable upon the exercise of the warrants are subject to adjustment upon the occurrence of specific events, including stock dividends, stock splits, combinations and reclassifications of our common stock.

Subsequent Rights Offerings. If at any time while the warrants are outstanding, we issue rights, options or warrants to all holders of our common stock (and not to the holder of the warrants) entitling them to subscribe for or purchase shares of our common stock at a price per share less than the volume weighted average price, or VWAP, on the record date mentioned below, then the exercise price shall be multiplied by a fraction, of which the denominator shall be the number of shares of the common stock outstanding on the date of issuance of such rights, options or warrants plus the number of additional shares of common stock offered for subscription or purchase, and of which the numerator shall be the number of shares of common stock outstanding on the date of issuance of such rights, options or warrants plus the number of shares which the aggregate offering price of the total number of shares so offered (assuming receipt by us in full of all consideration payable upon exercise of such rights, options or warrants) would purchase at such VWAP. Such adjustment shall be made whenever such rights, options or warrants are issued, and shall become effective immediately after the record date for the determination of stockholders entitled to receive such rights, options or warrants.

Transferability. Subject to applicable laws, the warrants may be transferred at the option of the holders upon surrender of the warrants to us together with the appropriate instruments of transfer.

Fundamental Transaction. If, at any time while the warrants are outstanding, (1) we consolidate or merge with or into another corporation and we are not the surviving corporation, (2) we sell, lease, license, assign, transfer, convey or otherwise dispose of all or substantially all of our assets, (3) any purchase offer, tender offer or exchange offer (whether by us or another individual or entity) is completed pursuant to which holders of our shares of common stock are permitted to sell, tender or exchange their shares of common stock for other securities, cash or property and has been accepted by the holders of 50% or more of our outstanding shares of common stock, (4) we effect any reclassification or recapitalization of our shares of common stock or any compulsory share exchange pursuant to which our shares of common stock are converted into or exchanged for other securities, cash or property, or (5) we consummate a stock or share purchase agreement or other business combination with another person or entity whereby such other person or entity acquires more than 50% of our outstanding shares of common stock, each referred to as a Fundamental Transaction, then upon any subsequent exercise of the warrants, the holders thereof will have the right to receive the same amount and kind of securities, cash or property as it would have been entitled to receive upon the occurrence of such Fundamental Transaction if it had been, immediately prior to such Fundamental Transaction, the holder of the number of warrant shares then issuable upon exercise of the warrant, and any additional consideration payable as part of the Fundamental Transaction.

Rights as a Stockholder. Except as otherwise provided in the warrants or by virtue of such holder's ownership of shares of our common stock, the holder of a warrant does not have the rights or privileges of a holder of our common stock, including any voting rights, until the holder exercises the warrant.

No Warrant Agent or Exchange Listing. We will maintain the warrant register; the warrants will not be issued in under a warrant agency agreement between us and a third party. The warrants will not be listed on any exchange.

We have entered into a placement agent agreement, dated as of August 8, 2013, with Oppenheimer & Co. Inc. Subject to the terms and conditions contained in the placement agent agreement, Oppenheimer & Co. Inc. has agreed to act as the placement agent in connection with the sale of up to 4,477,612 units, with each unit consisting of one share of common stock, one long-term warrant to purchase 0.25 shares of common stock, and one over-allotment warrant to purchase 0.25 shares of common stock. The placement agent is not purchasing or selling any securities by this prospectus supplement or the accompanying prospectus, nor is it required to arrange the purchase or sale of any specific number or dollar amount of the securities, but it has agreed to use its best efforts to solicit purchasers for the securities in this offering. There is no required minimum number of securities that must be sold as a condition to completion of the offering.

We will enter into a securities purchase agreement directly with investors in connection with this offering, and we will only sell to investors who have entered into the securities purchase agreement. Our obligation to issue and sell units to investors is subject to the conditions set forth in the securities purchase agreement, which may be waived by us in our discretion. An investor’s obligation to purchase units is subject to conditions set forth in the securities purchase agreement, which may be waived by the investor.

Unless investors instruct us otherwise, we will deliver the shares of common stock being issued to the investors electronically upon receipt of investor funds for the purchase of the units offered pursuant to this prospectus supplement, and we will issue the warrants to investors. We expect to deliver the shares of our common stock and the warrants being offered pursuant to this prospectus supplement on or about August 14, 2013.

We have agreed to pay Oppenheimer & Co. Inc., our lead placement agent, placement agent commissions and fees in an amount equal to 6.5% of the aggregate proceeds of this offering. The following table shows the estimated per unit and total cash fees we will pay to Oppenheimer & Co. Inc. in connection with the sale of the securities offered pursuant to this prospectus supplement and the accompanying prospectus.

However, because there is no minimum offering amount required as a condition to closing of this offering, the actual total offering commissions, if any, may be substantially less than the total offering amounts set forth above. We estimate the total expenses of this offering, excluding the placement agency fees and fees payable to Summer Street Research Partners as discussed below, will be approximately $200,000.

We have engaged Summer Street Research Partners, or Summer Street, for financial advisory services in connection with capital raising activities and other advisory services, including this offering. Summer Street is acting as the co-placement agent in this offering. For its services, Summer Street will receive a cash fee of $97,500.

The placement agent has informed us that it will not engage in over-allotment, stabilizing transactions or syndicate covering transactions in connection with this offering.

The placement agent agreement provides that the obligations of the placement agent are subject to certain conditions precedent, including the absence of any material adverse changes in our business and the receipt of certain certificates, opinions and letters from us, our counsels and our auditors.

We have agreed to indemnify the placement agent and specified other persons against certain civil liabilities, including liabilities under the Securities Act or the Exchange Act, and to contribute to payments that the placement agent may be required to make in respect of such liabilities.

Our officers and directors have signed lock-up agreements, pursuant to which they have agreed to not, directly or indirectly, offer, sell, agree to sell or otherwise transfer or dispose of any shares of our common stock or any securities convertible into or exchangeable for shares of our common stock, without the prior written consent of Oppenheimer & Co. Inc. for a period of 45 days after the date of this prospectus.

Our common stock is traded on the NASDAQ Capital Market under the symbol “NWBO.”

The placement agent may distribute this prospectus supplement and the accompanying prospectus electronically.

The placement agent agreement will be included as an exhibit to a Current Report on Form 8-K that we will file with the SEC and that will be incorporated by reference into the registration statement of which this prospectus supplement forms a part.

The placement agent or its affiliates may in the future provide investment banking, commercial banking and/or other services to us from time to time, for which they may in the future receive customary fees and expenses.

The validity of the securities being offered hereby will be passed upon by Wyrick Robbins Yates & Ponton, LLP, Raleigh, North Carolina. Mintz Levin Cohn Ferris Glovsky and Popeo PC, New York, New York, is acting as counsel for the placement agent in connection with certain legal matters related to this offering.

The audited financial statements incorporated by reference in this prospectus have been so incorporated by reference in reliance upon the report of Peterson Sullivan LLP, independent registered public accountants, upon the authority of said firm as experts in accounting and auditing in giving said report.

We are subject to the reporting requirements of the Securities Exchange Act of 1934, as amended, and file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read and copy these reports, proxy statements and other information at the SEC’s public reference facilities at 100 F Street, N.E., Room 1580, Washington, D.C. 20549. You can request copies of these documents by writing to the SEC and paying a fee for the copying cost. Please call the SEC at 1-800-SEC-0330 for more information about the operation of the public reference facilities. SEC filings are also available at the SEC’s web site at http://www.sec.gov. Our common stock is listed on The NASDAQ Capital Market, and you can read and inspect our filings at the offices of the National Association of Securities Dealers, Inc. at 1735 K Street, Washington, D.C. 20006.

This prospectus is only part of a registration statement on Form S-3 that we have filed with the SEC under the Securities Act of 1933, as amended, and therefore omits certain information contained in the registration statement. We have also filed exhibits and schedules with the registration statement that are excluded from this prospectus, and you should refer to the applicable exhibit or schedule for a complete description of any statement referring to any contract or other document. You may inspect a copy of the registration statement, including the exhibits and schedules, without charge, at the public reference room or obtain a copy from the SEC upon payment of the fees prescribed by the SEC.

The SEC allows us to “incorporate by reference” information that we file with them. Incorporation by reference allows us to disclose important information to you by referring you to those other documents. The information incorporated by reference is an important part of this prospectus, and information that we file later with the SEC will automatically update and supersede this information. We filed a registration statement on Form S-3 under the Securities Act of 1933, as amended, with the SEC with respect to the securities being offered pursuant to this prospectus. This prospectus omits certain information contained in the registration statement, as permitted by the SEC. You should refer to the registration statement, including the exhibits, for further information about us and the securities being offered pursuant to this prospectus. Statements in this prospectus regarding the provisions of certain documents filed with, or incorporated by reference in, the registration statement are not necessarily complete and each statement is qualified in all respects by that reference. Copies of all or any part of the registration statement, including the documents incorporated by reference or the exhibits, may be obtained upon payment of the prescribed rates at the offices of the SEC listed above in “Where You Can Find More Information.” The documents we are incorporating by reference are:

In addition, all documents (other than current reports furnished under Item 2.02 or Item 7.01 of Form 8-K and exhibits filed in such forms that are related to such items unless such Form 8-K expressly provides to the contrary) subsequently filed by us pursuant to Section 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, before the date our offering is terminated or completed are deemed to be incorporated by reference into, and to be a part of, this prospectus.

Any statement contained in this prospectus or in a document incorporated or deemed to be incorporated by reference into this prospectus will be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus or any other subsequently filed document that is deemed to be incorporated by reference into this prospectus modifies or supersedes the statement. Any statement so modified or superseded will not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

We will furnish without charge to you, on written or oral request, a copy of any or all of the documents incorporated by reference, including exhibits to these documents. You should direct any requests for documents to Northwest Biotherapeutics, Inc., 4800 Montgomery Lane, Suite 800, Bethesda, MD 20814, (240) 497-9024.

You should rely only on information contained in, or incorporated by reference into, this prospectus and any prospectus supplement. We have not authorized anyone to provide you with information different from that contained in this prospectus or incorporated by reference in this prospectus. We are not making offers to sell the securities in any jurisdiction in which such an offer or solicitation is not authorized or in which the person making such offer or solicitation is not qualified to do so or to anyone to whom it is unlawful to make such offer or solicitation.

Prospectus

[GRAPHIC MISSING]

$100,000,000 of
Common Stock,
Preferred Stock,
Warrants
Debt Securities, and/or
Units

From time to time, we may offer up to $100,000,000 of any combination of the securities described in this prospectus, either individually or in units, in one or more offerings in amounts, at prices and on the terms that we will determine at the time of offering. We may also offer common stock or preferred stock upon conversion of debt securities, common stock upon conversion of preferred stock, or common stock, preferred stock or debt securities upon the exercise of warrants.

Each time we sell securities, we will provide specific terms of the securities offered in a supplement to this prospectus. The prospectus supplement may also add, update or change information contained in this prospectus. We will specify in any accompanying prospectus supplement the terms of any offering. You should read this prospectus and the applicable prospectus supplement, as well as any documents incorporated by reference in this prospectus and any prospectus supplement, carefully before you invest in any securities. This prospectus may not be used by us to consummate a sale of securities unless accompanied by the applicable prospectus supplement.

We will sell these securities directly to our stockholders or to other purchasers or through agents on our behalf or through underwriters or dealers as designated from time to time. If any agents or underwriters are involved in the sale of any of these securities, the applicable prospectus supplement will provide the names of the agents or underwriters and any applicable fees, commissions or discounts.

Our common stock and warrants trade on The NASDAQ Capital Market under the trading symbols “NWBO” and “NWBOW,” respectively. On January 24, 2013, the last reported sale price of our common stock and warrants was $3.26 and $1.66, respectively. We recommend that you obtain current market quotations for our common stock and warrants prior to making an investment decision.

You should carefully read this prospectus, the prospectus supplement relating to any specific offering of securities and all information incorporated by reference herein and therein.

Investing in our securities involves a high degree of risk. These risks are discussed in this prospectus under “Risk Factors” beginning on page 4 and in the documents incorporated by reference into this prospectus.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or determined if this prospectus is truthful or complete. Any representation to the contrary is a criminal offense.

The date of this prospectus is February 5, 2013

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, or SEC, utilizing a “shelf” registration process. Under this shelf registration process, we may offer shares of our common stock and preferred stock, various series of debt securities and/or warrants to purchase any of such securities, either individually or in units, in one or more offerings, up to a total dollar amount of $100,000,000. This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of securities under this prospectus, we will provide a prospectus supplement that will contain specific information about the terms of that offering.

This prospectus does not contain all of the information included in the registration statement. For a more complete understanding of the offering of the securities, you should refer to the registration statement, including its exhibits. Prospectus supplements may also add, update or change information contained or incorporated by reference in this prospectus. However, no prospectus supplement will fundamentally change the terms that are set forth in this prospectus or offer a security that is not registered and described in this prospectus at the time of its effectiveness. This prospectus, together with the applicable prospectus supplements and the documents incorporated by reference into this prospectus and the applicable prospectus supplement, includes all material information relating to this offering. You should carefully read this prospectus, the applicable prospectus supplement, the information and documents incorporated herein and therein by reference and the additional information under the heading “Where You Can Find More Information” before making an investment decision.

You should rely only on the information we have provided or incorporated by reference in this prospectus or any prospectus supplement. We have not authorized anyone to provide you with information different from that contained or incorporated by reference in this prospectus. No dealer, salesperson or other person is authorized to give any information or to represent anything not contained or incorporated by reference in this prospectus. You must not rely on any unauthorized information or representation. This prospectus is an offer to sell only the securities offered hereby, but only under circumstances and in jurisdictions where it is lawful to do so. You should assume that the information in this prospectus or any prospectus supplement is accurate only as of the date on the front of the document and that any information we have incorporated herein by reference is accurate only as of the date of the document incorporated by reference, regardless of the time of delivery of this prospectus or any sale of a security.

To the extent there are inconsistencies between any prospectus supplement, this prospectus and any documents incorporated by reference, the document with the most recent date will control.

This prospectus may not be used to consummate sales of our securities, unless it is accompanied by a prospectus supplement.

Unless the context otherwise requires, “Northwest Biotherapeutics,” the “company,” “we,” “us,” “our” and similar names refer to Northwest Biotherapeutics, Inc.

PROSPECTUS SUMMARY

This summary highlights information contained elsewhere in this prospectus. Because it is a summary, it might not contain all of the information that is important to you. Accordingly, you are urged to carefully review this prospectus in its entirety, including “Risk Factors” beginning on page 4 and our financial statements and related notes thereto incorporated by reference herein, before making an investment decision.

Business Overview

We are a development stage biotechnology company focused on developing immunotherapy products to treat cancers more effectively than current treatments, without toxicities of the kind associated with chemotherapies, and, through a proprietary batch manufacturing process, on a cost-effective affordable basis initially in both the United States and Europe (the two largest medical markets in the world).

We have developed a platform technology, DCVax, which uses activated dendritic cells to mobilize a patient's own immune system to attack their cancer. The DCVax technology is expected to be applicable to most cancers, and is embodied in several complementary product lines. One of the product lines (DCVax-L) is designed to cover all solid tumor cancers in which the tumors can be surgically removed. Another product line (DCVax-Direct) is designed for all solid tumor cancers which are considered inoperable and cannot be surgically removed. The broad applicability of DCVax to many cancers provides multiple opportunities for commercialization and partnering.

After more than a decade of pre-clinical and clinical development, the DCVax technology has reached late stage development for two different cancers (brain and prostate), with a Phase III clinical trial in glioblastoma multiforme, or GBM, brain cancer currently under way, and a Phase III clinical trial in prostate cancer which was previously cleared to proceed by the U.S. Food and Drug Administration, or FDA, which we anticipate will proceed when we secure a partner. We have also completed a small early stage trial in metastatic ovarian cancer, and we have received clearance from the FDA for early stage trials in multiple other diverse cancers.

In the Phase I/II trials which formed the foundation for reaching these late stage Phase III trials, the clinical results with DCVax were striking. DCVax treatment delayed disease progression and extended survival by years, rather than weeks or months as is typical with cancer drugs. In addition, DCVax was non-toxic: no serious adverse events related to the treatment were seen. These clinical results (both the efficacy and the lack of toxicity) are consistent with a large and growing body of scientific literature and clinical experience, relating to the underlying biology involved.

As of January 24, 2013, our Phase III clinical trial in GBM is being conducted at 41 sites across the United States. Due to the expansion of the trial in the U.S., and the patient flow in the trial, we are amending our agreement with Cognate BioServices, our contract manufacturer, to double the amount of manufacturing capacity for DCVax.

The Phase III GBM trial is also progressing in Europe. On August 23, 2012, we announced that we received approval from the Medicines and Healthcare Products Regulatory Authority in the United Kingdom to proceed with our Phase III clinical trial in GBM in the U.K., and 4 major medical centers in the U.K. are preparing to proceed with the trial. On July 25, 2012, we announced that manufacturing certification has been received from the German regulatory authorities, which is the first step towards implementation of the Phase III trial in Germany. As of January 24, 2013, 24 clinical centers are in varying stages of preparations as trial sites in Germany. We have accelerated and strengthened our programs in Europe by partnering with large, prominent institutions, including the Fraunhofer Institute in Germany and Kings College Hospital in the U.K.

Our DCVax immunotherapies are based on a platform technology involving dendritic cells, the master cells of the immune system, and are designed to reinvigorate and educate the immune system to attack cancers. The dendritic cells are able to mobilize all parts of the immune system, including T cells, B cells and antibodies, natural killer cells and many others. Mobilizing the entire immune system provides a broader attack on the cancer than mobilizing just a particular component, such as T cells alone, or a particular antibody alone. Likewise, our DCVax technology is designed to attack the full set of biomarkers, or antigens on a patient’s cancer, rather than just a particular selected target or several targets. Clinical experience indicates that when just one or a few biomarkers on a cancer are targeted by a drug or other treatment, sooner

or later the cancer usually develops a way around that drug, and the drug stops working. We believe that mobilizing all agents of the immune system, and targeting all biomarkers on the patient’s cancer, contributes to the effectiveness of DCVax.

We believe that the market potential of this technology is particularly large because the DCVax products are expected to be applicable to most cancers. We believe that the market potential is also enhanced by our two-continent strategy. By conducting our Phase III clinical trial in GBM on an international basis, with trial sites in both the United States and Europe, we believe we are positioned to potentially apply for product approval in both markets.

Recent Developments

In August 2012, our Board and a majority of our stockholders approved an amendment to our Amended and Restated 2007 Stock Option Plan providing that, on an ongoing basis, effective January 1 each year, the aggregate number of shares of common stock that are available for issuance under the plan shall automatically be increased by such number of shares as is sufficient to cause the option pool to equal twenty percent (20%) of our issued and outstanding common stock at such time.

On September 25, 2012, we effected a 1-for-16 reverse stock split of our issued and outstanding common stock. In addition, we filed an amendment to our certificate of incorporation increasing our authorized shares of preferred stock from 20,000,000 to 40,000,000.

In December 2012, we retired $34.6 million in aggregate amount of convertible notes, notes and payables by entering into Conversion Agreements with our non-affiliated and affiliated note holders and creditors, including certain of our directors and executive officers. This aggregate debt amount was converted into 9,615,177 common shares and warrants exercisable for 4,807,584 shares of common stock. The warrants have an exercise period of five years from the date of issuance and an exercise price of $6.40 per share.

Corporate Information

We were formed in 1996 and incorporated in Delaware in July 1998. Our principal executive offices are located in Bethesda, Maryland, and our telephone number is (240) 497-9024. Our website address is www.nwbio.com. The information on our website is not part of this prospectus. We have included our website address as a factual reference and do not intend it to be an active link to our website.

RISK FACTORS

Investing in our securities involves risk. The prospectus supplement applicable to each offering of our securities will contain a discussion of the risks applicable to an investment in our company. Prior to making a decision about investing in our securities, you should carefully consider the specific factors discussed below and under the heading “Risk Factors” in the applicable prospectus supplement, together with all of the other information contained or incorporated by reference in the prospectus supplement or appearing or incorporated by reference in this prospectus. You should also consider the risks, uncertainties and assumptions discussed under the heading “Risk Factors” included in our most recent annual report on Form 10-K, as revised or supplemented by our most recent quarterly report on Form 10-Q, each of which are on file with the SEC and are incorporated herein by reference, and which may be amended, supplemented or superseded from time to time by other reports we file with the SEC in the future.

Risks Related to our Business

We will need to raise substantial funds, on an ongoing basis, for general corporate purposes and operations, including our clinical trials. Such funding may not be available or may not be available on attractive terms.

As of September 30, 2012, we had approximately $0.1 million of cash on hand. In December, 2012, we received gross proceeds of approximately $14 million in a public offering of our shares and warrants. Also, in December 2012, we retired $34.6 million in aggregate amount of convertible notes, notes and payables by entering into Conversion Agreements with our non-affiliated and affiliated note holders and creditors, including certain of our directors and executive officers. This aggregate debt amount was converted into 9,615,777 common shares and warrants exercisable for 4,807,584 shares of common stock.

We will need substantial additional funding, on an ongoing basis, in order to continue execution of our clinical trials, to move our product candidates towards commercialization, to continue prosecution and maintenance of our large patent portfolio, to continue development and optimization of our manufacturing and distribution arrangements, and for other corporate purposes. Any financing, if available, may include restrictive covenants and provisions that could limit our ability to take certain actions, preference provisions for the investors, and/or discounts, warrants or other incentives. Any financing will involve issuance of equity and/or debt, and such issuances will be dilutive to existing shareholders. There can be no assurance that we will be able to complete any of the financings, or that the terms for such financings will be attractive. If we are unable to obtain additional funds on a timely basis or on acceptable terms, we may be required to curtail or cease some or all of our operations at any time.

We are likely to continue to incur substantial losses, and may never achieve profitability.

We have incurred net losses every year since our formation in March 1996, and had a deficit accumulated during the development stage of approximately $251.8 million and $288.6 million as of December 31, 2011 and September 30, 2012, respectively, of which $117.2 million was cash expenditures and $134.6 million was non-cash accounting measures as of December 31, 2011 and $131.7 million was cash expenditures and $156.9 million was non-cash accounting measures as of September 30, 2012. We expect that these losses will continue, and we anticipate negative cash flows from operations for the foreseeable future. We may never achieve or sustain profitability.

Our auditors have issued a “going concern” audit opinion.

Our independent auditors have indicated, in their report on our December 31, 2011 financial statements, that there is substantial doubt about our ability to continue as a going concern. A “going concern” opinion indicates that the financial statements have been prepared assuming we will continue as a going concern and do not include any adjustments to reflect the possible future effects on the recoverability and classification of assets, or the amounts and classification of liabilities, that may result if we do not continue as a going concern. Therefore, you should not rely on our consolidated balance sheet as an indication of the amount of proceeds that would be available to satisfy claims of creditors, and potentially be available for distribution to shareholders, in the event of liquidation.

As a development stage company with a novel technology and unproven business strategy, our limited history of operations makes an evaluation of our business and prospects difficult.

We will need to expand our management and technical personnel as our operations progress, and we may not be able to recruit such additional personnel and/or retain existing personnel.

As of December 31, 2012, we employ eight (8) full-time employees. The rest of our personnel are retained on a consulting or contractor basis. Biotech companies would typically have a larger number of employees by the time they reach late stage clinical trials. Such trials require extensive management activities and skill sets, including scientific, medical, regulatory (for FDA and foreign regulatory counterparts), manufacturing, distribution and logistics, site management, business, financial, legal, public relations outreach to both the patient community and physician community, intellectual property, administrative, regulatory (SEC), investor relations and other.

In order to fully perform all these diverse functions, with late stage trials under way at many sites across the U.S. and soon in Europe, we will need to expand our management and technical personnel. However, the pool of such personnel with expertise and experience with living cell products, such as our DCVax immune cell product, is very limited. In addition, we are a small company with limited resources, our business prospects are uncertain and our stock price is volatile. For some or all of such reasons, we may not be able to recruit all the management and technical personnel we need, and/or we may not be able to retain all of our existing personnel. In such event, we may have to continue our operations with a smaller than usual team of personnel, and our business and financial results may suffer.

We rely at present on third-party contract manufacturers. As a result, we may be at risk for capacity limitations and/or supply disruptions.

We currently rely upon Cognate BioServices, Inc., or Cognate, to produce all of our DCVax product in the U.S., and to supervise the production of our DCVax product candidates outside the U.S. The majority owner of Cognate is Toucan Capital, one of our major stockholders, and its affiliates. We have an agreement in place with Cognate pursuant to which Cognate has agreed to provide manufacturing and other services for the next five years, in connection with our Phase III clinical trial of DCVax -L in brain cancer, and other programs. The agreement requires us to make certain minimum monthly payments to Cognate in order to have dedicated manufacturing capacity available for our products, irrespective of whether we actually order any DCVax products. The agreement also specifies the amounts we must pay for Cognate's actual manufacturing of DCVax for patients.

We have entered into an agreement with King’s College London to manufacture DCVax for our clinical trial and our compassionate use cases. Cognate will manage and supervise the processing in London. In addition, our partner, Fraunhofer, has received approval and certification from the regional and national regulatory agencies in Germany for the manufacture of DCVax for GBM. We anticipate that the manufacturing facilities in the U.K. and Germany will be able to supply DCVax products for anywhere in Europe (and to the U.S., if needed), however this may not turn out to be feasible, for regulatory, operational and/or logistical reasons.

disasters or otherwise, changes in FDA regulatory requirements or standards that require modifications to our manufacturing processes, action by the FDA or European regulators, or by us that results in the halting or slowdown of production of components or finished products due to regulatory issues, our manufacturers going out of business or failing to produce product as contractually required, and/or other similar factors. Because manufacturing processes for our DCVax product candidates are highly complex, require specialized facilities and personnel that are not widely available in the industry, involve equipment and training with long lead times, and are subject to lengthy regulatory approval processes, alternative qualified production capacity may not be available on a timely basis or at all. Difficulties, delays or interruptions in the manufacturing and supply of our DCVax product candidates could require us to stop enrolling additional new patients into our trial, and/or require us to stop the trial or other program, increase our costs, damage our reputation and, if our product candidates are approved for sale, cause us to lose revenue or market share if our manufacturers are unable to timely meet market demands.

The manufacturing of our product candidates will have to be greatly scaled up for commercialization, and neither we nor other parties in the industry have experience with such scale-up.

As is the case with any clinical trial, our Phase III clinical trial of DCVax-L for GBM involves a number of patients that is a small fraction of the number of potential patients for whom DCVax-L may be applicable in the commercial market. The same will be true of our other clinical programs with our other DCVax product candidates. If our DCVax-L, and/or other DCVax product candidates, are approved for commercial sale, it will be necessary to greatly scale up the volume of manufacturing, far above its level for the trials. Neither we nor our contract manufacturers have experience with such scale-up. In addition, there are virtually no consultants or advisors in the industry who have such experience and can provide guidance or assistance, because active immune therapies such as DCVax are a fundamentally new category of product in two major ways: these active immune therapy products consist of living cells, not chemical or biologic compounds, and the products are personalized. To our knowledge, no such products have successfully completed the necessary scale-up for commercialization without material difficulties. For example, Dendreon has encountered substantial difficulties trying to scale up the manufacturing of its Provenge product for commercialization.

The necessary specialized facilities, equipment and personnel may not be available or obtainable for the scale-up of manufacturing of our product candidates.

The manufacture of living cells requires specialized facilities, equipment and personnel which are entirely different than what is required for manufacturing of chemical or biologic compounds. Scaling up the manufacturing of living cell products to volume levels required for commercialization will require enormous amounts of these specialized facilities, equipment and personnel — especially where, as in the case of our DCVax product candidates, the product is personalized and must be made for each patient individually. Since living cell products are so new, and have barely begun to reach commercialization, the supply of the specialized facilities, equipment and personnel needed for them has not yet developed. It may not be possible for us or our manufacturers to obtain all of the specialized facilities, equipment and personnel needed for commercialization of our DCVax product candidates. This could delay or halt our commercialization.

Our technology is novel, involves complex immune system elements, and may not prove to be effective.

Data already obtained, or in the future obtained, from pre-clinical studies and clinical trials do not necessarily predict the results that will be obtained from later pre-clinical studies and clinical trials. Over the course of several decades, there have been many different immune therapy product designs — and many product failures and company failures. To our knowledge, to date, only one active immune therapy, Provenge, has been approved by the FDA. The human immune system is complex, with many diverse elements, and the state of scientific understanding of the immune system is still limited. Some immune therapies previously developed by other parties showed surprising and unexpected toxicity in clinical trials. Other immune therapies developed by other parties delivered promising results in early clinical trials, but failed in later stage clinical trials. To date, we have only completed early stage trials in limited numbers of patients. Although the results of those trials were quite positive, those results may not be achieved in our later stage clinical trials, such as the 300-patient Phase III trial we are now conducting for GBM, and our product candidates may not ultimately be found to be effective.

Clinical trials for our product candidates are expensive and time consuming, and their outcome is uncertain.

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the duration of the clinical trial;

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the number of sites included in the trials;

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the countries in which the trial is conducted;

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the length of time required and ability to enroll eligible patients;

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the number of patients that participate in the trials;

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the number of doses that patients receive;

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the drop-out or discontinuation rates of patients;

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per patient trial costs;

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third party contractors failing to comply with regulatory requirements or meet their contractual obligations to us in a timely manner;

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our final product candidates having different properties in humans than in lab testing;

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the need to suspect or terminate our clinical trials;

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insufficient or inadequate supply of quality of necessary materials to conduct our trials;

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potential additional safety monitoring, or other conditions required by FDA or comparable foreign regulatory authorities regarding the scope or design of our clinical trials, or other studies requested by regulatory agencies;

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problems engaging IRBs to oversee trials or in obtaining and maintaining IRB approval of studies;

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the duration of patient follow-up;

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the efficacy and safety profile of a product candidate;

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the costs and timing of obtaining regulatory approvals; and

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the costs involved in enforcing or defending patent claims or other intellectual property rights.

We may be required to suspend or discontinue clinical trials due to unexpected side effects or other safety risks that could preclude approval of our product candidates.

We have limited experience in conducting and managing clinical trials.

We rely on third parties to assist us, on a contract services basis, in managing and monitoring all of our clinical trials. We do not have experience conducting late stage clinical trials ourselves without third party service firms, other than our current Phase III trial, nor do we have experience in supervising such third parties in managing late stage, multi-hundred patient clinical trials, other than our current Phase III trial. Our lack of experience and/or our reliance on these third party service firms may result in delays or failure to complete these trials successfully and on time. If the third parties fail to perform, we may not be able to find sufficient alternative suppliers of those services in a reasonable time period, or on commercially reasonable terms, if at all. If we were unable to obtain alternative suppliers of such services, we might be forced to delay, suspend or stop our 300-patient Phase III clinical trial of DCVax-L for GBM.

Multiple late stage clinical trials of DCVax-L for GBM, our lead product, may be required before we can obtain regulatory approval.

Typically, companies conduct multiple late stage clinical trials of their product candidates before seeking product approval. Our current Phase III 300-patient clinical trial of DCVax-L for GBM is our first late stage trial. We may be required to conduct additional late stage trials with DCVax-L for GBM before we can obtain product approval. This would substantially delay our commercialization. There is also some possibility that changes requested by the FDA could complicate the application process for product approval. In addition, a number of products are under development for brain cancer and at least one has recently been approved in the U.S.. It is possible that the standard of care for brain cancer could change while our Phase III trial is still under way. This could necessitate further clinical trials with our DCVax-L product candidate for brain cancer.

Changes in manufacturing methods for DCVax-L could require us to conduct equivalency studies and/or additional clinical trials.

We may not receive regulatory approvals for our product candidates or there may be a delay in obtaining such approvals.

Our products and our ongoing development activities are subject to regulation by regulatory authorities in the countries in which we or our collaborators and distributors wish to test, manufacture or market our products. For instance, the FDA will regulate the product in the U.S. and equivalent authorities, such as the European Medicines Agency, or EMA, will regulate in Europe. Regulatory approval by these authorities will be subject to the evaluation of data relating to the quality, efficacy and safety of the product for its proposed use, and there can be no assurance that the regulatory authorities will find our data sufficient to support product approval of DCVax-L.

The time required to obtain regulatory approval varies between countries. In the U.S., for products without “Fast Track” status, it can take up to eighteen (18) months after submission of an application for product approval to receive the FDA's decision. Even with Fast Track status, FDA review and decision can

take up to twelve (12) months. At present, we do not have Fast Track status for our lead product, DCVax-L for GBM. We plan to apply for Fast Track status, but there can be no assurance that FDA will grant us such status for DCVax-L.

We may fail to comply with regulatory requirements.

Regulatory approval of our product candidates may be withdrawn at any time.

The manufacturer and manufacturing facilities we use to make any of our products will also be subject to periodic review and inspection by the FDA or EMA, as applicable. The discovery of any new or previously unknown problems with the product, manufacturer or facility may result in restrictions on the product or manufacturer or facility, including withdrawal of the product from the market. We will continue to be subject to the FDA or EMA requirements, as applicable, governing the labeling, packaging, storage, advertising, promotion, recordkeeping, and submission of safety and other post-market information for all of our product candidates, even those that the FDA or EMA, as applicable, had approved. If we fail to comply with applicable continuing regulatory requirements, we may be subject to fines, suspension or withdrawal of regulatory approval, product recalls and seizures, operating restrictions and other adverse consequences.

Our product candidates will require a different distribution model than conventional therapeutic products, and this may impede commercialization of our product candidates.

Our DCVax product candidates consist of living human immune cells. Such products are entirely different from chemical or biologic drugs, and require different handling, distribution and delivery than chemical or biologic drugs. One crucial difference is that our DCVax products must remain frozen throughout the distribution and delivery process, until the time of administration to the patient, and cannot be handled at room temperature. In addition, our DCVax product candidates are personalized and they involve ongoing treatment cycles over several years for each patient. Each product shipment for each patient must be tracked and managed individually. For all of these reasons, among others, we will not be able to simply use the distribution networks and processes that already exist for conventional drugs. It may take time for shipping companies, hospitals, pharmacies and physicians to adapt to the requirements for handling, distribution and delivery of these products, which may adversely affect our commercialization.

Our product candidates will require different marketing and sales methods and personnel than conventional therapeutic products. Also, we lack sales and marketing experience. These factors may result in significant difficulties in commercializing our product candidates.

The commercial success of any of our product candidates will depend upon the strength of our sales and marketing efforts. We do not have a marketing or sales force and have no experience in marketing or sales of products like our lead product, DCVax-L for GBM. To fully commercialize our product candidates, we will need to recruit and train marketing staff and a sales force with technical expertise and ability to manage the distribution of our DCVax-L for GBM. As an alternative, we could seek assistance from a corporate partner or a third party services firm with a large distribution system and a large direct sales force. However, since our DCVax living cell, immune therapy products are a fundamentally new and different type of product than are on the market today, we would still have to train such partner’s or such services firms’ personnel about our products, and would have to make changes in their distribution processes and systems to handle our products. We may be unable to recruit and train effective sales and marketing forces or our own, or of a partner or a services firm, and/or doing so may be more costly and difficult than anticipated. Such factors may result in significant difficulties in commercializing our product candidates, and we may be unable to generate significant revenues.

We may not obtain or maintain the benefits associated with orphan drug status, including market exclusivity.

Although our lead product, DCVax-L for GBM, has been granted orphan drug status in both the United States and the European Union, or EU, we may not receive the benefits associated with orphan drug designation (including the benefit providing for market exclusivity for a number of years). This may result from a failure to maintain orphan drug status, or result from a competing product reaching the market that has an orphan designation for the same disease indication. Under U.S. and EU rules for orphan drugs, if such a competing product reaches the market before ours does, the competing product could potentially obtain a scope of market exclusivity that limits or precludes our product from being sold in the U.S. for seven years or from being sold in the EU for ten years. Also, in the EU, even after orphan status has been granted, that status is re-examined shortly prior to the product receiving any regulatory approval. The EMA must be satisfied that there is evidence that the product offers a significant benefit relative to existing therapies, in order for the therapeutic product to maintain its orphan drug status. Accordingly, our product candidates will have to re-qualify for orphan drug status prior to any potential product approval in the EU.

The availability and amount of potential reimbursement for our product candidates by government and private payers is uncertain and may be delayed and/or inadequate.

Reimbursement agencies in Europe can be even more conservative than CMS in the U.S.. A number of cancer drugs which have been approved for reimbursement in the U.S. have not been approved for reimbursement in certain European countries, and/or the level of reimbursement approved in Europe is lower than in the U.S.

medical products, as the majority of our costs are incurred up front, when the manufacturing of the personalized product is done. Our atypical cost structure may not be accommodated in any reimbursement for our products. If we are unable to obtain adequate levels of reimbursement, our ability to successfully market and sell our product candidates will be adversely affected.

Competition in the biotechnology and biopharmaceutical industry is intense and most of our competitors have substantially greater resources than we do.

The biotechnology and biopharmaceutical industries are characterized by rapidly advancing technologies, intense competition and a strong emphasis on proprietary products. Several companies, such as Dendreon, Celldex Therapeutics, Inc., Ark Therapeutics plc, Oxford Biomedica plc, Argos Therapeutics, Inc., Agenus, Inc., Prima Biomed, Ltd., Avax Technologies, Inc., Immunocellular Therapeutics, Ltd., Bavarian Nordic, Bellicum Pharmaceuticals, and others are actively involved in the research and development of immune therapies or cell-based therapies for cancer. In addition, other novel technologies for cancer are under development, such as the electro-therapy device of NovoCure. Of these companies, only one has obtained approval of such an immune therapy: Dendreon (for its Provenge treatment of prostate cancer). Additionally, several companies, such as Medarex, Inc., Amgen, Inc., Agensys, Inc., and Genentech, Inc., are actively involved in the research and development of monoclonal antibody-based cancer therapies. Currently, at least seven antibody-based products are approved for commercial sale for cancer therapy, and a large number of additional ones are under development. Genentech is also engaged in several Phase III clinical trials for additional antibody-based therapeutics for a variety of cancers, and several other companies are in early stage clinical trials for such products. Many other third parties compete with us in developing alternative therapies to treat cancer, including: biopharmaceutical companies; biotechnology companies; pharmaceutical companies; academic institutions; and other research organizations, as well as some medical device companies (e.g., NovoCure and MagForce Nano Technologies AG).

Competing generic medicinal products may be approved.

In the EU, there exists a process for approval of generic biological medicinal products once patent protection and other forms of data and market exclusivity have expired. Arrangements for approval of generic biologics products exist and are under consideration in the U.S., as well. Other jurisdictions are considering adopting legislation that would allow the approval of generic biological medicinal products. If generic medicinal products are approved, competition from such products may substantially reduce sales of our products.

We may be exposed to potential product liability claims, and our existing insurance may not cover these claims in whole or in part. In addition, insurance against such claims may not be available to us on reasonable terms in the future, if at all.

Our intellectual property rights may be overturned, narrowed or blocked, and may not provide sufficient commercial protection for our product candidates, or third parties may infringe upon our intellectual property.

Patent laws afford only limited protection and may not protect our rights to the extent necessary to sustain any competitive advantage we may have. In addition, the laws of some foreign countries do not protect proprietary rights to the same extent as the laws of the United States, and we may encounter significant problems in protecting our proprietary rights in those countries. Moreover patents and patent applications relating to living cell products are relatively new, involve complex factual and legal issues, and are largely untested in litigation — and as a result, are uncertain. Third parties may challenge our existing patents, and such challenges could result in overturning or narrowing some of our patents. Even if our patents are not challenged, third parties could assert that their patents block some or all of our patents

As of December 31, 2012, we have over 100 issued patents (7 in the U.S.) and more than 90 pending patent applications related to our product candidates, and related processes such as manufacturing processes.

The issued patents expire at various dates from 2015 to 2026. Our issued patents may be challenged, and such challenges may result in reductions in scope or invalidations. Our pending patent applications may not result in issued patents. Moreover, our patents and patent applications may not be sufficiently broad to prevent others from using substantially similar technologies or from developing competing products. We also face the risk that others may independently develop similar or alternative technologies, or design around our patented technologies.

We may be exposed to claims or lawsuits — with or without merit — on various subjects, including that our products infringe patents or other proprietary rights of other parties.

In addition, because patents can take many years to issue, and patent applications are not published until up to eighteen months after they are filed, there may be currently pending applications, unknown to us, which may later result in issued patents that our products may inadvertently infringe. There could also be existing patents of which we are not aware that one or more of our products may inadvertently infringe.

DCVax is our only technology in clinical development.

Collaborations play an important role in our business, and could be vulnerable to competition or termination.

operations or the commercial feasibility of our personalized DCVax product candidates, these third parties may decide not to conduct business with us or may conduct business with us on terms that are less favorable than those customarily extended by them. If either of these events occurs, our business could suffer significantly.

Our business could be adversely affected by new legislation and/or product related issues.

Our business could be adversely affected by animal rights activists.

Our business activities have involved animal testing, as such testing is required before new medical products can be tested in clinical trials in patients. Animal testing has been the subject of controversy and adverse publicity. Some organizations and individuals have attempted to stop animal testing by pressing for legislation and regulation in these areas. To the extent that the activities of such groups are successful, our business could be adversely affected. Negative publicity about us, our pre-clinical trials and our product candidates could also adversely affect our business.

Risks Related to our Common Stock

The market price of our common stock may be volatile and adversely affected by several factors.

Toucan Capital and its affiliates are the principal holders of our shares of common stock, and this concentration of ownership may have a negative effect on the market price of our common stock.

As of December 31, 2012, Toucan Capital and its affiliates (including Cognate BioServices, Toucan Partners and Linda Powers, who also serves as our Chief Executive Officer and Chairperson of the Board of Directors), collectively, owned an aggregate of 10,958,287 shares of our common stock, representing approximately 48.0 percent of our issued and outstanding common stock. This concentration of ownership may adversely affect the trading price of our common stock because investors may perceive disadvantages in owning stock of companies with controlling stockholders. Toucan Capital and its affiliates have the ability to exert substantial influence over all matters requiring approval by our stockholders, including the election and removal of directors and any proposed merger, consolidation or sale of all or substantially all of our assets. This influence could have the effect of delaying, deferring or preventing a change in control, or impeding a merger or consolidation, takeover or other business combination that could be favorable to investors.

The requirements of the Sarbanes-Oxley Act of 2002 and other U.S. securities laws impose substantial costs, and may drain our resources and distract our management.

Our management and our independent auditor have identified internal control deficiencies, which our management and our independent auditor believe constitute material weaknesses.

In connection with the preparation of our financial statements for the year ended December 31, 2011, and prior years, our management and our independent auditor identified certain internal control deficiencies that, in the aggregate, represent material weaknesses, including:

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lack of a sufficient number of independent directors on our audit committee;

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lack of a financial expert on our audit committee;

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insufficient segregation of duties in our finance and accounting function due to limited personnel;

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lack of controls in place to ensure that all material developments impacting the financial statements are reflected;

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lack of oversight and review of financial reporting;

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lack of internal accounting technical expertise;

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lack of preparation and review and verification of internally developed documentation; and

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lack of executed agreements for significant contracts.

As part of our independent auditors’ communications with our audit committee with respect to audit procedures for the year ended December 31, 2011, our independent auditors informed the audit committee that these deficiencies constituted material weaknesses, as defined by Auditing Standard No. 5, “An Audit of Internal Control Over Financial Reporting that is Integrated with an Audit of Financial Statements and Related Independence Rule and Conforming Amendments,” established by the Public Company Accounting Oversight Board, or PCAOB. We have begun taking appropriate and reasonable steps, and will continue and complete such steps in due course, to make the necessary improvements to address these deficiencies, but the timing of such steps is uncertain and the availability of funding and resources for such steps are also uncertain. Our ability to attract qualified individuals to serve on our Board and to take on key management roles within the Company is also uncertain. Our failure to successfully complete the remedies of the existing weaknesses could lead to heightened risk for financial reporting mistakes and irregularities, and/or lead to a loss of public confidence in our internal controls that could have a negative effect on the market price of our common stock.

We do not intend to pay any cash dividends in the foreseeable future and, therefore, any return on your investment in our common stock must come from increases in the market price of our common stock.

Our certificate of incorporation and bylaws, our shareholder rights plan and Delaware law have anti-takeover provisions that could discourage, delay or prevent a change in control, which may cause our stock price to decline.

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provide the Board of Directors with the ability to alter the bylaws without stockholder approval;

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establish staggered terms for board members;

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place limitations on the removal of directors; and

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provide that vacancies on the Board of Directors may be filled by a majority of directors in office, although less than a quorum.

These provisions are expected to discourage certain types of coercive takeover practices and inadequate takeover bids and to encourage persons seeking to acquire control of our company to first negotiate with its board. These provisions may delay or prevent someone from acquiring or merging with us, which may cause the market price of our common stock to decline.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and any accompanying prospectus supplement, including the documents that we incorporate by reference, contains forward-looking statements. Such forward-looking statements include those that express plans, anticipation, intent, contingency, goals, targets or future development and/or otherwise are not statements of historical fact. These forward-looking statements are based on our current expectations and projections about future events, and they are subject to risks and uncertainties (known and unknown) that could cause actual results and developments to differ materially from those expressed or implied in such statements, including the following, among others:

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our ability to raise funds for general corporate purposes and operations, including our clinical trials;

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the commercial feasibility and success of our technology;

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our ability to recruit qualified management and technical personnel;

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our ability to scale up the manufacturing of our product candidates for commercialization;

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the success of our clinical trials;

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our ability to obtain and maintain required regulatory approvals for our products; and

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the other factors discussed in the “Risk Factors” section and elsewhere in this prospectus.

In some cases, you can identify forward-looking statements by terminology, such as “expects,” “anticipates,” “intends,” “estimates,” “plans,” “believes,” “seeks,” “may,” “should”, “could” or the negative of such terms or other similar expressions. Accordingly, these statements involve estimates, assumptions and uncertainties that could cause actual results to differ materially from those expressed in them. Any forward-looking statements are qualified in their entirety by reference to the factors discussed throughout this prospectus.

You should read this prospectus and any accompanying prospectus supplement and the documents that we reference herein and therein and have filed as exhibits to the registration statement, of which this prospectus is part, completely and with the understanding that our actual future results may be materially different from what we expect. You should assume that the information appearing in this prospectus and any accompanying prospectus is accurate as of the date on the front cover of this prospectus or such prospectus supplement only. Because the risk factors referred to above could cause actual results or outcomes to differ materially from those expressed in any forward-looking statements made by us or on our behalf, you should not place undue reliance on any forward-looking statements. Further, any forward-looking statement speaks only as of the date on which it is made, and we undertake no obligation to update any forward-looking statement to reflect events or circumstances after the date on which the statement is made or to reflect the occurrence of unanticipated events. New factors emerge from time to time, and it is not possible for us to predict which factors will arise. In addition, we cannot assess the impact of each factor on our business or the extent to which any factor, or combination of factors, may cause actual results to differ materially from those contained in any forward-looking statements. We qualify all of the information presented in this prospectus and any accompanying prospectus supplement, and particularly our forward-looking statements, by these cautionary statements.

USE OF PROCEEDS

Except as otherwise provided in the applicable prospectus supplement, we intend to use the net proceeds from the sale of the securities offered by this prospectus for general corporate purposes, which may include working capital, capital expenditures, research and development expenditures, regulatory affairs expenditures, clinical trial expenditures, acquisitions of new technologies and investments, and the repayment, refinancing, redemption or repurchase of future indebtedness or capital stock.

The intended application of proceeds from the sale of any particular offering of securities using this prospectus will be described in the accompanying prospectus supplement relating to such offering. The precise amount and timing of the application of these proceeds will depend on our funding requirements and the availability and costs of other funds.

RATIO OF EARNINGS TO FIXED CHARGES

If we offer debt securities under this prospectus, then we will, if required at that time, provide a ratio of earnings to fixed charges in the applicable prospectus supplement for such offering.

THE SECURITIES WE MAY OFFER

The descriptions of the securities contained in this prospectus, together with the applicable prospectus supplements, summarize all the material terms and provisions of the various types of securities that we may offer. We will describe in the applicable prospectus supplement relating to any securities the particular terms of the securities offered by that prospectus supplement. If we indicate in the applicable prospectus supplement, the terms of the securities may differ from the terms we have summarized below. We will also include in the prospectus supplement information, where applicable, about material United States federal income tax considerations relating to the securities, and the securities exchange, if any, on which the securities will be listed.

We may sell from time to time, in one or more offerings:

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shares of our common stock;

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shares of our preferred stock;

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debt securities;

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warrants to purchase any of the securities listed above; and/or

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units consisting of any of the securities listed above.

The terms of any securities we offer will be determined at the time of sale. We may issue securities that are exchangeable for or convertible into common stock or any of the other securities that may be sold under this prospectus. When particular securities are offered, a supplement to this prospectus will be filed with the SEC, which will describe the terms of the offering and sale of the offered securities.

DESCRIPTION OF CAPITAL STOCK

General

The following description of common stock and preferred stock, together with the additional information we include in any applicable prospectus supplements, summarizes the material terms and provisions of the common stock and preferred stock that we may offer under this prospectus but is not complete. For the complete terms of our common stock and preferred stock, please refer to our certificate of incorporation, as amended, (the “Certificate of Incorporation”) which may be further amended from time to time, any certificates of designation for our preferred stock, and our amended and restated bylaws, as amended from time to time (the “Bylaws”). Delaware General Corporation Law (“DGCL”) may also affect the terms of these securities. While the terms we have summarized below will apply generally to any future common stock or preferred stock that we may offer, we will describe the particular terms of any series of these securities in more detail in the applicable prospectus supplement. If we so indicate in a prospectus supplement, the terms of any common stock or preferred stock we offer under that prospectus supplement may differ from the terms we describe below.

Our Seventh Amended and Restated Certificate of Incorporation, as amended, authorizes the issuance of 450,000,000 shares of common stock, $0.001 par value per share and 40,000,000 shares of preferred stock, $0.001 par value per share. As of January 24, 2013, we had 26,370,283 shares of common stock outstanding and no shares of preferred stock outstanding.

The following summary of certain provisions of our common stock and preferred stock does not purport to be complete. You should refer to our Seventh Amended and Restated Certificate of Incorporation, as amended and our Third Amended and Restated Bylaws, as amended. The summary below is also qualified by provisions of applicable law.

Common Stock

Holders of shares of common stock are entitled to one vote for each share on all matters to be voted on by the stockholders. Holders of common stock have no cumulative voting rights. Accordingly, the holders of in excess of 50% of the aggregate number of shares of common stock outstanding will be able to elect all of our directors and to approve or disapprove any other matter submitted to a vote of all stockholders.

No shareholder has any preemptive right or other similar right to purchase or subscribe for any additional securities issued by us. No shareholder has any right to convert the common stock into other securities. No shares of common stock are subject to redemption or any sinking fund provisions. All the outstanding shares of our common stock are fully paid and non-assessable. There is no outstanding preferred stock, and no outstanding securities convertible into or exercisable for preferred stock. Our common stock holders are entitled to dividends when, as and if declared by the Board from funds legally available therefor, although we do not anticipate declaring or paying any cash dividends on the common stock in the foreseeable future. Upon liquidation, the common stock holders are entitled to a pro-rata share in any distribution to shareholders.

Preferred Stock

Our board of directors has the authority, without further action by the stockholders, to issue up to 40,000,000 shares of preferred stock in one or more series and to fix the rights, preferences, privileges and restrictions thereof, including dividend rights, conversion rights, voting rights, terms of redemption, liquidation preferences, sinking fund terms and the number of shares constituting any series or the designation of such series, without any further vote or action by our stockholders. As of the date of this prospectus, no shares of preferred stock were outstanding. The issuance of preferred stock could adversely affect the voting power of holders of common stock and the likelihood that such holders will receive dividend payments and payments upon liquidation and could have the effect of delaying, deferring or preventing a change in control of our company.

We will fix the rights, preferences, privileges and restrictions of the preferred stock of each series in the certificate of designation relating to that series. We will file as an exhibit to the registration statement of which this prospectus is a part, or will incorporate by reference from reports that we file with the SEC, the form of any certificate of designation that describes the terms of the series of preferred stock we are offering before the issuance of the related series of preferred stock. This description will include any or all of the following, as required:

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the title and stated value;

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the number of shares we are offering;

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the liquidation preference per share;

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the purchase price;

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the dividend rate, period and payment date and method of calculation for dividends;

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whether dividends will be cumulative or non-cumulative and, if cumulative, the date from which dividends will accumulate;

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the procedures for any auction and remarketing, if any;

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the provisions for a sinking fund, if any;

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the provisions for redemption or repurchase, if applicable, and any restrictions on our ability to exercise those redemption and repurchase rights;

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any listing of the preferred stock on any securities exchange or market;

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whether the preferred stock will be convertible into our common stock, and, if applicable, the conversion price, or how it will be calculated, and the conversion period;

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voting rights, if any, of the preferred stock;

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preemptive rights, if any;

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restrictions on transfer, sale or other assignment, if any;

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whether interests in the preferred stock will be represented by depositary shares;

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a discussion of any material or special United States federal income tax considerations applicable to the preferred stock;

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the relative ranking and preferences of the preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs;

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any limitations on issuance of any class or series of preferred stock ranking senior to or on a parity with the series of preferred stock as to dividend rights and rights if we liquidate, dissolve or wind up our affairs; and

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any other specific terms, preferences, rights or limitations of, or restrictions on, the preferred stock.

If we issue shares of preferred stock under this prospectus, the shares will be fully paid and non-assessable.

The DGCL provides that the holders of preferred stock will have the right to vote separately as a class on any proposal involving fundamental changes in the rights of holders of that preferred stock. This right is in addition to any voting rights that may be provided for in the applicable certificate of designation.

Our board of directors may authorize the issuance of preferred stock with voting or conversion rights that could adversely affect the voting power or other rights of the holders of our common stock. Preferred stock could be issued quickly with terms designed to delay or prevent a change in control of our company or make removal of management more difficult. Additionally, the issuance of preferred stock may have the effect of decreasing the market price of our common stock.

Transfer Agent and Registrar

The transfer agent and registrar for our common stock is Computershare Shareowner Services.

Anti-Takeover Effects of Certain Provisions of our Certificate of Incorporation, Bylaws and the DGCL

Certain provisions of DGCL and our Amended and Restated Certificate of Incorporation, as amended and Amended and Restated Bylaws, as amended discussed below may have the effect of making more difficult or discouraging a tender offer, proxy contest or other takeover attempt. These provisions are expected to encourage persons seeking to acquire control of our company to first negotiate with our board of directors. We believe that the benefits of increasing our ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure our company outweigh the disadvantages of discouraging these proposals because negotiation of these proposals could result in an improvement of their terms.

Delaware Anti-takeover Law

We are subject to Section 203 of the DGCL, an anti-takeover law. In general, Section 203 prohibits a publicly held Delaware corporation from engaging in a “business combination” with an “interested stockholder” for a period of three years following the date the person became an interested stockholder, unless:

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the board of directors approves the transaction in which the stockholder became an interested stockholder prior to the date the interested stockholder attained that status;

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when the stockholder became an interested stockholder, he or she owned at least 85% of the voting stock of the corporation outstanding at the time the transaction commenced, excluding shares owned by persons who are directors and also officers and certain shares owned by employee benefits plans; or

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on or subsequent to the date the business combination is approved by the board of directors, the business combination is authorized by the affirmative vote of at least 66 2/3% of the voting stock of the corporation at an annual or special meeting of stockholders.

Generally, a “business combination” includes a merger, asset or stock sale, or other transaction resulting in a financial benefit to the interested stockholder. Generally, an “interested stockholder” is a person who,

together with affiliates and associates, owns, or is an affiliate or associate of the corporation and within three years prior to the determination of interested stockholder status did own, 15% or more of a corporation’s voting stock.

The existence of Section 203 of the DGCL would be expected to have an anti-takeover effect with respect to transactions not approved in advance by our board of directors, including discouraging attempts that might result in a premium over the market price for the shares of our common stock.

Rights Plan

Amended and Restated Certificate of Incorporation and Bylaw Provisions

Our Seventh Amended and Restated Certificate of Incorporation, as amended and bylaws contain provisions that could have the effect of discouraging potential acquisition proposals or making a tender offer or delaying or preventing a change in control, including changes a stockholder might consider favorable. In particular, the certificate of incorporation and bylaws, as applicable, among other things:

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provide a staggered Board of Directions with three classes of directors;

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provide our Board of Directors with the ability to alter its bylaws without stockholder approval; and

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provide that vacancies on our Board of Directors may be filled by a majority of directors in office, although less than a quorum.

Such provisions may have the effect of discouraging a third-party from acquiring us, even if doing so would be beneficial to our stockholders. These provisions are intended to enhance the likelihood of continuity and stability in the composition of our Board of Directors and in the policies formulated by them, and to discourage some types of transactions that may involve an actual or threatened change in control of our company. These provisions are designed to reduce our vulnerability to an unsolicited acquisition proposal and to discourage some tactics that may be used in proxy fights. We believe that the benefits of increased protection of our potential ability to negotiate with the proponent of an unfriendly or unsolicited proposal to acquire or restructure our company outweigh the disadvantages of discouraging such proposals because, among other things, negotiation of such proposals could result in an improvement of their terms.

However, these provisions could have the effect of discouraging others from making tender offers for our shares that could result from actual or rumored takeover attempts. These provisions also may have the effect of preventing changes in our management.

DESCRIPTION OF DEBT SECURITIES

The following description, together with the additional information we include in any applicable prospectus supplement, summarizes the material terms and provisions of any debt securities that we may offer under this prospectus. While the terms we have summarized below will apply generally to any future debt securities we may offer, we will describe the particular terms of any debt securities that we may offer in more detail in the applicable prospectus supplement. The terms of any debt securities we may offer under a prospectus supplement may differ from the terms described below. For any debt securities that we may offer, an indenture (and any relevant supplemental indenture) will contain additional important terms and provisions and will be incorporated by reference as an exhibit to the registration statement that includes this prospectus, or as an exhibit to reports that we file with the SEC and incorporated by reference in this prospectus.

With respect to any debt securities that we issue, we will issue such debt securities under an indenture, which we would enter into with the trustee named in the indenture. Any indenture would be qualified under the Trust Indenture Act of 1939.

With respect to any debt securities that we issue, we will describe in each prospectus supplement the following terms relating to a series of debt securities:

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the title;

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the principal amount being offered, and if a series, the total amount authorized and the total amount outstanding;

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any limit on the amount that may be issued;

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whether or not we will issue the series of debt securities in global form, and if so, the terms and who the depository will be;

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the maturity date;

•

the principal amount due at maturity;

•

whether and under what circumstances, if any, we will pay additional amounts on any debt securities held by a person who is not a United States person for tax purposes, and whether we can redeem the debt securities if we have to pay such additional amounts;

•

the annual interest rate, which may be fixed or variable, or the method for determining the rate and the date interest will begin to accrue, the dates interest will be payable and the regular record dates for interest payment dates or the method for determining such dates;

•

whether or not the debt securities will be convertible into shares of our common stock or our preferred stock and, if so, the terms of such conversion;

•

whether or not the debt securities will be secured or unsecured by some or all of our assets, and the terms of any secured debt;

•

the terms of the subordination of any series of subordinated debt;

•

the place where payments will be payable;

•

restrictions on transfer, sale or other assignment, if any;

•

our right, if any, to defer payment or interest and the maximum length of any such deferral period;

•

the date, if any, after which and the conditions upon which, and the price at which, we may, at our option, redeem the series of debt securities pursuant to any optional or provisional redemption provisions and the terms of those redemptions provisions;

•

the date, if any, on which, and the price at which we are obligated, pursuant to any mandatory sinking fund or analogous fund provisions or otherwise, to redeem, or at the holder’s option to purchase, the series of debt securities and the currency or currency unit in which the debt securities are payable;

•

whether the indenture will restrict our ability to pay dividends, or will require us to maintain any asset ratios or reserves;

•

whether we will be restricted from incurring any additional indebtedness, issuing additional securities, or entering into a merger, consolidation or sale of our business;

•

a discussion of any material or special United States federal income tax considerations applicable to the debt securities;

•

information describing any book-entry features;

•

any provisions for payment of additional amounts for taxes;

•

whether the debt securities are to be offered at a price such that they will be deemed to be offered at an “original issue discount” as defined in paragraph (a) of Section 1273 of the Internal Revenue Code of 1986, as amended;

•

the denominations in which we will issue the series of debt securities, if other than denominations of $1,000 and any integral multiple thereof;

•

events of default;

•

whether we and/or the debenture trustee may change an indenture without the consent of any holders;

•

the form of debt security and how it may be exchanged and transferred;

•

description of the debenture trustee and paying agent, and the method of payments; and

•

any other specified terms, preferences, rights or limitations of, or restrictions on, the debt securities and any terms that may be required by us or advisable under applicable laws or regulations.

DESCRIPTION OF WARRANTS

The following description, together with the additional information we may include in any applicable prospectus supplements, summarizes the material terms and provisions of the warrants that we may offer under this prospectus and the related warrant agreements and warrant certificates. While the terms summarized below will apply generally to any warrants that we may offer, we will describe the particular terms of any series of warrants in more detail in the applicable prospectus supplement. If we indicate in the prospectus supplement, the terms of any warrants offered under that prospectus supplement may differ from the terms described below. If there are differences between that prospectus supplement and this prospectus, the prospectus supplement will control. Thus, the statements we make in this section may not apply to a particular series of warrants. Specific warrant agreements will contain additional important terms and provisions and will be incorporated by reference as an exhibit to the registration statement which includes this prospectus.

General

We may issue warrants for the purchase of common stock and/or preferred stock and/or debt securities in one or more series. We may issue warrants independently or together with common stock and/or preferred stock and/or debt securities, and the warrants may be attached to or separate from these securities.

We will evidence each series of warrants by warrant certificates that we may issue under a separate agreement. We may enter into the warrant agreement with a warrant agent. Each warrant agent may be a bank that we select which has its principal office in the United States and a combined capital and surplus of at least $50,000,000. We may also choose to act as out own warrant agent. We will indicate the name and address of any such warrant agent in the applicable prospectus supplement relating to a particular series of warrants.

We will describe in the applicable prospectus supplement the terms of the series of warrants, including:

•

the offering price and aggregate number of warrants offered;

•

the currency for which the warrants may be purchased;

•

in the case of warrants to purchase debt securities, the principal amount of debt securities purchasable upon exercise of one warrant and the price at, and currency in which, this principal amount of debt securities may be purchased upon such exercise;

•

if applicable, the designation and terms of the securities with which the warrants are issued and the number of warrants issued with each such security or each principal amount of such security;

•

if applicable, the date on and after which the warrants and the related securities will be separately transferable;

•

in the case of warrants to purchase common stock or preferred stock, the number of shares of common stock or preferred stock, as the case may be, purchasable upon the exercise of one warrant and the price at which these shares may be purchased upon such exercise;

•

the warrant agreement under which the warrants will be issued;

•

the effect of any merger, consolidation, sale or other disposition of our business on the warrant agreement and the warrants;

•

anti-dilution provisions of the warrants, if any;

•

the terms of any rights to redeem or call the warrants;

•

any provisions for changes to or adjustments in the exercise price or number of securities issuable upon exercise of the warrants;

•

the dates on which the right to exercise the warrants will commence and expire or, if the warrants are not continuously exercisable during that period, the specific date or dates on which the warrants will be exercisable;

•

the manner in which the warrant agreement and warrants may be modified;

•

the identities of the warrant agent and any calculation or other agent for the warrants;

•

federal income tax consequences of holding or exercising the warrants;

•

the terms of the securities issuable upon exercise of the warrants;

•

any securities exchange or quotation system on which the warrants or any securities deliverable upon exercise of the warrants may be listed; and

•

any other specific terms, preferences, rights or limitations of or restrictions on the warrants.

Before exercising their warrants, holders of warrants will not have any of the rights of holders of the securities purchasable upon such exercise, including:

•

in the case of warrants to purchase common stock or preferred stock, the right to receive dividends, if any, or, payments upon our liquidation, dissolution or winding up or to exercise voting rights, if any; or

•

in the case of warrants to purchase debt securities, the right to receive payments of principal of, or premium, if any, or interest on, the debt securities purchasable upon exercise or to enforce covenants in the applicable indenture.

Exercise of Warrants

Each warrant will entitle the holder to purchase the securities that we specify in the applicable prospectus supplement at the exercise price that we describe in the applicable prospectus supplement. Unless we otherwise specify in the applicable prospectus supplement, holders of the warrants may exercise the warrants at any time up to 5:00 p.m. Eastern Time on the expiration date that we set forth in the applicable prospectus supplement. After the close of business on the expiration date, unexercised warrants will become void.

Holders of the warrants may exercise the warrants by delivering the warrant certificate representing the warrants to be exercised together with specified information, and paying the required amount to the warrant agent in immediately available funds, as provided in the applicable prospectus supplement. We will set forth on the reverse side of the warrant certificate, and in the applicable prospectus supplement, the information that the holder of the warrant will be required to deliver to the warrant agent.

Until the warrant is properly exercised, no holder of any warrant will be entitled to any rights of a holder of the securities purchasable upon exercise of the warrant.

Upon receipt of the required payment and the warrant certificate properly completed and duly executed at the corporate trust office of the warrant agent or any other office indicated in the applicable prospectus supplement, we will issue and deliver the securities purchasable upon such exercise. If fewer than all of the warrants represented by the warrant certificate are exercised, then we will issue a new warrant certificate for the remaining amount of warrants. If we so indicate in the applicable prospectus supplement, holders of the warrants may surrender securities as all or part of the exercise price for warrants.

Enforceability of Rights By Holders of Warrants

Any warrant agent will act solely as our agent under the applicable warrant agreement and will not assume any obligation or relationship of agency or trust with any holder of any warrant. A single bank or trust company may act as warrant agent for more than one issue of warrants. A warrant agent will have no duty or responsibility in case of any default by us under the applicable warrant agreement or warrant, including any duty or responsibility to initiate any proceedings at law or otherwise, or to make any demand upon us. Any holder of a warrant may, without the consent of the related warrant agent or the holder of any other warrant, enforce by appropriate legal action its right to exercise, and receive the securities purchasable upon exercise of, its warrants in accordance with their terms.

Warrant Agreement Will Not Be Qualified Under Trust Indenture Act

No warrant agreement will be qualified as an indenture, and no warrant agent will be required to qualify as a trustee, under the Trust Indenture Act. Therefore, holders of warrants issued under a warrant agreement will not have the protection of the Trust Indenture Act with respect to their warrants.

Governing Law

Each warrant agreement and any warrants issued under the warrant agreements will be governed by New York law.

Calculation Agent

Calculations relating to warrants may be made by a calculation agent, an institution that we appoint as our agent for this purpose. The prospectus supplement for a particular warrant will name the institution that we have appointed to act as the calculation agent for that warrant as of the original issue date for that warrant. We may appoint a different institution to serve as calculation agent from time to time after the original issue date without the consent or notification of the holders.

The calculation agent’s determination of any amount of money payable or securities deliverable with respect to a warrant will be final and binding in the absence of manifest error.

DESCRIPTION OF UNITS

We may issue units comprised of one or more of the other securities described in this prospectus in any combination. Each unit will be issued so that the holder of the unit is also the holder of each security included in the unit. Thus, the holder of a unit will have the rights and obligations of a holder of each included security. The unit agreement under which a unit is issued may provide that the securities included in the unit may not be held or transferred separately, at any time or at any time before a specified date.

The applicable prospectus supplement will describe:

•

the designation and terms of the units and of the securities comprising the units, including whether and under what circumstances those securities may be held or transferred separately;

•

any unit agreement under which the units will be issued;

•

any provisions for the issuance, payment, settlement, transfer or exchange of the units or of the securities comprising the units; and

•

whether the units will be issued in fully registered or global form.

The applicable prospectus supplement will describe the terms of any units. The preceding description and any description of units in the applicable prospectus supplement does not purport to be complete and is subject to and is qualified in its entirety by reference to the unit agreement and, if applicable, collateral arrangements and depositary arrangements relating to such units.

PLAN OF DISTRIBUTION

We may sell the securities being offered pursuant to this prospectus through underwriters or dealers, through agents, or directly to one or more purchasers or through a combination of these methods. The applicable prospectus supplement will describe the terms of the offering of the securities, including:

•

the name or names of any underwriters, if any, and if required, any dealers or agents;

•

the purchase price of the securities and the proceeds we will receive from the sale;

•

any underwriting discounts and other items constituting underwriters’ compensation;

•

any discounts or concessions allowed or reallowed or paid to dealers; and

•

any securities exchange or market on which the securities may be listed.

We may distribute the securities from time to time in one or more transactions at:

•

a fixed price or prices, which may be changed;

•

market prices prevailing at the time of sale;

•

prices related to such prevailing market prices; or

•

negotiated prices.

Only underwriters named in the prospectus supplement are underwriters of the securities offered by the prospectus supplement.

If underwriters are used in an offering, we will execute an underwriting agreement with such underwriters and will specify the name of each underwriter and the terms of the transaction (including any underwriting discounts and other terms constituting compensation of the underwriters and any dealers) in a prospectus supplement. The securities may be offered to the public either through underwriting syndicates represented by managing underwriters or directly by one or more investment banking firms or others, as designated. If an underwriting syndicate is used, the managing underwriter(s) will be specified on the cover of the prospectus supplement. If underwriters are used in the sale, the offered securities will be acquired by the underwriters for their own accounts and may be resold from time to time in one or more transactions, including negotiated transactions, at a fixed public offering price or at varying prices determined at the time of sale. Any public offering price and any discounts or concessions allowed or re-allowed or paid to dealers may be changed from time to time. Unless otherwise set forth in the prospectus supplement, the obligations of the underwriters to purchase the offered securities will be subject to conditions precedent and the underwriters will be obligated to purchase all of the offered securities if any are purchased.

We may grant to the underwriters options to purchase additional securities to cover over-allotments, if any, at the public offering price, with additional underwriting commissions or discounts, as may be set forth in a related prospectus supplement. The terms of any over-allotment option will be set forth in the prospectus supplement for those securities.

If we use a dealer in the sale of the securities being offered pursuant to this prospectus or any prospectus supplement, we will sell the securities to the dealer, as principal. The dealer may then resell the securities to the public at varying prices to be determined by the dealer at the time of resale. The names of the dealers and the terms of the transaction will be specified in a prospectus supplement.

We may sell the securities directly or through agents we designate from time to time. We will name any agent involved in the offering and sale of securities and we will describe any commissions we will pay the agent in the prospectus supplement. Unless the prospectus supplement states otherwise, any agent will act on a best-efforts basis for the period of its appointment.

We may authorize agents or underwriters to solicit offers by institutional investors to purchase securities from us at the public offering price set forth in the prospectus supplement pursuant to delayed delivery contracts providing for payment and delivery on a specified date in the future. We will describe the conditions to these contracts and the commissions we must pay for solicitation of these contracts in the prospectus supplement.

In connection with the sale of the securities, underwriters, dealers or agents may receive compensation from us or from purchasers of the common stock for whom they act as agents in the form of discounts, concessions or commissions. Underwriters may sell the securities to or through dealers, and those dealers may receive compensation in the form of discounts, concessions or commissions from the underwriters or commissions from the purchasers for whom they may act as agents. Underwriters, dealers and agents that participate in the distribution of the securities, and any institutional investors or others that purchase common stock directly and then resell the securities, may be deemed to be underwriters, and any discounts or commissions received by them from us and any profit on the resale of the common stock by them may be deemed to be underwriting discounts and commissions under the Securities Act.

We may provide agents and underwriters with indemnification against particular civil liabilities, including liabilities under the Securities Act, or contribution with respect to payments that the agents or underwriters may make with respect to such liabilities. Agents and underwriters may engage in transactions with, or perform services for, us in the ordinary course of business.

In addition, we may enter into derivative transactions with third parties (including the writing of options), or sell securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement indicates, in connection with such a transaction, the third parties may, pursuant to this prospectus and the applicable prospectus supplement, sell securities covered by this prospectus and the applicable prospectus supplement. If so, the third party may use securities borrowed from us or others to settle such sales and may use securities received from us to close out any related short positions. We may also loan or pledge securities covered by this prospectus and the applicable prospectus supplement to third parties, who may sell the loaned securities or, in an event of default in the case of a pledge, sell the pledged securities pursuant to this prospectus and the applicable prospectus supplement. The third party in such sale transactions will be an underwriter and will be identified in the applicable prospectus supplement or in a post-effective amendment.

To facilitate an offering of a series of securities, persons participating in the offering may engage in transactions that stabilize, maintain, or otherwise affect the market price of the securities. This may include over-allotments or short sales of the securities, which involves the sale by persons participating in the offering of more securities than have been sold to them by us. In those circumstances, such persons would cover such over-allotments or short positions by purchasing in the open market or by exercising the over-allotment option granted to those persons. In addition, those persons may stabilize or maintain the price of the securities by bidding for or purchasing securities in the open market or by imposing penalty bids, whereby selling concessions allowed to underwriters or dealers participating in any such offering may be reclaimed if securities sold by them are repurchased in connection with stabilization transactions. The effect of these transactions may be to stabilize or maintain the market price of the securities at a level above that which might otherwise prevail in the open market. Such transactions, if commenced, may be discontinued at any time. We make no representation or prediction as to the direction or magnitude of any effect that the transactions described above, if implemented, may have on the price of our securities.

Any common stock sold pursuant to a prospectus supplement will be eligible for quotation and trading on The NASDAQ Capital Market. Any underwriters to whom securities are sold by us for public offering and sale may make a market in the securities, but such underwriters will not be obligated to do so and may discontinue any market making at any time without notice.

In order to comply with the securities laws of some states, if applicable, the securities offered pursuant to this prospectus will be sold in those states only through registered or licensed brokers or dealers. In addition, in some states securities may not be sold unless they have been registered or qualified for sale in the applicable state or an exemption from the registration or qualification requirement is available and complied with.

In compliance with guidelines of the Financial Industry Regulatory Authority, or FINRA, the maximum consideration or discount to be received by any FINRA member or independent broker dealer may not exceed 8% of the aggregate amount of the securities offered pursuant to this prospectus and any applicable prospectus supplement.

LEGAL MATTERS

The validity of the securities being offered hereby will be passed upon by Sichenzia Ross Friedman Ference LLP, New York, New York.

EXPERTS

Our financial statements incorporated by reference into this prospectus as of and for the fiscal years ended December 31, 2011 and 2010 (as indicated in their reports) have been audited by Peterson Sullivan LLP, Seattle, Washington, an independent registered public accounting firm and are included herein in reliance upon the authority as experts in giving said reports.

WHERE YOU CAN FIND MORE INFORMATION

This prospectus constitutes a part of a registration statement on Form S-3 filed under the Securities Act. As permitted by the SEC’s rules, this prospectus and any prospectus supplement, which form a part of the registration statement, do not contain all the information that is included in the registration statement. You will find additional information about us in the registration statement. Any statements made in this prospectus or any prospectus supplement concerning legal documents are not necessarily complete and you should read the documents that are filed as exhibits to the registration statement or otherwise filed with the SEC for a more complete understanding of the document or matter.

We file annual, quarterly and current reports, proxy statements and other information with the SEC. You may read, without charge, and copy the documents we file at the SEC’s public reference rooms in Washington, D.C. at 100 F Street, NE, Room 1580, Washington, DC 20549, or in New York, New York and Chicago, Illinois. You can request copies of these documents by writing to the SEC and paying a fee for the copying cost. Please call the SEC at 1-800-SEC-0330 for further information on the public reference rooms. Our SEC filings are also available to the public at no cost from the SEC’s website at http://www.sec.gov.

INCORPORATION OF DOCUMENTS BY REFERENCE

We have filed a registration statement on Form S-3 with the Securities and Exchange Commission under the Securities Act. This prospectus is part of the registration statement but the registration statement includes and incorporates by reference additional information and exhibits. The Securities and Exchange Commission permits us to “incorporate by reference” the information contained in documents we file with the Securities and Exchange Commission, which means that we can disclose important information to you by referring you to those documents rather than by including them in this prospectus. Information that is incorporated by reference is considered to be part of this prospectus and you should read it with the same care that you read this prospectus. Information that we file later with the Securities and Exchange Commission will automatically update and supersede the information that is either contained, or incorporated by reference, in this prospectus, and will be considered to be a part of this prospectus from the date those documents are filed. We have filed with the Securities and Exchange Commission, and incorporate by reference in this prospectus:

•

our Annual Report on Form 10-K for the fiscal year ended December 31, 2011, filed with the SEC pursuant to Section 13 of the Exchange Act on April 13, 2012, respectively;

•

our Quarterly Report on Form 10-Q for the three-month period ended March 31, 2012, filed with the SEC pursuant to Section 13 of the Exchange Act on May 21, 2012;

•

our Quarterly Report on Form 10-Q and Form 10-Q/A for the six-month period ended June 30, 2012, filed with the SEC pursuant to Section 13 of the Exchange Act on August 14 and September 12, 2012, respectively;

•

our Quarterly Report on Form 10-Q for the nine-month period ended September 30, 2012, filed with the SEC pursuant to Section 13 of the Exchange Act on November 14, 2012;

•

our Current Reports on Form 8-K, filed with the SEC pursuant to Section 13 of the Exchange Act on February 6, 2012, February 15, 2012, April 6, 2012, April 17, 2012, May 23, 2012, July 20, 2012, August 23, 2012, August 31, 2012, September 17, 2012, September 26, 2012, October 3, 2012, December 7, 2012 and December 11, 2012;

•

the description of our common stock contained in our registration statement on Form 8-A (File No. 001-35737) filed with the SEC on November 14, 2012, including any amendment or report filed for the purpose of updating such description; and

We also incorporate by reference all additional documents that we file with the Securities and Exchange Commission under the terms of Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act that are made after the initial filing date of the registration statement of which this prospectus is a part until the offering of the particular securities covered by a prospectus supplement or term sheet has been completed. We are not, however, incorporating, in each case, any documents or information that we are deemed to furnish and not file in accordance with Securities and Exchange Commission rules.

You may request, and we will provide you with, a copy of these filings, at no cost, by calling us at (240) 497-9024 or by writing to us at the following address:

Northwest Biotherapeutics, Inc.
4800 Montgomery Lane, Suite 800
Bethesda, MD 20814
Attention: Secretary

One Long-Term Warrant to Purchase 0.25 Shares of Common Stock and
One Over-Allotment Warrant to Purchase 0.25 Shares of Common Stock

	Per Unit		Total
Offering Price	$	3.35	$	15,000,000
Placement agent’s fees⁽¹⁾	$	0.21775	$	975,000
Proceeds, before expenses, to us	$	3.13225	$	14,025,000

Oppenheimer & Co.			Summer Street Research Partners
Lead Placement Agent			Co-Placement Agent

The date of this prospectus supplement is August 8, 2013.

	Page
About this Prospectus Supplement	ii
Cautionary Statement Regarding Forward-Looking Statements	iii
Prospectus Supplement Summary	S-1
Risk Factors	S-5
Use of Proceeds	S-18
Dividend Policy	S-18
Dilution	S-19
Capitalization	S-20
Description of Securities	S-21
Plan of Distribution	S-23
Legal Matters	S-25
Experts	S-25
Where You Can Find More Information	S-25
Incorporation of Certain Information By Reference	S-26


The Offering

*Securities offered by us*	4,477,612 units, each unit consisting of one share of common stock, one long-term warrant to purchase 0.25 shares of common stock, and one over-allotment warrant to purchase 0.25 shares of common stock.

*Unit price*	$3.35 per unit

*Warrants*	The exercise price of the long-term warrants is $4.00 per share. The exercise price of the over-allotment warrants is $3.35 per share. The long-term warrants are exercisable beginning six months after the date of issuance, and will expire five years after they become exercisable. The over-allotment warrants are exercisable immediately, and expire one year after the date of issuance. Please refer to the “Description of Warrants” as set forth under “Description of Securities.”

*Common stock to be outstanding after this offering*	31,618,029 shares or 33,856,835 shares if the warrants sold in this offering are exercised in full.

*Use of proceeds*	We intend to use the net proceeds from this offering to fund our research and development activities and for working capital and other general corporate purposes. See “Use of Proceeds” on page S-18.

*Risk factors*	See “Risk Factors” beginning on page S-5 of this prospectus supplement and other information included or incorporated by reference into this prospectus supplement and the accompanying prospectus for a discussion of factors you should carefully consider before investing in our securities.

*NASDAQ Capital Market Trading symbol*	“NWBO”

The number of shares of our common stock to be outstanding immediately after this offering is based on 27,140,417 shares outstanding as of March 31, 2013, and does not include, as of that date:

• 1,551,000 shares of our common stock subject to outstanding options having a weighted average exercise price of $10.56 per share;

• 12,177,411 shares of our common stock that have been reserved for issuance upon exercise of outstanding warrants at a weighted average exercise price of $6.82 per share;

• 2,564,108 shares of common stock and warrants to purchase 1,025,641 shares of common stock (with an exercise price of $4.29 per share) issued on April 19, 2013; and

• 2,902,072 shares of common stock issued in August 2013 to Cognate BioServices, Inc. upon conversion of notes payable to Cognate BioServices in the aggregate amount of $11.6 million.

	As of March 31, 2013 (in thousands, except share data)
	Actual			Pro forma			Pro forma, as adjusted
Stockholders’ equity (deficiency):

Preferred stock, $0.001 par value, 20,000,000 shares authorized, actual and 40,000,000 shares authorized, pro forma and pro forma, as adjusted; 0 shares issued and outstanding, actual, pro forma and pro forma, as adjusted	$	—		$	—		$	—

Common stock, $0.001 par value, 450,000,000 shares authorized, 27,140,417 shares issued and outstanding, actual; 33,861,841 and 38,339,453 shares issued and outstanding, pro forma and pro forma, as adjusted, respectively.		27			30			34

Additional paid-in capital		305,604			318,117			331,840

Deficit accumulated during the development stage		(333,492	)		(333,492	)		(333,492	)

Cumulative translation adjustment		(190	)		(190	)		(190	)

Total stockholders’ equity(deficiency)		(28,051	)		(15,535	)		(1,808	)

Offering price per unit				$	3.35
Net tangible book value per share as of March 31, 2013	$	(1.03	)
Increase in net tangible book value per share after this offering	$	0.58
Pro forma net tangible book value per share after this offering				$	(0.45	)

Dilution per share to new investors in this offering				$	3.80

Prospectus

$100,000,000 of Common Stock, Preferred Stock, Warrants Debt Securities, and/or Units

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS

PROSPECTUS SUMMARY

Business Overview

Recent Developments

Corporate Information

RISK FACTORS

Risks Related to our Business

We will need to raise substantial funds, on an ongoing basis, for general corporate purposes and operations, including our clinical trials. Such funding may not be available or may not be available on attractive terms.

We are likely to continue to incur substantial losses, and may never achieve profitability.

Our auditors have issued a “going concern” audit opinion.

As a development stage company with a novel technology and unproven business strategy, our limited history of operations makes an evaluation of our business and prospects difficult.

We will need to expand our management and technical personnel as our operations progress, and we may not be able to recruit such additional personnel and/or retain existing personnel.

We rely at present on third-party contract manufacturers. As a result, we may be at risk for capacity limitations and/or supply disruptions.

The manufacturing of our product candidates will have to be greatly scaled up for commercialization, and neither we nor other parties in the industry have experience with such scale-up.

The necessary specialized facilities, equipment and personnel may not be available or obtainable for the scale-up of manufacturing of our product candidates.

Our technology is novel, involves complex immune system elements, and may not prove to be effective.

Clinical trials for our product candidates are expensive and time consuming, and their outcome is uncertain.

We may be required to suspend or discontinue clinical trials due to unexpected side effects or other safety risks that could preclude approval of our product candidates.

We have limited experience in conducting and managing clinical trials.

Multiple late stage clinical trials of DCVax-L for GBM, our lead product, may be required before we can obtain regulatory approval.

Changes in manufacturing methods for DCVax-L could require us to conduct equivalency studies and/or additional clinical trials.

We may not receive regulatory approvals for our product candidates or there may be a delay in obtaining such approvals.

We may fail to comply with regulatory requirements.

Regulatory approval of our product candidates may be withdrawn at any time.

Our product candidates will require a different distribution model than conventional therapeutic products, and this may impede commercialization of our product candidates.

Our product candidates will require different marketing and sales methods and personnel than conventional therapeutic products. Also, we lack sales and marketing experience. These factors may result in significant difficulties in commercializing our product candidates.

We may not obtain or maintain the benefits associated with orphan drug status, including market exclusivity.

The availability and amount of potential reimbursement for our product candidates by government and private payers is uncertain and may be delayed and/or inadequate.

Competition in the biotechnology and biopharmaceutical industry is intense and most of our competitors have substantially greater resources than we do.

Competing generic medicinal products may be approved.

We may be exposed to potential product liability claims, and our existing insurance may not cover these claims in whole or in part. In addition, insurance against such claims may not be available to us on reasonable terms in the future, if at all.

Our intellectual property rights may be overturned, narrowed or blocked, and may not provide sufficient commercial protection for our product candidates, or third parties may infringe upon our intellectual property.

We may be exposed to claims or lawsuits — with or without merit — on various subjects, including that our products infringe patents or other proprietary rights of other parties.

DCVax is our only technology in clinical development.

Collaborations play an important role in our business, and could be vulnerable to competition or termination.

Our business could be adversely affected by new legislation and/or product related issues.

Our business could be adversely affected by animal rights activists.

Risks Related to our Common Stock

The market price of our common stock may be volatile and adversely affected by several factors.

Toucan Capital and its affiliates are the principal holders of our shares of common stock, and this concentration of ownership may have a negative effect on the market price of our common stock.

The requirements of the Sarbanes-Oxley Act of 2002 and other U.S. securities laws impose substantial costs, and may drain our resources and distract our management.

Our management and our independent auditor have identified internal control deficiencies, which our management and our independent auditor believe constitute material weaknesses.

We do not intend to pay any cash dividends in the foreseeable future and, therefore, any return on your investment in our common stock must come from increases in the market price of our common stock.

Our certificate of incorporation and bylaws, our shareholder rights plan and Delaware law have anti-takeover provisions that could discourage, delay or prevent a change in control, which may cause our stock price to decline.

SPECIAL NOTE REGARDING FORWARD-LOOKING STATEMENTS

USE OF PROCEEDS

RATIO OF EARNINGS TO FIXED CHARGES

THE SECURITIES WE MAY OFFER

DESCRIPTION OF CAPITAL STOCK

General

Common Stock

Preferred Stock

Transfer Agent and Registrar

Anti-Takeover Effects of Certain Provisions of our Certificate of Incorporation, Bylaws and the DGCL

Delaware Anti-takeover Law

Rights Plan

Amended and Restated Certificate of Incorporation and Bylaw Provisions

DESCRIPTION OF DEBT SECURITIES

DESCRIPTION OF WARRANTS

General

Exercise of Warrants

Enforceability of Rights By Holders of Warrants

Warrant Agreement Will Not Be Qualified Under Trust Indenture Act

Governing Law

Calculation Agent

DESCRIPTION OF UNITS

PLAN OF DISTRIBUTION

LEGAL MATTERS

EXPERTS

WHERE YOU CAN FIND MORE INFORMATION

INCORPORATION OF DOCUMENTS BY REFERENCE

$100,000,000 of
Common Stock,
Preferred Stock,
Warrants
Debt Securities, and/or
Units