8-K

UNITED STATES
SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 8-K

CURRENT REPORT
Pursuant to Section 13 or 15(d) of the
Securities Exchange Act of 1934

Date of Report (Date of earliest event reported):   January 25, 2008

Penwest Pharmaceuticals Co.

(Exact Name of Registrant as Specified in Charter)

Washington
(State or Other Juris-
diction of Incorporation) 000-23467
(Commission
File Number) 91-1513032
(IRS Employer
Identification No.)

39 Old Ridgebury Road, Suite 11
Danbury, Connecticut
(Address of Principal Executive Offices)
06810-5120
(Zip Code)

Registrant’s telephone number, including area code:   (877) 736-9378

Not Applicable
(Former Name or Former Address, if Changed Since Last Report)

Check the appropriate box below if the Form 8-K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions (see General Instruction A.2. below):

¨ Written communications pursuant to Rule 425 under the Securities Act (17 CFR 230.425)

¨ Soliciting material pursuant to Rule 14a-12 under the Exchange Act (17 CFR 240.14a-12)

¨ Pre-commencement communications pursuant to Rule 14d-2(b) under the Exchange Act (17 CFR 240.14d-2(b))

¨ Pre-commencement communications pursuant to Rule 13e-4(c) under the Exchange Act (17 CFR 240.13e-4(c))

TABLE OF CONTENTS

	Item 8.01.    Other Events.
	Item 9.01.    Financial Statements and Exhibits.
SIGNATURE
EXHIBIT INDEX
EX-99.1 Press Release, dated February 4, 2008
EX-99.1 Press Release, dated January 25, 2008

Item 8.01.    Other Events.

     Phase IIa Clinical Trial Results

     On February 4, 2008, Penwest Pharmaceuticals Co. announced in a press release the results from its Phase IIa clinical trial evaluating nalbuphine hydrochloride extended-release tablets. The press release issued by Penwest is filed as Exhibit 99.1 to this Current Report on Form 8-K and is incorporated herein by reference.

     Impax Litigation

     On January 25, 2008, Penwest announced that it and Endo Pharmaceuticals, Inc. had filed a second lawsuit against Impax Laboratories Inc. in the United States District Court for the District of Delaware in connection with Impax’s Abbreviated New Drug Application, or ANDA, for Opana ER (oxymorphone HCI) extended-release tables. Penwest and Endo originally filed a lawsuit against Impax in the United States District Court for the District of Delaware on November 15, 2007 alleging infringement of two of Penwest’s patents listed in the FDA’s Orange Book and also seeking a declaratory judgment that, among other things, Impax had no basis to trigger the Hatch-Waxman ANDA patent litigation process by delivering to Endo and Penwest a series of Paragraph IV Patent Certification notices in October and November 2007 with respect to Penwest’s patents listed in the Orange Book because the FDA, according to Impax, had rescinded its acceptance of Impax’s ANDA prior to such date. In addition, Penwest and Endo asked the court to declare the Paragraph IV Patent Certification notices that Impax had served on Endo and Penwest to be null, void and of no legal effect.

     On December 6, 2007, Impax announced that it had submitted additional information to the FDA in connection with its ANDA and, on December 17, 2007, announced that the FDA had accepted the ANDA for review as of November 23, 2007. At the FDA’s instruction, on December 13, 2007 Impax sent Penwest a new Paragraph IV Patent Certification notice with respect to the same Orange Book-listed patents covered in Impax’s prior Paragraph IV Patent Certification notices. In this notice, Impax stated that it would not withdraw its prior Paragraph IV Patent Certification notices because it believed they were properly provided and because Impax was reserving its right to challenge the FDA’s rescission of its initial acceptance of Impax’s ANDA. As a result of the FDA’s determination of the ANDA filing date and the receipt of the new Paragraph IV Certification notice, on December 20, 2007, Penwest and Endo filed a notice of dismissal of the portion of its November 15, 2007 complaint seeking declaratory judgment that, among other things, Impax had no basis to trigger the Hatch-Waxman ANDA patent litigation process and that any Paragraph IV Patent Certification notices served prior to November 23, 2007 were null, void and of no legal effect. Penwest and Endo did not dismiss the patent infringement claims because Impax refused to withdraw its prior Paragraph IV Patent Certification notices.

     The January lawsuit alleges infringement of the same patents Penwest and Endo alleged infringement of in the November litigation. The press release announcing the new litigation is filed as Exhibit 99.2 to this Current Report on Form 8-K and is incorporated herein by reference.

Item 9.01.    Financial Statements and Exhibits.

(d)	Exhibits
	99.1      Press Release, dated February 4, 2008
	99.2      Press Release, dated January 25, 2008.

SIGNATURE

     Pursuant to the requirements of the Securities Exchange Act of 1934, the Registrant has duly caused this report to be signed on its behalf by the undersigned hereunto duly authorized.

	PENWEST PHARMACEUTICALS CO.
Date:  February 11, 2008	By:	/s/ Benjamin L. Palleiko
		Benjamin L. Palleiko
		Senior Vice President, Corporate Development and Chief Financial Officer

EXHIBIT INDEX

Exhibit No.	Description
99.1	Press Release, dated February 4, 2008
99.2	Press Release, dated January 25, 2008

EX-99.1

EXHIBIT 99.1

Penwest Announces Results of Phase IIa Clinical Study of Nalbuphine ER

Company Intends to Advance Nalbuphine ER Into Phase IIb

DANBURY, Conn., Feb. 4, 2008 (PRIME NEWSWIRE) — Penwest Pharmaceuticals Co. (Nasdaq:PPCO) today reported results from the Company’s Phase IIa clinical trial evaluating nalbuphine hydrochloride extended release tablets (nalbuphine ER), a product Penwest is developing for the treatment of moderate chronic pain. The Company has concluded that the results of this study showed efficacy sufficient to support its continued development of the drug, and it plans to conduct a Phase IIb trial commencing in the second half of this year.

This was Penwest’s first clinical trial of nalbuphine ER in a chronic pain population. The Company designed the trial with multiple endpoints related to clinical pain relief in an effort to understand the activity of the drug and provide the basis for designing the Phase IIb study. The primary endpoint of the study was the Sum of Pain Intensity Differences between baseline and day 21. Nalbuphine ER did not meet this endpoint, which the Company believes was primarily due to patient dropouts in the first week of dosing. The drug did, however, achieve a number of the secondary endpoints in the trial leading the Company to conclude that proof of concept had been established for the drug. For instance, nalbuphine ER demonstrated statistical significance in the intent-to-treat population when compared to placebo, as measured by the Global Assessment of Pain Control (p=0.006) and by the Integrated Assessment of Pain Intensity and Rescue Medication Use (p=0.009).

No drug related serious adverse events were reported during the trial. Twenty four percent of the nalbuphine ER patients reported no side effects, 66% reported side effects that were characterized as mild or moderate in severity, and 10% reported severe side effects.

Jennifer L. Good, Penwest’s President and CEO, said, “Nalbuphine ER is our lead product candidate, and in establishing the proof of concept in chronic pain, we have reached an important milestone for this program. Our development team will continue to evaluate the data generated from this trial and use it in designing our planned Phase IIb study. We are also initiating partnering discussions for nalbuphine ER in Europe, and at this point in time plan to retain the U.S. rights for Penwest.”

The goal of the Phase IIb trial will be to demonstrate statistically significant analgesic efficacy of the drug versus placebo using an accepted clinical endpoint, characterize a clinically meaningful titration regimen, and demonstrate that the analgesic efficacy is sustained over the twelve hour dosing interval. The Company believes this trial will take approximately one year to complete.

The Phase IIa trial was a randomized, double-blind, placebo controlled design, with a forced weekly dose escalation. The main objective of this trial was to evaluate the analgesic efficacy of nalbuphine ER in a patient population experiencing chronic pain. There were 138 patients with chronic pain secondary to osteoarthritis of the knee or hip in the intent-to-treat population of this trial. Patients enrolled in the trial were given the lowest dose of the drug for week one, increased to a mid-dose level for week two, and increased to the highest dose studied for week three. The study group included a 2-to-1 randomization of patients on drug versus placebo.

Nalbuphine ER, designed to be taken as a twice-daily tablet, is formulated using Penwest’s TIMERx(r) drug delivery technology. Penwest previously conducted multiple Phase I studies on nalbuphine ER to establish the pharmacokinetic profile and generate safety data. The Company has also conducted a Phase IIa study of nalbuphine ER for an acute pain model in which a single dose of nalbuphine ER reduced mean pain intensity in a dose-dependent manner over a 12-hour study period when compared to placebo. Nalbuphine is currently available only as an injection medication.

Ms. Good, Dr. Thomas Sciascia, Penwest’s Chief Medical Officer, and Paul Hayes, the Company’s Vice President of Strategic Marketing, will conduct a conference call at 11:00 a.m. EST today to discuss the results of the nalbuphine ER Phase IIa study and the market opportunity. The dial-in numbers for the call are:

Domestic Telephone Number:	877-852-5337
International Telephone Number:	706-679-2324
The Conference ID is “Penwest.”	33877837

The conference call will be accessible live and as a replay on the Investor Relations section of the Penwest website at http://www.penwest.com.

About Penwest Pharmaceuticals

Penwest is a drug development company dedicated to bringing to the marketplace innovative products that help improve the lives of patients. The Company’s goal is to identify, develop and commercialize prescription products that address unmet medical needs, primarily for diseases of the nervous system. Penwest is currently applying its drug delivery and drug development expertise to a pipeline of potential products that are in various stages of development and that it intends to commercialize independently or through third party alliances.

Penwest Forward-Looking Statement

The matters discussed herein contain forward-looking statements that involve risks and uncertainties, which may cause Penwest’s actual results in future periods to be materially different from any future performance suggested herein. For this purpose, any statements contained herein that are not statements of historical fact may be deemed to be forward-looking statements. Without limiting the foregoing, the words “believes,” “anticipates,” “plans,” “expects,” “intends,” “potential” and similar expressions are intended to identify forward-looking statements. Important factors that could cause results to differ materially include: risks relating to the commercial success of Opana ER and our reliance on Endo for the commercial success of Opana ER, regulatory risks relating to drugs in development, including the timing and outcome of regulatory submissions and regulatory actions; uncertainty of success of collaborations; the timing of clinical trials, such as the planned Phase IIb trial of nalbuphine ER referred to above; whether the results of clinical trials such as the results of the trial referred to above will warrant further clinical trials, warrant submission of an application for regulatory approval of, or warrant the regulatory approval of, the product that is the subject of the trial; whether the patents and patent applications owned by Penwest will protect the Company’s products and technology and prevent others from infringing it; actual and potential competition; the need for capital; and other risks as set forth under the caption Risk Factors in Penwest’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 8, 2007, which risk factors are incorporated herein by reference.

The forward-looking statements contained in this press release speak only as of the date of the statement made. Penwest disclaims any intention or obligation to update any forward-looking statements. TIMERx is a registered trademark of Penwest. All other trademarks referenced herein are the property of their respective owners.

CONTACT:	Penwest
	Investors:
	Ben Palleiko/Diane D’Alessandro
	(203) 796-3700
	(877) 736-9378
	Kekst and Company
	Media:
	Caroline Gentile
	(212) 521-4800

EX-99.2

EXHIBIT 99.2

Endo and Penwest File Lawsuit Against Impax Laboratories Relating to OPANA(R) ER

CHADDS FORD, PA and DANBURY, CT, Jan 25, 2008 (MARKET WIRE via COMTEX News Network) — Endo Pharmaceuticals Inc., a subsidiary of Endo Pharmaceuticals Holdings Inc. (NASDAQ: ENDP), and Penwest Pharmaceuticals Co. (NASDAQ: PPCO) announced today that they have filed a lawsuit against IMPAX Laboratories, Inc. in the United States District Court for the District of Delaware in connection with IMPAX’s Abbreviated New Drug Application (ANDA) for OPANA(R) ER (oxymorphone HCl) extended-release tablets CII.

The lawsuit is in response to IMPAX’s notice to Endo and Penwest, announced on December 17, 2007, advising of the FDA’s acceptance for substantive review, as of November 23, 2007, of IMPAX’s ANDA containing a Paragraph IV certification under 21 U.S.C. Section 355(j) for oxymorphone hydrochloride extended-release tablets CII. IMPAX stated in its Paragraph IV certification notice letter that the FDA requested IMPAX to provide notification to Endo and Penwest of this certification. IMPAX’s Paragraph IV certification notice refers to certain Penwest patents listed in the FDA’s Orange Book relating to the formulation of OPANA ER. The complaint filed today alleges infringement of certain of these Orange Book-listed patents.

As previously disclosed, Endo and Penwest filed a lawsuit against IMPAX on November 15, 2007 in the United States District Court for the District of Delaware in response to a series of Paragraph IV certification notices that Endo and Penwest assert were wrongfully served on them by IMPAX. These prior Paragraph IV Certification Notices related to the same Orange Book-listed patents for OPANA ER and were served on Endo and Penwest after the acceptance of IMPAX’s ANDA was rescinded by the FDA. Endo and Penwest continue to believe that these prior Paragraph IV Certification Notices are null, void and of no legal effect.

OPANA ER has been granted new dosage form regulatory exclusivity that prevents the FDA from approving any ANDA for a generic version of OPANA ER for launch prior to June 22, 2009, the date such regulatory exclusivity expires.

About Endo

Endo Pharmaceuticals Holdings Inc. is a fully integrated specialty pharmaceutical company with market leadership in pain management products. Through its Endo Pharmaceuticals Inc. subsidiary, the company researches, develops, produces and markets a broad product offering of both branded and generic pharmaceuticals, meeting the needs of healthcare professionals and consumers alike. More information, including this and past press releases of Endo Pharmaceuticals Holdings Inc., is available online at www.endo.com.

About Penwest Pharmaceuticals

Penwest is a drug development pharmaceutical company dedicated to bringing to the marketplace innovative products that help improve the lives of patients. The Company’s goal is to identify, develop and commercialize prescription products that address unmet medical needs, primarily for diseases of the nervous system. Penwest is currently applying its drug delivery and drug development expertise to a pipeline of potential products that are in various stages of development and that it intends to commercialize independently or through third party alliances.

Endo Forward-Looking Statement

This press release contains forward-looking statements, within the meaning of Section 27A of the Securities Act of 1933 and Section 21E of the Securities Exchange Act of 1934, as amended, that are based on management’s beliefs and assumptions, current expectations, estimates and projections. Statements that are not historical facts, including statements which are preceded by, followed by, or that include, the words “believes,” “anticipates,” “plans,” “expects” or similar expressions and statements are forward-looking statements. Endo’s estimated or anticipated future results, product performance or other non-historical facts are forward-looking and reflect Endo’s current perspective on existing trends and information. Many of the factors that will determine the Company’s future results are beyond the ability of the Company to control or predict. These statements are subject to risks and uncertainties and, therefore, actual results may differ materially from those expressed or implied by these forward-looking statements. The reader should not rely on any forward-looking statement. The Company undertakes no obligation to update any forward-looking statements whether as a result of new information, future events or otherwise. Several important factors, in addition to the specific factors discussed in connection with these forward-looking statements individually, could affect the future results of Endo and could cause those results to differ materially from those expressed in the forward-

looking statements contained in this press release. Important factors that may affect future results include, but are not limited to: market acceptance of the Company’s products and the impact of competitive products and pricing; dependence on sole source suppliers; the success of the Company’s product development activities and the timeliness with which regulatory authorizations and product launches may be achieved; successful compliance with extensive, costly, complex and evolving governmental regulations and restrictions; the availability on commercially reasonable terms of raw materials and other third party manufactured products; exposure to product liability and other lawsuits and contingencies; dependence on third party suppliers, distributors and collaboration partners; the ability to timely and cost effectively integrate acquisitions; uncertainty associated with pre-clinical studies and clinical trials and regulatory approval; uncertainty of market acceptance of new products; the difficulty of predicting FDA approvals; risks with respect to technology and product development; the effect of competing products and prices; uncertainties regarding intellectual property protection; uncertainties as to the outcome of litigation; a determination by a regulatory agency that we are engaging in inappropriate sales or marketing activities, including promoting the “off-label” use of our products; changes in operating results; impact of competitive products and pricing; product development; changes in laws and regulations; customer demand; possible future litigation; availability of future financing and reimbursement policies of government and private health insurers and others; and other risks and uncertainties detailed in Endo’s filings with the Securities and Exchange Commission, including its Annual Report on Form 10-K filed with the SEC on March 1, 2007. Readers should evaluate any statement in light of these important factors.

Penwest Forward-Looking Statement

The matters discussed herein contain forward-looking statements that involve risks and uncertainties, which may cause Penwest’s actual results in future periods to be materially different from any future performance suggested herein. For this purpose, any statements contained herein that are not statements of historical fact may be deemed to be forward-looking statements. Without limiting the foregoing, the words “believes,” “anticipates,” “plans,” “expects,” “intends,” “potential” and similar expressions are intended to identify forward-looking statements. Important factors that could cause results to differ materially include: risks relating to the commercial success of Opana ER and our reliance on Endo for the commercial success of Opana ER, regulatory risks relating to drugs in development, including the timing and outcome of regulatory submissions and regulatory actions; uncertainty of success of collaborations; the timing of clinical trials, including the impact of enrollment rates; whether the results of clinical trials will warrant further clinical trials, warrant submission of an application for regulatory approval of, or warrant the regulatory approval of, the product that is the subject of the trial; whether the patents and patent applications owned by Penwest will protect Penwest’s products and technology and prevent others from infringing it; actual and potential competition; the need for capital; and other risks as set forth under the caption Risk Factors in Penwest’s Quarterly Report on Form 10-Q filed with the Securities and Exchange Commission on November 8, 2007, which risk factors are incorporated herein by reference.

The forward-looking statements contained in this press release speak only as of the date of the statement made. Penwest disclaims any intention or obligation to update any forward-looking statements.

All trademarks referenced herein are the property of their respective owners.