Filed Pursuant to Rule 424(b)(5)
Registration No. 333-253485

Prospectus Supplement

(To Prospectus dated May 7, 2021)

Up to $125,000,000

COMMON STOCK

We have entered into a distribution agreement with J.P. Morgan Securities LLC and BofA Securities, Inc., or the Agents, relating to shares of our common stock offered by this prospectus supplement and the accompanying prospectus. In accordance with the terms of the distribution agreement, we may offer and sell from time to time shares of our common stock having an aggregate gross offering price of up to $125,000,000 through the Agents, acting as our agents or principals.

Our common stock is listed on the Nasdaq Global Select Market under the symbol “CLVS.” On August 13, 2021, the last reported sale price of our common stock on the Nasdaq Global Select Market was $4.78 per share.

Sales of shares of our common stock, if any, under this prospectus supplement and the accompanying prospectus may be made in transactions that are deemed to be “at the market” offerings as defined in Rule 415 under the Securities Act of 1933, as amended, or the Securities Act, including sales made by means of ordinary brokers’ transactions, including directly on the Nasdaq Global Select Market or into any other existing trading market for our common stock, or sales made to or through a market maker, in block transactions or by any other method permitted by law, including privately negotiated transactions. Sales may be made at market prices prevailing at the time of a sale or at prices related to prevailing market prices or at negotiated prices. The Agents will act as sales agents and will use commercially reasonable efforts to sell on our behalf all of the shares of common stock requested to be sold by us, consistent with their normal trading and sales practices, on mutually agreed terms between the Agents and us. There is no arrangement for funds to be received in any escrow, trust or similar arrangement.

Under the distribution agreement, we may also sell shares of common stock to an Agent, as principal for its own account, at a price to be agreed upon at the time of sale. If we sell shares to an Agent as principal, we will enter into a separate terms agreement with such Agent, and we will describe the agreement in a separate prospectus supplement or pricing supplement.

The Agents will be entitled to compensation at a fixed commission rate of that will not exceed 3.0% of the gross sales price per share sold. In connection with the sale of shares of our common stock on our behalf, the Agents may be deemed to be “underwriters” within the meaning of the Securities Act and the compensation of the Agents may be deemed to be underwriting commissions. We have also agreed to provide indemnification and contribution to the Agents with respect to certain liabilities, including liabilities under the Securities Act. We refer you to “Plan of Distribution” beginning on page S-19 of this prospectus supplement for additional information regarding the compensation of the Agents.

Investing in our common stock involves risks. See “Risk Factors” beginning on page S-5 of this prospectus supplement and any other risk factors included in the accompanying prospectus and in the documents incorporated by reference in this prospectus supplement or the accompanying prospectus for a discussion of the factors you should carefully consider before deciding to purchase shares of our common stock.

Neither the Securities and Exchange Commission nor any state securities commission has approved or disapproved of these securities or passed upon the adequacy or accuracy of this prospectus supplement or the accompanying prospectus. Any representation to the contrary is a criminal offense.

J.P. Morgan BofA Securities

The date of this prospectus supplement is August 16, 2021.

TABLE OF CONTENTS

Prospectus Supplement

	Page
About this Prospectus Supplement		S-ii
Where You Can Find More Information		S-ii
Incorporation by Reference		S-iv
Prospectus Supplement Summary		S-1
Risk Factors		S-5
Cautionary Note on Forward-Looking Statements		S-7
Use of Proceeds		S-9
Dilution		S-10
Description of Common Stock		S-12
Material U.S. Federal Income and Estate Tax Considerations to Non-U.S. Holders		S-16
Plan of Distribution		S-19
Legal Matters		S-21
Experts		S-21

Prospectus

About this Prospectus	ii
Cautionary Note Regarding Forward-looking Statements	iii
About Clovis	1
Risk Factors	3
Use of Proceeds	4
Dilution	5
Securities We May Offer	6
Description of Capital Stock	7
Description of Warrants	11
Description of Debt Securities	12
Plan of Distribution	16
Legal Matters	19
Experts	19
Where You Can Find More Information	19
Incorporation By Reference	20

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ABOUT THIS PROSPECTUS SUPPLEMENT

This prospectus supplement and the accompanying prospectus dated May 7, 2021 are part of a registration statement, as amended, that we filed with the Securities and Exchange Commission, or the SEC, using a “shelf” registration process. Under this shelf registration process, we may from time to time offer to sell shares of common stock in one or more offerings. We provide information to you about this offering of shares of our common stock in two separate documents that are bound together: (1) this prospectus supplement, which describes the specific details regarding this offering; and (2) the accompanying prospectus, which provides general information, some of which may not apply to this offering. Generally, when we refer to this “prospectus,” we are referring to both documents combined. If information in this prospectus supplement is inconsistent with the accompanying prospectus, you should rely on this prospectus supplement. However, if any statement in one of these documents is inconsistent with a statement in another document having a later date—for example, a document incorporated by reference in the accompanying prospectus—the statement in the document having the later date modifies or supersedes the earlier statement as our business, financial condition, results of operations and prospects may have changed since the earlier dates. You should read this prospectus supplement, the accompanying prospectus, the documents and the information incorporated by reference in this prospectus supplement and the accompanying prospectus, and any free writing prospectus that we have authorized for use in connection with this offering when making your investment decision. You should also read and consider the information in the documents we have referred you to under the headings “Where You Can Find More Information” and “Incorporation by Reference.”

This prospectus supplement may not be used to consummate a sale of our common stock unless it is accompanied by the accompanying prospectus.

You should rely only on the information contained in or incorporated by reference in this prospectus supplement, the accompanying prospectus or any related free writing prospectus filed by us with the SEC. We have not authorized anyone to provide you with different information. This prospectus supplement and the accompanying prospectus do not constitute an offer to sell or the solicitation of an offer to buy our common stock other than our common stock described in this prospectus supplement or an offer to sell or the solicitation of an offer to buy our common stock in any circumstances in which such offer or solicitation is unlawful. You should assume that the information appearing in this prospectus supplement, the accompanying prospectus, the documents incorporated by reference and any related free writing prospectus is accurate only as of their respective dates. Our business, financial condition, results of operations and prospects may have changed materially since those dates.

Clovis Oncology^®, the Clovis logo and Rubraca^® are trademarks of Clovis Oncology, Inc. in the United States and in other selected countries. All other brand names or trademarks appearing in this prospectus supplement are the property of their respective holders. Unless the context requires otherwise, references in this prospectus supplement to “Clovis,” the “Company,” “we,” “us,” and “our” refer to Clovis Oncology, Inc. together with its consolidated subsidiaries.

WHERE YOU CAN FIND MORE INFORMATION

We file reports and proxy statements with the SEC. These filings include our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and proxy statements on Schedule 14A, as well as any amendments to those reports and proxy statements and are available free of charge through our website as soon as reasonably practicable after we file them with, or furnish them to, the SEC. Once at www.clovisoncology.com, go to Investors & News/SEC Filings to locate copies of such reports and proxy statements. Our website and the information contained on, or that can be accessed through, the website will not be deemed to be incorporated by reference in, and are not considered part of, this prospectus supplement or the accompanying prospectus. You should not rely on any such information in making your decision whether to

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purchase our securities. The SEC also maintains a website at www.sec.gov that contains reports, proxy and information statements and other information regarding us and other issuers that file electronically with the SEC.

We have filed with the SEC a registration statement on Form S-3 under the Securities Act relating to the securities being offered by this prospectus supplement. This prospectus supplement and the accompanying prospectus, which constitutes part of that registration statement, does not contain all of the information set forth in the registration statement or the exhibits and schedules which are part of the registration statement. For further information about us and the securities offered, see the registration statement and the exhibits and schedules thereto. Statements contained in this prospectus supplement or the accompanying prospectus regarding the contents of any contract or any other document to which reference is made are not necessarily complete, and, in each instance where a copy of a contract or other document has been filed as an exhibit to the registration statement, reference is made to the copy so filed, each of those statements being qualified in all respects by the reference.

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INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus supplement the information we file with the SEC in other documents, which means that we can disclose important information to you by referring you to those documents instead of having to repeat the information in this prospectus supplement. The information incorporated by reference is considered to be part of this prospectus supplement and the accompanying prospectus, and later information that we file with the SEC will automatically update and supersede such information. We incorporate by reference the documents listed below and any future information filed (rather than furnished) with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Securities Exchange Act of 1934, as amended, or the Exchange Act, between the date of this prospectus supplement and the date all securities to which this prospectus supplement relates have been sold or the offering is otherwise terminated, provided, however, that we are not incorporating any information furnished under Item 2.02 or Item 7.01 of any Current Report on Form 8-K:

• our Annual Report on  Form 10-K for the year ended December 31, 2020, as filed with the SEC on February 25, 2021;

• our Quarterly Reports on Form 10-Q  for the quarter ended March  31, 2021 and June 30, 2021, as filed with the SEC on May 5, 2021 and August 4, 2021, respectively;

• the information included in our Definitive Proxy Statement on  Schedule 14A, as filed with the SEC on April 28, 2021, to the extent incorporated by reference in Part III of our Annual Report on Form 10-K for the year ended December 31, 2020;

• our Current Report on Form 8-K, as filed with the SEC on  January 11, 2021  (only with respect to the Item 8.01 information), May  17, 2021, June 10, 2021 (as amended by Current Report on Form 8-K/A filed with the SEC on June  23, 2021) and July 13, 2021; and

• the description of our common stock contained in our registration statement on  Form 8-A, as filed with the SEC on November 10, 2011, as updated by  Exhibit 4.6 to our Annual Report on Form 10-K for the year ended December 31, 2020, including any amendments or reports filed for the purpose of updating the description.

We will furnish without charge to you a copy of any or all of the documents incorporated by reference, including exhibits to these documents, upon written or oral request. Direct your written request to: Investor Relations, Clovis Oncology, Inc., 5500 Flatiron Parkway, Suite 100, Boulder, Colorado 80301, or contact Investor Relations at (303) 625-5000.

A statement contained in a document incorporated by reference into this prospectus supplement and the accompanying prospectus shall be deemed to be modified or superseded for purposes of this prospectus supplement to the extent that a statement contained in this prospectus supplement, any other prospectus supplement or in any other subsequently filed document which is also incorporated in this prospectus supplement modifies or replaces such statement. Any statements so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus supplement or the accompanying prospectus.

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PROSPECTUS SUPPLEMENT SUMMARY

The following summary highlights information about us and this offering. This summary does not contain all of the information that may be important to you. You should read and carefully consider the following summary together with the entire prospectus supplement, the accompanying prospectus, the information incorporated by reference in this prospectus supplement and the accompanying prospectus, and any free writing prospectus that we have authorized for use in connection with this offering, before deciding to invest in our common stock. Some of the statements in this prospectus supplement constitute forward-looking statements that involve risks and uncertainties. See “Cautionary Note On Forward-Looking Statements.” Our actual results could differ materially from those anticipated in such forward-looking statements as a result of certain factors, including those discussed in the “Risk Factors” and other sections of this prospectus supplement.

About Clovis

We are a biopharmaceutical company focused on acquiring, developing and commercializing innovative anti-cancer agents in the United States, Europe and additional international markets. We target our development programs for the treatment of specific subsets of cancer populations, and simultaneously develop, with partners, for those indications that require them, diagnostic tools intended to direct a compound in development to the population that is most likely to benefit from its use.

Our marketed product Rubraca^® (rucaparib), an oral small molecule inhibitor of poly ADP-ribose polymerase, is marketed in the United States for two indications specific to recurrent epithelial ovarian, fallopian tube or primary peritoneal cancer and also an indication specific to metastatic castration-resistant prostate cancer (“mCRPC”). The initial indication received approval from the United States Food and Drug Administration (“FDA”) in December 2016 and covers the treatment of adult patients with deleterious BRCA (human genes associated with the repair of damaged DNA) mutation (germline and/or somatic)-associated epithelial ovarian, fallopian tube, or primary peritoneal cancer who have been treated with two or more chemotherapies and selected for therapy based on an FDA-approved companion diagnostic for Rubraca. In April 2018, the FDA also approved Rubraca for the maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy. The approval in this second, broader and earlier-line indication on a priority review timeline was based on positive data from the phase 3 ARIEL3 clinical trial. Diagnostic testing is not required for patients to be prescribed Rubraca in this maintenance treatment indication.

In May 2020, the FDA approved Rubraca for the treatment of adult patients with mCRPC associated with a deleterious BRCA mutation (germline and/or somatic) who have been treated previously with androgen receptor-directed therapy and a taxane-based chemotherapy and selected for therapy based on an FDA-approved companion diagnostic. The FDA approved this indication under accelerated approval based on objective response rate and duration of response data from the TRITON2 clinical trial. We launched Rubraca for this indication in the U.S. following receipt of the approval. As an accelerated approval, continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. The TRITON3 clinical trial is expected to serve as the confirmatory study for Rubraca’s approval in mCRPC.

In Europe, the European Commission granted a conditional marketing authorization in May 2018 for Rubraca as monotherapy treatment of adult patients with platinum-sensitive, relapsed or progressive, BRCA mutated (germline and/or somatic), high-grade epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have been treated with two or more prior lines of platinum-based chemotherapy, and who are unable to tolerate further platinum-based chemotherapy. In January 2019, the European Commission granted a variation to the marketing authorization to include the maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based

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chemotherapy. With this approval, Rubraca is authorized in Europe for certain patients in the recurrent ovarian cancer maintenance setting regardless of their BRCA mutation status. Following successful reimbursement negotiations, Rubraca has been launched in each of Germany, United Kingdom, Italy, France, Spain, the Netherlands and Switzerland.

Beyond our labeled indications, we have a clinical development program underway to further evaluate Rubraca in a variety of solid tumor types, either as monotherapy or in combination with other agents, including several studies as part of our ongoing clinical collaboration with Bristol Myers Squibb Company (“Bristol Myers Squibb”) to evaluate its immunotherapy Opdivo^® (nivolumab) in combination with Rubraca.

We hold worldwide rights to Rubraca.

Pursuant to our license and collaboration agreement with 3B Pharmaceuticals GmbH (“3BP”), entered into in September 2019, we have initiated development of a peptide-targeted radionuclide therapy and imaging agent targeting fibroblast-activating protein (“FAP”). We have completed sufficient preclinical work to support an investigational new drug application (“IND”) for the lead candidate under our license and collaboration agreement, designated internally as FAP-2286. Accordingly, we submitted two INDs for FAP-2286 for use as imaging and treatment agents in December 2020 to support an initial Phase 1 study to determine the dose, schedule and tolerability of FAP-2286 as a therapeutic agent with expansion cohorts planned in multiple tumor types as part of a global development program. The FDA cleared the two INDs and we have initiated the Phase 1 LuMIERE clinical study. LuMIERE is a Phase 1/2 study of 177Lu-FAP-2286 evaluating the compound in patients with advanced solid tumors. FAP-2286 labeled with gallium-68 (68Ga-FAP-2286) will be utilized to identify tumors that contain FAP for treatment in this study and once the recommended Phase 2 dose is determined, Phase 2 expansion cohorts are currently planned in five tumor types.

We hold U.S. and global rights to FAP-2286, excluding Europe (defined to include Russia, Turkey and Israel), where 3BP retains rights. We are also collaborating with 3BP on a discovery program directed to up to three additional, undisclosed targets for targeted radionuclide therapy, to which we would obtain global rights for any resulting product candidates.

Lucitanib, our product candidate currently in clinical development, is an investigational, oral, potent angiogenesis inhibitor which inhibits vascular endothelial growth factor receptors 1 through 3, platelet-derived growth factor receptors alpha and beta and fibroblast growth factor receptors 1 through 3. Lucitanib inhibits the same three pathways as Lenvima^® (lenvatinib), which has received an FDA approval for use in endometrial cancer in combination with Keytruda^® (pembrolizumab), a PD-1 inhibitor. We hold the global (excluding China) development and commercialization rights for lucitanib.

We were incorporated under the laws of the State of Delaware in April 2009. Our principal executive offices are located at 5500 Flatiron Parkway, Suite 100, Boulder, Colorado 80301, and our telephone number is (303) 625-5000. Our website address is www.clovisoncology.com. Our website and the information contained on, or that can be accessed through, the website will not be deemed to be incorporated by reference in, and are not considered part of, this prospectus supplement. You should not rely on any such information in making your decision whether to purchase our common stock.

Recent Developments

On May 17, 2021, we entered into a distribution agreement (the “Prior Distribution Agreement”) with the Agents pursuant to which we may offer and sell through the Agents shares of our common stock having an aggregate offering price of up to $75,000,000 in transactions that are deemed to be “at the market” offerings as defined in Rule 415(a)(4) under the Securities Act, including sales made by means of ordinary brokers’

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transactions, including directly on the Nasdaq Global Select Market or into any other existing trading market for the shares, or sales made to or through a market maker, in block transactions or by any other method permitted by law, including negotiated transactions. Sales may be made at market prices prevailing at the time of a sale or at prices related to prevailing market prices or at negotiated prices. During the period between May 18, 2021 and June 9, 2021, we sold an aggregate of 13,492,231 shares of our common stock under the Prior Distribution Agreement resulting gross proceeds of $74,999,995 and net proceeds to us of approximately $72.5 million, after deducting commissions and offering expenses, effectively closing out sales we may make pursuant to the Prior Distribution Agreement.

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The Offering

Common Stock Offered Up to $125,000,000 of common stock

Plan of Distribution Sales of shares of our common stock, if any, under this prospectus supplement and the accompanying prospectus may be made in transactions that are deemed to be “at the market” offerings as defined in Rule 415 under the Securities Act, including sales made by means of ordinary brokers’ transactions, including directly on the Nasdaq Global Select Market or into any other existing trading market for our common stock, or sales made to or through a market maker, in block transactions or by any other method permitted by law, including privately negotiated transactions. Sales may be made at market prices prevailing at the time of a sale or at prices related to prevailing market prices or at negotiated prices.

Use of Proceeds We anticipate that we will use the net proceeds from the sale of shares of our common stock offered under this prospectus supplement and accompanying prospectus for general corporate purposes, including funding of our development programs, sales and marketing expenses associated with Rubraca, repayment, repurchase or refinance of our debt obligations, payment of milestones pursuant to our license agreements, general and administrative expenses, acquisition or licensing of additional product candidates or businesses and working capital. See “Use of Proceeds” in this prospectus supplement for a more complete description of the intended use of proceeds from this offering.

Risk factors You should read the “Risk Factors” section of this prospectus supplement and the accompanying prospectus and in the documents incorporated by reference in this prospectus supplement and the accompanying prospectus for a discussion of factors you should carefully consider before deciding to invest in our common stock.

Nasdaq Global Select Market symbol Our common stock is listed on The Nasdaq Global Select Market under the symbol “CLVS.”

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RISK FACTORS

Investing in our common stock involves significant risks. Please see the risk factors below and under the heading “Risk Factors” in our most recently filed Annual Report on Form 10-K and Quarterly Reports on Form 10-Q, which are incorporated by reference in this prospectus supplement. Before making an investment decision, you should carefully consider these risks as well as other information we include or incorporate by reference in this prospectus supplement, including those described under “Cautionary Note On Forward-Looking Statements,” and the accompanying prospectus. The risks and uncertainties we have described are not the only ones facing our company. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business operations.

Risks Related to This Offering

If you purchase our common stock in this offering, you may incur immediate and substantial dilution in the book value of your shares.

Some or all of the public offering price per share in this offering may exceed the as adjusted net tangible book value per share of our outstanding common stock. After giving effect to an assumed sale of shares of common stock in the aggregate amount of $125,000,000 at an assumed public offering price of $4.78 per share, which was the last reported sale price per share of our common stock on the Nasdaq Global Select Market on August 13, 2021, and after deducting the commissions and estimated offering expenses payable by us, you would incur immediate and substantial dilution in the amount of $6.25 per share.

In addition, as of June 30, 2021, options to purchase 7,195,297 shares of our common stock at a weighted-average exercise price of $33.28 per share were outstanding, 4,253,667 shares of our common stock were issuable upon the vesting of restricted stock units, 1,041,098 shares of our common stock were issuable upon conversion of our 2.50% Convertible Senior Notes due September 15, 2021 (the “2021 Notes”), 3,938,340 shares of our common stock were issuable upon conversion of our 1.25% Convertible Senior Notes due 2025 (the “2025 Notes”), 11,771,117 shares of our common stock were issuable upon the conversion of our 4.50% Convertible Senior Notes due 2024 (the “Unrestricted 2024 Notes”) and 9,219,170 shares of our common stock were issuable upon conversion of our 4.50% Convertible Senior Notes due 2024 (the “Restricted 2024 Notes”). The exercise of any of these options, the issuance of common stock upon the vesting of these restricted stock units or the conversion of the outstanding notes would result in additional dilution. As a result of the dilution to investors purchasing shares in this offering, investors may receive significantly less than the purchase price paid in this offering, if anything, in the event of our liquidation. Further, because we will need to raise additional capital to develop our commercialization capabilities and fund our clinical development programs, we may in the future sell substantial amounts of common stock or securities convertible into or exchangeable for common stock. These future issuances of common stock or common stock-related securities, together with the exercise of outstanding options and any additional shares issued in connection with acquisitions, if any, may result in further dilution to investors. For a further description of the dilution that you will experience immediately after this offering, see “Dilution.”

We have broad discretion in the use of the net proceeds from this offering and may not use them effectively.

Our management will have broad discretion in the application of the net proceeds from this offering, and you will be relying on the judgment of our management regarding the application of these proceeds. You will not have the opportunity, as part of your investment decision, to assess whether the proceeds are being used appropriately. Our management might not apply our net proceeds in ways that ultimately increase the value of your investment. We anticipate that we will use the net proceeds of this offering for general corporate purposes, including funding of our development programs, sales and marketing expenses associated with Rubraca, repayment, repurchase or refinance of our debt obligations, payment of milestones pursuant to our license agreements, general and administrative expenses, acquisition or licensing of additional product candidates or

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businesses and working capital. Pending these uses, we may invest the net proceeds in short-term, interest-bearing investment grade securities, certificates of deposit or direct or guaranteed obligations of the U.S. government. These investments may not yield a favorable return to our stockholders. If we do not invest or apply the net proceeds from this offering, in ways that enhance stockholder value, we may fail to achieve expected financial results, which could cause our stock price to decline.

Shares of our common offered hereby may be sold in “at the market offerings,” or by other means as otherwise agreed by us and the Agents and investors who buy shares at different times will likely pay different prices.

Investors who purchase shares in this offering at different times will likely pay different prices, and so may experience different levels of dilution and different outcomes in their investment results. We will have discretion, subject to market demand, to vary the timing, prices, and numbers of shares sold in this offering. In addition, there is no minimum or maximum sales price for shares to be sold in this offering. Investors may experience a decline in the value of the shares they purchase in this offering as a result of sales made at prices lower than the prices they paid.

It is not possible to predict the actual number of shares of our common we will sell under the distribution agreement, or the gross proceeds resulting from those sales.

Subject to certain limitations in the distribution agreement and compliance with applicable law, we have the discretion to deliver a placement notice to a sales agent at any time throughout the term of the distribution agreement. The number of shares that are sold through a sales agent after delivering a placement notice will fluctuate based on a number of factors, including the market price of our common shares during the sales period, the limits we set with the sales agent in any applicable placement notice, and the demand for shares of our common stock during the sales period. Because the price per share of each share sold will fluctuate during the sales period, it is not currently possible to predict the number of shares of our common stock that will be sold or the gross proceeds to be raised in connection with those sales.

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CAUTIONARY NOTE ON FORWARD-LOOKING STATEMENTS

This prospectus supplement and the information incorporated herein by reference includes statements that are, or may be deemed, “forward-looking statements.” In some cases, these forward-looking statements can be identified by the use of forward-looking terminology, including the terms “believes,” “estimates,” “anticipates,” “expects,” “plans,” “intends,” “may,” “could,” “might,” “will,” “should,” “approximately” or, in each case, their negative or other variations thereon or comparable terminology, although not all forward-looking statements contain these words. They appear in a number of places throughout this prospectus supplement and include statements regarding our intentions, beliefs, projections, outlook, analyses or current expectations concerning, among other things, the market acceptance and commercial viability of our approved product, the development and performance of our sales and marketing capabilities, the performance of our clinical trial partners, third party manufacturers and our diagnostic partners, our ongoing and planned non-clinical studies and clinical trials, the timing of and our ability to make regulatory filings and obtain and maintain regulatory approvals for our product candidates, including our ability to confirm clinical benefit and safety of our approved product through confirmatory trials and other post-marketing requirements, the degree of clinical utility of our products, particularly in specific patient populations, expectations regarding clinical trial data, expectations regarding sales of our products, our results of operations, financial condition, liquidity, prospects, growth and strategies, the industry in which we operate, including our competition and the trends that may affect the industry or us.

By their nature, forward-looking statements involve risks and uncertainties because they relate to events, competitive dynamics and industry change and depend on the economic circumstances that may or may not occur in the future or may occur on longer or shorter timelines than anticipated. We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity and the development of the industry in which we operate may differ materially from the forward-looking statements contained herein.

Some of the factors that we believe could cause actual results to differ from those anticipated or predicted include:

• the impact of the COVID-19 pandemic on our revenues and our ability to continue to operate our business, including the timing and extent of any recovery;

• the need for substantial additional funding which may not be available to us on acceptable terms, or at all, and failure to obtain additional funding may impact our ability to continue our development programs and successfully commercialize Rubraca and to service our debt obligations;

• the rate and degree of market acceptance and commercial viability, including the safety, efficacy and potency of Rubraca and our other product candidates;

• if our sales, marketing and distribution capabilities for Rubraca or other product candidates for which we obtain marketing approval are inadequate, we may be unable to generate sufficient revenue from sales of our products;

• whether the Rubraca development program in other lines of therapies and indications will be successful or our other product candidates will receive regulatory approval;

• our expectations regarding the FDA and other regulatory authorities’ interpretation of our data and information on our product candidates and the impact on our business of the FDA’s and other regulatory authorities’ interpretation of our submissions, filing decisions by the FDA and other regulatory authorities, potential advisory committee meeting dates and advisory committee recommendations, and FDA and other regulatory authorities product approval decisions and related timelines;

• the success of competing drugs that are or become available;

• the success and timing of our non-clinical studies and clinical trials;

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• our ability to verify the clinical benefit of Rubraca through our confirmatory trials and to satisfy other post-marketing requirements and post-marketing commitments, our ability to obtain and maintain regulatory approval of Rubraca and our other product candidates, and the labeling under Rubraca and any other approval we may obtain;

• our ability to engage and retain third-party manufacturers with sufficient capability and capacity to support the commercialization of Rubraca and our other product candidates, and the performance of such third-party manufacturers;

• third-party payor coverage and reimbursement for Rubraca;

• our ability to obtain and maintain intellectual property protection for our product candidates, including our ability to defend our intellectual property against challenges;

• our ability to maintain our collaborations with our licensing partners to develop our product candidates;

• the size and growth of potential markets for our product candidates and our ability to serve those markets;

• the loss of key scientific or management personnel;

• regulatory developments in the United States and foreign countries;

• the accuracy of our estimates regarding expenses, future revenues, capital requirements and needs for additional financing; and

• our use of the proceeds from this offering and our ability to raise additional funds to support our business plans.

Any forward-looking statements that we make in this prospectus supplement speak only as of the date of such statement, and we undertake no obligation to update such statements to reflect events or circumstances after the date of this prospectus supplement or to reflect the occurrence of unanticipated events.

Please refer to the section entitled “Risk Factors” of this prospectus supplement, and any other risk factors set forth in the accompanying prospectus and in any information incorporated by reference in this prospectus supplement or the accompanying prospectus to better understand the risks and uncertainties inherent in our business and underlying any forward-looking statements, as well as any other risk factors and cautionary statements described in the documents we file from time to time with the SEC, specifically our most recent Annual Report on Form 10-K, our Quarterly Reports on Form 10-Q and our Current Reports on Form 8-K.

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USE OF PROCEEDS

The amount of proceeds we receive from this offering will depend upon the number of shares of common stock sold and the market price at which those shares are sold. There can be no assurance that we will be able to sell any shares of our common stock under or fully utilize the distribution agreement with the Agents as a source of financing. We anticipate that we will use the net proceeds of this offering for general corporate purposes, including funding of our development programs, sales and marketing expenses associated with Rubraca, repayment, repurchase or refinance of our debt obligations, payment of milestones pursuant to our license agreements, general and administrative expenses, acquisition or licensing of additional product candidates or businesses and working capital. Pending these uses, we may invest the net proceeds in short-term, interest-bearing investment grade securities, certificates of deposit or direct or guaranteed obligations of the U.S. government. We have not determined the amount of net proceeds to be used specifically for such purposes. As a result, management will retain broad discretion over the allocation of the net proceeds.

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DILUTION

If you invest in our common stock in this offering, your ownership interest will be diluted to the extent of the difference between the price per share of our common stock you pay to purchase your shares in this offering and the as adjusted net tangible book value per share of our common stock upon completion of this offering. Net tangible book value per share of our common stock is determined at any date by subtracting our total liabilities from the amount of our total tangible assets (total assets less intangible assets and related tax effects) and dividing the difference by the number of shares of our common stock deemed to be outstanding at that date.

Our historical net tangible book value as of June 30, 2021 was approximately $(333.1) million, or $(2.81) per share, based on 118,403,984 shares of common stock outstanding as of June 30, 2021.

After giving effect to our receipt of approximately $120.8 million of estimated net proceeds (after deducting estimated offering commissions and expenses payable by us) from our sale of common stock in this offering, assuming a public offering price of $4.78 per share, the last reported sale price of our common stock on the Nasdaq Global Select Market on August 13, 2021, our as adjusted net tangible book value as of June 30, 2021 would have been $(212.5) million, or $(1.47) per share. This amount would represent an immediate increase in net tangible book value of $1.34 per share of our common stock to existing stockholders and an immediate dilution in net tangible book value of $6.25 per share of our common stock to new investors purchasing shares of common stock in this offering.

The following table illustrates this dilution on a per share basis:

Assumed public offering price per share	$	4.78
Historical net tangible book value per share as of June 30, 2021		(2.81	)
As adjusted increase in net tangible book value per share attributable to investors participating in this offering		1.34
As adjusted net tangible book value per share after this offering		(1.47	)
Dilution of as adjusted net tangible book value per share to new investors	$	6.25

The table above illustrates that an aggregate of 26,150,627 shares of our common stock are sold at a price of $4.78 per share, the last reported sale price of our common stock on the Nasdaq Global Select Market on August 13, 2021. The shares of common stock sold in this offering, if any, will be sold from time to time at various prices. This information is supplied for illustrative purposes only.

The number of shares of our common stock to be outstanding immediately following this offering set forth above excludes:

• 7,195,297 shares of our common stock issuable upon the exercise of stock options outstanding as of June 30, 2021, at a weighted-average exercise price of $33.28 per share;

• 4,253,667 shares of our common stock issuable upon the vesting of restricted stock units outstanding as of June 30, 2021;

• 6,955,852 shares of our common stock reserved for future issuance under our 2020 Plan as of June 30, 2021;

• 3,000,000 shares of our common stock reserved for future issuance under our ESPP as of June 30, 2021;

• 1,041,098 shares of our common stock that may be issuable upon conversion of our 2021 Notes;

• 3,938,340 shares of our common stock that may be issuable upon conversion of our 2025 Notes;

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• 11,771,117 shares of our common stock that may be issuable upon conversion of our Unrestricted 2024 Notes; and

• 9,219,170 shares of our common stock that may be issuable upon the conversion of our Restricted 2024 Notes.

If (i) all our outstanding stock options had been exercised, assuming the treasury stock method, (ii) all of our shares of common stock underlying our restricted stock units were issued, and (iii) all of our convertible senior notes had been converted at their conversion rates, in each case as of June 30, 2021, our as adjusted net tangible book value would have been $1.73 per share, representing dilution in our as adjusted net tangible book value per share to new investors of $3.05.

Each $1.00 increase or decrease in the assumed public offering price of $4.78 per share, the last reported sale price of our common stock on the Nasdaq Global Select Market on August 13, 2021, assuming all of the shares of common stock in the aggregate amount of $125,000,000 are sold at that price, would decrease or increase the as adjusted net tangible book value per share by approximately $0.05 per share and $0.07 per share, respectively, and the dilution to investors purchasing shares in this offering by approximately $1.05 per share and $1.07 per share, respectively, assuming the dollar amount of shares offered by us, as set forth on the cover page of this prospectus supplement, remains the same and after deducting the estimated offering commissions and expenses payable by us.

In addition, we may choose to raise additional capital due to market conditions or strategic considerations even if we believe we have sufficient funds for our current or future operating plans. To the extent that we raise additional capital by issuing equity securities or convertible debt, your ownership will be further diluted.

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DESCRIPTION OF COMMON STOCK

The following summary describes our common stock. Because the following is only a summary, it does not contain all of the information that may be important to you. For a complete description, you should refer to our amended and restated certificate of incorporation, as amended (our “certificate of incorporation”) and amended and restated bylaws, as amended (our “bylaws”), copies of which are on file with the SEC. See “Where You Can Find More Information.”

The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders and are not entitled to cumulative votes with respect to the election of directors. The holders of common stock are entitled to receive dividends ratably, if, as and when dividends are declared from time to time by our board of directors out of legally available funds, after payment of dividends required to be paid on outstanding preferred stock, if any. Any decision to declare and pay dividends in the future will be made at the discretion of our board of directors and will depend on, among other things, our results of operations, cash requirements, financial condition, contractual restrictions and other factors that our board of directors may deem relevant. Upon our liquidation, dissolution or winding up, the holders of common stock are entitled to share ratably in all assets that are legally available for distribution after payment of all debts and other liabilities, subject to the prior rights of any holders of preferred stock then outstanding. The holders of common stock have no other preemptive, subscription, redemption, sinking fund or conversion rights. All outstanding shares of our common stock are fully paid and nonassessable. The shares of common stock to be issued upon closing of an offering will also be fully paid and nonassessable. The rights, preferences and privileges of holders of common stock are subject to, and may be negatively impacted by, the rights of the holders of shares of any series of preferred stock which we may designate and issue in the future.

Our certificate of incorporation authorizes us to issue up to 200 million shares of common stock, par value $0.001 per share. As of June 30, 2021, 118,403,984 shares of our common stock were outstanding.

As of June 30, 2021, options to purchase 7,195,297 shares of our common stock at a weighted-average exercise price of $33.28 per share were outstanding.

As of June 30, 2021, 4,253,667 shares of our common stock were issuable upon the vesting of restricted stock units outstanding.

As of June 30, 2021, 1,041,098 shares of our common stock were issuable upon conversion of our 2021 Notes, 3,938,340 shares of our common stock were issuable upon conversion of our 2025 Notes, 11,771,117 shares of our common stock were issuable upon the conversion of our Unrestricted 2024 Notes and 9,219,170 shares of our common stock were issuable upon conversion of our Restricted 2024 Notes.

Transfer Agent and Registrar

Our transfer agent and registrar for our common stock is Continental Stock Transfer & Trust Company.

Listing

Our common stock is listed on The Nasdaq Global Select Market under the symbol “CLVS.”

Registration Rights

Certain holders of our Restricted 2024 Notes are entitled to rights with respect to the registration under the Securities Act of the resale of the shares of common stock issuable upon the conversion of the Restricted 2024 Notes held by them, pursuant to which we filed a registration statement on November 4, 2020. Other than with respect to the foregoing, no holders of our securities are entitled to rights with respect to the registration of their securities under the Securities Act.

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Anti-Takeover Provisions of Delaware Law

We are subject to Section 203 of the Delaware General Corporation 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 the business combination or the transaction in which the person became an interested stockholder is approved in a prescribed manner. 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, in the case of affiliates or associates of the corporation, within three years prior to the determination of interested stockholder status, owned 15% or more of a corporation’s voting stock. The existence of this provision could have anti-takeover effects with respect to transactions not approved in advance by our board of directors, such as discouraging takeover attempts that might result in a premium over the market price of our common stock. The foregoing provisions of the Delaware General Corporation Law may have the effect of deterring or discouraging hostile takeovers or delaying changes in control of our company.

Charter and Bylaws Anti-Takeover Provisions

Classified Board of Directors

Our certificate of incorporation provides that our board of directors is divided into three classes of directors, with the number of directors in each class to be as nearly equal as possible. Our classified board of directors staggers terms of the three classes and has been implemented through one, two and three-year terms for the initial three classes, followed in each case by full three-year terms. With a classified board of directors, only one-third of the members of our board of directors is elected each year. This classification of directors has the effect of making it more difficult for stockholders to change the composition of our board of directors.

Size of Board of Directors and Removal of Directors

Our certificate of incorporation and bylaws provide that:

• the number of directors will be fixed from time to time exclusively pursuant to a resolution adopted by our board of directors, but must consist of not less than three directors, which will prevent stockholders from circumventing the provisions of our classified board of directors;

• directors may be removed only for cause; and

• vacancies on our board of directors may be filled only by a majority of directors then in office, even though less than a quorum, or by the sole remaining director, at any meeting of the board of directors.

Authorized Preferred Stock

Our certificate of incorporation provides for the issuance by our board of directors, without stockholder approval, of shares of preferred stock, with voting power, designations, preferences and other special rights as may be determined in the discretion of our board of directors. The issuance of preferred stock could decrease the amount of earnings and assets available for distribution to the holders of common stock or could adversely affect the rights and powers, including voting rights, of holders of common stock. In certain circumstances, such issuance could have the effect of decreasing the market price of the common stock. Preferred stockholders could also make it more difficult for a third party to acquire our company.

No Stockholder Action by Written Consent

Our certificate of incorporation and bylaws require that any action required or permitted to be taken by our stockholders must be effected at a duly called annual or special meeting of stockholders and may not be effected by a consent in writing.

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Calling of Special Meetings of Stockholders

Our bylaws provide that special stockholder meetings for any purpose may only be called by a majority of our board of directors, our chairman or our chief executive officer.

Advance Notice Requirements for Stockholder Proposals and Director Nominations

Our bylaws establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of stockholders, including proposed nominations of candidates for election to the board of directors. Stockholders at an annual meeting may only consider proposals or nominations specified in the notice of meeting or brought before the meeting by or at the direction of the board of directors, or by a stockholder of record on the record date for the meeting, who is entitled to vote at the meeting and who has delivered timely written notice in proper form to our secretary of the stockholder’s intention to bring such business before the meeting. These provisions could have the effect of delaying until the next stockholder meeting stockholder actions that are favored by the holders of a majority of our outstanding voting stock. These provisions also could discourage a third party from making a tender offer for our common stock, because even if it acquired a majority of our outstanding voting stock, it would be able to take action as a stockholder, such as electing new directors or approving a merger, only at a duly called stockholders meeting and not by written consent.

Exclusive Forum Charter Provision

Our certificate of incorporation provides that unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware shall be the sole and exclusive forum for (i) any derivative action or proceeding brought on our behalf, (ii) any action asserting a claim of breach of a fiduciary duty owed by any of our directors, officers, employees or agents to us or our stockholders, (iii) any action asserting a claim arising pursuant to any provision of the General Corporation Law of the State of Delaware or our certificate of incorporation or bylaws, or (iv) any action asserting a claim governed by the internal affairs doctrine, in each such case subject to said Court of Chancery having personal jurisdiction over the indispensable parties named as defendants therein. Any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock shall be deemed to have notice of and consented to this provision of our certificate of incorporation.

Our bylaws provide that unless we consent in writing to the selection of an alternative forum, the federal district courts of the United States of America shall be the sole and exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act. Any person or entity purchasing or otherwise acquiring or holding any interest in any of our securities shall be deemed to have notice of and consented to this provision of our bylaws.

The exclusive forum provision in our certificate of incorporation does not apply to suits brought to enforce any duty or liability created by the Exchange Act or any other claim for which the federal courts have exclusive jurisdiction. We note, however, that federal courts have concurrent jurisdiction over all suits brought to enforce any duty or liability created by the Securities Act. We note that the Supreme Court of the State of Delaware has recently decided that such exclusive forum provisions for causes of action arising under the Securities Act would be enforced under Delaware law and that investors cannot waive compliance with the federal securities laws and the rules and regulations thereunder. Although we believe this provision benefits us by providing increased consistency in the application of Delaware law in the types of lawsuits to which it applies, this provision may have the effect of discouraging lawsuits against our directors and officers.

Indemnification of Directors and Officers

Our certificate of incorporation and bylaws provide that we will, to the fullest extent permitted by Delaware corporate law, subject to certain limitations, indemnify any person made or threatened to be made a party to a proceeding by reason of that person’s former or present official capacity with us against judgments, penalties,

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fines, settlements and reasonable expenses. Any such person is also entitled, subject to certain limitations, to payment or reimbursement of reasonable expenses (including attorneys’ fees and disbursements and court costs) in advance of the final disposition of the proceeding.

The provision regarding indemnification of our directors and officers in our certificate of incorporation will generally not limit liability under state or federal securities laws.

We maintain a directors’ and officers’ insurance policy pursuant to which our directors and officers are insured against liability for actions taken in their capacities as directors and officers. We believe that these indemnification provisions and insurance are useful to attract and retain qualified directors and officers.

In addition, we have entered into indemnification agreements with each of our directors and named executive officers, which also provide, subject to certain exceptions, for indemnification for related expenses, including, among others, reasonable attorney’s fees, judgments, fines and settlements incurred in any action or proceeding. Your investment may be adversely affected to the extent that, in a class action or direct suit, we pay the costs of settlement and damage awards against directors and officers pursuant to these indemnification provisions.

Insofar as the foregoing provisions permit indemnification of directors, officers or persons controlling us for liability arising under the Securities Act, we have been informed that in the opinion of the SEC, this indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

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MATERIAL U.S. FEDERAL INCOME AND ESTATE TAX CONSIDERATIONS TO NON-U.S. HOLDERS

The following is a general discussion of the material U.S. federal income and estate tax consequences of the acquisition, ownership and disposition of our common stock, but is not a complete analysis of all the potential U.S. federal income and estate tax consequences relating thereto. Except where noted, this summary deals only with common stock that is purchased by a non-U.S. holder pursuant to this offering and is held as a capital asset by the non-U.S. holder within the meaning of Section 1221 of the U.S. Internal Revenue Code of 1986, as amended, or the Code. A “non-U.S. holder” means a beneficial owner of our common stock (other than a partnership) that is for U.S. federal income tax purposes any of the following:

• a nonresident alien individual;

• a corporation (or any other entity treated as a corporation for U.S. federal income tax purposes) created or organized in or under the laws of a jurisdiction other than the United States, any state thereof or the District of Columbia;

• an estate other than one the income of which is subject to U.S. federal income taxation regardless of its source; or

• a trust other than a trust that (A) is subject to the primary supervision of a court within the United States and the control of one or more U.S. persons having the authority to control all substantial decisions of the trust, or (B) has a valid election in effect to be treated as a U.S. person.

If an entity or arrangement treated as a partnership for U.S. federal income tax purposes holds our common stock, the U.S. federal income tax treatment of a partner will generally depend on the status of the partner and upon the activities of such partnership. Accordingly, partnerships that hold our common stock and the partners in such partnerships should consult their respective tax advisors with respect to the U.S. federal income and estate tax consequences of the ownership and disposition of our common stock.

For purposes of this discussion, a “non-U.S. holder” does not include an individual who is present in the United States for 183 days or more in the taxable year of disposition (where certain other requirements are met) and is not otherwise a resident of the United States for U.S. federal income tax purposes. Such an individual is urged to consult his or her tax advisor regarding the U.S. federal income and estate tax consequences of the ownership and disposition of our common stock.

This discussion does not address all aspects of U.S. federal income and estate taxation that may be relevant in light of a non-U.S. holder’s special tax status or particular circumstances. U.S. expatriates, “controlled foreign corporations,” “passive foreign investment companies,” corporations that accumulate earnings to avoid U.S. federal income tax, persons that hold common stock as part of a hedge, straddle or conversion transaction, persons subject to special tax accounting rules under Section 451(b) of the Code, financial institutions, insurance companies, brokers, dealers, traders, tax-exempt organizations and governmental organizations are among those categories of potential investors that may be subject to special rules not covered in this discussion. This discussion does not address any U.S. federal tax consequences other than income and estate tax consequences or any tax consequences arising under the laws of any state, local or non-U.S. taxing jurisdiction. Furthermore, the following discussion is based on current provisions of the Code, U.S. Treasury Regulations, or the Treasury Regulations, and administrative and judicial interpretations thereof, all as in effect on the date hereof, and all of which are subject to change, possibly with retroactive effect. Accordingly, each non-U.S. holder should consult its tax advisors regarding the U.S. federal, state, local and non-U.S. income, estate and other tax consequences of acquiring, holding and disposing of shares of our common stock.

THIS SUMMARY IS FOR GENERAL INFORMATION ONLY AND IS NOT TAX ADVICE. INVESTORS CONSIDERING THE PURCHASE OF OUR COMMON STOCK PURSUANT TO THIS OFFERING ARE ENCOURAGED TO CONSULT THEIR TAX ADVISORS REGARDING THE APPLICATION OF THE U.S. FEDERAL INCOME AND ESTATE TAX LAWS TO THEIR PARTICULAR

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SITUATIONS AND THE APPLICATION OF OTHER FEDERAL TAX LAWS, FOREIGN, STATE AND LOCAL LAWS, AND TAX TREATIES.

Distributions

Distributions in cash or other property on our common stock will constitute dividends for U.S. federal income tax purposes to the extent paid from our current or accumulated earnings and profits, as determined under U.S. federal income tax principles. Amounts not treated as dividends for U.S. federal income tax purposes will constitute a return of capital and will first be applied against and reduce a holder’s adjusted basis in the common stock, but not below zero, and then the excess, if any, will be treated as gain from the sale of the common stock, as described below.

We do not intend to pay cash dividends on our common stock for the foreseeable future. In the event that we do make distributions on our common stock, subject to the discussion below on effectively connected income, amounts paid to a non-U.S. holder of common stock that are treated as dividends for U.S. federal income tax purposes generally will be subject to U.S. withholding tax at a rate of 30% of the gross amount of the dividends or such lower rate as may be specified by an applicable income tax treaty. In order to receive a reduced income tax treaty rate, a non-U.S. holder generally must provide a valid Internal Revenue Service, or IRS, Form W-8BEN-E or W-8BEN or other successor form certifying qualification for the reduced rate. A non-U.S. holder that does not timely furnish the required documentation, but that qualifies for a reduced treaty rate, may obtain a refund of any excess amounts withheld by timely filing an appropriate claim for refund with the IRS.

Dividends received by a non-U.S. holder that are effectively connected with a U.S. trade or business conducted by the non-U.S. holder (and, if required by an applicable income tax treaty, are attributable to a U.S. permanent establishment) are exempt from such withholding tax. In order to obtain this exemption, a non-U.S. holder must provide the applicable withholding agent with a valid IRS Form W-8ECI or other applicable form properly certifying such exemption. Such effectively connected dividends, although not subject to withholding tax, will generally be subject to regular U.S. federal income tax as if the non-U.S. holder were a U.S. resident, unless an applicable income tax treaty provides otherwise. Non-U.S. holders taxed as corporations that receive effectively connected dividends may also be subject to an additional “branch profits tax” imposed at a rate of 30% (or a lower income tax treaty rate) on the effectively connected dividends, as adjusted for certain items.

Gain on Disposition of Common Stock

A non-U.S. holder generally will not be subject to U.S. federal income tax on any gain realized upon the sale or other disposition of our common stock unless:

• the gain is “effectively connected” with the non-U.S. holder’s conduct of a trade or business in the United States (and, if required by an applicable income tax treaty, is attributable to a U.S. permanent establishment); or

• our common stock constitutes a U.S. real property interest by reason of our status as a U.S. real property holding corporation for U.S. federal income tax purposes.

Unless an applicable income tax treaty provides otherwise, gain described in the first bullet point above generally will be subject to regular U.S. federal income tax as if the non-U.S. holder were a U.S. resident and, in the case of non-U.S. holders taxed as corporations, the branch profits tax described above.

Generally, a corporation is a U.S. real property holding corporation, or USRPHC, if the fair market value of its U.S. real property interests, as defined in the Code and applicable Treasury Regulations, equals or exceeds 50% of the aggregate fair market value of its worldwide real property interests and its other assets used or held for use in a trade or business.

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We believe that we are not, and currently do not anticipate becoming, a USRPHC. However, there can be no assurance that our current analysis is correct or that we will not become a USRPHC in the future. Even if we are or become a USRPHC, as long as our common stock is “regularly traded on an established securities market,” within the meaning of applicable Treasury Regulations, such common stock will be treated as U.S. real property interests only if the non-U.S. holder actually or constructively held more than 5% of such regularly traded common stock at some time during the shorter of the five year period preceding the disposition or the non-U.S. holder’s holding period.

Backup Withholding and Information Reporting

Information returns will be filed with the IRS in connection with payments of dividends and may be filed with the IRS in connection with the proceeds from a sale or other disposition of common stock. A non-U.S. holder may have to comply with certification procedures to establish that it is not a U.S. person in order to avoid certain information reporting and backup withholding requirements. The certification procedures required to claim a reduced rate of withholding under an income tax treaty generally will satisfy the certification requirements necessary to avoid backup withholding, as well. The amount of any backup withholding from a payment to a non-U.S. holder will be allowed as a credit against its U.S. federal income tax liability and may entitle it to a refund, provided that the required information is timely furnished to the IRS. Copies of these information returns may also be made available under the provisions of a specific treaty or agreement to the tax authorities of the country in which the non-U.S. holder resides or is established.

U.S. Federal Estate Tax

Shares of common stock held (or deemed held) by an individual who is a non-U.S. holder at the time of his or her death will be included in such non-U.S. holder’s gross estate for U.S. federal estate tax purposes, unless an applicable estate tax treaty provides otherwise.

Additional Withholding Requirements

Pursuant to Sections 1471 through 1474 of the Code, or FATCA, U.S. tax may be withheld at the rate of 30% on payments of dividends on our common stock to non-U.S. financial institutions and certain other foreign non-financial entities unless such foreign entities satisfy certain reporting requirements or certification requirements, unless a relevant exemption applies. Foreign financial institutions located in jurisdictions that have an intergovernmental agreement with the United States governing FATCA may be subject to different rules. The U.S. Treasury Department has issued proposed Treasury Regulations that, if finalized in their present form, would eliminate withholding under FATCA with respect to gross proceeds from a sale or other disposition of our common stock. The preamble to such proposed regulations states that taxpayers may generally rely upon the proposed Treasury Regulations until final regulations are issued. Prospective holders of our common stock are encouraged to consult with their own tax advisors regarding the possible implications of FATCA on an investment in our common stock.

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PLAN OF DISTRIBUTION

We have entered into a distribution agreement with the Agents relating to shares of our common stock offered by this prospectus supplement and the accompanying prospectus. In accordance with the terms of the distribution agreement, we may offer and sell from time to time shares of our common stock having an aggregate gross offering price of up to $125,000,000 through the Agents, acting as our agents or principals.

Sales of shares of our common stock, if any, under this prospectus supplement and the accompanying prospectus may be made in transactions that are deemed to be “at the market” offerings as defined in Rule 415 under the Securities Act, including sales made by means of ordinary brokers’ transactions, including directly on the Nasdaq Global Select Market or into any other existing trading market for our common stock, or sales made to or through a market maker, in block transactions or by any other method permitted by law, including privately negotiated transactions. Sales may be made at market prices prevailing at the time of a sale or at prices related to prevailing market prices or at negotiated prices. The shares of our common stock to which this prospectus supplement and the accompanying prospectus relate will be sold only through one Agent on any given day.

We will designate the maximum amount of common stock to be sold through an Agent on a daily basis or otherwise as we and the applicable Agent agree and the minimum price per share at which such common stock may be sold. No Agent is required to sell any specific dollar amount of shares. Subject to the terms and conditions of the distribution agreement, the applicable Agent will use its commercially reasonable efforts consistent with its normal trading and sales practices to sell on our behalf all of the designated shares of common stock. We may instruct an Agent not to sell any common stock if the sales cannot be effected at or above the price designated by us in any such instruction. We or any Agent, with respect to itself only, may suspend the offering of our common stock by notifying the other party.

The applicable Agent will provide to us written confirmation before the open of trading on the Nasdaq Global Select Market on the day following each day on which shares of common stock are sold under the distribution agreement. Each confirmation will include the number of shares of common stock sold on such day, the gross sales proceeds and the compensation payable by us to such Agent. We will report at least quarterly the number of shares of common stock sold through the Agents under the distribution agreement, the net proceeds to us (before expenses) and the aggregate compensation paid by us to the Agents in connection with the sales of the shares of common stock.

Each Agent will be entitled to compensation in an amount not to exceed 3.0% of the gross sales price per share for any shares of our common stock sold through it, as Agent. We have also agreed to reimburse the Agents for certain of their expenses depending on the amount of securities sold pursuant to this prospectus supplement and the accompanying prospectus, in an amount not to exceed $100,000.

Under the terms of the distribution agreement, we may also sell shares of our common stock to each of the Agents, as principal for its own respective account, at a price to be agreed upon at the time of sale. If we sell shares to an Agent, as principal, we will enter into a separate agreement with that Agent, setting forth the terms of such transaction, and we will describe the agreement in a separate prospectus supplement or pricing supplement.

Settlement of any sales of common stock will occur, unless the parties agree otherwise, on the second business day following the date on which such sales were made (or such earlier day as is industry practice for regular-way trading). There is no arrangement for funds to be received in an escrow, trust or similar arrangement. Sales of our common stock as contemplated in this prospectus supplement will be settled through the facilities of The Depository Trust Company or by such other means as we and the applicable Agent may agree.

The offering of our common stock pursuant to the distribution agreement will terminate upon the earlier of the (i) sale of all of our shares of common stock subject to the distribution agreement, (ii) termination of the

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distribution agreement by us or by the Agents as provided therein and (iii) the eighteen-month anniversary of the date of the distribution agreement. In connection with the sale of the shares of common stock on our behalf, each of the Agents may be deemed to be an “underwriter” within the meaning of the Securities Act and the compensation paid to each of the Agents may be deemed to be underwriting commissions or discounts.

We have agreed to provide indemnification and contribution to the Agents against certain liabilities, including civil liabilities under the Securities Act.

We estimate that the total expenses of the offering payable by us, excluding commissions payable to the Agents under the distribution agreement, will be approximately $400,000.

The Agents and their respective affiliates are full service financial institutions engaged in various activities, which may include sales and trading, commercial and investment banking, advisory, investment management, investment research, principal investment, hedging, market making, brokerage and other financial and non-financial activities and services. Certain of the Agents and their respective affiliates have engaged, and may in the future engage, in investment banking, commercial banking and other financial advisory and commercial dealings with us and our affiliates. In addition, an affiliate of J.P. Morgan Securities LLC is a letter of credit issuer under our letters of credit. We may use a portion of the net proceeds from the offering to repay amounts outstanding under such letters of credit from time to time. To the extent we use proceeds from this offering to repay indebtedness under our letters of credit, such affiliate may receive a portion of the net proceeds from this offering.

In addition, in the ordinary course of their business activities, the Agents and their respective affiliates may make or hold a broad array of investments and actively trade debt and equity securities (or related derivative securities) and financial instruments (including bank loans) for their own account and for the accounts of their customers. Such investments and securities activities may involve securities and/or instruments of ours or our affiliates. The Agents and their respective affiliates may also make investment recommendations and/or publish or express independent research views in respect of such securities or financial instruments and may hold, or recommend to clients that they acquire, long and/or short positions in such securities and instruments.

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LEGAL MATTERS

The validity of the shares of our common stock offered by this prospectus supplement will be passed upon for us by Willkie Farr & Gallagher LLP, New York, New York. Certain legal matters in connection with this offering will be passed upon for the Agents by Latham & Watkins LLP, San Diego, California.

EXPERTS

The consolidated financial statements of Clovis Oncology, Inc. appearing in Clovis Oncology, Inc.’s Annual Report (Form 10-K) for the year ended December 31, 2020, and the effectiveness of Clovis Oncology, Inc.’s internal control over financial reporting as of December 31, 2020, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, included therein, and incorporated herein by reference. Such financial statements are, and audited financial statements to be included in subsequently filed documents will be, incorporated herein in reliance upon the reports of Ernst & Young LLP pertaining to such financial statements and the effectiveness of our internal control over financial reporting as of the respective dates (to the extent covered by consents filed with the Securities and Exchange Commission) given on the authority of such firm as experts in accounting and auditing.

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Prospectus

$200,000,000

COMMON STOCK

PREFERRED STOCK

WARRANTS

DEBT SECURITIES

We may issue from time to time in one or more series or classes up to $200,000,000 in aggregate total amount of our common stock, preferred stock, warrants and/or debt securities. This prospectus describes the general terms of our common stock, preferred stock, warrants and debt securities and the general manner in which such securities will be offered. We will describe the specific manner in which these securities will be offered in supplements to this prospectus, which may also supplement, update or amend information contained in this prospectus. You should read this prospectus, any applicable prospectus supplement, any free writing prospectus and any term sheet or other offering materials carefully before you invest in our securities.

We may offer our securities in amounts, at prices and on terms determined at the time of offering. The securities may be sold directly to you, through agents, or through underwriters and dealers. If agents, underwriters or dealers are used to sell the shares, we will name them and describe their compensation in a prospectus supplement.

Our common stock is listed on The Nasdaq Global Select Market under the symbol “CLVS.” On February 24, 2021, the last reported sale price of our common stock on The Nasdaq Global Select Market was $6.20 per share.

Investing in our securities involves risks. See “Risk Factors” beginning on page 3 of this prospectus and any other risk factors included in any accompanying prospectus supplement and in the documents incorporated by reference in this prospectus or any prospectus supplement for a discussion of the factors you should carefully consider before deciding to purchase our securities.

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

The date of this prospectus is May 7, 2021

TABLE OF CONTENTS

ABOUT THIS PROSPECTUS	ii
CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS	iii
ABOUT CLOVIS	1
RISK FACTORS	3
USE OF PROCEEDS	4
DILUTION	5
SECURITIES WE MAY OFFER	6
DESCRIPTION OF CAPITAL STOCK	7
DESCRIPTION OF WARRANTS	11
DESCRIPTION OF DEBT SECURITIES	12
PLAN OF DISTRIBUTION	16
LEGAL MATTERS	19
EXPERTS	19

i

ABOUT THIS PROSPECTUS

This prospectus is part of a registration statement that we filed with the Securities and Exchange Commission, or the SEC, using a “shelf” registration process. Under this shelf process, we may from time to time offer to sell up to $200,000,000 in aggregate total amount of our shares of common stock, preferred stock, warrants to purchase any such securities and debt securities in one or more offerings.

This prospectus provides you with a general description of the securities we may offer. Each time we offer a type or series of such securities, we will provide a prospectus supplement that will contain specific information about the terms of that offering. The prospectus supplement, or information incorporated by reference in this prospectus or any prospectus supplement that is of a more recent date, may also add, update or change information contained in this prospectus. To the extent that any statement that we make in a prospectus supplement is inconsistent with statements made in this prospectus, the statements made in this prospectus will be deemed modified or superseded by those made in the prospectus supplement. You should read both this prospectus and any prospectus supplement together with the additional information described below under the heading “Where You Can Find More Information.” This prospectus may not be used to consummate a sale of our securities unless it is accompanied by a prospectus supplement. We may also authorize one or more free writing prospectuses to be provided to you that may contain material information relating to these offerings.

You should rely only on the information contained in or incorporated by reference in this prospectus, any accompanying prospectus supplement or in any related free writing prospectus filed by us with the SEC. We have not authorized anyone to provide you with different information. This prospectus and any accompanying prospectus supplement do not constitute an offer to sell or the solicitation of an offer to buy our securities other than our securities described in such accompanying prospectus supplement or an offer to sell or the solicitation of an offer to buy our securities in any circumstances in which such offer or solicitation is unlawful. You should assume that the information appearing in this prospectus, any prospectus supplement, the documents incorporated by reference and any related free writing prospectus is accurate only as of their respective dates. Our business, financial condition, results of operations and prospects may have changed materially since those dates. Any information in subsequent filings incorporated by reference in this prospectus or any accompanying prospectus supplement that is inconsistent with this prospectus or any accompanying prospectus supplement will supersede the information in this prospectus or any accompanying prospectus supplement.

Clovis Oncology^®, the Clovis logo and Rubraca^TM are trademarks of Clovis Oncology, Inc. in the United States and in other selected countries. All other brand names or trademarks appearing in this prospectus are the property of their respective holders. Unless the context requires otherwise, references in this prospectus to “Clovis,” the “Company,” “we,” “us,” and “our” refer to Clovis Oncology, Inc., together with its consolidated subsidiaries.

In this prospectus, we refer to the common stock, preferred stock, warrants and debt securities being offered, collectively, as “securities.”

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CAUTIONARY NOTE REGARDING FORWARD-LOOKING STATEMENTS

This prospectus and the information incorporated herein by reference includes statements that are, or may be deemed, “forward-looking statements.” In some cases, these forward-looking statements can be identified by the use of forward-looking terminology, including the terms “believes,” “estimates,” “anticipates,” “expects,” “plans,” “intends,” “may,” “could,” “might,” “will,” “should,” “approximately” or, in each case, their negative or other variations thereon or comparable terminology, although not all forward-looking statements contain these words. They appear in a number of places throughout this prospectus and include statements regarding our intentions, beliefs, projections, outlook, analyses or current expectations concerning, among other things, the market acceptance and commercial viability of our approved product, the development and performance of our sales and marketing capabilities, the performance of our clinical trial partners, third party manufacturers and our diagnostic partners, our ongoing and planned non-clinical studies and clinical trials, the timing of and our ability to make regulatory filings and obtain and maintain regulatory approvals for our product candidates, including our ability to confirm clinical benefit and safety of our approved product through confirmatory trials and other post-marketing requirements, the degree of clinical utility of our products, particularly in specific patient populations, expectations regarding clinical trial data, expectations regarding sales of our products, our results of operations, financial condition, liquidity, prospects, growth and strategies, the industry in which we operate, including our competition and the trends that may affect the industry or us.

By their nature, forward-looking statements involve risks and uncertainties because they relate to events, competitive dynamics and industry change and depend on the economic circumstances that may or may not occur in the future or may occur on longer or shorter timelines than anticipated. We caution you that forward-looking statements are not guarantees of future performance and that our actual results of operations, financial condition and liquidity and the development of the industry in which we operate may differ materially from the forward-looking statements contained herein.

Any forward-looking statements that we make in this prospectus speak only as of the date of such statement, and we undertake no obligation to update such statements to reflect events or circumstances after the date of this prospectus or to reflect the occurrence of unanticipated events.

Please refer to the section entitled “Risk Factors” of this prospectus, and any other risk factors set forth in any accompanying prospectus supplement and in any information incorporated by reference in this prospectus or any accompanying prospectus supplement to better understand the risks and uncertainties inherent in our business and underlying any forward-looking statements, as well as any other risk factors and cautionary statements described in the documents we file from time to time with the SEC, specifically our most recent Annual Report on Form 10-K, our Quarterly Reports on Form 10-Q and our Current Reports on Form 8-K.

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ABOUT CLOVIS

We are a biopharmaceutical company focused on acquiring, developing and commercializing innovative anti-cancer agents in the United States, Europe and additional international markets. We target our development programs for the treatment of specific subsets of cancer populations, and simultaneously develop, with partners, for those indications that require them, diagnostic tools intended to direct a compound in development to the population that is most likely to benefit from its use.

Our marketed product Rubraca^® (rucaparib), an oral small molecule inhibitor of poly ADP-ribose polymerase, is marketed in the United States for two indications specific to recurrent epithelial ovarian, fallopian tube or primary peritoneal cancer and also an indication specific to metastatic castration-resistant prostate cancer (“mCRPC”). The initial indication received approval from the United States Food and Drug Administration (“FDA”) in December 2016 and covers the treatment of adult patients with deleterious BRCA (human genes associated with the repair of damaged DNA) mutation (germline and/or somatic)-associated epithelial ovarian, fallopian tube, or primary peritoneal cancer who have been treated with two or more chemotherapies and selected for therapy based on an FDA-approved companion diagnostic for Rubraca. In April 2018, the FDA also approved Rubraca for the maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy. The approval in this second, broader and earlier-line indication on a priority review timeline was based on positive data from the phase 3 ARIEL3 clinical trial. Diagnostic testing is not required for patients to be prescribed Rubraca in this maintenance treatment indication.

In May 2020, the FDA approved Rubraca for the treatment of adult patients with mCRPC associated with a deleterious BRCA mutation (germline and/or somatic) who have been treated previously with androgen receptor-directed therapy and a taxane-based chemotherapy. The FDA approved this indication under accelerated approval based on objective response rate and duration of response data from the TRITON2 clinical trial. We launched Rubraca for this indication in the U.S. following receipt of the approval. As an accelerated approval, continued approval for this indication may be contingent upon verification and description of clinical benefit in confirmatory trials. The TRITON3 clinical trial is expected to serve as the confirmatory study for Rubraca’s approval in mCRPC. In August 2020, the FDA approved the use of Foundation Medicine’s blood-based diagnostic test, FoundationOne Liquid CDx, as a companion diagnostic for the detection of deleterious BRCA mutation (germline and/or somatic) to select mCRPC patients for treatment with Rubraca.

In Europe, the European Commission granted a conditional marketing authorization in May 2018 for Rubraca as monotherapy treatment of adult patients with platinum-sensitive, relapsed or progressive, BRCA mutated (germline and/or somatic), high-grade epithelial ovarian, fallopian tube, or primary peritoneal cancer, who have been treated with two or more prior lines of platinum-based chemotherapy, and who are unable to tolerate further platinum-based chemotherapy. In January 2019, the European Commission granted a variation to the marketing authorization to include the maintenance treatment of adult patients with recurrent epithelial ovarian, fallopian tube, or primary peritoneal cancer who are in a complete or partial response to platinum-based chemotherapy. With this approval, Rubraca is authorized in Europe for certain patients in the recurrent ovarian cancer maintenance setting regardless of their BRCA mutation status. Following successful reimbursement negotiations, Rubraca has been launched in each of Germany, United Kingdom, Italy, France, Spain and the Netherlands, and reimbursement is pending in Switzerland.

Beyond our labeled indications, we have a clinical development program underway to further evaluate Rubraca in a variety of solid tumor types, either as monotherapy or in combination with other agents, including several studies as part of our ongoing clinical collaboration with Bristol Myers Squibb Company (“Bristol Myers Squibb”) to evaluate its immunotherapy Opdivo^® (nivolumab) in combination with Rubraca.

We hold worldwide rights to Rubraca.

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Pursuant to our license and collaboration agreement with 3B Pharmaceuticals GmbH (“3BP”), entered into in September 2019, we have initiated development of a peptide-targeted radionuclide therapy and imaging agent targeting fibroblast-activating protein (“FAP”). We have completed sufficient preclinical work to support an investigational new drug application (“IND”) for the lead candidate under our license and collaboration agreement, designated internally as FAP-2286. Accordingly, we submitted two INDs for FAP-2286 for use as imaging and treatment agents in December 2020 to support an initial Phase 1 study to determine the dose and tolerability of FAP-2286 as a therapeutic agent with expansion cohorts planned in multiple tumor types as part of a global development program.

We hold U.S. and global rights to FAP-2286, excluding Europe (defined to include Russia, Turkey and Israel), where 3BP retains rights. We are also collaborating with 3BP on a discovery program directed to up to three additional, undisclosed targets for targeted radionuclide therapy, to which we would obtain global rights for any resulting product candidates.

Lucitanib, our second product candidate currently in clinical development, is an investigational, oral, potent angiogenesis inhibitor which inhibits vascular endothelial growth factor receptors 1 through 3, platelet-derived growth factor receptors alpha and beta and fibroblast growth factor receptors 1 through 3. Lucitanib inhibits the same three pathways as Lenvima^® (lenvatinib), which has received an FDA approval for use in endometrial cancer in combination with Keytruda^® (pembrolizumab), a PD-1 inhibitor. This, together with preclinical data for lucitanib in combination with a PD-1 inhibitor that demonstrated enhanced anti-tumor activity compared to that of single agents, represent a scientific rationale for development of lucitanib in combination with a PD-1 inhibitor, and in February 2019, lucitanib was added to our clinical collaboration with Bristol Myers Squibb. We hold the global (excluding China) development and commercialization rights for lucitanib.

We were incorporated under the laws of the State of Delaware in April 2009. Our principal executive offices are located at 5500 Flatiron Parkway, Suite 100, Boulder, Colorado 80301, and our telephone number is (303) 625-5000. Our website address is www.clovisoncology.com. Our website and the information contained on, or that can be accessed through, the website will not be deemed to be incorporated by reference in, and are not considered part of, this prospectus. You should not rely on any such information in making your decision whether to purchase our securities.

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RISK FACTORS

Investing in our securities involves significant risks. Please see the risk factors under the heading “Risk Factors” in our most recently filed Annual Report on Form 10-K, as revised or supplemented by our Quarterly Reports on Form 10-Q filed with the SEC since the filing of our most recent Annual Report on Form 10-K, all of which are incorporated by reference in this prospectus. Before making an investment decision, you should carefully consider these risks as well as other information we include or incorporate by reference in this prospectus and any prospectus supplement. The risks and uncertainties we have described are not the only ones facing our company. Additional risks and uncertainties not presently known to us or that we currently deem immaterial may also affect our business operations.

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USE OF PROCEEDS

Unless otherwise indicated in any applicable prospectus supplement, we intend to use the net proceeds from the sale of any securities offered under this prospectus for general corporate purposes, including funding of our development programs, sales and marketing expenses associated with Rubraca, repayment, repurchase or refinance of other debt obligations, payment of milestones pursuant to our license agreements, general and administrative expenses, acquisition or licensing of additional product candidates or businesses and working capital. Pending these uses, we may invest the net proceeds in short-term, interest-bearing investment grade securities, certificates of deposit or direct or guaranteed obligations of the U.S. government. We have not determined the amount of net proceeds to be used specifically for such purposes. As a result, management will retain broad discretion over the allocation of net proceeds.

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DILUTION

If there is a material dilution of the purchasers’ equity interest from the sale of our securities offered under this prospectus, we will set forth in any prospectus supplement the following information regarding any such material dilution of the equity interests of purchasers purchasing our securities in an offering under this prospectus:

• the net tangible book value per share of our securities before and after the offering;

• the amount of the increase in such net tangible book value per share attributable to the cash payments made by the purchasers in the offering; and

• the amount of the immediate dilution from the public offering price which will be absorbed by such purchasers.

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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 under this prospectus. The terms of the offering of securities, the initial offering price and the net proceeds to us will be contained in the prospectus supplement, and other offering material, relating to such offer. 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.

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DESCRIPTION OF CAPITAL STOCK

The following summary describes our capital stock and the material provisions of our amended and restated certificate of incorporation, as amended (our “certificate of incorporation”), and our amended and restated bylaws, as amended (our “bylaws”), and certain provisions of the Delaware General Corporation Law. Because the following is only a summary, it does not contain all of the information that may be important to you. For a complete description, you should refer to our certificate of incorporation and bylaws, copies of which are on file with the SEC. See “Where You Can Find More Information.”

General

Our certificate of incorporation authorizes us to issue up to 200 million shares of common stock, par value $0.001 per share, and 10 million shares of preferred stock, par value $0.001 per share.

Common Stock

The holders of our common stock are entitled to one vote for each share held of record on all matters submitted to a vote of stockholders and are not entitled to cumulative votes with respect to the election of directors. The holders of common stock are entitled to receive dividends ratably, if, as and when dividends are declared from time to time by our board of directors out of legally available funds, after payment of dividends required to be paid on outstanding preferred stock, if any. Any decision to declare and pay dividends in the future will be made at the discretion of our board of directors and will depend on, among other things, our results of operations, cash requirements, financial condition, contractual restrictions and other factors that our board of directors may deem relevant. Upon our liquidation, dissolution or winding up, the holders of common stock are entitled to share ratably in all assets that are legally available for distribution after payment of all debts and other liabilities, subject to the prior rights of any holders of preferred stock then outstanding. The holders of common stock have no other preemptive, subscription, redemption, sinking fund or conversion rights. All outstanding shares of our common stock are fully paid and nonassessable. The shares of common stock to be issued upon closing of an offering will also be fully paid and nonassessable. The rights, preferences and privileges of holders of common stock are subject to, and may be negatively impacted by, the rights of the holders of shares of any series of preferred stock which we may designate and issue in the future.

As of December 31, 2020, 103,699,109 shares of our common stock were outstanding.

As of December 31, 2020, options to purchase 6,500,669 shares of our common stock at a weighted average exercise price of $37.79 per share were outstanding.

As of December 31, 2020, 2,963,547 shares of our common stock were issuable upon the vesting of restricted stock units outstanding.

As of December 31, 2020, 1,041,098 shares of our common stock were issuable upon conversion of our 2.50% Convertible Senior Notes due 2021, 3,938,340 shares of our common stock were issuable upon the conversion of our 1.25% Convertible Senior Notes due 2025, 11,771,117 shares of our common stock were issuable upon the conversion of our 4.50% Convertible Senior Notes due 2024 (the “Unrestricted 2024 Notes”) and 9,219,170 shares of our common stock were issuable upon the conversion of our 4.50% Convertible Senior Notes due 2024 (the “Restricted 2024 Notes”).

Transfer Agent and Registrar

Our transfer agent and registrar for our common stock is Continental Stock Transfer & Trust Company.

Listing

Our common stock is listed on The Nasdaq Global Select Market under the symbol “CLVS.”

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Preferred Stock

Under our certificate of incorporation, our board of directors has the authority, without action by our stockholders, to designate and issue up to 10 million shares of preferred stock, par value $0.001 per share, in one or more series and to designate the rights, preferences and privileges of each series, any or all of which may be greater than the rights of our common stock. It is not possible to state the actual effect of the issuance of any shares of preferred stock upon the rights of holders of our common stock until our board of directors determines the specific rights of the holders of preferred stock. However, the effects might include, among other things, restricting dividends on the common stock, diluting the voting power of the common stock, impairing the liquidation rights of the common stock and delaying or preventing a change in control of our common stock without further action by our stockholders and may adversely affect the market price of our common stock. As of December 31, 2020, no shares of our preferred stock were outstanding.

Registration Rights

Certain holders of our Restricted 2024 Notes are entitled to rights with respect to the registration under the Securities Act of the resale of the shares of common stock issuable upon the conversion of the Restricted 2024 Notes held by them, pursuant to which we filed a registration statement on November 4, 2020. Other than with respect to the foregoing, no holders of our securities are entitled to rights with respect to the registration of their securities under the Securities Act.

Anti-Takeover Provisions of Delaware Law

We are subject to Section 203 of the Delaware General Corporation 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 the business combination or the transaction in which the person became an interested stockholder is approved in a prescribed manner. 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, in the case of affiliates or associates of the corporation, within three years prior to the determination of interested stockholder status, owned 15% or more of a corporation’s voting stock. The existence of this provision could have anti-takeover effects with respect to transactions not approved in advance by our board of directors, such as discouraging takeover attempts that might result in a premium over the market price of our common stock. The foregoing provisions of the Delaware General Corporation Law may have the effect of deterring or discouraging hostile takeovers or delaying changes in control of our company.

Charter and Bylaws Anti-Takeover Provisions

Classified Board of Directors

Our certificate of incorporation provides that our board of directors is divided into three classes of directors, with the number of directors in each class to be as nearly equal as possible. Our classified board of directors staggers terms of the three classes and has been implemented through one, two and three-year terms for the initial three classes, followed in each case by full three-year terms. With a classified board of directors, only one-third of the members of our board of directors is elected each year. This classification of directors has the effect of making it more difficult for stockholders to change the composition of our board of directors.

Size of Board of Directors and Removal of Directors

Our certificate of incorporation and bylaws provide that:

• the number of directors will be fixed from time to time exclusively pursuant to a resolution adopted by our board of directors, but must consist of not less than three directors, which will prevent stockholders from circumventing the provisions of our classified board of directors;

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• directors may be removed only for cause; and

• vacancies on our board of directors may be filled only by a majority of directors then in office, even though less than a quorum, or by the sole remaining director, at any meeting of the board of directors.

Authorized Preferred Stock

Our certificate of incorporation provides for the issuance by our board of directors, without stockholder approval, of shares of preferred stock, with voting power, designations, preferences and other special rights as may be determined in the discretion of our board of directors. The issuance of preferred stock could decrease the amount of earnings and assets available for distribution to the holders of common stock or could adversely affect the rights and powers, including voting rights, of holders of common stock. In certain circumstances, such issuance could have the effect of decreasing the market price of the common stock. Preferred stockholders could also make it more difficult for a third party to acquire our company.

No Stockholder Action by Written Consent

Our certificate of incorporation and bylaws require that any action required or permitted to be taken by our stockholders must be effected at a duly called annual or special meeting of stockholders and may not be effected by a consent in writing.

Calling of Special Meetings of Stockholders

Our bylaws provide that special stockholder meetings for any purpose may only be called by a majority of our board of directors, our chairman or our chief executive officer.

Advance Notice Requirements for Stockholder Proposals and Director Nominations

Our bylaws establish an advance notice procedure for stockholder proposals to be brought before an annual meeting of stockholders, including proposed nominations of candidates for election to the board of directors. Stockholders at an annual meeting may only consider proposals or nominations specified in the notice of meeting or brought before the meeting by or at the direction of the board of directors, or by a stockholder of record on the record date for the meeting, who is entitled to vote at the meeting and who has delivered timely written notice in proper form to our secretary of the stockholder’s intention to bring such business before the meeting. These provisions could have the effect of delaying until the next stockholder meeting stockholder actions that are favored by the holders of a majority of our outstanding voting stock. These provisions also could discourage a third party from making a tender offer for our common stock, because even if it acquired a majority of our outstanding voting stock, it would be able to take action as a stockholder, such as electing new directors or approving a merger, only at a duly called stockholders meeting and not by written consent.

Exclusive Forum Charter Provision

Our certificate of incorporation provides that unless we consent in writing to the selection of an alternative forum, the Court of Chancery of the State of Delaware shall be the sole and exclusive forum for (i) any derivative action or proceeding brought on our behalf, (ii) any action asserting a claim of breach of a fiduciary duty owed by any of our directors, officers, employees or agents to us or our stockholders, (iii) any action asserting a claim arising pursuant to any provision of the General Corporation Law of the State of Delaware or our certificate of incorporation or bylaws, or (iv) any action asserting a claim governed by the internal affairs doctrine, in each such case subject to said Court of Chancery having personal jurisdiction over the indispensable parties named as defendants therein. Any person or entity purchasing or otherwise acquiring any interest in shares of our capital stock shall be deemed to have notice of and consented to this provision of our certificate of incorporation.

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Our bylaws provides that unless we consent in writing to the selection of an alternative forum, the federal district courts of the United States of America shall be the sole and exclusive forum for the resolution of any complaint asserting a cause of action arising under the Securities Act. Any person or entity purchasing or otherwise acquiring or holding any interest in any of our securities shall be deemed to have notice of and consented to this provision of our bylaws.

The exclusive forum provision in our certificate of incorporation does not apply to suits brought to enforce any duty or liability created by the Exchange Act or any other claim for which the federal courts have exclusive jurisdiction. We note, however, that federal courts have concurrent jurisdiction over all suits brought to enforce any duty or liability created by the Securities Act. We note that the Supreme Court of the State of Delaware has recently decided that such exclusive forum provisions for causes of action arising under the Securities Act would be enforced under Delaware law and that investors cannot waive compliance with the federal securities laws and the rules and regulations thereunder. Although we believe this provision benefits us by providing increased consistency in the application of Delaware law in the types of lawsuits to which it applies, this provision may have the effect of discouraging lawsuits against our directors and officers.

Indemnification of Directors and Officers

Our certificate of incorporation and bylaws provide that we will, to the fullest extent permitted by Delaware corporate law, subject to certain limitations, indemnify any person made or threatened to be made a party to a proceeding by reason of that person’s former or present official capacity with us against judgments, penalties, fines, settlements and reasonable expenses. Any such person is also entitled, subject to certain limitations, to payment or reimbursement of reasonable expenses (including attorneys’ fees and disbursements and court costs) in advance of the final disposition of the proceeding.

The provision regarding indemnification of our directors and officers in our certificate of incorporation will generally not limit liability under state or federal securities laws.

We maintain a directors’ and officers’ insurance policy pursuant to which our directors and officers are insured against liability for actions taken in their capacities as directors and officers. We believe that these indemnification provisions and insurance are useful to attract and retain qualified directors and officers.

In addition, we have entered into indemnification agreements with each of our directors and named executive officers, which also provide, subject to certain exceptions, for indemnification for related expenses, including, among others, reasonable attorney’s fees, judgments, fines and settlements incurred in any action or proceeding. Your investment may be adversely affected to the extent that, in a class action or direct suit, we pay the costs of settlement and damage awards against directors and officers pursuant to these indemnification provisions.

Insofar as the foregoing provisions permit indemnification of directors, officers or persons controlling us for liability arising under the Securities Act, we have been informed that in the opinion of the SEC, this indemnification is against public policy as expressed in the Securities Act and is therefore unenforceable.

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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. The terms of any warrants offered under an applicable prospectus supplement may differ from the terms described below as set forth therein. 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 in one or more series. We may issue warrants independently or together with common stock and/or preferred stock, and the warrants may be attached to or separate from these securities.

We will evidence each series of warrants by warrant certificates that we will issue under a separate warrant agreement. We will enter into the warrant agreement with a warrant agent. We will indicate the name and address of the 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;

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

• 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 periods during which, and places at which, the warrants are exercisable;

• the manner of exercise;

• the dates on which the right to exercise the warrants will commence and expire;

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

• federal income tax consequences of holding or exercising the warrants;

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

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

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DESCRIPTION OF DEBT SECURITIES

The debt securities will be direct obligations of the Company and will be either senior or subordinated debt securities and may be either secured or unsecured. We will issue the debt securities under the Indenture, dated as of April 19, 2018 (the “Base Indenture”), between the Company and The Bank of New York Mellon Trust Company, N.A., as trustee (the “Trustee”). While the terms we have summarized below will apply generally to any debt securities that we may offer under this prospectus, 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 offered under a prospectus supplement may differ from the terms described below. Unless the context requires otherwise, whenever we refer to the indenture, we also are referring to any supplemental indentures that specify the terms of a particular series of debt securities. For purposes of this description of debt securities, references to “the Company,” “we,” “our” and “us” refer only to Clovis Oncology, Inc. and not to its subsidiaries.

General

We may issue debt securities in one or more series. A supplemental indenture will set forth specific terms of each series of debt securities. There will be prospectus supplements relating to particular series of debt securities. Each prospectus supplement will describe with respect to the particular series of debt securities offered:

• the title of the debt securities;

• any limit upon the aggregate principal amount of debt securities which we may issue;

• the date or dates on which the debt securities will mature and the amount of principal which will be payable when the debt securities mature;

• the rate or rates (which may be fixed or variable) at which the debt securities will bear interest, if any, or contingent interest, if any, as well as the dates from which interest will accrue, the dates on which interest will be payable, and the record date for the interest payable on any payment date;

• the currency or currencies in which principal, premium, if any, and interest, if any, will be paid;

• the place or places where principal, premium, if any, and interest, if any, on the debt securities will be payable;

• any provisions regarding our right to repurchase or redeem debt securities or of holders to require us to repurchase or redeem debt securities;

• whether the debt securities are senior or subordinated debt securities, and if subordinated debt securities, the terms of such subordination;

• the right, if any, of holders of the debt securities to convert them into common stock or other securities, including any contingent conversion provisions and any provisions intended to prevent dilution of those conversion rights;

• any provisions requiring or permitting us to make payments to a sinking fund which will be used to redeem debt securities or a purchase fund which will be used to purchase debt securities;

• any index or formula used to determine the required payments of principal, premium, if any, or interest, if any;

• the percentage of the principal amount of the debt securities which is payable if maturity of the debt securities is accelerated because of a default;

• any special or modified events of default or covenants with respect to the debt securities; and

• any other terms of the debt securities, which may be different from the terms set forth in this prospectus.

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The Base Indenture does not contain any restrictions on the payment of dividends or the repurchase of our securities or any financial covenants. However, supplemental indentures relating to particular series of debt securities, or other indentures or agreements to which we are a party, may contain provisions of that type.

We may issue debt securities at a discount from, or at a premium to, their stated principal amount. A prospectus supplement may describe federal income tax considerations and other special considerations applicable to a debt security issued with original issue discount or a premium.

If the principal of, premium, if any, or interest, if any, with regard to any series of debt securities is payable in a foreign currency, then in the prospectus supplement relating to those debt securities, we will describe any restrictions on currency conversions, tax considerations or other material restrictions with respect to that issue of debt securities.

Form of Debt Securities

We may issue debt securities in certificated or uncertificated form, in registered form with or without coupons or in bearer form with coupons, if applicable.

We may issue debt securities of a series in the form of one or more global certificates evidencing all or a portion of the aggregate principal amount of the debt securities of that series. We may deposit the global certificates with depositaries, and the global certificates may be subject to restrictions upon transfer or upon exchange for debt securities in individually certificated form.

Events of Default and Remedies

An event of default with respect to each series of debt securities will include:

• our default in payment of the principal of or premium, if any, on any debt securities when it becomes due and payable at its stated maturity or upon redemption, acceleration or otherwise, of any series beyond any applicable grace period specified in a supplemental indenture;

• our default for 30 days or a different period specified in a supplemental indenture, which may be no period, in payment of any installment of interest due with regard to debt securities of any series;

• our default for 90 days after notice in the observance or performance of any other covenants or agreements with regard to any debt securities of a series or the indenture; and

• certain events involving our bankruptcy, insolvency or reorganization.

The Trustee may withhold notice to the holders of any series of debt securities of any default (except a default in payment of principal, premium, if any, or interest, if any) if the Trustee considers it in the interest of the holders of the series to do so.

The Trustee will give to the holders of any debt securities of a series notice of any default with regard to such debt securities of that series known to the Trustee (upon receipt in writing by a trust officer), within 90 days after it occurs; provided, that, except in the case of a default in the payment of the principal of, or premium, if any, or interest on any debt security, the Trustee will be protected in withholding notice of the default if and so long as a committee of its trust officers in good faith determines it in the interest of the holders of the series to do so.

If any event of default occurs and is continuing, the Trustee, by notice to us, or the holders of not less than 25% in aggregate principal amount of the series of debt securities then outstanding, by notice to us and the Trustee, may declare the principal of and accrued interest, if any, on all the debt securities of that series to be due and payable immediately. However, if we cure all events of default (except the failure to pay principal, premium

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or interest which became due solely because of the acceleration) and certain other conditions are met, that declaration may be rescinded and past defaults may be waived by the holders of a majority in aggregate principal amount of the series of debt securities then outstanding.

The holders of a majority of the outstanding principal amount of a series of debt securities will have the right to direct the time, method and place of conducting proceedings for any remedy available to the Trustee, subject to certain limitations specified in the indenture.

A prospectus supplement will describe any additional or different events of default and remedies which apply to any series of debt securities.

Modification of the Indenture or Other Indentures

Unless otherwise indicated in an applicable prospectus supplement (and related supplemental indenture relating to a particular series of debt securities):

• We and the Trustee may, without the consent of holders of debt securities, modify the indenture to (i) cure errors, omissions, defects, inconsistencies or ambiguities, (ii) comply with covenants in the indenture described below under the heading “Mergers and Other Transactions,” (iii) establish the form and terms of any debt securities of any series as contemplated in the indenture, (iv) provide for uncertificated debt securities in addition to or in place of certificated debt securities or (v) amend, modify or supplement the Base Indenture, or any supplemental indenture, to make any change that does not materially adversely affect the rights of any holder of debt securities, provided that any amendment, modification or supplement that conforms the Base Indenture or any supplemental indenture, as applied to any series of debt securities, to the terms described in the prospectus (including any prospectus supplement) pursuant to which such debt securities were initially sold shall be deemed not to adversely affect the rights of holders.

• We and the Trustee may also (i) amend or supplement the indenture or the debt securities without notice to any holder but with the written consent of the holders of a majority in aggregate principal amount of the debt securities of all series then outstanding or (ii) supplement the Base Indenture with regard to a series of debt securities, amend or supplement a supplemental indenture relating to a series of debt securities, or amend the debt securities of a series, without notice to any holder but with the written consent of the holders of a majority in aggregate principal amount of the debt securities of that series then outstanding. The holders of a majority in principal amount of the debt securities of all series then outstanding may waive compliance by us with any provision of the indenture or the debt securities without notice to any holder. The holders of a majority in principal amount of the debt securities of any series then outstanding may waive compliance with any provision of the Base Indenture, any supplemental indenture or the debt securities of that series with regard to the debt securities of that series without notice to any holder. However, without the consent of the holder so affected, no amendment, supplement or waiver, including a waiver of existing events of default, may: extend the fixed maturity of any debt securities, reduce the rate or extend the time for payment of interest, if any, on any debt securities, reduce the principal amount of any debt securities or the premium, if any, on any debt securities, impair or affect the right of a holder to institute suit for the payment of principal, premium, if any, or interest, if any, with regard to any debt securities, change the currency in which any debt securities are payable or impair the right, if any, to convert any debt securities into common stock or any other of our securities, reduce the percentage of debt securities required to consent to an amendment, supplement or waiver, reduce the amount payable upon the redemption of any debt security or change the time at which any debt security may or will be redeemed, modify the provisions of any supplemental indenture with respect to subordination of any debt securities of a series in a manner adverse to the holders or make any change to certain provisions of the indenture relating to, among other things, the right of holders of debt securities to receive payment of the principal of, premium and interest on those debt securities, to demand conversion and to waive existing events of default.

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Mergers and Other Transactions

Unless otherwise indicated in an applicable prospectus supplement (and related supplemental indenture relating to a particular series of debt securities), we may not consolidate with or merge into any other entity, or convey, transfer or lease our properties and assets substantially as an entirety to another person, unless (1) the entity formed by the consolidation or into which we are merged, or which acquires or leases our properties and assets substantially as an entirety, is a corporation organized and existing under the laws of the United States of America, a State of the United States of America or the District of Columbia, and assumes by a supplemental indenture all our obligations with regard to outstanding debt securities and our other covenants under the indenture, (2) with regard to each series of debt securities, immediately after giving effect to the transaction, no event of default with respect to that series of debt securities, and no event which would become an event of default, will have occurred and be continuing and (3) we have delivered to the Trustee an officers’ certificate and an opinion of counsel, stating that the consolidation, merger, conveyance, transfer or lease and the supplemental indenture (or the supplemental indentures together) comply with the applicable section of the indenture and that all the conditions precedent relating to the transaction set forth in the applicable section of the indenture have been fulfilled.

Upon any event described in the immediately preceding paragraph, the successor entity will succeed to and be substituted for us, and may exercise every right of ours under the Base Indenture and each supplemental indenture relating to outstanding series of debt securities, and the predecessor entity will be relieved of all obligations and covenants under the Base Indenture and each supplemental indenture.

Concerning the Trustee

The Bank of New York Mellon Trust Company, N.A. is the Trustee for each series of debt securities. You should note that if the Trustee becomes a creditor of ours, the indenture and the Trust Indenture Act of 1939 limit the rights of the Trustee to obtain payment of claims in certain cases, or to realize on certain property received in respect of certain claims, as security or otherwise. The Trustee and its affiliates may engage in, and will be permitted to continue to engage in, other transactions with us and our affiliates. If, however, the Trustee, acquires any “conflicting interest” within the meaning of the Trust Indenture Act of 1939, it must eliminate the conflict or resign.

The holders of a majority in principal amount of the then outstanding debt securities of any series may direct the time, method and place of conducting any proceeding for any remedy available to the Trustee with regard to that series or of exercising any trust or power conferred on the Trustee with regard to the debt securities of that series. However, the Trustee may refuse to follow any direction that conflicts with law or the indenture or, subject to the indenture, that the Trustee determines is unduly prejudicial to the rights of other holders or that would involve the Trustee in personal liability; provided, however, that the Trustee may take any other action deemed proper by the Trustee that is not inconsistent with such direction. Prior to taking any action as a result of a direction given under this paragraph, the Trustee will be entitled to indemnification satisfactory to it in its sole discretion against all losses and expenses caused by taking or not taking that action. If an event of default occurs and is continuing, the Trustee, in the exercise of its rights and powers, must use the degree of care and skill in their exercise, as a prudent person would exercise in the conduct of his or her own affairs, provided that, the Trustee will be under no obligation to exercise any of its rights or powers under the indenture at the request of any of the holders of the debt securities, unless they have offered to the Trustee indemnity or security satisfactory to the Trustee.

Governing Law

Each of the Base Indenture, each supplemental indenture, and the debt securities issued under them will be governed by, and construed in accordance with, the laws of the State of New York.

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PLAN OF DISTRIBUTION

We may sell our securities from time to time pursuant to underwritten public offerings, negotiated transactions, block trades or a combination of these methods. We may sell our securities separately or together:

• to or through one or more underwriters, brokers or dealers;

• through agents;

• directly to one or more purchasers; or

• through a combination of any of these methods of sale.

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

• at a fixed price or prices, which may be changed;

• at market prices prevailing at the time of sale;

• at prices related to such prevailing market prices; or

• at negotiated prices.

The related prospectus supplement will set forth the terms of each offering, including:

• the name or names of any agents, dealers, underwriters or investors who purchase the securities;

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

• the amount of any compensation, discounts, commissions or fees to be received by the underwriters, dealer or agents;

• any over-allotment options under which underwriters may purchase additional securities from us;

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

• any securities exchanges on which such securities may be listed;

• the terms of any indemnification provisions, including indemnification from liabilities under the federal securities laws; and

• the nature of any transaction by an underwriter, dealer or agent during the offering that is intended to stabilize or maintain the market prices of the securities.

Direct Sales and Sales Through Agents

We may solicit directly offers to purchase securities being offered by this prospectus. We may also designate agents to solicit offers to purchase our securities from time to time. We may sell our securities offered by this prospectus by any method permitted by law, including sales deemed to be an “at the market” offering as defined in Rule 415(a)(4) under the Securities Act, including without limitation sales made directly on The Nasdaq Global Select Market, on any other existing trading market for our securities or to or through a market maker. We will name in a prospectus supplement any agent involved in the offer or sale of our securities.

Sales Through Underwriters or Dealers

If we utilize a dealer in the sale of our securities being offered by this prospectus, we will sell our securities to the dealer, as principal. The dealer may then resell our securities to the public at varying prices to be determined by the dealer at the time of resale.

If we utilize an underwriter in the sale of our securities being offered by this prospectus, we will execute an underwriting agreement with the underwriter at the time of sale and we will provide the name of any underwriter

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in the prospectus supplement that the underwriter will use to make resales of our securities to the public. In connection with the sale of our securities, we or the purchasers of our securities for whom the underwriter may act as agent may compensate the underwriter in the form of underwriting discounts or commissions. The underwriter may sell our securities to or through dealers, and the underwriter may compensate those dealers in the form of discounts, concessions or commissions.

We will provide in the applicable prospectus supplement any compensation we will pay to underwriters, dealers or agents in connection with the offering of our securities, and any discounts, concessions or commissions allowed by underwriters to participating dealers. 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 securities pursuant to this prospectus and any applicable prospectus supplement. Underwriters, dealers and agents participating in the distribution of our securities may be deemed to be underwriters within the meaning of the Securities Act, and any discounts and commissions received by them and any profit realized by them on resale of our securities may be deemed to be underwriting discounts and commissions. In the event that an offering made pursuant to this prospectus is subject to FINRA Rule 5121, the prospectus supplement will comply with the prominent disclosure provisions of that rule.

To facilitate the offering of our securities, certain persons participating in the offering may engage in transactions that stabilize, maintain or otherwise affect the price of our securities. This may include over-allotments or short sales of our securities, which involves the sale by persons participating in the offering of more securities than we sold to them. In these circumstances, these persons would cover such over-allotments or short positions by making purchases in the open market or by exercising their over-allotment option. In addition, these persons may stabilize or maintain the price of our securities by bidding for or purchasing our securities in the open market or by imposing penalty bids, whereby selling concessions allowed to dealers participating in the offering may be reclaimed if the 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 our securities at a level above that which might otherwise prevail in the open market. These transactions may be discontinued at any time.

Delayed Delivery Contracts

We may authorize underwriters, dealers or agents to solicit offers by certain purchasers to purchase our 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. The contracts will be subject only to those conditions set forth in the prospectus supplement, and the prospectus supplement will set forth any commissions we pay for solicitation of these contracts.

Derivative Transactions

We may enter into derivative transactions with third parties, or sell our securities not covered by this prospectus to third parties in privately negotiated transactions. If the applicable prospectus supplement so indicates, in connection with any derivative transaction, the third parties may sell our securities covered by this prospectus and the applicable prospectus supplement, including in short sale transactions. If so, the third party may use our securities pledged by us or borrowed from us or others to settle those sales or to close out any related open borrowings of securities, and may use our securities received from us in settlement of those derivatives to close out any related open borrowings of securities. The third party in such sale transactions will be an underwriter and will be identified in the applicable prospectus supplement or a post-effective amendment to the registration statement of which this prospectus is a part. In addition, we may otherwise loan or pledge our securities to a financial institution or other third party that in turn may sell our securities short using this prospectus. Such financial institution or other third party may transfer its economic short position to investors in our securities or in connection with a concurrent offering of other securities.

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General Information

Any securities offered other than common stock will be a new issue and, other than the common stock, which is listed on The Nasdaq Global Select Market, will have no established trading market. We may elect to list any series of securities on an exchange, and in the case of the common stock, on any additional exchange, but, unless otherwise specified in the applicable prospectus supplement and/or other offering material, we shall not be obligated to do so. No assurance can be given as to the liquidity of the trading market for any of the securities.

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

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LEGAL MATTERS

Willkie Farr & Gallagher LLP, New York, New York will pass upon the validity of any securities we offer by this prospectus. If the validity of any securities is also passed upon by counsel for the underwriters of an offering of those securities, that counsel will be named in the prospectus supplement relating to that offering.

EXPERTS

The consolidated financial statements of Clovis Oncology, Inc. appearing in Clovis Oncology, Inc.’s Annual Report (Form 10-K) for the year ended December 31, 2020, and the effectiveness of Clovis Oncology, Inc.’s internal control over financial reporting as of December 31, 2020, have been audited by Ernst & Young LLP, independent registered public accounting firm, as set forth in their reports thereon, included therein, and incorporated herein by reference. Such financial statements are, and audited financial statements to be included in subsequently filed documents will be, incorporated herein in reliance upon the reports of Ernst & Young LLP pertaining to such financial statements and the effectiveness of our internal control over financial reporting as of the respective dates (to the extent covered by consents filed with the SEC) given on the authority of such firm as experts in accounting and auditing.

WHERE YOU CAN FIND MORE INFORMATION

We file reports and proxy statements with the SEC. These filings include our Annual Report on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and proxy statements on Schedule 14A, as well as any amendments to those reports and proxy statements, are available free of charge through our website as soon as reasonably practicable after we file them with, or furnish them to, the SEC. Once at www.clovisoncology.com, go to Investors & News/SEC Filings to locate copies of such reports and proxy statements. Our website and the information contained on, or that can be accessed through, the website will not be deemed to be incorporated by reference in, and are not considered part of, this prospectus. You should not rely on any such information in making your decision whether to purchase our securities. The SEC also maintains a website at www.sec.gov that contains reports, proxy and information statements and other information regarding us and other issuers that file electronically with the SEC.

We have filed with the SEC a registration statement on Form S-3 under the Securities Act of 1933, as amended, relating to the securities being offered by this prospectus. This prospectus, which constitutes part of that registration statement, does not contain all of the information set forth in the registration statement or the exhibits and schedules which are part of the registration statement. For further information about us and the securities offered, see the registration statement and the exhibits and schedules thereto. Statements contained in this prospectus regarding the contents of any contract or any other document to which reference is made are not necessarily complete, and, in each instance where a copy of a contract or other document has been filed as an exhibit to the registration statement, reference is made to the copy so filed, each of those statements being qualified in all respects by the reference.

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INCORPORATION BY REFERENCE

The SEC allows us to “incorporate by reference” into this prospectus the information we file with the SEC in other documents, which means that we can disclose important information to you by referring you to those documents instead of having to repeat the information in this prospectus. The information incorporated by reference is considered to be part of this prospectus, and later information that we file with the SEC will automatically update and supersede such information. We incorporate by reference the documents listed below and any future information filed (rather than furnished) with the SEC under Sections 13(a), 13(c), 14 or 15(d) of the Exchange Act between the date of this prospectus and the date all securities to which this prospectus relates have been sold or the offering is otherwise terminated and also between the date of the initial registration statement and prior to effectiveness of the registration statement, provided, however, that we are not incorporating any information furnished under Item 2.02 or Item 7.01 of any Current Report on Form 8-K:

• our Annual Report on Form 10-K for the year ended December 31, 2020, as filed with the SEC on February 25, 2021;

• the information included in our Definitive Proxy Statement on Schedule 14A, as filed with the SEC on April 24, 2020, to the extent incorporated by reference in Part III of our Annual Report on Form 10-K for the year ended December 31, 2019;

• our Current Report on Form 8-K, as filed with the SEC on January 11, 2021 (only with respect to the Item 8.01 information); and

• the description of our common stock contained in our registration statement on Form 8-A, as filed with the SEC on November 10, 2011, as updated by Exhibit 4.6 to our Annual Report on Form 10-K for the year ended December 31, 2020, including any amendments or reports filed for the purpose of updating the description.

We will furnish without charge to you a copy of any or all of the documents incorporated by reference, including exhibits to these documents, upon written or oral request. Direct your written request to: Investor Relations, Clovis Oncology, Inc., 5500 Flatiron Parkway, Suite 100, Boulder, Colorado 80301, or contact Investor Relations at (303) 625-5000.

A statement contained in a document incorporated by reference into this prospectus shall be deemed to be modified or superseded for purposes of this prospectus to the extent that a statement contained in this prospectus, any prospectus supplement or in any other subsequently filed document which is also incorporated in this prospectus modifies or replaces such statement. Any statements so modified or superseded shall not be deemed, except as so modified or superseded, to constitute a part of this prospectus.

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Up to $125,000,000

Common Stock

PROSPECTUS SUPPLEMENT

August 16, 2021