Exhibit 5.1

		787 Seventh Avenue
		New York, NY 10019-6099
		Tel: 212 728 8000
		Fax: 212 728 8111

May 17, 2021

Clovis Oncology, Inc.

5500 Flatiron Parkway, Suite 100

Boulder, Colorado 80301

Re: Registration Statements on Form S-3

Ladies and Gentlemen:

We have acted as counsel to Clovis Oncology, Inc., a corporation organized under the laws of the State of Delaware (the “Company”), in connection with the Company’s offer and sale of shares of common stock, par value $0.001 per share, of the Company (the “Common Stock”), having an aggregate offering price of up to $75,000,000 (the “Shares”) to be issued pursuant to that certain Distribution Agreement, dated May 17, 2021, by and among the Company, J. P. Morgan Securities LLC and BofA Securities, Inc. (the “Distribution Agreement”), The Shares are being offered pursuant to the Company’s registration statement on Form S-3 filed with the U.S. Securities and Exchange Commission (the “Commission”) under the Securities Act of 1933, as amended (the “Securities Act”) on February 25, 2021 (File No. 333-253485) as amended by pre-effective Amendment No. 1 thereto filed with the Commission on May 5, 2021 (as so amended and filed, the “Registration Statement”) and the related prospectus contained in the Registration Statement, as supplemented by the prospectus supplement, dated May 17, 2021 and filed with the Commission pursuant to Rule 424(b) under the Securities Act (as so supplemented, the “Prospectus”). This opinion is being furnished in connection with the requirements of Item 601(b)(5) of Regulation S-K under the Securities Act, and no opinion is expressed herein as to any other matter pertaining to the contents of the Registration Statement or the Prospectus, other than as expressly stated herein with respect to the issuance of the Shares.

We have examined copies of the Amended and Restated Certificate of Incorporation of the Company, as amended, the Amended and Restated Bylaws of the Company, as amended, the Registration Statements, the Prospectus, the Distribution Agreement, all relevant resolutions adopted by the Company’s Board of Directors and committees thereof, and other records, certificates and documents that we have deemed necessary for the purpose of this opinion. We have also examined and are familiar with originals or copies, certified or otherwise identified to our satisfaction, of such other documents, corporate records, papers, statutes and authorities as we have deemed necessary to form a basis for the opinion hereinafter expressed.

As to questions of fact material to the opinion expressed below, we have relied without independent check or verification upon certificates and comparable documents of public officials and officers and representatives of the Company and statements of fact contained in the documents

NEW YORK WASHINGTON HOUSTON PALO ALTO SAN FRANCISCO CHICAGO PARIS LONDON FRANKFURT BRUSSELS MILAN ROME

Clovis Oncology, Inc.

May 17, 2021

Page 2

we have examined. In our examination and in rendering our opinion contained herein, we have assumed (i) the genuineness of all signatures of all parties; (ii) the authenticity of all corporate records, documents, agreements, instruments and certificates submitted to us as originals and the conformity to original documents and agreements of all documents and agreements submitted to us as conformed, certified or photostatic copies; and (iii) the capacity of natural persons.

Based on the foregoing, and subject to the qualifications and assumptions set forth herein, we are of the opinion that the Shares have been duly authorized by all necessary corporate action on the part of the Company and, when issued, sold and paid for (at not less than par value) in accordance with the terms set forth in the Prospectus and the Distribution Agreement and duly registered on the books of the transfer agent and registrar therefor in the name or on behalf of the purchasers, will be validly issued, fully paid and non-assessable. In rendering the foregoing opinion, we have assumed that upon the issue of any of the Shares, the total number of shares of Common Stock issued and outstanding will not exceed the total number of shares of Common Stock that the Company is then authorized to issue under its Amended and Restated Certificate of Incorporation, as amended.

This opinion is limited to the General Corporation Law of the State of Delaware and to the specific legal matters expressly addressed herein, and no opinion is expressed or implied with respect to the laws of any other jurisdiction or any legal matter not expressly addressed herein.

The opinions expressed herein are given as of the date hereof, and we assume no obligation to update or supplement such opinions after the date hereof.

We hereby consent to the filing of this opinion as an exhibit to the Company’s Current Report on Form 8-K, which is incorporated by reference into the Registration Statement, and to the reference to our firm under the caption “Legal Matters” in the Prospectus. In giving such consent, we do not thereby admit that we are in the category of persons whose consent is required under Section 7 of the Securities Act or the rules and regulations of the Commission.