SMMT Summit Therapeutics Inc

UNITED STATES

SECURITIES AND EXCHANGE COMMISSION

Washington, D.C. 20549

FORM 6-K

REPORT OF FOREIGN PRIVATE ISSUER

PURSUANT TO RULE 13a-16 OR 15d-16

UNDER THE SECURITIES EXCHANGE ACT OF 1934

For the month of February 2020.

Commission File Number 001-36866

SUMMIT THERAPEUTICS PLC

(Translation of registrant’s name into English)

136a Eastern Avenue

Milton Park, Abingdon

Oxfordshire OX14 4SB

United Kingdom

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F  ☒            Form 40-F  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(1):  ☐

Indicate by check mark if the registrant is submitting the Form 6-K in paper as permitted by Regulation S-T Rule 101(b)(7):  ☐

On February 26, 2020, Summit Therapeutics plc (the “Company”) announced that it appointed Robert W. Duggan as Executive Chairman of the Board of Directors of the Company (the “Board”) with immediate effect. Glyn Edwards will continue as Executive Director and Chief Executive Officer of the Company.

This Report on Form 6-K, including Exhibit 99.1, is hereby incorporated by reference into the Company’s Registration Statement on Form F-3 (File No. 333-232074).