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UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington , D.C. 20549 FORM 8 - K CURRENT REPORT Pursuant to Section 13 or 15 ( d ) of The Securities Exchange Act of 1934 Date of Report ( Date of Earliest Event Reported ) : November 15 , 2021 Summit Therapeutics Inc. ( Exact Name of Registrant as Specified in Its Charter ) Delaware ( State or Other Jurisdiction of Incorporation ) One Broadway , 14th Floor , Cambridge , MA 001-36866 ( Commission File Number ) ( Address of Principal Executive Offices ) 37-1979717 ( IRS Employer Identification No. ) 02142 ( Zip Code ) Registrant's Telephone Number , Including Area Code : 617-514-7149 Not Applicable ( Former Name or Former Address , If Changed Since Last Report ) Check the appropriate box below if the Form 8 - K filing is intended to simultaneously satisfy the filing obligation of the registrant under any of the following provisions ( see General Instruction A.2 . below ) : Written communications pursuant to Rule 425 under the Securities Act ( 17 CFR 230.425 ) ☐ Soliciting material pursuant to Rule 14a - 12 under the Exchange Act ( 17 CFR 240.14a - 12 ) Pre - commencement communications pursuant to Rule 14d - 2 ( b ) under the Exchange Act ( 17 CFR 240.14d - 2 ( b ) ) ☐ Pre - commencement communications pursuant to Rule 13e - 4 ( c ) under the Exchange Act ( 17 CFR 240.13e - 4 ( c ) ) Securities registered pursuant to Section 12 ( b ) of the Act :