UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 FORM 10-Q (Mark One) For the quarterly period ended September 30, 2021 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to . Commission File Number: 001-38096 G1 THERAPEUTICS, INC. (Exact Name of Registrant as Specified in its Charter) Delaware 26-3648180 ( State or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification No.) 700 Park ...