UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2019 Commission File Number: 001-38796 GOSSAMER BIO, INC. (Exact name of Registrant as specified in its charter) OR Delaware 47-5461709 (State or other jurisdiction of incorporation or organization) 3013 Science Park Road San Diego, California 92121 (Address of principal executive offices) (Zip Cod ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 10-K ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2018 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number; 001-38796 GOSSAMER BIO, INC. (Exact name of Registrant as specified in its charter) Delaware 47-5461709 (State or other jurisdiction of incorporation or organization) 3013 Science P ...