UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 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: 001-39980 Sensei Biotherapeutics, Inc. (Exact name of Registrant as specified in its Charter) Delaware 83-1863385 (State or other ju ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q (Mark One) ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2023 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: 001-39980 Sensei Biotherapeutics, Inc. (Exact name of Registrant as specified in its Charter) Delaware 83-1863385 (State or other j ...

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 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: 001-39980 Sensei Biotherapeutics, Inc. (Exact name of Registrant as specified in its Charter) Delaware 83-1863385 (State or other jurisd ...

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| --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | --- | |-------|-------|-------|-------|-------|-------|-------|-------|-------|---------------------------------------------|-------|--------------|-------|-------|-------| | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | | Next Generation Immuno-Oncology Medicines | | | | | | | | | | | | | | | | John K. Celebi, MBA | | | | | | | | | | | | | | | | President & Chief Executive Officer | | | | ...