TCRR / Tcr2 Therapeutics Inc - Pengajuan SECLaporan Tahunan, Pernyataan Proksi

TCRR / Tcr2 Therapeutics Inc / TANG CAPITAL PARTNERS LP - AMENDMENT NO. 3 Passive Investment

SC 13G/A 1 p26241sc13ga3.htm AMENDMENT NO. 3 Securities and Exchange Commission Washington, DC 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 3)* TCR2 Therapeutics Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of This Statement) Check the a

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 15 CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 15 CERTIFICATION AND NOTICE OF TERMINATION OF REGISTRATION UNDER SECTION 12(g) OF THE SECURITIES EXCHANGE ACT OF 1934 OR SUSPENSION OF DUTY TO FILE REPORTS UNDER SECTIONS 13 AND 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934. Commission File No. 001-38811 TCR2 Therapeutics Inc. (Exact name of registrant as specified in its

As filed with the Securities and Exchange Commission on June 1, 2023.

As filed with the Securities and Exchange Commission on June 1, 2023. Registration No. 333-229691 Registration No. 333-237481 Registration No. 333-254354 Registration No. 333-263770 Registration No. 333-270766 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO Form S-8 Registration No. 333-229691 Form S-8 Registration No. 333-237481 Form S-8 R

SECOND Amended and Restated BY-LAWS OF TCR2 THERAPEUTICS INC. ARTICLE I OFFICES

Exhibit 3.2 SECOND Amended and Restated BY-LAWS OF TCR2 THERAPEUTICS INC. ARTICLE I OFFICES SECTION 1.1. REGISTERED OFFICE. The registered office of the corporation shall be established and maintained at the office of The Corporation Trust Company, 1209 Orange Street, Corporation Trust Center, Wilmington, Delaware 19801, and said corporation shall be the registered agent of this corporation in cha

As filed with the Securities and Exchange Commission on June 1, 2023.

As filed with the Securities and Exchange Commission on June 1, 2023. Registration No. 333-229691 Registration No. 333-237481 Registration No. 333-254354 Registration No. 333-263770 Registration No. 333-270766 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO Form S-8 Registration No. 333-229691 Form S-8 Registration No. 333-237481 Form S-8 R

As filed with the Securities and Exchange Commission on June 1, 2023.

As filed with the Securities and Exchange Commission on June 1, 2023. Registration No. 333-229691 Registration No. 333-237481 Registration No. 333-254354 Registration No. 333-263770 Registration No. 333-270766 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO Form S-8 Registration No. 333-229691 Form S-8 Registration No. 333-237481 Form S-8 R

As filed with the Securities and Exchange Commission on June 1, 2023.

As filed with the Securities and Exchange Commission on June 1, 2023. Registration No. 333-229691 Registration No. 333-237481 Registration No. 333-254354 Registration No. 333-263770 Registration No. 333-270766 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO Form S-8 Registration No. 333-229691 Form S-8 Registration No. 333-237481 Form S-8 R

As filed with the Securities and Exchange Commission on June 1, 2023.

As filed with the Securities and Exchange Commission on June 1, 2023. Registration No. 333-236965 Registration No. 333-252244 Registration No. 333-254355 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT NO. 333-236965 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT NO. 333-252244 POST-EFFECTI

As filed with the Securities and Exchange Commission on June 1, 2023.

As filed with the Securities and Exchange Commission on June 1, 2023. Registration No. 333-236965 Registration No. 333-252244 Registration No. 333-254355 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT NO. 333-236965 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT NO. 333-252244 POST-EFFECTI

As filed with the Securities and Exchange Commission on June 1, 2023.

As filed with the Securities and Exchange Commission on June 1, 2023. Registration No. 333-229691 Registration No. 333-237481 Registration No. 333-254354 Registration No. 333-263770 Registration No. 333-270766 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO Form S-8 Registration No. 333-229691 Form S-8 Registration No. 333-237481 Form S-8 R

Changes in Control of Registrant, Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Material Modification to Rights of Security Holders, Notice of Delisting or Failure to Satisfy a Continued Listing Rule or Standard; Transfer of Listing, Financial Statements and Exhibits, Completion of Acquisition or Disposition of Assets

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): June 1, 2023 TCR2 Therapeutics Inc. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

FOURTH amended and restated CERTIFICATE OF INCORPORATION TCR2 Therapeutics Inc.

Exhibit 3.1 FOURTH amended and restated CERTIFICATE OF INCORPORATION OF TCR2 Therapeutics Inc. 1. Name. The name of the corporation shall be TCR2 Therapeutics Inc. (the "Corporation"). 2. Registered Office. The address of its registered office in the State of Delaware is: The Corporation Trust Company, 1209 Orange Street, Corporation Trust Center, Wilmington, New Castle County, Delaware 19801. The

As filed with the Securities and Exchange Commission on June 1, 2023.

As filed with the Securities and Exchange Commission on June 1, 2023. Registration No. 333-236965 Registration No. 333-252244 Registration No. 333-254355 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT NO. 333-236965 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-3 REGISTRATION STATEMENT NO. 333-252244 POST-EFFECTI

Filed by Adaptimmune Therapeutics plc

Filed by Adaptimmune Therapeutics plc pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: TCR2 Therapeutics Inc.

Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

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): May 30, 2023 TCR2 Therapeutics Inc. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

Entry into a Material Definitive Agreement, Financial Statements and Exhibits

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): May 24, 2023 (May 23, 2023) TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation)

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): May 24, 2023 (May 23, 2023) TCR2

425 1 d511078d425.htm 425 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): May 24, 2023 (May 23, 2023) TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other juris

LEASE MODIFICATION AGREEMENT

EX-10.2 Exhibit 10.2 LEASE MODIFICATION AGREEMENT THIS LEASE MODIFICATION AGREEMENT (“this Agreement”) is dated as of May 23, 2023 by and between ARE-MARYLAND NO. 31, LLC, a Maryland limited liability company (“Landlord”), and TCR2 THERAPEUTICS INC., a Delaware corporation (“TCR2”). RECITALS A. Landlord and TCR2 are parties to that certain Lease Agreement dated as of March 23, 2021 (“Lease”), wher

ASSIGNMENT OF LEASE

EX-10.1 Exhibit 10.1 ASSIGNMENT OF LEASE THIS ASSIGNMENT OF LEASE (this “Assignment”) is made as of May 23, 2023 but effective as of June 1, 2023 (“Effective Date”) is made by and between TCR2 THERAPEUTICS INC., a Delaware corporation (“TCR2”), and ASTRAZENECA PHARMACEUTICALS LP, a Delaware limited partnership (“AstraZeneca”). EXPLANATORY STATEMENT A. ARE-Maryland No. 31, LLC, a Maryland limited l

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2))

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): May 22, 2023 TCR2 Therapeutics In

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): May 22, 2023 TCR2 Therapeutics Inc. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

Other Events

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): May 22, 2023 TCR2 Therapeutics Inc. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant x Filed by a Party other than the Registrant ¨ Check the appropriate box: ¨ Preliminary Proxy Statement ¨ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ¨ Defin

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): May 11, 2023 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

and $ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 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 001-38811 TCR2 Therapeutics Inc.

TCR2 Therapeutics Reports First Quarter 2023 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports First Quarter 2023 Financial Results and Provides Corporate Update CAMBRIDGE, Mass., May 11, 2023 - TCR2 Therapeutics Inc. (Nasdaq: TCRR) (TCR2 or the Company), a clinical-stage cell therapy company with a pipeline of novel next-generation T cell therapies for patients suffering from solid tumors, today announced financial results for the first quarter ended

Amendment No. 1 to the Agreement and Plan of Merger, dated as of April 5, 2023 by and among Registrant, Adaptimmune Therapeutics plc and CM Merger Sub, Inc.

Exhibit 2.2 AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER This AMENDMENT NO. 1 TO AGREEMENT AND PLAN OF MERGER (this “Amendment”) is made and entered into as of April 5, 2023 by and among Adaptimmune Therapeutics plc (“Parent”), a public limited company incorporated in England and Wales, CM Merger Sub, Inc. (“Merger Sub”), a Delaware corporation and an indirect wholly-owned subsidiary of Parent,

TCRR / Tcr2 Therapeutics Inc / TANG CAPITAL PARTNERS LP - AMENDMENT NO. 2 Passive Investment

Securities and Exchange Commission Washington, DC 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. __)

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(a) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No.

As filed with the Securities and Exchange Commission on March 23, 2023

S-8 As filed with the Securities and Exchange Commission on March 23, 2023 Registration No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 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 001-38811 TCR2 Therapeutics Inc.

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) TCR2 Therapeutics Inc.

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): March 23, 2023 TCR2 THERAPEUTICS

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): March 23, 2023 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

TCR2 Therapeutics Reports Fourth Quarter and Full-Year 2022 Financial Results and Provides Corporate Update • TCR² and Adaptimmune announce strategic combination to create a preeminent cell therapy company focused on treating solid tumors • Following

Exhibit 99.1 TCR2 Therapeutics Reports Fourth Quarter and Full-Year 2022 Financial Results and Provides Corporate Update • TCR² and Adaptimmune announce strategic combination to create a preeminent cell therapy company focused on treating solid tumors • Following the expected Q2 2023 closing of the all-stock transaction, the combined company's cash runway is expected to extend into 2026 CAMBRIDGE,

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

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): March 10, 2023 TCR2 Therapeutics Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4152751 (State or Other Jurisdiction of Incorporation) (Commission F

Filed by Adaptimmune Therapeutics plc

Filed by Adaptimmune Therapeutics plc pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: TCR2 Therapeutics Inc.

Filed by Adaptimmune Therapeutics plc

425 1 tm238549d4425.htm 425 Filed by Adaptimmune Therapeutics plc pursuant to Rule 425 under the Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 under the Securities Exchange Act of 1934 Subject Company: TCR2 Therapeutics Inc. Commission File No.: 001-38811 This filing relates to the proposed merger of TCR2 Therapeutics Inc., a Delaware corporation (“TCR2”), with CM Merger Sub, Inc

Agreement and Plan of Merger, dated as of March 5, 2023, by and among TCR2 Therapeutics Inc., Adaptimmune Therapeutics plc and CM Merger Sub, Inc.

Exhibit 2.1    EXECUTION VERSION   AGREEMENT AND PLAN OF MERGER   BY AND AmONG   Adaptimmune therapeutics plc,   cm Merger sub, Inc.   AND   tcr2 therapeutics inc.       Dated as of March 5, 2023             TABLE OF CONTENTS   Section 1 THE MERGER 2 1.1 The Merger 2 1.2 Effective Time 2 1.3 Closing 2 1.4 Directors and Officers of the Surviving Corporation 3 1.5 Subsequent Actions 3 Section 2 CONV

Form of Executive Agreement Amendment

  Exhibit 10.3   FIRST AMENDMENT TO EMPLOYMENT AGREEMENT   This First Amendment to Employment Agreement (this “Amendment”) is made effective as of [] (the “Amendment Effective Date”), by and between TCR2 Therapeutics Inc., a Delaware corporation (the “Company”), and [] (the “Executive”). Capitalized terms used herein and not otherwise defined shall have the meanings ascribed to them in the Employm

C reating a preeminent cell therapy company Leading T he C ancer R evoluti on

Exhibit 99.2 C reating a preeminent cell therapy company Leading T he C ancer R evoluti on 2 Disclaimer This communication relates to the proposed transaction pursuant to the terms of the Agreement and Plan of Merger, dated March 5 , 2023 , by and among Adaptimmune Therapeutics plc (“Parent”), CM Merger Sub, Inc . (“Merger Sub”), and TCR² Therapeutics Inc . (the “Company”) . This communication inc

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): March 5, 2023 TCR2 THERAPEUTICS I

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): March 5, 2023 TCR2 THERAPEUTICS INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4752751 (State or Other Jurisdiction of Incorporation) (Commission Fi

Form of Voting and Support Agreement, dated as of March 5, 2023, by and among Adaptimmune, Registrant and certain stockholders of Registrant.

  Exhibit 10.1   EXECUTION VERSION VOTING AND SUPPORT AGREEMENT   This Voting and Support Agreement (this “Agreement”) is made and entered into as of March 5, 2023 (the “Agreement Date”), by and among (a) Adaptimmune Therapeutics PLC (“Parent”), a public company limited by shares incorporated in England and Wales, (b) TCR2 Therapeutics Inc. (the “Company”), a Delaware corporation and (c) [STOCKHOL

Form of Voting and Support Agreement, dated as of March 5, 2023, by and among Adaptimmune, TCR2 and certain shareholders of Adaptimmune.

Exhibit 10.2   EXECUTION VERSION   VOTING AND SUPPORT AGREEMENT   This Voting and Support Agreement (this “Agreement”) is made and entered into as of March 5, 2023 (the “Agreement Date”), by and among (a) Adaptimmune Therapeutics PLC (“Parent”), a public company limited by shares incorporated in England and Wales, (b) TCR2 Therapeutics Inc. (the “Company”), a Delaware corporation and (c) [SHAREHOL

Agreement and Plan of Merger, dated as of March 5, 2023, by and among Registrant, Adaptimmune Therapeutics plc and CM Merger Sub, Inc.

Exhibit 2.1    EXECUTION VERSION   AGREEMENT AND PLAN OF MERGER   BY AND AmONG   Adaptimmune therapeutics plc,   cm Merger sub, Inc.   AND   tcr2 therapeutics inc.       Dated as of March 5, 2023             TABLE OF CONTENTS   Section 1 THE MERGER 2 1.1 The Merger 2 1.2 Effective Time 2 1.3 Closing 2 1.4 Directors and Officers of the Surviving Corporation 3 1.5 Subsequent Actions 3 Section 2 CONV

Filed by TCR

Filed by TCR2 Therapeutics Inc. This communication is filed pursuant to Rule 425 under the United States Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 of the Securities Exchange Act of 1934 Subject Company: TCR2 Therapeutics Inc. (Commission File No. 001-38811) Date: March 6, 2023 This filing relates to the proposed merger of TCR2 Therapeutics Inc., a Delaware corporation (the “C

Filed by TCR

Filed by TCR2 Therapeutics Inc. This communication is filed pursuant to Rule 425 under the United States Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 of the Securities Exchange Act of 1934 Subject Company: TCR2 Therapeutics Inc. (Commission File No. 001-38811) Date: March 6, 2023 This filing relates to the proposed merger of TCR2 Therapeutics Inc., a Delaware corporation (the “C

COOKIE COMMS SCRIPT FOR WEBCAST

Exhibit 99.3 COOKIE COMMS SCRIPT FOR WEBCAST Slide 1 – JPM · Thank you, operator · Hello - this morning we issued a joint press release with TCR2 Therapeutics - announcing entry into an agreement for the strategic combination of our two companies. Slide 2 - JPM · In a second press release - we provided our Q4 and full year 2022 financial and business updates · I would ask you to review the full te

Adaptimmune and TCR² Therapeutics Announce Strategic Combination to Create a Preeminent Cell Therapy Company for Solid Tumors Compelling clinical data with clear paths to products and multiple near-term value-creating catalysts Complementary technolo

Exhibit 99.1 Adaptimmune and TCR² Therapeutics Announce Strategic Combination to Create a Preeminent Cell Therapy Company for Solid Tumors Compelling clinical data with clear paths to products and multiple near-term value-creating catalysts Complementary technology platforms designed to treat solid tumors which represents a substantial market opportunity largely unaddressed by cell therapies Follo

C reating a preeminent cell therapy company Leading T he C ancer R evoluti on

Exhibit 99.2 C reating a preeminent cell therapy company Leading T he C ancer R evoluti on 2 Disclaimer This communication relates to the proposed transaction pursuant to the terms of the Agreement and Plan of Merger, dated March 5 , 2023 , by and among Adaptimmune Therapeutics plc (“Parent”), CM Merger Sub, Inc . (“Merger Sub”), and TCR² Therapeutics Inc . (the “Company”) . This communication inc

COOKIE COMMS SCRIPT FOR WEBCAST

Exhibit 99.3 COOKIE COMMS SCRIPT FOR WEBCAST Slide 1 – JPM · Thank you, operator · Hello - this morning we issued a joint press release with TCR2 Therapeutics - announcing entry into an agreement for the strategic combination of our two companies. Slide 2 - JPM · In a second press release - we provided our Q4 and full year 2022 financial and business updates · I would ask you to review the full te

Form of Voting and Support Agreement, dated as of March 5, 2023, by and among Adaptimmune, TCR2 and certain stockholders of TCR2.

  Exhibit 10.1   EXECUTION VERSION VOTING AND SUPPORT AGREEMENT   This Voting and Support Agreement (this “Agreement”) is made and entered into as of March 5, 2023 (the “Agreement Date”), by and among (a) Adaptimmune Therapeutics PLC (“Parent”), a public company limited by shares incorporated in England and Wales, (b) TCR2 Therapeutics Inc. (the “Company”), a Delaware corporation and (c) [STOCKHOL

Form of Voting and Support Agreement, dated as of March 5, 2023, by and among Adaptimmune, TCR2 and certain shareholders of Adaptimmune.

Exhibit 10.2   EXECUTION VERSION   VOTING AND SUPPORT AGREEMENT   This Voting and Support Agreement (this “Agreement”) is made and entered into as of March 5, 2023 (the “Agreement Date”), by and among (a) Adaptimmune Therapeutics PLC (“Parent”), a public company limited by shares incorporated in England and Wales, (b) TCR2 Therapeutics Inc. (the “Company”), a Delaware corporation and (c) [SHAREHOL

Adaptimmune and TCR² Therapeutics Announce Strategic Combination to Create a Preeminent Cell Therapy Company for Solid Tumors Compelling clinical data with clear paths to products and multiple near-term value-creating catalysts Complementary technolo

Exhibit 99.1 Adaptimmune and TCR² Therapeutics Announce Strategic Combination to Create a Preeminent Cell Therapy Company for Solid Tumors Compelling clinical data with clear paths to products and multiple near-term value-creating catalysts Complementary technology platforms designed to treat solid tumors which represents a substantial market opportunity largely unaddressed by cell therapies Follo

Form of Executive Agreement Amendment.

  Exhibit 10.3   FIRST AMENDMENT TO EMPLOYMENT AGREEMENT   This First Amendment to Employment Agreement (this “Amendment”) is made effective as of [] (the “Amendment Effective Date”), by and between TCR2 Therapeutics Inc., a Delaware corporation (the “Company”), and [] (the “Executive”). Capitalized terms used herein and not otherwise defined shall have the meanings ascribed to them in the Employm

Filed by TCR

Filed by TCR2 Therapeutics Inc. This communication is filed pursuant to Rule 425 under the United States Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 of the Securities Exchange Act of 1934 Subject Company: TCR2 Therapeutics Inc. (Commission File No. 001-38811) Date: March 6, 2023 This filing relates to the proposed merger of TCR2 Therapeutics Inc., a Delaware corporation (the “C

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): March 5, 2023 TCR2 THERAPEUTICS I

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): March 5, 2023 TCR2 THERAPEUTICS INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4752751 (State or Other Jurisdiction of Incorporation) (Commission Fi

Filed by TCR

Filed by TCR2 Therapeutics Inc. This communication is filed pursuant to Rule 425 under the United States Securities Act of 1933 and deemed filed pursuant to Rule 14a-12 of the Securities Exchange Act of 1934 Subject Company: TCR2 Therapeutics Inc. (Commission File No. 001-38811) Date: March 6, 2023 This filing relates to the proposed merger of TCR2 Therapeutics Inc., a Delaware corporation (the “C

TCRR / Tcr2 Therapeutics Inc / TANG CAPITAL PARTNERS LP - AMENDMENT NO. 1 Passive Investment

SC 13G/A 1 tcrr28230sc13ga1.htm AMENDMENT NO. 1 Securities and Exchange Commission Washington, DC 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1)* TCR2 Therapeutics Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing of This Statement) Check th

TCRR / Tcr2 Therapeutics Inc / K2 PRINCIPAL FUND, L.P. Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G/A (Rule 13d-102) Amendment No. 1 Under the Securities Exchange Act of 1934 TCR2 THERAPEUTICS INC (Name of Issuer) Common Shares (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2022 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant

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): January 5, 2023 TCR2 THERAPEUTICS

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): January 5, 2023 TCR2 THERAPEUTICS INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4152751 (State or Other Jurisdiction of Incorporation) (Commission

TCR2 Therapeutics Announces Pipeline Priorities for 2023 • gavo-cel Phase 2 clinical trial now focused on ovarian cancer cohort with first meaningful durability data expected in 2H 2023 • Second-generation enhanced programs TC-510 and TC-520 prioriti

Exhibit 99.1 TCR2 Therapeutics Announces Pipeline Priorities for 2023 ? gavo-cel Phase 2 clinical trial now focused on ovarian cancer cohort with first meaningful durability data expected in 2H 2023 ? Second-generation enhanced programs TC-510 and TC-520 prioritized with TC-510 Phase 1 clinical trial ongoing and first meaningful objective response data expected in 2H 2023 ? Company to be streamlin

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): January 3, 2023 (January 1, 2023)

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): January 3, 2023 (January 1, 2023) TCR2 THERAPEUTICS INC. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4152751 (State or Other Jurisdiction of Incorpora

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO/A (Amendment No. 1) Tender Offer Statement Under Section 14(d)(l) or 13(e)(l) of the Securities Exchange Act of 1934 TCR2 THERAPEUTICS INC. (Name of Subject Company (

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO/A (Amendment No. 1) Tender Offer Statement Under Section 14(d)(l) or 13(e)(l) of the Securities Exchange Act of 1934 TCR2 THERAPEUTICS INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)) Options to Purchase Common Stock, Par Value $0.0001 Per Share (Title of Class of Securities) 87808K106 (CUSIP Num

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables SC TO-I/A (Form Type) TCR2 Therapeutics Inc.

TCR2 Therapeutics Reports Third Quarter 2022 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports Third Quarter 2022 Financial Results and Provides Corporate Update CAMBRIDGE, Mass., November 8, 2022 - TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage cell therapy company with a pipeline of novel T cell therapies for cancer patients suffering from solid tumors, today announced financial results for the third quarter ended September 30, 2022 and prov

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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 September 30, 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 001-38811 TCR2 Therapeutics Inc.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 8, 2022 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission

Form of Reminder Post to All Employees Regarding the Expiration of the Exchange Offer

Exhibit (a)(1)(M) Form of Reminder Post to All Employees Regarding the Expiration of the Exchange Offer From: Sarah Sardella To: All Employees Date: November 2, 2022 & November 10, 2022 If you are eligible to participate in the Stock Option Exchange Program, remember that the Exchange Offer and your withdrawal rights will expire at 11:59 p.

Option Exchange Company Meeting PPT Transcript

Exhibit (a)(5)(G) TCR2? October 19 Company Meeting Presentation Slide 1: Welcome everyone.

Option Exchange Education Session PPT

Exhibit (a)(5)(D) 2 TCR Option Exchange Program October 2022 1 1 Agenda ? Introductions and Overview ? The Basics ? How an Option Exchange Works ? Eligibility ? RSU Terms ? Considering Your Choice ? Important Disclaimers ? Q&A 2 [REDACTED AS NOT RELEVANT TO EXCHANGE OFFER] 3 Offer to Exchange Overview 2 ? Equity is an important component of your Total Rewards package at TCR ? Many stock options gr

Form of Email Notice Confirming Receipt of Election Form to Reject the Exchange Offer

Exhibit (a)(1)(Q) Form of Email Notice Confirming Receipt of Election Form to Reject the Exchange Offer From: Sarah Sardella Subject: Confirmation of Receipt of Option Exchange Election Form To: Eligible Employee (after election) Date: [DATE SENT] This message confirms that TCR2 Therapeutics, Inc.

Form of Final Reminder Post to All Employees Regarding the Expiration of the Exchange Offer

Exhibit (a)(1)(O) Form of Final Reminder Post to All Employees Regarding Expiration of the Exchange Offer From: Sarah Sardella To: All Employees Date: November 16, 2022 If you are eligible to participate in the Stock Option Exchange Program, today is the last day to complete your Election Form (or withdraw your election).

Form of Email to Eligible Employees with Eligible Options to access Election Form via DocuSign

Exhibit (a)(1)(E) Form of Email to Eligible Employees with Eligible Options to access Election Form via Docusign From: Sarah Sardella Subject: Please DocuSign: TCR2 Therapeutics Inc.

Form of Email Notice Confirming Receipt of Election Form to Participate in the Exchange Offer

Exhibit (a)(1)(P) Form of Email Notice Confirming Receipt of Election Form to Participate in the Exchange Offer From: Sarah Sardella Subject: Confirmation of Receipt of Option Exchange Election Form To: Eligible Employee (after election) Date: [DATE SENT] This message confirms that TCR2 Therapeutics, Inc.

Option Exchange Education Session PPT Transcript

Exhibit (a)(5)(E) TCR2? Option Exchange Tender Offer Presentation Slide 1: Welcome everyone to the TCR-squared option exchange program presentation.

Option Exchange Program Brochure

Exhibit (a)(5)(C) Your TCR2 Option Exchange Program offers employees who hold stock options with an exercise price of $10 or more the chance to exchange those options for fewer restricted stock units (RSU).

Notice of Withdrawal of Election Form

Exhibit (a)(1)(G) OPTION EXCHANGE?NOTICE OF WITHDRAWAL OF ELECTION FORM THE EXCHANGE OFFER AND YOUR WITHDRAWAL RIGHTS WILL EXPIRE AT 11:59 P.

Offer to Exchange Eligible Options for New Restricted Stock Units, dated October 19, 2022

Exhibit (a)(1)(A) TCR2 THERAPEUTICS INC. 100 BINNEY STREET, SUITE 710 CAMBRIDGE, MASSACHUSETTS 02142 OFFER TO EXCHANGE ELIGIBLE OPTIONS FOR NEW RESTRICTED STOCK UNITS October 19, 2022 1 TCR2 THERAPEUTICS INC. SUMMARY TERM SHEET?OVERVIEW OFFER TO EXCHANGE ELIGIBLE OPTIONS FOR NEW RESTRICTED STOCK UNITS This offer and withdrawal rights will expire at 11:59 p.m., Eastern Time, on November 16, 2022, u

Form of Email Notice Confirming Acceptance of Eligible Options

Exhibit (a)(1)(T) Form of Email Notice Confirming Acceptance of Eligible Options From: Sarah Sardella Subject: Confirmation of Acceptance of Eligible Options To: Eligible Participant Date: November 17, 2022 Thank you for submitting your Election Form pursuant to the Offer to Exchange Eligible Options for New Restricted Stock Units, dated October 19, 2022 (the ?Offer Documents?).

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO (Rule 13e-4) Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 TCR2 THERAPEUTICS INC. (Name of Subject Company (Issuer)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO (Rule 13e-4) Tender Offer Statement Under Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 TCR2 THERAPEUTICS INC. (Name of Subject Company (Issuer) and Filing Person (Offeror)) Options to Purchase Common Stock, Par Value $0.0001 Per Share (Title of Class of Securities) 87808K106 (CUSIP Number of

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables SC TO-I (Form Type) TCR2 Therapeutics Inc.

Option Exchange Transcripts

Exhibit (a)(5)(B) EquiTV | UWSO | TCR2 Therapeutics Underwater Stock Options (834 words) ? TCR2 Therapeutics? Option Exchange Program Overview ? Option Exchange Example ? The Tender Offering Title: TCR2 Therapeutics? Option Exchange Program Overview (381 words) Welcome to TCR2 Therapeutics? [Pronunciation: T-C-R-Squared Therapeutics] video on our option exchange program.

Form of Email Notice Confirming Rejection of Eligible Options

Exhibit (a)(1)(U) Form of Email Notice Confirming Rejection of Eligible Options From: Sarah Sardella Subject: Notice of Rejection of Eligible Options To: Eligible Participant Date: November 17, 2022 Thank you for submitting your Election Form pursuant to the Offer to Exchange Eligible Options for New Restricted Stock Units, dated October 19, 2022 (the ?Offer Documents?).

Form of Email Notice Confirming Receipt of Notice of Withdrawal of Election Form

Exhibit (a)(1)(R) Form of Email Notice Confirming Receipt of Notice of Withdrawal of Election Form From: Sarah Sardella Subject: Confirmation of Receipt of Notice of Withdrawal of Election Form To: Eligible Employee (after form received) Date: [DATE SENT] This message confirms that TCR2 Therapeutics Inc.

Form of Final Reminder Email to Eligible Employees with Eligible Options Regarding the Expiration of the Exchange Offer

Exhibit (a)(1)(N) Form of Final Reminder Post to Eligible Employees with Eligible Options Regarding the Expiration of the Exchange Offer From: Sarah Sardella Subject: *Final Reminder!* Stock Option Exchange Program Form Due TODAY by 11:59 pm ET To: All Eligible Employees with Eligible Options Date: November 16, 2022 Today is the last day to complete your Election Form (or withdraw your election) for the Stock Option Exchange Program.

Election Form

Exhibit (a)(1)(F) OPTION EXCHANGE?ELECTION FORM THIS OFFER AND YOUR WITHDRAWAL RIGHTS WILL EXPIRE AT 11:59 P.

Form of Announcement Email to All Employees

Exhibit (a)(1)(B) Form of Announcement Email to All Employees From: Garry Menzel Subject: TCR2 Therapeutics Stock Option Exchange Program To: All Employees Date: October 19, 2022 TRuCers, I am pleased to share with you that our Board of Directors has approved a voluntary stock option exchange program that will begin today, October 19, 2022.

Form of Post to All Employees Regarding Availability of a Recorded Version of the Exchange Offer Webinar

Exhibit (a)(1)(I) Form of Post to All Employees Regarding Availability of a Recorded Version of the Exchange Offer Webinar From: Sarah Sardella To: All Employees Date: October 20, 2022 If you are eligible to participate in the Stock Option Exchange Program, the recorded version of the educational webinar [link] is now available on Namely, under ?Resources > Stock Option Exchange Program.

Form of Reminder Email to Eligible Employees with Eligible Options Regarding the Expiration of the Exchange Offer

Exhibit (a)(1)(J) Form of Reminder Email to Eligible Employees with Eligible Options Regarding the Expiration of the Exchange Offer From: Sarah Sardella Subject: Reminder! Stock Option Exchange Program Form Due in [?] days To: All Eligible Employees with Eligible Options Date: [DATE], 2022 As you know, TCR2 Therapeutics Inc.

Form of Expiration Notice Email

Exhibit (a)(1)(S) Form of Expiration Notice Email From: Sarah Sardella Subject: Expiration of the Exchange Offer To: Eligible Employees with Eligible Options Date: November 17, 2022 The Exchange Offer described in the Offer to Exchange Eligible Options for New Restricted Stock Units, dated October 19, 2022 (the ?Offer Documents?), has expired, and no additional Election Forms or Notice of Withdrawal of Election Forms may be submitted.

Form of Email to Eligible Employees with Eligible Options Regarding the Final Exchange Offer Webinar

Exhibit (a)(1)(K) Form of Email to Eligible Employees with Eligible Options Regarding the Final Exchange Offer Webinar From: Sarah Sardella Subject: Reminder! Stock Option Exchange Program Webinar TODAY To: All Eligible Employees with Eligible Options Date: October 25, 2022 As you know, TCR2 Therapeutics Inc.

Form of Announcement Post to All Employees

Exhibit (a)(1)(C) Form of Announcement Post to All Employees From: Sarah Sardella To: All Employees Date: October 19, 2022 As you saw in Garry?s note, our Board of Directors has approved a voluntary stock option exchange program that will begin today, October 19, 2022.

Form of Reminder Email to Eligible Employees with Eligible Options Regarding the Exchange Offer Webinar

Exhibit (a)(1)(H) Form of Reminder Email to Eligible Employees with Eligible Options Regarding the Exchange Offer Webinar From: Sarah Sardella Subject: Reminder! Stock Option Exchange Program Webinar TODAY To: All Eligible Employees with Eligible Options Date: October 20, 2022 As you know, TCR2 Therapeutics Inc.

Form of Post to All Employees Regarding Education Session

Exhibit (a)(1)(L) Form of Post to All Employees Regarding Education Session From: Sarah Sardella To: All Employees Date: October 25, 2022 If you are eligible to participate in the Stock Option Exchange Program, the final live information session is TODAY at 2 pm ET! We encourage you to attend.

Option Exchange Company Meeting PPT

Exhibit (a)(5)(F) Engaging the TCR to Transform the Treatment of Solid Tumors New Equity Programs October 19, 2022 1 New Equity Programs 2 ? Equity is an important component of your Total Rewards package at TCR ? Granted as stock options and more recently, restricted stock units (RSUs) ? Equity serves to incentivize, motivate, and reward performance so we deliver on our strategic, operational, and

Option Exchange Presentations

Exhibit (a)(5)(A) Scene 1 (00m00s - 00m06s) Description: [Link] Words on screen: 2 TCR Therapeutics? Option Exchange Program Overview 2 2 Storyboard: TCR Therapeutics | UWSO | TCR Therapeutics? Option Exchange Program Overview (2022) Scene 2 (00m06s - 00m16s) Script: 2 Welcome to TCR Therapeutics? video on our option exchange program.

Form of Exchange Offer Instructions Email to Eligible Employees with Eligible Options

Exhibit (a)(1)(D) Form of Exchange Offer Instructions Email to Eligible Employees with Eligible Options From: Sarah Sardella Subject: TCR2 Therapeutics Inc.

Submission of Matters to a Vote of Security Holders

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 Act of 1934 Date of Report (Date of earliest event reported): October 14, 2022 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission File Num

gavo-cel Continues to Demonstrate Clinical Benefit in Solid Tumors with Additional RECIST Reponses in Ovarian Cancer and Mesothelioma - Completed Phase 1 clinical trial establishes gavo-cel monotherapy as the first anti-mesothelin cell therapy to dem

Exhibit 99.1 gavo-cel Continues to Demonstrate Clinical Benefit in Solid Tumors with Additional RECIST Reponses in Ovarian Cancer and Mesothelioma - Completed Phase 1 clinical trial establishes gavo-cel monotherapy as the first anti-mesothelin cell therapy to demonstrate tolerability and clinical benefit - Second RECIST partial response in ovarian cancer supports broad potential of gavo-cel - Cons

Forward Looking Statements This presentation has been prepared by TCR2 Therapeutics Inc. (“we,” “us,” or “our”) and contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal secur

EX-99.2 Phase 1 Dataset September 2022 Exhibit 99.2 Forward Looking Statements This presentation has been prepared by TCR2 Therapeutics Inc. (“we,” “us,” or “our”) and contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. Forward-looking statements are neither historical facts nor assurances of future perfo

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events

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 Act of 1934 Date of Report (Date of earliest event reported): September 28, 2022 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organization) (C

TCRR / Tcr2 Therapeutics Inc / K2 PRINCIPAL FUND, L.P. Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G (Rule 13d-102) Under the Securities Exchange Act of 1934 TCR2 THERAPEUTICS INC. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87808K106 (CUSIP Number) August 26, 2022 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant t

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitte

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. )

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 (Amendment No. ) Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): August 8, 2022 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

TCR2 Therapeutics Reports Second Quarter 2022 Financial Results and Provides Corporate Update - gavo-cel Phase 1 trial dataset anticipated in September 2022 - Initial TC-510 Phase 1 data anticipated in 2H 2022 - Expansion of manufacturing capacity an

Exhibit 99.1 TCR2 Therapeutics Reports Second Quarter 2022 Financial Results and Provides Corporate Update - gavo-cel Phase 1 trial dataset anticipated in September 2022 - Initial TC-510 Phase 1 data anticipated in 2H 2022 - Expansion of manufacturing capacity and commencement of gavo-cel clinical trial material production at ElevateBio BaseCamp CAMBRIDGE, Mass., August 8, 2022 - TCR2 Therapeutics

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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 June 30, 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 001-38811 TCR2 Therapeutics Inc.

TCR2 Therapeutics Appoints Industry and Finance Veteran Eric Sullivan as Chief Financial Officer

EX-99.1 2 d406715dex991.htm EX-99.1 Exhibit 99.1 TCR2 Therapeutics Appoints Industry and Finance Veteran Eric Sullivan as Chief Financial Officer CAMBRIDGE, Mass., June 27, 2022 – TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage cell therapy company with a pipeline of novel T cell therapies for patients suffering from solid tumors, today announced the appointment of Eric Sullivan as Chief F

Financial Statements and Exhibits

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): June 27, 2022 (June 27, 2022) TCR2 Therapeutics Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4152751 (State or Other Jurisdiction of Incorporation

Amended and Restated By-laws of the Registrant

Exhibit 3.2 AMENDED AND RESTATED BY-LAWS OF TCR2 THERAPEUTICS INC. (the “Corporation”) ARTICLE I Stockholders SECTION 1. Annual Meeting. The annual meeting of stockholders (any such meeting being referred to in these By-laws as an “Annual Meeting”) shall be held at the hour, date and place within or without the United States which is fixed by the Board of Directors, which time, date and place may

TCR2 Therapeutics Reports First Quarter 2022 Financial Results and Provides Corporate Update - Initiated Phase 2 expansion portion of the ongoing gavo-cel clinical trial - IND Clearance for Phase 1/2 clinical trial of TC-510 - 30 patients treated wit

EX-99.1 2 tcrr-ex991.htm EX-99.1 Exhibit 99.1 TCR2 Therapeutics Reports First Quarter 2022 Financial Results and Provides Corporate Update - Initiated Phase 2 expansion portion of the ongoing gavo-cel clinical trial - IND Clearance for Phase 1/2 clinical trial of TC-510 - 30 patients treated with gavo-cel in the expanded Phase 1 trial; dataset review in July 2022 - Updates anticipated in the secon

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 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 001-38811 TCR2 Therapeutics Inc.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): May 12, 2022 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-3 (Form Type) TCR2 Therapeutics Inc.

Power of Attorney (included on the signature page to this registration statement)

Table of Contents As filed with the Securities and Exchange Commission on March 22, 2022 Registration No.

Power of Attorney (included on the signature page to this registration statement)

Table of Contents As filed with the Securities and Exchange Commission on March 22, 2022 Registration No.

Filing Fee Table.

EX-FILING FEES 4 d327960dexfilingfees.htm EX-FILING FEES Exhibit 107 Calculation of Filing Fee Tables Form S-8 (Form Type) TCR2 Therapeutics Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered (1) Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate A

2022 Inducement Plan and forms of award agreements thereunder

Exhibit 10.13 TCR2 THERAPEUTICS INC. 2022 INDUCEMENT PLAN SECTION 1. GENERAL PURPOSE OF THE PLAN; DEFINITIONS The name of the plan is the TCR2 Therapeutics Inc. 2022 Inducement Plan (the ?Plan?). The purpose of the Plan is to encourage and enable TCR2 Therapeutics Inc. (the ?Company?) to grant equity awards to induce highly-qualified prospective officers and employees to accept employment and prov

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): March 22, 2022 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

Power of Attorney (included on signature page to this Registration Statement).

As filed with the Securities and Exchange Commission on March 22, 2022 Registration No.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 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 001-38811 TCR2 Therapeutics Inc.

TCR2 Therapeutics Reports Fourth Quarter 2021 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports Fourth Quarter 2021 Financial Results and Provides Corporate Update CAMBRIDGE, Mass., March 22, 2022 - TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage cell therapy company with a pipeline of novel T cell therapies for cancer patients suffering from solid tumors, today announced financial results for the fourth quarter ended December 31, 2021 and provi

TCRR / Tcr2 Therapeutics Inc / TANG CAPITAL PARTNERS LP Passive Investment

Securities and Exchange Commission Washington, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No.

JOINT FILING AGREEMENT

EX-99.1 2 ex991.htm EXHIBIT 99.1 Exhibit 99.1 JOINT FILING AGREEMENT In accordance with Rule 13d-1(k)(1) promulgated under the Securities Exchange Act of 1934, the undersigned agree to the joint filing of a Statement on Schedule 13G (including any and all amendments thereto) with respect to the Common Stock, $0.0001 par value per share, of TCR2 Therapeutics Inc. and further agree to the filing of

Joint Filing Agreement

EX-99.1 2 tm226094d36ex99-1.htm EXHIBIT 99.1 Exhibit 99.1 Joint Filing Agreement In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), the undersigned hereby agree to the joint filing on behalf of each of them of a Statement on Schedule 13G (including any and all amendments thereto, the “Schedule 13G”) relating to the Common Stock, at $0.00

TCRR / Tcr2 Therapeutics Inc / Redmile Group, LLC - SC 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 4) TCR2 THERAPEUTICS INC. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2021 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pur

Current Report

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 22, 2021 (November 18, 2021) TCR2 Therapeutics Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4152751 (State or Other Jurisdiction of Incor

TCRR / Tcr2 Therapeutics Inc / WELLINGTON MANAGEMENT GROUP LLP - SEC SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1 )* TCR2 Therapeutics Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87808K106 (CUSIP Number) October 29, 2021 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 10, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commissio

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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 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 001-38811 TCR2 Therapeutics Inc.

TCR2 Therapeutics Reports Third Quarter 2021 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports Third Quarter 2021 Financial Results and Provides Corporate Update CAMBRIDGE, Mass., November 10, 2021 - TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage cell therapy company with a pipeline of novel T cell therapies for cancer patients suffering from solid tumors, today announced financial results for the third quarter ended September 30, 2021 and pro

Financial Statements and Exhibits, Costs Associated with Exit or Disposal Activities

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 1, 2021 TCR2 Therapeutics Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4152751 (State or Other Jurisdiction of Incorporation) (Commission

TCR2 Therapeutics Announces Expansion of U.S. Manufacturing Capacity - Second clean room at ElevateBio BaseCamp will expand cGMP capacity for clinical trials in 2022 - Future network to focus on TCR2 manufacturing center of excellence in Rockville, M

Exhibit 99.1 TCR2 Therapeutics Announces Expansion of U.S. Manufacturing Capacity - Second clean room at ElevateBio BaseCamp will expand cGMP capacity for clinical trials in 2022 - Future network to focus on TCR2 manufacturing center of excellence in Rockville, MD - Strategy optimizes efficiencies and simplifies regulatory pathway CAMBRIDGE, Mass., November 1, 2021 - TCR2 Therapeutics Inc. (Nasdaq

Financial Statements and Exhibits, Other Events

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 Act of 1934 Date of Report (Date of earliest event reported): October 25, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organization) (Com

TCR2 Therapeutics Announces Clinical Trial Collaboration Agreement with Bristol Myers Squibb to Evaluate Gavo-cel in Combination with Opdivo® and Yervoy® in Mesothelin-Expressing Solid Tumors

Exhibit 99.1 TCR2 Therapeutics Announces Clinical Trial Collaboration Agreement with Bristol Myers Squibb to Evaluate Gavo-cel in Combination with Opdivo? and Yervoy? in Mesothelin-Expressing Solid Tumors CAMBRIDGE, Mass., October 25, 2021 - TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage cell therapy company with a pipeline of novel T cell therapies for patients suffering from solid tumor

Submission of Matters to a Vote of Security Holders

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 Act of 1934 Date of Report (Date of earliest event reported): October 22, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission File Num

TCR2 Therapeutics Reviews Pipeline and Strategy at R&D Day - gavo-cel recommended Phase 2 dose (RP2D) identification before year-end - Anticipated IND filing for TC-510 in 1Q22 - Identification of CD70-targeted lead candidate - Anticipated allogeneic

Exhibit 99.1 TCR2 Therapeutics Reviews Pipeline and Strategy at R&D Day - gavo-cel recommended Phase 2 dose (RP2D) identification before year-end - Anticipated IND filing for TC-510 in 1Q22 - Identification of CD70-targeted lead candidate - Anticipated allogeneic program lead candidate in 2022 - Expansion of platform into autoimmune diseases with TRuC Tregs - TCR2 to host a webcast on Wednesday, O

Forward Looking Statements This presentation has been prepared by TCR2 Therapeutics Inc. (“we,” “us,” or “our”) and contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal secur

R&D Day October 2021 Exhibit 99.2 Forward Looking Statements This presentation has been prepared by TCR2 Therapeutics Inc. (?we,? ?us,? or ?our?) and contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. Forward-looking statements are neither historical facts nor assurances of future performance. Instead, t

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events

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 Act of 1934 Date of Report (Date of earliest event reported): October 20, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organization) (Com

TCR2 Therapeutics Announces Positive Interim Results from Ongoing Phase 1/2 Trial of Gavo-cel for Treatment Refractory Mesothelin-Expressing Solid Tumors - Clinical activity observed in all three mesothelin-expressing tumor types treated - Gavo-cel d

Exhibit 99.1 TCR2 Therapeutics Announces Positive Interim Results from Ongoing Phase 1/2 Trial of Gavo-cel for Treatment Refractory Mesothelin-Expressing Solid Tumors - Clinical activity observed in all three mesothelin-expressing tumor types treated - Gavo-cel disease control rate (DCR) 81% with tumor regression in 15 of 16 evaluable patients - Overall response rate (ORR) 31% in patients infused

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events

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 Act of 1934 Date of Report (Date of earliest event reported): September 17, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organization) (C

Forward Looking Statements This presentation has been prepared by TCR2 Therapeutics Inc. (“we,” “us,” or “our”) and contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal secur

EX-99.2 3 d212739dex992.htm EX-99.2 gavo-cel Phase 1/2 Clinical Update September 2021 Exhibit 99.2 Forward Looking Statements This presentation has been prepared by TCR2 Therapeutics Inc. (“we,” “us,” or “our”) and contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. Forward-looking statements are neither

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A (Rule 14a--101) INFORMATION REQUIRED IN PROXY STATEMENT SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A (Rule 14a-101) INFORMATION REQUIRED IN PROXY STATEMENT SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use of

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A (Rule 14a-101) INFORMATION REQUIRED IN PROXY STATEMENT SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A (Rule 14a?-101) INFORMATION REQUIRED IN PROXY STATEMENT SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ? Filed by a Party other than the Registrant ? Check the appropriate box: ? Preliminary Proxy Statement ? Confidential, for Use o

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

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): August 26, 2021 (August 24, 2021) TCR2 Therapeutics Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-38811 47-4152751 (State or Other Jurisdiction of Incorpora

TCR2 Therapeutics Announces Renowned Translational Medicine Leader Priti Hegde Joins Its Board of Directors

TCR2 Therapeutics Announces Renowned Translational Medicine Leader Priti Hegde Joins Its Board of Directors CAMBRIDGE, Mass.

TCR2 Therapeutics Reports Second Quarter 2021 Financial Results and Provides Corporate Update - New clinical data from gavo-cel Phase 1 trial to be presented at European Society of Medical Oncology (ESMO) - Remain on track to identify recommended Pha

Exhibit 99.1 TCR2 Therapeutics Reports Second Quarter 2021 Financial Results and Provides Corporate Update - New clinical data from gavo-cel Phase 1 trial to be presented at European Society of Medical Oncology (ESMO) - Remain on track to identify recommended Phase 2 dose (RP2D) for gavo-cel in 2021 - TCR2 to host virtual R&D Day on October 20, 2021 to highlight emerging pipeline CAMBRIDGE, Mass.,

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): August 5, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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 June 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 001-38811 TCR2 Therapeutics Inc.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 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 001-38811 TCR2 Therapeutics Inc.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): May 13, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

Lease Agreement, dated as of March 23, 2021, by and between ARE-Maryland No. 31, LLC and the Registrant

LEASE AGREEMENT THIS LEASE AGREEMENT (“this Lease”) is made as of this 23rd day of March, 2021 between ARE-MARYLAND NO.

TCR2 Therapeutics Reports First Quarter 2021 Financial Results and Provides Corporate Update

EX-99.1 2 tcrr-ex9916.htm EX-99.1 Exhibit 99.1 TCR2 Therapeutics Reports First Quarter 2021 Financial Results and Provides Corporate Update CAMBRIDGE, Mass., May 13, 2021 - TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage cell therapy company with a pipeline of novel T cell therapies for patients suffering from cancer, today announced financial results for the first quarter ended March 31,

Financial Statements and Exhibits, Other Events

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): April 30, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organizatio

CALCULATION OF REGISTRATION FEE Title of Each Class of Securities to be Registered Proposed Maximum Aggregate Offering Price Amount of Registration Fee(1) Common Stock, $0.0001 par value $100,000,000 $10,910

424B5 Table of Contents Filed Pursuant to Rule 424(b)(5) Registration No. 333-254355 CALCULATION OF REGISTRATION FEE Title of Each Class of Securities to be Registered Proposed Maximum Aggregate Offering Price Amount of Registration Fee(1) Common Stock, $0.0001 par value $100,000,000 $10,910 (1) Calculated in accordance with Rules 456(b) and 457(r) of the Securities Act of 1933, as amended. This “

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Creation of a Direct Financial Obligation or an Obligation under an Off-Balance Sheet Arrangement of a Registrant

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): March 23, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

Amendment No. 1 to Amended and Restated By-laws of the Registrant (Incorporated by reference to Exhibit 3.3 to the Registrant’s Annual Report on 10-K (File No. 001-38811) filed with the Securities and Exchange Commission on March 16, 2021)

Exhibit 3.3 AMENDMENT NO. 1 TO THE AMENDED AND RESTATED BY-LAWS OF TCR2 THERAPEUTICS INC. (THE ?COMPANY?) Section 8 of Article VI of the Amended and Restated By-laws of the Company (the ?By-laws?), is hereby amended and restated in its entirety to read as follows: ?SECTION 8. Exclusive Jurisdiction of Delaware Courts or the United States Federal District Courts. Unless the Corporation consents in

Form of Subordinated Indenture between the Registrant and one or more trustees to be named (including Form of Subordinated Note) (incorporated by reference to Exhibit 4.6 to the Registrant’s Registration Statement on Form S-3 (File No. 333-254355) filed with the SEC on March 16, 2021)

Exhibit 4.6 TCR2 THERAPEUTICS INC., Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [?], 202[?] Subordinated Debt Securities TABLE OF CONTENTS1 ARTICLE 1 DEFINITIONS Section 1.01 Definitions of Terms ARTICLE 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES Section 2.0 Designation and Terms of Securities Section 2.02 Form of Securities and Trustee?s Certificate Se

- S-8

As filed with the Securities and Exchange Commission on March 16, 2021 Registration No.

Form of Senior Indenture between the Registrant and one or more trustees to be named (including Form of Senior Note) (incorporated by reference to Exhibit 4.5 to the Registrant’s Registration Statement on Form S-3 (File No. 333-254355) filed with the SEC on March 16, 2021)

Exhibit 4.5 TCR2 THERAPEUTICS INC., Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [?], 202[?] Senior Debt Securities TABLE OF CONTENTS1 ARTICLE 1 DEFINITIONS Section 1.01 Definitions of Terms ARTICLE 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES Section 2.01 Designation and Terms of Securities Section 2.02 Form of Securities and Trustee?s Certificate Section

- S-3ASR

Table of Contents As filed with the Securities and Exchange Commission on March 16, 2021.

Description of Registrant’s Securities

Exhibit 4.4 Description of the Registrant’s Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934, as amended The common stock, par value $0.0001 per share (“Common Stock”), of TCR2 Therapeutics Inc. (“TCR2,” “we,” or “our”) is registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). The following description sets forth cert

Annual Report - 10-K

0-K? UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 2020 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 001-38811 TCR2 Therapeutics Inc.

TCR2 Therapeutics Reports Fourth Quarter and Full Year 2020 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports Fourth Quarter and Full Year 2020 Financial Results and Provides Corporate Update - Preliminary safety, efficacy and translational data from gavo-cel Phase 1 trial at AACR 2021 - Preclinical data on autologous CD70 and allogeneic mesothelin TRuC data at AACR 2021 - Raised gross proceeds of $140M in a follow-on offering in January; extended cash runway into 20

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): March 11, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 2) TCR2 THERAPEUTICS INC. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 2) TCR2 THERAPEUTICS INC. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2020 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pur

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1)* TCR2 Therapeutics Inc.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No.

Joint Filing Agreement

EX-99.1 2 tm215825d22ex99-1.htm EXHIBIT 99.1 Exhibit 99.1 Joint Filing Agreement In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), the undersigned hereby agree to the joint filing on behalf of each of them of a Statement on Schedule 13G (including any and all amendments thereto, the “Schedule 13G”) relating to the Common Stock, at $0.00

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* TCR2 Therapeutics Inc. (Name of Issuer) Common stock, par value US$0.0001 per share (Title of Class of S

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* TCR2 Therapeutics Inc. (Name of Issuer) Common stock, par value US$0.0001 per share (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2020 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate t

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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 Act of 1934 Date of Report (Date of earliest event reported): February 3, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organization) (Com

TCR2 Therapeutics Announces Commercial Cell Therapy Leader Shawn Tomasello Joins its Board of Directors

EX-99.1 Exhibit 99.1 TCR2 Therapeutics Announces Commercial Cell Therapy Leader Shawn Tomasello Joins its Board of Directors CAMBRIDGE, Mass., February 4, 2021 — TCR2 Therapeutics Inc. (Nasdaq: TCRR) (“TCR2” or the “Company”), a clinical-stage immunotherapy company with a pipeline of novel T cell therapies for patients suffering from cancer, today announced the appointment of Shawn Tomasello to it

TCR2 Therapeutics Announces Pricing of Public Offering of $140.0 Million of Common Stock

Exhibit 99.2 TCR2 Therapeutics Announces Pricing of Public Offering of $140.0 Million of Common Stock CAMBRIDGE, Mass., Jan. 19, 2021 (GLOBE NEWSWIRE) — TCR2 Therapeutics Inc. (Nasdaq: TCRR) (“TCR2” or the “Company”), a clinical-stage immunotherapy company with a pipeline of novel T cell therapies for patients suffering from cancer, today announced the pricing of an underwritten public offering of

Underwriting Agreement, dated January 19, 2021, by and among TCR2 Therapeutics Inc., Goldman Sachs & Co. LLC, Jefferies LLC, Piper Sandler & Co. and BMO Capital Markets, as representatives of the several underwriters named therein.

EX-1.1 2 d845914dex11.htm EX-1.1 Exhibit 1.1 4,590,164 Shares TCR2 Therapeutics Inc. UNDERWRITING AGREEMENT January 19, 2021 GOLDMAN SACHS & CO. LLC JEFFERIES LLC PIPER SANDLER & CO. BMO CAPITAL MARKETS CORP. As Representatives of the several Underwriters c/o Goldman Sachs & Co. LLC 200 West Street New York, New York 10282 c/o JEFFERIES LLC 520 Madison Avenue New York, New York 10022 c/o PIPER SAN

TCR2 Therapeutics Announces Proposed Public Offering of Common Stock

EX-99.1 Exhibit 99.1 TCR2 Therapeutics Announces Proposed Public Offering of Common Stock CAMBRIDGE, Mass., Jan. 19, 2021 (GLOBE NEWSWIRE) — TCR2 Therapeutics Inc. (Nasdaq: TCRR) (“TCR2” or the “Company”), a clinical-stage immunotherapy company with a pipeline of novel T cell therapies for patients suffering from cancer, today announced that it has commenced an underwritten public offering of $125

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events - 8-K

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 Act of 1934 Date of Report (Date of earliest event reported): January 19, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organization) (Com

4,590,164 Shares Common Stock

424B5 Table of Contents As Filed Pursuant to Rule 424(b)(5) Registration No. 333-236965 PROSPECTUS SUPPLEMENT (To prospectus dated April 28, 2020) 4,590,164 Shares Common Stock We are offering 4,590,164 shares of our common stock, par value $0.0001 per share. Our common stock is listed on The Nasdaq Global Select Market under the symbol “TCRR.” On January 19, 2021, the closing price for our common

SUBJECT TO COMPLETION, DATED JANUARY 19, 2021

424B5 Table of Contents As Filed Pursuant to Rule 424(b)(5) Registration No. 333-236965 The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement relating to these securities has been declared effective by the Securities and Exchange Commission. This preliminary prospectus supplement and the accompanying prospectus are not an offer to se

Financial Statements and Exhibits, Results of Operations and Financial Condition, Other Events - 8-K

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 Act of 1934 Date of Report (Date of earliest event reported): January 19, 2021 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organization) (Com

- S-3MEF

S-3MEF As filed with the Securities and Exchange Commission on January 19, 2021. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 47-4152751 (State or other jurisdiction of incorporation or organization)

SCHEDULE 13G

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* TCR2 Therapeutics Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2020 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this S

TCR2 Announces RECIST Response in Ovarian Cancer from Ongoing Phase 1/2 Trial of TC-210 in Treatment Refractory Mesothelin-Expressing Solid Tumors - TC-210 induced tumor regression in all of the first eight patients - Ovarian cancer patient achieved

EX-99.1 Exhibit 99.1 TCR2 Announces RECIST Response in Ovarian Cancer from Ongoing Phase 1/2 Trial of TC-210 in Treatment Refractory Mesothelin-Expressing Solid Tumors - TC-210 induced tumor regression in all of the first eight patients - Ovarian cancer patient achieved confirmed RECIST partial response (PR) - Overall response rate (ORR) 50% in patients infused with TC-210 and lymphodepletion - Co

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events - 8-K

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 Act of 1934 Date of Report (Date of earliest event reported): December 14, 2020 (December 13, 2020) TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation

Forward Looking Statements This presentation has been prepared by TCR2 Therapeutics Inc. (“we,” “us,” or “our”) and contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal secur

EX-99.2 Interim Clinical Data from Gavo-cel (TC-210) Patients December 2020 Exhibit 99.2 Forward Looking Statements This presentation has been prepared by TCR2 Therapeutics Inc. (“we,” “us,” or “our”) and contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995 and other federal securities laws. Forward-looking statements are neither historical

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 12, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commissio

TCR2 Therapeutics Reports Third Quarter 2020 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports Third Quarter 2020 Financial Results and Provides Corporate Update - Consistent progress of TC-210 with interim update from Phase 1/2 trial anticipated in 4Q20 - Additional clinical sites to include UCSF Medical Center and Princess Margaret Cancer Centre in the TC-210 Phase 1/2 clinical trial - Agreement with ElevateBio for additional manufacturing capacity f

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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 September 30, 2020 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 001-38811 TCR2 Therapeutics Inc.

Submission of Matters to a Vote of Security Holders - 8-K

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 Act of 1934 Date of Report (Date of earliest event reported): October 1, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission File Numb

- DEFA14A

DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Pro

- DEF 14A

DEF 14A Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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 June 30, 2020 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 001-38811 TCR2 Therapeutics Inc.

Financial Statements and Exhibits, Results of Operations and Financial Condition - 8-K 20Q2 EARNINGS RELEASE

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): August 12, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission

TCR2 Therapeutics Reports Second Quarter 2020 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports Second Quarter 2020 Financial Results and Provides Corporate Update - TC-210 patient with partial response confirmed by independent central review and tumor regression improved further from 42% to 75% - Began dosing of TC-110 in the Phase 1/2 trial for patients with CD19+ NHL or adult ALL - Addition of MD Anderson Cancer Center, a leading clinical site, to th

TCR 2 Therapeutics Announces Proposed Public Offering of Common Stock

EX-99.1 Exhibit 99.1 TCR 2 Therapeutics Announces Proposed Public Offering of Common Stock CAMBRIDGE, Mass., July 27, 2020 - TCR2 Therapeutics Inc. (Nasdaq: TCRR) (“TCR2” or the “Company”), a clinical-stage immunotherapy company with a pipeline of novel T cell therapies for patients suffering from cancer, today announced that it has commenced an underwritten public offering of 6,000,000 shares of

Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Other Events

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 Act of 1934 Date of Report (Date of earliest event reported): July 27, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation or organization) (Commis

TCR 2 Therapeutics Announces Pricing of Public Offering of Common Stock

EX-99.2 Exhibit 99.2 TCR 2 Therapeutics Announces Pricing of Public Offering of Common Stock CAMBRIDGE, Mass., July 28, 2020 — TCR2 Therapeutics Inc. (Nasdaq: TCRR) (“TCR2” or the “Company”), a clinical-stage immunotherapy company with a pipeline of novel T cell therapies for patients suffering from cancer, today announced the pricing of an underwritten public offering of 8,000,000 shares of its c

Underwriting Agreement, dated July 28, 2020, by and among TCR2 Therapeutics Inc., Jefferies LLC, SVB Leerink LLC, Piper Sandler & Co. and BMO Capital Markets, as representatives of the several underwriters named therein.

EX-1.1 Exhibit 1.1 8,000,000 Shares TCR2 Therapeutics Inc. UNDERWRITING AGREEMENT July 28, 2020 JEFFERIES LLC SVB LEERINK LLC PIPER SANDLER & CO. BMO CAPITAL MARKETS CORP. As Representatives of the several Underwriters c/o JEFFERIES LLC 520 Madison Avenue New York, New York 10022 c/o SVB LEERINK LLC One Federal Street, 37th Floor Boston, Massachusetts 02110 c/o PIPER SANDLER & CO. 800 Nicollet Mal

8,000,000 Shares Common Stock

424B5 Table of Contents As Filed Pursuant to Rule 424(b)(5) Registration No. 333-236965 PROSPECTUS SUPPLEMENT (To prospectus dated April 28, 2020) 8,000,000 Shares Common Stock We are offering 8,000,000 shares of our common stock, par value $0.0001 per share. Our common stock is listed on The Nasdaq Global Select Market under the symbol “TCRR.” On July 28, 2020, the closing price for our common st

TCR2 Therapeutics Announces RECIST Responses with First TC-210 Dose Tested in Advanced Mesothelin-Expressing Solid Tumors - TC-210 TRuC-T cell monotherapy induced tumor regression in first five patients - Two RECIST unconfirmed partial responses and

EX-99.1 Exhibit 99.1 TCR2 Therapeutics Announces RECIST Responses with First TC-210 Dose Tested in Advanced Mesothelin-Expressing Solid Tumors - TC-210 TRuC-T cell monotherapy induced tumor regression in first five patients - Two RECIST unconfirmed partial responses and two patients with stable disease through six months - Manageable toxicity profile, with only one patient exhibiting TC-210-relate

SUBJECT TO COMPLETION, DATED JULY 27, 2020

424B5 Table of Contents As Filed Pursuant to Rule 424(b)(5) Registration No. 333-236965 The information in this prospectus is not complete and may be changed. These securities may not be sold until the registration statement filed with the Securities and Exchange Commission is effective. This prospectus is not an offer to sell nor does it seek an offer to buy these securities in any jurisdiction w

Forward Looking Statements 2 This presentation has been prepared by TCR Therapeutics Inc. (“we,” “us,” or planned Phase 1 clinical trial of TC-110; the risk that the results from the Phase “our”) and contains forward-looking statements within the mea

EX-99.2 Exhibit 99.2 Presentation of Clinical Data from First Cohort of TC-210 Patients Trial ongoing with additional patients enrolled and treatedExhibit 99.2 Presentation of Clinical Data from First Cohort of TC-210 Patients Trial ongoing with additional patients enrolled and treated Forward Looking Statements 2 This presentation has been prepared by TCR Therapeutics Inc. (“we,” “us,” or planned

Regulation FD Disclosure, Financial Statements and Exhibits, Other Events - 8-K

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): July 26, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fi

Quarterly Report - 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 2020 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 001-38811 TCR2 Therapeutics Inc.

TCR2 Therapeutics Reports First Quarter 2020 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports First Quarter 2020 Financial Results and Provides Corporate Update • Continued progress on treatment of TC-210 patients with interim update from Phase 1 portion of Phase 1/2 clinical trial anticipated in mid-2020 • Continued progress of TC-110 with initiation of leading clinical sites participating in Phase 1/2 clinical trial that include Sarah Cannon Researc

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): May 14, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

TCR2 Therapeutics Announces Veteran Finance Executive Stephen Webster Joins its Board of Directors

Exhibit 99.1 TCR2 Therapeutics Announces Veteran Finance Executive Stephen Webster Joins its Board of Directors CAMBRIDGE, Mass., May 4, 2020 - TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage immunotherapy company developing the next generation of novel T cell therapies for patients suffering from cancer, today announced the appointment of Stephen Webster to its Board of Directors. With ne

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): April 30, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

-

CORRESP TCR2 Therapeutics Inc. 100 Binney Street, Suite 710 Cambridge, MA 02142 April 24, 2020 Via EDGAR Transmission United States Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Re: TCR2 Therapeutics Inc.: Registration Statement on Form S-3 filed March 6, 2020 (File No. 333-236965) Ladies and Gentlemen: Pursuant to Rule 461 under the S

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits

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): April 13, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

TCR2 Therapeutics Announces Immuno-Oncology Pioneer Dr. Axel Hoos Joins its Board of Directors

Exhibit 99.1 TCR2 Therapeutics Announces Immuno-Oncology Pioneer Dr. Axel Hoos Joins its Board of Directors CAMBRIDGE, Mass., April 15, 2020 - TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage immunotherapy company developing the next generation of novel T cell therapies for patients suffering from cancer, today announced the appointment of Axel Hoos, M.D., Ph.D., to its Board of Directors.

TCRR / TCR2 THERAPEUTICS INC. S-3/A - - S-3/A

S-3/A As filed with the Securities and Exchange Commission on March 30, 2020. Registration No. 333-236965 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Amendment No. 1 to FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 47-4152751 (State or other jurisdiction of incorpor

TCRR / TCR2 THERAPEUTICS INC. S-8 - - S-8

S-8 As filed with the Securities and Exchange Commission on March 30, 2020 Registration No.

TCRR / TCR2 THERAPEUTICS INC. 10-K - Annual Report - 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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, 2019 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 001-38811 TCR2 Therapeutics Inc.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): March 30, 2020 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

Description of Registrant’s Securities

Exhibit 4.4 Description of the Registrant’s Securities Registered Pursuant to Section 12 of the Securities Exchange Act of 1934, as amended The common stock, par value $0.0001 per share (“Common Stock”), of TCR2 Therapeutics Inc. (“TCR2,” “we,” or “our”) is registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”). The following description sets forth cert

TCR2 Therapeutics Reports Fourth Quarter and Full Year 2019 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports Fourth Quarter and Full Year 2019 Financial Results and Provides Corporate Update • Company initiated Phase 1/2 clinical trial for TC-110, its lead hematological malignancy candidate • Interim update from Phase 1 portion of TC-210 Phase 1/2 trial anticipated in 2Q20 and Phase 1/2 trial of TC-110 in 2H20 • TCR2 manufacturing suite fully operational in Stevenag

Form S-3

S-3 Table of Contents As filed with the Securities and Exchange Commission on March 6, 2020.

Form of Subordinated Indenture between the Registrant and one or more trustees to be named (including Form of Subordinated Note)

EX-4.6 Exhibit 4.6 TCR2 THERAPEUTICS INC., Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [●], 202[●] Subordinated Debt Securities TABLE OF CONTENTS1 ARTICLE 1 DEFINITIONS 1 Section 1.01 Definitions of Terms 1 ARTICLE 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES 5 Section 2.01 Designation and Terms of Securities 5 Section 2.02 Form of Securities and Trustee’

Open Market Sale AgreementSM by and between the Registrant and Jefferies LLC, dated March 6, 2020

EX-1.2 Exhibit 1.2 OPEN MARKET SALE AGREEMENTSM March 6, 2020 JEFFERIES LLC 520 Madison Avenue New York, New York 10022 Ladies and Gentlemen: TCR2 Therapeutics Inc., a Delaware corporation (the “Company”), proposes, subject to the terms and conditions stated herein, to issue and sell from time to time through Jefferies LLC, as sales agent and/or principal (the “Agent”), shares of the Company’s com

Form of Senior Indenture between the Registrant and one or more trustees to be named (including Form of Senior Note)

EX-4.5 Exhibit 4.5 TCR2 THERAPEUTICS INC., Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [●], 202[●] Senior Debt Securities TABLE OF CONTENTS1 ARTICLE 1 DEFINITIONS 1 Section 1.01 Definitions of Terms 1 ARTICLE 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES 5 Section 2.01 Designation and Terms of Securities 5 Section 2.02 Form of Securities and Trustee’s Cert

TCRR / TCR2 THERAPEUTICS INC. / Redmile Group, LLC - SCHEDULE 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 (Amendment No. 1) TCR2 THERAPEUTICS INC. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2019 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pur

TCRR / TCR2 THERAPEUTICS INC. / Arrowpoint Asset Management, LLC - SCHEDULE 13G HOLDINGS REPORT Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No.

TCRR / TCR2 THERAPEUTICS INC. / Upnorth Investment Ltd - SC 13G/A Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* TCR2 Therapeutics Inc. (Name of Issuer) Common stock, par value US$0.0001 per share (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2019 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate t

TCRR / TCR2 THERAPEUTICS INC. / F2 Capital I 2015 Ltd - SC 13G Passive Investment

SC 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. ) TCR2 THERAPEUTICS INC. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87808K106 (CUSIP Number) December 31, 2019 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule

November 12, 2019

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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 September 30, 2019 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 001-38811 TCR2 Therapeutics Inc.

TCR2 Therapeutics Reports Third Quarter 2019 Financial Results and Provides Corporate Update

Exhibit 99.1 TCR2 Therapeutics Reports Third Quarter 2019 Financial Results and Provides Corporate Update CAMBRIDGE, Mass., November 12, 2019 - TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage immunotherapy company developing the next generation of novel T cell therapies for patients suffering from cancer, today announced financial results for the third quarter ended September 30, 2019 and

Financial Statements and Exhibits, Results of Operations and Financial Condition

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 12, 2019 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commissio

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, Financial Statements and Exhibits, Submission of Matters to a Vote of Security Holders

8-K 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 Act of 1934 Date of Report (Date of earliest event reported): October 10, 2019 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission File

TCRR / TCR2 THERAPEUTICS INC. DEFA14A - - DEFA14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A (Rule 14a-101) INFORMATION REQUIRED IN PROXY STATEMENT SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of

TCRR / TCR2 THERAPEUTICS INC. DEF 14A - - DEF 14A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A (Rule 14a-101) INFORMATION REQUIRED IN PROXY STATEMENT SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of

August 9, 2019

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 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 June 30, 2019 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 001-38811 TCR2 Therapeutics Inc.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): August 8, 2019 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission F

TCR2 Therapeutics Reports Second Quarter 2019 Financial Results and Provides Corporate Update

TCR2 Therapeutics Reports Second Quarter 2019 Financial Results and Provides Corporate Update • Began dosing of TC-210 in the Phase 1/2 trial for patients with mesothelin-expressing solid tumors and an interim update anticipated in 4Q19/1Q20 • Leading clinical sites participating in the TC-210 trial include Sarah Cannon Research Institute, MD Anderson Cancer Center and the National Cancer Institute • IND filing for TC-110 in patients with CD19+ non-Hodgkin lymphoma or adult acute lymphoblastic leukemia anticipated in 2H19 CAMBRIDGE, Mass.

TCR2 Therapeutics Reports First Quarter 2019 Financial Results and Provides Corporate Update

TCR2 Therapeutics Reports First Quarter 2019 Financial Results and Provides Corporate Update • Initiated Phase 1/2 clinical trial for TC-210, TCR2’s lead product candidate targeting mesothelin expressing solid tumors • On track to file an IND for TCR2’s lead hematology product candidate, TC-110, in patients with CD19+ non-Hodgkin lymphomas and leukemias in 2H 2019 • Recent publication in Nature Communications and scientific presentations highlight advantages of the Company’s TRuCTM-T cell platform • Established occupancy of manufacturing suite at Cell and Gene Therapy Catapult in the UK CAMBRIDGE, Mass.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): May 13, 2019 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fil

May 13, 2019

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-Q x QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2019 OR o 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 001-38811 TCR2 Therapeutics Inc.

Amendment #1 to 2018 Stock Option and Incentive Plan

TCR2 THERAPEUTICS INC. AMENDMENT NO. 1 TO 2018 STOCK OPTION AND INCENTIVE PLAN The TCR2 Therapeutics Inc. 2018 Stock Option and Incentive Plan (the “Plan”) is hereby amended by the Board of Directors as follows: Section 3(a) of the Plan is hereby amended restated to read in its entirety as follows: SECTION 3. STOCK ISSUABLE UNDER THE PLAN; MERGERS; SUBSTITUTION (a) Stock Issuable. The maximum numb

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): April 1, 2019 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commission Fi

TCR2 Therapeutics Reports Fourth Quarter and Full Year 2018 Financial Results and Provides Corporate Update

TCR2 Therapeutics Reports Fourth Quarter and Full Year 2018 Financial Results and Provides Corporate Update • U.

Form 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, DC 20549 FORM 10-K x 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 o 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 001-38811 TCR2 Therapeutics Inc.

Joint Filing Statement

EX-99.C Exhibit C Joint Filing Statement I, the undersigned, hereby express my agreement that the attached Schedule 13D (and any amendments thereto) relating to the beneficial ownership by the undersigned of the equity securities of TCR2 Therapeutics Inc. is filed on behalf of each of the undersigned. Date: March 4, 2019 MPM BIOVENTURES 2014, L.P. By: MPM BioVentures 2014 GP LLC, its General Partn

TCRR / TCR2 THERAPEUTICS INC. / Mpm Bioventures 2014, L.p. - SC 13D Activist Investment

SC 13D UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 13D UNDER THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. )* TCR2 Therapeutics Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 87808K106 (CUSIP Number) Luke Evnin MPM Asset Management 450 Kendall Street Cambridge, MA 01242 Telephone: (617) 425-9200 (Name, Address and Telephone Number of Per

TCR2 Therapeutics Announces Exercise of Over-Allotment Option

EX-99.1 Exhibit 99.1 FOR IMMEDIATE RELEASE TCR2 Therapeutics Announces Exercise of Over-Allotment Option Cambridge, Mass., February 26, 2019 – TCR2 Therapeutics Inc. (Nasdaq: TCRR), a clinical-stage immunotherapy company developing the next generation of novel T cell receptor (TCR) therapies for patients suffering from cancer, today announced that the underwriters of its recent initial public offe

Financial Statements and Exhibits, Other Events

8-K 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): February 26, 2019 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (Commi

Amendments to Articles of Incorporation or Bylaws; Change in Fiscal Year, Financial Statements and Exhibits

Form 8-K 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): February 19, 2019 TCR2 THERAPEUTICS INC. (Exact name of registrant as specified in its charter) Delaware 001-38811 47-4152751 (State or other jurisdiction of incorporation) (

Amended and Restated By-laws of the Registrant

EX-3.2 Exhibit 3.2 AMENDED AND RESTATED BY-LAWS OF TCR2 THERAPEUTICS INC. (the “Corporation”) ARTICLE I Stockholders SECTION 1. Annual Meeting. The annual meeting of stockholders (any such meeting being referred to in these By-laws as an “Annual Meeting”) shall be held at the hour, date and place within or without the United States which is fixed by the Board of Directors, which time, date and pla

Amended and Restated Certificate of Incorporation of the Registrant

EX-3.1 Exhibit 3.1 THIRD AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF TCR2 THERAPEUTICS INC. TCR2 Therapeutics Inc., a corporation organized and existing under the laws of the State of Delaware (the “Corporation”), hereby certifies as follows: 1. The name of the Corporation is TCR2 Therapeutics Inc. The date of the filing of its original Certificate of Incorporation with the Secretary of S

TCRR / TCR2 THERAPEUTICS INC. / Upnorth Investment Ltd - SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* TCR2 Therapeutics Inc. (Name of Issuer) Common stock, par value US$0.0001 per share (Title of Class of Securities) 87808K106 (CUSIP Number) February 13, 2019 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate th

JOINT FILING AGREEMENT

Exhibit 99.1 JOINT FILING AGREEMENT In accordance with Rule 13d-1(k) promulgated under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree to the joint filing with all other Reporting Persons (as such term is defined in the Schedule 13G referred to below) on behalf of each of them of a statement on Schedule 13G (including amendments thereto) with respect to the Common Sto

Joint Filing Agreement

Exhibit 99.1 Joint Filing Agreement In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended (the “Exchange Act”), the undersigned hereby agree to the joint filing on behalf of each of them of a Statement on Schedule 13G (including any and all amendments thereto, the “Schedule 13G”) relating to the Common Stock, $0.0001 par value per share, of TCR2 Therapeutics Inc

TCRR / TCR2 THERAPEUTICS INC. / Redmile Group, LLC - SCHEDULE 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. ) TCR2 Therapeutics Inc. (Name of Issuer) Common Stock, $0.0001 par value (Title of Class of Securities) 87808K106 (CUSIP Number) February 19, 2019 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursua