TSVT.V / 2seventy bio Inc - Pengajuan SECLaporan Tahunan, Pernyataan Proksi

2seventy bio Inc
US ˙ NASDAQ
HINDI NA ACTIVE ANG SIMBONG ITO

Mga Batayang Estadistika
CIK 1860782
SEC Filings
All companies that sell securities in the United States must register with the Securities and Exchange Commission (SEC) and file reports on a regular basis. These reports include company annual reports (10K, 10Q), news updates (8K), investor presentations (found in 8Ks), insider trades (form 4), ownership reports (13D, and 13G), and reports related to the specific securities sold, such as registration statements and prospectus. This page shows recent SEC filings related to 2seventy bio Inc
SEC Filings (Chronological Order)
Halaman ini menyediakan daftar lengkap dan kronologis dari Pengajuan SEC, tidak termasuk pengajuan kepemilikan yang kami sediakan di tempat lain.
May 23, 2025 15-12G

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 Number: 001-40791 2seventy bio, Inc. (Exact name of registrant as specified in its

May 13, 2025 S-8 POS

As filed with the Securities and Exchange Commission on May 13, 2025

As filed with the Securities and Exchange Commission on May 13, 2025 Registration No.

May 13, 2025 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): May 13, 2025 2seventy bio, 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): May 13, 2025 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File Nu

May 13, 2025 EX-3.1

SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION 2SEVENTY BIO, INC. ARTICLE ONE

Exhibit 3.1 SECOND AMENDED AND RESTATED CERTIFICATE OF INCORPORATION OF 2SEVENTY BIO, INC. ARTICLE ONE The name of the corporation is 2seventy bio, Inc. (hereinafter called the “Corporation”). ARTICLE TWO The address of the Corporation’s registered office in the State of Delaware is 1209 Orange Street, New Castle County, Wilmington, Delaware 19801. The name of its registered agent at such address

May 13, 2025 SC 14D9/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No. 4) 2seventy bio, Inc. (Name of Su

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No. 4) 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Persons Filing Statement) Common Stock, par value $0.0001 per share (Title of Class of Securities) 90138410

May 13, 2025 S-8 POS

As filed with the Securities and Exchange Commission on May 13, 2025

As filed with the Securities and Exchange Commission on May 13, 2025 Registration No.

May 13, 2025 EX-3.2

SECOND AMENDED AND RESTATED BYLAWS 2SEVENTY BIO, INC. A Delaware Corporation ARTICLE I

Exhibit 3.2 SECOND AMENDED AND RESTATED BYLAWS OF 2SEVENTY BIO, INC. A Delaware Corporation ARTICLE I OFFICES Section 1.1 Registered Office. The registered office of the corporation in the State of Delaware shall be located at Corporation Trust Center, 1209 Orange Street, New Castle County, Wilmington, Delaware 19801. The name of the corporation’s registered agent at such address shall be The Corp

May 13, 2025 S-8 POS

As filed with the Securities and Exchange Commission on May 13, 2025

As filed with the Securities and Exchange Commission on May 13, 2025 Registration No.

May 13, 2025 S-8 POS

As filed with the Securities and Exchange Commission on May 13, 2025

As filed with the Securities and Exchange Commission on May 13, 2025 Registration No.

May 13, 2025 POS AM

As filed with the Securities and Exchange Commission on May 13, 2025

As filed with the Securities and Exchange Commission on May 13, 2025 Registration No.

May 13, 2025 SC TO-T/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 5) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 5) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER SUB INC. (Offeror) A Wholly Owned Subsidiary of BRISTOL-MYERS SQUIBB COMPANY (Parent of Offeror) (Names of Filing Persons (identify

May 7, 2025 8-K

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 7, 2025 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File Num

May 7, 2025 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2025 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 001-40791 2seventy bio, Inc. (E

May 7, 2025 EX-99.1

2seventy bio Reports First Quarter Financial Results and Provides Update on Proposed Acquisition by Bristol Myers Squibb Acquisition by Bristol Myers Squibb on track to close in the second quarter of 2025: HSR waiting period expired on May 2, 2025; t

2seventy bio Reports First Quarter Financial Results and Provides Update on Proposed Acquisition by Bristol Myers Squibb Acquisition by Bristol Myers Squibb on track to close in the second quarter of 2025: HSR waiting period expired on May 2, 2025; tender offer expected to expire on May 13, 2025 Abecma generated $59 million U.

May 6, 2025 SC TO-T/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 4) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 4) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER SUB INC. (Offeror) A Wholly Owned Subsidiary of BRISTOL-MYERS SQUIBB COMPANY (Parent of Offeror) (Names of Filing Persons (identify

May 5, 2025 SC 14D9/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No. 3) 2seventy bio, Inc. (Name of Su

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No. 3) 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Persons Filing Statement) Common Stock, par value $0.0001 per share (Title of Class of Securities) 90138410

May 5, 2025 SC TO-T/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 3) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 3) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER SUB INC. (Offeror) A Wholly Owned Subsidiary of BRISTOL-MYERS SQUIBB COMPANY (Parent of Offeror) (Names of Filing Persons (identify

April 28, 2025 10-K/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For transition period from to Commission File Number 001-40791 2seventy bio, Inc

April 23, 2025 SC 14D9/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No. 2) 2seventy bio, Inc. (Name of Su

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No. 2) 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Persons Filing Statement) Common Stock, par value $0.0001 per share (Title of Class of Securities) 90138410

April 23, 2025 SC TO-T/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 2) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 2) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER SUB INC. (Offeror) A Wholly Owned Subsidiary of BRISTOL-MYERS SQUIBB COMPANY (Parent of Offeror) (Names of Filing Persons (identify

April 17, 2025 SC TO-T/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER SUB INC. (Offeror) A Wholly Owned Subsidiary of BRISTOL-MYERS SQUIBB COMPANY (Parent of Offeror) (Names of Filing Persons (identify

April 17, 2025 SC 14D9/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No. 1) 2seventy bio, Inc. (Name of Su

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 (Amendment No. 1) 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Persons Filing Statement) Common Stock, par value $0.0001 per share (Title of Class of Securities) 90138410

April 14, 2025 EX-99.(A)(1)(I)

Offer to Purchase for Cash All Outstanding Shares of Common Stock 2SEVENTY BIO, INC. $5.00 Net Per Share DAYBREAK MERGER SUB INC. a wholly owned subsidiary of BRISTOL-MYERS SQUIBB COMPANY THE OFFER AND WITHDRAWAL RIGHTS EXPIRE ONE MINUTE FOLLOWING 11

TABLE OF CONTENTS Exhibit (a)(1)(i) Offer to Purchase for Cash All Outstanding Shares of Common Stock of 2SEVENTY BIO, INC.

April 14, 2025 EX-99.(D)(2)

TENDER AND SUPPORT AGREEMENT

Exhibit (d)(2) TENDER AND SUPPORT AGREEMENT This Tender and Support Agreement (this “Agreement”), dated as of March 10, 2025, is entered into by and between Bristol-Myers Squibb Company, a Delaware corporation (“Parent”), and the undersigned stockholder of 2seventy bio, Inc.

April 14, 2025 EX-99.(A)(1)(V)

NOTICE OF GUARANTEED DELIVERY to Tender Shares of Common Stock 2SEVENTY BIO, INC. $5.00 Net Per Share Pursuant to the Offer to Purchase Dated April 14, 2025 DAYBREAK MERGER SUB INC. a wholly owned subsidiary of Bristol-Myers Squibb Company

Exhibit (a)(1)(v) NOTICE OF GUARANTEED DELIVERY to Tender Shares of Common Stock of 2SEVENTY BIO, INC.

April 14, 2025 EX-99.(A)(1)(II)

Letter of Transmittal to Tender Shares of Common Stock 2SEVENTY BIO, INC. At $5.00 Net per Share Pursuant to the Offer to Purchase Dated April 14, 2025 by Daybreak Merger Sub Inc. a wholly owned subsidiary of Bristol-Myers Squibb Company

Exhibit (a)(1)(ii) Letter of Transmittal to Tender Shares of Common Stock of 2SEVENTY BIO, INC.

April 14, 2025 SC TO-T

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER SUB INC. (Offeror) A Wholly Owned Subsidiary of BRISTOL-MYERS SQUIBB COMPANY (Parent of Offeror) (Names of Filing Persons (identifying status as offe

April 14, 2025 SC 14D9

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 2seventy bio, Inc. (Name of Subject Company) 2se

TABLE OF CONTENTS UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) Solicitation/Recommendation Statement Under Section 14(d)(4) of the Securities Exchange Act of 1934 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Persons Filing Statement) Common Stock, par value $0.0001 per share (Title of Class of Securities)   901384

April 14, 2025 EX-99.(A)(1)(VI)

Notice of Offer to Purchase for Cash All Outstanding Shares of Common Stock 2SEVENTY BIO, INC. $5.00 Net Per Share DAYBREAK MERGER SUB INC. a wholly owned subsidiary of BRISTOL-MYERS SQUIBB COMPANY

Exhibit (a)(1)(vi) This announcement is neither an offer to purchase nor a solicitation of an offer to sell Shares (as defined below).

April 14, 2025 EX-FILING FEES

Calculation of Filing Fee Tables Schedule TO-T (Rule 14d-100) 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER SUB INC. a wholly owned subsidiary of BRISTOL-MYERS SQUIBB COMPANY (Names of Filing Persons (Offerors))

Exhibit 107 Calculation of Filing Fee Tables Schedule TO-T (Rule 14d-100) 2SEVENTY BIO, INC.

April 14, 2025 EX-99.(A)(1)(IV)

Offer to Purchase for Cash All Outstanding Shares of Common Stock 2SEVENTY BIO, INC. $5.00 Net Per Share Pursuant to the Offer to Purchase Dated April 14, 2025 DAYBREAK MERGER SUB INC. a wholly owned subsidiary of Bristol-Myers Squibb Company

Exhibit (a)(1)(iv) Offer to Purchase for Cash All Outstanding Shares of Common Stock of 2SEVENTY BIO, INC.

April 14, 2025 EX-99.(A)(1)(III)

Offer to Purchase for Cash All Outstanding Shares of Common Stock 2SEVENTY BIO, INC. $5.00 Net Per Share Pursuant to the Offer to Purchase Dated April 14, 2025 DAYBREAK MERGER SUB INC. a wholly owned subsidiary of Bristol-Myers Squibb Company

Exhibit (a)(1)(iii) Offer to Purchase for Cash All Outstanding Shares of Common Stock of 2SEVENTY BIO, INC.

March 25, 2025 EX-10.27

Executive Employment Agreement between 2seventy bio, Inc. and Jessica Snow, dated as of January 6, 2025 (incorporated by reference to Exhibit 10.27 to Annual Report on Form 10-K filed on March 25, 2025).

Exhibit 10.27 EMPLOYMENT AGREEMENT This Employment Agreement (“Agreement”) by and between 2seventy bio, Inc., a Delaware corporation (the “Company”), and Jessica Snow (the “Executive”) is effective as of January 6, 2025 (the “Effective Date”). This Agreement supersedes in all respects all prior and contemporaneous agreements, representations and communications between the Executive and the Company

March 25, 2025 8-K

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 25, 2025 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

March 25, 2025 EX-99.1

2seventy bio Reports Fourth Quarter and Full Year 2024 Financial Results Entered into definitive merger agreement to be acquired by Bristol Myers Squibb at a price of $5.00 per share in an all-cash transaction; expected to close in the second quarter

2seventy bio Reports Fourth Quarter and Full Year 2024 Financial Results Entered into definitive merger agreement to be acquired by Bristol Myers Squibb at a price of $5.

March 25, 2025 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2024 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For transition period from to Commission File Number 001-40791 2seventy bio, Inc.

March 25, 2025 EX-10.26

Executive Employment Agreement between 2seventy bio, Inc. and Victoria Eatwell, dated as of January

Exhibit 10.26 EMPLOYMENT AGREEMENT This Employment Agreement (“Agreement”) by and between 2seventy bio, Inc., a Delaware corporation (the “Company”), and Victoria Eatwell (the “Executive”) is effective as of January 6, 2025 (the “Effective Date”). This Agreement supersedes in all respects all prior and contemporaneous agreements, representations and communications between the Executive and the Com

March 25, 2025 EX-10.25

Executive Employment Agreement between 2seventy bio, Inc. and William Baird, dated as of January

Exhibit 10.25 EMPLOYMENT AGREEMENT This Employment Agreement (“Agreement”) by and between 2seventy bio, Inc., a Delaware corporation (the “Company”), and William Baird (the “Executive”) is effective as of January 6, 2025 (the “Effective Date”). This Agreement supersedes in all respects all prior and contemporaneous agreements, representations and communications between the Executive and the Compan

March 17, 2025 NT 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 12b-25 NOTIFICATION OF LATE FILING

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 12b-25 NOTIFICATION OF LATE FILING (Check One): ☒ Form 10-K ☐ Form 20-F ☐ Form 11-K ☐ Form 10-Q ☐ Form 10-D ☐ Form N-CEN ☐ Form N-CSR For Period Ended: December 31, 2024 ☐ Transition Report on Form 10-K ☐ Transition Report on Form 20-F ☐ Transition Report on Form 11-K ☐ Transition Report on Form 10-Q For the Transition Pe

March 14, 2025 SC14D9C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) SOLICITATION/RECOMMENDATION STATEMENT UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934 2seventy bio, Inc. (Name of Subject Company) 2se

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) SOLICITATION/RECOMMENDATION STATEMENT UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Person(s) Filing Statement) COMMON STOCK, PAR VALUE $0.0001 PER SHARE (Title of Class of Securities) 901384107 (CUSIP Number

March 14, 2025 EX-99.1B

Cautionary Note Regarding Forward-Looking Statements

Exhibit 99.1 Cautionary Note Regarding Forward-Looking Statements This document contains statements that are not statements of historical fact, or “forward-looking statements”, including with respect to the proposed acquisition of 2seventy bio by BMS, the expected timetable for completing the transaction, future opportunities for the combined businesses, the expected benefits of BMS’s acquisition

March 13, 2025 EX-99.1

-BMS CONFIDENTIAL-

Exhibit 99.1 -BMS CONFIDENTIAL- From: Lynelle Hoch To: 2seventy bio employees Date: Thursday, 3/13 Subject: Continuing our work together to bring Abecma to patients Dear 2seventy bio colleagues, Monday was an important day with the announcement that Bristol Myers Squibb (BMS) has entered into an agreement to acquire 2seventy bio. As the president of BMS’ Cell Therapy Organization, I have had a fro

March 13, 2025 SC TO-C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE TO TENDER OFFER STATEMENT UNDER SECTION 14(d)(1) OR 13(e)(1) OF THE SECURITIES EXCHANGE ACT OF 1934 2SEVENTY BIO, INC. (Name of Subject Company (Issuer)) DAYBREAK MERGER SUB INC. (Offeror) A Wholly Owned Subsidiary of BRISTOL-MYERS SQUIBB COMPANY (Offeror) (Name of Filing Persons (identifying status as offeror, issuer

March 13, 2025 SC14D9C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) SOLICITATION/RECOMMENDATION STATEMENT UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934 2seventy bio, Inc. (Name of Subject Company) 2se

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) SOLICITATION/RECOMMENDATION STATEMENT UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Person(s) Filing Statement) COMMON STOCK, PAR VALUE $0.0001 PER SHARE (Title of Class of Securities) 901384107 (CUSIP Number

March 13, 2025 EX-99.1

-BMS CONFIDENTIAL-

Exhibit 99.1 -BMS CONFIDENTIAL- From: Lynelle Hoch To: 2seventy bio employees Date: Thursday, 3/13 Subject: Continuing our work together to bring Abecma to patients Dear 2seventy bio colleagues, Monday was an important day with the announcement that Bristol Myers Squibb (BMS) has entered into an agreement to acquire 2seventy bio. As the president of BMS’ Cell Therapy Organization, I have had a fro

March 11, 2025 EX-99.1

2seventy bio Enters into Definitive Agreement to be Acquired by Bristol Myers Squibb $5.00 per share, all-cash transaction Expected to close in the second quarter of 2025, subject to customary closing conditions

Exhibit 99.1 2seventy bio Enters into Definitive Agreement to be Acquired by Bristol Myers Squibb $5.00 per share, all-cash transaction Expected to close in the second quarter of 2025, subject to customary closing conditions CAMBRIDGE, Mass.— (BUSINESS WIRE)—March 10, 2025—2seventy bio, Inc. (Nasdaq: TSVT), today announced a definitive merger agreement under which Bristol Myers Squibb (NYSE: BMY)

March 11, 2025 EX-2.1

Agreement and Plan of Merger, dated as of March 10, 2025 by and among Bristol-Myers Squibb Company, Daybreak Merger Sub Inc. and 2seventy bio, Inc.

Exhibit 2.1 Execution version AGREEMENT AND PLAN OF MERGER BY AND AMONG BRISTOL-MYERS SQUIBB COMPANY, DAYBREAK MERGER SUB INC. and 2SEVENTY BIO, INC. Dated as of March 10, 2025 TABLE OF CONTENTS ARTICLE 1 DEFINITIONS 2 Section 1.1. Definitions 2 ARTICLE 2 THE OFFER 15 Section 2.1. Tender Offer 15 Section 2.2. Actions of Parent and Merger Sub 18 Section 2.3. Actions of the Company 19 ARTICLE 3 THE

March 11, 2025 EX-99.2

Cautionary Note Regarding Forward-Looking Statements

Exhibit 99.2 Cautionary Note Regarding Forward-Looking Statements This document contains statements that are not statements of historical fact, or “forward-looking statements”, including with respect to the proposed acquisition of 2seventy bio by BMS, the expected timetable for completing the transaction, future opportunities for the combined businesses, the expected benefits of BMS’s acquisition

March 11, 2025 EX-99.1

Exciting News and Townhall Tomorrow

Exhibit 99.1 Subject: Exciting News and Townhall Tomorrow Dear Team 2seventy, Exciting news this evening - we have reached an agreement to be acquired by BMS for $5.00 per share in an all-cash transaction. This proposed acquisition is consistent with our focus on unlocking the value of Abecma with the goal of delivering more time for people living with multiple myeloma and maximizing value for all

March 11, 2025 SC14D9C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) SOLICITATION/RECOMMENDATION STATEMENT UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934 2seventy bio, Inc. (Name of Subject Company) 2se

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) SOLICITATION/RECOMMENDATION STATEMENT UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Person(s) Filing Statement) COMMON STOCK, PAR VALUE $0.0001 PER SHARE (Title of Class of Securities) 901384107 (CUSIP Number

March 11, 2025 SC14D9C

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) SOLICITATION/RECOMMENDATION STATEMENT UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934 2seventy bio, Inc. (Name of Subject Company) 2se

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14D-9 (Rule 14d-101) SOLICITATION/RECOMMENDATION STATEMENT UNDER SECTION 14(d)(4) OF THE SECURITIES EXCHANGE ACT OF 1934 2seventy bio, Inc. (Name of Subject Company) 2seventy bio, Inc. (Name of Person(s) Filing Statement) COMMON STOCK, PAR VALUE $0.0001 PER SHARE (Title of Class of Securities) 901384107 (CUSIP Number

March 11, 2025 8-K

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): March 10, 2025 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

February 6, 2025 8-K

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): February 6, 2025 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission Fil

February 6, 2025 EX-99.1

2seventy bio Reports Preliminary* Full-Year U.S. Abecma Sales and Select Financial Results $242 million in U.S. Abecma sales in 2024 Approximately $184 million of cash, cash equivalents and marketable securities as of December 31, 2024 Net cash burn

2seventy bio Reports Preliminary* Full-Year U.S. Abecma Sales and Select Financial Results $242 million in U.S. Abecma sales in 2024 Approximately $184 million of cash, cash equivalents and marketable securities as of December 31, 2024 Net cash burn of $9 million in the fourth quarter of 2024; path to quarterly breakeven by the end of 2025 CAMBRIDGE, Mass - [BUSINESS WIRE] - February 6, 2025 - 2se

January 10, 2025 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

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 6, 2025 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

November 12, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2024 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 001-40791 2seventy bio, Inc

November 12, 2024 EX-99.2

Unleash Time 2seventy bio company presentation November 2024 2 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”. These statements include, but are not li

Unleash Time 2seventy bio company presentation November 2024 2 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”.

November 12, 2024 EX-99.1

2seventy bio Reports Third Quarter Financial Results and Recent Operational Progress Abecma generated $77 million U.S. commercial revenue, growing 42% versus the second quarter Decision in September to discontinue enrollment in KarMMa-9 study results

2seventy bio Reports Third Quarter Financial Results and Recent Operational Progress Abecma generated $77 million U.

November 12, 2024 8-K

Regulation FD Disclosure, 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, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission Fi

October 31, 2024 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): October 31, 2024 2seventy bio, 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): October 31, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission Fil

September 25, 2024 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): September 25, 2024 2seventy bio,

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): September 25, 2024 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission F

September 25, 2024 EX-99.2

Unleash Time 2seventy bio company presentation September 2024 2 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”. These statements include, but are not l

a2seventysept2024corpora Unleash Time 2seventy bio company presentation September 2024 2 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”.

September 25, 2024 EX-99.1

2seventy bio Provides Update on KarMMa-9 Study and Previews Anticipated Strong Third Quarter Revenue Performance 2seventy and Bristol Myers Squibb discontinue enrollment in Phase 3 KarMMa-9 study Decision results in over $80 million in anticipated co

2seventy bio Provides Update on KarMMa-9 Study and Previews Anticipated Strong Third Quarter Revenue Performance 2seventy and Bristol Myers Squibb discontinue enrollment in Phase 3 KarMMa-9 study Decision results in over $80 million in anticipated cost savings for 2seventy over the next several years and accelerates path to breakeven in 2025 Expanded 3L+ label drives re-acceleration in Abecma U.

August 8, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2024 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 001-40791 2seventy bio, Inc. (Ex

August 8, 2024 EX-10.1

Asset Purchase Agreement between 2seventy bio, Inc. and Novo Nordisk A/S, dated as of June 21, 2024.

Exhibit 10.1 Certain information indicated with [***] in this document has been omitted from this exhibit because it is both (i) not material and (ii) would be competitively harmful if publicly disclosed. ASSET PURCHASE AGREEMENT BY AND BETWEEN 2SEVENTY BIO, INC. AND NOVO NORDISK A/S DATED AS OF JUNE 21, 2024 TABLE OF CONTENTS ARTICLE 1. DEFINITIONS 1 1.1 Definitions 1 ARTICLE 2. PURCHASE AND SALE

August 7, 2024 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): August 7, 2024 2seventy bio, 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): August 7, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

August 7, 2024 EX-99.1

2seventy bio Reports Second Quarter Financial Results and Recent Operational Progress Following regulatory approval in the earlier line setting this quarter, Abecma generated $54 million U.S. commercial revenue and saw meaningful growth in demand Rec

2seventy bio Reports Second Quarter Financial Results and Recent Operational Progress Following regulatory approval in the earlier line setting this quarter, Abecma generated $54 million U.

July 26, 2024 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, 2024 2seventy bio, 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): July 26, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File N

June 26, 2024 EX-99.1

2seventy bio Announces Sale of Hemophilia A Candidate and MegaTAL In Vivo Gene Editing Technology to Novo Nordisk for up to $40 million - Divestiture Supports Company Focus on Development and Commercialization of Abecma -

2seventy bio Announces Sale of Hemophilia A Candidate and MegaTAL In Vivo Gene Editing Technology to Novo Nordisk for up to $40 million - Divestiture Supports Company Focus on Development and Commercialization of Abecma - CAMBRIDGE, Mass.

June 26, 2024 8-K

Regulation FD Disclosure, Entry into a Material Definitive Agreement, Financial Statements and Exhibits, Costs Associated with Exit or Disposal Activities, 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 21, 2024 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File N

June 11, 2024 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): June 10, 2024 2seventy bio, 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): June 10, 2024 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File N

June 11, 2024 EX-99.1

Unleash Time2seventy bio company presentation May 2024 2 Cautionary note regarding forward-looking statements strategies, timelines and expectations with respect to the development and commercialization of Abecma Abecma; the progress and results of o

a2seventyapril2024irpres Unleash Time2seventy bio company presentation May 2024 2 Cautionary note regarding forward-looking statements strategies, timelines and expectations with respect to the development and commercialization of Abecma Abecma; the progress and results of our commercialization of Abecma, including our goal of increasing manufacturing capacity and improving the manufacturing proce

May 9, 2024 EX-10.1

Asset Purchase Agreement between 2seventy bio, Inc. and Regeneron Pharmaceuticals, Inc., dated as of January 29, 2024.

Exhibit 10.1 Certain information indicated with [***] in this document has been omitted from this exhibit because it is both (i) not material and (ii) would be competitively harmful if publicly disclosed. ASSET PURCHASE AGREEMENT BY AND BETWEEN 2SEVENTY BIO, INC. AND REGENERON PHARMACEUTICALS, INC. DATED AS OF January 29, 2024 TABLE OF CONTENTS Page EXHIBITS AND SCHEDULES Exhibit A Assignment and

May 9, 2024 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 2024 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 001-40791 2seventy bio, Inc. (E

May 8, 2024 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): May 8, 2024 2seventy bio, Inc. (E

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 8, 2024 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File Num

May 8, 2024 EX-99.1

2seventy bio Reports First Quarter Financial Results and Recent Operational Progress U.S. FDA Approval of Abecma for Triple-Class Exposed Relapsed or Refractory Multiple Myeloma After Two Prior Lines of Therapy; Commercial Launch Underway Completion

2seventy bio Reports First Quarter Financial Results and Recent Operational Progress U.

April 25, 2024 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): April 25, 2024 2seventy bio, 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): April 25, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

April 25, 2024 DEFA14A

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

April 25, 2024 DEF 14A

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 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)

April 9, 2024 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): April 9, 2024 2seventy bio, 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): April 9, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File N

April 5, 2024 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): April 5, 2024 2seventy bio, 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): April 5, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File N

April 5, 2024 EX-99.1

U.S. FDA Approves Bristol Myers Squibb and 2seventy bio’s Abecma for Triple-Class Exposed Relapsed or Refractory Multiple Myeloma After Two Prior Lines of Therapy Abecma tripled progression-free survival compared to standard regimens in the Phase 3 K

U.S. FDA Approves Bristol Myers Squibb and 2seventy bio’s Abecma for Triple-Class Exposed Relapsed or Refractory Multiple Myeloma After Two Prior Lines of Therapy Abecma tripled progression-free survival compared to standard regimens in the Phase 3 KarMMa-3 trial, with a 51% reduction in risk of disease progression or death and a well-established safety profile Expanded approval brings this person

April 1, 2024 EX-10.1

Amended and Restated Transitional Services Agreement between 2seventy bio, Inc. and Nick Leschly, dated as of March 29, 2024

Exhibit 10.1 March 29, 2024 Nick Leschly Re: Amended and Restated Transitional Services Agreement Dear Nick: This letter (the “Agreement”) follows our conversations regarding your employment with 2seventy bio, Inc. (the “Company”). This confirms that you will be transitioning from your CEO position in connection with, and conditioned on the closing of, the transactions contemplated by the Asset Pu

April 1, 2024 EX-99.2

2seventy bio Announces Completion of Oncology and Autoimmune Pipeline Divestiture to Regeneron - Company Now Exclusively Focused on Development and Commercialization of Abecma -

Exhibit 99.2 2seventy bio Announces Completion of Oncology and Autoimmune Pipeline Divestiture to Regeneron - Company Now Exclusively Focused on Development and Commercialization of Abecma - CAMBRIDGE, Mass. — (BUSINESS WIRE)— April 1, 2024 —2seventy bio, Inc. (Nasdaq: TSVT), announced today the completion of the asset purchase agreement (“APA”) by Regeneron Pharmaceuticals, Inc. Under the terms o

April 1, 2024 EX-99.2

2seventy bio Announces Completion of Oncology and Autoimmune Pipeline Divestiture to Regeneron - Company Now Exclusively Focused on Development and Commercialization of Abecma -

Exhibit 99.2 2seventy bio Announces Completion of Oncology and Autoimmune Pipeline Divestiture to Regeneron - Company Now Exclusively Focused on Development and Commercialization of Abecma - CAMBRIDGE, Mass. — (BUSINESS WIRE)— April 1, 2024 —2seventy bio, Inc. (Nasdaq: TSVT), announced today the completion of the asset purchase agreement (“APA”) by Regeneron Pharmaceuticals, Inc. Under the terms o

April 1, 2024 8-K/A

Financial Statements and Exhibits

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) 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 29, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporatio

April 1, 2024 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): March 29, 2024 2seventy bio, 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 29, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

April 1, 2024 EX-10.1

Amended and Restated Transitional Services Agreement between 2seventy bio, Inc. and Nick Leschly, dated as of March 29, 2024.

Exhibit 10.1 March 29, 2024 Nick Leschly Re: Amended and Restated Transitional Services Agreement Dear Nick: This letter (the “Agreement”) follows our conversations regarding your employment with 2seventy bio, Inc. (the “Company”). This confirms that you will be transitioning from your CEO position in connection with, and conditioned on the closing of, the transactions contemplated by the Asset Pu

April 1, 2024 EX-99.1

UNAUDITED PRO FORMA FINANCIAL INFORMATION

Exhibit 99.1 UNAUDITED PRO FORMA FINANCIAL INFORMATION On April 1, 2024 (the “Closing Date”), 2seventy bio, Inc. (“2seventy”, the “Company” “we” or “us”) completed the previously announced transaction (the “Transaction”), pursuant to which the Company has agreed to sell to Regeneron Pharmaceuticals, Inc. (“Regeneron”) the Company’s oncology and autoimmune research and development programs, clinica

April 1, 2024 EX-99.1

UNAUDITED PRO FORMA CONDENSED CONSOLIDATED FINANCIAL INFORMATION

Exhibit 99.1 UNAUDITED PRO FORMA CONDENSED CONSOLIDATED FINANCIAL INFORMATION On April 1, 2024 (the “Closing Date”), 2seventy bio, Inc. (“2seventy”, the “Company” “we” or “us”) completed the previously announced transaction (the “Transaction”), pursuant to which the Company has agreed to sell to Regeneron Pharmaceuticals, Inc. (“Regeneron”) the Company’s oncology and autoimmune research and develo

March 20, 2024 EX-99.1

2seventy bio Announces Appointments of Eli Casdin and Charles Newton to Board of Directors

2seventy bio Announces Appointments of Eli Casdin and Charles Newton to Board of Directors CAMBRIDGE, Mass.

March 20, 2024 EX-99.1

Press release issued by 2seventy bio, Inc. on March 20, 2024

2seventy bio Announces Appointments of Eli Casdin and Charles Newton to Board of Directors CAMBRIDGE, Mass.

March 20, 2024 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): March 20, 2024 2seventy bio, 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 20, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

March 20, 2024 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

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 Proxy Statement

March 18, 2024 EX-10.1

Release and Equity Agreement, by and between 2seventy bio, Inc. and Philip Gregory

March 11, 2024 Philip Gregory Re: Release and Equity Agreement Dear Philip: As you know, 2seventy bio, Inc.

March 18, 2024 EX-99.1

FDA Advisory Committee Votes in Favor of Bristol Myers Squibb’s and 2seventy bio’s Abecma for Triple-Class Exposed Multiple Myeloma in Earlier Lines of Therapy The supplemental Biologics License Application for Abecma in this indication remains under

FDA Advisory Committee Votes in Favor of Bristol Myers Squibb’s and 2seventy bio’s Abecma for Triple-Class Exposed Multiple Myeloma in Earlier Lines of Therapy The supplemental Biologics License Application for Abecma in this indication remains under review with the FDA; Abecma has been approved in Japan and Switzerland and received a positive CHMP Opinion by the European Medicines Agency based on KarMMa-3 (PRINCETON, N.

March 18, 2024 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): March 13, 2024 2seventy bio, 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 13, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

March 13, 2024 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): March 12, 2024 2seventy bio, 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 12, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

March 7, 2024 EX-19.1

Insider Trading Policy.

INSIDER TRADING POLICY PURPOSE The policy of 2seventy bio, Inc. (the “Company”) is that it will comply with all applicable laws and regulations in conducting its business. Each employee and each officer and director of the Company is expected to abide by this policy. This “Insider Trading Policy” covers the trading in the Company’s securities and the disclosure and use of information concerning th

March 7, 2024 EX-97.1

ompensation Recovery Policy, effective as of

2SEVENTY BIO, INC. COMPENSATION RECOVERY POLICY Adopted as of September 26, 2023 2seventy bio, Inc., a Delaware corporation (the “Company”), has adopted a Compensation Recovery Policy (this “Policy”) as described below. This Policy supersedes and replaces the Company’s Policy for Recoupment of Incentive Compensation, dated as of September , 2021 (the “Prior Policy”) with respect to Incentive Compe

March 7, 2024 EX-10.14

Amendment to License Agreement, dated January 16, 2024, by and between 2seventy bio, Inc. and the Nat

Certain information indicated with [***] in this document has been omitted from this exhibit because it is both (i) not material and (ii) would be competitively harmful if publicly disclosed.

March 7, 2024 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For transition period from to Commission File Number 001-40791 2seventy bio, Inc.

March 5, 2024 EX-99.1

2seventy bio Reports Fourth Quarter and Full Year 2023 Financial Results and Recent Operational Progress New strategic path forward as Abecma-focused company announced in January 2024; on track to close Asset Sale of R&D pipeline to Regeneron in the

2seventy bio Reports Fourth Quarter and Full Year 2023 Financial Results and Recent Operational Progress New strategic path forward as Abecma-focused company announced in January 2024; on track to close Asset Sale of R&D pipeline to Regeneron in the first half of 2024 U.

March 5, 2024 8-K

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 5, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File N

February 14, 2024 SC 13G/A

MX:TSVT / 2seventy bio Inc / CITADEL ADVISORS LLC - SC 13G/A Passive Investment

SC 13G/A 1 tm243953d18sc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G* (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO § 240.13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO § 240.13d-2 (Amendment No. 1)* 2seventy bio, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (the “Shares”) (Tit

February 14, 2024 SC 13G/A

MX:TSVT / 2seventy bio Inc / BAKER BROS. ADVISORS LP - SC 13G/A Passive Investment

SC 13G/A 1 tm242424d4sc13ga.htm SC 13G/A SCHEDULE 13G SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 Under the Securities Exchange Act of 1934 (Amendment No. 1)* 2seventy bio, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 901384107 (CUSIP Number) December 31, 2023 (Date of Event which Requires Filing of this Statement) Check the appropriate

February 13, 2024 SC 13G/A

MX:TSVT / 2seventy bio Inc / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SC 13G/A 1 tv0152-2seventybioinc.htm SCHEDULE 13G/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 2)* Name of issuer: 2seventy bio Inc Title of Class of Securities: Common Stock CUSIP Number: 901384107 Date of Event Which Requires Filing of this Statement: December 29, 2023 Check the appropriate box to designate the

February 5, 2024 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 5, 2024 2seventy bio, 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): February 5, 2024 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission Fil

February 5, 2024 EX-99.1

Bristol Myers Squibb and 2seventy bio Share Update on U.S. FDA Oncologic Drugs Advisory Committee Meeting for

Bristol Myers Squibb and 2seventy bio Share Update on U.S. FDA Oncologic Drugs Advisory Committee Meeting for Abecma in Triple-Class Exposed Multiple Myeloma Based on KarMMa-3 Study (PRINCETON, N.J., & CAMBRIDGE, Mass., February 5, 2024) – Bristol Myers Squibb (NYSE: BMY) and 2seventy bio, Inc. (Nasdaq: TSVT) today announced that a notice was published in the Federal Register that the U.S. Food an

February 2, 2024 8-K/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) 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 29, 2

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A (Amendment No. 1) 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 29, 2024 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporat

February 1, 2024 SC 13G/A

MX:TSVT / 2seventy bio Inc / MILLENNIUM MANAGEMENT LLC Passive Investment

SC 13G/A 1 TSVTSC13GA.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (AMENDMENT NO. 1) 2SEVENTY BIO, INC. (Name of Issuer) COMMON STOCK, PAR VALUE $0.0001 PER SHARE (Title of Class of Securities) 901384107 (CUSIP Number) DECEMBER 31, 2023 (Date of event which requires filing of this statement) Check the appropriate

January 30, 2024 EX-10.2

Executive Employment Agreement between 2seventy bio, Inc. and William Baird, dated as of January 29, 2024 (incorporated by reference to Exhibit 10.2 to Current Report on Form 8-K filed on January 30, 2024).

EMPLOYMENT AGREEMENT This Employment Agreement (“Agreement”) by and between 2seventy bio, Inc.

January 30, 2024 EX-10.1

Amended and Restated Transitional Services Agreement between 2seventy bio, Inc. and Nick Leschly, dated as of March 29, 2024 (incorporated by reference to Exhibit 10.1 to Current Report on Form 8-K filed on April 1, 2024).

January 29, 2024 Nick Leschly Re: Transitional Services Agreement Dear Nick: This letter (the “Agreement”) follows our conversations regarding your employment with 2seventy bio, Inc.

January 30, 2024 EX-99.1

2seventy bio Announces New Strategic Path Forward -Company to focus exclusively on commercialization and development of Abecma, in partnership with Bristol Myers Squibb – -Company to sell R&D pipeline to Regeneron to launch Regeneron Cell Medicines b

2seventy bio Announces New Strategic Path Forward -Company to focus exclusively on commercialization and development of Abecma, in partnership with Bristol Myers Squibb – -Company to sell R&D pipeline to Regeneron to launch Regeneron Cell Medicines business led by 2seventy bio’s Chief Scientific Officer, Philip Gregory -Chip Baird named incoming Chief Executive Officer; Nick Leschly named incoming Chairman of Board of Directors - -Expected annual cost savings of approximately $150 million in 2024 and $200 million in 2025; cash runway extended beyond 2027 - -Conference call to be held today at 8:00 a.

January 30, 2024 EX-10.3

Executive Employment Agreement between 2seventy bio, Inc. and Victoria Eatwell, dated as of January 29, 2024 (incorporated by reference to Exhibit 10.3 to Current Report on Form 8-K filed on January 30, 2024).

EMPLOYMENT AGREEMENT This Employment Agreement (“Agreement”) by and between 2seventy bio, Inc.

January 30, 2024 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): January 28, 2024 2seventy bio, 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): January 28, 2024 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fil

January 5, 2024 S-8

As filed with the Securities and Exchange Commission on January 5, 2024

As filed with the Securities and Exchange Commission on January 5, 2024 Registration No.

January 5, 2024 EX-FILING FEES

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) 2seventy bio, Inc.

December 12, 2023 EX-99.2

At median follow-up of more than 30 months, Abecma maintained a 51% reduction in risk of disease progression or death with median PFS of 13.8 months compared with 4.4 months for standard regimens Responses were significantly improved with Abecma and

Abecma Delivers Sustained Progression-Free Survival Versus Standard Regimens in Earlier Lines of Therapy for Relapsed and Refractory Multiple Myeloma Based on Longer-Term Follow-up from KarMMa-3 December 12, 2023 7:30 PM EST At median follow-up of more than 30 months, Abecma maintained a 51% reduction in risk of disease progression or death with median PFS of 13.

December 12, 2023 8-K

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 Exchange Act of 1934 Date of Report (Date of earliest event reported): December 11, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission Fi

December 12, 2023 EX-99.1

2023 ASH Annual Meeting Clinical Data December 12, 2023 2 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”. These statements include, but are not limited

2023 ASH Annual Meeting Clinical Data December 12, 2023 2 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”.

December 1, 2023 10-K/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A AMENDMENT NO. 1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K/A AMENDMENT NO. 1 (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For transition period from to Commission File Number 001-40791 2

December 1, 2023 10-Q/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q/A AMENDMENT NO. 1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q/A AMENDMENT NO. 1 ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-40791

December 1, 2023 10-Q/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q/A AMENDMENT NO. 1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q/A AMENDMENT NO. 1 ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-40791 2sev

December 1, 2023 CORRESP

December 1, 2023

December 1, 2023 VIA EDGAR Securities and Exchange Commission Division of Corporate Finance Office of Life Sciences 100 F Street, N.

December 1, 2023 10-Q/A

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q/A AMENDMENT NO. 1

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q/A AMENDMENT NO. 1 ☒ 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 001-40791 2se

November 20, 2023 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): November 20, 2023 2seventy bio, 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): November 20, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

November 20, 2023 EX-99.1

Bristol Myers Squibb and 2seventy bio Provide Update on U.S. FDA Review of sBLA for Abecma (idecabtagene vicleucel) in Earlier Lines of Therapy for Triple-Class Exposed Relapsed or Refractory Multiple Myeloma

Bristol Myers Squibb and 2seventy bio Provide Update on U.S. FDA Review of sBLA for Abecma (idecabtagene vicleucel) in Earlier Lines of Therapy for Triple-Class Exposed Relapsed or Refractory Multiple Myeloma November 20, 2023 06:59 AM Eastern Standard Time PRINCETON, N.J. & CAMBRIDGE, Mass.-(BUSINESS WIRE)- Bristol Myers Squibb (NYSE: BMY) and 2seventy bio, Inc. (Nasdaq: TSVT) today announced the

November 14, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended September 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-40791 2seventy bio, Inc

November 14, 2023 EX-99.1

2seventy bio Reports Third Quarter Financial Results and Recent Operational Progress Abecma (idecabtagene vicleucel) data to be presented at ASH 2023; multiple new analyses of KarMMa-3 and KarMMa-2c add to growing body of data supporting the potentia

2seventy bio Reports Third Quarter Financial Results and Recent Operational Progress Abecma (idecabtagene vicleucel) data to be presented at ASH 2023; multiple new analyses of KarMMa-3 and KarMMa-2c add to growing body of data supporting the potential safety and efficacy of Abecma in earlier lines of treatment Abecma generated $69 million U.

November 14, 2023 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): November 14, 2023 2seventy bio, 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): November 14, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

November 9, 2023 SC 13G/A

MX:TSVT / 2seventy bio Inc / WELLINGTON MANAGEMENT GROUP LLP - SEC SCHEDULE 13G Passive Investment

SC 13G/A 1 SEC13GFiling.htm SEC SCHEDULE 13G UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 3 )* 2seventy bio, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 901384107 (CUSIP Number) October 31, 2023 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to d

October 26, 2023 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): October 26, 2023 2seventy bio, 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): October 26, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fil

September 13, 2023 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): September 13, 2023 2seventy bio,

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): September 13, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission F

September 13, 2023 EX-99.1

Unleash Time 2seventy bio company presentation September 2023 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”. These statements include, but are not lim

a2seventyseptember2023ir Unleash Time 2seventy bio company presentation September 2023 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”.

September 12, 2023 EX-99.1

2seventy bio Announces Strategic Restructuring to Prioritize Growth of Abecma, Streamline Pipeline Advancement and Preserve Financial Runway Approximately 40% workforce reduction combined with related actions expected to achieve $130+ million savings

2seventy bio Announces Strategic Restructuring to Prioritize Growth of Abecma, Streamline Pipeline Advancement and Preserve Financial Runway Approximately 40% workforce reduction combined with related actions expected to achieve $130+ million savings in the 2024-2025 period; projected cash runway into at least 2026 to support focus on long-term mission Company to internally advance fewer pipeline

September 12, 2023 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): September 8, 2023 2seventy bio, 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): September 8, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

September 6, 2023 SC 13G

MX:TSVT / 2seventy bio Inc / Kynam Capital Management, LP Passive Investment

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

August 14, 2023 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): August 14, 2023 2seventy bio, 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): August 14, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

August 14, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended June 30, 2023 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the transition period from to Commission file number 001-40791 2seventy bio, Inc. (Ex

August 14, 2023 EX-10.1

Second Amendment to Amended and Restated Co-Development, Co-Promote and Profit Share Agreement, between 2seventy bio, Inc., Celgene Corporation and Celgene Investment Company LLC, dated June 23, 2023 (incorporated by reference to Exhibit 10.1 to Quarterly Report on Form 10-Q filed on August 14, 2023).

Confidential EXECUTION VERSION SECOND AMENDMENT TO AMENDED AND RESTATED CO-DEVELOPMENT, CO-PROMOTE AND PROFIT SHARE AGREEMENT By and Between 2SEVENTY BIO, INC.

August 14, 2023 EX-99.1

2seventy bio Reports Second Quarter Financial Results and Recent Operational Progress Abecma (idecabtagene vicleucel) generated $115 million U.S. commercial revenue in 2Q 2023, supporting lower end of U.S. revenue guidance of $470-570 million 2sevent

2seventy bio Reports Second Quarter Financial Results and Recent Operational Progress Abecma (idecabtagene vicleucel) generated $115 million U.

July 27, 2023 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 27, 2023 2seventy bio, 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): July 27, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File N

June 14, 2023 8-K

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 Exchange Act of 1934 Date of Report (Date of earliest event reported): June 14, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File N

June 14, 2023 EX-99.1

Unleash Time 2seventy bio company presentation June 2023 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”. These statements include, but are not limited

a2seventyjune2023irprese Unleash Time 2seventy bio company presentation June 2023 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”.

June 14, 2023 EX-99.2

2seventy bio Announces Clinical Study Pause of PLAT-08 Trial of SC-DARIC33 in Acute Myeloid Leukemia

2seventy bio Announces Clinical Study Pause of PLAT-08 Trial of SC-DARIC33 in Acute Myeloid Leukemia CAMBRIDGE, Mass.

June 13, 2023 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): June 12, 2023 2seventy bio, 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): June 12, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File N

May 19, 2023 EX-99.2

2seventy bio Presents Late-Breaking Results for SC-DARIC33, an Investigational CD33-Targeting CAR T in Pediatric and Young Adults with Relapsed or Refractory Acute Myeloid Leukemia Results of preliminary correlative analysis from the PLAT-08 study sh

final2seventybioasgctlb 2seventy bio Presents Late-Breaking Results for SC-DARIC33, an Investigational CD33-Targeting CAR T in Pediatric and Young Adults with Relapsed or Refractory Acute Myeloid Leukemia Results of preliminary correlative analysis from the PLAT-08 study show rapamycin-regulated in vivo expansion and activation of SC-DARIC33 T cells as well as concurrent anti-CD33 activity Enhance

May 19, 2023 EX-99.1

2seventy R&D Deep Dive: ASGCT and Beyond May 19, 2023 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements” within the meaning of the Private Securities Litig

finalv2rddeepdivemaster 2seventy R&D Deep Dive: ASGCT and Beyond May 19, 2023 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements” within the meaning of the Private Securities Litigation Reform Act of 1995.

May 19, 2023 8-K

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 Exchange Act of 1934 Date of Report (Date of earliest event reported): May 19, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File Nu

May 17, 2023 EX-99.1

2seventy bio Presents Broad Range of New Data Highlighting Novel Approaches Across its Cell Therapies Portfolio bbT369, a dual-targeted (CD79a/CD20) and CBLB gene edited autologous CAR T for non-Hodgkin lymphoma, showed edit-driven enhanced T cell ac

2seventy bio Presents Broad Range of New Data Highlighting Novel Approaches Across its Cell Therapies Portfolio bbT369, a dual-targeted (CD79a/CD20) and CBLB gene edited autologous CAR T for non-Hodgkin lymphoma, showed edit-driven enhanced T cell activity in multiple preclinical models RESET, a novel TCR coupled antigen receptor architecture, displayed markedly increased targeting sensitivity and pharmacologically controlled anti-tumor activity A novel TGFβ switch receptor drove enhanced MAGE-A4 TCR anti-tumor activity with a favorable safety profile CAMBRIDGE, Mass.

May 17, 2023 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): May 17, 2023 2seventy bio, 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): May 17, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File Nu

May 15, 2023 SC 13G

MX:TSVT / 2seventy bio Inc / MILLENNIUM MANAGEMENT LLC Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 2SEVENTY BIO, INC. (Name of Issuer) COMMON STOCK, PAR VALUE $0.0001 PER SHARE (Title of Class of Securities) 901384107 (CUSIP Number) MAY 5, 2023 (Date of event which requires filing of this statement) Check the appropriate box to designate the rule pursuant to which this

May 10, 2023 EX-10.1

License Agreement by and between bluebird bio, Inc. and Institut Pasteur, dated September 8, 2011, as amended.

Certain information indicated with [***] in this document has been omitted from this exhibit because it is both (i) not material and (ii) would be competitively harmful if publicly disclosed.

May 10, 2023 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ☒ QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 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 001-40791 2seventy bio, Inc. (E

May 3, 2023 EX-99.1

2seventy bio Reports First Quarter Financial Results and Recent Operational Progress Abecma (idecabtagene vicleucel) generated $118 million U.S. commercial revenue in 1Q 2023, supporting upper end of U.S. revenue guidance of $470-570 million U.S. FDA

2seventy bio Reports First Quarter Financial Results and Recent Operational Progress Abecma (idecabtagene vicleucel) generated $118 million U.

May 3, 2023 8-K

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 3, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File Num

May 1, 2023 8-K

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): May 1, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File Num

May 1, 2023 DEFA14A

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

May 1, 2023 DEF 14A

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 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)

May 1, 2023 SC 13G

MX:TSVT / 2seventy bio Inc / CITADEL ADVISORS LLC - SC 13G Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G* (Rule 13d-102) INFORMATION TO BE INCLUDED IN STATEMENTS FILED PURSUANT TO § 240.13d-1(b), (c), AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO § 240.13d-2 (Amendment No. )* 2seventy bio, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (the “Shares”) (Title of Class of Securities) 901384107 (CUSIP

May 1, 2023 EX-99.1

2seventy bio and Novo Nordisk Collaboration Delivers Key Proof of Concept Data, Triggering $15 Million Preclinical Milestone in In Vivo Gene Editing Hemophilia A Program 2seventy bio plans to present data at virtual Research and Development deep dive

2seventy bio and Novo Nordisk Collaboration Delivers Key Proof of Concept Data, Triggering $15 Million Preclinical Milestone in In Vivo Gene Editing Hemophilia A Program 2seventy bio plans to present data at virtual Research and Development deep dive on May 19, 2023 CAMBRIDGE, Mass.

May 1, 2023 EX-99.1

JOINT FILING AGREEMENT

EXHIBIT 99.1 JOINT FILING AGREEMENT The undersigned hereby agree that the Statement on Schedule 13G filed herewith (and any amendments thereto), relating to the Shares of 2seventy bio, Inc., a Massachusetts corporation, is being filed jointly with the Securities and Exchange Commission pursuant to Rule 13d-1(c) under the Securities Exchange Act of 1934, as amended, on behalf of each of the undersi

April 27, 2023 8-K

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 27, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

April 18, 2023 PRE 14A

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 x Filed by a party other than the Registrant ☐ Check the appropriate box: x Preliminary Proxy Statement □ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)

April 17, 2023 EX-99.1

Regulatory Applications Accepted Across Three Regions Globally for Abecma for Earlier Use in Adults with Triple-Class Exposed Relapsed and/or Refractory Multiple Myeloma U.S. FDA accepted Bristol Myers Squibb and 2seventy bio’s supplemental Biologics

Regulatory Applications Accepted Across Three Regions Globally for Abecma for Earlier Use in Adults with Triple-Class Exposed Relapsed and/or Refractory Multiple Myeloma U.

April 17, 2023 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): April 17, 2023 2seventy bio, 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): April 17, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

March 17, 2023 EX-FILING FEES

Filing Fee Table.

Exhibit 107 Calculation of Filing Fee Table Form S-8 (Form Type) 2seventy bio, Inc.

March 17, 2023 S-8

As filed with the Securities and Exchange Commission on March 17, 2023

As filed with the Securities and Exchange Commission on March 17, 2023 Registration No.

March 16, 2023 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): March 16, 2023 2seventy bio, 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 16, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

March 16, 2023 EX-10.17

and Nicola Heffron, dated February 17, 2023.

Severance Agreement Between Globalization Partners Switzerland SA Route de Frontenex 86bis 1208 Geneve Switzerland (the Employer) and Nicola Heffron Dorfstrasse 20 Allenwinden Zug 6319 Switzerland (the Employee) The Employer and the Employee are also referred to as Party or together as Parties.

March 16, 2023 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-K (Mark One) ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2022 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For transition period from to Commission File Number 001-40791 2seventy bio, Inc.

March 16, 2023 EX-3.2

Amended and Restated Bylaws of 2seventy bio, Inc. (incorporated by reference to Exhibit 3.2 to Annual Report on Form 10-K filed on March 16, 2023).

AMENDED AND RESTATED BY-LAWS OF 2SEVENTY BIO, 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 subsequently be c

March 16, 2023 EX-99.1

2seventy bio Reports Fourth Quarter and Full Year 2022 Financial Results and Recent Operational Progress Abecma (idecabtagene vicleucel) generated $94M U.S. commercial revenue in 4Q 2022, $297M in FY 2022; anticipate $470-$570M U.S. revenue in 2023 P

2seventy bio Reports Fourth Quarter and Full Year 2022 Financial Results and Recent Operational Progress Abecma (idecabtagene vicleucel) generated $94M U.

March 16, 2023 EX-10.18

Consulting Agreement between 2seventy bio, Inc. and Nicola Heffron, dated February 21, 2023.

CONSULTING AGREEMENT THIS CONSULTING AGREEMENT (together with the attached Business Terms Exhibit, the “Agreement”), is made as of February 21, 2023 (the “Effective Date”) by and between 2seventy bio, Inc.

March 16, 2023 EX-21.1

Subsidiaries of the Registrant.

Exhibit 21.1 SUBSIDIARIES OF THE REGISTRANT Name of Subsidiary Jurisdiction of Formation 2seventy bio Securities Corporation Massachusetts

March 8, 2023 EX-99.1

2seventy bio Announces Appointment of Wei Lin, M.D. to Board of Directors

2seventy bio Announces Appointment of Wei Lin, M.D. to Board of Directors CAMBRIDGE, Mass.— March 8, 2023—2seventy bio, Inc. (Nasdaq: TSVT) today announced the appointment of Wei Lin, M.D. to the company’s Board of Directors, effective immediately. “We are thrilled to welcome Dr. Wei Lin to 2seventy’s Board during an exciting time in our Company’s growth,” said Nick Leschly, chief kairos officer.

March 8, 2023 8-K

Regulation FD Disclosure, 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): March 7, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File N

March 7, 2023 EX-99.1

Unleash Time 2seventy bio company presentation March 2023 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”. These statements include, but are not limited

exhibit99 Unleash Time 2seventy bio company presentation March 2023 Cautionary note regarding forward-looking statements These slides and the accompanying oral presentation may contain “forward-looking statements”.

March 7, 2023 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): March 7, 2023 2seventy bio, 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 7, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File N

March 1, 2023 EX-99.2

2seventy bio Announces Pricing of Upsized Public Offering of Common Stock

Exhibit 99.2 2seventy bio Announces Pricing of Upsized Public Offering of Common Stock February 28, 2023 – 2seventy bio, Inc. (“2seventy bio”) (Nasdaq: TSVT), a cell and gene therapy company focused on the research, development, and commercialization of transformative treatments for cancer, announced today the pricing of a follow on underwritten public offering of 10,869,566 shares of its common s

March 1, 2023 EX-99.1

2seventy bio Announces Proposed Public Offering of Common Stock

Exhibit 99.1 2seventy bio Announces Proposed Public Offering of Common Stock February 28, 2023 – 2seventy bio, Inc. (“2seventy bio”) (Nasdaq: TSVT), a cell and gene therapy company focused on the research, development, and commercialization of transformative treatments for cancer, announced today that it has commenced an underwritten public offering of $100 million of shares of its common stock. A

March 1, 2023 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 28, 2023 2seventy bio, 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): February 28, 2023 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

March 1, 2023 424B5

10,869,566 Shares Common Stock

Filed Pursuant to Rule 424(b)(5) Registration No. 333-268222 PROSPECTUS SUPPLEMENT (To Prospectus dated November 18, 2022) 10,869,566 Shares Common Stock We are selling 10,869,566 shares of our common stock. Our common stock is listed on The Nasdaq Global Select Market under the symbol “TSVT.” The last reported sale price of our common stock on The Nasdaq Global Select Market on February 28, 2023

March 1, 2023 EX-1.1

Underwriting Agreement, dated as of February 28, 2023, by and between the Company and Goldman Sachs & Co. LLC, Cowen and Company, LLC, and SVB Securities LLC, as representatives of the several underwriters named

EX-1.1 2 exhibit11-8xk312023.htm EX-1.1 Exhibit 1.1 2seventy bio, Inc. Common Stock Underwriting Agreement February 28, 2023 Goldman Sachs & Co. LLC, Cowen and Company, LLC, SVB Securities LLC, As representatives (the “Representatives”) of the several Underwriters named in Schedule I hereto, c/o Goldman Sachs & Co. LLC 200 West Street, New York, New York 10282-2198 c/o Cowen and Company, LLC 599 L

February 28, 2023 424B5

Subject to Completion, dated February 28, 2023

Filed Pursuant to Rule 424(b)(5) Registration No. 333-268222 The information in this preliminary prospectus supplement is not complete and may be changed. A registration statement has been filed with the Securities and Exchange Commission and is effective. This prospectus supplement is not an offer to sell these securities and it is not soliciting an offer to buy these securities in any jurisdicti

February 28, 2023 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 28, 2023 2seventy bio, 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): February 28, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

February 28, 2023 EX-99.1

1

Exhibit 99.1 Item 1A. Risk Factors An investment in shares of our common stock involves a high degree of risk. You should carefully consider the following information about these risks, together with the other information appearing in our Annual Report on Form 10-K filed with the SEC on March 22, 2022 and our subsequent quarterly reports on Form 10-Q, before deciding to invest in our common stock.

February 23, 2023 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 17, 2023 2seventy bio, 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): February 17, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

February 14, 2023 EX-99.1

AGREEMENT

EX-99.1 2 tm234999d24ex99-1.htm EXHIBIT 99.1 EXHIBIT 99.1 AGREEMENT In accordance with Rule 13d-1(k)(1) under the Securities Exchange Act of 1934, as amended, the undersigned hereby agree that this Statement on Schedule 13G relating to the Common Stock of 2seventy bio, Inc. is being filed with the Securities and Exchange Commission on behalf of each of them. February 14, 2023 BAKER BROS. ADVISORS

February 14, 2023 SC 13G

MX:TSVT / 2seventy bio Inc / BAKER BROS. ADVISORS LP - SC 13G Passive Investment

SC 13G 1 tm234999d24sc13g.htm SC 13G SCHEDULE 13G SECURITIES AND EXCHANGE COMMISSION WASHINGTON, DC 20549 Under the Securities Exchange Act of 1934 (Amendment No. )* 2seventy bio, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 901384107 (CUSIP Number) December 31, 2022 (Date of Event which Requires Filing of this Statement) Check the appropriate box

February 14, 2023 SC 13G/A

MX:TSVT / 2seventy bio Inc / EcoR1 Capital, LLC Passive Investment

SC 13G/A 1 tsvt13ga2.htm UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2) 2seventy bio, Inc. (Name of Issuer) Common Stock, par value $0.0001 per share (Title of Class of Securities) 901384107 (CUSIP Number) December 31, 2022 (Date of Event Which Requires Filing of this Statement) Check the appropriate

February 10, 2023 EX-99.1

Abecma (idecabtagene vicleucel) Reduced the Risk of Disease Progression or Death by 51% Versus Standard Regimens in Earlier Lines of Therapy for Relapsed and Refractory Multiple Myeloma Based on Results from Phase 3 KarMMa-3 Study Abecma more than tr

Abecma (idecabtagene vicleucel) Reduced the Risk of Disease Progression or Death by 51% Versus Standard Regimens in Earlier Lines of Therapy for Relapsed and Refractory Multiple Myeloma Based on Results from Phase 3 KarMMa-3 Study Abecma more than tripled progression-free survival (13.

February 10, 2023 8-K

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 Exchange Act of 1934 Date of Report (Date of earliest event reported): February 10, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

February 9, 2023 SC 13G/A

MX:TSVT / 2seventy bio Inc / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SC 13G/A 1 tv0137-2seventybioinc.htm SCHEDULE 13G/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 1)* Name of issuer: 2seventy bio Inc. Title of Class of Securities: Common Stock CUSIP Number: 901384107 Date of Event Which Requires Filing of this Statement: December 30, 2022 Check the appropriate box to designate th

February 6, 2023 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 1, 2023 2seventy bio, 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): February 1, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fil

February 6, 2023 SC 13G/A

MX:TSVT / 2seventy bio 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. 2 )* 2seventy bio, Inc. (Name of Issuer) Common Stock (Title of Class of Securities) 901384107 (CUSIP Number) December 30, 2022 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Sch

February 2, 2023 8-K

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): February 2, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fil

January 9, 2023 EX-99.1

Unleash Time 2seventy bio company presentation January 2023 Cautionary note regarding forward-looking statements 2 These slides and the accompanying oral presentation may contain “forward-looking statements”. These statements include, but are not lim

Unleash Time 2seventy bio company presentation January 2023 Cautionary note regarding forward-looking statements 2 These slides and the accompanying oral presentation may contain “forward-looking statements”.

January 9, 2023 EX-99.2

2seventy bio Provides Company Outlook for 2023 Anticipate $470-$570M topline U.S. revenue Abecma (idecabtagene vicleucel) in 2023, shared equally with Bristol Myers Squibb (BMS) KarMMa-3 data to be presented at EBMT-EHA 5th European CAR T-cell Meetin

EX-99.2 3 ex992tsvt8-k192023vf.htm EX-99.2 2seventy bio Provides Company Outlook for 2023 Anticipate $470-$570M topline U.S. revenue Abecma (idecabtagene vicleucel) in 2023, shared equally with Bristol Myers Squibb (BMS) KarMMa-3 data to be presented at EBMT-EHA 5th European CAR T-cell Meeting on February 10, 2023; 3L+ sBLA submission for Abecma targeted completion in Q1 Expanded translational col

January 9, 2023 8-K

Regulation FD Disclosure, Financial Statements and Exhibits, Results of Operations and Financial Condition, 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): January 9, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

January 6, 2023 EX-99.1

2seventy bio Announces Expanded Translational Collaboration with Regeneron to Develop New Cell Therapy-Based Combinations for Solid Tumors Collaboration Leverages 2seventy's Platform for T Cell Therapy Research and Development with Regeneron Antibodi

EX-99.1 2 ex9911.htm EX-99.1 2seventy bio Announces Expanded Translational Collaboration with Regeneron to Develop New Cell Therapy-Based Combinations for Solid Tumors Collaboration Leverages 2seventy's Platform for T Cell Therapy Research and Development with Regeneron Antibodies and Bispecifics to Explore Multiplex Combination Approaches Regeneron Investing $20 million in 2seventy Equity; Regene

January 6, 2023 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): January 6, 2023 2seventy bio, 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): January 6, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

January 5, 2023 8-K

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): January 4, 2023 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

November 18, 2022 8-K

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): November 18, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

November 18, 2022 EX-1.1

Sales Agreement, dated November 18, 2022 between 2seventy bio, Inc. and Cowen and Company, LLC.

EX-1.1 2 exhibit11-tvstx8xk.htm EX-1.1 Exhibit 1.1 2SEVENTY BIO, INC. $150,000,000 COMMON STOCK SALES AGREEMENT November 18, 2022 Cowen and Company, LLC 599 Lexington Avenue New York, NY 10022 Ladies and Gentlemen: 2seventy bio, Inc. (the “Company”), confirms its agreement (this “Agreement”) with Cowen and Company, LLC (“Cowen”), as follows: 1. Issuance and Sale of Shares. The Company agrees that,

November 18, 2022 424B5

Up to $150,000,000 Common Stock

PROSPECTUS SUPPLEMENT (To Prospectus dated November 18, 2022) Filed Pursuant to Rule 424(b)(5) Registration No.

November 16, 2022 CORRESP

VIA EDGAR

CORRESP 1 filename1.htm VIA EDGAR November 16, 2022 United States Securities and Exchange Commission Division of Corporation Finance Mail Stop 4561 100 F Street, N.E. Washington, D.C. 20549 Re: 2seventy bio, Inc. Acceleration Request for Registration Statement on Form S-3 File No. 333-268222 Ladies and Gentlemen, Pursuant to Rule 461 under the Securities Act of 1933, as amended (the “Act”), 2seven

November 7, 2022 EX-4.6

Form of Subordinated Indenture between Registrant and one or more trustees to be named

Exhibit 4.6 2SEVENTY BIO, INC. Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [l], 202[l] Subordinated Debt Securities TABLE OF CONTENTS(1) Article 1 DEFINITIONS 1 Section 1.01 Definitions of Terms. 1 Article 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES 4 Section 2.01 Designation and Terms of Securities. 4 Section 2.02 Form of Securities and Trustee?s Certif

November 7, 2022 EX-99.1

2seventy bio Reports Third Quarter Financial Results and Recent Operational Progress Strategic partnership with JW Therapeutics to accelerate development of cell therapies targeted to solid tumors Abecma generated $75M U.S. commercial revenue in 3Q;

EX-99.1 2 q3earnings.htm EX-99.1 2seventy bio Reports Third Quarter Financial Results and Recent Operational Progress Strategic partnership with JW Therapeutics to accelerate development of cell therapies targeted to solid tumors Abecma generated $75M U.S. commercial revenue in 3Q; continues to track toward upper end of $250-$300M revenue guidance for 2022 Ended quarter with $324.5M cash, cash equ

November 7, 2022 EX-FILING FEES

Filing Fee Table

Exhibit 107 CALCULATION OF FILING FEE TABLES Form S-3 (Form Type) 2seventy bio, Inc.

November 7, 2022 8-K

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 7, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fil

November 7, 2022 S-3

As filed with the Securities and Exchange Commission on November 7, 2022

As filed with the Securities and Exchange Commission on November 7, 2022 Registration No.

November 7, 2022 EX-4.5

Form of Senior Indenture between Registrant and one or more trustees to be named

Exhibit 4.5 2SEVENTY BIO, INC. Issuer AND [TRUSTEE], Trustee INDENTURE Dated as of [l], 202[l] Senior Debt Securities TABLE OF CONTENTS1 Page Article 1 DEFINITIONS 1 Section 1.01 Definitions of Terms. Article 2 ISSUE, DESCRIPTION, TERMS, EXECUTION, REGISTRATION AND EXCHANGE OF SECURITIES 4 Section 2.01 Designation and Terms of Securities. 4 Section 2.02 Form of Securities and Trustee?s Certificate

November 7, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended 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 001-40791 2seventy bio, Inc

November 3, 2022 EX-99.1

2seventy bio to Present Data from KarMMa-2 Study of Abecma (idecabtagene vicleucel) at the 64th American Society of Hematology (ASH) Annual Meeting and Exposition Data from KarMMa-2 Cohorts 2a and 2c suggest potential for early treatment with Abecma

2seventy bio to Present Data from KarMMa-2 Study of Abecma (idecabtagene vicleucel) at the 64th American Society of Hematology (ASH) Annual Meeting and Exposition Data from KarMMa-2 Cohorts 2a and 2c suggest potential for early treatment with Abecma in patients with second-line and newly diagnosed multiple myeloma Data suggest promising outcomes can be achieved treating patients with suboptimal response after transplant Results support further evaluation of Abecma in patients with newly diagnosed multiple myeloma in KarMMa-9 study (CAMBRIDGE, Mass.

November 3, 2022 8-K

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): November 3, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fil

November 1, 2022 POS AM

As filed with the Securities and Exchange Commission on November 1, 2022

POS AM 1 tsvtposam.htm POS AM As filed with the Securities and Exchange Commission on November 1, 2022 Registration Statement No. 333-264544 UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 POST-EFFECTIVE AMENDMENT NO. 1 TO FORM S-1 ON FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 2seventy bio, Inc. (Exact name of registrant as specified in its charter) De

October 27, 2022 8-K

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): October 27, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fil

October 27, 2022 424B3

Up to 13,934,427 Shares of Common Stock

Filed Pursuant to Rule 424(b)(3) Registration No. 333-264544 Prospectus Supplement No. 6 (to Prospectus dated May 6, 2022) Up to 13,934,427 Shares of Common Stock This prospectus supplement updates and supplements the prospectus dated May 6, 2022 (the ?Prospectus?), which forms a part of our Registration Statement on Form S-1 (333-264544). This prospectus supplement is being filed to update and su

October 27, 2022 EX-99.1

2seventy bio and JW Therapeutics Announce Strategic Partnership to Accelerate the Research and Development of T Cell-based Immunotherapies Initial focus on accelerating development of 2seventy bio’s MAGE-A4 program in solid tumors in China

2seventy bio and JW Therapeutics Announce Strategic Partnership to Accelerate the Research and Development of T Cell-based Immunotherapies Initial focus on accelerating development of 2seventy bio?s MAGE-A4 program in solid tumors in China CAMBRIDGE, Massachusetts, US, and Shanghai, China ? (BUSINESS WIRE)?October 27, 2022?2seventy bio, Inc.

September 7, 2022 8-K

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): September 7, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission Fi

September 7, 2022 EX-99.1

2seventy bio Announces Plans to Initiate KarMMa-9 Study of Abecma (idecabtagene vicleucel) in Newly Diagnosed Multiple Myeloma Patients This study will evaluate Abecma in patients with suboptimal response to transplant Data from KarMMa-3 and KarMMa-2

2seventy bio Announces Plans to Initiate KarMMa-9 Study of Abecma (idecabtagene vicleucel) in Newly Diagnosed Multiple Myeloma Patients This study will evaluate Abecma in patients with suboptimal response to transplant Data from KarMMa-3 and KarMMa-2 studies of Abecma will be presented at future medical meeting (CAMBRIDGE, Mass.

September 7, 2022 424B3

Up to 13,934,427 Shares of Common Stock

424B3 1 tsvt-424b3prosuppkarmma98xk.htm 424B3 Filed Pursuant to Rule 424(b)(3) Registration No. 333-264544 Prospectus Supplement No. 5 (to Prospectus dated May 6, 2022) Up to 13,934,427 Shares of Common Stock This prospectus supplement updates and supplements the prospectus dated May 6, 2022 (the “Prospectus”), which forms a part of our Registration Statement on Form S-1 (333-264544). This prospec

August 10, 2022 EX-99.1

Bristol Myers Squibb and 2seventy bio Announce Top-Line Results from KarMMa-3 Trial Showing Abecma (idecabtagene vicleucel) Significantly Improves Progression-Free Survival Versus Standard Regimens in Relapsed and Refractory Multiple Myeloma Abecma i

Bristol Myers Squibb and 2seventy bio Announce Top-Line Results from KarMMa-3 Trial Showing Abecma (idecabtagene vicleucel) Significantly Improves Progression-Free Survival Versus Standard Regimens in Relapsed and Refractory Multiple Myeloma Abecma is the first BCMA-directed CAR T cell therapy to demonstrate superiority versus standard regimens in relapsed and refractory multiple myeloma (PRINCETON, N.

August 10, 2022 EX-99.1

Join the Patient Mission Company Presentation August 2022 Cautionary note regarding forward-looking statements 2 These slides and the accompanying oral presentation may contain “forward-looking statements”. These statements include, but are not limit

Join the Patient Mission Company Presentation August 2022 Cautionary note regarding forward-looking statements 2 These slides and the accompanying oral presentation may contain ?forward-looking statements?.

August 10, 2022 8-K

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): August 10, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

August 10, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended 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 001-40791 2seventy bio, Inc. (Ex

August 10, 2022 424B3

Up to 13,934,427 Shares of Common Stock

Filed Pursuant to Rule 424(b)(3) Registration No. 333-264544 Prospectus Supplement No. 4 (to Prospectus dated May 6, 2022) Up to 13,934,427 Shares of Common Stock This prospectus supplement updates and supplements the prospectus dated May 6, 2022 (the ?Prospectus?), which forms a part of our Registration Statement on Form S-1 (333-264544). This prospectus supplement is being filed to update and su

August 10, 2022 EX-99.1

2seventy bio Reports Second Quarter Financial Results and Recent Operational Progress ABECMA generated $72M U.S. commercial revenue in 2Q; continues to track toward upper end of $250-$300M revenue guidance for 2022 Results from prespecified interim a

2seventy bio Reports Second Quarter Financial Results and Recent Operational Progress ABECMA generated $72M U.

August 10, 2022 8-K

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 10, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

August 10, 2022 8-K

Regulation FD Disclosure, 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): August 10, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File

June 13, 2022 8-K

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): June 8, 2022 2seventy bio, Inc. (Exact name of registrant as specified in its charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File Nu

June 13, 2022 424B3

Up to 13,934,427 Shares of Common Stock

Filed Pursuant to Rule 424(b)(3) Registration No. 333-264544 Prospectus Supplement No. 3 (to Prospectus dated May 6, 2022) Up to 13,934,427 Shares of Common Stock This prospectus supplement updates and supplements the prospectus dated May 6, 2022 (the ?Prospectus?), which forms a part of our Registration Statement on Form S-1 (333-264544). This prospectus supplement is being filed to update and su

June 3, 2022 8-K

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers

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 2, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or other jurisdiction of incorporation) (Commission File Nu

June 3, 2022 424B3

Up to 13,934,427 Shares of Common Stock

Filed Pursuant to Rule 424(b)(3) Registration No. 333-264544 Prospectus Supplement No. 2 (to Prospectus dated May 6, 2022) Up to 13,934,427 Shares of Common Stock This prospectus supplement updates and supplements the prospectus dated May 6, 2022 (the ?Prospectus?), which forms a part of our Registration Statement on Form S-1 (333-264544). This prospectus supplement is being filed to update and su

May 12, 2022 8-K

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 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File Nu

May 12, 2022 EX-10.1

First Addendum Executive Employment Agreement between Globalization Partners Switzerland SA and Nicola Heffron, dated as of March 7, 2022.

Certain information indicated with [***] in this document has been omitted from this exhibit because it is both (i) not material and (ii) would be competitively harmful if publicly disclosed.

May 12, 2022 EX-10.3

Patent License Agreement, dated August 31, 2015, by and between bluebird bio, Inc. and the National Institutes of Health

Certain information indicated with [***] in this document has been omitted from this exhibit because it is both (i) not material and (ii) would be competitively harmful if publicly disclosed.

May 12, 2022 EX-10.4

Amendment to License Agreement, dated April 25, 2022, by and between 2seventy bio, Inc. and the National Institutes of Health

Certain information indicated with [***] in this document has been omitted from this exhibit because it is both (i) not material and (ii) would be competitively harmful if publicly disclosed.

May 12, 2022 EX-10.2

Second Addendum to Executive Employment Agreement between Globalization Partners Switzerland SA and Nicola Heffron, dated as of March 25, 2022.

Certain information indicated with [***] in this document has been omitted from this exhibit because it is both (i) not material and (ii) would be competitively harmful if publicly disclosed.

May 12, 2022 424B3

Up to 13,934,427 Shares of Common Stock

424B3 1 tsvt424b351222.htm 424B3 Filed Pursuant to Rule 424(b)(3) Registration No. 333-264544 Prospectus Supplement No. 1 (to Prospectus dated May 6, 2022) Up to 13,934,427 Shares of Common Stock This prospectus supplement updates and supplements the prospectus dated May 6, 2022 (the “Prospectus”), which forms a part of our Registration Statement on Form S-1 (333-264544). This prospectus supplemen

May 12, 2022 EX-99.1

2seventy bio Reports First Quarter Financial Results and Recent Operational Progress First patients enrolled in clinical studies in bNHL and AML ABECMA generated $56M U.S. commercial revenue in 1Q; continues to track toward upper end of $250-$300M U.

2seventy bio Reports First Quarter Financial Results and Recent Operational Progress First patients enrolled in clinical studies in bNHL and AML ABECMA generated $56M U.

May 12, 2022 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 10-Q ? QUARTERLY REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the quarterly period ended March 31, 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 001-40791 2seventy bio, Inc. (E

May 6, 2022 424B3

13,934,427 Shares Common Stock

Filed pursuant to Rule 424(b)(3) Registration No. 333-264544 PROSPECTUS 13,934,427 Shares Common Stock This prospectus relates to the resale of up to 13,934,427 shares of our common stock by the selling stockholders named in this prospectus or in supplements to this prospectus. See ?Selling Stockholders.? We are registering the applicable shares of our common stock to provide the selling stockhold

May 4, 2022 CORRESP

VIA EDGAR

VIA EDGAR May 4, 2022 United States Securities and Exchange Commission Division of Corporation Finance Mail Stop 4561 100 F Street, N.

April 29, 2022 8-K

Entry into a Material Definitive Agreement

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 27, 2022 2seventy bio, Inc. (Exact name of Registrant as Specified in Its Charter) Delaware 001-40791 86-3658454 (State or Other Jurisdiction of Incorporation) (Commission File

April 28, 2022 EX-FILING FEES

Filing Fee Table

Exhibit 107 Calculation of Filing Fee Tables Form S-1 (Form Type) 2seventy bio, Inc.

April 28, 2022 S-1

Power of Attorney (incorporated by reference to Exhibit 24.1 to the Registrant’s registration statement on Form S-1 filed with the SEC on April 28, 2022).

As filed with the Securities and Exchange Commission on April 28, 2022. Registration No. 333- UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM S-1 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 2seventy bio, Inc. (Exact Name of Registrant as Specified in Its Charter) Delaware 2834 86-3658454 (State or Other Jurisdiction of Incorporation or Organization) (Primar

April 26, 2022 DEFA14A

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 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)

Fintel data has been cited in the following publications:
Daily Mail Fox Business Business Insider Wall Street Journal The Washington Post Bloomberg Financial Times Globe and Mail
NASDAQ.com Reuters The Guardian Associated Press FactCheck.org Snopes Politifact
Federal Register The Intercept Forbes Fortune Magazine TheStreet Time Magazine Canadian Broadcasting Corporation International Business Times
Cambridge University Press Investopedia MarketWatch NY Daily News Entrepreneur Newsweek Barron's El Economista