BIIB / Biogen Inc. - Zgłoszenia SEC, Raport roczny, o pełnomocnictwie

CONTINGENT VALUE RIGHTS AGREEMENT

EX-10.1 Exhibit 10.1 EXECUTION VERSION CONTINGENT VALUE RIGHTS AGREEMENT THIS CONTINGENT VALUE RIGHTS AGREEMENT, dated as of May 14, 2026 (this “Agreement”), is entered into by and among Biogen Inc., a Delaware corporation (the “Parent”), Apellis Pharmaceuticals, Inc., a Delaware corporation (together with any successor thereto, the “Company”), and Equiniti Trust Company, LLC, a New York limited l

TERM LOAN CREDIT AGREEMENT Dated as of May 12, 2026 BIOGEN INC., as the Borrower, U.S. BANK NATIONAL ASSOCIATION, as the Administrative Agent, BANCO BILBAO VIZCAYA ARGENTARIA, S.A. NEW YORK BRANCH, as Syndication Agent BANK OF AMERICA, N.A., JPMORGAN

EX-10.2 Exhibit 10.2 EXECUTION VERSION TERM LOAN CREDIT AGREEMENT Dated as of May 12, 2026 among BIOGEN INC., as the Borrower, U.S. BANK NATIONAL ASSOCIATION, as the Administrative Agent, BANCO BILBAO VIZCAYA ARGENTARIA, S.A. NEW YORK BRANCH, as Syndication Agent BANK OF AMERICA, N.A., JPMORGAN CHASE BANK, N.A., WELLS FARGO BANK, NATIONAL ASSOCIATION, BANK OF CHINA, NEW YORK BRANCH, SCOTIA FINANCI

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 3) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subjec

SC TO-T/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 3) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identi

Biogen Completes Acquisition of Apellis Pharmaceuticals

EX-99.1 Exhibit 99.1    Biogen Completes Acquisition of Apellis Pharmaceuticals Cambridge, Mass. – May 14, 2026 – Biogen Inc. (Nasdaq: BIIB) today announced the successful completion of the acquisition of Apellis Pharmaceuticals, Inc. (Nasdaq: APLS). Apellis, a leader in advancing treatments for serious, complement-driven diseases, is now a wholly owned subsidiary of Biogen. The acquisition adds t

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 3) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subjec

SC TO-T/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 3) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 14, 2026 Biogen Inc. (Exact N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): May 14, 2026 Biogen Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File Number) (IR

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 2) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subjec

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 2) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying stat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 2) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subjec

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 2) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying stat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 1) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subjec

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 1) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying stat

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 1) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subjec

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO (Amendment No. 1) Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying stat

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, 2026 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

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 29, 2026 BIOGEN INC. (Exact

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 29, 2026 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (

Biogen reports strong first quarter 2026 results

Press Release Cambridge, Mass. – April 29, 2026 Biogen reports strong first quarter 2026 results First quarter 2026 total revenue of $2.5 billion, increased 2% year-over-year; GAAP diluted EPS of $2.15, increased 31% year-over-year; Non-GAAP diluted EPS of $3.57, increased 18% year-over-year Growth products1 delivered 12% year-over-year growth demonstrating continued strong commercial execution •L

ARS

2025 ANNUAL REPORTDear Shareholder, Three years ago,we embarked on a journey of transformation with the goal of delivering long-term value for our shareholders with a disciplined and high-conviction late-stage pipeline that could drive both meaningful innovation and sustained growth.

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

Table of Contents 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)) ☒

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

DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒     Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive

Apellis Pharmaceuticals, Inc. 100 Fifth Avenue Waltham, MA 02451 November 1, 2024

EX-99.(d)(4) Exhibit (d)(4) CONFIDENTIAL Apellis Pharmaceuticals, Inc. 100 Fifth Avenue Waltham, MA 02451 November 1, 2024 Biogen Inc. 225 Binney Street Cambridge, MA 02142 Attention: Adam Keeney, Head of Corporate Development Ladies and Gentlemen: 1. In connection with your consideration of a possible business combination or similar transaction (a “Transaction”) involving Apellis Pharmaceuticals,

This announcement is neither an offer to purchase nor a solicitation of an offer to sell Shares (as defined below), and the provisions herein are subject in their entirety to the provisions of the Offer (as defined below). The Offer is made solely by

Form of Summary Exhibit (a)(1)(F) This announcement is neither an offer to purchase nor a solicitation of an offer to sell Shares (as defined below), and the provisions herein are subject in their entirety to the provisions of the Offer (as defined below).

Notice of Guaranteed Delivery Offer to Purchase All Outstanding Shares of Common Stock APELLIS PHARMACEUTICALS, INC. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual righ

Form of Notice of Guaranteed Delivery Exhibit (a)(1)(C) Notice of Guaranteed Delivery for Offer to Purchase All Outstanding Shares of Common Stock of APELLIS PHARMACEUTICALS, INC.

Offer to Purchase All Outstanding Shares of Common Stock APELLIS PHARMACEUTICALS, INC. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual right to receive contingent cash p

Form of Letter to Clients Exhibit (a)(1)(E) Offer to Purchase All Outstanding Shares of Common Stock of APELLIS PHARMACEUTICALS, INC.

This announcement is neither an offer to purchase nor a solicitation of an offer to sell Shares (as defined below), and the provisions herein are subject in their entirety to the provisions of the Offer (as defined below). The Offer is made solely by

Form of Summary Exhibit (a)(1)(F) This announcement is neither an offer to purchase nor a solicitation of an offer to sell Shares (as defined below), and the provisions herein are subject in their entirety to the provisions of the Offer (as defined below).

Table 1: Transaction Valuation

Calculation of Filing Fee Tables Table 1: Transaction Valuation Transaction Valuation Fee Rate Amount of Filing Fee Fees to be Paid 1 $ 5,786,635,909.

AMENDMENT NO. 1 TO CONFIDENTIALITY AGREEMENT

EX-99.(d)(5) Exhibit (d)(5) AMENDMENT NO. 1 TO CONFIDENTIALITY AGREEMENT THIS AMENDMENT NO. 1 TO THE CONFIDENTIALITY AGREEMENT (this “Amendment”) is made as of October 24, 2025 (the “Amendment Date”) between Apellis Pharmaceuticals, Inc. (the “Company”) and Biogen Inc. (“Biogen”). WHEREAS, the Company and Biogen entered into that certain Confidentiality Agreement dated November 1, 2024 (the “Confi

Letter of Transmittal to Tender Shares of Common Stock APELLIS PHARMACEUTICALS, INC. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual right to receive contingent cash pay

Form of Letter of Transmittal Exhibit (a)(1)(B) Letter of Transmittal to Tender Shares of Common Stock of APELLIS PHARMACEUTICALS, INC.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN P

SC TO-T UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) COMMON STOCK, $0.0001 PAR VALUE (Title of Class of S

Offer to Purchase All Outstanding Shares of Common Stock APELLIS PHARMACEUTICALS, INC. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual right to receive contingent cash p

Form of Letter to Brokers Exhibit (a)(1)(D) Offer to Purchase All Outstanding Shares of Common Stock of APELLIS PHARMACEUTICALS, INC.

Offer to Purchase All Outstanding Shares of Common Stock APELLIS PHARMACEUTICALS, INC. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual right to receive contingent cash p

Form of Letter to Brokers Exhibit (a)(1)(D) Offer to Purchase All Outstanding Shares of Common Stock of APELLIS PHARMACEUTICALS, INC.

Offer to Purchase All Outstanding Shares of Common Stock APELLIS PHARMACEUTICALS, INC. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual right to receive contingent cash p

Form of Letter to Clients Exhibit (a)(1)(E) Offer to Purchase All Outstanding Shares of Common Stock of APELLIS PHARMACEUTICALS, INC.

Notice of Guaranteed Delivery Offer to Purchase All Outstanding Shares of Common Stock APELLIS PHARMACEUTICALS, INC. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual righ

Form of Notice of Guaranteed Delivery Exhibit (a)(1)(C) Notice of Guaranteed Delivery for Offer to Purchase All Outstanding Shares of Common Stock of APELLIS PHARMACEUTICALS, INC.

Table 1: Transaction Valuation

Calculation of Filing Fee Tables Table 1: Transaction Valuation Transaction Valuation Fee Rate Amount of Filing Fee Fees to be Paid 1 $ 5,786,635,909.

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN P

SC TO-T UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) COMMON STOCK, $0.0001 PAR VALUE (Title of Class of S

Offer to Purchase All Outstanding Shares of Common Stock Apellis Pharmaceuticals, Inc. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual right to receive contingent cash p

Offer to Purchase Exhibit (a)(1)(A) Offer to Purchase All Outstanding Shares of Common Stock of Apellis Pharmaceuticals, Inc.

Letter of Transmittal to Tender Shares of Common Stock APELLIS PHARMACEUTICALS, INC. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual right to receive contingent cash pay

Form of Letter of Transmittal Exhibit (a)(1)(B) Letter of Transmittal to Tender Shares of Common Stock of APELLIS PHARMACEUTICALS, INC.

Apellis Pharmaceuticals, Inc. 100 Fifth Avenue Waltham, MA 02451 November 1, 2024

EX-99.(d)(4) Exhibit (d)(4) CONFIDENTIAL Apellis Pharmaceuticals, Inc. 100 Fifth Avenue Waltham, MA 02451 November 1, 2024 Biogen Inc. 225 Binney Street Cambridge, MA 02142 Attention: Adam Keeney, Head of Corporate Development Ladies and Gentlemen: 1. In connection with your consideration of a possible business combination or similar transaction (a “Transaction”) involving Apellis Pharmaceuticals,

Offer to Purchase All Outstanding Shares of Common Stock Apellis Pharmaceuticals, Inc. $41.00 per share, net in cash, plus one non-transferable contingent value right for each share, which represents the contractual right to receive contingent cash p

Offer to Purchase Exhibit (a)(1)(A) Offer to Purchase All Outstanding Shares of Common Stock of Apellis Pharmaceuticals, Inc.

AMENDMENT NO. 1 TO CONFIDENTIALITY AGREEMENT

EX-99.(d)(5) Exhibit (d)(5) AMENDMENT NO. 1 TO CONFIDENTIALITY AGREEMENT THIS AMENDMENT NO. 1 TO THE CONFIDENTIALITY AGREEMENT (this “Amendment”) is made as of October 24, 2025 (the “Amendment Date”) between Apellis Pharmaceuticals, Inc. (the “Company”) and Biogen Inc. (“Biogen”). WHEREAS, the Company and Biogen entered into that certain Confidentiality Agreement dated November 1, 2024 (the “Confi

COMBINING OUR STRENGTHS GETTING TO KNOW BIOGEN Confidential - For Internal Integration Planning Purposes Only Important Information The tender offer described in this communication has not yet commenced. This communication is for informational purpos

Exhibit 99.1 Presentation at Apellis Pharmaceuticals, Inc. Employee Meeting on April 7, 2026 COMBINING OUR STRENGTHS GETTING TO KNOW BIOGEN Confidential - For Internal Integration Planning Purposes Only Important Information The tender offer described in this communication has not yet commenced. This communication is for informational purposes only and is neither an offer to purchase nor a solicit

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN P

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying status as offeror, iss

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN P

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying status as offeror, iss

COMBINING OUR STRENGTHS GETTING TO KNOW BIOGEN Confidential - For Internal Integration Planning Purposes Only Important Information The tender offer described in this communication has not yet commenced. This communication is for informational purpos

Exhibit 99.1 Presentation at Apellis Pharmaceuticals, Inc. Employee Meeting on April 7, 2026 COMBINING OUR STRENGTHS GETTING TO KNOW BIOGEN Confidential - For Internal Integration Planning Purposes Only Important Information The tender offer described in this communication has not yet commenced. This communication is for informational purposes only and is neither an offer to purchase nor a solicit

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 6, 2026 Biogen Inc. (Exact

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 6, 2026 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN P

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying status as offeror, iss

The following communication was posted by Biogen Inc. (the “Company”) on LinkedIn on March 31, 2026.

Exhibit 99.1 Exhibit 99.1 LinkedIn: The following communication was posted by Biogen Inc. (the “Company”) on LinkedIn on March 31, 2026. Frame 1: Biogen DEAL NEWS Biogen announces definitive agreement to acquire Apellis Today we announced that we have entered into a definitive agreement to acquire Apellis Pharmaceuticals. We believe this potential acquisition will enhance our growth portfolio in i

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN P

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying status as offeror, iss

The following communication was posted by Biogen Inc. (the “Company”) on LinkedIn on March 31, 2026.

Exhibit 99.1 Exhibit 99.1 LinkedIn: The following communication was posted by Biogen Inc. (the “Company”) on LinkedIn on March 31, 2026. Frame 1: Biogen DEAL NEWS Biogen announces definitive agreement to acquire Apellis Today we announced that we have entered into a definitive agreement to acquire Apellis Pharmaceuticals. We believe this potential acquisition will enhance our growth portfolio in i

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN P

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying status as offeror, iss

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 31, 2026 Biogen Inc. (Exact

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 31, 2026 Biogen Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File Number) (

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 31, 2026 Biogen Inc. (Exact

SC TO-C UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 31, 2026 Biogen Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File N

TENDER AND SUPPORT AGREEMENT

EX-99.1 Exhibit 99.1 TENDER AND SUPPORT AGREEMENT This TENDER AND SUPPORT AGREEMENT (this “Agreement”), dated as of March 31, 2026, is by and among Biogen Inc., a Delaware corporation (“Parent”), Aspen Purchaser Sub, Inc., a Delaware corporation and a wholly owned subsidiary of Parent (“Purchaser”), and each stockholder listed on the signature pages hereto (each, a “Stockholder”). WHEREAS, each St

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 31, 2026 Biogen Inc. (Exact

SC TO-C UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of the Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 31, 2026 Biogen Inc. (Exact Name of Registrant as Specified in its Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File N

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN P

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE TO Tender Offer Statement Pursuant to Section 14(d)(1) or 13(e)(1) of the Securities Exchange Act of 1934 APELLIS PHARMACEUTICALS, INC. (Name of Subject Company) ASPEN PURCHASER SUB, INC. (Offeror) A Wholly Owned Subsidiary of BIOGEN INC. (Parent of Offeror) (Names of Filing Persons (identifying status as offeror, iss

Biogen, Inc.

Exhibit 99.2 31-Mar-2026 Biogen, Inc. (BIIB) Business Update Call CORPORATE PARTICIPANTS Timothy Power Head-Investor Relations, Biogen, Inc. Christopher A. Viehbacher President, Chief Executive Officer & Director, Biogen, Inc. Adam Keeney Executive Vice President & Head-Corporate Development, Biogen, Inc. Robin C. Kramer Executive Vice President & Chief Financial Officer, Biogen, Inc. Alisha A. Al

AGREEMENT AND PLAN OF MERGER by and among PHARMACEUTICALS, INC., ASPEN PURCHASER SUB, BIOGEN INC. Dated as of March 31, 2026

EX-2.1 Exhibit 2.1 Execution Version AGREEMENT AND PLAN OF MERGER by and among APELLIS PHARMACEUTICALS, INC., ASPEN PURCHASER SUB, INC. and BIOGEN INC. Dated as of March 31, 2026 TABLE OF CONTENTS Page Article I The Cash Tender Offer 2 1.1 The Offer 2 1.2 Company Actions 6 Article II The Merger 7   2.1 The Merger; No Vote of Stockholders 7 2.2 Closing 7 2.3 Effective Time of the Merger 8 2.4 Effec

Biogen, Inc.

Exhibit 99.2 31-Mar-2026 Biogen, Inc. (BIIB) Business Update Call CORPORATE PARTICIPANTS Timothy Power Head-Investor Relations, Biogen, Inc. Christopher A. Viehbacher President, Chief Executive Officer & Director, Biogen, Inc. Adam Keeney Executive Vice President & Head-Corporate Development, Biogen, Inc. Robin C. Kramer Executive Vice President & Chief Financial Officer, Biogen, Inc. Alisha A. Al

March 31, 2026 BIOGEN PROPOSED ACQUISITION OF APELLIS INVESTOR WEBCAST

EX-99.3 Exhibit 99.3 March 31, 2026 BIOGEN PROPOSED ACQUISITION OF APELLIS INVESTOR WEBCAST FORWARD-LOOKING STATEMENTS This presentation and discussions during this conference call contain forward-looking statements that are being made pursuant to the provisions of the Private Securities Litigation Reform Act of 1995 (the PSLRA) with the intention of obtaining the benefits of the “Safe Harbor” pro

Biogen to Acquire Apellis, Enhancing the Company’s Growth Portfolio in Immunology and Rare Disease, Bolstering Growth Outlook and Accelerating Expansion into Nephrology

EX-99.2 Exhibit 99.2    Biogen to Acquire Apellis, Enhancing the Company’s Growth Portfolio in Immunology and Rare Disease, Bolstering Growth Outlook and Accelerating Expansion into Nephrology • Acquisition will bring two differentiated commercialized immunology medicines to Biogen with EMPAVELI® FDA-approved in three indications, including two rare kidney diseases, and SYFOVRE® FDA-approved in ge

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 11, 2026 Biogen Inc. (Exact

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 11, 2026 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (

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 11, 2026 Biogen Inc. (Ex

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 11, 2026 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number

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 ☒ ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2025 or ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number: 0-19311 BIOGEN INC. (Exact name of registrant as specified in its cha

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, 2026 BIOGEN INC. (Exa

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, 2026 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

BIOGEN INC.

Exhibit 21 BIOGEN INC. The following is a list of subsidiaries of Biogen Inc. as of December 31, 2025, omitting some subsidiaries which, considered in the aggregate, would not constitute a significant subsidiary. SUBSIDIARY STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION Biogen Foundation Inc. Massachusetts Biogen MA Inc. Massachusetts Biogen Realty Corporation Massachusetts Biogen Re

Biogen reports strong fourth quarter and full year 2025 results and provides full year 2026 financial guidance

Press Release Cambridge, Mass. – February 6, 2026 Biogen reports strong fourth quarter and full year 2025 results and provides full year 2026 financial guidance Fourth quarter 2025 total revenue $2.3 billion; GAAP diluted EPS $(0.33); Non-GAAP diluted EPS $1.99 Full year 2025 total revenue $9.9 billion; GAAP diluted EPS $8.79; Non-GAAP diluted EPS $15.28, exceeding the upper end of our 2025 full y

Policy relating to insider trading.

Exhibit 19.1 Global Insider Trading and Information Policy Purpose 1.1Introduction. U.S. federal and state securities laws prohibit the purchase or sale of a company’s securities by persons who possess Material, Nonpublic Information. These laws also prohibit persons from making Selective Disclosure. Many countries in addition to the U.S. also have laws prohibiting Insider Trading. 1.2Purpose. The

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 13, 2026 Biogen Inc. (Exa

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 13, 2026 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

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 30, 2025 BIOGEN INC. (Exa

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 30, 2025 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

Biogen reports strong third quarter 2025 results and updates full year 2025 guidance

Press Release Cambridge, Mass. – October 30, 2025 Biogen reports strong third quarter 2025 results and updates full year 2025 guidance Third quarter 2025 total revenue of $2.5 billion, increased 3% year-over-year; GAAP diluted EPS of $3.17, increased 19% year-over-year; Non-GAAP diluted EPS of $4.81, increased 18% year-over-year Delivered 67% year-over-year growth across launch products in Alzheim

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, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified 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 14, 2025 Biogen Inc. (Exa

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 14, 2025 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

144

144 0001769608 XXXXXXXX LIVE 0000875045 BIOGEN INC. 000-19311 225 BINNEY STREET CAMBRIDGE MA 02142 7814642000 Singhal Priya Officer Common Fidelity Brokerage Services LLC 900 Salem Street Smithfield RI 02917 517 69045.35 146614598 09/02/2025 NASDAQ Common 09/01/2025 Restricted Stock Vesting Issuer N 517 09/01/2025 Compensation Y 09/02/2025 02/18/2025 /s/ Bradley Camilo, as a duly authorized repres

Biogen reports strong second quarter 2025 results and increases full year 2025 guidance

Press Release Cambridge, Mass. – July 31, 2025 Biogen reports strong second quarter 2025 results and increases full year 2025 guidance Second quarter 2025 total revenue $2.6 billion, increased 7% year-over-year; GAAP diluted EPS $4.33, increased 8% year-over-year; Non-GAAP diluted EPS $5.47, increased 4% year-over-year •GAAP and Non-GAAP diluted EPS includes an approximately ($0.26) impact from $4

Letter regarding employment arrangement of Priya Singhal dated January 3, 2023.

EXHIBIT 10.1 1/3/2023 Priya Singhal [email protected] Dear Priya, I am pleased to offer you a promotion to Executive Vice President (EVP), Head of Drug Development effective January 5th, 2023. This position will report to Biogen’s Chief Executive Officer, Chris Viehbacher. The specific terms of our offer are as follows: Salary: This is a full-time, exempt position and your starting annual s

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 31, 2025 BIOGEN INC. (Exact

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 31, 2025 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I

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, 2025 OR ☐ TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

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): July 7, 2025 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (IR

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 17, 2025 Biogen Inc. (Exact

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 17, 2025 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I

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

DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 14A (Rule 14a-101) INFORMATION REQUIRED IN PROXY STATEMENT SCHEDULE 14A INFORMATION Proxy Statement Pursuant to Section 14(a) of the Securities Exchange Act of 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, fo

Current Report

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT PURSUANT TO SECTIONS 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Date of Report (Date of earliest event reported): May 6, 2025 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I.

Fourth Supplemental Indenture, dated as of May 12, 2025, between the Company and U.S. Bank Trust Company, National Association (as successor to U.S. Bank, National Association), including the forms of Global Notes attached as Exhibit A, Exhibit B and Exhibit C, respectively, thereto

Exhibit 4.2 BIOGEN INC., as Issuer and U.S. Bank Trust Company, National Association, as Trustee Fourth Supplemental Indenture Dated as of May 12, 2025 TABLE OF CONTENTS Page ARTICLE I DEFINITIONS SECTION 2 Section 1.1. Certain Terms Defined in the Indenture 2 Section 1.2. Definitions 2 ARTICLE II FORM AND TERMS OF THE NOTES 6 Section 2.1. Form and Dating 6 Section 2.2. Terms of the Notes 7 Sectio

Underwriting Agreement, dated May 6, 2025, by and among the Company, BofA Securities, Inc., Citigroup Global Markets Inc. and J.P. Morgan Securities LLC, as representatives of the several underwriters named in Schedule I thereto.

EX-1.1 Exhibit 1.1 Execution Version Biogen Inc. 5.050% Senior Notes due 2031 5.750% Senior Notes due 2035 6.450% Senior Notes due 2055 Underwriting Agreement May 6, 2025 BofA Securities, Inc. Citigroup Global Markets Inc. J.P. Morgan Securities LLC As representatives of the several Underwriters named in Schedule I hereto, c/o BofA Securities, Inc.   One Bryant Park   New York, New York 10036-6728

$1,750,000,000 Biogen Inc. $400,000,000 5.050% Senior Notes due 2031 $650,000,000 5.750% Senior Notes due 2035 $700,000,000 6.450% Senior Notes due 2055

Table of Contents Filed pursuant to Rule 424(b)(2) Registration No. 333-286915 Prospectus Supplement (To Prospectus Dated May 1, 2025) $1,750,000,000 Biogen Inc. $400,000,000 5.050% Senior Notes due 2031 $650,000,000 5.750% Senior Notes due 2035 $700,000,000 6.450% Senior Notes due 2055 We are offering $400,000,000 aggregate principal amount of our 5.050% Senior Notes due 2031 (the “notes due 2031

Calculation of Filing Fee Tables (Form Type) Biogen Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities

Exhibit 107 Calculation of Filing Fee Tables 424(b)(2) (Form Type) Biogen Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation or Carry Forward Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Carry Forw

Subject to completion, dated May 6, 2025

Table of Contents Filed pursuant to Rule 424(b)(2) Registration No. 333-286915 The information in this preliminary prospectus supplement and the accompanying prospectus is not complete and may be changed. This preliminary prospectus supplement and the accompanying prospectus are not an offer to sell these securities and we are not soliciting an offer to buy these securities in any jurisdiction whe

$1,750,000,000 Biogen Inc. $400,000,000 5.050% Senior Notes Due 2031 $650,000,000 5.750% Senior Notes Due 2035 $700,000,000 6.450% Senior Notes Due 2055 PRICING TERM SHEET $400,000,000 5.050% Senior Notes Due 2031 Issuer Biogen Inc. Principal Amount

Filed pursuant to Rule 433 Registration No.: 333-286915 Free Writing Prospectus dated May 6, 2025 Relating to Preliminary Prospectus Supplement dated May 6, 2025 (to Prospectus dated May 1, 2025) $1,750,000,000 Biogen Inc. $400,000,000 5.050% Senior Notes Due 2031 $650,000,000 5.750% Senior Notes Due 2035 $700,000,000 6.450% Senior Notes Due 2055 PRICING TERM SHEET $400,000,000 5.050% Senior Notes

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, 2025 BIOGEN INC. (Exact na

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, 2025 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

Form T-1 Statement of Eligibility of Trustee under the Trust Indenture Act of 1939, as amended, of U.S. Bank Trust Company, National Association (as successor-in-interest to U.S. Bank National Association), as trustee**

EX-25.1 Exhibit 25.1 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE ☐ Check if an Application to Determine Eligibility of a Trustee Pursuant to Section 305(b)(2) U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION (Exact name of Trustee as specified in its charter) 91-1821036

Powers of Attorney of Biogen Inc. (included on signature pages to this Registration Statement)**

As filed with the Securities and Exchange Commission on May 1, 2025 No. 333-    UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM S-3 REGISTRATION STATEMENT UNDER THE SECURITIES ACT OF 1933 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 33-0112644 (State or other jurisdiction of incorporation or organization) (I.R.S. Employer Identification N

Biogen reports strong first quarter 2025 results

Press Release Cambridge, Mass. – May 1, 2025 Biogen reports strong first quarter 2025 results First quarter 2025 total revenue $2.4 billion, increased 6% year-over-year; GAAP diluted EPS $1.64; Non-GAAP diluted EPS $3.02 •Product revenue increased 3% at constant currency and 1% at actual currency year-over-year, aided in part by the timing of SPINRAZA shipments •GAAP and Non-GAAP diluted EPS inclu

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

Filing Fee Table**

Exhibit 107 Calculation of Filing Fee Tables FORM S-3 (Form Type) Biogen Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation or Carry Forward Rule Amount Registered (2) Proposed  Maximum  Offering  Price Per  Unit (2)  Maximum  Aggregate  Offering  Price (2)  Fee Rate Amount of Registr

Your Vote Counts! BIOGEN INC. 2025 Annual Meeting Vote by June 16, 2025 11:59 PM ET BIOGEN INC. 225 BINNEY STREET CAMBRIDGE, MA 02142 V69530-P28515 You invested in BIOGEN INC. and it’s time to vote! You have the right to vote on proposals being prese

DEFA14A Your Vote Counts! BIOGEN INC. 2025 Annual Meeting Vote by June 16, 2025 11:59 PM ET BIOGEN INC. 225 BINNEY STREET CAMBRIDGE, MA 02142 V69530-P28515 You invested in BIOGEN INC. and it’s time to vote! You have the right to vote on proposals being presented at the Annual Meeting. This is an important notice regarding the availability of proxy materials for the stockholder meeting to be held o

ARS

2024 ANNUAL REPORTreadouts starting in 2026 with the potential to launch new treatments in 2028.

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

Table of Contents 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)) ☒

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 12, 2025 BIOGEN INC. (Ex

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 12, 2025 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number

Biogen Inc. Supplemental Savings Plan.

EXHIBIT 10.15 BIOGEN INC. SUPPLEMENTAL SAVINGS PLAN (Plan Provisions as in Effect on January 1, 2024) TABLE OF CONTENTS Page ARTICLE 1 INTRODUCTION 1 1.1 Purpose and Effective Date 1 ARTICLE 2 DEFINITIONS 1 2.1 401(k) restoration 1 2.2 Applicable compensation 1 2.3 Base salary 1 2.4 Biogen 1 2.5 Biogen SERP 2 2.6 Board 2 2.7 Change in Control 2 2.8 Code 2 2.9 Committee 2 2.10 Compensation Committe

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 ☒ 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 Commission file number: 0-19311 BIOGEN INC. (Exact name of registrant as specified in its cha

BIOGEN INC.

Exhibit 21 BIOGEN INC. The following is a list of subsidiaries of Biogen Inc. as of December 31, 2024, omitting some subsidiaries which, considered in the aggregate, would not constitute a significant subsidiary. SUBSIDIARY STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION Biogen Foundation Inc. Massachusetts Biogen MA Inc. Massachusetts Biogen Realty Corporation Massachusetts Biogen Re

Biogen reports fourth quarter and full year 2024 results and provides full year 2025 financial guidance

Press Release Cambridge, Mass. – Feb. 12, 2025 Biogen reports fourth quarter and full year 2024 results and provides full year 2025 financial guidance Fourth quarter 2024 total revenue $2.5 billion, 3% growth YoY; GAAP diluted EPS $1.83, 7% growth YoY; Non-GAAP diluted EPS $3.44, 17% growth YoY Full year 2024 total revenue $9.7 billion, 2% decline YoY; GAAP diluted EPS $11.18, 40% growth YoY; Non-

Voluntary Board of Directors Savings Plan.

EXHIBIT 10.14 BIOGEN INC. VOLUNTARY BOARD OF DIRECTORS SAVINGS PLAN (Plan Provisions as in Effect on January 1, 2024) TABLE OF CONTENTS ARTICLE 1 DEFINITIONS...........................................................................................................1 1.1 Purpose and Effective Date..............................................................................................1 ARTICLE

Policy relating to insider trading.

Exhibit 19.1 Global Insider Trading and Information Policy Purpose 1.1Introduction. U.S. federal and state securities laws prohibit the purchase or sale of a company’s securities by persons who possess Material, Nonpublic Information. These laws also prohibit persons from making Selective Disclosure. Many countries in addition to the U.S. also have laws prohibiting Insider Trading. 1.2Purpose. The

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 13, 2025 Biogen Inc. (Exa

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 13, 2025 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

SAGE / Sage Therapeutics, Inc. / BIOGEN INC. - EX-99.1 _ M<_<;E+UO*ES/K&.'W6+'<#S/2O0N2EW+Y8+"B]@PUG_?6]R[0(7#JJI"E:E^ M.EQ

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SAGE / Sage Therapeutics, Inc. / BIOGEN INC. - EX-99.I

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BIIB / Biogen Inc. / VANGUARD GROUP INC Passive Investment

SC 13G/A 1 UnitedStates13GBiogenIncU.txt 240.13d-102 Schedule 13G - 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. Securities and Exchange Commission, Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No. 12)* (Name of Issuer) Biogen Inc (Title of Class of Securities) C

DNLI / Denali Therapeutics Inc. / BIOGEN INC. - SC 13G/A Passive Investment

SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* DENALI THERAPEUTICS INC. (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) 24823R105 (CUSIP Number) October 30, 2024 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the r

BIIB / Biogen Inc. / VANGUARD GROUP INC Passive Investment

SC 13G/A 1 UnitedStates13GBiogenIncU.txt 240.13d-102 Schedule 13G - 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. Securities and Exchange Commission, Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No. 11)* (Name of Issuer) Biogen Inc (Title of Class of Securities) C

Michael McDonnell, Executive Vice President and Chief Financial Officer to Retire in February 2025 Robin Kramer, Chief Accounting Officer, to Succeed Him

Exhibit 99.1 Michael McDonnell, Executive Vice President and Chief Financial Officer to Retire in February 2025 Robin Kramer, Chief Accounting Officer, to Succeed Him CAMBRIDGE, Mass., Oct. 28, 2024 (GLOBE NEWSWIRE) – Biogen Inc. (Nasdaq: BIIB) today announced that Michael McDonnell, Biogen’s Executive Vice President and Chief Financial Officer, plans to retire from the company on February 28, 202

Regulation FD Disclosure

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 28, 2024 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

Biogen reports third quarter 2024 results and raises full year 2024 financial guidance

Press Release Cambridge, Mass. – October 30, 2024 Biogen reports third quarter 2024 results and raises full year 2024 financial guidance Third quarter 2024 revenue $2.5 billion; GAAP diluted EPS $2.66; Non-GAAP diluted EPS $4.08 Continued progress executing across the commercial portfolio •Product launches in Alzheimer's disease, rare disease, and depression each delivered sequential revenue growt

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified 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 30, 2024 BIOGEN INC. (Exa

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 30, 2024 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

Letter regarding employment arrangement of Robin Kramer dated October 28, 2024

Exhibit 10.1 10/28/2024 Robin Kramer [ ] Dear Robin, I am pleased to offer you a promotion to Executive Vice President (EVP), Chief Financial Officer effective February 28, 2025. This position will report to Biogen’s Chief Executive Officer, Chris Viehbacher. The specific terms of our offer are as follows: Salary: This is a full-time, exempt position and your starting annual salary will be $750,00

BIIB / Biogen Inc. / STATE STREET CORP Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. )* BIOGEN INC (Name of Issuer) COMMON STOCK (Title of Class of Securities) 09062X103 (CUSIP Number) September 30, 2024 (Date of Event Which Requires Filing of This Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: ý Rule

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 11, 2024 Biogen 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): September 11, 2024 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Numbe

SGMO / Sangamo Therapeutics, Inc. / BIOGEN INC. - SC 13G/A Passive Investment

SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 2)* SANGAMO THERAPEUTICS, INC. (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) 800677106 (CUSIP Number) August 14, 2024 (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 12, 2024 Biogen Inc. (Exac

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): August 12, 2024 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

Credit Agreement, dated as of August 12, 2024, among Biogen Inc., Bank of America, N.A., as administrative agent, swing line lender and the L/C issuer, and the other lenders party thereto

Exhibit 10.1 EXECUTION VERSION CUSIP Numbers: Deal: 09074KAH0 Revolver: 09074KAJ6 CREDIT AGREEMENT Dated as of August 12, 2024 among BIOGEN INC., as the Borrower, BANK OF AMERICA, N.A., as the Administrative Agent, the Swing Line Lender and the L/C Issuer, CITIBANK, N.A., DEUTSCHE BANK SECURITIES INC., GOLDMAN SACHS BANK USA, JPMORGAN CHASE BANK, N.A., MIZUHO BANK, LTD., MORGAN STANLEY SENIOR FUND

BIIB / Biogen Inc. / BlackRock Inc. Passive Investment

SC 13G/A 1 us09062x1037080724.txt us09062x1037080724.txt SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No: 15) BIOGEN INC - (Name of Issuer) Common Stock - (Title of Class of Securities) 09062X103 - (CUSIP Number) July 31, 2024 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designa

Form of restricted stock award agreement under the Biogen Inc. 2024 Omnibus Equity Plan. Filed as Exhibit 10.4 to our Quarterly Report on Form 10-Q for the quarter ended June 30, 2024.

Exhibit 10.4 RESTRICTED STOCK UNIT AWARD AGREEMENT GRANTED UNDER BIOGEN INC. 2024 OMNIBUS EQUITY PLAN 1.Grant of Restricted Stock Units Pursuant to the Biogen Inc. 2024 Omnibus Equity Plan (as it may be amended from time to time, the “Plan”), Biogen Inc. (the “Company”) hereby grants to you, an employee or service provider of the Company or one of its Affiliates (the “Participant”), on each of the

Form of performance share award agreement under the Biogen Inc. 2024 Omnibus Equity Plan.

Exhibit 10.3 PERFORMANCE STOCK UNITS AWARD AGREEMENT GRANTED UNDER BIOGEN INC. 2024 OMNIBUS EQUITY PLAN 1.Grant of Performance Stock Units Pursuant to the Biogen Inc. 2024 Omnibus Equity Plan (as it may be amended from time to time, the “Plan”), Biogen Inc. (the “Company”) hereby grants to you, an employee or service provider of the Company or one of its Affiliates (the “Participant”), on each of

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 1, 2024 BIOGEN INC. (Exact

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 1, 2024 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

Biogen reports strong second quarter 2024 results and raises full year 2024 financial guidance; Second quarter 2024 total revenue of $2.5 billion, GAAP diluted EPS of $4.00 and Non-GAAP diluted EPS of $5.28

EX-99.1 2 exhibit991-q22024pressrele.htm EX-99.1 Press Release Cambridge, Mass. – Aug. 1, 2024 Biogen reports strong second quarter 2024 results and raises full year 2024 financial guidance; Second quarter 2024 total revenue of $2.5 billion, GAAP diluted EPS of $4.00 and Non-GAAP diluted EPS of $5.28 Second quarter total revenue was flat at actual currency and up 1% at constant currency, with GAAP

Form of restricted stock unit award agreement for non-employee Director's under the Biogen Inc. 2024 Omnibus Equity Plan.

Exhibit 10.5 NON-EMPLOYEE DIRECTOR RESTRICTED STOCK UNIT AWARD AGREEMENT GRANTED UNDER BIOGEN INC. 2024 OMNIBUS EQUITY PLAN 1.Grant of Restricted Stock Units Pursuant to the Biogen Inc. 2024 Omnibus Equity Plan (as it may be amended from time to time, the “Plan”), Biogen Inc. (the “Company”) hereby grants to you, a non-employee director of the Company or one of its Affiliates (the “Participant”),

Certificate of Amendment of Biogen Inc.’s Amended and Restated Certificate of Incorporation, as amended.

Exhibit 3.1 CERTIFICATE OF AMENDMENT TO THE CERTIFICATE OF INCORPORATION OF BIOGEN INC. Pursuant to Section 242 of the General Corporation Law of the State of Delaware Biogen Inc. (hereinafter referred to as the “Corporation”), a corporation duly organized and existing under the Delaware General Corporation Law (the “DGCL”), does hereby certify as follows: FIRST: That resolutions were duly adopted

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 20, 2024 Biogen Inc. (Exact

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 20, 2024 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I

Filing Fee Table.

Exhibit 107 Filing Fee Table Form S-8 (Form Type) Biogen Inc. (Exact Name of Registrant as Specified in its Charter) Table 1: Newly Registered Securities Security Type Security Class Title Fee Calculation Rule Amount Registered(1) Proposed Maximum Offering Price Per Share Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Equity Common stock, par value $0.0005 per share, reserved

As filed with the Securities and Exchange Commission on June 20, 2024

As filed with the Securities and Exchange Commission on June 20, 2024 Registration No.

Certificate of Amendment of Biogen Inc.’s Amended and Restated Certificate of Incorporation, as amended.

Exhibit 4.4 CERTIFICATE OF AMENDMENT TO THE CERTIFICATE OF INCORPORATION OF BIOGEN INC. Pursuant to Section 242 of the General Corporation Law of the State of Delaware Biogen Inc. (hereinafter referred to as the “Corporation”), a corporation duly organized and existing under the Delaware General Corporation Law (the “DGCL”), does hereby certify as follows: FIRST: That resolutions were duly adopted

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1) Filed by the Registrant ☒      Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934

Table of Contents 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)) ☒

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

Biogen reports first quarter 2024 GAAP EPS growth of 1% and Non-GAAP EPS growth of 8%

Press Release Cambridge, Mass. – Apr. 24, 2024 Biogen reports first quarter 2024 GAAP EPS growth of 1% and Non-GAAP EPS growth of 8% First quarter revenue $2.3 billion; GAAP diluted EPS $2.70; Non-GAAP diluted EPS $3.67 First quarter product revenue decreased 3% and total revenue decreased 7%, while GAAP operating income grew 10% and Non-GAAP operating income grew 24%; meaningful improvement in bo

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 24, 2024 BIOGEN INC. (Exact

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 24, 2024 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (

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

Table of Contents 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)) ☐

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 ☒ 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 Commission file number: 0-19311 BIOGEN INC. (Exact name of registrant as specified in its cha

Description of Securities.

Exhibit 4.6 DESCRIPTION OF THE REGISTRANT’S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 As of December 31, 2023, Biogen Inc. (the “Company”) has one class of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended (the “Exchange Act”): our Common Stock. Description of Common Stock The following description of our Common Stoc

, Samsung BioLogics Co., Ltd. and Samsung Bioepis Co., Ltd, dated April 20, 2020.

Execution Version JVA TERMINATION AGREEMENT THIS JVA TERMINATION AGREEMENT (this “Agreement”) is entered into this 20th day of April, 2022, by and between: (1)Biogen Therapeutics Inc.

etter regarding employment arrangement of Rachid Izzar dated August

July 29, 2019 Dear Rachid, I am pleased to extend you this offer of employment to join Biogen with the job title of President, Intercontinental.

Filed as Exhibit 97.1 to our Annual Report on Form 10-K for the year ended December 31, 2023.

FINAL BIOGEN INC. POLICY FOR RECOUPMENT OF INCENTIVE COMPENSATION 1.Introduction In accordance with Section 10D of the Securities Exchange Act of 1934, as amended (the Exchange Act”), and the regulations promulgated thereunder, the Board of Directors (the “Board”) of Biogen Inc.(the “Company”) has adopted a policy (the “Policy”) providing for the Company’s recoupment of certain incentive-based com

BIOGEN INC.

Exhibit 21 BIOGEN INC. The following is a list of subsidiaries of Biogen Inc. as of December 31, 2023, omitting some subsidiaries which, considered in the aggregate, would not constitute a significant subsidiary. SUBSIDIARY STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION Biogen Foundation Inc. Massachusetts Biogen MA Inc. Massachusetts Biogen Realty Corporation Massachusetts Biogen Re

Letter amending employment arrangement of Susan Alexander dated February 28, 2020.

February 28, 2020 VIA ELECTRONIC DELIVERY Susan Alexander [*] Dear Susan: Reference is made to your offer letter dated December 13, 2005 (“Offer Letter”), between you and Biogen Idec (now Biogen Inc.

Financial Statements and Exhibits, Results of Operations and Financial Condition

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): February 13, 2024 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number

Biogen reports fourth quarter and full year 2023 results and expects return to Non-GAAP EPS growth in 2024

Press Release Cambridge, Mass. – Feb. 13, 2024 Biogen reports fourth quarter and full year 2023 results and expects return to Non-GAAP EPS growth in 2024 Fourth quarter 2023 revenue $2.4 billion; GAAP diluted EPS $1.71; Non-GAAP diluted EPS $2.95 •GAAP and Non-GAAP diluted EPS negatively impacted by $0.35 related to previously disclosed closeout costs for ADUHELM Full year 2023 revenue $9.8 billio

DNLI / Denali Therapeutics Inc. / BIOGEN INC. - SC 13G/A Passive Investment

SC 13G/A 1 d589107dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* DENALI THERAPEUTICS INC. (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) 24823R105 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of this Statement) Check the app

SGMO / Sangamo Therapeutics, Inc. / BIOGEN INC. - SC 13G/A Passive Investment

SC 13G/A 1 d662582dsc13ga.htm SC 13G/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 1)* SANGAMO THERAPEUTICS, INC. (Name of Issuer) Common Stock, $0.01 par value (Title of Class of Securities) 800677106 (CUSIP Number) December 31, 2023 (Date of Event Which Requires Filing of this Statement) Check the a

BIIB / Biogen Inc. / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SC 13G/A 1 tv0011-biogeninc.htm SCHEDULE 13G/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 10)* Name of issuer: Biogen Inc Title of Class of Securities: Common Stock CUSIP Number: 09062X103 Date of Event Which Requires Filing of this Statement: January 31, 2024 Check the appropriate box to designate the rule pursu

BIIB / Biogen Inc. / PRIMECAP MANAGEMENT CO/CA/ - PRIMECAP MANAGEMENT CO/CA/ Passive Investment

SC 13G/A 1 biiba2621224.htm PRIMECAP MANAGEMENT CO/CA/ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 26)* Biogen Inc. (Name of Issuer) COM (Title of Class of Securities) 09062X103 (CUSIP Number) December 31, 2023 (Date of Event which Requires Filing of this Statement) Check the appropriate box to design

BIIB / Biogen Inc. / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 9)* Name of issuer: Biogen Inc Title of Class of Securities: Common Stock CUSIP Number: 09062X103 Date of Event Which Requires Filing of this Statement: December 29, 2023 Check the appropriate box to designate the rule pursuant to which this Schedule is filed: ☒ Rule 13d

BIIB / Biogen Inc. / BlackRock Inc. Passive Investment

SC 13G/A 1 us09062x1037012424.txt us09062x1037012424.txt SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No: 14) BIOGEN INC - (Name of Issuer) Common Stock - (Title of Class of Securities) 09062X103 - (CUSIP Number) December 31, 2023 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to des

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 6, 2023 Biogen Inc. (Exa

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 6, 2023 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

Fifth Amended and Restated Bylaws. Filed as Exhibit 3.1 to our Current Report on Form 8-K filed on December 12, 2023.

Exhibit 3.1 FIFTH AMENDED AND RESTATED BYLAWS OF BIOGEN INC. TABLE OF CONTENTS Page ARTICLE 1 Offices 1 1.1 Registered Office 1 1.2 Other Offices 1 ARTICLE 2 Meeting of Stockholders 1 2.1 Place of Meeting 1 2.2 Annual Meeting 1 2.3 Special Meetings Called by Directors or Officers 4 2.3A Special Meetings Called by Stockholders 4 2.4 Notice of Meetings 7 2.5 List of Stockholders 8 2.6 Organization a

Marked Fifth Amended and Restated Bylaws of Biogen Inc.

Exhibit 3.2 FOURTHFIFTH AMENDED AND RESTATED BYLAWS OF BIOGEN INC. TABLE OF CONTENTS Page ARTICLE 1 Offices 1 1.1 Registered Office 1 1.2 Other Offices 1 ARTICLE 2 Meeting of Stockholders 1 2.1 Place of Meeting 1 2.2 Annual Meeting 1 2.3 Special Meetings Called by Directors or Officers 4 2.3A Special Meetings Called by Stockholders 5 2.4 Notice of Meetings 68 2.5 List of Stockholders 78 2.6 Organi

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): November 6, 2023 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified 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): November 8, 2023 BIOGEN INC. (Exa

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 OR 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): November 8, 2023 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

Biogen reports third quarter 2023 results and updates full year 2023 guidance

Press Release Cambridge, Mass. – Nov. 8, 2023 Biogen reports third quarter 2023 results and updates full year 2023 guidance Third quarter revenue $2,530 million; GAAP diluted EPS $(0.47); Non-GAAP diluted EPS $4.36 Poised for leadership in Alzheimer's disease with ongoing LEQEMBI launch and development of tau-directed ASO (BIIB080) •New data support potential for subcutaneous formulation of LEQEMB

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A 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 26, 2023 Biogen Inc. (Exac

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K/A 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 26, 2023 Biogen Inc. (Exact name of Registrant as specified in its charter) Delaware 0-19311 33-0112644 (State of Incorporation) (Commission File Number) (I.R.S. Employer Ident

RETA / Reata Pharmaceuticals Inc - Class A / BIOGEN INC. - SC 13D/A Activist Investment

SC 13D/A UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D/A (Amendment No. 1)* Under the Securities Exchange Act of 1934 REATA PHARMACEUTICALS, INC. (Name of Issuer) Class A Common Stock, par value $0.001 per share (Title of Class of Securities) 75615P 103 (CUSIP Number) Biogen Inc. 225 Binney Street Cambridge, Massachusetts 02142 (617) 679-2000 Attention: Wende

Biogen Completes Acquisition of Reata Pharmaceuticals

EX-99.1 Exhibit 99.1 Biogen Completes Acquisition of Reata Pharmaceuticals • Reata acquisition bolsters Biogen’s rare disease portfolio with the addition of SKYCLARYS® (omaveloxolone), the first and only FDA approved treatment for Friedreich’s ataxia in the U.S. CAMBRIDGE, Mass., Sept. 26, 2023 (GLOBE NEWSWIRE) – Biogen Inc. (Nasdaq: BIIB) – has completed the acquisition of Reata Pharmaceuticals,

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 26, 2023 BIOGEN 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): September 26, 2023 BIOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File Number)

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 28, 2023 BIOGEN INC. (Exa

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 28, 2023 BIOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File Number) (IR

Credit Agreement, dated as of August 28, 2023, among Biogen Inc., JPMorgan Chase Bank N.S., as administrative agent and the other lenders party thereto. Filed as Exhibit 10.1 to our Current Report on Form 8-K filed on September 1, 2023.

Exhibit 10.1 EXECUTION VERSION TERM LOAN CREDIT AGREEMENT Dated as of August 28, 2023 among BIOGEN INC., as the Borrower, JPMORGAN CHASE BANK, N.A., as Administrative Agent and The Other Lenders Party Hereto JPMORGAN CHASE BANK, N.A., BANK OF AMERICA, N.A., BANK OF CHINA, NEW YORK BRANCH, CITIBANK, N.A., DEUTSCHE BANK SECURITIES INC., MIZUHO BANK, LTD., MORGAN STANLEY SENIOR FUNDING, INC., U.S. BA

RETA / Reata Pharmaceuticals Inc - Class A / BIOGEN INC. - SC 13D Activist Investment

SC 13D UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13D Under the Securities Exchange Act of 1934 REATA PHARMACEUTICALS, INC. (Name of Issuer) Class A Common Stock, par value $0.001 per share (Title of Class of Securities) 75615P 103 (CUSIP Number) Biogen Inc. 225 Binney Street Cambridge, Massachusetts 02142 (617) 679-2000 Attention: Wendell Taylor, Assistant Se

Agreement and Plan of Merger by and among Reata Pharmaceuticals, Inc., Biogen Inc. and River Acquisition, Inc. dated as of July 28, 2023. Filed as Exhibit 2.1 to our current report on Form 8-K filed July 31, 2023.

EX-2.1 Exhibit 2.1 Execution Version AGREEMENT AND PLAN OF MERGER by and among REATA PHARMACEUTICALS, INC., BIOGEN INC. and RIVER ACQUISITION, INC. Dated as of July 28, 2023 TABLE OF CONTENTS Page ARTICLE I DEFINITIONS & INTERPRETATIONS 1.1 Certain Definitions 2 1.2 Additional Definitions 13 1.3 Certain Interpretations 15 ARTICLE II THE MERGER 2.1 The Merger 16 2.2 The Effective Time 16 2.3 The Cl

Fourth Amended and Restated Bylaws of Biogen Inc.

Exhibit 3.1 FOURTH AMENDED AND RESTATED BYLAWS OF BIOGEN INC. TABLE OF CONTENTS Page ARTICLE 1 Offices 1 1.1 Registered Office 1 1.2 Other Offices 1 ARTICLE 2 Meeting of Stockholders 1 2.1 Place of Meeting 1 2.2 Annual Meeting 1 2.3 Special Meetings Called by Directors or Officers 4 2.3A Special Meetings Called by Stockholders 4 2.4 Notice of Meetings 6 2.5 List of Stockholders 7 2.6 Organization

Voting and Support Agreement, dated as of July 28, 2023, by and among Biogen Inc., River Acquisition, Inc. and each stockholder of Reata Pharmaceuticals, Inc., set forth on Exhibit A thereto

EX-10.3 Exhibit 10.3 Execution Version VOTING AND SUPPORT AGREEMENT THIS VOTING AND SUPPORT AGREEMENT is dated as of July 28, 2023 (this “Agreement”), by and among each stockholder of Reata Pharmaceuticals, Inc., a Delaware corporation (the “Company”), set forth on Exhibit A hereto (each a “Holder” and collectively the “Holders”), Biogen Inc., a Delaware corporation (“Parent”), and River Acquisiti

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 28, 2023 BIOGEN INC. (Exact

DEFA14A 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 28, 2023 BIOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File Numbe

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 28, 2023 BIOGEN INC. (Exact

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 28, 2023 BIOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File Number) (IRS

Voting and Support Agreement, dated as of July 28, 2023, by and among Biogen Inc., River Acquisition, Inc. and each stockholder of Reata Pharmaceuticals, Inc., set forth on Exhibit A thereto

EX-10.1 Exhibit 10.1 Execution Version VOTING AND SUPPORT AGREEMENT THIS VOTING AND SUPPORT AGREEMENT is dated as of July 28, 2023 (this “Agreement”), by and among each stockholder of Reata Pharmaceuticals, Inc., a Delaware corporation (the “Company”), set forth on Exhibit A hereto (each a “Holder” and collectively the “Holders”), Biogen Inc., a Delaware corporation (“Parent”), and River Acquisiti

Voting and Support Agreement, dated as of July 28, 2023, by and among Biogen Inc., River Acquisition, Inc. and each stockholder of Reata Pharmaceuticals, Inc., set forth on Exhibit A thereto

EX-10.2 Exhibit 10.2 Execution Version VOTING AND SUPPORT AGREEMENT THIS VOTING AND SUPPORT AGREEMENT is dated as of July 28, 2023 (this “Agreement”), by and among each stockholder of Reata Pharmaceuticals, Inc., a Delaware corporation (the “Company”), set forth on Exhibit A hereto (each a “Holder” and collectively the “Holders”), Biogen Inc., a Delaware corporation (“Parent”), and River Acquisiti

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 28, 2023 BIOGEN INC. (Exact

DEFA14A 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 28, 2023 BIOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File Numbe

Forward-looking statements This presentation contains forward-looking statements, relating to: our strategy and plans; potential of, and expectations for, our commercial business and pipeline programs; capital allocation and investment strategy; clin

EX-99.2 Exhibit 99.2 Proposed Acquisition of Reata Pharmaceuticals, Inc. Investor Webcast July 28, 2023 Forward-looking statements This presentation contains forward-looking statements, relating to: our strategy and plans; potential of, and expectations for, our commercial business and pipeline programs; capital allocation and investment strategy; clinical development programs, clinical trials, an

Biogen to Acquire Reata Pharmaceuticals SKYCLARYS® recently approved in US as the only treatment indicated for patients with Friedreich’s ataxia Proposed acquisition represents meaningful step forward in Biogen’s strategy for sustainable growth, addi

Exhibit 99.1 CONFIDENTIAL PLANNING MATERIALS NOT FOR EXTERNAL DISTRIBUTION DRAFT SUBJECT TO FURTHER REVIEW July 28, 2023 Project River: Announcement Press Release Biogen to Acquire Reata Pharmaceuticals SKYCLARYS® recently approved in US as the only treatment indicated for patients with Friedreich’s ataxia Proposed acquisition represents meaningful step forward in Biogen’s strategy for sustainable

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): July 28, 2023 BIOGEN INC. (Exact Name of Registrant as Specified in Charter) Delaware 0-19311 33-0112644 (State or Other Jurisdiction of Incorporation) (Commission File Number) (IRS

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

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 25, 2023 BIOGEN INC. (Exact

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 25, 2023 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I

Biogen reports second quarter 2023 results and reaffirms full year 2023 guidance; LEQEMBI launched in the U.S.

Press Release Cambridge, Mass. – July 25, 2023 Biogen reports second quarter 2023 results and reaffirms full year 2023 guidance; LEQEMBI launched in the U.S. Second quarter revenue $2,456 million; GAAP diluted EPS $4.07; Non-GAAP diluted EPS $4.02 Poised for leadership in Alzheimer's disease with launch of LEQEMBI in the U.S. New "Fit for Growth" program expected to generate approximately $1 billi

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 26, 2023 Biogen Inc. (Exact

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 26, 2023 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I

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

DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Pro

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1)

DEFR14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 (Amendment No. 1) Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)

UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934

DEFA14A UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.C. 20549 SCHEDULE 14A PROXY STATEMENT PURSUANT TO SECTION 14(A) OF THE SECURITIES EXCHANGE ACT OF 1934 Filed by the Registrant ☒ Filed by a Party other than the Registrant ☐ Check the appropriate box: ☐ Preliminary Proxy Statement ☐ Confidential, for Use of the Commission Only (as permitted by Rule 14a-6(e)(2)) ☐ Definitive Pro

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 Biogen Inc. (Exact na

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 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

ARS

ANNUAL REPORT 2022Safe harbor This letter contains forward-looking statements relating to: our strategy and plans; potential of, and expectations for, our commercial business and pipeline programs; capital allocation and investment strategy; clinical development programs, clinical trials, and data readouts and presentations; regulatory discussions, submissions, filings and approvals; the potential

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

DEFA14A Table of Contents UNITED STATES SECURITIES AND EXCHANGE COMMISSION WASHINGTON, D.

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

Table of Contents 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)) ☒ Defi

etter regarding employment arrangement of Nicole Murphy dated January 28, 2022. Filed as Exhi

Exhibit 10.3 1/28/2022 Nicole Murphy [email protected] Dear Nicole, I am pleased to offer you a promotion to Executive Vice President (EVP), Head of Pharmaceutical Operations & Technology effective February 1, 2022. This position will report to Biogen's Chief Executive Officer, Michel Vounatsos. The effective date of this new position will be arranged following your formal acceptance of thi

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, 2023 BIOGEN INC. (Exact

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, 2023 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (

Letter regarding employment arrangement of Ginger Gregory dated June 9, 2017.

Exhibit 10.2 CERTAIN INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY [***], HAS BEEN OMITTED BECAUSE IT IS BOTH NOT MATERIAL AND IS THE TYPE THAT BIOGEN INC. TREATS AS PRIVATE OR CONFIDENTIAL. June 9, 2017 Ginger Gregory [***] Dear Ginger, I am pleased to extend you this offer of employment to join Biogen with the job title of EVP, Chief Human Resources Officer. This position will report to Mich

Strong progress toward three potential launches in 2023; Company reports first quarter 2023 results and reaffirms full year 2023 guidance

Strong progress toward three potential launches in 2023; Company reports first quarter 2023 results and reaffirms full year 2023 guidance First quarter 2023 financial results •First quarter revenue $2,463 million; GAAP diluted EPS $2.

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

Fourth Amended and Restated Bylaws of Biogen Inc.

EX-3.1 Exhibit 3.1 FOURTH AMENDED AND RESTATED BYLAWS OF BIOGEN INC. TABLE OF CONTENTS Page ARTICLE 1 Offices 1 1.1 Registered Office 1 1.2 Other Offices 1 ARTICLE 2 Meeting of Stockholders 1 2.1 Place of Meeting 1 2.2 Annual Meeting 1 2.3 Special Meetings Called by Directors or Officers 4 2.3A Special Meetings Called by Stockholders 4 2.4 Notice of Meetings 6 2.5 List of Stockholders 7 2.6 Organi

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 12, 2023 Biogen Inc. (Exact

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 12, 2023 Biogen Inc. (Exact name of Registrant as specified in its charter) Delaware 0-19311 33-0112644 (State of Incorporation) (Commission File Number) (I.R.S. Employer Identi

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 5, 2023 Biogen Inc. (Exact

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM 8-K CURRENT REPORT Pursuant to Section 13 or 15(d) of The Securities Exchange Act of 1934 Date of Report (Date of earliest event reported): March 5, 2023 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (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 15, 2023 BIOGEN INC. (Ex

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 15, 2023 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number

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 ☒ 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 Commission file number: 0-19311 BIOGEN INC. (Exact name of registrant as specified in its cha

Biogen advances significant potential growth drivers; Company reports full year 2022 results and provides full year 2023 guidance

Biogen advances significant potential growth drivers; Company reports full year 2022 results and provides full year 2023 guidance Full year 2022 revenue and Non-GAAP EPS exceed guidance •Fourth quarter revenue $2,544 million; GAAP diluted EPS $3.

Amended and Restated Collaboration Agreement, dated October 22, 2017, between Biogen MA Inc. and Eisai Co., LTD. Filed as Exhibit 10.45 to our Annual Report on Form 10-K for the year ended December 31, 2022.

EXHIBIT 10.45 CERTAIN INFORMATION CONTAINED IN THIS DOCUMENT, MARKED BY [***], HAS BEEN OMITTED BECAUSE IT IS BOTH NOT MATERIAL AND IS THE TYPE THAT BIOGEN INC. TREATS AS PRIVATE OR CONFIDENTIAL. Execution Version AMENDED AND RESTATED COLLABORATION AGREEMENT dated as of October 22, 2017 between BIOGEN MA INC. and EISAI CO., LTD. 1325396161 TABLE OF CONTENTS Page ARTICLE 1 DEFINITIONS 1 ARTICLE 2 C

BIOGEN INC.

Exhibit 21 BIOGEN INC. The following is a list of subsidiaries of Biogen Inc. as of December 31, 2022, omitting some subsidiaries which, considered in the aggregate, would not constitute a significant subsidiary. SUBSIDIARY STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION Biogen Foundation Inc. Massachusetts Biogen MA Inc. Massachusetts Biogen Realty Corporation Massachusetts Biogen Re

Amendment to Credit Agreement, dated as of February 7, 2023, by and among Biogen Inc., Bank of America, N.A., as administrative agent, swing line lender and the L&C issuer, and the other lenders party thereto.

EXHIBIT 10.3 EXECUTION VERSION AMENDMENT TO CREDIT AGREEMENT THIS AMENDMENT TO CREDIT AGREEMENT (this “Agreement”), dated as of February 7, 2023 (the “Amendment Effective Date”), is entered into among BIOGEN INC., a Delaware corporation (the “Borrower”), each Lender party hereto, and BANK OF AMERICA, N.A., as the Administrative Agent, the Swing Line Lender, and the L/C Issuer. All capitalized term

First Amendment to Amended and Restated Collaboration Agreement, dated March 13, 2022, between Biogen MA Inc. and Eisai Co., LTD. Filed as Exhibit 10.46 to our Annual Report on Form 10-K for the year ended December 31, 2022.

EXHIBIT 10.46 FIRST AMENDMENT TO AMENDED AND RESTATED COLLABORATION AGREEMENT This First Amendment to the Amended and Restated Collaboration Agreement (this “Amendment”) is entered into as of March 13, 2022 (the “Amendment Effective Date”), by and between Eisai Co., Ltd., a Japanese corporation, with a place of business at 4-6-10, Koishikawa, Bunkyo-ku Tokyo 112-8088, Japan (“Eisai”) and Biogen MA

Form of nonqualified stock option award agreement under Biogen Inc. 2017 Omnibus Equity Plan. Filed as Exhibit 10.20 to our Annual Report on Form 10-K for the year ended December 31, 2022.

EXHIBIT 10.20 NONQUALIFIED STOCK OPTION AWARD AGREEMENT GRANTED UNDER BIOGEN INC. 2017 OMNIBUS EQUITY PLAN 1.Grant of Options Pursuant to the Biogen Inc. 2017 Omnibus Equity Plan (as it may be amended, modified, or supplemented from time to time, the “Plan”), Biogen Inc. (the “Company") hereby grants an employee of the Company or its Affiliates (the “Participant”), on (the “Grant Date”), a nonqual

BIIB / Biogen Inc / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SC 13G/A 1 tv0413-biogeninc.htm SCHEDULE 13G/A SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 8)* Name of issuer: Biogen Inc. Title of Class of Securities: Common Stock CUSIP Number: 09062X103 Date of Event Which Requires Filing of this Statement: December 30, 2022 Check the appropriate box to designate the rule purs

BIIB / Biogen Inc / PRIMECAP MANAGEMENT CO/CA/ - PRIMECAP MANAGEMENT CO/CA/ Passive Investment

SC 13G/A 1 biiba2520923.htm PRIMECAP MANAGEMENT CO/CA/ UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 25)* Biogen Inc. (Name of Issuer) COM (Title of Class of Securities) 09062X103 (CUSIP Number) December 31, 2022 (Date of Event which Requires Filing of this Statement) Check the appropriate box to design

BIIB / Biogen Inc / BlackRock Inc. Passive Investment

SC 13G/A 1 us09062x1037012423.txt us09062x1037012423.txt SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No: 13) BIOGEN INC - (Name of Issuer) Common Stock - (Title of Class of Securities) 09062X103 - (CUSIP Number) December 31, 2022 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to des

Employment Agreement, dated November 10, 2022, by and between Biogen Inc. and Christopher A. Viehbacher. Filed as Exhibit 10.1 to our Current Report on Form 8-K filed on November 10, 2022.

Exhibit 10.1 EXECUTION VERSION EMPLOYMENT AGREEMENT EMPLOYMENT AGREEMENT (?Agreement?) dated November 10, 2022 between BIOGEN INC., a Delaware corporation (the ?Company?), and Christopher A. Viehbacher (the ?Executive?). WHEREAS, the Company wishes to employ the Executive to serve as the Company?s President and Chief Executive Officer, and the Executive is willing to be employed and serve in such

Biogen Names Christopher Viehbacher President and Chief Executive Officer Distinguished Industry Leader Brings Extensive International Experience in Large Pharmaceutical and Entrepreneurial Biotech Companies

Exhibit 99.1 Biogen Names Christopher Viehbacher President and Chief Executive Officer Distinguished Industry Leader Brings Extensive International Experience in Large Pharmaceutical and Entrepreneurial Biotech Companies CAMBRIDGE, Mass., November 10, 2022: Biogen Inc. (NASDAQ: BIIB) today announced that its Board of Directors has appointed Christopher A. Viehbacher as President and Chief Executiv

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): November 10, 2022 Biogen Inc. (Exact name of Registrant as specified in its charter) Delaware 0-19311 33-0112644 (State of Incorporation) (Commission File Number) (I.R.S. Employer Ide

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): October 25, 2022 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in

Biogen Reports Third Quarter 2022 Results

EX-99.1 2 exhibit991-q32022pressrele.htm EX-99.1 Biogen Reports Third Quarter 2022 Results •Third quarter revenue $2,508 million; GAAP diluted EPS $7.84; Non-GAAP diluted EPS $4.77 •Phase 3 study of lecanemab in early Alzheimer’s disease met the primary endpoint and all key secondary endpoints with highly statistically significant results •New data support the potential for zuranolone as a novel t

Prior Guidance Updated Guidance Total revenue $9.7 to $10.0 billion $9.9 to $10.1 billion Non-GAAP diluted EPS $14.25 to $16.00 $15.25 to $16.75

Biogen Reports Second Quarter 2022 Results ?Second quarter revenue $2,589 million; GAAP diluted EPS $7.

Financial Statements and Exhibits, Results of Operations and Financial Condition

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): July 20, 2022 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commis

Prior Guidance Updated Guidance Total revenue $9.7 to $10.0 billion $9.9 to $10.1 billion Non-GAAP diluted EPS $14.25 to $16.00 $15.25 to $16.75

Biogen Reports Second Quarter 2022 Results ?Second quarter revenue $2,589 million; GAAP diluted EPS $7.

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): July 20, 2022 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

As filed with the Securities and Exchange Commission on July 6, 2022

As filed with the Securities and Exchange Commission on July 6, 2022 Registration No.

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

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 15, 2022 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (I

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 State

Biogen Inc. Offer to Exchange up to $700,731,000 of our outstanding unregistered 3.250% Senior Notes due 2051 for a like principal amount of 3.250% Senior Notes due 2051 that have been registered under the Securities Act of 1933, as amended

Table of Contents Filed Pursuant to Rule 424(b)(3) Registration No. 333-265023 PROSPECTUS Biogen Inc. Offer to Exchange up to $700,731,000 of our outstanding unregistered 3.250% Senior Notes due 2051 for a like principal amount of 3.250% Senior Notes due 2051 that have been registered under the Securities Act of 1933, as amended Biogen Inc. is offering $700,731,000 aggregate principal amount of ne

Biogen Inc. 225 Binney Street Cambridge, Massachusetts 02142

Biogen Inc. 225 Binney Street Cambridge, Massachusetts 02142 May 24, 2022 VIA EDGAR Securities and Exchange Commission Division of Corporation Finance 100 F Street, N.E. Washington, D.C. 20549 Re: Biogen Inc. Registration Statement on Form S-4 File No. 333-265023 Request for Acceleration Ladies and Gentlemen: Pursuant to Rule 461 under the Securities Act of 1933, as amended, Biogen Inc. hereby req

LETTER

United States securities and exchange commission logo May 23, 2022 Susan H. Alexander, Esq. Executive Vice President and Chief Legal Officer Biogen Inc. 225 Binney Street Cambridge, Massachusetts 02142 Re: Biogen Inc. Registration Statement on Form S-4 Filed May 17, 2022 File No. 333-265023 Dear Ms. Alexander: This is to advise you that we have not reviewed and will not review your registration st

As filed with the Securities and Exchange Commission on May 17, 2022

Table of Contents As filed with the Securities and Exchange Commission on May 17, 2022 Registration No.

Filing Fee Table, filed herewith.

EXHIBIT 107 Newly Registered and Carry Forward Securities Security Type Security Class Title Fee Calculation or Carry Forward Rule Amount Registered Proposed Maximum Offering Price Per Unit Maximum Aggregate Offering Price Fee Rate Amount of Registration Fee Carry Forward Form Type Carry Forward File Number Carry Forward Initial effective date Filing Fee Previously Paid In Connection with Unsold Securities to be Carried Forward Newly Registered Securities Fees to Be Paid Debt 3.

Form of Letter of Transmittal, filed herewith.

Exhibit 99.1 LETTER OF TRANSMITTAL FOR BIOGEN INC. OFFER TO EXCHANGE ANY AND ALL OUTSTANDING 3.250% SENIOR NOTES DUE 2051 ISSUED ON FEBRUARY 16, 2021 FOR A LIKE PRINCIPAL AMOUNT OF CORRESPONDING 3.250% SENIOR NOTES DUE 2051, WHICH HAVE BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED THE EXCHANGE OFFER EXPIRES AT 5:00 P.M., NEW YORK CITY TIME, ON , 2022 UNLESS EXTENDED (SUCH DATE AND T

Form T-1 Statement of Eligibility of Trustee under the Trust Indenture Act of 1939, as amended, of U.S. Bank Trust Company, National Association, as trustee, filed herewith.

Exhibit 25 SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 FORM T-1 STATEMENT OF ELIGIBILITY UNDER THE TRUST INDENTURE ACT OF 1939 OF A CORPORATION DESIGNATED TO ACT AS TRUSTEE ? Check if an Application to Determine Eligibility of a Trustee Pursuant to Section 305(b)(2) U.S. BANK TRUST COMPANY, NATIONAL ASSOCIATION (Exact name of Trustee as specified in its charter) 91-1821036 I.R.S. Emp

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 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in its

Biogen Inc. 2006 Non-Employee Directors Equity Plan, as amended. Filed as Exhibit 10.2 to our Quarterly Report on Form 10-Q for the quarter ended March 31, 2022.

EXHIBIT 10.2 BIOGEN INC. 2006 NON-EMPLOYEE DIRECTORS EQUITY PLAN (Approved by stockholders on May 25, 2006; as amended through March 27, 2015 and approved by stockholders on June 10, 2015; and as amended on April 6, 2022) 1. Purpose; Establishment. The Biogen Inc. 2006 Non-Employee Directors Equity Plan is intended to encourage ownership of shares of Common Stock by Non-Employee Directors of the C

BIOGEN REPORTS FIRST QUARTER 2022 RESULTS First quarter revenue $2,532 million; GAAP diluted EPS $2.06; Non-GAAP diluted EPS $3.62; EPS negatively impacted by $0.76 due to ADUHELM inventory write-offs As a result of the final national coverage determ

BIOGEN REPORTS FIRST QUARTER 2022 RESULTS First quarter revenue $2,532 million; GAAP diluted EPS $2.

egarding employment arrangement of Michel Vounatsos dated May 2, 2022

EXHIBIT 10.1 May 2, 2022 Michel Vounatsos c/o Biogen Inc. Re: Continued Employment During CEO Search Dear Michel: As we have discussed, the Board of Directors (the ?Board?) of Biogen Inc. (together with any of its subsidiaries, ?Biogen? or the ?Company?) intends to commence a search for a new Chief Executive Officer (?CEO?). This letter agreement (the ?Agreement?) reflects our mutual understanding

Departure of Directors or Certain Officers; Election of Directors; Appointment of Certain Officers; Compensatory Arrangements of Certain Officers, 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, 2022 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number) (IRS

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 State

Definitive Proxy Statement

Table of Contents 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)) ? Defi

BIIB / Biogen Inc / BlackRock Inc. Passive Investment

us09062x1037030722.txt SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No: 12) BIOGEN INC - (Name of Issuer) Common Stock - (Title of Class of Securities) 09062X103 - (CUSIP Number) December 31, 2021 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which

BIIB / Biogen Inc / PRIMECAP MANAGEMENT CO/CA/ - PRIMECAP MANAGEMENT CO/CA/ Passive Investment

UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No. 24)* Biogen Inc. (Name of Issuer) COM (Title of Class of Securities) 09062X103 (CUSIP Number) December 31, 2021 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed:

BIIB / Biogen Inc / VANGUARD GROUP INC - SCHEDULE 13G/A Passive Investment

SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 Schedule 13G Under the Securities Exchange Act of 1934 (Amendment No.: 7)* Name of issuer: Biogen Inc. Title of Class of Securities: Common Stock CUSIP Number: 09062X103 Date of Event Which Requires Filing of this Statement: December 31, 2021 Check the appropriate box to designate the rule pursuant to which this Schedule is filed: ☒ Rule 13

BIIB / Biogen Inc / BlackRock Inc. Passive Investment

us09062x1037020822.txt SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G Under the Securities Exchange Act of 1934 (Amendment No: ) BIOGEN INC - (Name of Issuer) Common Stock - (Title of Class of Securities) 09062X103 - (CUSIP Number) December 31, 2021 - (Date of Event Which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which th

BIOGEN INC.

Exhibit 21 BIOGEN INC. The following is a list of subsidiaries of Biogen Inc. as of December 31, 2021, omitting some subsidiaries which, considered in the aggregate, would not constitute a significant subsidiary. SUBSIDIARY STATE OR OTHER JURISDICTION OF INCORPORATION OR ORGANIZATION Biogen Foundation Inc. Massachusetts Biogen MA Inc. Massachusetts Biogen Realty Corporation Massachusetts Biogen Re

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 3, 2022 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

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 ? ANNUAL REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 For the fiscal year ended December 31, 2021 or ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission file number: 0-19311 BIOGEN INC. (Exact name of registrant as specified in its cha

Description of Securities.

Exhibit 4.8 DESCRIPTION OF THE REGISTRANT?S SECURITIES REGISTERED PURSUANT TO SECTION 12 OF THE SECURITIES EXCHANGE ACT OF 1934 As of December 31, 2021, Biogen Inc. (the ?Company?) has six classes of securities registered under Section 12 of the Securities Exchange Act of 1934, as amended (the ?Exchange Act?): (1) Common Stock; (2) 3.625% Senior Notes due 2022; (3) 4.050% Senior Notes due 2025; (4

BIOGEN REPORTS FOURTH QUARTER AND FULL YEAR 2021 RESULTS Revenue: Fourth quarter $2,734 million; Full Year $10,982 million GAAP diluted EPS: Fourth quarter $2.50; Full Year $10.40 Non-GAAP diluted EPS: Fourth quarter $3.39; Full Year $19.22 Engaging

BIOGEN REPORTS FOURTH QUARTER AND FULL YEAR 2021 RESULTS Revenue: Fourth quarter $2,734 million; Full Year $10,982 million GAAP diluted EPS: Fourth quarter $2.

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): January 25, 2022 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

Biogen Announces Nancy Leaming and Brian Posner to Retire from Board of Directors

Exhibit 99.1 Biogen Announces Nancy Leaming and Brian Posner to Retire from Board of Directors CAMBRIDGE, Mass., January 31, 2022? Biogen Inc. (Nasdaq: BIIB) today announced that Nancy Leaming and Brian Posner will retire from Biogen?s Board of Directors, effective at the time of the Company?s 2022 annual meeting of stockholders. Ms. Leaming, who joined the Biogen Board in 2008, was previously the

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 18, 2021 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number

Biogen Announces Alfred W. Sandrock, Jr. to Retire as Head of Research & Development

EX-99.1 2 d257656dex991.htm EX-99.1 Exhibit 99.1 Biogen Announces Alfred W. Sandrock, Jr. to Retire as Head of Research & Development CAMBRIDGE, Mass., November 15, 2021 — Biogen Inc. (Nasdaq: BIIB) announced today that Alfred “Al” W. Sandrock, Jr., M.D., Ph.D., Head of Research & Development, will retire from the Company effective December 31, 2021. A 23-year veteran of Biogen, Dr. Sandrock, 64,

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): November 15, 2021 Biogen Inc. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number

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, 2021 OR ? TRANSITION REPORT PURSUANT TO SECTION 13 OR 15(d) OF THE SECURITIES EXCHANGE ACT OF 1934 Commission File Number 0-19311 BIOGEN INC. (Exact name of registrant as specified in

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): October 20, 2021 BIOGEN INC. (Exact name of registrant as specified in its charter) Delaware 0-19311 33-0112644 (State or other jurisdiction of incorporation) (Commission File Number)

BIOGEN REPORTS THIRD QUARTER 2021 RESULTS Third quarter revenue $2,779 million; GAAP diluted EPS $2.22; Non-GAAP diluted EPS $4.77 Rolling submission initiated for lecanemab (BAN2401) in the U.S. and new data presented for aducanumab and BIIB080 (tau

BIOGEN REPORTS THIRD QUARTER 2021 RESULTS Third quarter revenue $2,779 million; GAAP diluted EPS $2.