What changed in this filing

/stocks — the workspaceLOADING

Item 1. Business

2025-02-12 compared with 2024-02-14 · 447 added, 498 removed, 758 unchanged (55% of the section changed)

Biogen is a global biopharmaceutical company focused on discovering, developing and delivering innovative therapies for people living with serious and complex diseases worldwide.

Biogen is a global biopharmaceutical company focused on discovering, developing and delivering innovative therapies for people living with serious and complex diseases.

We have a broad portfolio of medicines to treat MS, have introduced the first approved treatment for SMA, co-developed treatments to address a defining pathology of Alzheimer’s disease and launched the first approved treatment to target a genetic cause of ALS.

Through our 2023 acquisition of Reata we market the first and only drug approved in the U.S.

for the treatment of Friedreich's Ataxia in adults and adolescents aged 16 years and older.

We market the first and only drug approved in the U.S.

for the treatment of FA in adults and adolescents aged 16 years and older.

We are focused on advancing our pipeline in neurology, specialized immunology and rare diseases.

We support our drug discovery and development efforts through internal research and development programs and external collaborations.

Our marketed products include TECFIDERA, VUMERITY, AVONEX, PLEGRIDY, TYSABRI and FAMPYRA for the treatment of MS;

We support our drug discovery and development efforts through internal research and development programs, external collaborations and acquisitions.

Our marketed products include TECFIDERA, VUMERITY, AVONEX, PLEGRIDY and TYSABRI for the treatment of MS;

SPINRAZA for the treatment of SMA;

SKYCLARYS for the treatment of Friedreich's Ataxia;

SKYCLARYS for the treatment of FA;

QALSODY for the treatment of ALS;

and FUMADERM for the treatment of severe plaque psoriasis.

We also have collaborations with Eisai on the commercialization of LEQEMBI for the treatment of Alzheimer's disease and Sage on the commercialization of ZURZUVAE for the treatment of PPD and we have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's lymphoma, CLL and other conditions;

We also have collaborations with Eisai on the commercialization of LEQEMBI for the treatment of Alzheimer's disease and Sage on the commercialization of ZURZUVAE for the treatment of PPD.

We have certain business and financial rights with respect to RITUXAN for the treatment of non-Hodgkin's lymphoma, CLL and other conditions;

RITUXAN HYCELA for the treatment of non-Hodgkin's lymphoma and CLL;

4 unchanged sentences

and have the option to add other potential anti-CD20 therapies, pursuant to our collaboration arrangements with Genentech, a wholly-owned member of the Roche Group.

We commercialize a portfolio of biosimilars of advanced biologics including BENEPALI, an etanercept biosimilar referencing ENBREL, IMRALDI, an adalimumab biosimilar referencing HUMIRA, and FLIXABI, an infliximab biosimilar referencing REMICADE, in certain countries in Europe, as well as BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, in the U.S.

We commercialize a portfolio of biosimilars of advanced biologics including:

BENEPALI, an etanercept biosimilar referencing ENBREL;

IMRALDI, an adalimumab biosimilar referencing HUMIRA;

FLIXABI, an infliximab biosimilar referencing REMICADE;

and BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, in certain international markets, as well as TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, in the U.S.

and certain international markets.

We also have exclusive rights to commercialize TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA.

We continue to develop potential biosimilar product SB15, a proposed aflibercept biosimilar referencing EYLEA.

In February 2023 we announced that we are exploring strategic options for our biosimilars business.

We also have commercialization rights related to OPUVIZ, an aflibercept biosimilar referencing EYLEA.

On July 2, 2024, we completed the acquisition of HI-Bio.

As a result of this transaction we acquired HI-Bio's lead asset, felzartamab, an anti-CD38 antibody currently being evaluated for three leading indications, AMR, PMN and IgAN.

For additional information on our acquisition of HI-Bio, please read Note 2, Acquisitions , to our consolidated financial statements included in this report.

For additional information on our collaboration arrangements, please read Note 19, Collaborative and Other Relationships , to our consolidated financial statements included in this report.

Table o f Contents

KEY BUSINESS DEVELOPMENTS

The following is a summary of key developments affecting our business since the beginning of 2024.

For additional information on our collaborative and other relationships discussed below, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

ACQUISITIONS AND DIVESTITURES

HUMAN IMMUNOLOGY BIOSCIENCES

On July 2, 2024, we completed the acquisition of all of the issued and outstanding shares of HI-Bio, a privately-held clinical-stage biotechnology company focused on targeted therapies for patients with severe immune-mediated diseases.

HI-Bio's lead asset, felzartamab, an anti-CD38 antibody, is currently being evaluated for three leading indications, AMR, PMN and IgAN.

Felzartamab has received Breakthrough Therapy Designation and ODD from the FDA for development in the treatment of PMN and AMR.

Subsequent to our acquisition, felzartamab received ODD in the E.U.

in IgAN and solid organ transplantation.

The acquisition of HI-Bio is expected to augment our pipeline and build on our expertise in immunology.

Under the terms of this acquisition, we paid shareholders of HI-Bio approximately $1.15 billion at closing and may pay up to an additional $650.0 million in potential future development and regulatory milestone payments.

We funded this acquisition through available cash on hand and accounted for this acquisition as a business combination using the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations , and recorded assets acquired and liabilities assumed at their respective fair values as of the acquisition date.

For additional information on our acquisition of HI-Bio, please read Note 2, Acquisitions , to our consolidated financial statements included in this report.

SALE OF PRIORITY REVIEW VOUCHER

In April 2024 we completed the sale of our rare pediatric disease PRV, generated by the development associated with SPINRAZA, to a third party.

In consideration for the PRV we received a cash payment of $103.0 million upon the closing of the PRV purchase, of which approximately $14.4 million was paid to Ionis.

Our net portion of approximately $88.6 million was recognized in gain on sale of priority review voucher, net within our consolidated statements of income for the year ended December 31, 2024.

For additional information on the sale of our PRV, please read Note 3, Dispositions , to our consolidated financial statements included in this report.

DEVELOPMENTS IN KEY COLLABORATIVE RELATIONSHIPS

LEQEMBI (lecanemab)

United States

In July 2023 the FDA granted traditional approval of LEQEMBI, an anti-amyloid antibody for the treatment of Alzheimer's disease, which was previously granted accelerated approval by the FDA in January 2023.

Following the FDA's traditional approval of LEQEMBI, CMS confirmed broader coverage of LEQEMBI.

Additionally, in March 2023 Eisai announced that the U.S.

Veteran's Health Administration will be providing coverage of LEQEMBI to veterans living with early stages of Alzheimer's disease.

Key developments related to LEQEMBI in the U.S.

consisted of the following:

• In January 2025 the FDA approved LEQEMBI monthly IV maintenance dosing for the treatment of early Alzheimer's disease.

• In January 2025 the FDA accepted for review the BLA for LEQEMBI subcutaneous autoinjector for weekly maintenance dosing, with a PDUFA action date set for August 31, 2025.

• In July 2024 Eisai presented new clinical data from the CLARITY AD study open-label extension of LEQEMBI, demonstrating that three years of continuous LEQEMBI treatment reduced clinical decline, resulting in a clinically meaningful benefit for early Alzheimer's disease patients.

Rest of World

Key developments related to LEQEMBI (lecanemab) in rest of world markets during 2023 consisted of the following:

• In January 2024 we and Eisai announced that the SAG will convene at the request of the CHMP to discuss the MAA of lecanemab that is currently under review by the EMA.

The meeting of the SAG is expected to take place during the first quarter of 2024 and the EC decision for the MAA of lecanemab is expected during the first half of 2024.

• In January 2024 the NMPA approved LEQEMBI in China, with an expected launch date in 2024.

T able of Contents

• In December 2023 we and Eisai announced that LEQEMBI intravenous infusion was launched in Japan.

• In September 2023 the Japanese Ministry of Health, Labor and Welfare approved LEQEMBI in Japan.

• In January 2023 the EMA accepted for review the MAA for lecanemab.

• In February 2023 the BLA for lecanemab was granted Priority Review by the NMPA of China.

• In May 2023 we and Eisai announced the submission of a MAA for lecanemab to the U.K.

MHRA in Great Britain, which has been designated by the MHRA for the Innovative Licensing and Access Pathway.

Additionally, in May 2023 Health Canada accepted for review the NDS for lecanemab.

• In June 2023 we and Eisai announced the submission of a MAA for lecanemab to the Ministry of Food and Drug Safety in South Korea.

ZURZUVAE (zuranolone)

In August 2023 the FDA approved ZURZUVAE for adults with PPD, pending DEA scheduling, which was completed in October 2023.

Upon approval, ZURZUVAE for PPD became the first and only oral, once-daily, 14-day treatment that can provide rapid improvements in depressive symptoms by day 15 for women with PPD.

ZURZUVAE for PPD became commercially available in the U.S.

during the fourth quarter of 2023.

Additionally, the FDA issued a CRL for the NDA for zuranolone in the treatment of adults with MDD.

The CRL stated that the application did not provide substantial evidence of effectiveness to support the approval of zuranolone for the treatment of MDD and that an additional study or studies would be needed.

We and Sage are continuing to seek feedback from the FDA and evaluating next steps.

For additional information on our collaboration arrangement with Sage, please read Note 19, Collaborative and Other Relationships , to our consolidated financial statements included in this report.

BUSINESS COMBINATIONS

REATA ACQUISITION

On September 26, 2023, we completed the acquisition of all of the issued and outstanding shares of Reata, a biopharmaceutical company focused on developing therapeutics that regulate cellular metabolism and inflammation in serious neurologic diseases.

As a result of this transaction we acquired SKYCLARYS (omaveloxolone), the first and only drug approved in the U.S.

for the treatment of Friedreich's Ataxia in adults and adolescents aged 16 years and older, as well as other clinical and preclinical pipeline programs.

Under the terms of this acquisition, we paid Reata shareholders $172.50 in cash for each issued and outstanding Reata share, which totaled approximately $6.6 billion.

In addition, we agreed to pay approximately $983.9 million in cash for Reata's outstanding equity awards, inclusive of employer taxes, of which approximately $590.5 million was attributable to pre-acquisition services and is therefore reflected as a component of total purchase price paid.

Of the $983.9 million paid to Reata's equity award holders, we recognized approximately $393.4 million as compensation attributable to the post-acquisition service period, of which $196.4 million was recognized as a charge to selling, general and administrative expense with the remaining $197.0 million as a charge to research and development expense within our consolidated statements of income for the year ended December 31, 2023.

These amounts were associated with the accelerated vesting of stock options and RSUs previously granted to Reata employees that required no future services to vest.

For additional information on our acquisition of Reata, please read Note 2, Acquisitions , to our consolidated financial statements included in this report.

OTHER KEY DEVELOPMENTS

QALSODY (tofersen)

In April 2023 the FDA approved QALSODY for the treatment of ALS in adults who have a mutation in the SOD1 gene.

This indication is approved under accelerated approval based on reduction in plasma neurofilament light chain observed in patients treated with QALSODY.

Continued approval for this indication may be contingent upon verification of clinical benefit in confirmatory trial(s).

T able of Contents

protection for its pediatric indication, we believe that TECFIDERA is entitled to regulatory marketing protection in the E.U.

until at least February 2, 2025, and are seeking to enforce this protection.

In December 2023, the EC revoked all centralized marketing authorizations for generic versions of TECFIDERA.

As of December 31, 2023, some of the TECFIDERA generics have not yet fully exited some E.U.

markets and we expect removal of all generics from the market will take additional time.

We are closely monitoring this situation and working to enforce our legal right to market protection.

In addition, we will continue to enforce our EP 2 653 873 patent related to TECFIDERA, which expires in 2028.

CORPORATE MATTERS

FIT FOR GROWTH

In 2023 we initiated additional cost saving measures as part of our Fit for Growth program to reduce operating costs, while improving operating efficiency and effectiveness.

The Fit for Growth program is expected to generate approximately $1.0 billion in gross operating expense savings and $800.0 million in net operating expense savings by 2025, some of which will be reinvested in various initiatives.

The Fit for Growth program is currently estimated to include net headcount reductions of approximately 1,000 employees and we expect to incur restructuring charges ranging from approximately $260.0 million to $280.0 million.

For additional information on our Fit for Growth program, please read Note 4, Restructuring , to our consolidated financial statements included in this report.

Key developments related to LEQEMBI (lecanemab) in rest of world markets consisted of the following:

• In January 2025 we and Eisai announced an update regarding the ongoing regulatory review of the MAA for lecanemab in the E.U., which the CHMP of the EMA previously adopted a positive opinion on in November 2024.

The EC has asked the CHMP to consider information on the safety of lecanemab that became available after the adoption of the CHMP opinion in November 2024 and whether this may require an update of the opinion, and to consider whether the wording of the risk minimization measures in the opinion is clear enough to ensure correct implementation.

These will be discussed at the CHMP meeting in February 2025.

Table o f Contents

• In December 2024 LEQEMBI was approved by the Federal Commission for the Protection Against Sanitary Risk in Mexico.

• In November 2024 we and Eisai announced the launch of LEQEMBI in South Korea, which had been approved by the Ministry of Food and Drug Safety in South Korea in May 2024.

• In October 2024 the Therapeutic Goods Administration of Australia issued a public statement about the initial decision not to register lecanemab.

In December 2024 Eisai submitted a request for reconsideration of this decision.

• In August 2024 LEQEMBI was approved by the Medicines and Healthcare products Regulatory Agency in Great Britain and by the Ministry of Health and Prevention in the United Arab Emirates.

• In July 2024 LEQEMBI was approved in Hong Kong and Israel.

• In June 2024 we and Eisai announced the launch of LEQEMBI in China, which had been approved by the NMPA in China in January 2024.

UCB COLLABORATION

In September 2024 we and UCB announced positive topline data from the Phase 3 PHOENYCS GO study of dapirolizumab pegol, a novel Fc-free anti-CD40L drug candidate, in people living with moderate-to-severe SLE.

The Phase 3 study met the primary endpoint demonstrating clinical improvement in moderate-to-severe SLE with clinical improvements observed among key secondary endpoints.

Based on these results, UCB and Biogen initiated a second Phase 3 study in late 2024.

MANAGEMENT CHANGES

• In September 2023 we announced the appointment of Jane Grogan, Ph.D., as Executive Vice President, Head of Research.

• In April 2023 we announced the appointment of Adam Keeney, as Executive Vice President, Head of Corporate Development.

• In October 2024 we announced that Michael R.

McDonnell, Executive Vice President and Chief Financial Officer, plans to retire from Biogen on March 1, 2025.

McDonnell's retirement, Robin C.

Kramer, currently Senior Vice President and Chief Accounting Officer at Biogen, will assume the role of Executive Vice President and Chief Financial Officer.

• In January 2025 we announced the appointment of Sean Godbout as Vice President, Chief Accounting Officer and Global Corporate Controller, effective March 1, 2025, upon the transition of Robin C.

Kramer, currently Senior Vice President and Chief Accounting Officer at Biogen, to the role of Executive Vice President and Chief Financial Officer.

BOARD OF DIRECTORS UPDATE

• In November 2023 we announced Monish Patolawala will be joining our Board of Directors, effective January 1, 2024.

• In June 2023 Susan Langer joined our Board of Directors.

• In June 2023 Caroline Dorsa succeeded Stelios Papadopoulos as Chair of our Board of Directors.

• In June 2023 Stelios Papadopoulos, Alexander J.

Denner, Ph.D., William D.

Jones and Richard C.

Mulligan, Ph.D., departed from our Board of Directors.

• Effective October 1, 2024, Lloyd B.

joined our Board of Directors.

• Effective January 1, 2025, Sir Menelas (Mene) Pangalos, Ph.D.

joined our Board of Directors.

For additional information on our executive officers, please read the subsection entitled "Information about our Executive Officers" included in this report.

2 unchanged sentences

LEQEMBI (lecanemab )

• In October 2023 Eisai presented new data for LEQEMBI 100 mg/mL injection for intravenous use at the 2023 CTAD conference.

The new data suggests that there is continued benefit associated with LEQEMBI treatment as patients continued to show benefits at 24 months of treatment and after the removal of amyloid plaques.

• In September 2023 we and Eisai announced that the LEQEMBI intravenous infusion (200 mg, 500 mg, lecanemab) was approved in Japan as a treatment for slowing progression of mild cognitive impairment and mild dementia due to Alzheimer's disease.

T able of Contents

• In July 2023 we and Eisai announced the results of a detailed analysis of the Phase 3 CLARITY Alzheimer's disease study of LEQEMBI at the 2023 AAIC conference.

The study provided further Phase 3 analysis showing benefits of LEQEMBI on both amyloid-beta and tau, two underlying pathological hallmarks of Alzheimer's disease, as well as new data on subcutaneous formulation showing promising PK/PD data modeling on efficacy and safety, representing a potential new option for administering therapy.

• In March 2023 we and Eisai announced that three additional detailed analyses from the Phase 2b clinical study (Study 201) of lecanemab, evaluating the efficacy and safety of lecanemab for mild cognitive impairment due to Alzheimer's disease and mild Alzheimer's disease, were published in peer-reviewed journals.

• In October 2023 we announced new Phase 1b clinical data from the Phase 1b clinical study of BIIB080, an investigational ASO therapy targeting tau, in mild Alzheimer's disease, showing favorable trends on multiple exploratory endpoints of cognition and activities of daily living in Alzheimer's disease.

• In October 2023 JAMA Neurology published biomarker data from the placebo-controlled period and long-term extension phase of the BIIB080 Phase 1b study of the ASO which targets tau pre-mRNA in early-stage Alzheimer's disease.

This publication includes preliminary data in 46 patients which showed that the investigational therapy substantially reduced soluble and aggregated pathologic tau in patients with mild Alzheimer's disease.

• In April 2023 Nature Medicine published a manuscript detailing promising results from Biogen's multiple ascending dose Phase 1b trial, which evaluated the safety, pharmacokinetics and target engagement of Biogen's BIIB080.

• In March 2023 we presented new data from the Phase 1b clinical study of BIIB080 at the 2023 International Conference on Alzheimer's and Parkinson's Diseases, showing that BIIB080 substantially reduced tau protein levels in patients with early-stage Alzheimer's disease.

• In October 2024 Eisai presented data on benefits of long-term administration of dual-acting LEQEMBI at the 2024 CTAD conference.

The data presented additional measures resulting from the three years of continuous LEQEMBI treatment, showing that 46% of patients improved or had no decline and 33% showed improvement from baseline on the CDR-SB.

On the ADAS-Cog14 measurement scale, 46% of patients showed improvement or no decline and 43% showed improvement.

On the ADCS MCI-ADL measurement scale, 51% of patients showed improvement or no decline and 48% showed improvement.

• In July 2024 Eisai announced the results of a detailed analysis of the Phase 3 CLARITY Alzheimer's disease study of LEQEMBI at the 2024 AAIC conference.

The study provided further Phase 3 analysis showing three years of continuous LEQEMBI treatment reduced clinical decline by -0.95 on CDR-SB showing continued clinically and personally meaningful benefit for early Alzheimer's disease patients.

Table o f Contents

• Felzartamab was granted ODD in the E.U.

in IgAN and solid organ transplantation in November 2024 and December 2024, respectively.

• In October 2024 we presented complete results from the Phase 2 IGNAZ study evaluating felzartamab, an investigational anti-CD38 monoclonal antibody, in people living with IgAN during the American Society of Nephrology Kidney Week 2024.

The results from the study showed substantial reductions in proteinuria, stabilization of kidney function and sustained treatment effect more than 18 months after the last dose of felzartamab.

• In October 2024 the FDA granted felzartamab Breakthrough Therapy Designation for the treatment of late AMR without T-cell mediated rejection in kidney transplant patients.

SPINRAZA (nusinersen)

• In June 2023 we announced new data from the Phase 4 RESPOND study, which is designed to evaluate the clinical outcomes and safety following treatment with SPINRAZA in infants and toddlers with SMA who have unmet clinical needs after treatment with ZOLGENSMA (onasemnogene abeparvovec-xioi).

Interim results from the Phase 4 RESPOND study showed improved motor function in most participants treated with SPINRAZA after ZOLGENSMA.

SKYCLARYS (omaveloxolone)

• In February 2024 the EC approved SKYCLARYS in the E.U.

for the treatment of FA in adults and adolescents aged 16 years and older.

SKYCLARYS is the first treatment approved within the E.U.

for this rare, genetic, progressive neurodegenerative disease.

• In December 2023 the CHMP of the EMA issued a positive opinion recommending marketing authorization for omaveloxolone for the treatment of FA in people aged 16 years and older.

QALSODY (tofersen)

• In August 2023 the first Veteran was dosed with QALSODY following the VA's coverage for QALSODY.

• In July 2023 the European Academy of Neurology guideline recommendations on the management of ALS provided updated guidelines recommending that tofersen be offered as first-line treatment for patients with progressive ALS caused by pathogenic mutations in SOD1.

• In June 2023 the first patient with SOD1-ALS, outside of a clinical trial or early access program, was dosed with QALSODY.

• In April 2023 the FDA approved QALSODY for the treatment of ALS in adults who have a mutation in the SOD1 gene.

T able of Contents

BYOOVIZ (referencing LUCENTIS)

• In October 2023 BYOOVIZ was granted an interchangeability designation by the FDA and was deemed interchangeable to Genentech's LUCENTIS.

• In March 2023 we announced that BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, launched in Canada.

• In February 2023 Samsung Bioepis announced that BYOOVIZ launched in Germany.

TOFIDENCE (referencing ACTEMRA)

• In September 2023 the FDA approved TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, for the treatment of severe, active and progressive rheumatoid arthritis.

• In January 2025 the FDA accepted the supplemental NDA and the EMA validated the application for a higher dose regimen of nusinersen for SMA.

The higher dose regimen of nusinersen comprises a more rapid loading regimen, two 50 mg-doses 14 days apart, and higher maintenance regimen, 28 mg, every four months, compared to the currently approved dose of SPINRAZA.

• In September 2024 we announced positive topline data from the Phase 2/3 DEVOTE study of nusinersen, which evaluated the safety and efficacy of a higher dose regimen of nusinersen in treatment-naive symptomatic infants with SMA.

• In March 2024 we announced new data from the Phase 4 RESPOND study for SPINRAZA.

The study showed that neurofilament levels, an indicator of neurodegeneration, were reduced in nearly all study participants treated with SPINRAZA.

The reductions in biomarker complement previously reported RESPOND study efficacy results showing improved motor function in most participants treated with SPINRAZA after gene therapy.

• In September 2024 SKYCLARYS was approved by SWISSMEDIC for the treatment of FA in adults and adolescents aged 16 years and older.

• In July 2024 the first pediatric patient was treated in the Phase 1 study of SKYCLARYS designed to identify the appropriate dose for the pediatric population living with FA.

• In December 2024 the Japanese Ministry of Health, Labor and Welfare approved QALSODY in Japan.

• In October 2024 QALSODY was approved in China by the NMPA under the conditional approval pathway for the treatment of adults with ALS associated with a mutation in the SOD1 gene.

• In May 2024 the EC approved QALSODY in the E.U.

for the treatment of adults with ALS associated with a mutation in the SOD1 gene.

QALSODY is the first treatment approved in the E.U.

to target a genetic cause of ALS.

DISCONTINUED PROGRAMS AND STUDIES

ENVISION STUDY

In November 2023 we notified Neurimmune of our decision to terminate our collaboration and license agreement with Neurimmune, to discontinue the development and commercialization of ADUHELM and to terminate the ENVISION clinical study.

In connection with this termination, we recorded close-out costs of approximately $60.0 million in research and development expense within our consolidated statements of income for the year ended December 31, 2023.

In September 2023 we discontinued our EMBARK study for aducanumab.

In connection with this discontinuation we recorded termination costs of approximately $43.0 million in research and development expense within our consolidated statements of income for the year ended December 31, 2023 .

ACORDA COLLABORATION

In January 2024 we notified Acorda of our decision to terminate our collaboration and license agreement, effective January 1, 2025.

As a result of this termination, Acorda will regain global commercialization rights to FAMPYRA.

In June 2023 we and Denali announced plans to terminate the Phase 3 LIGHTHOUSE study for BIIB122, a small molecule inhibitor of LRRK2 in Parkinson's disease.

The protocol for the Phase 2b LUMA study for BIIB122 in patients with early-stage Parkinson’s disease was amended to now include eligible patients with a LRRK2 genetic mutation in addition to continuing to enroll eligible patients with early-stage idiopathic Parkinson’s disease.

In April 2023 we announced that we would terminate the development of BIIB093 (glibenclamide IV), currently in a Phase 3 study for LHI and a Phase 2 study for brain contusion, due to operational challenges and other strategic considerations.

In connection with this termination, we recorded close-out costs of approximately $13.2 million in research and development expense within our consolidated statements of income for the year ended December 31, 2023.

In April 2023 we announced that we will be pausing the initiation of a Phase 2b study for BIIB131 (TMS-007) for acute ischemic stroke and will continue to assess whether to initiate this study.

We sold the rights to BIIB131 to a third-party biopharmaceutical company in exchange for an upfront with potential milestones and future royalties on global sales.

In April 2023 we announced that we would discontinue further development of BIIB132 in spinocerebellar ataxia type 3, as part of our ongoing research and development prioritization initiative.

T able of Contents

SAGE COLLABORATION

In October 2024 we and Sage agreed to not pursue further development of zuranolone for the potential treatment of MDD.

This decision was based on the significant new investment and time we expect would be needed to conduct the additional studies required to support approval of this indication.

Table o f Contents

In July 2024 we and Sage announced that the Phase 2 KINETIC 2 dose-range study of BIIB124 did not meet its endpoints.

Based on these results, we discontinued our further development of BIIB124 and terminated our rights under the collaboration and license agreement specific to BIIB124, effective February 17, 2025.

SAMSUNG BIOEPIS 2019 DEVELOPMENT AND COMMERCIALIZATION AGREEMENT

In October 2024 we notified Samsung Bioepis of our decision to terminate our 2019 Development and Commercialization Agreement (the DCA Agreement) solely within the U.S.

Biogen will transfer commercialization rights for BYOOVIZ and OPUVIZ in the U.S.

and Canada back to Samsung Bioepis over a period of up to 18 months.

During this transition period, we will continue to commercialize BYOOVIZ.

The termination does not impact the other markets in the DCA Agreement.

IONIS COLLABORATION

In May 2024 we and Ionis announced that the Phase 1/2 ALSpire study of BIIB105, an investigational ASO for the potential treatment of ALS, did not meet its endpoints.

Based on these results, we discontinued our further development of BIIB105.

In May 2024 we announced that we have elected not to exercise our option to license and lead development of BIIB121, an ASO for the potential treatment of Angelman syndrome.

MERZ THERAPEUTICS (PREVIOUSLY ACORDA THERAPEUTICS, INC.)

In January 2024 we notified Acorda of our decision to terminate our collaboration and license agreement, effective January 1, 2025, whereby Acorda regained global commercialization rights to FAMPYRA.

On April 1, 2024, Acorda filed for bankruptcy protection and announced its intention to sell substantially all of Acorda's assets to a third party.

On July 10, 2024, Merz Therapeutics announced that its subsidiary Merz Pharmaceuticals LLC had completed the acquisition of FAMPYRA, and related assets from Acorda.

We are now working with Merz Therapeutics on the transition of global commercialization rights of FAMPYRA and we expect to recognize minimal revenue in 2025.

BIIB143 (cemdomespib)

In early 2025 we discontinued further development of BIIB143 (cemdomespib) for the treatment of diabetic neuropathic pain, as part of our ongoing pipeline prioritization efforts.

Table o f Contents

MARKETED PRODUCTS

The following graph shows our product revenue and revenue from anti-CD20 therapeutic programs for the years ended December 31, 2023, 2022 and 2021.

The following graph shows our product revenue, revenue from anti-CD20 therapeutic programs and Alzheimer's collaboration revenue for the years ended December 31, 2024, 2023 and 2022.

(1) MS includes TECFIDERA, VUMERITY, AVONEX, PLEGRIDY, TYSABRI and FAMPYRA.

VUMERITY became commercially available in the E.U.

during the fourth quarter of 2021.

(2) Rare disease includes SPINRAZA, QALSODY, which became commercially available in the U.S.

during the second quarter of 2023 and commercially available in the E.U.

during the second quarter of 2024, and SKYCLARYS, which was obtained as part of our acquisition of Reata in September 2023.

2 unchanged sentences

during the fourth quarter of 2023, subsequent to our acquisition.

(3) Biosimilars includes BENEPALI, IMRALDI, FLIXABI and BYOOVIZ.

BYOOVIZ became commercially available in the U.S.

during the third quarter of 2022 and commercially available in certain international markets in 2023.

(4) Anti-CD20 therapeutic programs include RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS and LUNSUMIO.

LUNSUMIO became commercially available in the U.S.

SKYCLARYS was approved and became commercially available in the E.U.

during the first quarter of 2024.

(3) Biosimilars includes BENEPALI, IMRALDI, FLIXABI, BYOOVIZ, which became commercially available in certain international markets in 2023, and TOFIDENCE, which became commercially available in the U.S.

during the second quarter of 2024.

(4) Alzheimer's collaboration revenue consists of our 50.0% share of LEQEMBI product revenue, net and cost of sales, including royalties.

(5) Anti-CD20 therapeutic programs include RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS and LUNSUMIO, which became commercially available in the U.S.

during the first quarter of 2023.

(6) Other includes FUMADERM, ADUHELM and ZURZUVAE, which became commercially available in the U.S.

during the fourth quarter of 2023.

T able of Contents

Table o f Contents

Product sales for TECFIDERA, TYSABRI and SPINRAZA each accounted for more than 10.0% of our total revenue for the years ended December 31, 2024, 2023 and 2022.

9 unchanged sentences

Product Indication Collaborator Major Markets

RRMS in the E.U.

Crohn's disease in the U.S.

RMS in the U.S.

6 unchanged sentences

RRMS in the E.U.

Crohn's disease in the U.S.

Walking ability for patients with MS Acorda France

T able of Contents

For additional information on our collaboration arrangements with Alkermes and Acorda, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

For additional information on our collaboration arrangements with Alkermes, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Table o f Contents

ALZHEIMER'S DISEASE

Alzheimer's disease, the most common form of dementia, is a progressive neurological illness that causes a gradual decline in cognitive abilities, usually during a span of seven to ten years.

Nearly all brain functions, including memory, movement, language, judgement, behavior and abstract thinking, are eventually affected.

In the U.S., Alzheimer's disease is the seventh-leading cause of death, accounting for over 120,000 deaths each year.

Alzheimer's disease is characterized by two abnormalities in the brain:

1 unchanged sentence

Amyloid plaques, which are found in the tissue between the nerve cells, are unusual clumps of a protein called beta amyloid along with degenerating bits of neurons and other cells.

Neurofibrillary tangles are bundles of twisted filaments found within neurons.

These tangles are largely made up of a protein called tau.

Our Alzheimer's disease products and major markets are as follows:

1 unchanged sentence

Alzheimer's disease Eisai U.S.

Alzheimer's disease None U.S.

In November 2023 we notified Neurimmune of our decision to terminate our collaboration and license agreement with Neurimmune and to discontinue the development and commercialization of ADUHELM.

Great Britain

United Arab Emirates

For additional information on our collaboration arrangements with Eisai, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

For additional information on the discontinuation of ADUHELM, please read Note 20, Investments in Variable Interest Entities , to our consolidated financial statements included in this report.

NEUROPSYCHIATRY

1 unchanged sentence

during the fourth quarter of 2023.

Depression is a debilitating illness that is one of the leading contributors to disability worldwide and the second leading cause of disability in the U.S.

PPD symptoms are estimated to affect approximately one in eight women who have given birth in the U.S.

2 unchanged sentences

PPD in adults Sage U.S.

For additional information on our collaboration with Sage, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Rare disease includes SPINRAZA for SMA, SKYCLARYS for FA, which was obtained as part of our acquisition of Reata in September 2023 and QALSODY for ALS, which became commercially available in the U.S.

during the second quarter of 2023.

T able of Contents

For additional information on our collaboration arrangements with Sage, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Rare disease includes SPINRAZA for SMA, QALSODY for ALS, which became commercially available in the U.S.

during the second quarter of 2023 and commercially available in the E.U.

during the second quarter of 2024, and SKYCLARYS for FA, which was obtained as part of our acquisition of Reata in September 2023.

SKYCLARYS became commercially available in the U.S.

during the second quarter of 2023 and we began recognizing revenue from SKYCLARYS in the U.S.

during the fourth quarter of 2023, subsequent to our acquisition.

SKYCLARYS was approved and became commercially available in the E.U.

during the first quarter of 2024.

SMA is characterized by loss of motor neurons in the spinal cord and lower brain stem, resulting in severe and progressive muscular atrophy and weakness.

4 unchanged sentences

People with Type 2 and Type 3 SMA produce greater amounts of SMN protein and have less severe, but still life-altering, forms of SMA.

Table o f Contents

FA is an inherited, debilitating and degenerative neuromuscular disorder that is typically diagnosed during adolescence and can ultimately lead to premature death.

Patients with FA experience progressive loss of coordination, muscle weakness and fatigue, which commonly progresses to motor incapacitation, wheelchair reliance and eventually death.

Symptoms generally first occur in children, with patients requiring a wheelchair by their teens or early-20s and generally have a life expectancy of their mid-30s.

ALS is a rare, progressive and fatal neurodegenerative disease that results in the loss of motor neurons in the brain and the spinal cord that are responsible for controlling voluntary muscle movement.

3 unchanged sentences

Genetic testing helps determine if a person's ALS is associated with a genetic mutation, even in individuals without a known family history of the disease.

SOD1-ALS is diagnosed in approximately two percent of all ALS cases.

SOD1-ALS is a mutation in the SOD1 gene, and this form of ALS is diagnosed in approximately two percent of all ALS cases.

Our Rare disease products and major markets are as follows:

1 unchanged sentence

SMA Ionis U.S.

ALS in adults with SOD1 gene Ionis U.S.

FA in adults and adolescents aged 16 years and older

FA in adults and adolescents aged 16 years and older None U.S.

ALS in adults with mutation in SOD1 gene Ionis U.S.

For additional information on our collaboration arrangements with Ionis, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

T able of Contents

Table o f Contents

Biosimilars are a group of biologic medicines that are highly similar to currently available biologic therapies developed by companies known as "originators".

Under our agreements with Samsung Bioepis, we commercialize three anti-TNF biosimilars in certain countries in Europe:

BENEPALI, an etanercept biosimilar referencing ENBREL, IMRALDI, an adalimumab biosimilar referencing HUMIRA, and FLIXABI, an infliximab biosimilar referencing REMICADE.

We have also secured the exclusive rights to commercialize BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, which is commercially available in the U.S.

and certain international markets, and TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, which was approved by the FDA during the third quarter of 2023.

We commercialize a portfolio of biosimilars of advanced biologics including:

BENEPALI, an etanercept biosimilar referencing ENBREL;

IMRALDI, an adalimumab biosimilar referencing HUMIRA;

FLIXABI, an infliximab biosimilar referencing REMICADE;

and BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, in certain international markets, as well as TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, which became commercially available in the U.S.

during the second quarter of 2024 and approved in the E.U.

during the second quarter of 2024.

We also have commercialization rights related to OPUVIZ, an aflibercept biosimilar referencing EYLEA, which was approved in the E.U.

during the fourth quarter of 2024.

Our current biosimilar products and major markets are as follows:

Product Indication Major Markets

Product Indication Collaborator Major Markets

Rheumatoid arthritis

3 unchanged sentences

Plaque psoriasis

Paediatric plaque psoriasis France

Paediatric plaque psoriasis Samsung Bioepis France

Rheumatoid arthritis

8 unchanged sentences

Ulcerative colitis

Paediatric Uveitis France

Paediatric Uveitis Samsung Bioepis France

Rheumatoid arthritis

5 unchanged sentences

Psoriatic arthritis

Psoriasis France

Psoriasis Samsung Bioepis France

Neovascular (wet) age-related macular degeneration

Macular edema following retinal vein occlusion

Myopic choroidal neovascularization U.S.

Myopic choroidal neovascularization Samsung Bioepis France

Rheumatoid arthritis

Polyarticular juvenile idiopathic arthritis

Systemic juvenile idiopathic arthritis

Giant cell arteritis

COVID-19 Bio-Thera Solutions, Ltd.

For additional information on our collaboration arrangements with Samsung Bioepis, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

T able of Contents

Table o f Contents

GENENTECH RELATIONSHIPS

We have agreements with Genentech that entitle us to certain business and financial rights with respect to RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS, LUNSUMIO, COLUMVI, which was granted accelerated approval by the FDA during the second quarter of 2023, and have the option to add other potential anti-CD20 therapies.

We have agreements with Genentech that entitle us to certain business and financial rights with respect to RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS, LUNSUMIO and COLUMVI, as well as the option to add other potential anti-CD20 therapies.

Our current anti-CD20 therapeutic programs and major markets are as follows:

16 unchanged sentences

We interact with patients, advocacy organizations and healthcare societies in order to gain insights into unmet needs.

The insights gained from these engagements help us support patients with services, programs and applications that are designed to help patients lead better lives.

The insights gained from these engagements help us support patients with services, programs and applications that are designed to help patients lead fuller, healthier lives.

Among other things, we provide customer service and other related programs for our products, such as disease and product specific websites, insurance research services, financial assistance programs and the facilitation of the procurement of our marketed products.

T able of Contents

Table o f Contents

We are dedicated to helping patients obtain access to our therapies.

Our patient representatives have access to a suite of financial assistance tools.

Our patient support representatives have access to a suite of financial assistance tools.

With those tools, we help patients understand their insurance coverage and, if needed, help patients compare insurance options and programs.

In the U.S., we have established programs that provide co-pay assistance or free product for qualified uninsured or underinsured patients, based on specific eligibility criteria.

We also provide charitable contributions to independent charitable organizations that assist patients with out-of-pocket expenses associated with their therapy.

We believe all healthcare stakeholders have a shared responsibility to ensure patients have equitable access to new, innovative medicines.

1 unchanged sentence

We have a value-based contracting program designed to align the price of our therapies to the value our therapies deliver to patients.

We also work with regulators, clinical researchers, ethicists, physicians and patient advocacy organizations and communities, among others, to determine how best to address requests for access to our investigational therapies in a manner that is consistent with our patient-focused values and compliant with regulatory standards and protocols.

In appropriate situations, patients may have access to investigational therapies through Early Access Programs, single patient access or emergency use based on humanitarian or compassionate grounds.

We also work with regulators, clinical researchers, ethicists, physicians and patient advocacy groups and communities, among others, to determine how best to address requests for access to our investigational therapies in ways that are consistent with our patient-focused values and compliant with regulatory standards and protocols.

In appropriate situations, patients may have access to investigational therapies through clinical trials, early access programs, post-trial access programs or compassionate use based on humanitarian grounds.

MARKETING AND DISTRIBUTION

2 unchanged sentences

In some countries, particularly in areas where we continue to expand into new geographic areas, we partner with third parties.

RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS and LUNSUMIO are marketed by the Roche Group and its sublicensees.

We commercialize BENEPALI, IMRALDI and FLIXABI pursuant to our agreement with Samsung Bioepis in certain countries in Europe, as well as BYOOVIZ in the U.S.

and certain international markets.

RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS, LUNSUMIO and COLUMVI are marketed by the Roche Group and its sublicensees.

We commercialize BENEPALI, IMRALDI, FLIXABI and BYOOVIZ pursuant to our agreement with Samsung Bioepis in certain international markets.

We focus our sales and marketing efforts on physicians in private practice or at major medical centers.

1 unchanged sentence

This includes our sales representatives calling on individual health care providers (in-person and virtually), advertisements, professional symposia, direct mail, digital marketing, point of care marketing, public relations and other methods.

We focus on health care provider sales and marketing efforts on specialty providers in both private practice and at major medical centers.

We focus on health care provider sales and marketing efforts on providers in both private practice and at major medical centers.

DISTRIBUTION ARRANGEMENTS

2 unchanged sentences

In other countries, the distribution of our products varies from country to country, including through wholesale distributors of pharmaceutical products and third-party distribution partners who are responsible for most marketing and distribution activities.

RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS and LUNSUMIO are distributed by the Roche Group and its sublicensees.

We distribute BENEPALI, IMRALDI and FLIXABI in certain countries in Europe and have an option to acquire exclusive rights to distribute these products in China, as well as BYOOVIZ in the U.S.

and certain international markets.

RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS, LUNSUMIO and COLUMVI are distributed by the Roche Group and its sublicensees.

We distribute BENEPALI, IMRALDI and FLIXABI in certain countries in Europe and have an option to acquire exclusive rights to distribute these products in China.

We also distribute BYOOVIZ in certain international markets and TOFIDENCE in the U.S.

Our product sales to two wholesale distributors each accounted for more than 10.0% of our total revenue for the years ended December 31, 2024, 2023 and 2022, and on a combined basis, accounted for approximately 39.3%, 36.9% and 37.9%, respectively, of our gross product revenue.

2 unchanged sentences

Patents are important for obtaining and protecting exclusive rights in our products and product candidates.

We regularly seek patent protection in the U.S.

and in selected countries outside the U.S.

for inventions originating from our research and development efforts and those we license or acquire.

We regularly seek patent protection in the U.S., the E.U.

and Japan and in selected other countries for inventions originating from our research and development efforts and those we license or acquire.

In addition, we license rights to various patents and patent applications.

T able of Contents

patents, as well as most foreign patents, are generally effective for 20 years from the date the earliest application was filed;

however, U.S.

patents on applications filed before June 8, 1995, may be effective until 17 years from the issue date, if that is later than the 20-year date.

patents on applications filed before June 8, 1995, may be effective until

Table o f Contents

17 years from the issue date, if that is later than the 20-year date.

In some cases, the patent term may be extended to recapture a portion of the term lost during regulatory review of the claimed therapeutic or, in the case of the U.S., additional patent term may be awarded due to U.S.

23 unchanged sentences

and other territories covering various aspects of our products that may, if issued, extend exclusivity beyond the expiration of the patents listed in the table.

T able of Contents

Table o f Contents

Product Territory Patent No.

1 unchanged sentence

Expiration (1)

TECFIDERA Europe 1,131,065 Formulations of dialkyl fumarates and their use for treating autoimmune diseases 2024 (2)

Europe 2,653,873 Methods of use 2028

TECFIDERA Europe 2,653,873 Methods of use 2028

PLEGRIDY U.S.

1 unchanged sentence

Europe 1,476,181 Polymer conjugates of interferon-beta-1a and uses thereof 2023 (2)

Europe 1,476,181 Polymer conjugates of interferon-beta-1a and uses thereof 2023 (4)

8,124,350 Methods of treatment 2027

8,349,321 Formulation 2024

8,815,236 Formulation 2024

8,871,449 Methods of treatment 2026

8,900,577 Formulation 2024

9,316,641 Safety-related assay 2032

9 unchanged sentences

11,292,845 Methods of treatment 2027

Europe 2,170,390 Formulation 2028

12,066,442 Methods of treatment 2032

Europe 1,872,136 Method of treatment 2026

Europe 2,170,390 Formulation 2028

Europe 2,645,106 Method of treatment 2026

Europe 3,264,094 Method of treatment 2026

Europe 3,339,865 Safety-related assay 2031

Europe 3,417,875 Formulation 2024

Europe 3,575,792 Safety-related assay 2032

FAMPYRA Europe 1,732,548 Sustained-release aminopyridine compositions for increasing walking speed in patients with MS 2025 (5)

Europe 2,377,536 Sustained-release aminopyridine compositions for treating MS 2025 (6)

Europe 4,152,004 Safety-related assay 2031

VUMERITY U.S.

4 unchanged sentences

Prodrugs of fumarates and their use in treating various diseases 2034

Europe 3,253,377 Formulation 2035

SPINRAZA U.S.

7 unchanged sentences

10,436,802 Methods for Treating Spinal Muscular Atrophy 2035

12,013,403 Methods for Treating Spinal Muscular Atrophy 2036

Europe 1,910,395 Compositions and methods for modulation of SMN2 splicing 2026 (3)

3 unchanged sentences

Europe 3,449,926 Compositions and methods for modulation of SMN2 splicing 2030 (6)

T able of Contents

8,025,878 Protofibril selective antibodies and the use thereof 2027 (1)(5)

Table o f Contents

Product Territory Patent No.

1 unchanged sentence

Expiration (1)

8,906,367 Method of providing disease-specific binding molecules and targets 2032 (11)

10,131,708 Methods of treating Alzheimer's disease 2028

8,025,878 Protofibril selective antibodies and the use thereof 2027 (1)(11)

10,385,341 Compositions for modulating SOD-1 expression 2035 (1)(5)

1 unchanged sentence

10,968,453 Compositions for modulating SOD-1 expression 2035

Europe 3,126,499 Compositions for modulating SOD-1 expression 2035 (1)(8)

Europe 3,757,214 Compositions for modulating SOD-1 expression 2035

ZURZUVAE U.S.

14 unchanged sentences

Oleanolic Acid Derivatives with Amino and other Modifications at C-17 (Treatment Method) 2029 (5)

Europe 2,276,493 Antioxidant Inflammation Modulators:

Oleanolic Acid Derivatives with Amino and other Modifications at C-17 (Composition) 2029

Europe 2,841,445 2,2-Difluoropropionamide Derivatives of Bardoxolone Methyl, Polymorphic Forms and Methods of Use Thereof (Composition) 2033 (7)

Europe 3,444,261 2,2-Difluoropropionamide Derivatives of Bardoxolone Methyl, Polymorphic Forms and Methods of Use Thereof (Composition) 2033

Footnotes follow on next page.

T able of Contents

Table o f Contents

(1) I n addition to patent protection, certain of our products are entitled to regulatory exclusivity in the U.S.

1 unchanged sentence

Product Territory Expected Expiration

TECFIDERA E.U.

PLEGRIDY U.S.

5 unchanged sentences

(4) This patent is subject to granted SPCs in certain European countries, which extended the patent term in those countries to 2031.

(5) This patent is subject to granted SPCs in certain European countries, which extended the patent term in those countries to 2026.

(6) This patent is subject to granted SPCs in certain European countries, which extended the patent term in those countries to 2026.

(5) A patent with this subject matter may be entitled to patent term extension in the U.S.

(6) This patent is subject to granted SPCs in certain European countries, which extended the patent term in those countries to 2032.

(7) This patent is subject to granted SPCs in certain European countries, which extended the patent term in those countries to 2038.

(9) A patent with this subject matter may be entitled to patent term extension in the U.S.

(8) This patent is subject to granted SPCs in certain European countries, which extended the patent term in those countries to 2039.

5 unchanged sentences

Risk Factors included in this report, and the discussion of legal proceedings related to certain patents described above is set forth in Note 21, Litigation, to our consolidated financial statements included in this report.

T able of Contents

Table o f Contents

Competition in the biopharmaceutical industry and the markets in which we operate is intense.

8 unchanged sentences

The introduction of new products or technologies, including the development of new processes or technologies by competitors or new information about existing products or technologies, results in increased competition for our marketed products and pricing pressure on our marketed products.

The development of new or improved treatment options or standards of care or cures for the diseases our products treat reduces and could eliminate the use of our products or may limit the utility and application of ongoing clinical trials for our product candidates.

In addition, the commercialization of certain of our own approved products, products of our collaborators and pipeline product candidates may negatively impact future sales of our existing products.

The development of new or improved treatment options could eliminate the use of our products or may limit the utility and application of ongoing clinical trials for our product candidates.

Similarly, developments of new standards of care practices, treatment options or cures for the diseases our products treat could have similar impacts.

We believe our long-term competitive position depends upon our success in discovering and developing innovative, cost-effective products that serve unmet medical needs, along with our ability to manufacture products efficiently and to launch and market them effectively in a highly competitive environment.

1 unchanged sentence

Risk Factors included in this report.

MULTIPLE SCLEROSIS

Our MS products and revenue streams continue to face increasing competition in many markets from the introduction of generic versions, prodrugs and biosimilars of existing products and products approved under abbreviated regulatory pathways.

GENERIC AND BIOSIMILARS COMPETITION

Certain of our products already face, or may face in the future, competition from the introduction of generic versions, prodrugs and biosimilars of existing products and products approved under abbreviated regulatory pathways.

Such products are likely to be sold at substantially lower prices than branded products.

2 unchanged sentences

In addition, in some markets, when a generic or biosimilar version of one of our products is commercialized, it may be automatically substituted for our product and significantly reduce our revenue in a short period of time.

Multiple TECFIDERA generic entrants are now in North America, Brazil and certain European countries and have deeply discounted prices compared to TECFIDERA.

We are defending the validity of our EP 2 653 873 patent related to TECFIDERA and expiring in 2028 in opposition proceedings in the European Patent Office.

We are also engaged in litigation in Europe to defend and enforce national counterparts of our EP 2 653 873 patent, with mixed results.

The generic competition for TECFIDERA has significantly reduced our TECFIDERA revenue and we expect that TECFIDERA revenue will continue to decline.

B i osimilar products referencing RITUXAN have launched in the U.S and are being offered at lower prices.

This competition has had a significant adverse impact on the pre-tax profits of our collaboration arrangements with Genentech, as the sales of RITUXAN have decreased substantially compared to prior periods.

We expect that biosimilar competition will continue to increase as these products capture additional market share and that this will have a significant adverse impact on our co-promotion profits in the U.S.

in future years.

Table o f Contents

A biosimilar entrant of TYSABRI was approved in the U.S.

We expect that future sales of TYSABRI may be adversely affected by the entrance of this biosimilar.

MULTIPLE SCLEROSIS

Competition in the MS market is intense.

Along with us, a number of companies are working to develop additional treatments for MS that may in the future compete with our MS products.

One such product that was approved in the U.S.

One competing product that was approved in the U.S.

in 2017 and in the E.U.

in 2018 is OCREVUS, a treatment for RMS and PPMS that was developed by Genentech.

While we have a financial interest in OCREVUS, future sales of our MS products may be adversely affected if OCREVUS continues to gain market share, or if other MS products that we or our competitors are developing are commercialized.

T able of Contents

TECFIDERA, AVONEX, PLEGRIDY, TYSABRI and VUMERITY each compete with one or more of the following branded products as well as generic and biosimilar versions of some of these products:

Competing Product Competitor

AUBAGIO (teriflunomide) Sanofi Genzyme

BAFIERTAM (monomethyl fumarate) Banner Life Sciences

BETASERON/BETAFERON (interferon-beta-1b) Bayer Group

BRIUMVI (ublituximab-xiiy) TG Therapeutics, Inc.

COPAXONE (glatiramer acetate) Teva Pharmaceuticals Industries Ltd.

EXTAVIA (interferon-beta-1b) Novartis AG

GILENYA (fingolimod) Novartis AG

GLATOPA (glatiramer acetate) Sandoz, a division of Novartis AG

KESIMPTA (ofatumumab) Novartis AG

LEMTRADA (alemtuzumab) Sanofi Genzyme

MAVENCLAD (cladribine) EMD Serono

MAYZENT (siponimod) Novartis AG

OCREVUS (ocrelizumab) Genentech

PONVORY (ponesimod) Janssen Pharmaceutical Companies of Johnson & Johnson

REBIF (interferon-beta-1) EMD Serono

TYRUKO (natalizumab-sztn) Sandoz, a division of Novartis AG

ZEPOSIA (ozanimod) Bristol Myers Squibb Company

Multiple TECFIDERA generic entrants are now in North America, Brazil and certain E.U.

countries and have deeply discounted prices compared to TECFIDERA.

Following a favorable March 2023 decision of the CJEU affirming TECFIDERA's right to regulatory data and marketing protection and the EC determination in May 2023 that TECFIDERA is entitled to an additional year of market protection for its pediatric indication, we believe that TECFIDERA is entitled to regulatory marketing protection in the E.U.

until at least February 2, 2025, and are seeking to enforce this protection.

In December 2023, the EC revoked all centralized marketing authorizations for generic versions of TECFIDERA.

As of December 31, 2023, some of the TECFIDERA generics have not yet fully exited some E.U.

markets and we expect removal of all generics from the market will take additional time.

We are closely monitoring this situation and working to enforce our legal right to market protection.

In addition, we will continue to enforce our EP 2 653 873 patent related to TECFIDERA, which expires in 2028.

The generic competition for TECFIDERA has significantly reduced our TECFIDERA revenue and we expect that TECFIDERA revenue will continue to decline in the future.

We are also aware of a biosimilar entrant of TYSABRI that was approved in the U.S.

in August 2023 and the E.U.

in September 2023.

We believe that future sales of TYSABRI may be adversely affected by the entrance of this biosimilar.

For additional information on the U.S.

patent litigation related to a TYSABRI biosimilar, please read Note 21, Litigation , to our consolidated financial statements included in this report.

Another competing product that was approved in the U.S.

in 2020 and the E.U.

in 2021 is KESIMPTA, a treatment for RMS that was developed by Novartis AG.

While we have a financial interest in OCREVUS, future sales of our MS products may be adversely affected if OCREVUS and KESIMPTA continue to gain market share, or if other MS products that we or our competitors are developing are commercialized.

ALZHEIMER'S DISEASE

2 unchanged sentences

Along with us, several companies are working to develop additional treatments.

Most recently, we codeveloped LEQEMBI, a treatment to address a defining pathology of Alzheimer's disease and we and our collaborator Eisai are in the process of launching this product.

We and our collaboration partner Eisai co-commercialize LEQEMBI, an anti-amyloid antibody for the treatment of Alzheimer's disease.

In 2024 a competing product, KISUNLA, a treatment for early symptomatic Alzheimer's disease that was developed by Eli Lilly and Company, was approved in the U.S.

We are aware of other products now in development that, if approved, may also compete with LEQEMBI.

T able of Contents

SPINAL MUSCULAR ATROPHY

We face competition from a gene therapy product ZOLGENSMA (onasemnogene abeparvovec-xioi) and an oral product EVRYSDI (risdiplam).

We expect that we will experience competition from both products in additional jurisdictions in the future, which may adversely affect our sales of SPINRAZA.

Additionally, we are aware of other products now in development that, if launched, may also compete with SPINRAZA.

Future sales of SPINRAZA may be adversely affected by the commercialization of competing products.

FRIEDREICH'S ATAXIA

SKYCLARYS is the first treatment on the market for this indication and could face future competition from pipeline programs under development.

BENEPALI, IMRALDI and FLIXABI, the three biosimilar products we currently commercialize in certain countries in Europe pursuant to an agreement with Samsung Bioepis, compete with their reference products, ENBREL, HUMIRA and REMICADE, respectively, as well as other biosimilars of those reference products.

BYOOVIZ, a biosimilar product we currently commercialize in the U.S.

and certain international markets pursuant to an agreement with Samsung Bioepis, competes with its reference product LUCENTIS, as well as other biosimilars of this reference product.

GENENTECH RELATIONSHIPS IN OTHER INDICATIONS

RITUXAN, RITUXAN HYCELA, GAZYVA and LUNSUMIO in Oncology

RITUXAN, RITUXAN HYCELA, GAZYVA and LUNSUMIO compete with a number of therapies in the oncology market, including TREANDA (bendamustine HCL), ARZERRA (ofatumumab), IMBRUVICA (ibrutinib) and ZYDELIG (idelalisib) and other new innovative oncological therapies.

B i osimilar products referencing RITUXAN have launched in the U.S and are being offered at lower prices.

in future years.

RITUXAN in Rheumatoid Arthritis

RITUXAN competes with several different types of therapies in the rheumatoid arthritis market, including, among others, traditional disease-modifying anti-rheumatic drugs such as steroids, methotrexate and cyclosporine, TNF inhibitors, ORENCIA (abatacept), ACTEMRA (tocilizumab) and XELJANZ (tofacitinib) and biosimilar versions of RITUXAN.

We are also aware of other products, including biosimilars, in development that, if approved, may compete with RITUXAN in the rheumatoid arthritis market.

We expect that we will experience competition from both products in additional jurisdictions in the future, as well as from the launch of new formulations of those products, which may adversely affect our sales of SPINRAZA.

Table o f Contents

RESEARCH AND DEVELOPMENT PROGRAMS

A commitment to research is fundamental to our mission.

A commitment to research and development is fundamental to our mission.

Our research efforts are focused on better understanding the underlying biology of diseases so we can discover and deliver treatments that have the potential to make a real difference in the lives of patients with high unmet medical needs.

2 unchanged sentences

As part of our ongoing research and development efforts, we have devoted significant resources to conducting clinical studies to advance the development of new pharmaceutical products and technologies and to explore the utility of our existing products in treating disorders beyond those currently approved in their labels.

T able of Contents

For additional information on our research and development expense included in our consolidated statements of income, please read Item 7.

5 unchanged sentences

Alzheimer's Disease and

Dementia Lecanemab (Aβ mAb) (1)(2) - Alzheimer's

Filed in the E.U.

and Other Markets

Dementia Lecanemab (Aβ mAb) (1)(2) - Early Alzheimer's

Lecanemab (Aβ mAb) (1) - Preclinical Alzheimer's

Lecanemab (Aβ mAb) (1) - Subcutaneous autoinjector maintenance - Early Alzheimer's

Regulatory Review

Lecanemab (Aβ mAb) (1) - Subcutaneous autoinjector initiation - Early Alzheimer's

BIIB080 (tau ASO) (1) - Alzheimer's

BIIB113 (OGA inhibitor) - Alzheimer's Phase 1

Neuropsychiatry Zuranolone (GABA A PAM) (1)(4) - MDD

Zuranolone (GABA A PAM) (1) - PPD

Approved in the U.S.

Specialized Immunology Dapirolizumab pegol (anti-CD40L) (1) - SLE

Neuropsychiatry Zuranolone (GABA A PAM) (1)(3) - PPD

Approved/Regulatory Review

Specialized Immunology Felzartamab (anti-CD38 mAb) - AMR Phase 2

Felzartamab (anti-CD38 mAb) - IgAN Phase 2

Felzartamab (anti-CD38 mAb) - PMN Phase 2

Felzartamab (anti-CD38 mAb) - lupus nephritis Phase 1

Izastobart (C5aR1 mAb) - complement mediated disease Phase 1

Dapirolizumab pegol (anti-CD40L) (1) - SLE

Litifilimab (anti-BDCA2) - SLE Phase 3

Litifilimab (anti-BDCA2) - CLE Phase 3

Neuromuscular Disorders Omaveloxolone (Nrf2 activator) - FA Approved in the U.S.

Neuromuscular Disorders Omaveloxolone (Nrf2 activator) - FA (4)

Omaveloxolone (Nrf2 activator) - Pediatric FA Phase 1

Tofersen (SOD1 ASO) (1)(5) - SOD1 ALS

Approved in the U.S.;

Filed in the E.U.

BIIB105 (ataxin-2 ASO) # - ALS

HD Nusinersen (SMN2 splice modulator) - SMA Regulatory Review

BIIB115 (SMN ASO) (1) - SMA

Parkinson's and

Movement Disorders BIIB122 (LRRK2 inhibitor) (1) - Parkinson's

BIIB124 (GABA A PAM) (1) - Essential Tremor

BIIB094 (LRRK2 ASO) # - Parkinson's

BIIB101 (a-syn ASO) # - Multiple System Atrophy

Parkinson's and Movement Disorders BIIB122 (LRRK2 inhibitor) (1) - Parkinson's

Multiple Sclerosis BIIB091 (peripheral BTK inhibitor) - MS Phase 2

BIIB107 (anti-VLA4) - MS Phase 1

Genetic Neurodevelopmental Disorders BIIB121 (UBE3A ASO) # - Angelman Syndrome

Neuropathic Pain Cemdomespib (Hsp90 modulator) - DPNP Phase 2

(1) Collaboration program

1 unchanged sentence

in January 2023 and traditional approval in the U.S.

in July 2023, Japan in September 2023 and China in January 2024 under the brand name LEQEMBI.

in July 2023.

Outside the U.S., LEQEMBI is now approved in Japan (September 2023), China (January 2024), South Korea (May 2024), Hong Kong (July 2024), Israel (July 2024), United Arab Emirates (August 2024), Great Britain (August 2024) and Mexico (December 2024).

(3) Granted approval in the U.S.

in August 2023, pending DEA scheduling, which was completed in October 2023, under the brand name ZURZUVAE.

(4) Granted approval in the U.S.

in February 2023 and the E.U.

in February 2024, under the brand name SKYCLARYS.

(5) Granted accelerated approval in the U.S.

in April 2023 under the brand name QALSODY.

(4) In August 2023 the FDA issued a CRL for the NDA for zuranolone in the treatment of adults with MDD.

We and Sage are continuing to seek feedback from the FDA and evaluating next steps.

in April 2023, the E.U.

in May 2024 and China in October 2024 under the brand name QALSODY.

# Option agreement

Table o f Contents

For information about certain of our agreements with collaborators and other third parties, please read the subsection entitled Business Relationships below and Note 2, Acquisitions , Note 19, Collaborative and Other Relationships, and Note 20, Investments in Variable Interest Entities, to our consolidated financial statements included in this report.

T able of Contents

BUSINESS RELATIONSHIPS

9 unchanged sentences

SAGE THERAPEUTICS, INC .

We have a global collaboration and license agreement with Sage to jointly develop and commercialize ZURZUVAE (zuranolone) for the treatment of PPD and potential treatment of MDD and BIIB124 (SAGE-324) for the potential treatment of essential tremor with potential in other neurological conditions such as epilepsy.

We have a global collaboration and license agreement with Sage to jointly develop and commercialize ZURZUVAE (zuranolone) for the treatment of PPD.

Under this collaboration, both companies will share equal responsibility and costs for development as well as profits and losses for commercialization in the U.S.

Outside of the U.S., we are responsible for development and commercialization, excluding Japan, Taiwan and South Korea, with respect to zuranolone and may pay Sage potential tiered royalties in the high teens to low twenties.

We have an exclusive, worldwide option and collaboration agreement with Ionis relating to the development and commercialization of antisense therapeutics for up to three gene targets.

Under a separate collaboration and license agreement with Ionis, we have an exclusive, worldwide license to develop and commercialize SPINRAZA for the treatment of SMA.

We also have a 10-year exclusive collaboration agreement with Ionis to develop novel ASO drug candidates for a broad range of neurological diseases.

In addition, we have research collaboration agreements with Ionis under which both companies perform discovery level research and will develop and commercialize new ASO drug candidates for the potential treatment of SMA and additional antisense or other therapeutics for the potential treatment of neurological diseases.

In December 2018 we exercised our option with Ionis and obtained a worldwide, exclusive, royalty-bearing license to develop and commercialize QALSODY (tofersen), for the treatment of ALS with SOD1 mutations.

T able of Contents

Outside of the U.S., we are responsible for development and commercialization, excluding Japan, Taiwan and South Korea.

We have several exclusive, worldwide option and collaboration agreements with Ionis to develop and commercialize antisense therapeutics, including SPINRAZA for the treatment of SMA and QALSODY for the treatment of ALS with SOD1 mutations, as well as other research programs for a broad range of neurological diseases.

Under these agreements, we have the option to license therapies arising out of these collaborations and will be responsible for their development and commercialization.

Ionis may receive potential milestones and royalties on net sales if we successfully develop the product candidate after option exercise.

We have a collaboration agreement with UCB to jointly develop and commercialize dapirolizumab pegol, an anti-CD40L pegylated Fab, for the potential treatment of SLE and other future agreed indications.

Both companies will share equally costs incurred for agreed indications, including research, development, sales and marketing expense.

If marketing approval is obtained, both companies will jointly commercialize dapirolizumab pegol and share profits and losses equally.

Table o f Contents

We have a collaboration and license agreement with Denali to co-develop and co-commercialize Denali's small molecule inhibitors of LRRK2 for Parkinson's disease.

3 unchanged sentences

SAMSUNG BIOEPIS

We have an agreement with Samsung Bioepis to commercialize, over a 10-year term, three anti-TNF biosimilar product candidates in certain countries in Europe and, in the case of BENEPALI, Japan.

Under this agreement, we are commercializing BENEPALI, an etanercept biosimilar referencing ENBREL, IMRALDI, an adalimumab biosimilar referencing HUMIRA, and FLIXABI, an infliximab biosimilar referencing REMICADE, in certain countries in Europe.

In December 2019 we completed a transaction with Samsung Bioepis and acquired an option to extend our existing commercial agreement with Samsung Bioepis for BENEPALI, IMRALDI and FLIXABI in certain countries in Europe.

We have also secured the exclusive rights to commercialize BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, which has been approved in the U.S.

and certain international markets, and TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, which was approved in the U.S.

during the third quarter of 2023.

We have an agreement with Samsung Bioepis to commercialize three anti-TNF biosimilar product candidates in certain countries in Europe.

We have also secured the exclusive rights to commercialize BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, in certain international markets, and OPUVIZ, an aflibercept biosimilar referencing EYLEA, which was approved in the E.U.

during the fourth quarter of 2024.

In addition to our commercialization agreements with Samsung Bioepis, we license certain of our proprietary technology to Samsung Bioepis in connection with Samsung Bioepis' development, manufacture and commercialization of its biosimilar products.

Both companies will share equally costs incurred for agreed indications, including research, development, sales and marketing expense.

If marketing approval is obtained, both companies will co-promote dapirolizumab pegol and share profits and losses equally.

Our current and contemplated activities and the products, technologies and processes that result from such activities are subject to substantial government regulation.

11 unchanged sentences

The FDA has substantial discretion in the product approval process, and it is impossible to predict with any certainty whether and when the FDA will grant marketing approval.

The agency may require the sponsor of a BLA or NDA to conduct additional clinical studies or to provide other scientific or technical information about the product, and these additional requirements may lead to

T able of Contents

unanticipated delays or expenses.

Furthermore, even if a product is approved, the approval may be subject to limitations based on the FDA's interpretation of the existing pre-clinical and/or clinical data.

5 unchanged sentences

When approval is based on surrogate endpoints or clinical endpoints other than survival or morbidity, the sponsor will be required to provide the FDA with confirmatory data post-approval to verify and describe clinical benefit.

Under the FDA's accelerated approval regulations, if the FDA concludes that a drug that has been shown to be effective can be safely used only if distribution or use is restricted, it may require certain post-marketing restrictions to assure safe use.

Under the FDA's accelerated approval regulations, if the FDA

Table o f Contents

concludes that a drug that has been shown to be effective can be safely used only if distribution or use is restricted, it may require certain post-marketing restrictions to assure safe use.

In addition, for products approved under accelerated approval, sponsors may be required to submit all copies of their promotional materials, including advertisements, to the FDA at least 30 days prior to initial dissemination.

8 unchanged sentences

“Priority review” only applies to applications (original or efficacy supplement) for a drug that treats a serious condition and, if approved, would provide a significant improvement in safety or effectiveness of the treatment, diagnosis or prevention of a serious condition.

Priority review may also be granted for any supplement that proposes a labeling change due to studies completed in response to a written request from the FDA for pediatric studies, for an application for a drug that has been designated as a qualified infectious disease product or for any application or supplement for a drug submitted with a priority review voucher.

In December 2016 the FDA issued a rare pediatric disease priority review voucher to us in connection with the approval of SPINRAZA.

Additionally, as part of our acquisition of Reata in September 2023 we obtained a rare pediatric disease priority review voucher in connection with the approval of SKYCLARYS, which was approved by the FDA in February 2023.

As part of our acquisition of Reata in September 2023 we obtained a rare pediatric disease PRV in connection with the approval of SKYCLARYS, which was approved by the FDA in February 2023.

POST-MARKETING STUDIES

10 unchanged sentences

Side effects or adverse events that are reported during clinical trials can delay, impede or prevent marketing approval.

Based on new safety information that emerges after approval, the FDA can mandate product labeling changes, impose a new REMS or the addition of elements to

T able of Contents

an existing REMS, require new post-marketing studies (including additional clinical trials) or suspend or withdraw approval of the product.

Based on new safety information that emerges after approval, the FDA can mandate product labeling changes, impose a new REMS or the addition of elements to an existing REMS, require new post-marketing studies (including additional clinical trials) or suspend or withdraw approval of the product.

These requirements may affect our ability to maintain marketing approval of our products or require us to make significant expenditures to obtain or maintain such approvals.

3 unchanged sentences

FDA regulatory review may result in denial or modification of the planned changes, or requirements to conduct additional tests or evaluations that can substantially delay or increase the cost of the planned changes.

Table o f Contents

REGULATION OF PRODUCT ADVERTISING AND PROMOTION

20 unchanged sentences

Under the centralized procedure, a company submits a single application to the EMA.

The marketing authorization application is similar to the NDA or BLA in the U.S.

The MAA is similar to the NDA or BLA in the U.S.

and is evaluated by the CHMP, the expert scientific committee of the EMA responsible for human medicines.

7 unchanged sentences

member state only;

T able of Contents

• a decentralized procedure, where applicants submit identical applications to several E.U.

9 unchanged sentences

may be truncated under accelerated assessment for products that address an unmet medical need.

In addition, conditional marketing authorizations may be granted for products in the interest of public health, where the benefit of immediate availability outweighs the risk of having less comprehensive data than normally required.

In addition, conditional marketing authorizations may be granted for products in the interest of public health, where the benefit of immediate availability

Table o f Contents

outweighs the risk of having less comprehensive data than normally required.

Conditional marketing authorizations are valid for one year and can be renewed annually.

24 unchanged sentences

Failure of such third parties to comply with current GCP can likewise result in rejection of our clinical trial data or other sanctions.

T able of Contents

In April 2014 the EC adopted a new Clinical Trial Regulation, which was entered into force in June 2014 but did not apply until January 2022.

7 unchanged sentences

the PPACA amended the PHS Act to authorize the FDA to approve biological products, referred to as biosimilars or follow-on biologics, that are shown to be "highly similar" to previously approved biological products based upon potentially abbreviated data packages.

The biosimilar must show it has no clinically meaningful differences in terms of safety and effectiveness from the reference product, and only minor differences in clinically inactive components are allowable in biosimilar products.

The biosimilar must show it has no clinically meaningful

Table o f Contents

differences in terms of safety and effectiveness from the reference product, and only minor differences in clinically inactive components are allowable in biosimilar products.

The approval pathway for biosimilars does, however, grant a biologics manufacturer a 12-year period of exclusivity from the date of approval of its biological product before biosimilar competition can be introduced.

8 unchanged sentences

Under the U.S.

Orphan Drug Act, the FDA may grant orphan drug designation to drugs or biologics intended to treat a “rare disease or condition,” which generally is a disease or condition that affects fewer than 200,000 individuals in the U.S.

If a product which has an orphan drug designation subsequently receives an initial FDA approval for the indication for which it has such designation, the product is entitled to orphan exclusivity, i.e., the FDA may not approve any other applications to market the same drug for the same indication for a period of seven years following marketing approval, except in certain very limited circumstances, such as if the later product is shown to be clinically superior to the orphan product.

Orphan Drug Act, the FDA may grant ODD to drugs or biologics intended to treat a “rare disease or condition,” which generally is a disease or condition that affects fewer than 200,000 individuals in the U.S.

If a product which has an ODD subsequently receives an initial FDA approval for the indication for which it has such designation, the product is entitled to orphan exclusivity, i.e., the FDA may not approve any other applications to market the same drug for the same indication for a period of seven years following marketing approval, except in certain very limited circumstances, such as if the later product is shown to be clinically superior to the orphan product.

Legislation similar to the U.S.

1 unchanged sentence

In the E.U., medicinal products that receive and maintain an orphan designation are entitled to 10 years of market exclusivity following approval, protocol assistance and access to the centralized procedure for marketing authorization.

SPINRAZA has been granted orphan drug designation in the U.S., the E.U.

QALSODY and SKYCLARYS have been granted orphan drug designation in the U.S.

SPINRAZA has been granted ODD in the U.S., the E.U.

QALSODY and SKYCLARYS have been granted ODD in the U.S.

and the E.U.;

and felzartamab has been granted ODD in the U.S.

for development in the treatment of PMN and AMR and in the E.U.

in IgAN and solid organ transplantation.

REGULATION PERTAINING TO PRICING AND REIMBURSEMENT

6 unchanged sentences

Other payors, including managed care organizations, health insurers, pharmacy benefit managers, government health administration authorities and private health insurers, seek price discounts or rebates in connection with the placement of our products on their formularies and, in some cases, may impose restrictions on access, coverage or pricing of particular drugs based on perceived value.

T able of Contents

WITHIN THE U.S.

6 unchanged sentences

In addition, if we fail to provide information timely or we are found to have knowingly submitted false information to the government, the statute governing the Medicaid Drug Rebate Program provides for civil monetary penalties.

Table o f Contents

Medicare is a federal program that is administered by the federal government.

10 unchanged sentences

In addition, manufacturers, including us, are required to provide to the CMS a discount of up to 70.0% on brand name prescription drugs utilized by Medicare Part D beneficiaries when those beneficiaries reach the coverage gap in their drug benefits.

On August 16, 2022, President Biden signed into law the IRA, which provides for (i) the government to negotiate prices for select high-cost Medicare Part D drugs (beginning in 2026) and Part B drugs (beginning in 2028), (ii) manufacturers to pay a rebate for Medicare Part B and Part D drugs when prices increase faster than inflation beginning in 2022 for Part D and 2023 for Part B, and (iii) Medicare Part D redesign which replaces the current coverage gap provisions and establishes a $2,000 cap for out-of-pocket costs for Medicare beneficiaries beginning in 2025, with manufacturers being responsible for 10.0% of costs up to the $2,000 cap and 20.0% after that cap is reached.

On August 16, 2022, the IRA was signed into law, which provides for (i) the government to negotiate prices for select high-cost Medicare Part D drugs (beginning in 2026) and Part B drugs (beginning in 2028), (ii) manufacturers to pay a rebate for Medicare Part B and Part D drugs when prices increase faster than inflation beginning in 2022 for Part D and 2023 for Part B, and (iii) Medicare Part D redesign which replaces the current coverage gap provisions and establishes a $2,000 cap for out-of-pocket costs for Medicare beneficiaries beginning in 2025, with manufacturers being responsible for up to 10.0% of costs up to the $2,000 cap and up to 20.0% after that cap is reached.

The result of these forthcoming changes for manufacturers, including us, may include:

1 unchanged sentence

ii) new rebate liability for drugs subject to the inflation provisions, and iii) potential significant additional costs related to the Part D re-design.

However, as the degree of impact from this legislation on our business depends on a number of forthcoming implementation actions by regulatory authorities, the full extent of the IRA’s impact on our sales and, in turn, our business, remains unclear.

• Federal Agency Discounted Pricing :

8 unchanged sentences

To maintain coverage of our products under the Medicaid Drug Rebate Program and Medicare Part B, we are required to extend significant discounts to certain covered entities that purchase products under Section 340B of the PHS pharmaceutical pricing program.

Purchasers eligible for discounts include hospitals that serve a disproportionate share of financially needy patients, community health clinics and

T able of Contents

other entities that receive certain types of grants under the PHS Act.

Purchasers eligible for discounts include hospitals that serve a disproportionate share of financially needy patients, community health clinics and other entities that receive certain types of grants under the PHS Act.

For all of our products, we must agree to charge a price that will not exceed the amount determined under statute (the “ceiling price”) when we sell outpatient drugs to these covered entities.

6 unchanged sentences

Governments may use a variety of cost-containment measures to control the cost of products, including price cuts, mandatory rebates, value-based pricing and reference pricing (i.e., referencing prices in other countries and using those reference prices to set a price).

Budgetary pressures in many countries are continuing to cause governments to consider or implement various cost-containment measures, such as price freezes, increased price cuts and rebates and expanded generic substitution and patient cost-sharing.

Budgetary pressures in many countries are continuing to cause governments

Table o f Contents

to consider or implement various cost-containment measures, such as price freezes, increased price cuts and rebates and expanded generic substitution and patient cost-sharing.

REGULATION PERTAINING TO SALES AND MARKETING

16 unchanged sentences

Outside the U.S., other countries have implemented requirements for disclosure of financial interactions with healthcare providers and additional countries may consider or implement such laws.

OTHER REGULATIONS

OTHER LAWS AND REGULATIONS

FOREIGN ANTI-CORRUPTION

4 unchanged sentences

In many countries, the health care professionals we regularly interact with may meet the FCPA's definition of a foreign government official.

The FCPA also requires public companies to make and keep books and records that

T able of Contents

accurately and fairly reflect their transactions and to devise and maintain an adequate system of internal accounting controls.

The FCPA also requires public companies to make and keep books and records that accurately and fairly reflect their transactions and to devise and maintain an adequate system of internal accounting controls.

The laws to which we are subject also include the U.K.

8 unchanged sentences

By local ordinance, we are required to, among other things, comply with the NIH Guidelines in relation to our facilities in RTP, North Carolina and are required to operate pursuant to certain permits.

Table o f Contents

Our present and future business has been and will continue to be subject to various other laws and regulations.

Various laws, regulations and recommendations relating to data privacy and protection, safe working conditions, laboratory practices, the experimental use of animals and the purchase, storage, movement, import, export and use and disposal of hazardous or potentially hazardous substances, including radioactive compounds and infectious disease agents, used in connection with our research work are or may be applicable to our activities.

Laws, regulations and recommendations relating to data privacy and protection, safe working conditions, laboratory practices, the experimental use of animals and the purchase, storage, movement, import, export and use and disposal of hazardous or potentially hazardous substances, including radioactive compounds and infectious disease agents, used in connection with our research work are or may be applicable to our activities.

Certain agreements entered into by us involving exclusive license rights may be subject to national or international antitrust regulatory control, the effect of which cannot be predicted.

The extent of government regulation, which might result from future legislation or administrative action, cannot accurately be predicted.

The European Parliament and the Council of the E.U.

Regulators currently impose data privacy and security requirements, which include monetary fines for privacy violations.

For example, the European Parliament and the Council of the E.U.

adopted a comprehensive GDPR in 2016 to replace the current E.U.

5 unchanged sentences

In addition, several U.S.

jurisdictions have similar data privacy laws, such as the California Consumer Privacy Act and California Privacy Rights Act.

jurisdictions have similar data privacy laws, such as the CCPA and California Privacy Rights Act.

MANUFACTURING

We seek to ensure an uninterrupted supply of medicines to patients around the world.

To that end, we continually review our manufacturing capacity, capabilities, processes and facilities.

To that end, we regularly review our manufacturing capacity, capabilities, processes and facilities.

We believe that our manufacturing facilities, together with the third-party contract manufacturing organizations we outsource to, currently provide sufficient capacity for our products and to Samsung Bioepis, our collaboration partner that develops, manufactures and markets biosimilar products, and other strategic contract manufacturing partners.

In the fourth quarter of 2021 we began construction of a new gene therapy manufacturing facility in RTP, North Carolina to support our gene therapy pipeline across multiple therapeutic areas.

The new manufacturing facility will be approximately 197,000 square feet with an estimated total investment of approximately $195.0 million.

In the fourth quarter of 2021 we began construction of a new gene therapy, clinical packaging and other manufacturing facility in RTP, North Carolina to support our gene therapy pipeline across multiple therapeutic areas.

We estimate the construction of this manufacturing facility will be completed during 2025.

As we continue to advance our research and development prioritization efforts, which includes refocusing our investment in gene therapy, we are evaluating several alternative uses for this facility.

T able of Contents

MANUFACTURING FACILITIES

4 unchanged sentences

* Other includes products manufactured for contract manufacturing partners.

** We began manufacturing TYSABRI at the Solothurn manufacturing facility in 2024.

In addition to our drug substance manufacturing facilities, we have a drug product manufacturing facility and supporting infrastructure in RTP, North Carolina, including a parenteral facility and an oral solid dose products manufacturing facility.

1 unchanged sentence

The oral solid dose products facility can supplement our outsourced small molecule manufacturing capabilities.

We also have an oligonucleotide synthesis manufacturing facility in RTP, North Carolina.

This facility gives us the capability to manufacture both commercial and clinical ASO's and beginning in 2024 this facility will manufacture SPINRAZA.

Table o f Contents

We have an oligonucleotide synthesis manufacturing facility in RTP, North Carolina.

This facility gives us the capability to manufacture both commercial and clinical ASOs, including QALSODY, and beginning in 2025 this facility will manufacture SPINRAZA.

In order to support our future growth and drug development pipeline, we built a large-scale biologics manufacturing facility in Solothurn, Switzerland.

In the second quarter of 2021 a portion of the facility (the first manufacturing suite) received a GMP multi-product license from the SWISSMEDIC and was placed into service.

The second manufacturing suite became operational in January 2024.

Solothurn has been approved for the manufacture of ADUHELM and LEQEMBI by the FDA.

Genentech is responsible for all worldwide manufacturing activities for bulk RITUXAN, RITUXAN HYCELA and GAZYVA and has sourced the manufacture of certain bulk RITUXAN, RITUXAN HYCELA and GAZYVA requirements to a third party.

Alkermes currently supplies both VUMERITY and FAMPYRA to us pursuant to separate supply agreements.

In October 2019 we entered into a new supply agreement and amended our license and collaboration agreement with Alkermes for VUMERITY.

We have elected to initiate a technology transfer and, following a transition period, to manufacture VUMERITY or have VUMERITY manufactured by a third party we have engaged in exchange for paying an increased royalty rate to Alkermes on any portion of future worldwide net commercial sales of VUMERITY that is manufactured by us or our designee.

In January 2023 we entered into a new supply agreement with Alkermes for FAMPYRA through January 2025.

In December 2023 Alkermes entered into a definitive agreement to sell its development and manufacturing facility to Novo Nordisk, which is expected to close in mid-2024.

Alkermes and Novo Nordisk plan to enter into subcontracting arrangements to continue work currently performed at the facility for a period of time after closing the transaction, which may continue through the end of 2025.

In the second quarter of 2021 a portion of the facility (the first manufacturing suite) received a GMP multi-product license from SWISSMEDIC and was placed into service.

The second manufacturing suite, which was also licensed to operate by SWISSMEDIC, became operational in the first quarter of 2024.

Solothurn has been approved for the manufacture of LEQEMBI.

Genentech is responsible for all worldwide manufacturing activities for bulk RITUXAN, RITUXAN HYCELA and GAZYVA and has sourced the manufacture of certain bulk requirements to a third party.

THIRD-PARTY SUPPLIERS AND MANUFACTURERS

We principally use third parties to manufacture the active pharmaceutical ingredient and the final product for our small molecule products and product candidates, including TECFIDERA and FUMADERM, and the final drug product for our large molecule products and, to a lesser extent, product candidates.

We principally use third parties to manufacture the active pharmaceutical ingredient and the final product for our small molecule products and product candidates, including TECFIDERA, VUMERITY and FUMADERM, and the final drug product for our large molecule products and, to a lesser extent, product candidates.

We source the majority of our fill-finish and all of our final product assembly and storage operations for our products, along with a substantial part of our label and packaging operations, to a concentrated group of third-party contract manufacturing organizations.

Raw materials, delivery devices, such as syringes and auto-injectors, and other supplies required for the production of our products and product candidates are procured from various third-party suppliers and manufacturers in quantities adequate to meet our needs.

Continuity of supply of such raw materials, devices and supplies is assured through inventory management and dual sourcing as appropriate.

Our third-party service providers, suppliers and manufacturers may be subject to routine cGMP inspections by the FDA or comparable agencies in other jurisdictions and undergo assessment and certification by our quality management

T able of Contents

In addition, one of our contract manufacturers for IMRALDI and BENEPALI entered into a proposed acquisition by a third party, which is expected to close at the end of 2024.

We are currently evaluating the impact this will have on our biosimilars business.

ESG AND CLIMATE-RELATED MATTERS

We continue to refine our ESG strategy and programs so they are designed to deliver meaningful results in the areas where we believe we can have the greatest impact.

We have bolstered our efforts in access and health equity and refocused our Foundation efforts on the communities where we operate.

We endeavor to assure continuity of supply of such raw materials, devices and supplies through inventory management and dual sourcing as appropriate.

In addition, one of our contract manufacturers for IMRALDI and BENEPALI was acquired by a third party in December 2024.

We have evaluated the impact this will have on our biosimilars business and have mitigation activities in progress designed to ensure supply continuity.

CORPORATE RESPONSIBILITY

Our Corporate Responsibility strategy and programs are designed to deliver meaningful results in the areas where we believe we can have the greatest impact.

We have bolstered our efforts in access and health equity and refocused our Biogen Foundation efforts in the communities where we operate and to help deliver better health.

Our environmental strategy is designed to balance impact in line with investment and to drive sustainability into our core operations.

ESG oversight is formally embedded into our Board of Director's corporate governance principles and our Board of Directors annually review our ESG strategy and short-and long-term goals.

We regularly review our environmental commitments within the context of our business performance, rising costs and supply chain challenges.

Corporate Responsibility oversight is formally embedded into our Board of Directors' corporate governance principles.

Our Board of Directors annually reviews our Corporate Responsibility strategy, progress and goals.

We also regularly review our environmental commitments within the context of our business performance and external challenges.

We remain committed to engaging employees and suppliers.

As part of our broader commitment to these priorities, we continue to tie a portion of our employees' and executive officers' compensation to advancing our ESG efforts.

We strive to comply in all material respects with applicable laws and regulations concerning the environment.

While it is impossible to predict accurately the future costs associated with environmental compliance and potential remediation activities, compliance with environmental laws is not currently expected to require significant capital expenditures and has not had, and is not expected to have, a material adverse effect on our operations or competitive position.

As part of our broader commitment to these priorities, we continue to tie a portion of our employees' and executive officers' compensation to advancing our Corporate Responsibility priorities.

Our Executive Committee has responsibility for evaluating the impact of climate change on the business and overseeing actions taken by the company to limit its adverse impact on the environment.

Our ERM framework is designed to ensure climate-related risks and opportunities are integrated into our overall business strategy.

Our ERM team monitors strategic climate-related risks across all aspects of our business and utilizes climate scenarios as part of its assessments.

The ERM team evaluates identified risks, including any climate-related physical and transitional risks, by engaging leaders across the company.

RISK MANAGEMENT

Addressing ESG matters is part of our long-term global strategy and investment in our future and we have seen increased interest from stakeholders and investors on our ESG practices.

While we continue to advance our ESG efforts, there is no certainty that we will manage ESG matters in ways that successfully meet rapidly changing expectations from investors, regulators, third party rankings firms, customers and society as a whole.

Our inability to manage ESG matters in accordance with expectations can negatively impact our reputation and business.

Our Board of Directors believes that a fundamental part of risk management is identifying and understanding the risks we face, monitoring these risks and adopting appropriate controls and mitigation of such risks.

Our Board of Directors and its committees are responsible for reviewing our risk framework and governance and management's exercise of its responsibility to assess, monitor and manage our significant risk exposures.

Our Board of Directors oversees an enterprise-wide approach to risk management, which is designed to support execution of our strategy and achievement of our objectives to improve long-term operational and financial performance and enhance stockholder value.

Table o f Contents

We have a company-wide ERM program to identify, mitigate and monitor enterprise-level risks that may affect our ability to achieve our objectives.

The ERM program is overseen by our ERM Committee, a cross-functional group of business leaders representing all of our key business functions.

On an ongoing basis, we evaluate the greatest risks to our business, their underlying risk drivers and the associated mitigation activities and controls.

CLIMATE RISK MANAGEMENT

We believe that the areas of risk that are fundamental to the success of our enterprise and rise to enterprise-level risks includes, among other things, environmental matters.

Our ERM framework is designed to ensure climate-related risks and opportunities are monitored and integrated into our overall business strategy.

Our ERM process includes evaluating identified risks, including any climate-related physical and transition risks, by engaging leaders across the company.

We identify climate risk as the risk of loss arising from climate change which comprises both physical risk and transition risk.

2 unchanged sentences

Disruption in supply chains, changing customer expectations in the biosimilars market and potential shifts in the regulatory environment that disadvantage the use of fossil fuels, PFAS or other materials may make it difficult for us to fulfill business obligations or cause us to incur substantial expense.

Identified climate-related material risks and opportunities are reported to our ERM team, which reports to our Executive Committee and Board of Directors.

We consider and address those risks and opportunities that are financially material and may impact our business model, as well as mitigation measures that are in place or need to be adopted.

Identified climate-related material risks and opportunities are reported to our ERM team, which reports to our ERM Committee with oversight by our Board of Directors.

We endeavor to consider and address those risks and opportunities that are financially material and may impact our business model, as well as mitigation measures that are in place or need to be adopted.

For additional information on our environment-related risks, please read Item 1A.

Risk Factors included in this report.

T able of Contents

CALIFORNIA CLIMATE LEGISLATION

In October 2023 California signed into law the CCDAA and the CRFRA.

These new environmental disclosure laws will each impose additional climate-related reporting requirements on large companies conducting business in the state of California.

Beginning in 2026 the CCDAA will require companies meeting certain revenue thresholds to publicly disclose Scope 1 and Scope 2 GHG emissions for the prior fiscal year.

Starting in 2027 companies meeting certain revenue thresholds will also need to publicly disclose Scope 3 GHG emissions for the prior fiscal year.

Assurance requirements will also apply to these public disclosures and will be phased-in over time.

The CRFRA will require companies meeting certain revenue thresholds to prepare biennial reports disclosing climate-related financial risk, as well as mitigation measures the company has adopted to reduce this risk.

The first climate-related financial risk reports are due by January 1, 2026.

We expect to be required to comply with both the CCDAA and CRFRA and are actively evaluating the requirements under these acts in order to prepare for compliance.

At this time, we expect we may incur additional costs associated with these new laws, including costs associated with implementing or updating existing controls and procedures to collect and maintain required data, as well as costs associated with retaining third-party assurance providers.

CLIMATE-RELATED DISCLOSURES

We monitor global climate-related disclosure requirements to prepare for reporting, progress activities and publish materials designed to ensure our compliance under applicable laws and regulations.

The E.U., California and certain other countries in which we do business have enacted legislation and regulations to enhance disclosures related to the impacts of climate-related matters.

The E.U.'s Corporate Sustainability Reporting Directive will require expansive disclosures on various environmental and social matters for companies whose business and assets exceed certain thresholds within E.U.

California's environmental disclosure laws will impose additional climate-related reporting requirements on large companies conducting business in the state of California.

HUMAN CAPITAL

2 unchanged sentences

and approximately 3,350 employees were employed in foreign countries.

DIVERSITY, EQUITY AND INCLUSION

At Biogen, prejudice, racism and intolerance are unacceptable.

We are committed to DE&I across all aspects of our organization, including recruitment, hiring, promotion, retention and development practices.

As of December 31, 2023, 31.2% of Biogen’s manager-level and above positions were held by ethnic or racial minorities in the U.S.

Our policies and practices are global, but the laws in many countries outside the U.S.

do not permit us to collect ethnic or racial data on our employees.

Globally, 48.6% of Biogen’s positions at director-level and above were held by women as of December 31, 2023.

Our DE&I strategy outlines what we believe to be actionable steps to deepen our commitment across the business, building upon a strong foundation.

This plan includes the strategy to build our talent and strengthen our leadership, improve health outcomes for underserved communities in the disease areas we treat and contribute to the communities impacting our employees and patients.

We plan to create greater awareness and capability in our organization through leadership accountability and transparency.

We are honored to be recognized as an employer of choice.

For the sixth consecutive year, we scored 100% on the Disability:IN's Disability Equality Index, which measures our policies and practices related to disability inclusion.

Additionally, for the fourth consecutive year, we were awarded the DI-NC Employer Award by Disability:IN North Carolina for our commitment to champion and invest in disability inclusion at the affiliate and national levels.

For the tenth consecutive year, we were recognized as a Best Place to Work for LGBTQ+ Equality by the Human Rights Campaign, scoring 100% on their Corporate Equality Index.

STRENGTHENING OUR GLOBAL COMPETENCY

We are committed to strengthening the DE&I awareness and capability of our employees.

We have focused on giving our employees the resources and learning they need to contribute to our strategy.

Our people managers are trained on inclusive recruiting and hiring and our global employees are trained on DE&I curriculum.

In 2022 we introduced GlobeSmart®, a tool to enhance cross-cultural collaboration, increase cultural agility and further connect our global teams.

Our people leaders have used GlobeSmart®, allowing them to explore different working styles, perspectives and approaches that exist around the globe, getting actionable, personalized advice for better collaboration and teamwork across cultures, and exploring new ways for teams to build trust, strengthen collaboration and leverage diversity.

PHILOSOPHY ON PAY EQUITY

We are committed to providing our employees with equal pay for equal work.

As of December 31, 2024, 30.9% of Biogen’s U.S.

manager-level and above positions were held by ethnic or racial minorities.

Globally, 48.3% of Biogen’s positions at the director-level and above were held by women as of December 31, 2024.

CULTURE AND ENGAGEMENT

Our values and merit-based culture guide every action we take, from pioneering new therapies to promoting health access for all patients.

To continue to build on our strong culture, we implemented the New Biogen Way, aimed at maintaining our spirit of innovation and patient-centricity while advancing a more entrepreneurial business mindset and results-focused approach.

These are the essentials that are designed to work together to help us successfully achieve our mission:

Table o f Contents

We boldly advance rigorous science to drive innovation in medicine.

Think broadly:

We are humble and curious, integrating external and internal advancements to successfully compete.

Drive results:

We achieve high performance and have a greater impact by being decisive and solution-oriented, while effectively managing risk.

We act with the highest integrity with each other and all who place their trust in us.

We are open and embrace and leverage differences, as well as treat everyone with care and dignity.

We use an employee survey program to understand employee engagement, giving employees an opportunity for feedback.

The survey is designed to empower managers and leaders with anonymous information on their practices related to building culture, performance and an engaged workforce, allowing them to create plans and measure efficacy for continuous improvement.

We care about employee feedback and are building an analytics community across Human Resources to bring more rigor and sophistication to the collection and analysis of employee opinions.

We use those employee perspectives to guide us to take actions that are designed to improve engagement and support and help maintain our reputation as a great place to work for all our employees.

GLOBAL COMPETENCY

Many factors influence employee success and well-being.

We work to foster a workplace to allow employees to deliver on our shared mission.

From career development to wellness to workplace environment, there are many opportunities to meet employee needs, and to build a workplace where people are empowered to learn, grow and build rewarding careers.

Our employees are encouraged to take advantage of an array of professional development resources.

Managers are trained to coach employees for performance, and to engage in employee development discussions to support growth and learning.

Opportunities for ongoing learning can contribute to employee engagement and success.

Development occurs through on-the-job learning, challenging new assignments, leadership development programs, instructor-led training, online learning, mentoring and more.

With some employees continuing to work from home, virtual learning plays a key role.

Virtual learnings are available through Biogen University as well as Coursera.

To create and sustain an inclusive workplace reflective of the patients we serve, we offer programs that invest in our talent pipeline and in our current leaders, including:

• Global Leadership Summit:

Immersing leaders in topics designed to help them shape culture and build resilience.

• Advance Your Leadership Potential:

Preparing high-potential individual contributors for first-level leadership roles.

• Executive Coaching:

Coaching program available to support individuals as they work toward enhancing their impact in the organization.

SUCCESSION PLANNING

Each year we conduct a talent review across our global enterprise that includes, among other important topics, a review of succession plans for many of our roles.

To help ensure the long-term continuity of our business, we actively manage the development of talent to fill the roles that are most critical to the ongoing success of our Company.

In addition, each year our Board of Directors reviews the succession plan for our executives.

COMPENSATION AND BENEFITS

Our approach to employee compensation and benefits is designed to deliver merit-based cash, equity and benefit programs that are competitive with those offered by leading companies in the biotechnology industry, and to attract, motivate and retain talent to build a strong, engaged and productive workforce that is equipped to deliver forward-looking business priorities.

We establish components and ranges of compensation based on market and benchmark data.

Within this context, we strive to pay all employees equitably within a reasonable range, taking into consideration factors such as role;

internal equity;

Within this context, we strive to pay all employees fairly within a reasonable range, taking into consideration factors such as role;

job location;

1 unchanged sentence

and individual, business unit and company performance.

In addition, we are committed to

T able of Contents

providing flexible benefits designed to allow our diverse global workforce to have reward opportunities that meet their varied needs so that they are inspired to perform their best on behalf of patients and stockholders each day.

We regularly review our compensation practices and analyze the equity of compensation decisions, for individual employees and our workforce as a whole.

We institute measures, such as communications and trainings, to recognize, interrupt and prevent bias in hiring, performance management and compensation decisions and we provide resources to further develop managers and leaders to help them make equitable decisions about pay.

In addition, we are committed to providing flexible benefits designed to allow our global workforce to have reward opportunities that meet their varied needs so that they are inspired to perform their best on behalf of patients and stockholders each day.

We regularly review our compensation practices and analyze the fairness of compensation decisions, for individual employees and our workforce as a whole.

Table o f Contents

RECRUITMENT AND RETENTION

We seek to recruit and retain highly qualified employees.

A business-wide priority is to strengthen our culture and the employee experience.

To address a highly dynamic labor market, we have examined our global benefits and seek to provide competitive comprehensive total rewards to our employees.

We have also conducted an affordability analysis to benchmark whether our benefits program costs are equitable.

We examined employee total rewards across four pillars:

We believe our wellness initiatives and flexible work arrangements empower employees, increasing workplace satisfaction and allowing us to retain and attract key talent.

We examine employee total rewards across four pillars:

physical, financial, emotional and social well-being.

We continue to evolve our programs to meet our employees’ health and wellness needs, which we believe is essential to attract and retain employees of the highest caliber.

We have refreshed our flexible working arrangement policies to allow for more flexibility around work hours to help employees balance the demands of their work and home lives, shifted many of our on-site wellness services to virtual, including virtual behavior health, nutrition, fitness and overall well-being classes and counseling, provided financial planning workshops, expanded our caregiver services and provided additional holidays and time off for recharging, voting and volunteering.

SUCCESSION PLANNING

Each year we conduct a talent review across our global enterprise that includes, among other important topics, a review of succession plans for many of our roles.

To help ensure the long-term continuity of our business, we actively manage the development of talent to fill the roles that are most critical to the ongoing success of our Company.

In addition, each year our Board of Directors reviews the succession plan for our executives.

TALENT AND DEVELOPMENT

Many factors influence employee success and well-being.

We work to foster a workplace to allow employees to deliver on our shared mission while helping to mitigate their challenges.

Our employees are encouraged to take advantage of an array of professional development resources.

Managers are trained to coach employees for performance, and also engage in employee development discussions to support growth and learning.

Opportunities for ongoing learning can contribute to employee related engagement and success.

At Biogen, development occurs through on-the-job learning, challenging new assignments, formal training, online learning, mentoring and more.

With many employees continuing to work from home, virtual learning plays a key role.

Virtual learnings are available through Biogen University as well as LinkedIn Learning.

Through Biogen University we offer more than 1,000 instructor-based courses, of which approximately 200 are available virtually.

Through LinkedIn Learning we provided employees with access to more than 22,000 on-demand learning modules in 13 languages.

To create and sustain a workplace as diverse and inclusive as the patients we serve, we offer programs that invest in our talent pipeline and in our current leaders, including:

• Activate, Reflect and Co-Create:

Preparing top talent for the rigors of executive roles.

• Women’s Leadership Program:

Addressing the unique challenges faced by female leaders to increase influence and impact.

• Executive Leadership Retreat:

Immersing leaders in topics designed to help them shape culture and build resilience.

• The Partnership, Inc's BioDiversity Fellows Program:

To continue to bolster our talent pipeline with a diverse mix of leaders, high potential, mid-career, underrepresented minorities participate in this program, which we helped create.

• Women on the Rise:

Addressing the unique challenges faced by mid-level female leaders to increase influence and impact.

• Emerging Leaders:

Preparing high-potential individual contributors for first-level leadership roles.

T able of Contents

Coaching program available to support individuals as they work toward enhancing their impact in the organization.

Our ERNs provide invaluable opportunities for employees to share knowledge and build connections.

Our current ERNs include:

• Parenting Network Group:

Biogen's newest ERN provides support, networking and development opportunities to working parents and caregivers, as well as helping employees navigate the challenges of work-life balance.

Brings together early-career professionals and their advocates.

We regularly assess our global benefits, and we believe we remain competitive with other companies in terms of comprehensive total rewards.

We also conduct affordability analyses to benchmark whether our benefits program costs are appropriate and fair.

Our total rewards program is designed to meet the needs of employees in local markets and includes retirement savings plans, financial advising, LTI plans and incentive grants, company-paid life insurance and disability coverage, tuition reimbursement and college-planning services.

Our global employee assistance program provides support to all employees and their family members worldwide.

WORKPLACE HEALTH AND SAFETY

The safety and well-being of our employees is a priority for Biogen, and we believe every employee plays a role in creating a safe and healthy workplace.

Our employees have varied roles and functions, which is why we empower them to promote a safe working environment, regardless of whether work happens in the lab, in an office or in a manufacturing facility.

Our EHS policies and practices are intended to protect not only our employees, but also the surrounding communities where we operate.

We maintain an EHS management system, which documents our health and safety management practices, including the following elements:

• risk and opportunity assessments to identify what could cause harm in the workplace;

• prioritization and integration of action plans with quantified targets to address those risks;

• integration of actions to prepare for and respond to emergency situations;

• evaluation of progress in reducing/preventing health issues/risks against targets;

• procedures to investigate work-related injuries, ill health, diseases and incidents;

• training to employees and contractors to raise awareness and reduce operational health and safety incidents.

We have also introduced safety criteria in our procurement and contractual requirements.

OUR CULTURE OF INCLUSION

We are committed to merit-based opportunities and believe discrimination is unacceptable.

We believe an inclusive workplace fosters innovation and helps us to better support patients.

Our strategy outlines steps to build our talent and strengthen our leadership, improve health outcomes for patients in the disease areas we treat and contribute to the communities where we live and work.

Our ERGs are formed by interested employees and sponsored by a senior leader of the company.

Membership of each ERG is open to all employees.

Our ERGs provide opportunities for employees to build connections, foster leadership development and cultivate a sense of belonging.

Our current ERGs include:

• AccessAbility:

Supports employees with disabilities and employees who are caretakers of individuals with disabilities.

Supports employees with disabilities and employees who are caregivers of individuals with disabilities and their allies.

• Biogen Veterans Network:

Encourages veterans and allies of veterans to connect and support one another.

Fosters awareness and appreciation of different cultural backgrounds, in addition to promoting networking and development opportunities for members.

Supports a best-in-class working environment for LGBTQ+ employees and embraces all LGBTQ+ employees and their allies.

• Women’s Innovation Network:

Encourages veterans and allies to connect and support one another.

Brings together early-career professionals and their allies.

Fosters awareness and appreciation of different cultural backgrounds, in addition to promoting networking and development opportunities for employees.

Addresses environmental issues at work, in employees' personal lives and in the communities where we live and work.

• Parenting Network Group:

Provides support, networking and development opportunities to working parents and caregivers, as well as helping employees navigate the challenges of work-life balance.

Brings together LGBTQ+ employees and their allies.

• Women’s Impact Network:

Creates networking, mentoring and learning opportunities for women and allies worldwide.

Advances climate, health and equity at work, in employees' personal lives and in the communities where we live and work.

CULTURE AND ENGAGEMENT

We utilize an employee survey program to pulse employees through email and mobile apps as well as provide an opportunity for commentary and facilitate feedback to questions.

We care deeply about employee feedback and are building an analytics community across Human Resources to bring more rigor and sophistication to the collection and analysis of employee opinions.

We use their perspectives to guide us to take actions that improve engagement and support and help maintain our reputation as a great place to work for all our employees.

WORKPLACE HEALTH AND SAFETY

The well-being of our employees is the priority, and we believe every employee plays a role in creating a safe and healthy workplace.

Our policies and practices are intended to protect not only our employees, but also the surrounding communities where we operate.

In 2023 we continued to make significant progress integrating Human Performance into our Environment, Health and Safety programs.

We believe that, when it comes to safety, workers are part of the solution.

We encourage employees to collaboratively engage in proactive problem solving through practices such as Open Reporting and Work Observation and Risk Conversations.

Additionally, our physical safety program focused on detailed evaluations of critical tasks that could expose employees to serious injury or fatality if controls are absent or not used.

The actions we implement as a result of these evaluations reduce the risks associated with these essential activities and ensure our operational systems are safer and more resilient for employees.

We also use “After Action Reviews” following the completion of a project.

These reviews enable us to not only focus on areas for improvement, but also to learn and apply good practices from what goes well.

By engaging and empowering our employees through such programs, we believe that we can help change how the entire industry approaches safety performance and risk management.

T able of Contents

Table o f Contents

INFORMATION ABOUT OUR EXECUTIVE OFFICERS (as of February 12, 2025)

3 unchanged sentences

Alexander Executive Vice President, Chief Legal Officer 68 2006

McDonnell Executive Vice President and Chief Financial Officer 60 2020

McDonnell (1)

Executive Vice President and Chief Financial Officer 61 2020

Nicole Murphy Executive Vice President, Pharmaceutical Operations and Technology 52 2015

8 unchanged sentences

Executive Vice President, Head of Corporate Development 48 2023

Kramer Senior Vice President, Chief Accounting Officer 58 2018

Senior Vice President, Chief Accounting Officer 59 2018

(1) Michael R.

McDonnell, Executive Vice President and Chief Financial Officer, plans to retire from Biogen on March 1, 2025.

McDonnell's retirement, Robin C.

Kramer, currently Senior Vice President and Chief Accounting Officer at Biogen, will assume the role of Executive Vice President and Chief Financial Officer.

Christopher A.

25 unchanged sentences

l Boston University School of Law, J.D.

T able of Contents

Table o f Contents

McDonnell has served as our Executive Vice President and Chief Financial Officer since August 2020.

35 unchanged sentences

l The George Washington University, Ph.D.

T able of Contents

Table o f Contents

Izzar has served as our Executive Vice President, Head of Global Product Strategy and Commercialization since July 2021.

24 unchanged sentences

Jane Grogan, Ph.D.

Grogan has served as our Executive Vice President and Head of Development since September 2023.

Grogan has served as our Executive Vice President and Head of Development since October 2023.

Grogan most recently served as the Chief Scientific Officer at Graphite Bio from 2021 to 2023 and ArsenalBio from 2019 to 2021, both cell and gene therapy companies.

4 unchanged sentences

l University of Melbourne, B.Sc in Biochemistry and Pharmacology

T able of Contents

Table o f Contents

Adam Keeney, Ph.D.

22 unchanged sentences

She is a member of the Massachusetts Society of CPAs and the American Institute of CPAs.

Kramer currently serves on the board of directors of the Center for Women and Enterprise.

Kramer previously served as a Board Member for the Massachusetts State Board of Accountancy from September 2011 to December 2015 and Probus Insurance Company Europe DAC from 2016 to 2018.

Kramer previously served as a Board Member for the Center for Women & Enterprise from August 2020 to November 2024, the Massachusetts State Board of Accountancy from September 2011 to December 2015 and Probus Insurance Company Europe DAC from 2016 to 2018.

Public Company Boards

l Armata Pharmaceuticals, Inc., a biotechnology company

l Salem State University, B.B.A.

T able of Contents

l Salem State University, Bachelor of Science in Business Administration, Accounting

Table o f Contents

AVAILABLE INFORMATION

9 unchanged sentences

None of the information on our website is incorporated into this report.

T able of Contents

Table o f Contents

Compared sentence by sentence after normalising whitespace, quotation marks, case and digits, so re-formatting and restated figures do not read as changed language. Wording changes appear as one removal and one addition. The current filing and the prior one are authoritative.

What changed 10-K

Item 1. Business