BIOGEN INC. (BIIB) Business

ITEM 1. BUSINESS

OVERVIEW

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. We market the first and only drug approved in the U.S., the E.U. and certain international markets 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, external collaborations and acquisitions.

Our marketed products include VUMERITY, TYSABRI, TECFIDERA, AVONEX and PLEGRIDY for the treatment of MS; SPINRAZA for the treatment of SMA; SKYCLARYS for the treatment of FA; and QALSODY for the treatment of ALS.

We also have collaborations with Eisai on the commercialization of LEQEMBI for the treatment of Alzheimer's disease and Supernus 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; GAZYVA for the treatment of CLL, follicular lymphoma and, following its approval in October 2025, lupus nephritis; OCREVUS for the treatment of PPMS and RMS; LUNSUMIO for the treatment of relapsed or refractory follicular lymphoma; COLUMVI, a bispecific antibody for the treatment of non-Hodgkin's lymphoma; 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.

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

KEY BUSINESS DEVELOPMENTS

The following is a summary of key developments affecting our business since the beginning of 2025.

ACQUISITIONS

ALCYONE THERAPEUTICS, INC.

In November 2025 we completed the acquisition of all of the issued and outstanding shares of Alcyone Therapeutics, Inc., a clinical-stage biotechnology company focused on pediatric care through precision CNS therapeutics and dosing platforms. Alcyone's lead asset is ThecaFlex DRx, an implantable subcutaneous port and catheter device being investigated for the intrathecal delivery of ASOs, including SPINRAZA, which is designed to provide an alternative to repeat lumbar punctures in chronic intrathecal administration of medicines.

Total consideration for this transaction, which was recorded in acquired in-process research and development, upfront and milestone expense in our consolidated statements of income for the year ended December 31, 2025, was approximately $85.0 million, comprising a $50.0 million payment made upon closing and a $35.0 million payment that was considered probable as of December 31, 2025, and made upon FDA approval of a supplemental application in January 2026.

We may pay additional development and regulatory milestone payments to the former shareholders of Alcyone of up to a total of $75.0 million if approval is received for ThecaFlex DRx administration of SPINRAZA or other additional pipeline products.

We accounted for this transaction as an asset acquisition as the value being acquired primarily relates to a single asset. Under the terms of this acquisition, we will oversee the end-to-end development, manufacturing and commercialization of ThecaFlex DRx.

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

COLLABORATIVE AND OTHER RELATIONSHIPS

DAYRA THERAPEUTICS, INC. COLLABORATION

In October 2025 we entered into a research collaboration with Dayra to discover and develop oral macrocyclic peptides for priority targets in immunological conditions.

Under the terms of this agreement, both companies will collaborate to identify, validate and optimize oral macrocycle candidates for high-priority immunological targets, with our company advancing the molecules through further development and potential commercialization, including manufacturing.

In connection with the closing of this transaction we made an upfront payment of $50.0 million to Dayra, which was recognized in acquired in-process research and development, upfront and milestone expense within our consolidated statements of income for the year ended December 31, 2025.

This agreement also provides us with the option to acquire the development candidates from Dayra, subject to additional payments per program. Dayra will also be eligible to receive potential preclinical and clinical development milestone payments per program.

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

VANQUA BIO, INC. COLLABORATION

In October 2025 we entered into a license agreement with Vanqua granting us exclusive worldwide rights to further develop, manufacture and commercialize Vanqua's preclinical oral C5aR1 antagonist compound.

In connection with the closing of this transaction we made an upfront payment of $70.0 million to Vanqua, which was recognized in acquired in-process research and development, upfront and milestone expense within our consolidated statements of income for the year ended December 31, 2025.

We may pay Vanqua potential development, regulatory or commercial, and sales milestone payments of up to $135.0 million, $295.0 million and $560.0 million, respectively, if all the specified milestones set forth in this collaboration are achieved. In addition, we may pay Vanqua tiered royalties on potential net sales of any licensed product under this collaboration in the mid-single digit to low-double digit percentages.

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

CITY THERAPEUTICS, INC. COLLABORATION

In May 2025 we entered into a strategic research arrangement with City Therapeutics to develop select novel RNAi therapies. Through this arrangement, City Therapeutics will leverage its next-generation RNAi engineering technologies to develop an RNAi trigger molecule (or molecules) combined with our proprietary drug delivery technology. The collaboration will initially focus on a single target that mediates key CNS diseases, utilizing tissue enhanced delivery technologies with the aim of allowing for systemic administration of medicines. We will be responsible for IND-enabling studies and global clinical development along with any regulatory submissions and all activities related to commercialization, including manufacturing.

In connection with the closing of this transaction we made an upfront payment of $16.0 million to City Therapeutics, which was recognized in acquired in-process research and development, upfront and milestone expense within our consolidated statements of income for the year ended December 31, 2025, and invested $30.0 million in exchange for a City Therapeutics convertible note, representing a minority equity interest in City Therapeutics, if converted. This convertible note was recorded as a component of investments and other assets within our consolidated balance sheets as of December 31, 2025.

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

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STOKE THERAPEUTICS, INC. COLLABORATION

In February 2025 we entered into a collaboration and license agreement with Stoke to co-develop and commercialize zorevunersen, an investigational ASO that targets the SCN1A gene for the potential treatment of Dravet syndrome, a rare form of genetic epilepsy associated with refractory seizures and neurodevelopmental impairments. Zorevunersen dosed its first patient in August 2025, advancing zorevunersen to a global Phase 3 trial.

Under the terms of this agreement, Stoke will continue to lead global development and retain exclusive development and commercialization rights for zorevunersen in the U.S., Canada and Mexico and we will have exclusive rights to commercialize zorevunersen in the rest of the world.

In connection with the closing of this transaction we made an upfront payment of $165.0 million to Stoke, which was recognized in acquired in-process research and development, upfront and milestone expense within our consolidated statements of income for the year ended December 31, 2025.

We also have an exclusive option to license certain future follow-on ASO products targeting the SCN1A gene in all territories worldwide other than the U.S., Canada and Mexico, in exchange for separate milestone, cost sharing and royalty considerations.

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

ROYALTY PHARMA FUNDING ARRANGEMENT

In February 2025 we entered into a funding agreement with Royalty Pharma under which we received $200.0 million in 2025 and will receive up to $50.0 million in 2026 to co-fund our development costs for the litifilimab program. As there is a substantive transfer of risk to the financial partner for the amount invested, the development funding will be recognized by us as an obligation to perform contractual services. This funding is being recognized as a reduction to research and development expense within our consolidated statements of income, proportionate to the related expense. For the year ended December 31, 2025, we recorded a reduction to research and development expense of $200.0 million within our consolidated statements of income.

If the litifilimab clinical trials are successful for the indications based on the applicable clinical trials, upon regulatory approval in the U.S. or certain major markets in the world, Royalty Pharma will be eligible to receive approval-based fixed milestone payments of up to $250.0 million. The milestone payments due upon approval will be recorded as a component of other (income) expense, net within our consolidated statements of income, when incurred.

If litifilimab receives regulatory approval, Royalty Pharma will be eligible to receive royalties of a mid-single digit percentage of the applicable net sales. Royalties on net sales will be recorded as cost of sales within our consolidated statements of income.

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

DEVELOPMENTS IN KEY COLLABORATIVE RELATIONSHIPS

LEQEMBI (lecanemab)

United States

Key developments related to LEQEMBI in the U.S. consisted of the following:

•In January 2026 the FDA accepted for review the supplemental BLA for LEQEMBI subcutaneous autoinjector, LEQEMBI IQLIK, for weekly starting dose, with a PDUFA action date of May 24, 2026.

•In August 2025 the FDA approved the BLA for LEQEMBI subcutaneous autoinjector, LEQEMBI IQLIK, for weekly maintenance dosing.

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

Rest of World

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

•In January 2026 the BLA for LEQEMBI subcutaneous autoinjector was accepted for review by the NMPA in China.

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•In November 2025 Eisai filed an NDA for LEQEMBI in Japan seeking approval for a subcutaneous autoinjector as a new route of administration to Japan's Pharmaceuticals and Medical Devices Agency.

•In November 2025 the MHRA in the UK approved LEQEMBI monthly IV maintenance dosing for the treatment of early Alzheimer's disease.

•In October 2025 Health Canada issued a Notice of Compliance with Conditions for LEQEMBI for the treatment of adult patients with a clinical diagnosis of mild cognitive impairment or mild dementia due to Alzheimer's disease who are either apolipoprotein E ε4 non-carriers or heterozygotes and who have confirmed amyloid pathology.

•In September 2025 the National Medical Products Administration in China approved LEQEMBI monthly IV maintenance dosing for the treatment of early Alzheimer's disease.

•In September 2025 the Therapeutic Goods Administration of Australia approved LEQEMBI for adults who are either apolipoprotein E ε4 non-carriers or heterozygous carriers.

•In June 2025 we filed a request for arbitration in the International Court of Arbitration of the International Chamber of Commerce seeking adoption of a budget and commercialization plan for the European Territory that allocates commercialization activities to Biogen and Eisai in an equitable fashion taking into account our respective capabilities and provides a meaningful role for each party.

•In April 2025 the EC approved LEQEMBI in the E.U. for the treatment of adult patients with a clinical diagnosis of mild cognitive impairment and mild dementia due to Alzheimer's disease who are apolipoprotein E ε4 non-carriers or heterozygotes with confirmed amyloid pathology.

ZURZUVAE (zuranolone)

•In September 2025 the EC approved ZURZUVAE in the E.U. for the treatment of PPD in adults following childbirth, offering the first and only treatment indicated for PPD in the E.U.

•In August 2025 the Medicines and Healthcare products Regulatory Agency in the U.K. granted marketing authorization for ZURZUVAE for moderate to severe PPD in the U.K.

OTHER KEY DEVELOPMENTS

FELZARTAMAB

•In June 2025 we announced the initiation of dosing in the global Phase 3 PREVAIL study. This study will evaluate the efficacy and safety of the investigational drug felzartamab compared to placebo on proteinuria and preservation of kidney function in adults diagnosed with IgAN. In connection with the initiation of this dosing we paid a $30.0 million milestone payment to MorphoSys in July 2025. Additionally, in June 2025 we announced the initiation of dosing in the global Phase 3 PROMINENT study. This study will evaluate the efficacy and safety of the investigational drug felzartamab compared to tacrolimus in adults diagnosed with PMN.

•In March 2025 we announced the initiation of dosing in the global Phase 3 TRANSCEND study. This study will evaluate the efficacy and safety of the investigational drug felzartamab compared to placebo in adult kidney transplant recipients diagnosed with AMR. In connection with the initiation of this dosing we paid a $35.0 million milestone payment to MorphoSys in April 2025.

SPINRAZA (nusinersen)

•In January 2026 the EC granted marketing authorization for a high dose regimen of SPINRAZA in the E.U. for the treatment of 5q SMA, which is the most common form of the disease and represents approximately 95% of all SMA cases. The high dose regimen is comprised of 50 mg/5 mL and 28 mg/5 mL doses and individuals transitioning from the 12 mg dose will receive one 50 mg dose in place of their next 12 mg dose, followed by 28 mg maintenance doses every four months thereafter.

•In September 2025 the high dose regimen of SPINRAZA was approved by the Ministry of Health, Labour and Welfare in Japan.

•In September 2025 the FDA issued a CRL for the supplemental NDA for a higher dose regimen of nusinersen for the treatment of SMA. The CRL requested an update to the technical information to be included in the Chemistry Manufacturing and Controls module of the supplemental NDA and did not cite any deficiencies in the clinical data of the high dose regimen. We resubmitted the supplemental NDA to the FDA, which has been accepted for review with a PDUFA action date of April 3, 2026.

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SKYCLARYS (omaveloxolone)

•In April 2025 SKYCLARYS was approved by the Medicines and Healthcare products Regulatory Agency in the U.K. and in Brazil. In March 2025 SKYCLARYS was approved by Health Canada.

QALSODY (tofersen)

•In July 2025 the Medicines and Healthcare products Regulatory Agency in the U.K. approved QALSODY for the treatment of ALS in adults who have a mutation in the SOD1 gene.

•In March 2025 Health Canada issued marketing authorization with conditions for QALSODY for the treatment of ALS in adults who have a mutation in the SOD1 gene. The authorization is conditional, pending the results of trials to verify its clinical benefit.

BIIB080

•In April 2025 the FDA granted Fast Track designation to BIIB080, an investigational ASO therapy targeting tau for the potential treatment of Alzheimer's disease.

CORPORATE MATTERS

2025 SENIOR NOTES

On May 12, 2025, we issued senior unsecured notes for an aggregate principal amount of $1.75 billion. In June 2025 we used the net proceeds from the sale of our 2025 Senior Notes to redeem our 4.050% Senior Notes due September 15, 2025, prior to maturity.

For additional information relating to our 2025 Senior Notes, please read Note 13, Indebtedness, to our consolidated financial statements included in this report.

NEW CORPORATE HEADQUARTERS LEASE

In March 2025 we entered into a lease agreement with MIT Investment Management Company and BioMed Realty for the lease of approximately 580,000 square feet of office and research and development space located at 75 Broadway, Cambridge, Massachusetts, which will be used as our new global corporate headquarters, as well as integrating our research and development and technical operations teams alongside our North American commercial organization. As part of a multi-year real estate consolidation plan that is expected to result in a reduction of approximately 40% of our real estate footprint in Massachusetts, this new lease is intended to replace two existing leases, both in Cambridge, Massachusetts, including our current corporate headquarters. We expect the initial lease term of approximately 15.5 years to commence on May 31, 2028.

For additional information on our lease agreement, please read Note 12, Leases, to our consolidated financial statements included in this report.

MANAGEMENT CHANGES

•In March 2025 Robin C. Kramer became Executive Vice President and Chief Financial Officer.

•In March 2025 Sean Godbout became Vice President, Chief Accounting Officer and Global Corporate Controller.

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

PRODUCT AND PIPELINE DEVELOPMENTS

NEUROLOGY

LEQEMBI (lecanemab)

•In December 2025 we and Eisai announced that LEQEMBI has been included in the "Commercial Insurance Innovative Drug List" recently introduced by the National Healthcare Security Administration of China. The Commercial Insurance Innovative Drug List is based on new policies of the Chinese government to support the development and access of innovative medicines.

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•In December 2025 Eisai presented Phase 3 clinical data confirming pharmacological effect of LEQEMBI at the 2025 CTAD conference. The findings represent the results from a large-scale clinical study demonstrating, for the first time, that binding of lecanemab to protofibrils can be measured in cerebrospinal fluid, enabling further understanding of how lecanemab slows Alzheimer's disease progression.

•In July 2025 Eisai announced the interim results of a two-year real-world study of LEQEMBI in the U.S. at the 2025 AAIC conference. The study was conducted to investigate the actual state of real-world clinical treatment with LEQEMBI at 15 medical centers in the U.S., with a final report scheduled for late in the third quarter of Eisai's fiscal year ending March 31, 2026. In this interim study, 83.6% of patients either remained at the same clinical stage or improved from mild dementia to MCI (stable: 76.9%, improvement: 6.7%). Additionally, at time of interim data cut, 86.7% of patients who had received 40 or more doses over 18 months remained stable or showed clinical improvement (stable: 66.7%, improvement: 20%).

RARE DISEASE

ZOREVUNERSEN

•In December 2025 we and Stoke announced new data that further support the potential of zorevunersen, an investigational ASO, as a disease-modifying medicine for Dravet syndrome, at the 2025 American Epilepsy Society Annual Meeting in Atlanta, Georgia. Long-term results from the ongoing Phase 1/2a and OLE studies demonstrated durable seizure reductions, including increases in seizure-free days, in addition to improvements in cognition, behavior and quality of life in patients treated with zorevunersen on top of care anti-seizure medicines.

•In November 2025 we and Stoke announced the publication of final data from the BUTTERFLY study, a prospective, two-year natural history study in people with Dravet syndrome, a severe developmental and epileptic encephalopathy characterized by recurrent seizures and significant and behavioral impairments. The BUTTERFLY study evaluated the impact of Dravet syndrome on adaptive functioning and neurodevelopment over two years in children and adolescents ages 2 to 18 years old. Results showed neurodevelopment plateaued at the developmental age of approximately two years old. Over the two-year study, patients experienced minimal changes in cognitive and behavior, including communication, motor skills and personal skills, compared to typical neurodevelopment expected for children of the same age, and major motor seizure frequency increased by 10.6% over two years.

•In September 2025 we and Stoke announced data from Phase 1/2a and open-label extension studies of zorevunersen that support the potential for zorevunersen to be the first disease-modifying medicine for Dravet syndrome at the 36th International Epilepsy Congress in Lisbon, Portugal. The study showed durable reductions in seizures and continuing improvements in cognition and behavior through three years in patients who continued to receive zorevunersen in the OLE studies. The study also showed substantial increase in seizure-free days and continuous improvement in quality of life demonstrated in patients already taking standard of care anti-seizure medicines.

•In August 2025 we and Stoke announced the first patient dosed in the Phase 3 EMPEROR study of zorevunersen, a potential disease-modifying treatment for Dravet syndrome.

•In July 2025 we and Stoke announced the presentation of data from an analysis that informed the design of the Phase 3 EMPEROR study and evaluated the potential effects of the Phase 3 zorevunersen dosing regimen. The data are complementary to previously reported data from a broader cohort of patients treated with zorevunersen in the Phase 1/2a and OLE studies that showed improvements within the first 9 months and continuing improvements through an additional two years.

SPINRAZA (nusinersen)

•In June 2025 we announced new data that reinforce the clinical impact of nusinersen across a broad spectrum of individuals affected by SMA. These latest findings from Part C of the DEVOTE trial evaluating a higher dose regimen of nusinersen and the NURTURE trial which evaluated the approved 12 mg regimen of SPINRAZA in clinically presymptomatic SMA was presented at the SMA Research & Clinical Care Meeting hosted by Cure SMA. The study showed improvements observed with higher dose regimen of nusinersen in previously treated patient population.

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SALANERSEN (BIIB115)

•In June 2025 we announced positive interim topline results from the Phase 1b study of salanersen, an ASO being developed for the treatment of SMA. Interim Phase 1b data shows children with SMA previously treated with gene therapy experienced a substantial slowing of neurodegeneration and clinically meaningful improvements in motor function following initiation of salanersen. Our Phase 3 registrational study of salanersen is expected to begin in 2026.

SKYCLARYS (OMAVELOXOLONE)

•In June 2025 we announced the initiation of dosing in the global Phase 3 BRAVE study of omaveloxolone in children with FA between the ages of two to sixteen. The BRAVE study will evaluate the efficacy, safety, pharmacokinetics and pharmacodynamics of omaveloxolone in approximately 255 children living with FA.

QALSODY

•In December 2025 the Journal of the American Medical Association Neurology published final results from the completed Phase 3 VALOR study and its OLE study evaluating QALSODY for the treatment of SOD1 ALS with over 3.5 years of follow-up. These results show that early initiation of QALSODY was associated with numerically slower decline in measures of clinical function, breathing and strength, as well as reduction in the risk of death or permanent ventilation. Sustained reductions in neurofilament, a marker of neurodegeneration, further validate the clinical results and demonstrate QALSODY's impact on the underlying biology of SOD1 ALS.

DISCONTINUED PROGRAMS AND STUDIES

SALE OF TOFIDENCE

In March 2025 we completed the sale of our regulatory and commercial rights in the U.S. for TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, to Organon. Under the terms of this transaction, we received a payment of approximately $51.0 million in July 2025 and recognized a de minimis loss within our consolidated statements of income for the year ended December 31, 2025.

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

SALE OF BYOOVIZ AND OPUVIZ RIGHTS

In October 2025 we completed the sale of our remaining commercial rights to two ophthalmology assets in Europe: BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, and OPUVIZ, an aflibercept biosimilar referencing EYLEA. Samsung Bioepis will have full responsibility for commercialization of BYOOVIZ upon the transfer of commercial rights from Biogen back to Samsung Bioepis, which became effective as of January 2026. Under the terms of this transaction, we received a payment of $28.0 million in November 2025 and recognized a minimal gain on disposal within our consolidated statements of income for the year ended December 31, 2025.

BIIB143 (cemdomespib)

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

FELZARTAMAB - LUPUS NEPHRITIS

In November 2025 we discontinued the open label Phase 1b study of felzartamab for the treatment of lupus nephritis.

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MARKETED PRODUCTS

The following graph shows our product revenue, revenue from anti-CD20 therapeutic programs and Alzheimer's collaboration revenue for the years ended December 31, 2025, 2024 and 2023.

(1) MS includes TECFIDERA, VUMERITY, AVONEX, PLEGRIDY, TYSABRI and FAMPYRA. Effective January 1, 2025, our collaboration and license agreement for FAMPYRA global commercialization rights was terminated.

(2) Rare disease includes SPINRAZA, QALSODY, which became commercially available in the E.U. during the second quarter of 2024, and SKYCLARYS which became commercially available in the E.U. during the first quarter of 2024.

(3) Biosimilars includes BENEPALI, IMRALDI, FLIXABI, BYOOVIZ and TOFIDENCE. In 2025 we completed the sale of our rights to TOFIDENCE and BYOOVIZ. For additional information on our arrangements with Samsung Bioepis, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

(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.

(6) Other includes FUMADERM, ADUHELM and ZURZUVAE.

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Product sales for TYSABRI and SPINRAZA each accounted for more than 10.0% of our total revenue for the years ended December 31, 2025, 2024 and 2023. For additional financial information about our product and other revenue and geographic areas where we operate, please read Note 5, Revenue and Note 25, Segment Information, to our consolidated financial statements included in this report and Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations included in this report. A discussion of the risks attendant to our operations is set forth in Item 1A. Risk Factors included in this report.

NEUROLOGY

MULTIPLE SCLEROSIS

We develop, manufacture and market a number of products designed to treat patients with MS. MS is a progressive disease in which the body loses the ability to transmit messages along nerve cells, leading to a loss of muscle control, paralysis and, in some cases, death. Patients with active RMS experience an uneven pattern of disease progression characterized by periods of stability that are interrupted by flare-ups of the disease after which the patient may return to a lower baseline of functioning.

The MS products we market and our major markets are as follows:

ALZHEIMER'S DISEASE

Alzheimer's disease includes LEQEMBI for the treatment of early 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: amyloid plaques and neurofibrillary tangles. 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.

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

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.

NEUROPSYCHIATRY

Neuropsychiatry includes ZURZUVAE for PPD. PPD symptoms are estimated to affect approximately one in eight women who have given birth in the U.S. According to the Centers for Disease Control and Prevention, mental health conditions are the leading cause of maternal mortality with PPD among the most common complications during and after pregnancy.

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

RARE DISEASE

Rare disease includes SPINRAZA for SMA, QALSODY for ALS, which became commercially available in the E.U. during the second quarter of 2024, and SKYCLARYS for FA, which 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. Ultimately, individuals with the most severe type of SMA can become paralyzed and have difficulty performing the basic functions of life, like breathing and swallowing. Due to a deletion or mutations in the SMN1 gene, people with SMA do not produce enough SMN protein, which is critical to the survival of the neurons that control muscles. The severity of SMA correlates with the amount of SMN protein. People with Type 1 SMA, the most severe life-threatening form, produce very little SMN protein and do not achieve the ability to sit without support, and typically do not live beyond two years of age without respiratory support and nutritional interventions. 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.

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.

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. People with ALS experience muscle weakness and atrophy, causing them to lose independence as they steadily lose the ability to move, speak, eat and eventually breathe. Average life expectancy for people with ALS is three to five years from time of symptom onset. Multiple genes have been implicated in ALS. 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 a mutation in the SOD1 gene, and this form of ALS is diagnosed in approximately two percent of all ALS cases.

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Our Rare disease products and major markets are as follows:

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.

BIOSIMILARS

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

Our current biosimilar products and major markets are as follows:

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.

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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 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:

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

PATIENT SUPPORT AND ACCESS

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 transform patients' 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.

We are dedicated to helping patients obtain access to our therapies. Our patient support representatives have access to a comprehensive 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 for qualified commercially insured patients and free product for qualified uninsured or underinsured patients, based on specific eligibility criteria.

We believe all healthcare stakeholders have a shared responsibility to ensure patients have equitable access to new, innovative medicines. We regularly review our pricing strategy and prioritize patient access to our therapies. We have a value-based contracting program designed to align the price of our therapies to the value our therapies deliver

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to patients. 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

SALES FORCE AND MARKETING

We promote our marketed products worldwide, including in the U.S., Europe, Asia, the Middle East and Latin America, primarily through our own sales forces and marketing groups. 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, LUNSUMIO and COLUMVI are marketed by the Roche Group and its sublicensees.

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

We focus our sales and marketing efforts on health care providers in private practice or at major medical centers. We use customary industry practices to market our products and to educate physicians. 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.

DISTRIBUTION ARRANGEMENTS

We distribute our products in the U.S. principally through wholesale and specialty distributors of pharmaceutical products and specialty pharmacies. 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, 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.

Our product sales to two wholesale distributors each accounted for more than 10.0% of our total revenue for the years ended December 31, 2025, 2024 and 2023, and on a combined basis, accounted for approximately 43.9%, 39.3% and 36.9%, respectively, of our gross product revenue. For additional information, please read Note 5, Revenue, to our consolidated financial statements included in this report.

PATENTS AND OTHER PROPRIETARY RIGHTS

Patents are important for obtaining and protecting exclusive rights in our products and product candidates. We regularly seek patent protection in the U.S., the E.U., Asia, the Middle East and Latin America 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.

U.S. 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. 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. Patent and Trademark Office delays in prosecuting the application. In the U.S., under the Drug Price Competition and Patent Term Restoration Act of 1984, commonly known as the Hatch-Waxman Act, a patent that covers a drug approved by the FDA may be eligible for patent term extension (for up to 5 years, but not beyond a total of 14 years from the date of product approval) as compensation for patent term lost during the FDA regulatory review process. The duration and extension of the term of foreign patents vary, in accordance with local law. For example, in a number of European countries, SPCs can be granted to a product to compensate in part for delays in obtaining marketing approval.

Regulatory exclusivity, which may consist of regulatory data protection and market protection, can also provide meaningful protection for our products. Regulatory data protection provides to the holder of a drug or biologic

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marketing authorization, for a set period of time, the exclusive use of the proprietary preclinical and clinical data that it created at significant cost and submitted to the applicable regulatory authority to obtain approval of its product. After the period of exclusive use, third parties are permitted to reference such data in abbreviated applications for approval and to market (subject to any applicable market protection) their generic drugs and biosimilars. Market protection provides the holder of a drug or biologic marketing authorization the exclusive right to commercialize its product for a period of time, thereby preventing the commercialization of another product containing the same active ingredient(s) during that period. Although the World Trade Organization's agreement on trade-related aspects of intellectual property rights requires signatory countries to provide regulatory exclusivity to innovative pharmaceutical products, implementation and enforcement varies widely from country to country.

We also rely upon other forms of unpatented confidential information to remain competitive. We protect such information principally through refraining from public disclosure and utilizing confidentiality agreements with our employees, consultants, outside scientific collaborators, scientists whose research we sponsor and other advisers. In the case of our employees, these agreements also provide, in compliance with relevant law, that inventions and other intellectual property conceived by such employees during their employment are our exclusive property.

Our trademarks are important to us and are generally covered by trademark applications or registrations in the U.S. Patent and Trademark Office and the patent or trademark offices of other countries. We also use trademarks licensed from third parties. Trademark protection varies in accordance with local law, and continues in some countries as long as the trademark is used and in other countries as long as the trademark is registered. Trademark registrations generally are for fixed but renewable terms.

OUR PATENT PORTFOLIO

The following table describes certain patents in the U.S. and Europe that we currently consider of primary importance to our marketed products, including the territory, patent number, general subject matter and expected expiration dates. Except as otherwise noted, the expected expiration dates include any granted patent term extensions and issued SPCs. In some instances, there may be additional later-expiring patents relating to our products directed to, among other things, particular forms or compositions, methods of manufacturing or use of the drug in the treatment of particular diseases or conditions. We also continue to pursue additional patents and patent term extensions in the U.S. 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.

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Footnotes follow on next page.

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(1)In addition to patent protection, certain of our products are entitled to regulatory exclusivity in the U.S. and the E.U. expected until the dates set forth below:

(2)This patent is subject to granted SPCs in certain European countries, which extended the patent term in those countries to 2028.

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

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

(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.

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

(9)SPC applications based on this patent have been filed in certain European countries, which if granted would extend the patent term in those countries to 2032.

The existence of patents does not guarantee our right to practice the patented technology or commercialize the patented product. Patents relating to pharmaceutical, biopharmaceutical and biotechnology products, compounds and processes, such as those that cover our existing products, compounds and processes and those that we will likely file in the future, do not always provide complete or adequate protection. Litigation, interferences, oppositions, inter partes reviews, administrative challenges or other similar types of proceedings are, have been and may in the future be necessary in some instances to determine the validity and scope of certain of our patents, regulatory exclusivities or other proprietary rights, and in other instances to determine the validity, scope or non-infringement of certain patent rights claimed by third parties to be pertinent to the manufacture, use or sale of our products. We also face challenges to our patents, regulatory exclusivities or other proprietary rights covering our products by third parties, such as manufacturers of generics, biosimilars, prodrugs and products approved under abbreviated regulatory pathways. A discussion of certain risks and uncertainties that may affect our patent position, regulatory exclusivities or other proprietary rights is set forth in Item 1A. 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.

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COMPETITION

Competition in the biopharmaceutical industry and the markets in which we operate is intense. There are many companies, including biotechnology and pharmaceutical companies, engaged in developing products for the indications our approved products are approved to treat and the therapeutic areas we are targeting with our research and development activities. Some of our competitors may have substantially greater financial, marketing, research and development and other resources than we do.

We believe that competition and leadership in the industry is based on scientific, managerial and technological excellence and innovation, as well as establishing patent and other proprietary positions through research and development. The achievement of a leadership position also depends largely upon our ability to maximize the approval, acceptance and use of our product candidates and the availability of adequate financial resources to fund facilities, equipment, personnel, clinical testing, manufacturing and marketing. Another key aspect of remaining competitive in the industry is recruiting and retaining leading scientists and technicians to conduct our research activities and advance our development programs, including with the regulatory and commercial expertise to effectively advance and market our products.

Competition among products approved for sale may be based, among other things, on patent position, product efficacy, safety, patient convenience, delivery devices, reliability, availability, reimbursement and price. In addition, early entry of a new pharmaceutical product into the market may have important advantages in gaining product acceptance and market share. Accordingly, the relative speed with which we can develop products, complete the testing and approval process and supply commercial quantities of products will have a significant impact on our competitive position.

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 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.

Additional information about the competition that our marketed products face is set forth below and in Item 1A. Risk Factors included in this report.

GENERIC AND BIOSIMILARS COMPETITION

Certain of our products already face, or may face in the future, competition from the introduction of new originator therapies, generics, 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. Accordingly, the introduction of such products as well as other lower-priced competing products may significantly reduce both the price that we are able to charge for our products and the volume of products we sell, which will negatively impact our revenue. In some jurisdictions a decrease in reimbursed price is mandated by law. 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.

TECFIDERA

Multiple TECFIDERA generic entrants are now in North America, Brazil and certain European countries and have deeply discounted prices compared to TECFIDERA. The generic competition for TECFIDERA has significantly reduced our TECFIDERA revenue and we expect that TECFIDERA revenue will continue to decline. In November 2025 the Technical Boards of Appeal of the European Patent Office revoked our EP 2 653 873 patent related to TECFIDERA, after which we stopped enforcing this patent and its national counterparts.

RITUXAN

Biosimilar products referencing RITUXAN are available 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

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Genentech, as the sales of RITUXAN have decreased substantially compared to prior periods and we expect sales to continue to decrease.

TYSABRI

A biosimilar entrant of TYSABRI was approved in the U.S. and the E.U. in 2023. We expect that future sales of TYSABRI will continue to be adversely affected by the entrance of this biosimilar worldwide.

NEUROLOGY

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. Our MS products may be adversely affected if competitors continue to gain market share, or if other MS products that we or our competitors are developing are commercialized.

ALZHEIMER'S DISEASE

The market for the treatment of Alzheimer's disease is developing and could be subject to rapid change in the future. Most current treatments are symptomatic or intended to improve quality of life. We and our collaboration partner Eisai co-commercialize LEQEMBI, an anti-amyloid antibody for the treatment of Alzheimer's disease. Along with us, several companies are working to develop additional treatments. 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. in 2024 and in the E.U. in 2025. We are aware of other products now in development that, if approved, may also compete with LEQEMBI.

RARE DISEASE

SPINAL MUSCULAR ATROPHY

We face competition from an oral product EVRYSDI (risdiplam) and a gene therapy product ZOLGENSMA (onasemnogene abeparvovec-xioi). We expect that we will experience competition from both products in additional jurisdictions and new formulations of those products, which may adversely affect our sales of SPINRAZA.

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RESEARCH AND DEVELOPMENT PROGRAMS

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. By applying our expertise in biologics and our capabilities in small molecule, antisense and other technologies, we target specific medical needs where we believe new or better treatments are needed.

We intend to continue committing significant resources to targeted research and development opportunities where there is a significant unmet need and where a drug candidate has the potential to be highly differentiated. 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.

For additional information on our research and development expense included in our consolidated statements of income, please read Item 7. Management's Discussion and Analysis of Financial Condition and Results of Operations included in this report.

The table below highlights our current research and development programs that are in clinical trials and the current phase of such programs. Drug development involves a high degree of risk and investment, and the status, timing and scope of our development programs are subject to change. Important factors that could adversely affect our drug development efforts are discussed in Item 1A. Risk Factors included in this report.

(1) Collaboration program

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 and Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

BUSINESS RELATIONSHIPS

As part of our business strategy, we establish business relationships, including entering into licenses, joint ventures and collaborative arrangements with other companies, universities and medical research institutions, to assist in the clinical development and/or commercialization of certain of our products and product candidates and to provide support for our research programs. We also evaluate opportunities for acquiring products or rights to products and technologies that are complementary to our business from other companies, universities and medical research institutions.

Below is a brief description of certain business relationships and collaborations that expand our pipeline and provide us with certain rights to existing and potential new products and technologies. For additional information on certain

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of these relationships, including their ongoing financial and accounting impact on our business, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

EISAI

We have a collaboration agreement with Eisai to jointly develop and commercialize LEQEMBI (lecanemab), an anti-amyloid antibody for the treatment of Alzheimer's disease. Subject to the limitations in the LEQEMBI Collaboration Agreement, Eisai has final decision-making authority on all matters relating to the collaboration and serves as the lead of LEQEMBI development and regulatory submissions globally. We co-commercialize and co-promote LEQEMBI with Eisai. Our Collaboration Agreement provides that each commercialization plan shall allocate the responsibilities for the activities under the plan in an equitable fashion taking into account Biogen's and Eisai's respective capabilities and provides a meaningful role for each party. All costs, including research, development, sales and marketing expense, are shared equally between us and Eisai. We also share profits and losses equally. We currently have a supply agreement with Eisai to manufacture LEQEMBI drug substance and drug product through the end of 2031.

SUPERNUS (PREVIOUSLY SAGE)

We have a global collaboration and license agreement with Supernus 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.

GENENTECH

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.

UCB

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. All costs incurred for agreed indications, including research, development, sales and marketing expense, are shared equally between us and UCB. If marketing approval is obtained, both companies will jointly commercialize dapirolizumab pegol and share profits and losses equally.

IONIS

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 worldwide, exclusive, royalty-bearing licenses to develop and commercialize salanersen (BIIB115), an investigational ASO in development for SMA and BIIB080 (tau ASO) for the potential treatment of Alzheimer's disease.

DENALI

We have a collaboration and license agreement with Denali to co-develop and co-commercialize BIIB122, a small molecule inhibitor of LRRK2 for Parkinson's disease (LRRK2 Collaboration). Under the LRRK2 Collaboration, both companies share responsibility and costs for global development based on specified percentages as well as profits and losses for commercialization in the U.S. and China. Outside the U.S. and China we are responsible for commercialization and may pay Denali potential tiered royalties.

STOKE

We have a collaboration and license agreement with Stoke to co-develop and commercialize zorevunersen, an investigational ASO that targets the SCN1A gene for the potential treatment of Dravet syndrome, a rare form of genetic epilepsy associated with refractory seizures and neurodevelopmental impairments. Under this agreement, Stoke will continue to lead global development and retain exclusive development and commercialization rights for

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zorevunersen in the U.S., Canada and Mexico and we will have exclusive rights to commercialize zorevunersen in the rest of the world.

SAMSUNG BIOEPIS

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

REGULATORY

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

REGULATION OF PHARMACEUTICALS

PRODUCT APPROVAL AND POST-APPROVAL REGULATION IN THE U.S.

APPROVAL PROCESS

Before new pharmaceutical products may be sold in the U.S., preclinical studies and clinical trials of the products must be conducted and the results submitted to the FDA for approval. With limited exceptions, the FDA requires companies to register both pre-approval and post-approval clinical trials and disclose clinical trial results in public databases. Failure to register a trial or disclose study results within the required time periods could result in penalties, including civil monetary penalties. Clinical trial programs must establish efficacy, determine an appropriate dose and dosing regimen and define the conditions for safe use. This is a high-risk process that requires stepwise clinical studies in which the candidate product must successfully meet predetermined endpoints. The results of the preclinical and clinical testing of a product are then submitted to the FDA in the form of a BLA or NDA. In response to a BLA or NDA, the FDA may grant marketing approval, request additional information or deny the application if it determines the application does not provide an adequate basis for approval.

Product development and receipt of regulatory approval takes a number of years, involves the expenditure of substantial resources and depends on a number of factors, including the severity of the disease in question, the availability of suitable alternative treatments, potential safety signals observed in preclinical or clinical tests and the risks and benefits of the product as demonstrated in clinical trials. 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 unanticipated delays and/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 preclinical and/or clinical data.

The FDA has developed four distinct approaches intended to facilitate the development and expedite the regulatory review of therapeutically important drugs, especially when the drugs are the first available treatment or have advantages over existing treatments: accelerated approval, fast track, breakthrough therapy and priority review.

•Accelerated Approval: The FDA may grant “accelerated approval” to products that treat serious or life-threatening illnesses and that provide meaningful therapeutic benefits to patients over existing treatments. Under this pathway, the FDA may approve a product based on surrogate endpoints or clinical endpoints other than survival or irreversible morbidity. 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. 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. The FDA may withdraw approval if, for instance, post-marketing studies fail to verify clinical benefit, it becomes clear that

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restrictions on the distribution of the product are inadequate to ensure its safe use or if a sponsor fails to comply with the conditions of the accelerated approval.

•Fast Track: The FDA may grant "fast track" status to products that treat a serious condition and have data demonstrating the potential to address an unmet medical need or a drug that has been designated as a qualified infectious disease product.

•Breakthrough Therapy: The FDA may grant “breakthrough therapy” status to drugs designed to treat, alone or in combination with another drug or drugs, a serious or life-threatening disease or condition and for which preliminary clinical evidence suggests a substantial improvement over existing therapies based on a clinically significant endpoint. Breakthrough therapy status entitles the sponsor to earlier and more frequent meetings with the FDA regarding the development of nonclinical and clinical data and permits the FDA to offer product development or regulatory advice for the purpose of shortening the time to product approval. Breakthrough therapy status does not guarantee that a product will be eligible for priority review and does not ensure FDA approval.

•Priority Review: “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 PRV.

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

Regardless of the approval pathway employed, the FDA may require a sponsor to conduct additional post-marketing studies as a condition of approval to provide data on safety and effectiveness. If a sponsor fails to conduct the required studies, the FDA may withdraw its approval. In addition, 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 can mandate post-marketing restrictions to assure safe use. In such a case, the sponsor may be required to establish rigorous systems to assure use of the product under safe conditions. These systems are usually referred to as REMS. The FDA can impose financial penalties for failing to comply with certain post-marketing commitments, including REMS. In addition, any changes to an approved REMS must be reviewed and approved by the FDA prior to implementation.

ADVERSE EVENT REPORTING

We monitor information on side effects and adverse events reported during clinical studies and after marketing approval and report such information and events to regulatory agencies. Non-compliance with the FDA's safety reporting requirements may result in civil or criminal penalties. 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 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.

APPROVAL OF CHANGES TO AN APPROVED PRODUCT

If we seek to make certain types of changes to an approved product, such as adding a new indication, making certain manufacturing changes or changing manufacturers or suppliers of certain ingredients or components, the FDA will need to review and approve such changes in advance. In the case of a new indication, we are required to demonstrate with additional clinical data that the product is safe and effective for a use other than what was initially approved. 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.

REGULATION OF PRODUCT ADVERTISING AND PROMOTION

The FDA regulates all advertising and promotion activities and communications for products under its jurisdiction both before and after approval. Pursuant to FDA guidance, a company can make safety and efficacy claims either in or consistent with the product label. However, physicians may prescribe legally available drugs for uses that are not described in the drug's labeling. Such off-label prescribing is common across medical specialties, and often reflects a physician's belief that the off-label use is the best treatment for patients. The FDA does not regulate the behavior of physicians in their choice of treatments, but FDA regulations do impose stringent restrictions on manufacturers'

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communications regarding off-label uses. Failure to comply with applicable FDA requirements may subject a company to adverse publicity, enforcement action by the FDA, corrective advertising and the full range of civil and criminal penalties available to the government.

REGULATION OF COMBINATION PRODUCTS

Combination products are defined by the FDA to include products comprising two or more regulated components (e.g., a biologic and a device). Biologics and devices each have their own regulatory requirements, and combination products may have additional requirements. Some of our marketed products meet this definition and are regulated under this framework and similar regulations outside the U.S., and we expect that some of our pipeline product candidates may be evaluated for regulatory approval under this framework as well.

In May 2017 new regulations governing medical devices and in-vitro diagnostic medical devices entered into force in the E.U. The medical devices regulations became applicable in May 2021 and the in-vitro diagnostic medical devices regulations became applicable in May 2022. All products covered by these regulations will be required to comply with them at the end of the transitional periods. These regulations introduce new requirements, including for clinical investigation of certain classifications of medical devices, require increased regulatory scrutiny, enhance the requirements for post market surveillance and vigilance and provide for greater transparency. These regulations also change the requirements for assessment of the medical device components of integral drug-device combination products, necessitating assessment of the device components under both the medical device and medicinal product regulatory regimes.

On May 6, 2024, the FDA issued a Final Rule that explicitly states that in-vitro diagnostic products are medical devices under the Federal Food, Drug and Cosmetic Act, even when manufactured by clinical laboratories. This includes laboratory developed tests, which historically operated under FDA's enforcement discretion and were largely unregulated by the agency.

PRODUCT APPROVAL AND POST-APPROVAL REGULATION OUTSIDE THE U.S.

We market our products in numerous jurisdictions outside the U.S. Most of these jurisdictions have product approval and post-approval regulatory processes that are similar in principle to those in the U.S. In Europe, for example, where a substantial part of our ex-U.S. efforts are focused, there are several routes for marketing approval, depending on the type of product for which approval is sought. Under the centralized procedure, a company submits a single application to the EMA. 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. If the CHMP determines that the MAA fulfills the requirements for quality, safety and efficacy and that the medicine has a positive benefit risk balance, it will adopt a positive opinion recommending the granting of the marketing authorization by the EC. The CHMP opinion is not binding, but is typically adopted by the EC. An MAA approved by the EC is valid in all member states of the E.U. The centralized procedure is required for all biological products, orphan medicinal products and new treatments for neurodegenerative disorders, and it is available for certain other products, including those which constitute a significant therapeutic, scientific or technical innovation.

In addition to the centralized procedure, the European regulatory framework includes the following options for regulatory review and approval in the E.U. member states:

•a national procedure, where the first application is made to the competent authority in one E.U. member state only;

•a decentralized procedure, where applicants submit identical applications to several E.U. member states and receive simultaneous approval, if the medicine has not yet been authorized in any E.U. member state; and

•a mutual recognition procedure, where applicants that have a medicine authorized in one E.U. member state can apply for mutual recognition of this authorization in other E.U. member states.

As in the U.S., the E.U. also has distinct approaches intended to optimize the regulatory pathways for therapeutically important drugs, including the Priority Medicines Evaluation Scheme, accelerated assessment and conditional marketing authorization. Priority Medicines Evaluation Scheme is intended to provide additional support to medicine developers throughout the development process. Regulatory review timelines in the E.U. 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. Conditional marketing authorizations are valid for one year and can be renewed annually. The marketing authorization holder is required to complete specific obligations (ongoing or new studies and, in some cases, additional activities) with a view to providing

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comprehensive data confirming that the benefit risk balance is positive. Once comprehensive data on the product have been obtained, the marketing authorization may be converted into a standard marketing authorization.

Aside from the U.S. and the E.U., there are countries in other regions where it is possible to receive an "accelerated" review whereby the national regulatory authority will commit to truncated review timelines for products that meet specific medical needs.

In the E.U. there is detailed legislation on pharmacovigilance and extensive guidance on good pharmacovigilance practices. A failure to comply with the E.U. pharmacovigilance obligations may result in significant financial penalties for the marketing authorization holder.

Regardless of the approval process employed, various parties share responsibilities for the monitoring, detection and evaluation of adverse events post-approval, including national competent authorities, the EMA, the EC and the marketing authorization holder. The EMA’s Pharmacovigilance Risk Assessment Committee is responsible for assessing and monitoring the safety of human medicines and makes recommendations on product safety issues. Marketing authorization holders have an obligation to inform regulatory agencies of any new information which may influence the evaluation of benefits and risks of the medicinal product concerned.

In the U.S., the E.U. and other jurisdictions, regulatory agencies, including the FDA, conduct periodic inspections of NDA, BLA and marketing authorization holders to assess their compliance with pharmacovigilance obligations.

GOOD MANUFACTURING PRACTICES

Regulatory agencies regulate and inspect equipment, facilities and processes used in the manufacturing and testing of pharmaceutical and biologic products prior to approving a product. If, after receiving approval from regulatory agencies, a company makes a material change in manufacturing equipment, location or process, additional regulatory review and approval may be required. We also must adhere to current GMP and product-specific regulations enforced by regulatory agencies following product approval. The FDA, the EMA and other regulatory agencies also conduct periodic visits to re-inspect equipment, facilities and processes following the initial approval of a product. If, as a result of these inspections, it is determined that our equipment, facilities or processes do not comply with applicable regulations and conditions of product approval, regulatory agencies may seek civil, criminal or administrative sanctions or remedies against us, including significant financial penalties and the suspension of our manufacturing operations.

GOOD CLINICAL PRACTICES

The FDA, the EMA and other regulatory agencies promulgate regulations and standards for designing, conducting, monitoring, auditing and reporting the results of clinical trials to ensure that the data and results are accurate and that the rights and welfare of trial participants are adequately protected (commonly referred to as current GCP). Regulatory agencies enforce current GCP through periodic inspections of trial sponsors, principal investigators and trial sites, CROs and institutional review boards. If our studies fail to comply with applicable current GCP guidelines, the clinical data generated in our clinical trials may be deemed unreliable and relevant regulatory agencies may require us to perform additional clinical trials before approving our marketing applications. Noncompliance can also result in civil or criminal sanctions. We rely on third parties, including CROs, to carry out many of our clinical trial-related activities. Failure of such third parties to comply with current GCP can likewise result in rejection of our clinical trial data or other sanctions.

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. There are transitional provisions for clinical trials which are ongoing at the date of application. Clinical trial applications could be made under the Clinical Trial Directive (the existing regulatory framework) through January 2023. All clinical trials must fully comply with the Clinical Trial Regulation by January 2025. The regulation harmonizes the procedures for assessment and governance of clinical trials throughout the E.U. and will require that information on the authorization, conduct and results of each clinical trial conducted in the E.U. be publicly available.

APPROVAL OF BIOSIMILARS

In the U.S. 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 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

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biosimilar competition can be introduced. There is uncertainty, however, as the approval framework for biosimilars originally was enacted as part of the PPACA. There have been, and there are likely to continue to be, federal legislative and administrative efforts to repeal, substantially modify or invalidate some or all of the provisions of the PPACA. If the PPACA is repealed, substantially modified or invalidated, it is unclear what, if any, impact such action would have on biosimilar regulation.

A biosimilars approval pathway has been in place in the E.U. since 2003. The EMA has issued a number of scientific and product specific biosimilar guidelines, including requirements for approving biosimilars containing monoclonal antibodies. In the E.U., biosimilars are generally approved under the centralized procedure. The approval pathway allows sponsors of a biosimilar to seek and obtain regulatory approval based in part on reliance on the clinical trial data of an innovator product to which the biosimilar has been demonstrated, through comprehensive comparability studies, to be “similar.” In many cases, this allows biosimilars to be brought to market without conducting the full complement of clinical trials typically required for novel biologic drugs.

ORPHAN DRUG ACT

Under the U.S. 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. Orphan Drug Act has been enacted in other countries to encourage the research, development and marketing of medicines to treat, prevent or diagnose rare diseases. 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 ODD in the U.S., the E.U. and Japan; 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 PMN, IgAN and solid organ transplantation.

REGULATION PERTAINING TO PRICING AND REIMBURSEMENT

In both domestic and foreign markets, sales of our products depend, to a significant extent, on the availability and amount of reimbursement by third-party payors, including governments, private health plans and other organizations. Substantial uncertainty exists regarding the pricing and reimbursement of our products, and drug prices continue to receive significant scrutiny. Governments may regulate coverage, reimbursement and pricing of our products to control cost or affect utilization of our products. Challenges to our pricing strategies, by either government or private stakeholders, could harm our business. The U.S. and foreign governments have enacted and regularly consider additional reform measures that affect health care coverage and costs. Private health plans may also seek to manage cost and utilization by implementing coverage and reimbursement limitations. 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.

WITHIN THE U.S.

•Medicaid: Medicaid is a joint federal and state program that is administered by the states for low income and disabled beneficiaries. Under the Medicaid Drug Rebate Program, we are required to pay a rebate for each unit of product reimbursed by the state Medicaid programs. The amount of the rebate is established by law and is adjusted upward if the AMP increases more than inflation (measured by the Consumer Price Index - Urban). The rebate amount is calculated each quarter based on our report of current AMP and best price for each of our products to the CMS. The requirements for calculating AMP and best price are complex. We are required to report any revisions to AMP or best price previously reported within a certain period, which revisions could affect our rebate liability for prior quarters. 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.

•Medicare: Medicare is a federal program that is administered by the federal government. The program covers individuals age 65 and over as well as those with certain disabilities. Medicare Part B generally covers drugs that must be administered by physicians or other health care practitioners, are provided in connection with

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certain durable medical equipment or are certain oral anti-cancer drugs and certain oral immunosuppressive drugs. Medicare Part B pays for such drugs under a payment methodology based on the average sales price of the drugs. Manufacturers, including us, are required to provide average sales price information to the CMS on a quarterly basis. The manufacturer-submitted information is used to calculate Medicare payment rates. If a manufacturer is found to have made a misrepresentation in the reporting of average sales price, the governing statute provides for civil monetary penalties.

Medicare Part D provides coverage to enrolled Medicare patients for self-administered drugs (i.e., drugs that are not administered by a physician). Medicare Part D is administered by private prescription drug plans approved by the U.S. government. Each drug plan establishes its own Medicare Part D formulary for prescription drug coverage and pricing, which the drug plan may modify from time-to-time. The prescription drug plans negotiate pricing with manufacturers and pharmacies, and may condition formulary placement on the availability of manufacturer discounts. In addition, up until 2024, manufacturers, including us, were 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, 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 previous coverage gap provisions and establishes a $2,000 cap for out-of-pocket costs for Medicare beneficiaries beginning in 2025 (indexed to increase in future years), with manufacturers being responsible for up to 10.0% of costs up to the patient's out-of-pocket cap and up to 20.0% after that cap is reached.

The result of these changes for manufacturers, including us, may include: i) a material adverse effect on our revenue on drugs subject to “negotiation”; ii) new rebate liability for drugs subject to the inflation provisions, and iii) potential significant additional costs related to the Part D re-design.

•Federal Agency Discounted Pricing: Our products are subject to discounted pricing when purchased by federal agencies via the FSS. FSS participation is required for our products to be covered and reimbursed by the VA, Department of Defense, Coast Guard and PHS. Coverage under Medicaid, Medicare and the PHS pharmaceutical pricing program is also conditioned upon FSS participation. FSS pricing is intended not to exceed the price that we charge our most-favored non-federal customer for a product. In addition, prices for drugs purchased by the VA, Department of Defense (including drugs purchased by military personnel and dependents through the TriCare retail pharmacy program), Coast Guard and PHS are subject to a cap on pricing equal to 76.0% of the non-federal average manufacturer price (non-FAMP). An additional discount applies if non-FAMP increases more than inflation (measured by the Consumer Price Index - Urban). In addition, if we fail to provide information timely or we are found to have knowingly submitted false information to the government, the governing statute provides for civil monetary penalties.

•340B Discounted Pricing: 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 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. In addition, we may, but are not required to, offer these covered entities a price lower than the 340B ceiling price. The 340B discount formula is based on AMP and is generally similar to the level of rebates calculated under the Medicaid Drug Rebate Program.

OUTSIDE THE U.S.

Outside the U.S., our products are paid for by a variety of payors, with governments being the primary source of payment. Governments may determine or influence reimbursement of products and may also set prices or otherwise regulate pricing. Negotiating prices with governmental authorities can delay commercialization of our products. 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.

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REGULATION PERTAINING TO SALES AND MARKETING

We are subject to various federal and state laws pertaining to health care “fraud and abuse,” including anti-kickback laws and false claims laws. Anti-kickback laws generally prohibit a prescription drug manufacturer from soliciting, offering, receiving or paying any remuneration to generate business, including the purchase or prescription of a particular drug. Although the specific provisions of these laws vary, their scope is generally broad and there may be no regulations, guidance or court decisions that clarify how the laws apply to particular industry practices. There is therefore a possibility that our practices might be challenged under anti-kickback or similar laws. False claims laws prohibit anyone from knowingly and willingly presenting, or causing to be presented, for payment to third-party payors (including Medicare and Medicaid), claims for reimbursed drugs or services that are false or fraudulent, claims for items or services not provided as claimed or claims for medically unnecessary items or services. Our activities relating to the sale and marketing of our products may be subject to scrutiny under these laws. Violations of fraud and abuse laws may be punishable by criminal or civil sanctions, including fines and civil monetary penalties, and exclusion from federal health care programs (including Medicare and Medicaid). In the U.S., federal and state authorities are paying increased attention to enforcement of these laws within the pharmaceutical industry and private individuals have been active in alleging violations of the laws and bringing suits on behalf of the government under the federal civil False Claims Act. If we were subject to allegations concerning, or were convicted of violating, these laws, our business could be harmed.

Laws and regulations have been enacted by the federal government and various states to regulate the sales and marketing practices of pharmaceutical manufacturers. The laws and regulations generally limit financial interactions between manufacturers and health care providers or require disclosure to the government and public of such interactions. The laws include federal and state “sunshine” transparency reporting provisions. The sunshine provisions apply to pharmaceutical manufacturers with products reimbursed under certain government programs and require those manufacturers to disclose annually to the federal government (for re-disclosure to the public) certain payments made to physicians and certain other healthcare practitioners or to teaching hospitals. State laws may also require disclosure of pharmaceutical pricing information and marketing expenditures. Many of these laws and regulations contain ambiguous requirements. Given the lack of clarity in laws and their implementation, our reporting actions could be subject to the penalty provisions of the pertinent federal and state laws and regulations. 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 LAWS AND REGULATIONS

FOREIGN ANTI-CORRUPTION

We are subject to various federal and foreign laws that govern our international business practices with respect to payments to government officials. Those laws include the U.S. FCPA, which prohibits U.S. companies and their representatives from paying, offering to pay, promising to pay or authorizing the payment of anything of value to any foreign government official, government staff member, political party or political candidate for the purpose of obtaining or retaining business or to otherwise obtain favorable treatment or influence a person working in an official capacity. 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 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. Bribery Act 2010 (Bribery Act), which proscribes giving and receiving bribes in the public and private sectors, bribing a foreign public official and failing to have adequate procedures to prevent employees and other agents from giving bribes. U.S. companies that conduct business in the U.K. generally will be subject to the Bribery Act. Penalties under the Bribery Act include significant fines for companies and criminal sanctions for corporate officers under certain circumstances.

NIH GUIDELINES

We seek to conduct research at our U.S. facilities in compliance with the current U.S. National Institutes of Health Guidelines for Research Involving Recombinant DNA Molecules (NIH Guidelines). By local ordinance, we are required to, among other things, comply with the NIH Guidelines in relation to our facilities in RTP and are required to operate pursuant to certain permits.

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OTHER LAWS

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

Data Privacy

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. Data Protection Directive and related country-specific legislation. The GDPR took effect in May 2018 and governs the collection and use of personal data in the E.U. The GDPR, which is wide-ranging in scope, imposes several requirements relating to the consent of the individuals to whom the personal data relates, the information provided to the individuals, the security and confidentiality of the personal data, data breach notification and the use of third-party processors in connection with the processing of the personal data. The GDPR also imposes strict rules on the transfer of personal data out of the E.U. to the U.S., provides an enforcement authority and imposes large penalties for noncompliance, including the potential for fines of up to €20.0 million or 4.0% of the annual global revenue of the infringer, whichever is greater. In addition, several U.S. state 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 regularly review our manufacturing capacity, capabilities, processes and facilities. In order to support our future growth and drug development pipeline, we expanded our large molecule production capacity and built a large-scale biologics manufacturing facility in Solothurn, Switzerland. The Solothurn facility is operational and has been approved for the manufacture of LEQEMBI and TYSABRI. We believe that the Solothurn facility will support our anticipated near to mid-term needs for the manufacturing of biologic assets. The plant represents a significant increase in our overall manufacturing capacity. Additionally, we continue to invest to modernize, automate and support the capacity requirements for our pipeline and existing products at our existing manufacturing facilities in RTP, North Carolina.

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.

MANUFACTURING FACILITIES

Our manufacturing facilities include:

* Other includes products manufactured for contract manufacturing partners.

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

The parenteral facility adds capabilities and capacity for filling biologics into vials and is used for filling product candidates. The oral solid dose products facility can supplement our outsourced small molecule manufacturing capabilities.

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We have an oligonucleotide synthesis manufacturing facility in RTP. This facility gives us the capability to manufacture both commercial and clinical ASOs, including QALSODY, and beginning in 2026 this facility will manufacture SPINRAZA.

Additionally, in 2025 we acquired a sterile fill finish manufacturing facility in Athlone, Ireland. This facility will provide us with the capability for syringe and cartridge sterile fill finish across our current manufacturing network, incorporating our MS product portfolio and our late-stage portfolio including litifilimab and felzartamab.

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, VUMERITY, SKYCLARYS and ZURZUVAE, 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. We endeavor to assure continuity of supply of such raw materials, devices and supplies 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 group.

CORPORATE RESPONSIBILITY

INTRODUCTION

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.

GOVERNANCE

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 link a portion of our employees' and executive officers' compensation to advancing our Corporate Responsibility goals.

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.

RISK MANAGEMENT

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.

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

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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. Physical risk considers how the physical impacts of climate change (e.g., increased frequency and intensity of storms, drought, fires, floods) can directly damage physical assets or otherwise impact their value or productivity. Transition risk considers how changes in policy, regulations, culture, technology, business practices and market preferences to address climate change (e.g., carbon pricing policies, power generation shifts from fossil fuels to renewable energy) can lead to changes in the value of assets and businesses. 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 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.

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

HUMAN CAPITAL

As of December 31, 2025, we had approximately 7,500 employees worldwide. Approximately 4,200 employees were employed in the U.S. and approximately 3,300 employees were employed in foreign countries. As of December 31, 2025, 29.8% of Biogen’s U.S. manager-level and above positions were held by ethnic or racial minorities. Globally, 50.0% of Biogen’s positions at the director-level and above were held by women as of December 31, 2025.

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. Our culture is underpinned by the New Biogen Way, aimed at maintaining our spirit of innovation and patient-centricity while advancing an entrepreneurial business mindset and results-focused approach.

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

We utilize an annual survey to provide employees with an opportunity to provide feedback and to measure employee engagement. 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 in taking 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. 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 working remotely, virtual learning plays a key role. We utilize online resources such as Biogen University, Coursera and Franklin Covey.

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 our ongoing success. 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 fairly within a reasonable range, taking into consideration factors such as role; market data; job location; relevant experience; and individual, business unit and company performance. 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.

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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. 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 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; and

•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 caregivers of individuals with disabilities and their allies.

•Biogen Veterans Network: Encourages veterans and allies to connect and support one another.

•IGNITE: Brings together early-career professionals and their allies.

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

•ourIMPACT: 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.

•ReachOUT: Brings together LGBTQ+ employees and their allies.

•Women’s Impact Network: Creates networking, mentoring and learning opportunities for women and allies worldwide.

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INFORMATION ABOUT OUR EXECUTIVE OFFICERS (as of February 6, 2026)

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AVAILABLE INFORMATION

Our principal executive offices are located at 225 Binney Street, Cambridge, MA 02142 and our telephone number is (617) 679-2000. Our website address is www.biogen.com. We make available free of charge through the Investors section of our website our Annual Reports on Form 10-K, Quarterly Reports on Form 10-Q, Current Reports on Form 8-K and all amendments to those reports as soon as reasonably practicable after such material is electronically filed with or furnished to the SEC. We include our website address in this report only as an inactive textual reference and do not intend it to be an active link to our website. The contents of our website are not incorporated into this report.

USE OF WEBSITE TO PROVIDE INFORMATION

From time to time, we have used, or expect in the future to use, our investor relations website (investors.biogen.com), the Biogen LinkedIn account (linkedin.com/company/biogen/-) and the Biogen X account (https://x.com/biogen) as a means of disclosing information to the public in a broad, non-exclusionary manner, including for purposes of the SEC’s Regulation Fair Disclosure (Reg FD). Accordingly, investors should monitor our investor relations website and these social media channels in addition to our press releases, SEC filings, public conference calls and websites, as the information posted on them could be material to investors.