BIOGEN INC

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. and the E.U. 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 TECFIDERA, VUMERITY, AVONEX, PLEGRIDY and TYSABRI for the treatment of MS; SPINRAZA for the treatment of SMA; SKYCLARYS for the treatment of FA; QALSODY for the treatment of ALS; and FUMADERM for the treatment of severe plaque psoriasis.

We also have collaborations with Eisai on the commercialization of LEQEMBI for the treatment of Alzheimer's disease and Sage on the commercialization of ZURZUVAE for the treatment of PPD. 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 and follicular lymphoma; 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; FLIXABI, an infliximab biosimilar referencing REMICADE; and BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, in certain international markets, as well as TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, in the U.S. and certain international markets. We also have commercialization rights related to OPUVIZ, an aflibercept biosimilar referencing EYLEA.

On July 2, 2024, we completed the acquisition of HI-Bio. As a result of this transaction we acquired HI-Bio's lead asset, felzartamab, an anti-CD38 antibody currently being evaluated for three leading indications, AMR, PMN and IgAN. For additional information on our acquisition of HI-Bio, please read Note 2, Acquisitions, to our consolidated financial statements included in this report.

KEY BUSINESS DEVELOPMENTS

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

ACQUISITIONS AND DIVESTITURES

HUMAN IMMUNOLOGY BIOSCIENCES

On July 2, 2024, we completed the acquisition of all of the issued and outstanding shares of HI-Bio, a privately-held clinical-stage biotechnology company focused on targeted therapies for patients with severe immune-mediated diseases. HI-Bio's lead asset, felzartamab, an anti-CD38 antibody, is currently being evaluated for three leading indications, AMR, PMN and IgAN. Felzartamab has received Breakthrough Therapy Designation and ODD from the FDA for development in the treatment of PMN and AMR. Subsequent to our acquisition, felzartamab received ODD in the E.U. in IgAN and solid organ transplantation. The acquisition of HI-Bio is expected to augment our pipeline and build on our expertise in immunology.

Under the terms of this acquisition, we paid shareholders of HI-Bio approximately $1.15 billion at closing and may pay up to an additional$650.0 million in potential future development and regulatory milestone payments. We funded this acquisition through available cash on hand and accounted for this acquisition as a business combination using the acquisition method of accounting in accordance with ASC Topic 805, Business Combinations, and recorded assets acquired and liabilities assumed at their respective fair values as of the acquisition date. For additional information on our acquisition of HI-Bio, please read Note 2, Acquisitions, to our consolidated financial statements included in this report.

SALE OF PRIORITY REVIEW VOUCHER

In April 2024 we completed the sale of our rare pediatric disease PRV, generated by the development associated with SPINRAZA, to a third party. In consideration for the PRV we received a cash payment of $103.0 million upon the closing of the PRV purchase, of which approximately $14.4 million was paid to Ionis. Our net portion of approximately $88.6 million was recognized in gain on sale of priority review voucher, net within our consolidated statements of income for the year ended December 31, 2024. For additional information on the sale of our PRV, please read Note 3, Dispositions, to our consolidated financial statements included in this report.

DEVELOPMENTS IN KEY COLLABORATIVE RELATIONSHIPS

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

United States

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

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

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

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

Rest of World

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

•In January 2025 we and Eisai announced an update regarding the ongoing regulatory review of the MAA for lecanemab in the E.U., which the CHMP of the EMA previously adopted a positive opinion on in November 2024. The EC has asked the CHMP to consider information on the safety of lecanemab that became available after the adoption of the CHMP opinion in November 2024 and whether this may require an update of the opinion, and to consider whether the wording of the risk minimization measures in the opinion is clear enough to ensure correct implementation. These will be discussed at the CHMP meeting in February 2025.

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

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

•In October 2024 the Therapeutic Goods Administration of Australia issued a public statement about the initial decision not to register lecanemab. In December 2024 Eisai submitted a request for reconsideration of this decision.

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

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

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

UCB COLLABORATION

In September 2024 we and UCB announced positive topline data from the Phase 3 PHOENYCS GO study of dapirolizumab pegol, a novel Fc-free anti-CD40L drug candidate, in people living with moderate-to-severe SLE. The Phase 3 study met the primary endpoint demonstrating clinical improvement in moderate-to-severe SLE with clinical improvements observed among key secondary endpoints. Based on these results, UCB and Biogen initiated a second Phase 3 study in late 2024.

MANAGEMENT CHANGES

•In October 2024 we announced that Michael R. McDonnell, Executive Vice President and Chief Financial Officer, plans to retire from Biogen on March 1, 2025. Upon Mr. McDonnell's retirement, Robin C. Kramer, currently Senior Vice President and Chief Accounting Officer at Biogen, will assume the role of Executive Vice President and Chief Financial Officer.

•In January 2025 we announced the appointment of Sean Godbout as Vice President, Chief Accounting Officer and Global Corporate Controller, effective March 1, 2025, upon the transition of Robin C. Kramer, currently Senior Vice President and Chief Accounting Officer at Biogen, to the role of Executive Vice President and Chief Financial Officer.

BOARD OF DIRECTORS UPDATE

•Effective October 1, 2024, Lloyd B. Minor, M.D. joined our Board of Directors.

•Effective January 1, 2025, Sir Menelas (Mene) Pangalos, Ph.D. joined our Board of Directors.

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

PRODUCT AND PIPELINE DEVELOPMENTS

•In October 2024 Eisai presented data on benefits of long-term administration of dual-acting LEQEMBI at the 2024 CTAD conference. The data presented additional measures resulting from the three years of continuous LEQEMBI treatment, showing that 46% of patients improved or had no decline and 33% showed improvement from baseline on the CDR-SB. On the ADAS-Cog14 measurement scale, 46% of patients showed improvement or no decline and 43% showed improvement. On the ADCS MCI-ADL measurement scale, 51% of patients showed improvement or no decline and 48% showed improvement.

•In July 2024 Eisai announced the results of a detailed analysis of the Phase 3 CLARITY Alzheimer's disease study of LEQEMBI at the 2024 AAIC conference. The study provided further Phase 3 analysis showing three years of continuous LEQEMBI treatment reduced clinical decline by -0.95 on CDR-SB showing continued clinically and personally meaningful benefit for early Alzheimer's disease patients.

IMMUNOLOGY

felzartamab

•Felzartamab was granted ODD in the E.U. in IgAN and solid organ transplantation in November 2024 and December 2024, respectively.

•In October 2024 we presented complete results from the Phase 2 IGNAZ study evaluating felzartamab, an investigational anti-CD38 monoclonal antibody, in people living with IgAN during the American Society of Nephrology Kidney Week 2024. The results from the study showed substantial reductions in proteinuria, stabilization of kidney function and sustained treatment effect more than 18 months after the last dose of felzartamab.

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

SPINRAZA (nusinersen)

•In January 2025 the FDA accepted the supplemental NDA and the EMA validated the application for a higher dose regimen of nusinersen for SMA. The higher dose regimen of nusinersen comprises a more rapid loading regimen, two 50 mg-doses 14 days apart, and higher maintenance regimen, 28 mg, every four months, compared to the currently approved dose of SPINRAZA.

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

•In March 2024 we announced new data from the Phase 4 RESPOND study for SPINRAZA. The study showed that neurofilament levels, an indicator of neurodegeneration, were reduced in nearly all study participants treated with SPINRAZA. The reductions in biomarker complement previously reported RESPOND study efficacy results showing improved motor function in most participants treated with SPINRAZA after gene therapy.

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

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

QALSODY

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

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

•In May 2024 the EC approved QALSODY in the E.U. for the treatment of adults with ALS associated with a mutation in the SOD1 gene. QALSODY is the first treatment approved in the E.U. to target a genetic cause of ALS.

DISCONTINUED PROGRAMS AND STUDIES

SAGE COLLABORATION

zuranolone

In October 2024 we and Sage agreed to not pursue further development of zuranolone for the potential treatment of MDD. This decision was based on the significant new investment and time we expect would be needed to conduct the additional studies required to support approval of this indication.

BIIB124

In July 2024 we and Sage announced that the Phase 2 KINETIC 2 dose-range study of BIIB124 did not meet its endpoints. Based on these results, we discontinued our further development of BIIB124 and terminated our rights under the collaboration and license agreement specific to BIIB124, effective February 17, 2025.

SAMSUNG BIOEPIS 2019 DEVELOPMENT AND COMMERCIALIZATION AGREEMENT

In October 2024 we notified Samsung Bioepis of our decision to terminate our 2019 Development and Commercialization Agreement (the DCA Agreement) solely within the U.S. and Canada. Biogen will transfer commercialization rights for BYOOVIZ and OPUVIZ in the U.S. and Canada back to Samsung Bioepis over a period of up to 18 months. During this transition period, we will continue to commercialize BYOOVIZ. The termination does not impact the other markets in the DCA Agreement.

IONIS COLLABORATION

BIIB105

In May 2024 we and Ionis announced that the Phase 1/2 ALSpire study of BIIB105, an investigational ASO for the potential treatment of ALS, did not meet its endpoints. Based on these results, we discontinued our further development of BIIB105.

BIIB121

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

MERZ THERAPEUTICS (PREVIOUSLY ACORDA THERAPEUTICS, INC.)

In January 2024 we notified Acorda of our decision to terminate our collaboration and license agreement, effective January 1, 2025, whereby Acorda regained global commercialization rights to FAMPYRA. On April 1, 2024, Acorda filed for bankruptcy protection and announced its intention to sell substantially all of Acorda's assets to a third party. On July 10, 2024, Merz Therapeutics announced that its subsidiary Merz Pharmaceuticals LLC had completed the acquisition of FAMPYRA, and related assets from Acorda. We are now working with Merz Therapeutics on the transition of global commercialization rights of FAMPYRA and we expect to recognize minimal revenue in 2025.

BIIB143 (cemdomespib)

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

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, 2024, 2023 and 2022.

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

(2) Rare disease includes SPINRAZA, QALSODY, which became commercially available in the U.S. during the second quarter of 2023 and commercially available in the E.U. during the second quarter of 2024, and SKYCLARYS, which was obtained as part of our acquisition of Reata in September 2023. SKYCLARYS became commercially available in the U.S. during the second quarter of 2023 and we began recognizing revenue from SKYCLARYS in the U.S. during the fourth quarter of 2023, subsequent to our acquisition. SKYCLARYS was approved and became commercially available in the E.U. during the first quarter of 2024.

(3) Biosimilars includes BENEPALI, IMRALDI, FLIXABI, BYOOVIZ, which became commercially available in certain international markets in 2023, and TOFIDENCE, which became commercially available in the U.S. during the second quarter of 2024.

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

(5) Anti-CD20 therapeutic programs include RITUXAN, RITUXAN HYCELA, GAZYVA, OCREVUS and LUNSUMIO, which became commercially available in the U.S. during the first quarter of 2023.

(6) Other includes FUMADERM, ADUHELM and ZURZUVAE, which became commercially available in the U.S. during the fourth quarter of 2023.

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

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:

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

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.

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, which became commercially available in the U.S. during the fourth quarter of 2023. 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 Sage, please read Note 19, Collaborative and Other Relationships, to our consolidated financial statements included in this report.

Rare disease includes SPINRAZA for SMA, QALSODY for ALS, which became commercially available in the U.S. during the second quarter of 2023 and commercially available in the E.U. during the second quarter of 2024, and SKYCLARYS for FA, which was obtained as part of our acquisition of Reata in September 2023. SKYCLARYS became commercially available in the U.S. during the second quarter of 2023 and we began recognizing revenue from SKYCLARYS in the U.S. during the fourth quarter of 2023, subsequent to our acquisition. SKYCLARYS was approved and became commercially available in the E.U. during the first quarter of 2024.

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

Our Rare disease products and major markets are as follows:

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; FLIXABI, an infliximab biosimilar referencing REMICADE; and BYOOVIZ, a ranibizumab biosimilar referencing LUCENTIS, in certain international markets, as well as TOFIDENCE, a tocilizumab biosimilar referencing ACTEMRA, which became commercially available in the U.S. during the second quarter of 2024 and approved in the E.U. during the second quarter of 2024. We also have commercialization rights related to OPUVIZ, an aflibercept biosimilar referencing EYLEA, which was approved in the E.U. during the fourth quarter of 2024.

Our current biosimilar products and major markets are as follows:

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.

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.

OTHER

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

We are dedicated to helping patients obtain access to our therapies. Our patient support representatives have access to a suite of financial assistance tools. With those tools, we help patients understand their insurance coverage and, if needed, help patients compare insurance options and programs. In the U.S., we have established programs that provide co-pay assistance or free product for qualified uninsured or underinsured patients, based on specific eligibility criteria.

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

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

DISTRIBUTION ARRANGEMENTS

We distribute our products in the U.S. principally through wholesale and specialty distributors of pharmaceutical products and specialty pharmacies, mail order specialty distributors or shipping service providers. 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. We also distribute BYOOVIZ in certain international markets and TOFIDENCE in the U.S.

Our product sales to two wholesale distributors each accounted for more than 10.0% of our total revenue for the years ended December 31, 2024, 2023 and 2022, and on a combined basis, accounted for approximately 39.3%, 36.9% and 37.9%, respectively, of our gross product revenue. 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. and Japan and in selected other countries for inventions originating from our research and development efforts and those we license or acquire. In addition, we license rights to various patents and patent applications.

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 marketing authorization, for a set period of time, the exclusive use of the proprietary pre-clinical 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.

Footnotes follow on next page.

(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.

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.

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 generic versions, prodrugs and biosimilars of existing products and products approved under abbreviated regulatory pathways. Such products are likely to be sold at substantially lower prices than branded products. 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.

Multiple TECFIDERA generic entrants are now in North America, Brazil and certain European countries and have deeply discounted prices compared to TECFIDERA. We are defending the validity of our EP 2 653 873 patent related to TECFIDERA and expiring in 2028 in opposition proceedings in the European Patent Office. We are also engaged in litigation in Europe to defend and enforce national counterparts of our EP 2 653 873 patent, with mixed results. The generic competition for TECFIDERA has significantly reduced our TECFIDERA revenue and we expect that TECFIDERA revenue will continue to decline.

Biosimilar products referencing RITUXAN have launched in the U.S and are being offered at lower prices. This competition has had a significant adverse impact on the pre-tax profits of our collaboration arrangements with Genentech, as the sales of RITUXAN have decreased substantially compared to prior periods. We expect that biosimilar competition will continue to increase as these products capture additional market share and that this will have a significant adverse impact on our co-promotion profits in the U.S. in future years.

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

MULTIPLE SCLEROSIS

Competition in the MS market is intense. Along with us, a number of companies are working to develop additional treatments for MS that may in the future compete with our MS products. One competing product that was approved in the U.S. in 2017 and in the E.U. in 2018 is OCREVUS, a treatment for RMS and PPMS that was developed by Genentech. Another competing product that was approved in the U.S. in 2020 and the E.U. in 2021 is KESIMPTA, a treatment for RMS that was developed by Novartis AG. While we have a financial interest in OCREVUS, future sales of our MS products may be adversely affected if OCREVUS and KESIMPTA continue to gain market share, or if other MS products that we or our competitors are developing are commercialized.

The market for the treatment of Alzheimer's disease is undeveloped and could be subject to rapid change in the future. Most current treatments are symptomatic or intended to improve quality of life. Along with us, several companies are working to develop additional treatments. We and our collaboration partner Eisai co-commercialize LEQEMBI, an anti-amyloid antibody for the treatment of Alzheimer's disease. In 2024 a competing product, KISUNLA, a treatment for early symptomatic Alzheimer's disease that was developed by Eli Lilly and Company, was approved in the U.S. We are aware of other products now in development that, if approved, may also compete with LEQEMBI.

SPINAL MUSCULAR ATROPHY

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

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, gene therapy 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

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

(3) Granted approval in the U.S. in August 2023, pending DEA scheduling, which was completed in October 2023, under the brand name ZURZUVAE.

(4) Granted approval in the U.S. in February 2023 and the E.U. in February 2024, under the brand name SKYCLARYS.

(5) Granted accelerated approval in the U.S. in April 2023, the E.U. in May 2024 and China in October 2024 under the brand name QALSODY.