Biogen Inc. (Nasdaq: BIIB; LSE: 0R1B) discovers, develops, manufactures and commercializes therapies primarily for neurological and neurodegenerative diseases, including multiple sclerosis, spinal muscular atrophy, Alzheimer's disease, Friedreich's ataxia and postpartum depression; its core products include TYSABRI (natalizumab), VUMERITY (diroximel fumarate) and TECFIDERA (dimethyl fumarate) for multiple sclerosis, SPINRAZA (nusinersen) for spinal muscular atrophy, LEQEMBI (lecanemab, partnered with Eisai) for Alzheimer's disease, SKYCLARYS (omaveloxolone) for Friedreich's ataxia, ZURZUVAE (zuranolone) for postpartum depression, PLEGRIDY (peginterferon beta-1a) and AVONEX (interferon beta-1a) for multiple sclerosis, as well as developmental candidates in immunology and rare diseases such as felzartamab and salanersen. The company operates globally with primary markets in the United States, Europe, Asia and other regions, maintaining manufacturing facilities in North Carolina and research hubs in Cambridge, Massachusetts, and South San Francisco, California. Founded in 1978 and headquartered at 225 Binney Street in Cambridge, Massachusetts, Biogen employs approximately 7,600 people and generated $9.7 billion in revenue in 2024. Recent developments include the November 2025 completion of its acquisition of Alcyone Therapeutics to advance the ThecaFlex DRx drug delivery system for neurological disorders, a $50 million upfront collaboration with Dayra Therapeutics announced in November 2025 to develop oral macrocyclic peptides for high-priority immunological targets with options for further acquisition and milestones, geographic expansions for SKYCLARYS with approvals in the United Kingdom and Brazil, strong growth in new launches such as LEQEMBI (up 395% year-over-year in Q1 2025), ZURZUVAE and SKYCLARYS driving overall revenue increases amid diversification beyond multiple sclerosis, pipeline progress with positive Phase 1b data for salanersen in spinal muscular atrophy and new lupus data for dapirolizumab pegol, and plans for a new global headquarters in Cambridge opening in 2028.