Biogen is a global biopharmaceutical company that discovers, develops and sells innovative therapies for serious and complex diseases, with a strong focus on neurology, immunology and rare diseases. The company generates revenue primarily from marketed therapeutics, including a broad multiple sclerosis portfolio, the first approved treatments for spinal muscular atrophy and a genetic form of amyotrophic lateral sclerosis, and disease-modifying therapies for Alzheimer's disease developed with partners. Biogen also earns revenue from collaboration agreements—including a 50% share of Alzheimer's treatment revenue—and from biosimilar medicines, while continuing to expand its pipeline through internal research and development, external partnerships and acquisitions.