Alzheimer's and Rare Disease New Drugs Drive Growth Amid Traditional MS Slowdown

Biogen Inc. (NASDAQ: BIIB) reported fourth-quarter 2025 revenues of approximately $2.3 billion (roughly ₩3 trillion) and full-year sales near $9.9 billion (about ₩13 trillion). Growth-brand revenues—driven by LEQEMBI, SKYCLARYS and ZURZUVAE—rose 6 percent year-over-year, largely offsetting declines in its multiple sclerosis portfolio. The company highlighted key pipeline milestones, including the U.S. FDA’s priority review of LEQEMBI’s subcutaneous formulation, IQLIK, and Breakthrough Therapy designation for its autoimmune candidate, litifirimab. Biogen also projected 2026 non-GAAP diluted EPS in the mid-$15 range while forecasting overall revenue to decline by the mid-single digits.

On the same day, Biogen’s shares held in a tight range amid investor focus on its fourth-quarter beat on consensus estimates and an earnings outlook that surpassed expectations. Attention was also drawn to the fact that combined annual revenues from its growth products are approaching $1 billion (around ₩1 trillion). Earlier approvals in the U.S., Europe and select Middle Eastern markets for both the intravenous and at-home administration forms of LEQEMBI have further stoked hopes for medium- to long-term market expansion.

Headquartered in Massachusetts, Biogen is a major biotech company that has established its neurology franchise through multiple sclerosis therapies and SPINRAZA for spinal muscular atrophy. More recently, in partnership with Japan’s Eisai, Biogen has launched the Alzheimer’s treatment LEQEMBI and a suite of rare neuro-immune disease candidates to reduce reliance on its traditional MS franchise and diversify its growth drivers.