Biogen shares rise 5.37% intraday after Q4 earnings beat driven by Alzheimer's drug sales and growth products.

Biogen surged 5.37% intraday following the release of its Q4 2025 results, driven by better-than-expected earnings and revenue. The company reported adjusted EPS of $1.99, exceeding estimates by 22.1%, and revenue of $2.28 billion, up 3.6% above forecasts. Strong performance in Alzheimer’s drug Leqembi (collaboration revenue $47 million, in-market sales $134 million) and growth in Skyclarys and Zurzuvae offset declines in multiple sclerosis products. Management highlighted resilience in the MS franchise and projected 2026 EPS guidance above consensus. The stock’s intraday rally aligned with the earnings beat and positive guidance, despite longer-term concerns over biosimilars impacting Tysabri sales.