Biogen Inc. shares climbed 15.1% over the course of 2025, outperforming broader biotech benchmarks and reflecting renewed investor confidence. This gain follows the company’s successful commercial execution and positive clinical readouts, marking one of the strongest annual returns among large-cap biotechnology firms. Trading volumes accelerated in key sessions, underscoring growing retail and institutional demand for the stock.

Biogen’s recently launched Alzheimer’s treatment Leqembi has exceeded early adoption forecasts, contributing significantly to U.S. specialty channel sales in its first full year on the market. Meanwhile, Skyclarys, an Nrf2 activator for Friedreich’s ataxia, recorded third-quarter revenues of $132.9 million, a 29.9% year-over-year increase. This performance underscores Biogen’s ability to commercialize novel therapies and diversify its revenue base beyond its legacy multiple sclerosis franchise.

Looking ahead, analysts expect Biogen’s earnings before interest and taxes (EBIT) to expand as Leqembi uptake intensifies and Skyclarys gains reimbursement coverage across major European markets. The company is also advancing a pipeline of next-generation neurodegenerative candidates, including an anti-tau antibody in mid-stage studies. With R&D spending projected to rise by approximately 10% year-over-year, Biogen aims to sustain a balanced portfolio of marketed products and late-stage assets, positioning itself competitively against peers developing similar neurology treatments.