Biogen to Pay $5.6 Billion for Apellis at 140% Premium, Gains $689 Million in 2025 Drugs
Biogen will pay $5.6bn at $41 per share—a 140% premium to 30 March’s close—to acquire Apellis and its GA therapy Syfovre plus kidney drug Empaveli, which generated $689m in 2025. It forecasts mid-to-high-teens sales growth through 2028, anticipates closing in Q2 2026 and projects $1.54bn additional revenue by 2030.
1. Deal Terms
Biogen will acquire Apellis for $5.6bn in cash, paying $41 per share. This represents a near 140% premium to Apellis’s closing price on 30 March.
2. Pipeline Expansion
The acquisition adds Syfovre (pegcetacoplan) for geographic atrophy and Empaveli for kidney disease, which together generated $689m in 2025. Biogen expects mid-to-high-teens annual sales growth for these therapies through 2028 and bolsters expertise for its kidney candidate felzartamab.
3. Financial Implications
Analysts project the deal could add $1.54bn to Biogen’s top line by 2030 and offset anticipated declines in its multiple sclerosis franchise. Consensus estimates foresee Syfovre reaching $1bn and Empaveli $747m by 2031.
4. Closing Timeline and Investor Reaction
Biogen anticipates closing the transaction in Q2 2026. The announcement led to a more than 4% drop in Biogen shares at the next market opening.