Biogen to acquire Apellis
Biogen has announced a definitive agreement to acquire Apellis Pharmaceuticals for approximately $5.6 billion, adding two marketed complement inhibitors, including pegcetacoplan (SYFOVRE®), to its portfolio.
SYFOVRE® (pegcetacoplan) is approved in the United States and Australia for the treatment of geographic atrophy (GA) secondary to age-related macular degeneration. The C3 inhibitor was evaluated in the Phase 3 OAKS and DERBY trials, where it reduced the rate of GA lesion growth compared with sham treatment, with increasing effects over time.
However, the drug has not been approved in Europe. The European Medicines Agency (EMA) refused marketing authorization for pegcetacoplan for GA, confirming its decision in September 2024. Regulators concluded that the observed slowing of lesion growth did not translate into a clinically meaningful benefit in visual function.
Long-term data from the open-label GALE extension study, presented in 2025, suggested that treatment with pegcetacoplan may delay lesion progression by approximately 1.5 years in patients with nonsubfoveal GA, compared with projected sham.
According to the companies, SYFOVRE® generated net product revenue of $587 million in 2025. Together with EMPAVELI® (pegcetacoplan), which is approved for paroxysmal nocturnal hemoglobinuria and rare kidney diseases, combined revenues reached $689 million.
For Biogen, the acquisition expands its presence in immunology and rare diseases and marks a strategic move into ophthalmology and nephrology. The company expects the transaction to support both near- and long-term growth, while leveraging Apellis’ commercial infrastructure and expertise in complement biology.
Sources: Biogen / EMA