Biogen agreed to acquire Apellis Pharmaceuticals in a deal valued at about $5.6 billion, securing two already-commercialized immunology franchises. The acquisition includes kidney drug Empaveli (pegcetacoplan) and complement therapy Syfovre for geographic atrophy secondary to age-related macular degeneration. Under the terms, Biogen will pay $41 per Apellis share. Apellis shareholders can also receive additional payments via a contingent value right tied to Syfovre global net sales milestones, adding potential upside if sales targets are met. The transaction positions Biogen to bolster nephrology offerings while supporting its broader launch readiness, including the company’s felzartamab program—an investigational CD38+ plasma cell–targeting antibody with FDA breakthrough therapy designation for select immune-mediated conditions. For the biotech sector, the move underlines continued pharma preference for immunology assets with existing revenue and clear regulatory histories—especially in complement pathways where follow-on clinical programs can leverage established safety and commercial infrastructure.