Biogen agreed to acquire Apellis Pharmaceuticals for about $5.6 billion, adding two marketed immunology assets and bolstering its late-stage pipeline. The companies’ deal values Apellis at $41 per share, with stockholders eligible for additional contingent value rights tied to sales thresholds for Syfovre. Apellis’ commercial portfolio includes Syfovre (pegcetacoplan) for geographic atrophy secondary to age-related macular degeneration, approved in the U.S. in 2023. Biogen also expects to leverage Apellis’ internal expertise as it prepares additional program launches, including felzartamab. Analysts and investors are watching whether the combined company can sustain growth as complement competition evolves, with the acquisition positioning Biogen to expand its immunology platform at scale.