Biogen agreed to acquire Apellis Pharmaceuticals for roughly $5.6 billion in cash, adding two commercial products and immunology nephrology expertise to its portfolio. The deal includes Apellis’ complement inhibitor Syfovre for geographic atrophy due to AMD and Empaveli for rare complement-mediated kidney diseases. Financial terms call for $41 per Apellis share plus up to additional consideration via contingent value rights linked to Syfovre global net sales milestones. Biogen expects the transaction to provide immediate revenue and support pipeline expansion, including launch readiness for its investigational felzartamab program targeting CD38+ plasma cells. Analysts and investors are likely to focus on integration and whether Biogen’s commercial infrastructure can translate complement-franchise growth into continued immunology leadership, particularly across nephrology and ocular indications. The acquisition also reflects ongoing consolidation as large biotech and pharma players build breadth in late-stage immunology and rare disease, rather than relying solely on early-stage discovery to fill pipeline gaps.