Biogen agreed to buy Apellis Pharmaceuticals for about $5.6 billion, extending its strategy to add commercialized products and expand in nephrology and immunology. Apellis brings approved complement medicines Empaveli and Syfovre, as well as the company’s kidney program led by HI-Bio in pivotal development. The transaction is positioned as an immediate revenue and launch-readiness boost for Biogen while it continues building next-wave pipelines, including felzartamab under its HI-Bio platform. Biogen also indicated the combined cash flow would improve leverage optics and create capacity for further deals. From an industry perspective, the tie-up reinforces how late-stage biopharma consolidation is increasingly driven by revenue durability plus a pipeline handoff into areas where incumbents are competing for share. Investors will likely focus on integration risk, preservation of Apellis’s commercial momentum, and how quickly Biogen can translate HI-Bio’s clinical data into registrational plans.