Biogen agreed to acquire Apellis Pharmaceuticals for $5.6 billion, positioning the deal as a way to accelerate expansion in immunology and rare disease. The acquisition adds commercialized medicines—Empaveli and Syfovre—into Biogen’s portfolio and strengthens the company’s launch readiness for its HI-Bio pipeline. The excerpt describes the financial structure as including contingent value rights tied to Syfovre net sales milestones. Biogen’s rationale also focuses on leveraging immediate revenue contribution to maintain financial flexibility for future strategic transactions. For biotech professionals, the key impact is another large-tape consolidating move in immunology and rare disease, with incumbents using cash-flow accretion to fund pipeline execution and transformation strategy.