Biogen agreed to acquire Apellis Pharmaceuticals in a deal valued at $5.6 billion, a move framed as accelerating Biogen’s expansion in nephrology and complementing its existing late-stage kidney-focused pipeline strategy. The acquisition comes after Biogen’s prior immunology expansion steps, including its purchase of Human Immunology Biosciences, and is expected to build out programs connected to a HI-Bio drug currently in pivotal testing across kidney indications. Biogen executives said the combined cash flow profile could support both debt leverage reduction and additional strategic activity. From an industry standpoint, the transaction underscores how large neuro and specialty biopharma are using M&A to deepen modality depth and broaden therapeutic reach beyond legacy platforms. For Apellis, the deal provides scale resources and an integration path that can accelerate late-stage decision-making and commercialization planning.