Biogen agreed to acquire Apellis Pharmaceuticals for $5.6 billion, aiming to accelerate its nephrology expansion. The deal comes after Biogen’s immunology push and is tied to an HI-Bio drug in pivotal testing across three kidney conditions. The transaction highlights continuing consolidation in immunology-adjacent specialty franchises, as large-cap companies look to refill late-stage pipelines and diversify across organ systems. For Apellis, the acquisition provides scale for development and commercialization, especially as complement biology remains a high-interest area. Industry impact centers on how Biogen allocates capital to kidney indications and how quickly the HI-Bio program can progress post-close, influencing competitive positioning against other complement and inflammation pathways.