Biogen agreed to acquire Apellis Pharmaceuticals for about $5.6 billion, gaining two commercial immunology assets and strengthening its pipeline ahead of planned launches. The transaction includes the approved geographic atrophy therapy Syfovre, which generated $587 million in sales last year, according to Biogen. The deal also expands Biogen’s commercial footprint in immunology-driven ophthalmic disease, while setting up potential platform and clinical development synergies around complement-pathway biology. For Apellis, the acquisition price gives shareholders $41 per share upfront, with additional contingent value tied to sales thresholds related to Syfovre. The acquisition caps a broader pattern of large-company consolidation in immunology as developers with approved assets seek scale and portfolio depth.