Biogen Completes $5.6B Apellis Pharmaceuticals Acquisition May 14, 2026 — Brings Cyclic Peptide Pegcetacoplan (EMPAVELI / SYFOVRE) With $689M 2025 Net Revenue Into the Growth Portfolio
Biogen (Nasdaq: BIIB) completed its $5.6B acquisition of Apellis Pharmaceuticals on May 14, 2026 after the May 13 tender offer closed at 82.4% of outstanding common stock at $41 per share in cash plus contingent value rights (up to $4 per share tied to SYFOVRE global net sales milestones). The transaction brings two commercialized peptide-based products into Biogen's portfolio: pegcetacoplan (EMPAVELI), a pegylated cyclic 13-amino-acid peptide complement C3 inhibitor approved for paroxysmal nocturnal hemoglobinuria (PNH) and C3 glomerulopathy / immune complex-membranoproliferative glomerulonephritis; and SYFOVRE, the intravitreal pegcetacoplan formulation for geographic atrophy secondary to age-related macular degeneration. Combined 2025 net product revenue was $689M. Biogen expects the deal to be Non-GAAP EPS accretive in 2027 and to materially increase Biogen's compound annual growth rate through end of decade. The deal restores a meaningful peptide-modality presence to Biogen's portfolio.