Angelini Pharma will acquire Catalyst Pharmaceuticals in an all-cash deal valued at $4.1 billion, adding a portfolio of FDA-approved rare neurology drugs. The transaction includes Catalyst’s Firdapse for Lambert-Eaton myasthenic syndrome, Agamree for Duchenne muscular dystrophy, and Fycompa for certain seizure disorders, among other rights. Angelini will pay $31.50 per share, a 21% premium to Catalyst’s closing price ahead of deal speculation. Catalyst generated $589 million in 2025 revenue, and Angelini said the deal is expected to close in the third quarter of 2026. The acquisition also marks Angelini’s stated effort to build a U.S. commercial base in brain health and rare neurological diseases, aligning Catalyst’s established infrastructure with Angelini’s longer-term strategy to expand in the U.S. market.