Angelini Pharma agreed to buy Catalyst Pharmaceuticals in a $4.1 billion all-cash deal, aiming to expand its rare neurology portfolio and establish a more direct U.S. commercial presence. The transaction values Catalyst at $31.50 per share, representing a premium to the period before deal rumors surfaced and is expected to close in the third quarter of 2026. Catalyst brings three marketed therapies, including Firdapse for Lambert-Eaton myasthenic syndrome and Agamree for Duchenne muscular dystrophy. Catalyst’s Fycompa rights also add an epilepsy franchise component. In 2025, the portfolio generated $589 million in combined sales, with growth reported year over year. Angelini said the acquisition supports its transformation toward brain health and rare neuro medicines, pairing Catalyst’s commercialization footprint with Angelini’s development plans. The deal underscores ongoing pharma appetite for packaged rare-disease revenue streams plus pipeline expansion.