Shares of Catalyst Pharmaceuticals (CPRX) are trading higher on Thursday after Angelini Pharma agreed to acquire the rare disease drugmaker for $4.1 billion, or $31.50 per share. The boards of both companies have unanimously approved the deal.

Angelini Group is a family-run company chaired by Thea Paola Angelini, a fourth-generation member of the Angelini family, and led by Sergio Marullo di Condojanni, CEO of Angelini Pharma. Catalyst, meanwhile, focuses on biopharmaceuticals for rare diseases.

Separately, Catalyst announced it has resolved patent litigation it brought against Hetero USA Inc., which had filed an Abbreviated New Drug Application to market a generic version of Firdapse (amifampridine) 10 mg tablets before Catalyst's patents expire. Firdapse is an FDA-approved medication for Lambert-Eaton myasthenic syndrome (LEMS), a rare autoimmune disorder that causes muscle weakness by affecting the neuromuscular junction.

With the acquisition and litigation behind it, Catalyst is now gearing up to report earnings on May 11, 2026. Analysts expect earnings per share of 63 cents, down from 68 cents a year ago, on revenue of $147.96 million, up from $141.42 million. The stock trades at a P/E of 18.2x, which suggests a fair valuation.

At the time of publication on Thursday, Catalyst shares were up 2.06% at $31.15, according to market data.