Regeneron Says Ongoing Phase 1/2 Ovarian Cancer Trial With Ubamatamab Showed High Rate of Durable Responses

12:15 PM EDT, 10/01/2026 (MT Newswires) -- Regeneron Pharmaceuticals' (REGN) data from its ongoing phase 1/2 trial evaluating ubamatamab in patients with a biologically distinct variant of ovarian cancer showed a high rate of durable responses, it said Thursday. The company said that 11 patients who received 800 mg of ubamatamab monotherapy demonstrated a 73% objective response rate. The patients also showed an 11-month median progression-free survival and a 9-month median duration of response, it said. The trial is currently evaluating ubamatamab alone and in combination with Libtayo in adult patients with recurrent platinum-resistant ovarian cancer and other recurrent MUC16-expressing cancers, Regeneron said. Shares of the company were down 4% in Thursday's trading. Price: 727.65, Change: -30.62, Percent Change: -4.04