Ipsen to acquire Kartos Therapeutics, expanding hemato-oncology late-stage pipeline

PARIS, FRANCE AND REDWOOD CITY, U.S. , 29 JUNE 2026 - Ipsen (Euronext: IPN; ADR: IPSEY) and Kartos Therapeutics, announced today they have entered into a definitive merger agreement under which Ipsen has agreed to acquire Kartos Therapeutics. The acquisition adds navtemadlin, an investigational MDM2 inhibitor designed to restore the natural tumor-suppressing function of p53, a critical tumor-suppressor in myelofibrosis. Data show strong therapeutic potential of navtemadlin for intermediate and high-risk TP53 wild-type (wt) myelofibrosis as an add-on treatment for patients with a suboptimal response to standard of care ruxolitinib.