Ipsen agreed to acquire Kartos Therapeutics in a deal valued at $1.75 billion total, including $450 million upfront, to bring navtemadlin—an investigational oral MDM2 inhibitor—into its late-stage hematology pipeline. Navtemadlin is being studied as an add-on therapy to ruxolitinib in intermediate/high-risk TP53 wild-type myelofibrosis with a suboptimal response to standard JAK inhibition. Kartos’ POIESIS Phase 3 program for navtemadlin is designed to enroll more than 600 patients across over 250 sites, with a potential launch as early as 2028 cited by the companies. Ipsen positioned the acquisition as a strategy to strengthen its late-stage oncology offerings. The deal underscores how cash-rich pharma continues to prioritize Phase 3 assets to fill risk-reward gaps created by earlier oncology attrition.