Ipsen (Euronext: IPN) has completed its acquisition of Kartos Therapeutics, adding Phase III MDM2 inhibitor navtemadlin to its oncology pipeline and giving the France-based biopharmaceutical company a potential new hematology franchise ahead of a registrational data readout expected in 2027.
Under the definitive merger agreement announced June 29, 2026, Ipsen paid Kartos shareholders USD 450 million at closing. Shareholders are eligible for up to USD 1.3 billion in additional regulatory and sales-based milestone payments, bringing total potential consideration to USD 1.75 billion. Ipsen said the transaction is expected to become accretive to core operating income from 2029, with limited dilution to its 2026 full-year guidance.
Navtemadlin is an oral MDM2 inhibitor designed to restore p53 tumor-suppressor activity in TP53 wild-type cells. The candidate is being evaluated as an add-on to ruxolitinib in patients with myelofibrosis who have had a suboptimal response to the JAK inhibitor.
The global Phase III POIESIS trial is enrolling more than 600 patients across more than 250 sites, with topline results expected in 2027. Earlier Phase Ib/II data in 19 patients showed that 42% achieved at least a 25% reduction in spleen volume at Week 24, while 71% of evaluable patients achieved a reduction of at least 20% in driver variant allele frequency, according to Kartos.