Geron Corporation announced on October 28, 2026, that it has decided to discontinue the Phase 3 IMpactMF clinical trial evaluating imetelstat in patients with JAK inhibitor relapsed/refractory myelofibrosis. This decision was made following a recommendation from the independent Data Monitoring Committee (DMC), which advised that the trial was unlikely to meet its primary endpoint of overall survival.
The IMpactMF trial evaluated 327 patients with intermediate-2 or high-risk myelofibrosis who had relapsed or were refractory to a JAK inhibitor. Patients were randomized 2:1 in an open-label, controlled trial to receive imetelstat or best available therapy. Patients in the imetelstat arm received a dose of 9.4 mg/kg intravenously every three weeks.
Geron stated that no new safety signals were observed during the trial that would change the known safety profile of imetelstat. The company noted that a detailed analysis of the data will be conducted, and study findings will be shared with the scientific community at a future date.
Despite the discontinuation of the IMpactMF trial, Geron highlighted its commitment to growing demand for its approved medicine, RYTELO (imetelstat), in the United States and broadening access for eligible lower-risk myelodysplastic syndromes patients outside the U.S.
