Geron has completed 50% subject enrolment in the Phase III IMpactMF clinical trial of its telomerase inhibitor, imetelstat, to treat patients with relapsed/refractory myelofibrosis (MF).
The randomised, open-label, controlled trial intends to enrol around 320 subjects with intermediate-2 or high-risk MF who are relapsed after or refractory to previous JAK inhibitor treatment.
The trial will randomise the subjects to receive either imetelstat or the best available therapy (BAT).
Overall survival (OS) is the trial’s primary endpoint while symptom response, spleen response, progression-free survival, complete remission and partial remission among others will be evaluated as secondary endpoints.
Geron plans to report interim assessment data from the trial in the first half of 2025 with findings from the final analysis anticipated in the first half of 2026.
The company launched the Phase III IMpactMF trial based on data from the Phase II IMbark trial.
IMbark data showed that the 9.4mg/kg dose of imetelstat given every three weeks offered clinical benefits in symptom response rate with an acceptable safety profile.
The treatment also offered a median OS of 29.9 months versus 14-16 months in historical controls.
An investigational inhibitor of telomerase, imetelstat is in the developmental stage to treat hematologic malignancies.
Geron chief medical officer and executive vice-president Faye Feller said: “Reaching 50% enrolment in IMpactMF is an important milestone towards the completion of this first-of-its-kind registration-enabling trial, and we are very grateful to all of the investigators, research staff and patients who are participating.
“This is the first Phase III trial to evaluate overall survival as a primary endpoint in relapsed/refractory MF and is also the first Phase III trial investigating a telomerase inhibitor in this patient population.
“We believe that if IMpactMF confirms the clinical benefits of symptom response and overall survival observed in the Phase II IMbark study, that imetelstat could become a standard of care in relapsed/refractory myelofibrosis.”
