Geron is discontinuing its Phase 3 IMpactMF trial of imetelstat in patients with myelofibrosis whose disease had relapsed after, or failed to respond to, a JAK inhibitor. The decision follows a recommendation from an independent monitoring committee, which concluded the study was unlikely to meet its primary goal of improving overall survival.
The company said the trial showed no new safety signals that would change imetelstat’s known safety profile. Geron plans to analyze the results further and share findings with the scientific community later.
Key details
- The study tested whether imetelstat could improve overall survival compared with best available therapy in patients with intermediate-2 or high-risk myelofibrosis.
- It enrolled 327 patients, who were assigned in a 2-to-1 ratio to imetelstat or a control group. Patients receiving imetelstat were given an intravenous dose every three weeks.
- The monitoring committee’s recommendation was based on the likelihood of meeting the survival endpoint. Geron has not yet provided a detailed analysis of the trial results.
- No new safety concerns were identified that would require a change to imetelstat’s known safety profile or additional safety monitoring.
- Geron’s stated commercial focus remains RYTELO, the imetelstat product approved in the U.S. and European Union for certain patients with lower-risk myelodysplastic syndromes. The company said it intends to grow U.S. demand and broaden access for eligible patients outside the U.S.
What changes
The discontinuation ends Geron’s Phase 3 study of imetelstat in this relapsed or refractory myelofibrosis population. The committee’s assessment means the trial was unlikely to demonstrate the planned overall-survival benefit; it does not, by itself, provide a detailed account of the treatment’s effects or establish the reasons for the result. Geron says those findings will be assessed in a fuller data analysis.