Clinical trials

In addition to our two Phase 3 trials for lower-risk myelodysplastic syndromes (MDS) and myelofibrosis (MF), we are exploring imetelstat’s potential in additional indications and in combination with current standard of care therapies through early-stage trials, and have a discovery research program to identify a next generation telomerase inhibitor.

Geron sponsored trials

IMerge logo

IMerge Phase 3 is designed to confirm the results from IMerge Phase 2, and to support potential registration of imetelstat in lower-risk MDS. The study is a double-blind, 2:1 randomized, placebo-controlled clinical trial in approximately 170 patients with lower-risk MDS. The trial will evaluate an improvement in the rate of red blood cell transfusion independence (RBC-TI) and other measures of improvements in the anemia of participants treated with imetelstat compared to placebo. IMerge Phase 3 is closed to new patient enrollment.


IMpactMF logo

IMpactMF, our Phase 3 clinical trial in relapsed/refractory MF with registrational intent, is designed as an open label, 2:1 randomized, controlled clinical trial of imetelstat to evaluate a potential improvement in overall survival compared to best available therapy. The trial plans to enroll approximately 320 patients with intermediate-2 or high-risk MF who are relapsed or refractory to treatment with a janus associated kinase (JAK) inhibitor. IMpactMF is open for screening and enrollment.


IMproveMF logo

IMproveMF is a two-part Phase 1 clinical trial evaluating imetelstat in combination with ruxolitinib in patients with Intermediate-1, Intermediate-2 or high-risk frontline MF. In Part 1 of the study, the objective is to identify a safe dose of the combination treatment. In Part 2, the objective is to confirm the dose of the combination treatment of imetelstat and ruxolitinib and evaluate efficacy. IMproveMF is open for screening and enrollment.


Investigator led trials


IMpress is a Phase 2 clinical trial evaluating imetelstat as a single agent in patients with acute myeloid leukemia (AML) or high-risk MDS, who are relapsed/refractory/intolerant to hypomethylating agents, or HMAs. The objective of this trial is to evaluate the efficacy of single agent imetelstat in this patient population. The primary endpoint of this trial is overall response rate.



TELOMERE is a planned Phase 1/2 clinical trial evaluating imetelstat in patients with relapsed/refractory AML. The trial is designed to test two distinct combinations of imetelstat and venetoclax or imetelstat and azacitidine. The primary objective of the Phase 1 portion is to identify a safe dose of each of the combinations. The primary objective of the Phase 2 portion of the study is overall response rate for each of the combination regimens. TELOMERE is expected to begin after an appropriate dose for single agent imetelstat in AML has been identified in the IMpress study.

Preclinical studies and discovery research program

Preclinical Lymphoid Hematologic Malignancy Program

Pre-clinical data suggests that multiple lymphoid malignancies have higher telomerase activity and shorter telomeres when compared to normal healthy cells. Thus, we believe a telomerase inhibition approach may find utility in this disease setting. Based on this scientific hypothesis, this preclinical research project at MD Anderson Cancer Center is evaluating the potential application of imetelstat in lymphoid hematologic malignancies.

Next Generation Telomerase Inhibitor Discovery Program

This discovery program’s goal is to identify a small molecule lead compound as a potential next generation telomerase inhibitor. If such a compound is identified, preclinical experiments are planned, which are intended to serve as a basis for potential future clinical testing.

To learn more about clinical trials, please visit To see clinical trials that are currently underway and to find out if a study is enrolling patients with your condition and in your area, please visit If you have any questions regarding ongoing clinical trials of imetelstat, please contact