Geron Corporation announced publication in The Lancet of results from the IMerge Phase 3 trial investigating imetelstat versus placebo in patients with lower risk myelodysplastic syndromes (MDS) relapsed/refractory or ineligible for erythropoiesis stimulating agents (ESAs). The publication is available online and will be available in print at a later date. Imetelstat is currently under regulatory review by the U.S. Food and Drug Administration (FDA) and by the European Medicines Agency (EMA) for approval in transfusion dependent anemia in patients with lower risk MDS who have failed to respond or have lost response to or are ineligible for ESAs.

As previously reported, in the IMerge Phase 3 clinical trial, the primary endpoint of red blood cell transfusion independence (TI) for at least 8 consecutive weeks was significantly higher with imetelstat vs. best supportive care (placebo) (p<0.001), with median TI duration approaching one year for imetelstat 8-week TI responders. Mean hemoglobin levels in imetelstat-treated patients increased significantly (p<0.001) over time compared to placebo patients.

For patients achieving 8-week TI, median increases in hemoglobin were 3.6 g/dL for imetelstat and 0.8 g/dL for placebo. Significant and clinically meaningful efficacy results were achieved across key MDS subgroups irrespective of ring sideroblast (RS) status, baseline transfusion burden and IPSS risk category. Patient-reported outcomes (PRO) data reported a sustained meaningful improvement in fatigue for imetelstat-treated patients vs.

placebo. Treatment with imetelstat vs. placebo led to greater reduction in variant allele frequency (VAF) in certain genes commonly mutated in MDS, which was associated with longer TI duration and increase in hemoglobin levels.

Consistent with prior imetelstat clinical experience, the most common adverse events were thrombocytopenia and neutropenia that were manageable and of short duration. The Phase 3 portion of the IMerge Phase 2/3 study is a double-blind, 2:1 randomized, placebo-controlled clinical trial to evaluate imetelstat in patients with IPSS Low or Intermediate-1 risk (lower risk) transfusion dependent MDS who were relapsed after, refractory to, or ineligible for, erythropoiesis stimulating agent (ESA) treatment, had not received prior treatment with either a HMA or lenalidomide and were non-del(5q). To be eligible for IMerge Phase 3, patients were required to be transfusion dependent, defined as requiring at least four units of packed red blood cells (RBCs), over an eight-week period during the 16 weeks prior to entry into the trial.

The primary efficacy endpoint of IMerge Phase 3 is the rate of red blood cell transfusion independence (RBC-TI) lasting at least eight weeks, defined as the proportion of patients without any RBC transfusion for at least eight consecutive weeks since entry to the trial (8-week TI). Key secondary endpoints include the rate of RBC-TI lasting at least 24 weeks (24-week TI), the duration of TI and the rate of hematologic improvement erythroid (HI-E), which is defined under 2006 IWG criteria as a rise in hemoglobin of at least 1.5 g/dL above the pretreatment level for at least eight weeks or a reduction of at least four units of RBC transfusions over eight weeks compared with the prior RBC transfusion burden. A total of 178 patients were enrolled in IMerge Phase 3 across North America, Europe, Middle East and Asia.