Geron Announces IMerge Phase 3 Presentations at ASH Highlighting Significant Durability of Transfusion Independence and Breadth of Effect Across MDS Subgroups with Imetelstat in Lower Risk MDS - Seite 2

“Impact of Mutational Status on Clinical Response to Imetelstat in Patients with Lower Risk Myelodysplastic Syndromes in the IMerge Phase 3 Study”

This poster evaluates the impact of MDS-associated mutations on clinical efficacy of imetelstat for the 165 of 178 patients for whom mutation data were available. Results showed that in patients who had more than one mutation detected at baseline and more than two mutations at baseline, imetelstat significantly improved the 8-week and 24-week RBC-TI response rates compared with placebo. A significantly higher percentage of imetelstat-treated than placebo-treated patients with baseline mutations in SF3B1, a gene commonly mutated in MDS, achieved 8- and 24-week RBC-TI. RBC-TI responses in patients receiving imetelstat occurred regardless of the presence of mutations associated with poor prognosis or the number of mutations. This analysis suggests clinical benefit of imetelstat across different molecularly defined subgroups and independent of the underlying molecular mutation pattern.

“Durable Continuous Transfusion Independence With Imetelstat in IMerge Phase 3 for Patients With Heavily Transfused Non-Del(5q) Lower-Risk Myelodysplastic Syndromes Relapsed/Refractory to or Ineligible for Erythropoiesis-Stimulating Agents”

This poster reports on the patients enrolled in IMerge Phase 3 who achieved one-year or greater continuous RBC-TI response, which included 17.8% of imetelstat-treated patients (21/118; 95% CI, 11.4-25.9) and 1.7% of patients on placebo (1/60; 95% CI, 0-8.9). One-year RBC-TIs were achieved by 44.7% of 8-week RBC-TI responders and 63.6% of 24-week RBC-TI responders. During the one-year or greater RBC-transfusion-free interval, RBC transfusion burden was reduced from a baseline range of 4-9 units and hemoglobin improved a median of 5.2 g/dL. Imetelstat 1-year RBC-TI responders had a median duration of RBC-TI of 123 weeks (95% CI, 80.4-NE) and no patients progressed to acute myeloid leukemia (AML). At the time of data cutoff (May 10, 2023), 13 1-year RBC-TI responders receiving imetelstat and one patient receiving placebo were ongoing on treatment. Of the 18 imetelstat one-year responders for whom mutational data were available, complete elimination of certain mutational clones was observed in 10 of 18 patients (55.5%) for whom mutational data were available and 13 (72.2%) achieved greater than or equal to 50% SF3B1 variant allele frequency (VAF) reduction, including 7 patients with complete elimination of VAF. For these one-year RBC-TI responders and consistent with the overall safety profile for patients on IMerge Phase 3, Grade 3-4 thrombocytopenia and neutropenia occurred in 14 (67%) and 20 (95%) patients, with a mean duration of 1.78 (1.58) and 2.25 (2.48) weeks, respectively. 81% of Grade 3-4 neutropenia and 89% of Grade 3-4 thrombocytopenia were reversible to Grade 2 or below within 4 weeks.