How effective is Rytelo (Imetelstat)?

On June 6, 2024, The U.S. Food and Drug Administration (FDA)approvedRytelo (Imetelstat), which isAn oligonucleotide telomerase inhibitor for use in adults with low-to-moderate risk myelodysplastic syndrome (MDS) who have transfusion-dependent anemia requiring 4 or more red blood cell units for more than 8 weeks and who are unresponsive or have lost response to or are ineligible for erythropoiesis-stimulating agents (ESAs).

The efficacy of Rytelo was evaluated in IMerge (NCT02598661) a randomized (2:1), double-blind, placebo-controlled, multicenter trial in 178 patients with myelodysplastic syndrome. Patients received 7.1 mg/kg of Rytelo or placebo as an intravenous infusion during 28-day treatment cycles until disease progression or unacceptable toxicity. Randomization was stratified according to previous red blood cell (RBC) transfusion volume and International Prognostic Scoring System (IPSS) risk group. All patients received supportive care, including red blood cell transfusions.

Efficacy was determined based on the proportion of patients achieving ≥8 weeks and ≥24 weeks of red blood cell transfusion independence (RBC-TI) after a median follow-up of 19.5 months in the Rytelo group and 17.5 months in the placebo group. Defined as the absence of red blood cell transfusion during any 8 consecutive weeks and any consecutive 24 weeks, respectively, from randomization to the start of subsequent anticancer treatment, the incidence of RBC-TI for ≥8 weeks was 39.8% (95% CI, 30.9, 49.3) in the Rytelo group and 15% (95% CI, 7.1 - 26.6) in the placebo group (p value <0.001). The incidence of RBC-TI at ≥24 weeks was 28% (95% CI, 20.1-37) in the Rytelo group and 3.3% (95% CI, 0.4-11.5) in the placebo group (p value <0.001).