Imetelstat Combined With Ruxolitinib Demonstrates Promising Activity for Patients With Myelofibrosis: IMproveMF Trial
Interim results from the IMproveMF trial demonstrated imetelstat plus ruxolitinib has a manageable safety profile and promising clinical activity for patients with intermediate-1 (INT-1), intermediate-2 (INT-2), or high-risk myelofibrosis (MF).
These data were presented by John Mascarenhas, MD, Tisch Cancer Institute, New York, New York, at the 2025 American Society of Clinical Oncology (ASCO) Annual Meeting in Chicago, Illinois.
Imetelstat has previously demonstrated efficacy in MF as part of the phase 2 IMbark MF trial, as well as promising clinical activity when combined with ruxolitinib. Researchers conducted a phase 1/1b trial to evaluate the impact of imetelstat plus ruxolitinib for patients with INT-1/INT-2/high risk MF.
In this open-label, single-arm trial, patients were treated with 9.4 mg/kg of imetelstat intravenously every 28 days and were treated with ruxolitinib for at least 12 weeks prior to imetelstat administration. The primary end points were adverse events and 24-week response rate of at least 50% reduction in MD total symptom score (TSS).
Overall, 17 patients were treated with imetelstat plus ruxolitinib, of which 7 had INT-1 MF, 9 had INT-2 MF, and 1 had high risk MF. No dose-limiting toxicities were reported among patients.
Adverse events were reported among 15 patients, these included grade 3 anemia among 4 patients, grade 3 neutropenia among 3 patients, leukopenia among 2 patients, as well as abdominal pain, fatigue, epistaxis, and pneumonia among 1 patient each, respectively. From baseline, TSS reduction was found among all patients treated with imetelstat at any dose.
“In part 1 of IMproveMF, no [dose-limiting toxicities] were observed and the [recommended part 2 dose] of 9.4 mg/kg IME was determined,” the researchers concluded. “[Adverse events] were consistent with those observed in other [imetelstat] clinical trials, and preliminary efficacy was positive, demonstrating the potential of [imetelstat plus ruxolitinib] in this [patient] population with high unmet needs.”
Source:
Mascarenhas J, Bradely T, Scott B, et al. IMproveMF update: Phase 1/1B trial of imetelstat (IME)+ruxolitinib (RUX) in patients (pts) with intermediate (INT)-1, INT-2, or high-risk (HR) myelofibrosis (MF). Presented at 2025 ASCO Annual Meeting. May 30-June 3, 2025; Chicago, IL. Abstract 6515.
