Imetelstat (telomerase inhibitor) doubles mOS vs real‑world BAT after ruxolitinib in R/R myelofibrosis

Imetelstat (IME) is a first-in-class telomerase inhibitor evaluated in IMbark (Phase 2; NCT02426086) in intermediate‑2/high‑risk myelofibrosis after Janus kinase inhibitor (JAKi) relapse/refractoriness. In this updated post hoc comparison versus a closely matched Moffitt real‑world cohort diagnosed before 2016 and treated with best available therapy (BAT) after ruxolitinib discontinuation, IMbark IME patients (n=59) had median OS 30.7 months (95% CI 25.5–36.9) vs 15.4 months (13.1–30.5) with RW BAT (n=54; HR 0.512, p=.003) with similar findings after propensity weighting (ATO/sIPTW); follow-up was ~46–48 months. Importantly, RW outcomes improved over time (mOS 34.2 months after 2016; 39.8 months after 2019), consistent with faster ruxolitinib initiation and shorter ruxolitinib duration (earlier switching to next-line JAKi/clinical trials) — meaning “BAT” benchmarks from older eras likely underestimate today’s post‑RUX survival (historically ~13 months after RUX discontinuation in pre–2L-JAKi eras).