Fedratinib Shows Promise in MDS/MPN Overlap Syndromes and CNL
Key claim: Fedratinib demonstrated promising efficacy and manageable safety in a phase 2 trial enrolling patients with MDS/MPN overlap syndromes (including MDS/MPN-U, MDS/MPN-RS-T, aCML) and chronic neutrophilic leukemia.
Abstract
Fedratinib (Inrebic), a JAK2-selective inhibitor, demonstrated promising efficacy with manageable safety in phase 2 trial (NCT05177211) for patients with atypical chronic myeloid leukemia, chronic neutrophilic leukemia, MDS/MPN-unclassifiable, and MDS/MPN-ring sideroblasts and thrombocytosis. Data presented at 2024 ASH Annual Meeting. At cutoff, 24 patients were enrolled.
Why this matters
MDS/MPN overlap syndromes and CNL are rare, prognostically heterogeneous entities with sparse prospective therapeutic evidence, often forcing clinicians to extrapolate from ET/PV/PMF or MDS frameworks. A phase 2 signal for fedratinib extends JAK2-selective inhibition beyond classic MPNs into these orphan subtypes, and reinforces the importance of distinguishing MPN-U from MDS/MPN-U in subtype-specific natural history tracking. If confirmed, this could meaningfully shift the treatment landscape for diseases that currently lack approved subtype-specific therapies.