Ruxolitinib, an oral JAK1 and JAK2 inhibitor, in myelofibrosis.

INTRODUCTION: Myelofibrosis (MF) is a debilitating hematologic malignancy characterized by progressive splenomegaly, burdensome symptoms, cytopenias and shortened survival. Chronic alterations in Janus-associated kinase-signal transducer and activator of transcription (JAK-STAT) signaling have been identified in the pathogenesis of MF, making this pathway a target for drug development. Ruxolitinib is the first JAK1 and JAK2 inhibitor to be approved by the US Food and Drug Administration. AREAS COVERED: This review describes the characteristics of MF, the current therapeutic options and need for effective therapies, the contribution of aberrant JAK-STAT signaling to various disease-specific manifestations and the pharmacodynamics, pharmacokinetics, efficacy and tolerability of ruxolitinib. Articles describing MF disease burden and results of ruxolitinib pre-clinical and clinical trials were identified and summarized. EXPERT OPINION: Conventional MF treatments alleviate some MF symptoms but have limited efficacy, do not modify the natural history of the disease and are not approved for MF. The JAK1 and JAK2 inhibitor ruxolitinib has shown promising results in pre-clinical and clinical trials. In Phase III trials, ruxolitinib was shown to reduce splenomegaly and improve MF-related symptoms. Recent evidence also suggests that ruxolitinib may improve survival. The most common adverse events were anemia and thrombocytopenia, which were managed with dose adjustments (or red blood cell transfusions for anemia).