A Review of Real-World Experience With Ruxolitinib for Myelofibrosis

Myelofibrosis (MF) is a rare myeloproliferative neoplasm characterized by progressive bone marrow fibrosis and splenomegaly. Ruxolitinib is the standard-of-care first-line treatment option for MF. This review summarizes real-world effectiveness and safety of ruxolitinib in more than 4500 patients with MF from real-world settings, including expanded-access and phase 4 trials, as well as registry, postmarketing, and retrospective studies in the 10 years since regulatory approval. Consistent with results from the phase 3 COMFORT trials, real-world evidence supports the effectiveness of ruxolitinib in improving splenomegaly and MF symptoms while significantly increasing overall survival. Real-world safety data have also been aligned with results from the COMFORT trials. Transient anemia, thrombocytopenia, and infections are the most frequently observed adverse events (AEs) but rarely required ruxolitinib discontinuation. Other nonhematologic AEs are generally mild, and grade ≥ 3 events rarely occur. Importantly, real-world evidence also supports the effectiveness of ruxolitinib in patient groups that were poorly represented in clinical trials, including those with lower-risk MF, those presenting with thrombocytopenia or anemia, and those who have previously discontinued ruxolitinib treatment. Finally, cost-effectiveness analyses show ruxolitinib to be cost-effective in Europe and North America. Taken together, real-world studies reinforce the efficacy, safety, and cost-effectiveness of ruxolitinib for the treatment of patients with MF, supporting results from prospective clinical trials. Furthermore, they demonstrate the clinical benefit of ruxolitinib in patient subgroups poorly represented in clinical trials and the value of dose modifications or re-treatment after interruptions to optimize outcomes.