Ruxolitinib in patients with polycythemia vera resistant and/or intolerant to hydroxyurea: European observational study.

Background: Hydroxyurea (HU) is a commonly used first-line treatment in patients with polycythemia vera (PV). However, approximately 15%-24% of PV patients report intolerance and resistance to HU.

Methods: This phase IV, European, real-world, observational study assessed the efficacy and safety of ruxolitinib in PV patients who were resistant and/or intolerant to HU, with a 24-month follow-up. The primary objective was to describe the profile and disease burden of PV patients.

Results: In the 350 enrolled patients, 70% were >60 years old. Most patients (59.4%) had received ≥1 phlebotomy in the 12 months prior to the first dose of ruxolitinib. Overall, 68.2% of patients achieved hematocrit control with 92.3% patients having hematocrit <45% and 35.4% achieved hematologic remission at month 24. 85.1% of patients had no phlebotomies during the study. Treatment-related adverse events were reported in 54.3% of patients and the most common event was anemia (22.6%). Of the 10 reported deaths, two were suspected to be study drug-related.

Conclusion: This study demonstrates that ruxolitinib treatment in PV maintains durable hematocrit control with a decrease in the number of phlebotomies in the majority of patients and was generally well tolerated.