Real-World Dosing Patterns of Ruxolitinib in Patients With Polycythemia Vera Who Are Resistant to or Intolerant of Hydroxyurea

Introduction: Approximately one-quarter of patients with polycythemia vera become resistant to and/or intolerant of hydroxyurea. This analysis characterizes reasons patients were switched from hydroxyurea to ruxolitinib and describes ruxolitinib dosing patterns and outcomes in real-world clinical practice.

Patients and methods: This medical chart review of United States community hematology/oncology practices in the Cardinal Health Oncology Provider Extended Network included patients with polycythemia vera who were ≥18 years old, received hydroxyurea for ≥3 months, started ruxolitinib between January 1, 2015 and December 31, 2016, and had ≥2 visits during the subsequent 6 months. Clinical data were collected at predefined intervals from diagnosis to last provider visit.

Results: Providers identified 249 patients for inclusion. jcauses of hydroxyurea discontinuation were resistance (78%; frequently for hematocrit ≥45% [79%]) and intolerance (28%; frequently for nausea/vomiting [50%]). Initial ruxolitinib dosing was 10 mg twice daily (recommended dose) in 131 patients (53%). Among these patients, median treatment duration was 29.2 months, 35 (27%) had dose modification (increase, n = 24; decrease, n = 11) and 4 had interruptions within 6 months. The most common reason for dose increase was continued need for phlebotomy (46%); 6 patients had dose reductions owing to reduced platelets. Hematocrit control at initiation and during the first 6 months of ruxolitinib treatment was 15% and 63%, respectively.

Conclusion: Most patients initiated ruxolitinib upon hydroxyurea resistance. Approximately half initiated ruxolitinib at the recommended dose, 27% of whom experienced dosing modifications within the first 6 months. After switching to ruxolitinib, most patients achieved hematocrit control and continued treatment for extended time frames.