Ruxolitinib Versus Best Available Therapy in Patients with Polycythemia Vera

In high-risk patients with polycythemia vera (PV), six months of first-line ruxolitinib treatment improved overall response (OS), hemoglobin and hematocrit, phlebotomy rates, spleen size, and patient-reported pruritus and fatigue severity, according to an interim analysis.

Meanwhile, best available therapy (BAT) improved platelet counts, white blood cell counts, hematocrit, and phlebotomy rates but failed to impact hemoglobin, spleen size, or symptoms.

Steffen Koschmieder, MD, of the RWTH Aachen University in Germany, and colleagues conducted the analysis because BAT had not yet been investigated as a first-line treatment of patients with untreated PV. The primary endpoint is clinicohematologic complete response (CR) rate at six months.

In the multicenter, open-label, two-arm phase IIb trial, 78 patients were randomized into either a ruxolitinib (n=44) or BAT group (n=34) and analyzed after the six-month point. Patients in the ruxolitinib arm received a starting dose of 10 mg twice daily and may increase their dose to 20 mg twice daily.

CR rates were comparable in both groups (2.3% and 2.9%, P=1.0), while OS was higher in the ruxolitinib group versus the BAT group (77.3% vs 55.9%, respectively; P=0.054). Patients on ruxolitinib also showed lower hematocrit (40.8% vs 42.1%; P=0.046), PROM symptom points for pruritus (1 vs 4; P=0.001) and fatigue (2.5 vs 5; P=0.031), and a trend toward decreased headache, abdominal discomfort, and weight loss. Meanwhile, platelet count was lower in the BAT group versus the ruxolitinib group (254/nl vs 386/nl; P=0.013). White blood cell count, spleen size, and other symptoms were comparable in both groups.

As per safety analysis, there were a total of 301 adverse events (AEs) in both treatment groups (153 AE in the ruxolitinib group and 148 in the BAT group), and there were no significant differences in the percentage of grade ≥3 AEs between both groups.

Reference

Koschmieder S, Isfort S, Teichmann L, et al. Firstline treatment with ruxolitinib versus best available therapy in patients with polycythemia vera: pre-specified interim analysis of the randomized phase 2b ruxobeat clinical trial of the german study group for myeloproliferative neoplasms (GSG-MPN). Abstract #619. Presented at the 65th ASH Annual Meeting and Exposition; December 9-12, 2023; San Diego, California.