Five-year follow-up of RESPONSE-2 study of ruxolitinib for inadequately controlled polycythemia vera without splenomegaly

The multinational phase 3b RESPONSE-2 study in patients with inadequately controlled polycythemia vera (PV) without splenomegaly showed superiority for ruxolitinib versus best available therapy (BAT) for the primary endpoint of hematocrit control at week 28. Five-year follow-up results of secondary endpoints have now been published. Between weeks 28 and 80, 77% of BAT patients switched over to ruxolitinib. Median hematocrit level among patients in the ruxolitinib group remained below 45%. Sixty phlebotomies were required among 74 patients in the ruxolitinib group in 260 weeks, compared with 106 phlebotomies among 75 patients in the BAT group. Five-year overall survival was 96% (95% CI 87-99) in the ruxolitinib group and 91% (80-96) in the BAT group. The authors conclude that these results support the use of ruxolitinib as second-line therapy for patients with inadequately controlled PV without splenomegaly.