Ruxolitinib significantly reduces the risk of thrombosis and death in polycythemia vera (PV) patients who cannot tolerate or do not respond to hydroxyurea, according to a European study that compared clinical trial and real world results. The results were presented at the 23rd Annual Congress of the European Hematology Association.
The study allows a clearer view of the benefit of ruxolitinib than previous clinical trials, most of which have permitted crossover from best available therapy to ruxolitinib.
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“When you can complement clinical trial data with real-world experiences, it can provide valuable insight into how treatments affect patients in their day-to-day lives,” said lead study investigator Alberto Alvarez-Larran, MD, of the Hematology Department, Hospital Clinic, Barcelona. “This latest research supports the use of ruxolitinib to help people with polycythemia vera gain better control of their disease when hydroxyurea is not an option.”
The researchers used propensity scores to match participants in the global phase 3 RESPONSE trial to patients in the real world Spanish Grupo Español de Enfermedades Mieloproliferativas Crónicas Filadelfia Negativas (GEMFIN) patient registry. Of the registry patients, 44% received hydroxyurea, 12% anagrelide, 10% busulfan, 6% interferon, 2% radioactive phosphorus, 11% another therapy and 26% received no cytoreductive therapy. Some patients received more than one therapy and all patients exhibited intolerance or resistance to hydroxyurea (HU) based on the modified European Leukemia Net criteria.
Before propensity score matching, the two groups differed substantially in several characteristics, including age, sex, cytopenia and JAK2 mutational status. In the unmatched analysis, patients who received ruxolitinib had 73% longer overall survival and 82% reduction in thrombosis risk compared to those who received best available therapy.
After propensity score matching, significant benefit for ruxolitinib persisted. Overall survival in the ruxolitinib group was 82% longer than in the best available therapy cohort. The risk of thrombosis was 79% lower for patients receiving ruxolitinib than those on other therapies.
The authors concluded that the significant reduction in the risk of thrombosis and mortality in the ruxolitinib group compared to the real world patients receiving other therapies “further supports the use of ruxolitinib in patients with resistance/intolerance to HU.”