Ruxolitinib Beneficial in Hydroxyurea Resistant/Intolerant Polycythemia Vera
Patients treated with ruxolitinib appeared to experience benefits in terms of hematocrit control, researchers found.
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Data presented at the 2017 American Society of Hematology Annual Meeting (ASH 2017) are confirming previous studies suggesting that patients with polycythemia vera (PV) who fail hydroxyurea and are treated with ruxolitinib may have better hematocrit control. Researchers reported that patients treated with ruxolitinib appear to experience benefits in terms of hematocrit control, hematologic remission, and reduction in spleen size.
The RESPONSE study demonstrated that this potent JAK1/2 inhibitor results in superior response rates compared with best available therapy in controlling hematocrit and improving splenomegaly and symptoms in patients with PV whose disease was inadequately controlled with hydroxyurea. Following initial trials, an expanded-access phase 3b study was conducted looking at ruxolitinib in patients who were hydroxyurea resistant/intolerant. The study included patients who had no other treatment options available and were not eligible for any ongoing clinical trial.
Timothy Devos, MD, of the Department of Hematology and Laboratory of Experimental Transplantation, Department of Microbiology and Immunology, University Hospital Leuven (UZ Leuven) in Leuven, Belgium, and colleagues examined the safety and efficacy of ruxolitinib in patients enrolled in the study who received this agent for at least 6 months or discontinued it prematurely. The researchers reported on 75 patients (median age 68 years). Among these patients, 43% were hydroxyurea resistant and 57% were hydroxyurea intolerant. The median time since the diagnosis of PV was 65.3 months.
The researchers found that 14 patients (19%) discontinued prematurely and the primary reasons included adverse events (AEs; 2%), patient decision (1%), withdrawal of consent (1%), disease progression (3%), and death (1%). The median exposure was 43.3 weeks (range 1 to 72), and the median dose intensity of ruxolitinib was 20.0 mg/day (range 8.9 to 45.4 mg/day). The researchers found that AEs resulted in a dosage change in 44% of patients.
The most common hematologic-related AE was anemia (all grades) and the most frequent nonhematologic AEs were constipation, fatigue, asthenia, headache, and pruritus. The researchers discovered at week 24 that 52 patients (69%) achieved hematocrit control and 17 patients (23%) experienced blood count remission. There were also significant reductions in spleen size among patients receiving ruxolitinib at 24 weeks.
The researchers concluded that the symptom scores, safety scores, and efficacy rates in this analysis were consistent with those seen in previous clinical trials of ruxolitinib (RESPONSE and RESPONSE-2 studies) in patients with PV.
ReferenceDevos T, Pica GM, Zerazhi H, et al. Safety and efficacy of ruxolitinib (rux) in an open-label, multicenter, expanded treatment protocol in patients (Pts) with polycythemia vera (PV) who are hydroxyurea (HU) resistant or intolerant and for whom no alternative treatments are available. Poster presentation at: 2017 American Society of Hematology Annual Meeting; December 9-12, 2017; Atlanta, GA. Abstract 2918.