We report the two-year end-of-study results from the phase 2 COMBI II clinical trial (#EudraCT2018-004150-13) investigating the combination treatment of ruxolitinib and low-dose pegylated interferon-α2a in patients with newly diagnosed polycythemia vera. The primary outcome was safety and key secondary endpoints were efficacy, based on hematological parameters, quality of life measurements, and JAK2V617F variant allele frequency (VAF). We used the 2013 ELN and IWG-MRT remission criteria. The remission criteria included remissions in symptoms, splenomegaly, peripheral blood counts, and bone marrow. We included 25 patients with PV with a median age of 70 years; 5 of those had prior thromboembolic events and three had CT-verified splenomegaly. Two patients stopped both study drugs, one of these due to progression to post-PV myelofibrosis; only that patient had a grade 3 infection. No events of herpes zoster infections were observed. No patients discontinued treatment due to psychiatric symptoms. The peripheral blood cell count remission rate was 92% at 24 months. Using the 2013 ELN and IWG-MRT remission criteria, 14 (56%) achieved remission at 24 months; 3 (12%) achieved complete remission, and 11 (44%) achieved partial remission. The following items from the Myeloproliferative Neoplasm Symptom Total Symptom Score were significantly reduced: abdominal discomfort, night sweats, itching, and bone pain. The median JAK2V617F VAF decreased from 47% (95%CI, 35-59%) to 7% (95%CI, 3-15%), and 60% of patients achieved molecular remission. In conclusion, combination treatment improved cell counts; bone marrow cellularity, and fibrosis; and decreased JAK2V617F VAF; with acceptable toxicity in patients with polycythemia vera. EudraCT2018-004150-13.

Combination Therapy with Ruxolitinib and Pegylated Interferon-alpha2a in Newly Diagnosed Patients with Polycythemia Vera.