Multicenter phase 2-trial of addition of ropeginterferon to standard therapy for low-risk polycythemia vera

A phase 2 trial at 31 centers in Italy randomized patients with low-risk polycythemia vera to phlebotomy plus ropeginterferon alfa-2b (‘ropeg’, 100 μg every two weeks) or phlebotomy only. Primary end point was maintenance of the median hematocrit value less than or equal to 45% for 12 months in the absence of progressive disease. This end point was met in 81% of the ropeg group versus 51% of the standard group (p<0.001). Responders continued the assigned treatment until month 24 and maintained response in 83% and 59%, respectively (p=0.02). Ropeg responders less frequently experienced moderate or severe symptoms (33% versus 67% in the standard group) and palpable splenomegaly (14% versus 37%0 and showed normalization of ferritin levels and blood counts. Discontinuation of ropeg due to adverse events occurred in 10.9% of patients.