Interferon-alpha for treating polycythemia vera yields improved myelofibrosis-free and overall survival

Interferon-alpha (rIFN alpha) is the only disease-modifying treatment for polycythemia vera (PV), but whether or not it prolongs survival is unknown. This large single center retrospective study of 470 PV patients compares the myelofibrosis-free survival (MFS) and overall survival (OS) with rIFN alpha to two other primary treatments, hydroxyurea (HU) and phlebotomy-only (PHL-O). The median age at diagnosis was 54 years (range 20-94) and the median follow-up was 10 years (range 0-45). Two hundred and twenty-nine patients were women (49%) and 208 were high-risk (44%). The primary treatment was rIFN alpha in 93 (20%), HU in 189 (40%), PHL-O in 133 (28%) and other cytoreductive drugs in 55 (12%). The treatment groups differed by ELN risk score (p < 0.001). In low-risk patients, 20-year MFS for rIFN alpha, HU, and PHL-O was 84%, 65% and 55% respectively (p < 0.001) and 20-year OS was 100%, 85% and 80% respectively (p = 0.44). In high-risk patients, 20-year MFS for rIFN alpha, HU, and PHL-O was 89%, 41% and 36% respectively (p = 0.19) and 20-year OS was 66%, 40%, 14% respectively (p = 0.016). In multivariable analysis, longer time on rIFN alpha was associated with a lower risk of myelofibrosis (HR: 0.91, p < 0.001) and lower mortality (HR: 0.94, p = 0.012). In conclusion, this study supports treatment of PV with rIFN alpha to prevent myelofibrosis and potentially prolong survival.

Automated summary

The study suggests that treatment of PV with rIFN alpha can reduce the risk of myelofibrosis and mortality, especially in high-risk patients.