Interferon Alpha, the New Old Disease Modifying Agent for Philadelphia-Negative Myeloproliferative Neoplasms

Background: Despite the important progress in the research of myeloproliferative neoplasms (MPN) in the last years, treatment options are still limited. Currently, a cytoreductive approach is the backbone treatment, with hydroxyurea (HU) being the most important agent. However, this drug is not always well tolerated and seems to be associated with a potential leukemogenic effect. A valid alternative treatment is interferon alfa (IFN-α), but is reserved for selected patients due to the unfavorable toxicity profile. Furthermore, studies directly comparing IFN-α to HU are lacking, which is why we performed the so far largest Philadelphia negative (Ph-) MPN real-life analysis. Methods: From 2000 to January 2016 we prospectively assessed 63 Ph- MPN patients who received either HU at induction dosage of 25 mg/kg daily until achievement of hematologic remission, followed by maintenance therapy at 10 to 15 mg/kg daily, or IFN-α 3 MU subcutaneously three times a week. The treatment was selected based on physician9s choice. All patients were screened for molecular genetic and cytogenetic analysis at diagnosis and during treatment. Results: Between January 2000 and January 2016, 63 consecutive patients were diagnosed with Ph- MPN: 28 were affected by polycythemia vera (PV) and 35 by essential thrombocytosis (ET). Fifteen patients with PV (54%) and 20 with ET (57%) were treated with IFN-α, while 13 with PV (46%) and 15 with ET (43%) received HU, respectively. Clinical characteristics were similar between both treatment groups and no significant differences were observed. During a median follow-up period of 81 months (range, 48-168 months) 97% of the patients treated with IFN-α achieved a hematologic response [60% complete (CHR), 37% partial (PHR)] compared to 78% in HU group (56% CHR, 20% PHR; p Disclosures No relevant conflicts of interest to declare.