A real-world single-center retrospective study on efficacy and safety of pegylated interferon alpha-2a in patients with myeloproliferative neoplasm.

Abstract

e19536 Background: Pegylated forms of interferon (PEG-IFN) have a better pharmacologic profile than short-acting interferons, resulting in a more convenient less-frequent schedule of injections, less immunogenicity and possibly less toxicity. Several clinical studies of PEG-IFN-α-2a have reported promising results in patients with essential thrombocythemia (ET) and polycythemia vera (PV). Herein, we present the outcomes of MPN patients treated with PEG-IFN-α-2a seen outside of a clinical trial setting at a single center. Methods: Thirty-five MPN Patients treated with PEG-IFN-α-2a between January 2014 and October 2019 were included this retrospective analyses. Therapeutic responses for ET and PV were calculated by the revised ELN/IWG-MRT criteria. Responses in myelofibrosis (MF) were calculated by both EUMNET and ELN/IWG-MRT criteria. Best responses over all cycles of treatment were assessed. Molecular data was limited to JAK V617F. Results: Twenty patients with ET, 13 with PV and two with MF were enrolled in this study. The median age at diagnosis was 47 years (range; 21-83 years). JAK2 V617F mutation was detected in 16 patients (45.7%). Overall, the majority of patients (62.9%) had received at least one prior cytoreductive therapy for underlying disease. Median starting dose of PEG-IFN-α-2a was 90 mcg/week via self injection (range: 45-135 mcg/w). Treatment duration was pursued for a median duration of 21.4 months (range: 1.2-109.8). In the PV/ET group 33 patients were evaluated and overall best response rate was 87.8% (CR in 15 pts and PR in 14 pts). In the MF group (n = 2); a PR was seen in one patient and CR in one patient. No vascular events occurred within the cohort while on therapy. Of the eight patients receiving at least phelebotomy per month, all patients became phelobotomy independent with therapy. Of the 20 ET patients, 12 patients (60%) had platelet normalization (< 450 x 109/L). Among all patients, fatigue (31.4%), muscle pain (20%) and depression (8.6%) were the most common adverse events (AEs). Any grade of hematological AEs was not seen with PEG-IFN-α-2a. Eleven patients discontinued therapy secondary to: treatment associated severe AEs in 8 patients, lack of response in two patients and pregnancy in one patient. No death was reported during the analyses period. Conclusions: Our results suggest that PEG-IFN-α-2a remains a viable treatment option especially for younger patients who want to avoid prolonged cytotoxic therapy.