Pegylated interferon alfa-2a for polycythemia vera or essential thrombocythemia resistant or intolerant to hydroxyurea.
Prior studies have reported high response rates with recombinant interferon-α (rIFN-α) therapy in patients with essential thrombocythemia (ET) and polycythemia vera (PV). To further define the role of rIFN-α, we investigated the outcomes of pegylated-rIFN-α2a (PEG) therapy in ET and PV patients previously treated with hydroxyurea (HU). The Myeloproliferative Disorders Research Consortium (MPD-RC)-111 study was an investigator-initiated, international, multicenter, phase 2 trial evaluating the ability of PEG therapy to induce complete (CR) and partial (PR) hematologic responses in patients with high-risk ET or PV who were either refractory or intolerant to HU. The study included 65 patients with ET and 50 patients with PV. The overall response rates (ORRs; CR/PR) at 12 months were 69.2% (43.1% and 26.2%) in ET patients and 60% (22% and 38%) in PV patients. CR rates were higher in CALR-mutated ET patients (56.5% vs 28.0%; P = .01), compared with those in subjects lacking a CALR mutation. The median absolute reduction in JAK2V617F variant allele fraction was -6% (range, -84% to 47%) in patients achieving a CR vs +4% (range, -18% to 56%) in patients with PR or nonresponse (NR). Therapy was associated with a significant rate of adverse events (AEs); most were manageable, and PEG discontinuation related to AEs occurred in only 13.9% of subjects. We conclude that PEG is an effective therapy for patients with ET or PV who were previously refractory and/or intolerant of HU. This trial was registered at www.clinicaltrials.gov as #NCT01259856.
Yacoub, A; Mascarenhas, J; Kosiorek, H; Prchal, JT; Berenzon, D; Baer, MR; Ritchie, E; Silver, RT; Kessler, C; Winton, E; Finazzi, MC; Rambaldi, A; Vannucchi, AM; Leibowitz, D; Rondelli, D; Arcasoy, MO; Catchatourian, R; Vadakara, J; Rosti, V; Hexner, E; Kremyanskaya, M; Sandy, L; Tripodi, J; Najfeld, V; Farnoud, N; Papaemmanuil, E; Salama, M; Singer-Weinberg, R; Rampal, R; Goldberg, JD; Barbui, T; Mesa, R; Dueck, AC; Hoffman, R
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