Contemporary Use of Interferon Therapy in the Myeloproliferative Neoplasms

Purpose of Review: The purpose of this article is to review the current evidence behind interferon therapy in patients with myeloproliferative neoplasms. Recent Findings: Preliminary analysis suggests that interferon may be non-inferior to hydroxyurea in patients with polycythemia vera and essential thrombocytosis. Responses have been observed regardless of JAK2 mutational status, but the presence of non-JAK2 somatic mutations may negatively influence response rates. Summary: Pegylated interferon has proven efficacy for patients with myeloproliferative neoplasms. Both newly diagnosed and previously treated patients with polycythemia vera and essential thrombocytosis exhibit high hematologic response rates, and some of these patients achieve molecular responses as well. Interferon therapy leads to lower rates of hematologic response in MF patients, but patients earlier on in their disease course have a better chance of responding. There are ongoing trials comparing pegylated interferon to hydroxyurea in essential thrombocytosis (ET) and polycythemia vera (PV), and early analysis suggests non-inferiority. However, longer follow-up is needed before drawing any conclusions. Future research is needed to better define characteristics of the best responders and to determine whether novel forms of interferon therapy or combination therapy with interferon can enhance efficacy and tolerability.