[Novel treatment strategies for polycythemia vera: focus on ropeginterferon alfa-2b]

The current main treatment goal of polycythemia vera (PV) is preventing thromboembolic and hemorrhagic complications. However, these therapeutic strategies cannot delay progression of PV. Therefore, there is an unmet need for next-generation therapeutic strategies to slow disease progression and improve survival in patients with PV. One of the most promising agents for modifying the disease course of myeloproliferative neoplasms is interferon alpha, which has been used to treat PV since the 1980s. Notably, it achieved cytogenetic or molecular responses in some patients. However, conventional interferon was not widely used due to its high incidence of adverse events and poor tolerance. Ropeginterferon alfa-2b (ropeg) is a unique, site-selective polyethylene glycol-conjugated form of recombinant interferon alpha. A phase 1/2 study of ropeg for PV patients showed low toxicity and improved tolerability, along with significant molecular response. A phase 3 randomized study (PROUD-PV/CONTINUATION-PV) revealed that treatment with ropeg continuously decreased the JAK2V617F allele burden compared to hydroxyurea and improved event-free survival (with events defined as thromboembolic events, disease progression, or death). A phase 2 study in Japanese patients with PV further confirmed the efficacy of ropeg.