Cytoreductive therapy with interferon alfa (rIFNα) or hydroxyurea is safe and well tolerated in patients with polycythemia vera (PV) under the age of 60 years and induces annualized discontinuation rates comparable to those reported with these agents in older patients with PV, for whom cytoreductive therapy is routinely used, according to findings from a meta-analysis that were published in Blood Advances.1
Across the 14 studies included in this analysis, rIFNα discontinuation rates ranged from 4.6% to 37% over median durations of 0.4 to 6.3 years. Hydroxyurea discontinuation rates ranged from 2.6% to 17% over median durations of 0.5 to 14 years.
Although the use of cytoreductive agents, such as rIFNα and hydroxyurea, is associated with reduced thrombosis risk in PV, these agents are not routinely recommended by the European LeukemiaNet (ELN) or the National Comprehensive Cancer Network (NCCN) for patients with PV under the age of 60 years. The ELN recommends cytoreductive therapy for patients with PV who are younger than 60 years of age and have not had prior thrombotic events provided that they have strictly defined phlebotomy intolerance, symptomatic progressive splenomegaly, persistent or progressive leukocytosis, extreme thrombocytosis, persistently high cardiovascular risk, inadequate hematocrit control requiring phlebotomies, and/or persistently high symptom burden.2 The NCCN does not recommend cytoreductive therapy as initial treatment for patients with low-risk disease.3
“Unfortunately, effective and potentially life-prolonging cytoreductive therapy is often deferred in younger patients who are considered ‘low-risk’ because of their age and lack of thrombosis history,” senior study author Ghaith Abu-Zeinah, MD, an instructor in medicine at Weill Cornell Medical College and an assistant attending physician at the NewYork Presbyterian Hospital in New York, New York, and coauthors, wrote in the paper.1 “The rationale for withholding cytoreductive therapy is data-sparse and driven by theoretical concerns for toxicity and unknown benefits from early treatment. Yet, there is some evidence that early treatment is both well tolerated and potentially useful.”