According to a study presented at the 11th Annual Meeting of the Society of Hematologic Oncology (SOHO), “Resistance/intolerance to first-line hydroxyurea occurs in ~24% of patients with polycythemia vera (PV); ruxolitinib is recommended in second-line.” The study’s investigators, therefore, conducted a longitudinal analysis to examine the characteristics and outcomes of patients with PV receiving ruxolitinib after hydroxyurea.
Data from 1053 patients with PV receiving hydroxyurea ≥3 months before enrollment were included in the analysis. The patients were categorized into 2 groups: those who switched to ruxolitinib after hydroxyurea (HU-RUX, n=147) and those who continued hydroxyurea treatment (HU, n=906). Various parameters were compared between the groups at specific time points, including diagnosis, treatment duration, symptom severity, spleen size, blood parameters, and thrombotic event (TE) history.
“Patients who switched to ruxolitinib had more severe disease burden vs hydroxyurea, and demonstrated improved PV-related symptoms, spleen size reduction, and sustained blood parameter improvements,” the investigators wrote regarding the results of their study.
Patients in the HU-RUX group exhibited a longer median time from diagnosis (6.9 years) than those on HU (4.8 years). Hydroxyurea discontinuations were mainly due to ineffectiveness (36.1%), toxicity (32.0%), and progression (6.8%). In addition, HU-RUX patients had more severe disease characteristics at baseline, including higher symptom scores (27.5 vs 17.3), more palpable spleens (40.8% vs 9.3%), elevated white blood cell counts (18.1% vs 7.8%), and a higher history of TEs (27.2% vs 19.3%).
Among HU-RUX patients, 62.6% received the recommended initial ruxolitinib dose. The median ruxolitinib treatment duration was 1.9 years, with 89.1% continuing for ≥6 months. 25.9% required dose adjustments, while 84.4% remained on ruxolitinib. HU-RUX patients experienced significant improvements after 12 months in terms of lower Myeloproliferative Neoplasm Symptom Assessment Form total symptom scores (-4.4 vs -5.2) and mean spleen length (-4.9 cm vs -5.8 cm).
The investigators also found the need for phlebotomies substantially decreased in HU-RUX patients. The average number of phlebotomies decreased from 1.3-0.5 at 6 months post-index, and 74.8% no longer required phlebotomies 12 months post-index.
According to the investigators, the outcomes validate the efficacy of ruxolitinib treatment following hydroxyurea use. “Monitoring patients receiving hydroxyurea may identify those likely to benefit from switching to ruxolitinib,” they concluded.
Gers A, Grunwald M, Oh S, et al. Characteristics and Clinical Outcomes in Patients With Polycythemia Vera Receiving Ruxolitinib After Hydroxyurea: A Longitudinal Analysis From the Prospective Observational Study of Patients With Polycythemia Vera in US Clinical Practices Trial (REVEAL). Abstract MPN-574. Presented at the 11th Annual Meeting of the Society of Hematologic Oncology; September 6-9, 2023; Houston, Texas.