Ruxolitinib Well Tolerated in Untreated Patients With Polycythemia Vera

The results of the futility analysis also suggest the therapy leads to significant clinical benefits.

A futility analysis shows ruxolitinib (Jakafi) is well tolerated and reduces the need for phlebotomy in previously untreated patients with polycythemia vera (PV).

The findings were part of a phase 2b trial comparing ruxolitinib to best available therapy in high-risk patients with PV or essential thrombocythemia. The results were published in Annals of Hematology.

This study’s investigators noted that more than 85% of people with PV report a decreased quality of life due to symptoms such as fatigue, insomnia, pruritus/itching, and night sweats, among other symptoms.

Aspirin and phlebotomies aimed at reducing hematocrit below 45% are recommended for all patients, and the authors said high-risk patients—those over the age of 60 with a history of thrombosis or thromboembolism—are often treated with cytoreductive therapy with hydroxyurea or ropeginterferon-alpha (Besremi).

Ruxolitinib is a Janus kinase (JAK) inhibitor that has been previously studied in patients with PV who were resistant to or intolerant of hydroxyurea. That research suggests ruxolitinib outperforms best available therapies in terms of reducing hematocrit and the risk of thromboembolic events.

“Nevertheless, whether [ruxolitinib] treatment is also safe and effective in patients with untreated PV is currently unknown,” the authors wrote.

As part of a prespecified futility analysis in the multicenter, open-label, 2-arm RuxoBEAT trial, 28 previously untreated patients with PV were randomly assigned to receive ruxolitinib to see whether the therapy was tolerated and led to a clinical benefit. At 6 months, the investigators said patients reported several clinical benefits. Median hematocrit dropped from 46% to 41%, while the number of phlebotomies required for patients dropped from a median of 4 per year to 0. Patients also experienced improvement in their pruritus and night sweats, and JAK2V617F allele burden decreased.

Adverse events (AEs) were common, but all were grades 1 to 3. Twenty-four patients experienced at least 1 AE, and 11 patients experienced a grade 3 AE. The most common were general disorders and administration-site conditions, skin and subcutaneous tissue disorders, and nervous system disorders, athough all of those cases were either grade 1 or 2. No patient stopped taking the ruxolitinib because of AEs.

“[Ruxolitinib] treatment was well accepted by patients, as indicated by the lack of dropouts in the first 6 months of treatment among the patients analyzed so far,” the authors noted, adding that there were no new safety signals reported.

They said the specific benefits the patients noted could lead to important improvements in their cases.

“Sustained control of hematocrit levels is of major importance in PV patients, in order to decrease cardiovascular mortality (death from cardiovascular reasons or major thrombotic events),” they wrote. They said this improvement was seen without phlebotomy support, a fact that may have important quality of life effects on patients.

The investigators said their study has limitations, most notably the short time frame, which did not make it possible to see whether the therapy reduced the risk of thromboembolism.

Depending on the long-term results of the study, the authors said these data may indicate an opportunity to revise treatment strategies for PV. For now, however, they said the early analysis suggests the drug is well tolerated and warrants continued study.


Koschmieder S, Isfort S, Wolf D, et al. Efficacy and safety of ruxolitinib in patients with newly-diagnosed polycythemia vera: futility analysis of the RuxoBEAT clinical trial of the GSG-MPN study group. Ann Hematol. 2023;102(2):349-358. doi:10.1007/s00277-022-05080-7

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