First-Line Use of Ruxolitinib and Dosing Modifications in Patients With Polycythemia Vera

There are no cures available to patients with polycythemia vera (PV), who are first treated with hydroxyurea (HU); ruxolitinib is approved as a second-line therapy in both Europe and the United States for patients who are intolerant of or resistant to HU. Two abstracts being presented at the 61st American Society of Hematology Annual Meeting & Exposition in Orlando, Florida, explore the use of ruxolitinib in patients with PV.

The first abstract¹ analyzed use of ruxolitinib in newly diagnosed patients with PV. The German study Ruxo-BEAT treated 28 patients with ruxolitinib for at least 6 months. It was a multicenter, open-label, 2-arm phase 2b trial. Another 22 patients received best available therapy. There was the opportunity for crossover between the 2 arms after 6 months.

For the patients receiving ruxolitinib, the mean hematocrit level decreased from 45.9+/—5.6% to 41.0+/–5.0% after 6 months of treatment. The mean JAK2V617F allele burden decreased from 50.2+/28.4% to 44.0+/–28.5%. The percentage of patients with night sweats had decreased from 30% to 11% and the percentage with pruritus decreased from 41% to 26%.

Recruitment into this trial is ongoing.

In the second abstract,² the researchers analyzed why patients were switched from HU to ruxolitinib and described real-world dosing patterns. They conducted a retrospective medical chart review at practices in the Cardinal Health Oncology Provider Extended Network. Patients had started ruxolitinib between January 1, 2015, and December 31, 2016, and had previously been treated with HU for at least 3 months. They were at least 18 years old and were seen 2 or more times during the 6 months after starting ruxolitinib.

Overall, 99 patients were included and 99% of them were positive for the JAK2V617F mutation. More than a quarter (28%) of patients had reached a HU dose of ≥2 g/d by the time they discontinued HU. Most commonly, patients discontinued HU because of resistance (63%), followed by intolerance (17%), both resistance and intolerance (11%), and other reasons (9%).

Less than half (44%) of patients started ruxolitinib at the recommended dose of 10 mg twice daily. Within 6 months, 19 of those patients (43%) modified their dose: 13 (30%) had their dose increased, 5 (11%) had the dose decreased, 1 (2%) had the dose interrupted. After the 6 months, these patients needed fewer dose modifications.

Of those patients who discontinued ruxolitinib, 65% had no dosing changes during their treatment.

References

1. Koschmieder S, Isfort S, Wolf D, et al. Ruxolitinib shows efficacy in patients with newly-diagnosed polycythemia vera: futility analysis of the randomized Ruxo-BEAT clinical trial of the German study group of myeloproliferative neoplasms. Presented at: 61st American Society of Hematology Annual Meeting & Exposition, December 7-10, 2019; Orlando, Florida. Abstract #2944.
2. Altomare I, Nguyen A, Parasuraman S, et al. Real-world dosing patterns of ruxolitinib in patients with polycythemia vera who are resistant to or intolerant of hydroxyurea. Presented at: 61st American Society of Hematology Annual Meeting & Exposition, December 7-10, 2019; Orlando, Florida. Abstract #4192.