Ruxolitinib is an effective long-term treatment option for patients with polycythemia resistant or intolerant to hydroxyurea, according to a study presented at the 2016 European Hematology Association Congress.1

The phase 3 RESPONSE trial (Study of Efficacy and Safety in Polycythemia Vera Subjects Who Are Resistant to or Intolerant of Hydroxyurea: JAK Inhibitor INC424 (INCB018424) Tablets Versus Best Available Care; Identifier: NCT01243944) is evaluating the efficacy and safety of ruxolitinib vs best available care in hydroxyurea-resistant or intolerant patients with polcythemia vera.

After 80 weeks of follow-up, results showed that no patients remained on best available therapy and 87.5% had crossed over to ruxolitinib, most at or soon after week 32.

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The investigators found that 22.7% of patients receiving ruxolitinib had achieved a primary response by week 32 compared with only 0.9% of those randomly assigned to best available therapy; hematocrit control was 60.0% vs 18.8%, respectively.

Results further demonstrated that 92% of ruxolitinib-treated patients maintained their primary response and 89% maintained their hematocrit response for 80 weeks or longer. Of the 44 who achieved a spleen response at week 32, 43 were maintained until week 80.

In addition, 23.6% of patients initially assigned to receive ruxolitinib achieved a complete hematologic remission at week 32, with 69% maintaining complete hematologic remission for 80 weeks or more.

In terms of safety, researchers observed new or worsening anemia, lymphopenia, and thrombocytopenia, which were primarily grade 1 to 2, in ruxolitnib-treated patients.


1. Vannucchi AM, Griesshammer M, Masszi T, et al. Ruxolitinib versus best available therapy in patients with polycythemia vera: 80-week follow-up from the RESPONSE trial. Poster presented at: European Hematology Association 21st Congress; June 9-12, 2016; Copenhagen, Denmark.