In addition to controlling hematocrit and improving splenomegaly and symptoms, ruxolitinib provided durable and comprehensive hematological control, according to results of the RESPONSE study.

Investigators compared the efficacy of ruxolitinib with best available therapy in achieving target elevated hematocrit, white blood cell, and platelet levels. Although the study was not powered to assess thromboembolic events, researchers observed the following:

• There were 1.8 thromboembolic events per 100 patient-years of exposure in ruxolitinib-treated patients.
• This rate in those receiving best available therapy was 8.2/100 patient-years of exposure.