The Safety and Efficacy of Ruxolitinib in Polycythemia Vera
Srdan Verstovsek, MD, PhD
Verstovek: Ruxolitinib has been studied so far in two large randomized studies in patients that are intolerant or resistant to hydroxyurea. The goal of the therapy in one of the studies to control the hematocrit and the spleen; these studies are called a response study. Primary endpoints were reduction in the spleen by 35% which is about half of the patient and to eliminate a need for phlebotomy by controlling hematocrit for about 45%. The other study is called Response to Study where patients without a big spleen were enrolled and the control of the hematocrit was the primary goal. Now we know that in the majority of the people the ruxolitinib is effective and not only controlling the red blood cells but white cell platelets and the symptoms. The goal of the study was not to look at the thromboembolic events, but now we have a longer term fall out for our response study and we know that over time based on safety analysis it appears that there is quite a difference in a number of thromboembolic events between the two arms. That is, there is hardly any event - thromboembolic event - on a ruxolitinib arm and there are quite a few on a best variable therapy arm. In the longer term fall out is quite important to document this properly. There is no real evidence of any effect of ruxolitinib on a classification to mild fibrosis or acute mild leukemia.
Srdan Verstovsek, MD, PhD of the MD Anderson Cancer Center in Houston, Texas describes the RESPONSE Study showing the efficacy of ruxolitinib in patients with polycythemia vera refractory to hydroxyurea.