Credit: AFIP
The US Food and Drug Administration (FDA) has expanded the approved use of ruxolitinib (Jakafi) to include treatment of patients with polycythemia vera (PV).
This is the first drug approved by the FDA for this condition.
Ruxolitinib can now be used to treat PV patients who have an inadequate response to hydroxyurea or cannot tolerate the drug.
The FDA said the approval of ruxolitinib for PV patients will help decrease splenomegaly and the need for phlebotomy.
“The approval of Jakafi for polycythemia vera underscores the importance of developing drugs matched to our increasing knowledge of the mechanisms of diseases,” said Richard Pazdur, MD, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research.
“The trial used to evaluate Jakafi confirmed clinically meaningful reductions in spleen size and the need for phlebotomies to control the disease.”
Results from that study, the phase 3 RESPONSE trial, were presented at the 2014 ASCO Annual Meeting. RESPONSE was funded by Incyte Corporation, the company developing ruxolitinib.
The trial included 222 patients who had PV for at least 24 weeks. All patients had an inadequate response to or could not tolerate hydroxyurea, had undergone a phlebotomy procedure, and exhibited an enlarged spleen.
They were randomized to receive ruxolitinib at a starting dose of 10 mg twice daily or best available therapy (BAT) as determined by the investigator on a participant-by-participant basis. The ruxolitinib dose was adjusted as needed throughout the study.
The study was designed to measure the reduced need for phlebotomy beginning at week 8 and continuing through week 32, in addition to at least a 35% reduction in spleen volume at week 32.
Twenty-one percent of ruxolitinib-treated patients met this endpoint, compared to 1% of patients who received BAT. At week 32, 77% of patients on ruxolitinib and 20% on BAT achieved hematocrit control or spleen reduction.
Ruxolitinib was generally well-tolerated, but 3.6% of patients discontinued treatment due to adverse events, compared to 1.8% of patients on BAT.
The most common events associated with ruxolitinib were anemia and thrombocytopenia. The most common non-hematologic events were headache, diarrhea, fatigue, dizziness, constipation, and shingles.
The FDA reviewed ruxolitinib’s use for PV under the agency’s priority review program because, at the time the application was submitted, the drug demonstrated the potential to be a significant improvement over available therapy. Ruxolitinib also received orphan product designation.
Ruxolitinib is currently approved in more than 60 countries for patients with myelofibrosis (MF). In 2011, the FDA approved the drug to treat patients with intermediate or high-risk MF, including primary MF, post-PV MF, and post-essential thrombocythemia MF.
