Ruxolitinib has been approved for the treatment of polycythemia vera in patients who have an inadequate response to hydroxyurea or are unable to tolerate that drug.
The Food and Drug Administration approved the drug, a Janus-associated kinase (JAK) inhibitor marketed as Jakafi, on Dec. 4. Ruxolitinib received a priority, expedited review at the agency.
“The approval of Jakafi for polycythemia vera underscores the importance of developing drugs matched to our increasing knowledge of the mechanisms of diseases,” said Dr. Richard Pazdur, director of the Office of Hematology and Oncology Products in the FDA’s Center for Drug Evaluation and Research, in a statement.
Ruxolitinib “represents an important advance for patients with uncontrolled PV,” said Dr. Srdan Verstovsek, a professor in the leukemia department at the University of Texas MD Anderson Cancer Center, Houston, in a statement issued by ruxolitinib maker Incyte Corp. “For the first time, we are able to provide these patients a treatment that has been shown to provide effective and consistent control of their blood counts and reduce spleen volume.”
Polycythemia vera, a chronic disease, causes a hyperproliferation of red blood cells. Patients may also experience an increase in white blood cells and platelets, and splenomegaly, and are at higher risk for heart attack and stroke.
“The trial used to evaluate Jakafi confirmed clinically meaningful reductions in spleen size and the need for phlebotomies to control the disease,” said Dr. Pazdur.
Dr. Richard Pazdur
Ruxolitinib was first approved in 2011 for myelofibrosis, including primary myelofibrosis, post–polycythemia vera myelofibrosis, and post–essential thrombocythemia myelofibrosis.
The new indication is for polycythemia vera patients who do not respond to or cannot tolerate hydroxyurea.
The drug’s safety and effectiveness were evaluated in a study of 222 patients who received either ruxolitinib or the best available therapy, and who had the disease for at least 24 weeks, had an inadequate response to or could not tolerate hydroxyurea, had undergone a phlebotomy procedure and exhibited an enlarged spleen.
Of patients receiving ruxolitinib, 21% experienced a reduction in the need for a phlebotomy and a reduction in spleen volume by the end of the 32-week study, compared with 1% of participants who received best available therapy.
The most common side effects were anemia and thrombocytopenia, dizziness, constipation, and shingles.
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