Updated Dosing Guidance and Safety Information for Jakafi
The FDA updated the prescribing information for Jakafi (ruxolitinib), the first drug approved to treat myelofibrosis. The new guidelines indicate patients with baseline platelet counts between 50,000 and 100,000 should start their dosage as 5 mg tablets twice daily. Providers can then monitor patients and change the dosage if necessary.
In addition, after reviewing a supplemental new drug application and an ongoing phase 2 trial, the FDA updated the Warnings and Precautions section of the prescribing information to indicate some patients taking myelofibrosis may have progressive multifocal leukoencephalopathy (PML). If PML is suspected, patients should stop taking ruxolitinib.
Incyte Corporation, which markets the drug, said in a news release that one of the approximately 9800 patients treated with ruxolitinib in clinical trials or for commercial use have had PML.
The FDA approved ruxolitinib in November 2011 for patients with intermediate or high-risk myelofibrosis. Incyte estimates that approximately 16,000 to 18,500 people in the United States have myelofibrosis.
The approval was based on results of two, phase 3 trials that included 528 patients who received ruxolitinib, placebo, or the best available therapy. Compared with the other treatment groups, a larger percentage of patients taking ruxolitinib had more than a 35% reduction in spleen size and a 50% reduction in myelofibrosis-related symptoms.
Serious side effects associated with ruxolitinib in the studies included thrombocytopenia, anemia, fatigue, diarrhea, dyspnea, headache, dizziness, and nausea.
-Tim Casey
