On December 4, 2014, the U. S. Food and Drug Administration approved ruxolitinib (Jakafi, Incyte Corporation) for the treatment of patients with polycythemia vera (PV) who have had an inadequate response to or are intolerant of hydroxyurea (HU).
The approval was based on demonstration of a composite endpoint of durable hematocrit control and spleen volume reduction and in achieving a relatively high rate of durable hematocrit control that obviated the need for regular phlebotomy. The multicenter, open-label, active-control trial (Protocol CINC424B2301) leading to the approval, enrolled 222 patients with PV resistant to or intolerant of HU. Patients were randomized to receive either ruxolitinib 10 mg twice daily (n=110) or best available care (n=112).
Ruxolitinib was superior to best available therapy in achieving durable hematocrit control and spleen volume reduction at week 32 (21% vs 1%, p<0.0001) and at week 48 (19% vs 1%, p<0.0001), and in achieving a relatively high rate of durable hematocrit control (week 48) (55%, 95% CI 45%-64%).
Safety through week 32 was evaluated in the 110 subjects randomized to ruxolitinib. The most common hematologic adverse reactions (incidence > 20%) were thrombocytopenia and anemia. The most common nonhematologic adverse events (incidence >10%) were headache, abdominal pain, diarrhea, dizziness, fatigue, pruritus, dyspnea and muscle spasms. Discontinuation for adverse events, regardless of causality, was observed in 4% of patients treated with ruxolitinib.
The recommended starting dose of ruxolitinib is 10 mg twice daily (5 mg twice daily for patients taking strong CYP3A4 inhibitors and for those patients with moderate-to-severe renal impairment or with hepatic impairment). Doses may be titrated based on subsequent safety and efficacy evaluations.
Full prescribing information, including clinical trial information, safety, dosing, drug-drug interactions and contraindications is available at: http://www.accessdata.fda.gov/drugsatfda_docs/label/2014/202192s008lbl.pdf
Healthcare professionals should report all serious adverse events suspected to be associated with the use of any medicine and device to FDA’s MedWatch Reporting System by completing a form online at http://www.fda.gov/medwatch/report.htm, by faxing (1-800-FDA-0178) or mailing the postage-paid address form provided online, or by telephone (1-800-FDA-1088).