The Food and Drug Administration has expanded the indication for ibrutinib (Imbruvica) to allow its combination with rituximab for frontline treatment of chronic lymphocytic leukemia (CLL) or small lymphocytic lymphoma (SLL) in adults.
The approval, announced April 21, was based on findings from the randomized, controlled, open-label, phase 3 E1912 trial of 529 patients, which demonstrated significantly improved progression-free survival (PFS) among those who received ibrutinib plus rituximab, compared with those who received fludarabine, cyclophosphamide, and rituximab (FCR) (87% vs. 75%; hazard ratio, 0.34). Median PFS was not reached in either arm after a median follow-up of 37 months.
E1912 was the first study to show superiority of a chemotherapy-free regimen over FCR chemoimmunotherapy, considered the gold standard for newly diagnosed CLL and SLL for the past 2 decades.
The recommended dosage for the newly approved combination is a once-daily 420-mg dose of ibrutinib taken with a glass of water, with rituximab initiation in the second cycle at doses of 50 mg/m2 on day 1, 325 mg/m2 on day 2, and 500 mg/m2 on days 1-5 of subsequent cycles for a total of six cycles.
sworcester@mdedge.com