FDA Approves Ibrutinib Plus Ritixumab for CLL and SLL Treatment

FDA Approves Ibrutinib Plus Ritixumab for CLL and SLL Treatment

The FDA approved ibrutinib (Imbruvica) plus rituximab (Rituxan) as a frontline therapy for adults with chronic lymphocytic leukemia (CLL) or small lymphocytic leukemia (SLL).

The approval was based on findings from the randomized, multi-center, open-label actively controlled E1912 trial (NCT02048813) trial, where the 2-drug combination was compared to fludarabine, cyclophosphamide, and rixutimab (a regimen known as FCR) in 529 patients 70 years or younger with previously untreated CLL or SLL that required systemic therapy.

Results showed a statistically significant improvement in progression-free survival (PFS) for patients on the experimental arm (HR 0.34; 95% CI, 0.22-0.52; P < .0001). Average PFS was not reached in either arm after a median follow-up of 37 months.

The FDA reviewed the findings through Project Orbis, which allows concurrent submission and review of cancer-treating drugs among international partners. “For this application, a modified Project Orbis was undertaken because of the timing of submission to other regulatory agencies. Nevertheless, the FDA is collaborating with the Australian Therapeutic Goods Administration, Health Canada, and Swissmedic as they review the application,” the FDA said in a statement.

Recommended dosing is 420 mg of ibrutinib taken orally (with water) once a day, with rituximab initiated in cycle 2 at 50 mg/m² on day 1; 325 mg/m² on day 2; and 500 mg/m² on day 1 and 5 subsequent cycles, for 6 total cycles.

The most common adverse events, which occurred in 30% or more of patients were thrombocytopenia, diarrhea, fatigue, musculoskeletal pain, neutropenia, rash, anemia, bruising, and nausea.