Ibrutinib Plus Rituximab Demonstrate Efficacy in Phase 2 Trial of MCL

Preetesh Jain, MD, PhD, clinical fellow in medical oncology at The University of Texas MD Anderson Cancer Center, discusses the efficacy and predictors of response with ibrutinib (Imbruvica) and rituximab (Rituxan) in combination as treatment of patients with previously untreated mantle cell lymphoma (MCL).

In a phase 2 clinical trial, the response rate with the combination was excellent for these patients according to Jain. About 96% of patients responded to therapy, and in the intent-to-treat population, 90% responded. The complete response rate was in the range of 60% to 66%. He says these findings are significant because these patients were older, with a median age of 71 years, had many comorbidities, and were transplant ineligible; these were excellent responses without chemotherapy, says Jain.

Patients who responded better to the combination had low Ki-67, less than 30%, but when comparing the progression-free survival and overall survival, there were no significant differences between these patients. Jain says the study was limited by the number of patients and because the patients chosen had low-risk disease. However, these data showed patients with low KI67 had better responses than those with Ki67 over 30%, up to 50%.