Ofatumumab and bendamustine in previously treated chronic lymphocytic leukemia and small lymphocytic lymphoma.

Despite initial responses > 90% with fludarabine and rituximab-based regimens, patients with chronic lymphocytic leukemia (CLL) invariably relapse and require further treatment. Ofatumumab and bendamustine have each shown efficacy in relapsed/refractory CLL with overall response rates (ORRs) of 58% and 76%, respectively. Given excellent data with bendamustine and rituximab in relapsed/refractory CLL/small lymphocytic lymphoma (SLL), this phase II study evaluated the combination of ofatumumab and bendamustine in previously treated patients. Patients received ofatumumab 300 mg intravenously (IV) day - 7, followed by ofatumumab 1000 mg IV day 1 and bendamustine 70 mg/m(2) days 1 and 2 of each 28-day cycle. Patients received 4-6 cycles depending on number of prior therapies, as long as well-tolerated or until progression. Of 10 patients enrolled, the ORR was 40% and complete response rate was 20%. The median progression-free and overall survivals were 8.1 months and 16.2 months. Three patients developed Richter transformation. The study was closed early due to unexpected adverse events including infusion-related reactions, infection and neurotoxicity.