The study enrolled patients with chronic lymphocytic leukemia ( CLL ), heavily pre-treated, who did not respond to, or who were ineligible for, currently available treatment options such as Fludarabine ( Fludara ) and Alemtuzumab ( MabCampath ).

Based on an assessment from an independent endpoint review Committee, Ofatumumab ( Arzerra ) demonstrated a 58% response rate in patients resistant to Fludarabine and Alemtuzumab ( FA-ref ). In those patients who did not respond to Fludarabine and were not suitable for Alemtuzumab ( BF-ref ), Ofatumumab demonstrated a 47% response rate.

Study results showed that Ofatumumab treatment demonstrated no unexpected adverse events. Infusion reactions at the first dose were seen in 38% of patients but these diminished over the course of the treatment.

The most common grade three or four related adverse events during the treatment period were infections and neutropenia. Early death ( less than 8 weeks from treatment initiation ) occurred in four FA-ref and two BF-ref patients none of which were considered related to Ofatumumab.

Globally, 300,000 new cases of leukaemia are diagnosed each year and 222,000 patients lose their lives. Chronic lymphocytic leukemia is the most common form of leukaemia in adults in western countries, accounting for 25 percent of all leukaemias. The annual incidence rate is projected to be between