Hematology Xagena

High response rates with Arzerra in patients with Fludarabine- and Alemtuzumab-refractory chronic lymphocytic leukemia

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% of all leukaemias. The annual incidence rate is projected to be between less than 1 and 5.5 per 100,000 people. However, this figure is much higher in those over 70 years of age with an annual incidence rate of 50 cases per 100,000. The specific patient population that Ofatumumab is being investigated for are CLL patients who have progressed following treatment with multiple therapies; this is a small, difficult-to-treat patient population.

Ofatumumab ( HuMax-CD20 ) is a fully human-derived, investigational monoclonal antibody (MAb). Ofatumumab binds to a specific part of the CD20 protein on the surface of B cells, known as the small loop epitope, which recruits components of the body’s immune system to attack and destroy those cells. The Ofatumumab binding site on CD20 differs from the binding site of other currently approved CD20 MAbs, such as Rituximab.

Ofatumumab is being developed to treat chronic lymphocytic leukemia, follicular lymphoma, diffuse large B cell lymphoma, Waldenstrom’s macroglobulinemia, rheumatoid arthritis and relapsing-remitting multiple sclerosis. ( Xagena )

Source: 14th Congress of European Hematology Meeting, 2009