Data from a phase I/II study of the novel anti CD20 monoclonal antibody, of atumumab (formerly HuMax-CD20) in patients with relapsed or refractory B-cell chronic lymphocytic leukaemia (CLL) demonstrate anti-tumour responses in half of the patients treated in one of the three cohorts. The study is published in the February issue of the journal Blood. Ofatumumab is being co-developed by GlaxoSmithKline (GSK) and Genmab A/S and has not received regulatory approval in any market for any indication at this time.

"Almost all patients with CLL experience disease progression after initial therapy, and currently there are limited therapeutic options for this group," said Professor Bertrand Coiffier, Head of Haematology Department, Centre Hospitalier Universitaire de Lyon, France and lead investigator in the trial. "These early clinical data on ofatumumab are encouraging, with responses seen in half of the patients treated in the highest cohort."

Ofatumumab is a unique investigational monoclonal antibody (MAb) that targets a distinct antibody binding site (the small loop epitope) of the CD20 molecule on the cell membrane of B cells. This is a different binding site from approved antiCD20 monoclonal antibodies and it is closer to the cell membrane. The CD20 molecule is a key target in CLL therapy because it is expressed in most cancers affecting the B cell.

"CLL is a common but very serious form of leukaemia. Any hope for an effective new therapy may bring promise to those affected by the disease," said Paolo Paoletti, MD, Senior Vice President, Oncology Medicine Development Centre, GSK. "We are very excited by these data and the potential that ofatumumab has shown to date in treating patients with relapsed or refractory CLL."

CLL is the most common type of leukaemia and one of the most common malignant lymphoid diseases in the western world. Globally, leukaemia, in all of its forms, accounts for approximately 300,000 new cases each year (2.8% of all new cancer cases) and 222,000 deaths.