Genmab A/S and GlaxoSmithKline announced positive top-line results from an interim analysis of the phase III pivotal study evaluating ofatumumab (HuMax-CD20) to treat two groups of chronic lymphocytic leukaemia (CLL) patients with high unmet medical need. At the interim analysis, the study met the primary endpoint in both populations and the results from the secondary endpoints also support the primary endpoint.

The activity of ofatumumab was evaluated in 154 patients in this interim analysis of whom 138 patients with refractory CLL were evaluable. About half of the patients (59) in the study were refractory to both fludarabine and alemtuzumab. The analysis also included a second group (79) who were refractory to fludarabine and considered inappropriate candidates for alemtuzumab due to bulky tumour in their lymph nodes. An objective response rate of 51% (p<0.0001) consisting of 30 partial responses (PR) was achieved in the group of patients refractory to fludarabine and alemtuzumab. In the fludarabine refractory, alemtuzumab inappropriate patient group, an objective response rate of 44% (p<0.0001) was achieved, including 1 complete response (CR), and 34 PR. Achievement of the reported objective response rates are based on evaluations by an independent committee and are subject to review and confirmation by the regulatory authorities.

Ofatumumab was generally well tolerated by CLL patients in the study. The most frequently reported adverse events (those that occurred at a greater than 15% frequency) were: pyrexia, diarrhoea, fatigue, cough, neutropenia, anaemia and pneumonia. There were no unexpected safety findings. None of the 14 patients tested for human anti-human antibodies (HAHA) demonstrated their presence at 12 months.

A pre-BLA (Biologics License Application) meeting has been requested with the FDA during which these data will be discussed with the potential of a 2008 BLA filing. There is also the potential to submit to the EU regulatory authorities in this time frame. The full data will be submitted for presentation to an academic meeting in due course.

"We are thrilled to report a positive outcome for the CLL patients in this trial," said Lisa N. Drakeman, Ph.D., chief executive officer of Genmab. "This also represents a significant achievement for Genmab as we now move toward filing of the first marketing applications for a Genmab antibody and we look forward to working with GSK on the submissions."

"These very encouraging results suggest that ofatumumab has the potential to provide benefits to CLL patients with very refractory disease and limited treatment options," said Kathy Rouan, vice president and medicine development leader at GSK. "GSK and Genmab are collaborating on a comprehensive development programme for CLL as well as non-Hodgkin's lymphoma (NHL), which we hope will make a significant contribution to the management of these haematologic malignancies for both patients and their physicians."
Ofatumumab is an investigational new generation fully human monoclonal antibody that uniquely targets the small loop epitope (specific antibody binding site) of the CD20 molecule on B cells. Ofatumumab is being developed to treat chronic lymphocytic leukaemia, follicular non-Hodgkin's lymphoma, diffuse large B-cell lymphoma, rheumatoid arthritis and relapsing remitting Multiple Sclerosis under a co-development and commercialization agreement between Genmab and GlaxoSmithKline. It is not yet approved in any country.