Genmab announced that Humax-CD20 binds to a unique site on CD20 target cells when compared to other known CD20 antibodies. This is a distinguishing characteristic of Humax-CD20 and may help explain why Humax-CD20 has outperformed other CD20 antibodies in a variety of pre-clinical studies. Furthermore, in a novel cancer disease model in immuno-compromised mice using sensitive bioluminescence imaging, new data show that Humax-CD20 appears to stop growth of B-cell tumours grown from a laboratory cell line far more effectively than either placebo, or a marketed treatment, rituximab.

Dr Jan van de Winkel, chief scientific officer of Genmab, presented this new pre-clinical data on Humax-CD20 today at the 45th Annual Meeting of the American Society of Hematology in San Diego, California.

"We have observed the unusually good performance of Humax-CD20 in a large number of pre-clinical tests, and have been conducting research to help explain why the antibody binds to and kills the disease target cells so effectively," said Lisa N Drakeman, PhD, CEO of Genmab.

"We are excited by the discovery that Humax-CD20 uses a unique site to attach to disease cells. We are also pleased to add to the growing body of positive pre-clinical data for this antibody."

Humax-CD20 was evaluated in a mouse model in which disseminated outgrowth of human B-cell tumour cells is followed using optical imaging. Tumours were induced by inoculating Daudi cells, a CD20-expressing human lymphoma cell line, which readily grows in immuno deficient (SCID) mice. For this model Daudi cells were transfected with luciferase which makes them bioluminescent after administration of luciferin, thus permitting detection using a sensitive camera. This technique is suitable for establishing growth curves of small tumour metastases in mice. In this model we compared the therapeutic efficacy of different CD20 antibodies, given as a single low dose in an early stage of tumour development (8 days after inoculation).