LONDON - KS Biomedix plc filed for approval for the first-ever human clinical trial of sheep monoclonal antibodies. The trial of KS-6H9Chi will be carried out at the Nilai Cancer Institute in Malaysia, and will recruit 20 colon cancer patients with secondary metastases.
The patients will be assessed for safety, and imaged to determine the degree of tissue localization of KS-6H9Chi, labeled with iodine-131, over 10 days.
CEO Steven Powell told BioWorld International, "This is a medical imaging trial, showing how the compound could be used as an in vivo diagnostic. This has commercial value in its own right but is also a significant step toward the next stage of linking the antibody to an anticancer agent." Powell said it is not decided yet what this agent should be.
KS Biomedix, based in London, said that sheep monoclonal antibodies show a high affinity for tumors, and remain there longer than other types of antibodies. "There is better localization, and a longer therapeutic window," said Powell. Results of the study are due before the end of 2000.
In preclinical studies in a mouse xenograft model of colon cancer, KS-6H9Chi demonstrated high specificity for, and significant retention time within, the human colon cancer cells implanted in the mice. Of the total dose, 40 percent of the antibody localized in the tumor after one day, and the same amount was detectable in the tumor after 10 days. Localization in other tissues including lung, spleen, kidney, stomach and intestines was less than 5 percent.
The company also announced an exclusive license agreement with the University of Medicine and Dentistry of New Jersey, for a novel antigen drug target for ulcerative colitis, and a candidate murine therapeutic antibody. It plans to develop sheep monoclonal antibodies to fit the target.
"This is a novel target which has a huge value in its own right," Powell said. "With the murine antibody and our sheep antibodies we will command a very strong position in ulcerative colitis and will be able to move very quickly into development.
"Until now we have concentrated on developing our core antibody capability. We are now moving from the technology platform to development and looking for additional targets to fit our core antibody focus."