April 4th, 2005
Eradication of Tumors in Various Mouse Models by Micromet's Novel Class of BiTE™ Drugs
Results from a Novel BiTE™ Molecule Targeting the Ep-CAM Antigen Published in Cancer Research
April 4, 2005, Munich, Germany -- Micromet AG reports results from studies on a novel representative of the Company¡¦s proprietary class of bispecific antibody derivatives called BiTE™. The new BiTEä molecule is targeting the Ep-CAM antigen, which is overexpressed with high frequency in the majority of human cancers.
The data published in Cancer Research demonstrate that the a-Ep-CAM BiTE™ can effectively prevent subcutaneous tumor outgrowth in mice with i.v. doses as low as 100 nanogram per mouse and day. Moreover, 5 daily doses of 10 microgram per mouse were sufficient to completely eradicate established tumors in all animals tested. Both experiments used tumor cells derived from a human colon carcinoma cell line. In order to assess the anti-tumor efficacy of the BiTE™ molecule in a more physiologic model also metastatic tumor tissue from ovarian cancer patients was tested in mice. Resulting tumors were substantially reduced by the a-Ep-CAM BiTE™ and, in some cases, eliminated. No help from additional human T cells or by co-stimulatory agents was required. Obviously, tumor destruction by the BiTE™ solely relied on reactivated human T cells that were carried along in patient samples. Such tumor-resident T cells are frequently found in tumor tissues but typically are in an inactive state.
"We are very excited by the high potency of an Ep-CAM-specific BiTE™ against established tumors in animals, which mirrors the enormous potency of BiTEs™ seen in cell culture experiments. The eradication of real metastatic tissue from cancer patients was however unexpected," Patrick Baeuerle, CSO of Micromet comments. "To our knowledge, BiTEs™ constitute the only class of bispecific antibodies that can redirect T cells against tumor cells under the very challenging conditions found in tumor tissue, which is a low number of mostly inactive T cells, and low drug concentration." |
