Medarex Inc.'s MDX-210 bispecific antibody-based therapeutictriggered an immune response in a Phase I/II trial of eightpatients with breast or ovarian cancer.

Specifically, MDX-210 coated monocytes with antibodies and infive patients increased levels of plasma tumor necrosis factoralpha (TNFa*).

Monocytes release cytokines such as TNFa when they arefighting cancer cells. In addition, one patient experienced 90percent and 40 percent reductions, respectively, in twoseparate lymph node metastases. The trial is to enroll a total of30 to 40 patients.

The company presented the study results on Thursday in LakeTahoe, Calif., at a conference sponsored by the National CancerInstitute titled "Chemoprevention of Breast Cancer: SurrogateEndpoints and Agents in Short-Term Clinical Trials."

MDX-210 consists of fragments of two monoclonal antibodieslinked together: a trigger antibody that binds to a key receptoron immune cells such as macrophages, monocytes and activatedneutrophils; and a targeting antibody that binds to the HER-2receptor that is often overexpressed on the surface of certaincancer cells, including breast and ovarian cancer cells.

Donald Drakeman, Medarex's president and chief executiveofficer, explained that monocytes can only kill cancer cellswhen specific receptors are triggered. The company's patentedTrigger antibody binds to the receptor on the macrophage andto the target cell at the same time, thus triggering the receptor.

Medarex (NASDAQ:MEDX) of Princeton, N.J., has severalbispecific antibodies in development. They all contain the sametrigger antibody and different targeting antibodies that act tokill whatever they bind to.

A compound against acute myeloid leukemia is in Phase I/IItrials and a compound targeting HIV is expected to enterclinicals in the next few months. Two bispecific compounds, onetargeting both melanoma and glioma and another targetingneuroblastoma, are in preclinicals at the Institut Curie in Paris.

Genentech Inc. and Chiron Corp. are also developing monoclonalantibodies targeted to the HER-2 protein. Genentech's productis in Phase II and Chiron's bispecific antibody, acquired whenChiron bought Cetus, is nearing clinical trials.

Medarex's stock closed unchanged on Thursday at $6.38 ashare.

-- Brenda Sandburg News Editor

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