Medarex Inc. reported on Monday that its bone marrow purgefor cancer therapy is showing increased survival rates inpreliminary Phase II clinical results in patients with acutemyeloid leukemia.

Replenishing the bone marrow can spare patients from thetoxicity of high-dose chemotherapy. Medarex (NASDAQ:MEDX)uses monoclonal antibodies to ensure that a patient's ownmarrow can be purged of leukemia cells, then reinfused.

Presenting to the American Society of Hematology meeting inDenver, the company said patients undergoing the purgeshowed a two-year mean survival rate of 67 percent, comparedwith a 25 percent survival rate expected with conventionaltherapies without marrow transplants.

Medarex did not provide comparison survival figures fortherapies that include marrow transplants from donors, whichcarry risks of rejection and of graft-vs.-host disease.

Medarex's cleansing process involves activation of the immunesystem's complement proteins to destroy cells tagged by themonoclonals. Rabbit complement is added to the humanmarrow in the lab to kill any remaining cancer cells before themarrow is returned to the patient.

No marrow purge has been approved by the Food and DrugAdministration, said company President Donald Drakeman, whobelieves the new FDA guidelines for accelerated drug approvalshould speed up market debut for the monoclonal. "I think wecan be much more optimistic for a '93 release" of the antibody,he told BioWorld.

The Princeton, N.J., company estimates that acute myeloidleukemia is diagnosed in about 10,000 new patients each yearin the United States.

The company intends to start a multicenter Phase I/II trial ofthe same antibody as a leukemia therapy for late-stagepatients early next year, Drakeman said.

Medarex shares closed at $13, up 50 cents. -- RobertaFriedman, Ph.D.

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