Medarex Inc. said Tuesday that it is beginning a multicenterPhase I/II trial of its MDX-11 monoclonal antibody-basedtherapeutic as an adjunct treatment for acute myeloidleukemia.

The trial will include 30 to 50 AML patients who areexperiencing relapse. The life expectancy of these patients isabout four months. All patients will be treated withconventional chemotherapeutics in conjunction with MDX-11.

AML is a rapidly spreading cancer of bone marrow and bloodcells, afflicting about 11,000 new patients annually in theUnited States. MDX-11 received orphan drug designation forAML in 1991.

MDX-11 binds to leukemia cells, activating natural serumproteins called complement that act in a cascade to attack cellsmarked by antibodies. MDX-11 is intended to preclude relapsesby destroying residual leukemia cells and their precursors.

Medarex is also conducting Phase II trials of an ex vivo bonemarrow purge for patients with AML. The marrow purge usestwo MAbs, including the one in MDX-11, said Donald Drakeman,president of the Princeton, N.J., company (NASDAQ:MEDX). Themarrow purge and the in vivo MDX-11 therapy can be usedtogether.

The company plans to file two additional investigational newdrug applications this year for therapeutics using itsantibodies.

Bi-specific antibodies link two antibody fragments, one ofwhich is a unique antibody that triggers an immune response,said Drakeman. The triggering antibody is linked to any one ofa series of targeting antibodies that bind to particular cells orviruses.

One IND will be for an HIV therapeutic to activate themonocytes and macrophages that kill the virus and infectedcells. The second will be a product to treat ovarian and breastcancers.

Medarex stock lost 63 cents to $11.50 on Tuesday. -- KarenBernstein

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