Positive results in Phase 2 trial of treatment of C-difficile-associate...( Princeton N.J. and Jamaica Plain Mas...)

Princeton, N.J. and Jamaica Plain, Mass., November 3, 2008 Medarex, Inc. (Nasdaq: MEDX) and The Massachusetts Biologic Laboratories (MBL) of the University of Massachusetts Medical School (UMMS) today announced that a Phase 2 trial of an anti-C. difficile antibody combination treatment in patients with C. difficile Associated Diarrhea (CDAD) successfully met its primary objective. The top-line results from the recently completed multi-center, randomized, double-blind, placebo-controlled Phase 2 trial indicated a statistically significant reduction in recurrences of CDAD when compared with placebo. In the study, 200 patients symptomatic with CDAD receiving standard of care antibiotics (metronidazole or vancomycin) were randomized to receive either intravenous placebo or intravenous administration of a combination of MDX-066 (CDA-1) and MDX-1388 (CDB-1), two fully human antibodies that neutralize C. difficile toxins A and B, respectively.

Consistent with the published literature, the recurrence rate in the placebo-treated group exceeded 20 percent for patients following successful treatment with standard of care antibiotics. In comparison with placebo, MDX-066/MDX-1388 treatment reduced recurrence rates by approximately 70 percent (p=0.0004 on the intent-to-treat population). The antibody combination treatment was generally safe and well-tolerated. Full results from this Phase 2 trial are planned to be presented at a future scientific meeting.

The incidence and mortality associated with CDAD has been increasing , with estimates of over 500,000 cases in the United States, and approximately 15,000 deaths caused or contributed by C. difficile. The emergence of a highly virulent epidemic strain that produces much higher levels of toxins A and B has also been associated with morbidity and mortality in younger, healthier, and non-hospitalized patients.

"We are delighted with these dramatic results. CDAD is a gr
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