Study of the Clinical Effectiveness of a Human Monoclonal Antibody to C. Difficile Toxin A and Toxin B in Patients With Clostridium Difficile Associated Disease

Patients with Clostridium difficile associated disease who fulfill the eligibility criteria will be approached to participate. All study patients must receive standard of care treatment for Clostridium difficile associated disease. Enrolled patients will be randomized to receive a single intravenous solution of a human monoclonal antibody (huMab) to C. difficile toxin A (GS-CDA1) combined with a human monoclonal antibody to C. difficile toxin B (MDX-1388) or 0.9% sodium chloride as placebo in a 1:1 treatment allocation. Patients will be evaluated for safety and clinical outcomes through day 84 +/- 10 days. Occurrence of adverse events, use of concomitant medications, and stool output will be assessed at scheduled phone contacts and study visits. Some patients enrolled will have a subsequent visit on day 168 ± 14 days.