Phase 1 PK Study of XOMA 3AB

This is a phase I, single-center, placebo-controlled, double-blinded, dose escalation study of anti-botulinum toxin monoclonal antibodies in healthy adult volunteers. Volunteers will be hospitalized in the Johns Hopkins Phase 1 unit during the infusion and until after the 24-hour blood draw. Three escalating dose cohorts of a combination of three anti-botulinum monoclonal antibodies will be evaluated. Each cohort will consist of eight volunteers in which they will receive a single intravenous infusion of active drug or placebo. Placebo will be normal saline. Volunteers will be followed for safety for up to 120 days after infusion depending on dose cohort.