Abstract
ALXN4100, a fully human antibody that binds to the protective antigen of anthrax toxin, was generated from a Fab isolated from a phage display library and was analyzed for its pharmacokinetic properties in rabbits and then used to protect rabbits from challenge with a lethal aerosol dose of Bacillus anthracis spores (≈322X LD50). All rabbits receiving 15 or 40 mg/kg of antibody 24 hours before challenge survived; survival of rabbits receiving 4 mg/kg either subcutaneously or intravenously was 80 or 90%, respectively. Susceptibility to anthrax disease appeared to be correlated with serum antibody concentration. This study indicates that ALXN4100 has the potential to be useful for prophylaxis of anthrax disease in humans.