Medarex And PharmAthene Announce New Therapeutic Data for Anthrax Anti-Toxin, V...(d/or a positive ECL were used to identif...)

In this study, 94 percent (30/32) of the animals were subsequently shown to be bacteremic at the time of treatment. Twelve of the NZW rabbits were treated with an intravenous (IV) 10 mg/kg dose of Valortim, 8 were treated with a 20 mg/kg IV dose of Valortim, and 12 were treated with IV saline in the control group. Study findings showed that 100 percent (8/8) of the 20 mg/kg Valortim-treated animals survived compared to 83 percent (10/12) in the 10 mg/kg Valortim-treated group and 8 percent (1/12) in the control group.

About Valortim

Valortim (MDX-1303) is a fully human monoclonal antibody designed to protect against and treat anthrax infection, including inhalation anthrax, the most lethal form of illness in humans caused by the Bacillus anthracis bacterium. The investigational antibody is designed to target a protein component known as the anthrax protective antigen (PA) of the lethal toxin complex produced by the bacterium. The anthrax protective antigen is believed to initiate the onset of the illness by attaching to cells in the infected person, and then is believed to facilitate the entry of additional destructive toxins into the cells. Valortim is designed to target anthrax protective antigen and protect the cells from damage by the anthrax toxins.

As previously presented, Valortim has been administered intravenously and intramuscularly to healthy human volunteers in a completed Phase 1 study, was well tolerated at doses as high as 20 mg/kg (IV), and was not immunogenic. Pharmacokinetic analysis suggested that doses as low as 1 mg/kg resulted in circulating levels of antibody after a month, with a similar potency for neutralizing anthrax toxin in vitro as was seen with serum obtained from subjects who had been vaccinated with anthrax vaccine.

Preclinical
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