First FDA approval without trials
18.12.2012 - GSK’s monoclonal antibody against anthrax is the first to get FDA approval without having been tested for efficacy in humans.
This antibody is a very special one: fast track designation, priority review, orphan drug designation – and the first monoclonal antibody approved under the FDA’s Animal Efficacy Rule: On 14 December, the U.S. Food and Drug Administration (FDA) approved GlaxoSmithKline’s (GSK) raxibacumab injections as a treatment against inhalational anthrax. „In addition to antibiotics, raxibacumab will be a useful treatment to have available should an anthrax bioterrorism event occur,“ said the FDA official Edward Cox. The decision comes as no surprise, as GSK announced that the FDA’s Anti-Infective Drugs Advisory Committee voted 16 to 1 in support of the clinical benefit of raxibacumab – with one abstention on 2 November. The antibody was discovered in a joint venture between Cambridge Antibody Technology and Human Genome Sciences with Cambridge Antibody Technology discovering the antibody to Human Genome Sciences' target. In July 2012 HGS was purchased by GSK.
Inhalational anthrax is a form of the infectious disease caused by breathing in the spores of the bacterium Bacillus anthracis. Raxibacumab neutralizes toxins produced by the bacterium that can cause massive and irreversible tissue injury and death. Raxibacumab has additionally been approved to prevent inhalational anthrax when alternative therapies are not available or not appropriate. Its efficacy has been shown so far in rabbits and monkeys. „Sixty-four percent of animals in the monkey study and 44 percent of animals in one rabbit study receiving the 40 milligrams per kilogram dose of raxibacumab survived exposure to anthrax, compared with none in the placebo groups,“ said GSK in a press release. Trials in humans are not possible due the nature of the disease: Inhalational anthrax is as rare as it is lethal. However, at least the safety of raxibacumab could be demonstrated in 326 healthy human volunteers.