ARTICLE | Clinical News

Raxibacumab regulatory update

November 23, 2009 8:00 AM UTC

Human Genome Sciences said it received a complete response letter from FDA for a BLA for raxibacumab to treat inhalation anthrax. Human Genome said the agency requested additional information to complete the review. The company did not disclose what information the agency is seeking but did say that "in certain respects, the Complete Response Letter appears to be inconsistent with the FDA's published final rule governing the development of new drugs when human efficacy studies are not ethical or feasible."

In October, FDA's Anti-Infective Drugs Advisory Committee supported the overall efficacy of raxibacumab but recommended that additional studies be requested (see BioCentury, Nov. 2). Specifically, the panel voted 16-7, with one abstention, that evidence should be requested to determine whether adding ABthrax to an antimicrobial makes a contribution to efficacy over the antimicrobial alone. A panel member pointed out, however, that the Animal Rule does not require that additional benefit be shown above that provided by existing therapies. Additionally, at the start of the meeting, FDA instructed the panel to disregard pharmacokinetic data in the BLA intended to support the proposed dose of 40 mg/kg for humans. The agency said that inspections of the company's facilities identified undisclosed issues related to the sensitivity of assays used in PK studies, which raised concerns about the reliability of the data. ...