In July 2023, the U.S. Food and Drug Administration (FDA) licensed CYFENDUS™, a novel anthrax vaccine developed with extensive support from NIAID and federal collaborators. CYFENDUS™, also known as AV7909, is a two-dose vaccine that offers faster protection than the previously approved three-dose anthrax vaccine, BioThrax. The licensure is an important step by the U.S. Government to prepare for intentional or naturally occurring biothreats.
CYFENDUS and BioThrax were both developed by Emergent BioSolutions for post-exposure prophylaxis of disease following suspected or confirmed exposure to Bacillus anthracis. CYFENDUS is comprised of Anthrax Vaccine Adsorbed (AVA) plus a second adjuvant. Whereas BioThrax is administered in three doses over 28 days, CYFENDUS provides protection after two doses, administered over a 14-day period.
NIAID provided critical preclinical and early clinical support to advance the development of CYFENDUS. Preclinical support from NIAID and the Biomedical Advanced Research and Development Authority (BARDA) included GMP manufacturing, safety and toxicity evaluation, and animal model studies that assessed protective efficacy. The FDA’s Animal Model Rule requires that anthrax countermeasures establish efficacy in animal models as clinical efficacy trials in humans are not possible. NIAID funded the development of a new aerosol challenge model for inhalation anthrax, as well as studies using the new model to determine the vaccine’s efficacy. Following a Phase 1a trial supported by the Defense Advanced Research Projects Agency (DARPA), NIAID and BARDA funded a Phase 1b trial in healthy adults that showed the vaccine was safe and immunogenic. NIAID then funded a Phase 2 study to establish the vaccine’s immunogenicity at two doses, providing the critical data needed for advanced clinical evaluation, supported by BARDA, and ultimate FDA licensure.