By IDSE News Staff
The FDA approved anthrax vaccine adsorbed, adjuvanted (Cyfendus, Emergent) for post-exposure prophylaxis following suspected or confirmed exposure to Bacillus anthracis in people 18 through 65 years of age when administered with recommended antibacterial drugs.
The efficacy of the anthrax vaccine for post-exposure prophylaxis is based solely on studies in animal models of inhalational anthrax. However, Emergent has been delivering the vaccine to the Department of Health and Human Services since 2019, under pre–emergency use authorization status. Emergent said it would and work with the government to transition to post-approval procurement.
The vaccine consists of anthrax vaccine adsorbed and an additional adjuvant. It has been demonstrated that two doses administered over 14 days elicit protective levels of immune response, which can be especially important in response to a large-scale public health emergency involving anthrax. In December 2018, the vaccine was the subject of a pre–emergency use authorization package submitted to the FDA. The following year, the government began procuring this product for national preparedness efforts.
In addition to Cyfendus, Emergent’s anthrax franchise includes the Biothrax vaccine, which will continue to serve a critical purpose, as well as two treatments: Anthrasil anthrax immune globulin intravenous (human), a polyclonal antibody therapeutic, and raxibacumab, a monoclonal antibody therapeutic.
The FDA approval of the Cyfendus vaccine is based on data from a series of studies supported by the government and conducted by Emergent, including:
- a pivotal phase 3 clinical study that evaluated the lot consistency, immunogenicity and safety of the vaccine following a two-dose schedule administered intramuscularly in healthy adults;
- a phase 2 study that evaluated non-interference between the vaccine and antibacterial drugs approved for post-exposure prophylaxis of anthrax disease; and
- nonclinical studies that assessed protective efficacy of the vaccine against lethal challenge with anthrax spores and helped identify neutralizing antibody levels associated with protection against disease.
“Cyfendus vaccine is a component of the U.S. government’s preparedness efforts against anthrax, which remains a high-priority national security threat due to its ability to be easily disseminated, lethality, and potential for major public health impact,” said Paul Williams, Emergent’s senior vice president, products business. “The approval of the Cyfendus vaccine demonstrates what effective public-private partnerships can achieve for national security. Emergent will continue to work closely with the government to transition this product to post-approval procurement while ensuring an uninterrupted supply of this important vaccine.”
The most common adverse reactions reported were tenderness, pain, warmth, itching, swelling, redness, bruising, arm motion limitations, muscle aches, tiredness, headache and fever. The full prescribing information for the vaccine can be found here.
