MHRP and collaborators recently launched a Phase 1 trial that will evaluate safety, tolerability, and immunogenicity of varying doses of the Army’s novel ALFQ adjuvant in a candidate HIV vaccine to optimize adjuvant dosage.
The new trial, RV575, is a randomized double-blind study that will enroll a total of 60 healthy adult participants at the Walter Reed Army Institute of Research Clinical Trials Center in Silver Spring, MD. Three arms of 20 participants will receive identical doses of the candidate vaccine antigen formulated with a different dose of ALFQ adjuvant, either 50, 100 or 200 micrograms. The 100 and 200 micrograms doses have been tested in previous clinical trials and found to be strongly immunogenic with favorable safety profiles. The hypothesis is that the 50 microgram dose of ALFQ will be equally immunogenic but demonstrate better safety profile compared to the 100 and 200 microgram doses. ALFQ adjuvant dose optimization thus has the potential to limit adverse events associated with vaccination and improve efficiency and cost effectiveness of vaccine administration.
Adjuvants are vaccine components that help activate the immune system and improve immune responses. The ALF family of adjuvants was developed by MHRP scientists at WRAIR, and preclinical as well as clinical studies have shown them to be potent adjuvants. One promising formulation, ALFQ, is being studied in combination with several vaccines, including HIV, COVID-19 and malaria, to boost immune responses.
The candidate vaccine antigen combines two investigational products: A244 and B.63521. A244 is a protein vaccine provided by Duke University and is similar to the "E" component of the AIDSVAX®B/E vaccine that was safely administered to more than 9,000 participants in MHRP’s RV144 Thai trial, the first human vaccine trial to demonstrate modest efficacy in preventing HIV-1 infection. B.63521 is a recombinant protein developed by the National Institute of Allergy and Infectious Diseases, one of the National Institutes of Health.