The National Institutes of Health (NIH)-funded HIV Vaccine Trials Network (HVTN) has started enrolling participants in a Phase 1 clinical trial to test a “second-generation” HIV vaccine candidate, meaning the vaccine is identical to the first generation candidate but it includes a special additive to enhance the vaccine response. The additive, or adjuvant, is granulocyte-macrophage colony-stimulating factor (GM-CSF), a “normal human protein that promotes the initiation of immune responses,” according to GeoVax Labs Inc., the vaccine developer.
“In the non-human primate model, co-expression of GM-CSF in the DNA prime achieved a 90% per exposure reduction in infection, a significant improvement over the unadjuvanated vaccine,” according to the company press release. “This difference in vaccine efficacy translated into 70 percent of vaccinated animals being protected against 12 repeated rectal challenges.” If all goes well the company will move the boosted vaccine into Phase 2a/2b efficacy testing. The first-generation candidate is currently in a Phase 2a clinical trial.
The new trial, dubbed HVTN 094, will enroll 40 subjects to receive the vaccine and eight to receive a placebo to be studied at four U.S. trial sites – the University of Alabama at Birmingham; Brigham and Women’s Hospital, Boston; the University of Rochester; and the San Francisco Department of Public Health. Researchers will attempt to determine the safety and immunogenicity of the GM-CSF boosted vaccine. They hope to have fully enrolled the trial by November.
In related news, a combo vaccine targeting both HIV-1 and tuberculosis simultaneously showed promising results, as reported in this article in the May 2012 issue of Clinical and Vaccine Immunology. Chinese researchers used antigens from both pathogens in a mice model and successfully induced cellular immune responses to both HIV and TB.