GeoVax Labs has completed enrollment for a phase IIa clinical trial testing its HIV/AIDS vaccine. The vaccine is being developed for use in uninfected people to prevent infection should they be exposed to the virus. The trial, designated HVTN 205, is being conducted by the HIV Vaccines Trials Network (HVTN), which is funded by the National Institute of Allergy and Infectious Diseases, part of the National Institutes of Health. A total of 299 participants are enrolled in HVTN 205.

GeoVax also announced the unblinding of data for neutralizing antibody (Ab) responses in part 1 of HVTN 205 - showing elicitation of unexpectedly high response rates of neutralizing antibody for tier 2 isolates of HIV-1. Of 46 tested vaccine recipients, 50% responded with neutralizing activity for tier 2 clade B isolate RHPA; and 26% with neutralizing antibody for tier 2 clade B isolate SC22.3C2. Neutralizing antibodies can block virus from infecting cells by binding to regions of the virus that mediate entry into cells. The elicitation of neutralizing antibody for tier 2 viruses is an important result because tier 2 viruses represent viruses that undergo the most frequent transmission from an infected person to an uninfected person. A new highly sensitive test was used for conducting neutralization tests, which were done at the HVTN laboratories at Duke University.

Patient enrollment for HVTN 205 was conducted at 11 clinical sites in North America and two sites in South America.