Novel HIV Vaccine May Offer Continuous Protection

Experimental HIV vaccine could provide long-term protection in areas with high infection rates.

The first new study to evaluate the efficacy of an HIV vaccine was recently launched in South Africa. The trial aims to determine whether this vaccine could potentially defend against HIV in areas where the virus is highly prevalent.

The novel HIV vaccine was adapted from the only vaccine candidate that has shown the ability to protect against the virus, according to a press release from the National Institutes of Allergy and Infectious Disease (NIAID), which is co-funding the trial.

The HVTN 702 trial will enroll up to 5400 HIV-negative men and women between 18- and 35-years-old living in South Africa. The vaccine does not contain HIV, and will not infect any study participants. This trial also is the largest to be conducted in South Africa, a country where more than 1000 people contract the virus each day.

The investigational vaccine was based on a formulation evaluated in the RV144 clinical trial, which was conducted by the US Military HIV Research Program and the Thailand Ministry of Health, according to the NIAID. Results from that clinical trial showed that the vaccine could provide modest protection against new infections.

The novel HIV vaccine candidate was designed to provide larger and continuous protection against HIV, and can even target HIV subtype C, which is common in this area of Africa, according to the study.

HVTN 702 is a combination of 2 investigational vaccines: the canarypox vactor-based vaccine, ALVAC-HIV, and a 2-component gp120 protein subunit vaccine, with an adjuvant to increase the immune response, the NIAID reported. ALVAC-HIV was manufactured by Sanofi, while GSK supplied the protein vaccine and MF59 that will be used as an adjuvant.

“The people of South Africa are making history by conducting and participating in the first HIV vaccine efficacy study to build on the results of the Thai trial,” said HVTN 702 Protocol Chair Glenda Gray, MBBCH, FCPaed (SA). “HIV has taken a devastating toll in South Africa, but now we begin a scientific exploration that could hold great promise for our country. If an HIV vaccine were found to work in South Africa, it could dramatically alter the course of the pandemic.”

The investigational vaccine in the Thailand trial was found to only be 31.2% effective after a 3.5-year follow-up period. In the current study, the design, schedule, and components of the vaccine regimen were altered to increase the amount of vaccine-elicited immune effects, according to the press release.

The NIAID will be responsible for all operational aspects of the trial, and results are expected in 2020. The initiation of the HVTN702 trial commences shortly after interim results from HVTN 100 trial found the vaccine safe in 252 patients.

Scientists will monitor patient safety throughout the trial, and patients will also use the standard of care for preventing a new HIV infection. Any patients who contract HIV during the trial will be referred to medical professionals to receive proper treatment, according to the NIAID.

“If deployed alongside our current armory of proven HIV prevention tools, a safe and effective vaccine could be the final nail in the coffin for HIV,” said Anthony S. Fauci, MD, director of the NIAID. “Even a moderately effective vaccine would significantly decrease the burden of HIV disease over time in countries and populations with high rates of HIV infection, such as South Africa.”