The clinical trial of a possible HIV vaccine has been abandoned after an interim review of the vaccine showed no effective protection from HIV.
The HVTN 702 study, begun in 2016, was being led by the National Institute of Allergy and Infectious Diseases (NIAID). Over 5,400 HIV-negative individuals whose ages ranged from 18-35 took part in the study across 15 sites in Africa.
After showing modest levels of protection in an earlier trial in Thailand, the testing proceeded with a modified version of the vaccine meant to target the strains of HIV most prevalent in South Africa.
For the study, 2,694 individuals received the investigational vaccine regimen while 2,689 volunteers received a placebo.
An interim review of the study by an independent data and safety monitoring board in January showed 129 HIV infections occurred among the vaccine recipients, and 123 HIV infections occurred among the placebo recipients.
“An HIV vaccine is essential to end the global pandemic, and we hoped this vaccine candidate would work. Regrettably, it does not,” said NIAID Director Anthony S. Fauci in a statement. “Research continues on other approaches to a safe and effective HIV vaccine, which I still believe can be achieved.”
While the HVTN 702 study will be halted, there are two other HIV vaccines – Imbokodo and Mosaico – currently in late-stage trials.
Launched in 2017 in South Africa, human trials of Imbokodo (like Mosaico) attempt to invoke an immune response to a variety of HIV strains using a “mosaic” of immunogens via six injections over four sessions.
Mosaico began trials in November of 2019 in South Africa as well but also across 57 sites in the United States, Latin America, and Europe.