Experimental HIV vaccine unsuccessful in preventing HIV
The NIH discontinued the administration of an experimental HIV vaccine after researchers learned that it was not working.
The agency said the National Institute of Allergy and Infectious Diseases (NIAID) stopped giving the vaccine as part of the HVTN 702 clinical trial after an independent data and safety monitoring board found that the regimen did not prevent HIV.
“An HIV vaccine is essential to end the global pandemic, and we hoped this vaccine candidate would work. Regrettably, it does not,” NIAID Director Anthony S. Fauci, MD, said in the release. “Research continues on other approaches to a safe and effective HIV vaccine, which I still believe can be achieved.”
The trial, a phase 2b/3 study that enrolled 5,407 HIV-negative sexually active men and women aged from 18 to 35 years, began in South Africa in 2016. According to NIAID, the trial was examining an investigational, prime-boost vaccine regimen based on the regimen tested in the RV144 clinical trial in Thailand. That trial, which was led by the U.S. Military HIV Research Program and the Thai Ministry of Health, used the only vaccine regimen ever to demonstrate protection against HIV.
During the HVTN 702 trial, participants were randomly assigned to receive the investigational vaccine regimen (n = 2,694) or placebo injections (n = 2,689). The injections were administered six times over 18 months.
An interim analysis examined the number of HIV diagnoses after at least 60% of participants had been in the trial for more than 18 months, a period long enough for the vaccine regimen to stimulate an immune response. At that point, 252 HIV infections — 129 among vaccine recipients and 123 among placebo recipients — were reported. According to the release, the data and safety monitoring board concluded that the investigational vaccine had not demonstrated any efficacy and recommended stopping any further vaccinations. They did, however, recommend that participants stay in the study for follow-up.
“The people of South Africa have made history by answering this important scientific question. Sadly, we wish the answer was different,” HVTN 702 Protocol Chair Glenda Gray, MBBCH, FCPaed, said in the release. “We will continue to explore promising avenues for preventing HIV with other vaccines and tools, both in South Africa and around the world.” – by Caitlyn Stulpin
Disclosures: Infectious Disease News could not confirm relevant financial disclosures at the time of publication.