Why the Historic HIV Vaccine Clinical Trial was Stopped in South Africa

Mar 16, 2020 | AIDS, HIV, HIV Vaccine Trials Network, HVTN 702, South Africa, Uhambo, Vaccine

Why the Historic HIV Vaccine Clinical Trial was Stopped in South Africa

A prominent clinical trial in South African called “Uhambo” was halted by the Data Safety Monitoring Review Board (DSMB) because the vaccine, HVTN 702, failed to prevent HIV transmission under 18 months into the study.  

It is unfortunate as HIV/AIDs continues to be a pressing problem in this part of the world. The study was cancelled by its primary sponsor—the National Institutes of Health (NIH).

HIV/AIDS in South Africa

Of pressing concern, the country has the highest number of people afflicted with HIV of any country worldwide. It also has the fourth-highest adult HIV prevalence rate based on 2019 United Nations statistics. According to UNAids dataset from the World Bank, the HIV prevalence rate for adults aged 15 to 49 was 37% in Swaziland, 25% in Lesotho, 25% in Botswana, and 19% in South Africa—all of these areas are in the southern part of Africa.

DSMB Position

Sponsored by the HIV Vaccine Trials Network, Catherine Murombedzi of the Scottish Sunday Mail reports that it was cancelled because, as the DSMB reported, “The review showed no significant difference between the two arms of the trial and importantly, no safety concerns. Trial participants are being informed of the stop and will remain in the study for follow-up.”

Based on the RV144 Trial in Thailand

This vaccine was adapted from one tested in Thailand known as RV144. In that study, it evidenced a lower infection rate—by 31%—among those participants who received versus the placebo group, reported Dr. Hunidzarira. The Thailand study was led by the U.S. Military HIV Research Program and the Thai Ministry of Health.

Historic Effort in South Africa

Dr. Portia Hunidzarira, a local researcher with the University of Zimbabwe College of Health Sciences—Clinical Trials Research Centre (UZ-CHS-CTRC), reported that the vaccine development process can take a long time and that despite the halting of the clinical trial of HVTN 702, “a lot has been learned” from this Phase 2B/3 clinical trial involving 5,407 participants. Each participant was injected six times over an 18-month period. A total of 252 infections were reported during the trial.

HVTN 702 was adapted to the HIV subtype Clade C most common in southern Africa, where the pandemic is most pervasive worldwide. Although the study was topped by the DSMB HVTN 702 Protocol Chair Glenda Gray, MBBCH, FC.Paed. (SA) reported, “The people of South Africa have made history by answering this most important scientific question. Sadly, we wish the answer was different.” Gray continued “We will continue to explore promising avenues for preventing HIV with other vaccines and tools, both in South Africa and around the world.” Dr. Gray is president and chief executive officer of the South African Medical Research Council; research professor of pediatrics at the University of Witwatersrand, Johannesburg; and a founding director of the Perinatal HIV Research Unit at Chris Hani Baragwanath Hospital in Soweto, South Africa.

The Mission doesn’t Stop with HVTN

With the development of anti-retroviral therapy (ART), a new lease on life is available for many people infected with HIV. With correct medication and adherence, the HIV virus is suppressed to undetectable levels, and at this level it cannot be transmitted. But there is no cure and the disease is still causing much damage in southern Africa. Although it is unfortunate that HVTN 702 didn’t succeed, much was learned and this doesn’t impact other trials involving HIV prevention worldwide. The quest to find a vaccine continues. 

The HIV Vaccine Trials Network is the world’s largest publicly funded multi-disciplinary international collaboration facilitating the development of vaccines to prevent HIV/AIDs. They have conducted over 50 clinical trials and have made numerous contributions to the field and they will continue to do so.

Lead Research/Investigator mentioned

Glenda Gray, MBBCH, FC.Paed. (SA), DSc

Dr. Portia Hunidzarira, a local researcher with the University of Zimbabwe College of Health Sciences

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