The Desmond Tutu HIV Centre greets with great disappointment the news that the Phase 2b/3 HIV vaccine study HVTN 702 conducted by the HIV Vaccine Trials Network has been stopped by the National Institute of Allergy and Infectious Diseases (NIAID), the trial sponsors. The decision comes after a recommendation from the independent Data and Safety Monitoring Board (DSMB). The data viewed by the DSMB during an interim data meeting last week revealed that protocol pre-specified futility criteria had been met. It is important to note that the DSMB did not express any concerns about safety or harm, rather that the vaccine candidate regimen did not prevent HIV infection.
The study, named HVTN 702 or Uhambo, began in 2016 and was testing an investigational prime-boost vaccine regimen based on the only vaccine regimen to ever show protection from HIV. The vaccine regime was tested in the RV144 clinical trial in Thailand where it reduced HIV infection by 30% after 3 years. This regimen was then adapted to the HIV subtype Clade C, the most common in Southern Africa and a further two boosts were added. The regimen showed promising immunogenicity in the earlier phase HVTN 097 and HVTN 100 studies.
Linda-Gail Bekker, HVTN 702 Co-Chair, Deputy Director of the Desmond Tutu HIV Centre and PI of the UCT Clinical Trials Team said that “the extraordinary effort that went into recruiting and implementing a trial of this size and complexity and to the very high standard we have seen to date, makes me proud to be a South African. But these incidence rates should also spur us on as South Africans to regroup to find new solutions to our HIV epidemic as soon as possible.”
The DSMB praised the HVTN team on their efforts in conducting the trial and thanked those that participated. NIAID and the HVTN 702 study team are working at a thorough analysis of the study data, in order to guide future vaccine developments. The findings will be disseminated to the public as soon as possible.
Sheetal Kassim, Principal Investigator at the Emavundleni clinical research site, says that her team is not discouraged by the end of the trial. “Although the result is disappointing and not one that we had hoped for, it is still an important result that will help guide future research. We move on and work harder to find prevention methods that can tackle this difficult problem,” she said. Dr. Kassim also noted that her team is moving forward with determination to continue conducting quality research.
As part of the NIH’s investment in multiple approaches to prevent HIV, there remain two other late-stage, multinational vaccine trials that are ongoing. Both trials (HVTN 705; Ombokodo and HVTN 706; Mosaico) are testing a novel mosaic vaccine regimen, which is a different vaccine concepts to the one that was being tested in HVTN . A third rial, the Phase 2b PrEPVacc study, is also assessing the combination of an HIV vaccine and pre-exposure prophylaxis (PrEP) in sub-Saharan Africa.
In addition to these ongoing vaccine studies, the Antibody Mediated Protection (AMP) program is testing passive antibody administration as a prevention method in two safety and efficacy trials (HVTN 703/HPTN 081 and HVTN 704/HPTN 085).
Professor Graeme Meintjes, Principal Investigator for the the CIDRI-Africa Khayelitsha clinical trial site, said that while this particular vaccine will not be taken forward, there are still many important lessons that will be learnt from the information: “The finding that the HVTN702 vaccine does not protect people from HIV infection is a huge disappointment for the participants, research teams and scientists who have worked together on this trial. Nonetheless, we knew from the start that this was one of the possible outcomes as the trial set out to answer the question of whether the vaccine was effective and safe. We have definitively answered these questions in this extraordinarily large and complex clinical trial that has been conducted to the highest scientific standards. I would particularly like to acknowledge all the participants at our site in Khayelitsha and across the country – the information and samples that have been collected from them in this trial will inform future efforts to prevent HIV with a biomedical intervention.”
The University of Cape Town Clinical Trials Unit (UCTCTU) is based at the Desmond Tutu HIV Centre (DTHC) and headed by Professor Linda-Gail Bekker. It is a cohesive, integrated unit with demonstrated capacity to participate in the breadth of studies from the Division of AIDS (DAIDs) appointed networks. The six Clinical Research Sites that make up the UCTCTU are known to DAIDs either as accredited sites (South African Tuberculosis Vaccine Initiative- SATVI, Groote Schuur Hospital-GSH, Emavundleni-EMA, and UCT Lung Institute-UCTLI) or as protocol-specific sites (Wellcome Centre for Infectious Diseases Research in Africa – CIDRI-A and Masiphumelele-MASI CRSs).
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