South Africa is on track to produce the world’s first licensed HIV/AIDS vaccine.
During the 21st International AIDS Conference in South Africa last month (18-22 July ), Glenda Gray, president of the South African Medical Research Council, said that they are undertaking a large-scale trial to assess whether HVTN 702 vaccine could prevent South African adults from getting HIV.
Carl Dieffenbach, director of the US National Institute of Health’s Division of AIDS, explained that it has taken seven years to reach this stage.
Dieffenbach added that he US-based HIV Vaccine Trials Network, in collaboration with South African researchers, relied on the findings of the RV144 trial, which had an efficacy of 31 per cent in Thailand, to conduct HVTN 100, a smaller initial trial.
“HVTN 100 used the same vaccines that RV144 tested, but made them specific to the subtype of HIV found in southern Africa,” said Linda-Gail Bekker, deputy director of the South Africa-based Desmond Tutu HIV Centre, in a statement. “We also added a booster injection to prolong the period of protection.”
Bekker added: “All the criteria were met unequivocally and, in many instances, the HVTN 100 outcomes exceeded both our own criteria and the immune responses seen in RV144.”
HVTN 702 will seek to confirm findings from HVTN 100 that the modified RV144 regimen is safe, and is being hailed as an important step towards a preventive cure.
The placebo-controlled study will enrol 5,400 HIV-negative men and women at 15 research sites across South Africa, and is to begin in November this year after regulatory approval. Participants will receive five injections over the course of a year.
“After 24 months we’ll look at potency, and at 36 months we’ll assess durability. We hope to have results in five years. We’re looking for efficacy of 50 per cent,” Gray added.
According to Gray, if the HVTN 702 trial is viable, the target will be to provide the vaccine to young girls in schools before they are sexually active.
Another trial addressing whether broadly-acting neutralising antibodies could protect against HIV is underway in Sub-Saharan Africa.
The HVTN 703/HPTN 081 has enrolled 1,500 heterosexual women from Botswana, Kenya, Malawi, Mozambique, South Africa, Tanzania and Zimbabwe.
Researchers are studying the safety and tolerability of a broadly-acting neutralising antibody called VRC01, given by infusion, and what concentration is required for effective prevention.
Bekker says these trials could have an impact on reaching the 2030 goal of zero new HIV infections.
Nyarodzo Mavis Mgodi, director of the Microbicide Trial Network’s collaborative project between the University of Zimbabwe and the US-based University of California-San Francisco, tells SciDev.Net: “If we establish that broadly neutralizing antibodies are potent and will prevent HIV acquisition, then a whole set of scientific breakthroughs could well follow.”
According to Mgodi, the findings of the trials could help “researchers develop an HIV vaccine faster and more efficiently”.