SA scientists release promising HIV cure trial results
South African scientists have released the findings of the first HIV cure trial in Africa with promising results showing viral suppression in 20% of women who stopped taking antiretroviral therapy (ART) after 18 months.
The study involved 20 women who tested positive for HIV at the Females Rising through Education, Support and Health (Fresh) clinic in Umlazi, KwaZulu-Natal, and started taking antiretroviral treatment a day after knowing their status.
The women aged between 23 and 32 and were living with HIV-1 subtype C, the most common HIV-1 strain in Southern African, which also represents 50% of infections worldwide.
They had been on antiretroviral therapy for at least six years before they joined the study, which involved stopping the therapy and started taking an “intervention” of three products. The study was conducted from July 2022 to January 2024.
According to the research findings, 20% of participants (four women) were able to control viral load to undetectable for a median of 1.5 years after they stopped taking antiretrovirals (ARVs), while 80% did not control their viral load and had to restart them. Viral suppression is defined as having less than 200 copies of HIV per millilitre of blood, which helps keep the infected person healthy and prevents transmission.
The research and laboratory investigation was led by the University of KwaZulu-Natal’s Africa Health Research Institute director for basic and translational science Professor Thumbi Ndung’u.
He said the objective of the study was to assess the safety and efficacy of the product “intervention”, which included two broadly neutralising antibodies — VRC07-523LS and CAP256V2LS — that bind to HIV and stop it, as well as Vesatolimod, which binds to human immune cells and activates the immune response against HIV.
At the presentation of the findings on Friday, he said the hope was to test the immune response to develop an alternative treatment that people could take for two to three years rather than having to take ARV every day for the rest of their lives.
“We first confirmed in the laboratory whether the virus could be inhibited with the two antibodies and the women’s CD4 count (the measure of a type of white blood cells crucial for fighting infections) had to be above 500. Safety was very important because it was the first time that the three drugs were being tested,” Ndung’u said.
“We then asked the participants under close medical observation to stop antiretroviral therapy, to see whether the virus will rebound. It was a small study, but what we found is that four out of 20 participants were able to control the virus without anti-retrovial therapy,” he said.
“This is not a cure for HIV, because we cannot give patients something that only worked in 20% of participants, but it is a step in the right direction. We hope we can improve on this approach and maybe next time do study where we can have 50%.
He said Africa was taking the lead in developing solutions and that while this product would not be tested further, “there might be other products coming out further along”.
Because the participants had started antiretroviral therapy within a day of being diagnosed with HIV, their bodies’ immune systems had had very little exposure to the virus.
“We wanted to see how long it takes for the viral load to rebound. If you stop taking ARV today, within two weeks the virus will rebound,” Ndung’u said.
When the virus rebounded to a viral load of 1000 within 16 weeks for seven of the participants, they went back onto antiretroviral therapy.
“So, we can say they did relatively well compared to someone who just stops treatment and then we had another group of seven that took between 16 weeks and 44 weeks for the virus to rebound which was when the study was meant to end. They went back onto ART and there was no problem with drug resistance,” he said.
None of the participant’s CD4 counts dropped below 350 before they were put back on antiretroviral therapy, so their immune systems were still healthy. Six participants did not need to restart treatment after 44 weeks and of those, four finished an entire year without needing to start ARVs.
The four women chose to remain off ARVs under close clinical monitoring, visiting the clinic once a week, and 18 months later still showed no signs of the virus while one woman went on to reach 2.5 years without the virus rebounding.
According to United Nations Aids statistics, sub-Saharan Africa remains the region most heavily affected by HIV worldwide, accounting for 67%, of which about 53% are women.
dung’u said most clinical HIV cure trials around the world, largely in the United States, have focused on Caucasian men, which is why it had been important to do a study with women.
“Women represent less than 20% of participants in HIV cure trials. So that means that the products being tested, if they don’t work in women, or if they cause some side effects in women we would not know, and that’s why it was very important for us to do this study to see whether we can induce ART free control of HIV in women, “ he said.
Professor Krista Dong, of Fresh, said the “complicated” trial was particularly important because of the dearth of HIV research involving women in Southern Africa.
“We have no idea really, whether an intervention that we put in Caucasian men in San Francisco is going to work in a 13-year-old girl in Umlazi,” she said.
“We do know that there are differences, hormonal differences, and differences culturally, where say, someone in San Francisco will pop a pill for PrEP [pre-exposure prophylaxis, taken to prevent getting HIV from sex or injection drug use] every day, whereas women say no, that’s not for us, we prefer injection. You have to consider the local context.”