More than 30 years into the HIV/AIDS pandemic, the medical fraternity is still on an elusive quest to find a cure.“You have to understand that achieving a cure is one of the greatest scientific challenges ever undertaken,” said Dr Robert Redfield, Professor of Medicine and Division Head, Clinical Care and Research, Institute of Human Virology (IHV) at University of Maryland School of Medicine. Redfield is the principal investigator in a five-year programme between Botswana government and IHV known as Botswana-University of Maryland School of Medicine Health Initiative (BUMMHI) to combat HIV/AIDS.
Discussing ‘Current Global Innovations to find an HIV cure’ during the 6th Botswana International AIDS Conference held in Gaborone recently, Dr Redfield noted progress on AIDS as one of the most remarkable success stories in the history of biomedical research but said finding a cure, or cures, will take time, and a continued investment in research. Of the estimated 78 million people globally who have been infected with HIV, only one has been cured.Timothy Ray Brown, better known as the Berlin patient, was diagnosed with HIV in 1995 and then with leukemia in 2006. He was treated with a bone marrow transplant from a person with something called a CCR5 receptor mutation, a rare genetic anomaly that makes people naturally resistant to HIV, and it super-charged his immune system.
Brown then stopped taking his AIDS medication and, a decade later, there is still no sign of the virus in his body.
Dr Redfield noted that four main approaches to a classic cure, some more promising than others, have been tried, but so far without success. Attaining a sustained viral remission, which would allow anti-HIV medications to be stopped for long periods of time without fear of viral rebound, is “likely more feasible,” he said. For such an approach to work, “you need to start with a small reservoir and a competent immune system. In other words, he explained further, “patients need to be treated as soon as possible after infection,” a development that is now recognised in new World Health Organisation (WHO) treatment guidelines that Botswana adopted in June.
“This would reduce the growth of the reservoir and the overall damage to the immune system,” he said. Therapeutic vaccines are another, more practical approach. There has been some promising research with vaccines that sharply reduce the level of virus in some patients (about 20 per cent), but the levels creep back up. The next best hope is gene editing, using tools like CRISPR to remove HIV from a person’s DNA. This has been done successfully in animals but, again, Dr Redfield said doing it in humans on a large scale seems impractical.
If the virus can’t be eliminated, then it needs to be suppressed. That is done with drugs, antiretroviral cocktails that stop or slow down the AIDS virus from replicating. An estimate 269100 HIV-positive Batswana are on ARVs, representing coverage of 87.2 percent. According to Senior Consultant Virologist at Botswana Harvard Partnership Dr Madisa Mine, 62 percent of them have viral suppression. While these are evidently effective, the drugs have to be taken for life, and they have side effects like hiking the risk of heart disease.