A particularly promising finding of the RIO trial was that the antibodies also affected dormant HIV hiding out in some cells. These reservoirs are how the virus rebounds when people stop treatment, and antibodies aren’t thought to touch them. Researchers speculate that the T cells boosted by the antibodies can recognize and kill latently infected cells that display even trace amounts of HIV on their surface.
The FRESH intervention, meanwhile, targeted the stubborn HIV reservoirs more directly through incorporating another drug, called vesatolimod. It’s designed to stimulate immune cells to respond to the HIV threat, and hopefully to “shock” dormant HIV particles out of hiding. Once that happens, the immune system, with the help of the antibodies, can recognize and kill them.
The results of FRESH are exciting, Ndung’u says, “because it might indicate that this regimen worked, to an extent. Because this was a small study, it’s difficult to, obviously, make very hard conclusions.” His team is still investigating the data.
Once he secures funding, Ndung’u aims to run a larger South Africa-based trial including chronically infected individuals. Fidler’s team, meanwhile, is recruiting for a third arm of RIO to try to determine whether pausing antiretroviral treatment for longer before administering the antibodies prompts a stronger immune response.
A related UK-based trial, called AbVax, will add a T-cell-stimulating drug to the mix to see whether it enhances the long-lasting, vaccine-like effect of the antibodies. “It could be that combining different approaches enhances different bits of the immune system, and that’s the way forward,” says Fidler, who is a co-principal investigator on that study.
For now, Fidler and Ndung’u will continue to track the virally suppressed participants — who, for the first time since they received their HIV diagnoses, are living free from the demands of daily treatment.
This story originally appeared at Knowable Magazine.
