Supercharging Immune Cells May Help Control HIV Long-Term
A miracle cancer A therapy that involves engineering a patient’s own immune cells is being repurposed for HIV, and early results from two individuals suggest it holds promise for long-term control of the virus.
In a clinical trial, scientists took individuals’ immune cells and reprogrammed them in the laboratory to recognize and attack HIV in the body. After a single infusion of modified cells, two HIV-positive people now have undetectable levels of virus – one for almost two years and the other for almost a year. Both were able to completely stop their HIV medications.
The two people are part of a small study to test the safety and feasibility of the treatment. The first results were announced last week at the annual meeting of the American Society of Gene and Cell Therapy in Boston.
“We’re still in the early stages. If we can provide proof of concept that this approach is both safe and effective, then there are many ways to optimize it, to make it more affordable and scalable,” says Steven Deeks, a professor of medicine and HIV expert at the University of California, San Francisco, who led the trial.
The technique, known as CAR-T cell therapy, has been used in tens of thousands of patients with difficult-to-treat cancers. Half a dozen drugs based on this technique have been approved. The treatment essentially strengthens a person’s immune system to directly attack and eliminate cancer cells. Recently, it has also been used successfully to treat serious autoimmune diseases.
“It’s pretty exciting,” says Andrea Gramatica, vice president for research at amfAR, the Foundation for AIDS Research, who was not involved in the trial. “The reason this study is important and particularly important is that it gives the HIV field a real clinical clue that it is possible to teach the immune system to control the virus without antiretroviral treatment.”
Scientists have been searching for a cure for HIV since the virus was first identified in the early 1980s. Antiretroviral therapy prevents progression to AIDS by suppressing the virus to undetectable levels, but people must take medication for the rest of their lives. It has transformed HIV into a chronic disease that allows people to have a near-normal life expectancy. Yet not all people with HIV are aware of their status, and in some rural and low-income parts of the world, these medications are still not widely accessible or affordable.
So far, there are fewer than a dozen documented cases of sustained HIV remission – known as “functional cure” because the virus is still present in the body but is suppressed to undetectable levels by the immune system and anti-HIV drugs are no longer needed.
Each of these people developed cancer and underwent a stem cell transplant as part of their treatment. In all but one of these cases, doctors used stem cells from donors with a rare genetic mutation called CCR5 that naturally prevents HIV from entering and infecting healthy cells. Timothy Ray Brown, known as the “Berlin Patient”, was the first known person to be cured of HIV in this way in 2008.
Examples of prolonged remission “have taught us that the immune system can, under the right conditions, eliminate HIV,” says Boro Dropulić, executive director of the Maryland-based nonprofit Caring Cross, which developed CAR-T therapy for HIV.
But stem cell transplants are not scalable, he says. These are intensive procedures that carry serious risks, such as graft-versus-host disease, when the transplanted cells recognize the recipient’s cells as foreign and attack them.
“What we are trying to do is to achieve this result deliberately without resorting to cancer, without resorting to a specific donor,” says Dropulić. His organization works to make advanced therapies like CAR-T more accessible and affordable.
