Supercharging immune cells may help control HIV in the long term

Miracle cancer A treatment that involves engineering a patient’s own immune cells is being repurposed to treat HIV, and early results from two people suggest it holds promise for controlling the virus in the long term.

As part of a clinical trial, scientists took people’s own immune cells and reprogrammed them in the laboratory to recognize and attack HIV in the body. After a single injection of the modified cells, two people with HIV had undetectable levels of the virus, one for about two years and the other for about a year. Both were able to stop taking HIV medications completely.

The two people are part of a small study to test the safety and feasibility of the treatment. The preliminary results were announced last week at the annual meeting of the American Society for Gene and Cell Therapy in Boston.

“These are early days,” says Stephen Deeks, a professor of medicine and HIV expert at the University of California, San Francisco, who led the trial. “If we can provide evidence that this approach is safe and effective, there are a lot of ways we can improve it, to make it less expensive and scalable.”

This technology, known as CAR-T cell therapy, has been used in tens of thousands of patients with difficult-to-treat cancers. A half-dozen or so drugs based on this technology have been approved. The treatment basically works to boost a person’s immune system to directly attack and eliminate cancer cells. More recently, it has also been used successfully to treat severe autoimmune diseases.

“This is very exciting,” says Andrea Gramatica, vice president of research at the AIDS Research Foundation, amfAR, who was not involved in the trial. “The reason this study is particularly significant and significant is that it gives the HIV field real clinical evidence that teaching the immune system to control the virus without antiretroviral therapy is achievable.”

Scientists have been seeking a cure for the human immunodeficiency virus (HIV) since the virus was first discovered in the early 1980s. Antiretroviral therapy prevents the progression of AIDS by suppressing the virus to undetectable levels, but patients must take the drug for the rest of their lives. It has turned HIV into a chronic condition that allows people to have a near-normal life expectancy. However, not everyone with HIV is aware of their status, and in some rural and low-income areas of the world, these medications are still not widely available or affordable.

To date, there have been fewer than a dozen documented cases of sustained HIV cure — known as “functional cure” because the virus is still present in the body but has been suppressed to levels that are undetectable by the immune system and HIV treatment is no longer needed.

Each of these individuals had 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 who had 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 sustained remission “taught us that the immune system can, under the right conditions, eliminate HIV,” says Boro Drobolich, executive director of the Maryland nonprofit Caring Cross, which developed a CAR-T treatment for HIV.

He says stem cell transplants are not scalable. They are intensive procedures that carry serious risks such as graft-versus-host disease, when transplanted cells recognize the recipient’s cells as foreign and attack them.

“What we’re trying to do is intentionally engineer this outcome without needing cancer, without needing a specific donor,” Drobolich says. His organization works to make advanced treatments like CAR-T more accessible and affordable.