Small Study Shows Modified Immune Cells Suppress HIV in Two Patients

Scientists are testing a modification of CAR-T cell therapy, a treatment widely used for certain cancers, to see if it can help fight HIV. On Tuesday, researchers said a single dose of the revved-up immune cells strongly suppressed HIV in two people — one for nearly a year and the other for nearly two years — after they stopped their usual antiviral medicines.

The findings were presented at a meeting of the American Society of Gene and Cell Therapy in Boston. The study leader said the sustained responses were provocative given the challenge of finding an HIV cure. Larger and longer studies are required to establish whether the therapy can provide lasting benefit.

40 million people live with HIV worldwide.

Current medicines can keep the virus at undetectable levels and turn AIDS into a manageable chronic condition, but only if patients can access the drugs and adhere to lifelong treatment. The virus hides in reservoirs in the body and typically rebounds quickly if treatment stops.

Researchers have sought a cure for decades, examining rare genetic mutations that confer natural resistance and cases in which stem cell transplants from donors with such mutations have led to remission in patients who also had cancer. Those transplants carry high risks and are not feasible for most people with HIV.

How the CAR-T Approach Was Adapted CAR-T therapy involves extracting a patient's T cells, genetically modifying them into living drugs, and infusing them back into the body. For HIV, scientists created CAR-T cells with two features: they are programmed to locate and kill HIV-infected cells, and they are engineered to resist infection by the virus itself.

The added protection is intended to allow the cells to multiply sufficiently to control the virus over time. In the experiment, participants stopped their regular HIV medicines on the day they received the CAR-T cells. Different dosing strategies were tested.

No serious side effects occurred. The first three patients showed no response and resumed standard treatment. Six others received a small dose of chemotherapy beforehand to create space for the new cells. Two of those patients saw their HIV levels drop to undetectable, with only occasional small increases.

A third had a temporary response before resuming regular medicine. All three responders had begun HIV treatment soon after infection, which is associated with smaller viral reservoirs and stronger immune systems.

One gene therapy expert not involved in the study described the positive responses as fascinating but said additional research is needed to determine whether the CAR-T approach works. Another researcher said the strategy is exciting because it enhances the immune system's existing capabilities.

The data come from an early-stage study. Further trials will be required to assess safety, scalability and long-term effectiveness.