Small study hints that revving up immune cells might help fight HIV
WASHINGTON– Scientists are fine-tuning a powerful cancer therapy in the hope it can fight HIV, by boosting patients’ immune cells.
On Tuesday, researchers said a single dose of these regenerated cells strongly suppressed HIV in two people – one for almost a year and the other for almost two years – without requiring their usual medications.
Larger, longer studies are needed to prove whether so-called CAR-T cell therapy could actually offer lasting help against HIV, cautioned Dr. Steven Deeks of the University of California, San Francisco, who led the research.
“We find it provocative that two people had such a sustained response,” he said. “There is a real need for a single, safe and scalable cure…and that is one of the strategies we are pursuing.”
The data is being presented at a meeting of the American Society of Gene and Cell Therapy in Boston.
Nearly 40 million people live with HIV worldwide. Today’s drugs have transformed the virus that causes AIDS from a rapidly fatal disease to a manageable chronic illness, often keeping the virus at undetectable levels, but only if people can afford the drugs and stick to them. The virus hides in the body’s reservoirs and rebounds quickly if people stop treatment.
Researchers have long searched for an elusive cure, looking for clues such as a rare genetic mutation that makes some people naturally resistant to HIV or how a handful of HIV-positive patients who also had certain cancers were declared cured or in long-term remission after receiving a stem cell transplant, which is too risky for most people.
CAR-T therapy involves removing immune soldiers called T cells from a person’s blood, genetically transforming them into “living drugs” and injecting them back into the patient. They are widely used to treat certain types of cancer and are being studied for other diseases.
For HIV, scientists at nonprofit drug developer Caring Cross have created CAR-T cells with two characteristics. They are programmed to better detect and kill HIV-infected cells – and designed to offer protection against infection by the very virus they are designed to fight.
With this extra armor, they should be able to reproduce sufficiently to control HIV, said Boro Dropulić, executive director of Caring Cross.
Deeks’ preliminary experiment tested different dosing strategies in people who stopped their HIV treatment the day they received their CAR-T cells. There were no serious side effects. The first three recipients showed no response and returned to their regular medications.
Six others received a small amount of chemotherapy to make room for new T cells. These two strong responders saw their HIV drop to undetectable levels, only occasionally increasing when the CAR-T cells presumably went back to work. A third patient had a temporary response and resumed regular HIV treatment.
These three patients had all started their initial HIV treatment shortly after becoming infected, Deeks said. This makes sense because people treated early tend to have less hidden HIV in the body and healthier immune systems.
“It’s certainly very fascinating that they had this positive response,” said Dr. Hans-Peter Kiem, a gene therapy expert at the Fred Hutchinson Cancer Center in Seattle, who was not part of the new study. He cautioned that more research will be needed to prove whether CAR-T actually works.
But the strategy is exciting because it “strengthens what our body, our immune system, can already do,” said Andrea Gramatica, vice president of research at amfAR, the Foundation for AIDS Research, which is funding some work to create easier-to-use versions.
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