Study: Gene Therapy for HIV Safe, But Effectiveness Still Unclear

Patients doing well a decade later but virus itself not eradicated

Wednesday, May 2, 2012

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WEDNESDAY, May 2 (HealthDay News) -- New research shows that gene therapy can have long-lasting effects on the immune cells of HIV patients -- a promising sign -- even though the specific treatment being studied did not eradicate the virus.
This approach is one of several gene therapy strategies that are being investigated by scientists as possible ways to keep the AIDS virus from spreading in the blood.
In this case, "people were treated by gene therapy and nothing bad happened. It was safe," said study co-author Frederic Bushman, a professor of microbiology at the University of Pennsylvania.
In addition, he said, the treated immune cells managed to remain around for about a decade. "The general picture that emerges about genetic alterations to human immune cells is that they can persist for a long time if you do it right."
The study appears in the May 2 issue of Science Translational Medicine.
Researchers have long been exploring gene therapy -- in which cells in the body are genetically modified -- as a possible treatment for infection with HIV, the virus that causes AIDS. The idea is that the therapy would offer a permanent alternative to costly medications that come with potentially disabling side effects.
"Just think about what an HIV patient has to do: take drugs every day for the rest of his life, and the minute he stops taking them, the virus starts coming back," said John Rossi, chair of the department of molecular and cellular biology at the Beckman Research Institute of the City of Hope, in Duarte, Calif. He was not associated with the new research.
The study looks at 43 HIV-positive patients. Between 1998 and 2002, researchers removed blood from the patients, genetically modified it, and injected it back into them.
The plan was to program immune cells known as T cells to kill HIV cells.
Up to 11 years later, researchers found that all 43 patients are healthy, and 41 still have modified T cells in their bodies. That means the modified cells didn't cause leukemia, as has happened with some similar gene -therapy treatments.
The treatment, however, didn't seem to have had a major impact on the HIV in the patients and "may not have worked at all" on that front, study co-author Bushman said.
Dr. David Looney, director of the Center for AIDS Research at the University of California, San Diego, said the research is still "exciting and promising" since it shows that modified immune cells can last a long time, potentially decades.
Several research projects are continuing to examine gene therapy for HIV patients. There's a caveat, however: If gene therapy treatments become available, they seem likely to be extremely expensive.
But Bushman said that if the gene therapy could someday replace antiretroviral medicines, the cost might still be lower than keeping patients on drugs for rest of their lives.

SOURCES: Frederic Bushman, Ph.D., professor of microbiology, University of Pennsylvania, Philadelphia; John Rossi, Ph.D., professor and chair, department of molecular and cellular biology, Beckman Research Institute of City of Hope, Duarte, Calif.; David Looney, M.D., associate professor and director, UCSD Center for AIDS Research, University of California, San Diego; May 2, 2012, Science Translational Medicine

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