Stem cell transplant 'cures' HIV: study
Three years after receiving a stem cell transplant, a US patient has been cured of HIV, said a team of German doctors whose research was published in the peer-reviewed journal Blood on Wednesday.
The results suggest the first such cure for the virus that causes AIDS, though experts caution that the bone-marrow transplant technique used would not be safe or feasible for the wider population.
"Our results strongly suggest that cure of HIV has been achieved in this patient," said the study in the official journal of the American Society of Hematology.
The subject, an American in his 40s who is often referred to as the "Berlin patient," received a stem cell transplant as treatment for acute myeloid leukemia in 2007.
The stem cells came from a donor with a rare gene mutation that makes it impossible to contract HIV.
The study, first released in late 2008, showed no sign that HIV had re-emerged even though the patient had ceased anti-retroviral therapy to suppress HIV.
The latest findings show that, three years later, the patient continues to have no trace of either the virus or leukemia.
"I am very excited about it. I have been for a couple of years since it was first reported," said David Baltimore, a co-recipient of the Nobel Prize in Medicine in 1975.
"You can't have absolute assurance on the basis of one patient but the likelihood was from the beginning that this should work if you can do it," he said.
"The fact that the one patient who was treated then was effectively cured is I think a very strong argument that you want to continue this kind of approach to the HIV problem."
Baltimore founded a biotech company that is working on developing its own stem-cell HIV/AIDS therapy that works functionally the same as the German team's, and is in the process of organizing clinical trials, he said.
The approach used by the German team, led by Kristina Allers and Gero Hutter at Charite - University Medicine Berlin, was to find a donor with the CCR5 gene mutation.
The condition, found in about one in 100 Caucasians, prevents HIV infection from taking hold in the cells.
The doctors then used stem cells from the donor in a bone marrow transplant to the patient. However bone marrow transplants carry major risks and around 30 percent of patients do not survive.
Jay Levy, an AIDS and cancer researcher in the School of Medicine at the University of California, San Francisco, described the latest research as evidence of a "functional cure."
"I mean, one person is not sufficient. It is an encouraging first step but you really need to show it again," he said.
"I always look on this as a direction for future approaches, recognize what the problems are and then see if we can do better and I have faith in my scientific colleagues to come up with something better."
Levy and his team are also looking at ways to manipulate a patient's own stem cells so that they do not express the receptors that allow HIV infection, much like the CCR5 mutation.
As for the study's assertion that a cure has been found, Levy said more time would be needed to say that for sure.
"Anyone in the cancer field will say fine that's good but three years is not enough to say you've cured anything with cancer, and we would say the same thing," said Levy.
"We will know that in 10 years," he added.
"It is too early to say you've cured, but my Lord, they have done a nice job."
© 2010 AFP