Two HIV positive men have been cleared of the virus and remain so more than three years after bone marrow transplants in Sydney.
One of the two patients, treated at St Vincent’s Hospital in partnership with the University of NSW’s Kirby Institute, is the first known case of HIV being cleared without the use of bone marrow from a donor with a natural genetic resistance to the virus.
Until now, the only person considered to have cleared HIV is an American man, Timothy Ray Brown, who had two bone marrow transplants in Berlin (in 2007 and 2008).
In that case, the second donor bone marrow included both copies of a gene that affords protection against HIV which is found in less than 1% of the population. The man is no longer on antiretroviral therapy and remains clear of the virus.
In the latest breakthrough in Australia, one patient underwent the bone marrow transplant for non-Hodgkin’s lymphoma. In his case, the transplant donor carried one of two possible copies of the gene which affords protection against HIV.
The second had leukaemia and received bone marrow from a donor with no genetic resistance to HIV.
More than three years later, both patients are free of the virus, although they remain on antiretroviral drugs as a precaution.
The Australian study is being presented at the Towards an HIV Cure Symposium today as part of the 20th International AIDS Conference in Melbourne.
Professor David Cooper, the senior author of the study and Kirby Institute director, says it’s difficult to find a match for bone marrow donors and even more so to find one which affords protective immunity against HIV.
While the Sydney results are a significant development, the researchers say bone marrow transplants are not a general functional cure for the up to 38.8 million people infected with HIV world-wide.
Bone marrow transplantation is a difficult and costly procedure which can result in death in 10% or more cases.
Dr Sam Milliken, Director of St Vincent’s Haematology & Bone Marrow Transplantation, says this is a terrific unexpected result for people with malignancy and HIV.
“It is important to caution that at this stage, this form of treatment is far too dangerous for treating patients with HIV alone, but there may be potential for using transplants as an effective treatment modality for HIV down the track,” says Dr Milliken.
The two existing Sydney patients will be the subject of investigations to work out where any residual virus might be hiding and how it can be controlled.
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