The patients had been on long-term antiretroviral therapy for HIV when they developed lymphoma. To treat the cancer, they underwent reduced intensity chemotherapy followed by stem-cell transplants.
Since the transplants, Dr. Henrich has been unable to find any evidence of HIV infection.
Henrich and fellow researcher Daniel Kuritzkes had first announced last year that the men showed no traces of the HI virus eight months after they received the transplants. The men were, however, still on anti-HIV drugs at the time.
Dr. Henrich then withdrew the patients’ antiretroviral therapy and performed several sophisticated tests looking for signs of the virus returning in blood and other tissues. One of the men has now been off treatment with no detectable virus for approximately 15 weeks, and the second man for seven weeks, with similar results.
However, the researchers stressed that is too soon to draw any definitive long-term conclusions that the man have been ‘cured’ of the HIV. More definitive answers will emerge as these patients continue to be closely monitored, they said.
“These findings clearly provide important new information that might well alter the current thinking about HIV and gene therapy,” said Kevin Robert Frost, CEO of amfAR. which helped fund Henrich’s work.
“While stem-cell transplantation is not a viable option for people with HIV on a broad scale because of its costs and complexity, these new cases could lead us to new approaches to treating, and ultimately even eradicating, HIV.”
The first person to be cured of HIV, Timothy Brown (“the Berlin patient”), also underwent a stem-cell transplant in 2007 to treat his leukaemia.
These two new cases differ significantly, however, in that the stem-cell donors of the two men lacked the genetic mutation that renders a person virtually resistant to HIV infection.
Dr. Henrich’s patients also did not undergo the intensive chemotherapy or total body irradiation that preceded Brown’s stem-cell transplant.
“Dr. Henrich is charting new territory in HIV eradication research,” said amfAR Vice President and Director of Research Dr. Rowena Johnston. “Whatever the outcome, we will have learned more about what it will take to cure HIV.”