Doctors said a London man with HIV has become the second known adult in the world to be apparently cleared of the infection since the global epidemic began decades ago, giving hope for a potential cure for AIDS.
The UK researchers say it may be possible to use gene therapy to target the CCR5 receptor in people with HIV, now they know the Berlin patient's recovery was not a one-off. Then in 2017, Gupta took the London patient off of the anti-HIV drugs to see if the transplant had worked as it had in Brown's case: to push the HIV into remission. As such, this procedure is unlikely to become a realistic treatment for HIV in the future-especially given that the antiretroviral drugs prescribed for the infection have been shown to be extremely effective.
Brown, who had been living in Berlin, has since moved to the United States and, according to HIV experts, is still HIV-free.
The London patient said that it was "surreal" and "overwhelming" to have both his cancer and his HIV cured at the same time.
Sixteen months after the procedure (which notably didn't include radiotherapy, unlike the Berlin patient), the London patient discontinued ARV drugs (aka ART therapy), and has now been in HIV remission for over 18 months.
As far as scientists can tell, eighteen months he received his intervention, the London patient is still completely free of HIV.
These findings demonstrate that "the Berlin patient was not an anomaly", the researchers said. He underwent intensive conditioning chemotherapy and whole-body radiation to kill off his cancerous immune cells, allowing the donor stem cells to rebuild a new HIV-resistant immune system.
Although the finding is exciting, it is not offering up a new treatment for the millions of people around the world living with HIV. Brown received two bone-marrow transplants from a donor with a mutation in a protein called CCR5.
The man received a stem cell transplant involving virus-resistant cells, which put his HIV in remission.
Gupta said the method used is not appropriate for all patients but offers hope for new treatment strategies.
Despite this, the success of the London patient remains a step in the right direction. Her group has been working on a way to mutate the CCR5 gene directly in the bone marrow of a person to simulate the effect of the transplants.
Institutions involved in the case include Imperial College London, University College London, and Cambridge and Oxford University. "amfAR's investments in innovative and forward-thinking projects like ICISTEM give us the opportunity to learn which factors will form the scientific basis of a cure for HIV".
That risk is one reason why a stem cell transplant is never going to be a first-option treatment for HIV. "At the moment the only way to treat HIV is with medications that suppress the virus, which people need to take for their entire lives, posing a particular challenge in developing countries", said Gupta from University College London (UCL), the study's lead author "Finding a way to eliminate the virus entirely is an urgent global priority, but is particularly hard because the virus integrates into the white blood cells of its host", he said in a statement.