Nearly three years after receiving bone marrow stem cells from a donor with a rare genetic mutation that resistsHIV infection - and more than 18 months after he came off antiretroviral drugs - highly sensitive tests still show no trace of the man's previous HIV infection.
Both Brown and the London patient underwent bone marrow transplants because they needed to treat their cancer, not to treat their HIV; and both experienced side effects of rejection at varying levels, since they received cells from an unrelated donor.
Institutions involved in the case include Imperial College London, University College London, and Cambridge and Oxford University.
Now, an global team of scientists led by Ravindra Gupta, a virologist at the University College London, reports a second patient has been in remission for three years following a similar procedure.
"The so-called London Patient has now been off ART for 19 months with no viral rebound which is impressive, but I would still be closely monitoring his viral load", Sharon Lewin, IAS Governing Council Member and Co-Chair of the Towards an HIV Cure initiative, said.
Doctors found a donor with a gene mutation that confers natural resistance to HIV. The "Berlin patient", aka Timothy Ray Brown, now 52 and living in Palm Springs, California, is widely considered cured because he has been HIV-free without anti-HIV drugs for more than a decade.
Approximately 37 million people are now infected with HIV globally, and more than 35 million people have died from AIDS or related illnesses. About 1% of people of European descent have two copies of this mutation and are resistant to HIV infection. The transplanted stem cells can also produce immune cells that go on to attack their new host, a problem called graft vs. host disease. There have been other attempts to discontinue anti-retroviral therapy for HIV+ bone marrow transplant recipients, but in these cases the patient's virus has returned.
These findings demonstrate that "the Berlin patient was not an anomaly", the researchers said.
"CCR5 is something essential for the virus to complete its life-cycle and we can't knock out many other things without causing harm to the patient", said Gupta.
When people have two copies (one inherited from each parent) of this mutation, it prevents blood cells from having a CCR5 receptor. He decided in 2016 to have a stem cell transplant to treat the cancer, the Associated Press reported. Almost one million people die every year from HIV-related causes.
The London patient, whose case will be reported in the journal Nature and presented at a medical conference in Seattle on Tuesday, has asked his medical team not to reveal his name, age, nationality or other details. He used antiretroviral drugs for over ten years until he was diagnosed with acute myeloid leukemia.
That didn't happen with the London patient.