"There is no virus there that we can measure".
The researchers say it is too early to say the patient is "cured" of HIV.
"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.
Both the first patient to be cured of H.I.V., Timothy Ray Brown, who is now 52 and was cured in 2007, and the new patient, whom scientists refer to as the "London patient", were afflicted with forms of cancer and were given bone-marrow transplants meant to treat their cancers, not the H.I.V virus, according to The New York Times. He remains free of HIV today.
The second person, dubbed "The London Patient", was treated by specialists at the University College London and Imperial College in 2016 and has shown no sign of the virus since. The London patient, who had Hodgkin's lymphoma, is the first adult to be cleared of HIV since Brown.
After the bone marrow transplant, the London patient remained on ARV for 16 months, at which point ARV treatment was stopped.
Most experts say it is unlikely such treatments could be a way of curing all patients.
The approach is not appropriate as a standard HIV treatment due to the toxicity of chemotherapy, he warned, but said he is "hopeful" it will help them develop strategies that might eliminate HIV altogether. About 1 percent of people descended from northern Europeans have inherited the mutation from both parents and are immune to most HIV. He believes translation of the approach into gene therapy could work - though it has not yet been proven - and if so, it could become an option for a large number of HIV patients.
Nearly 1 million people die annually from HIV-related causes.
The London patient, whose case is set to be presented at a medical conference in Seattle on Tuesday, has asked his medical team not to reveal his name, age, nationality or other details.
The results seen in the "London patient", as the person is being identified to protect his identity, are similar to what was discovered in the "Berlin patient" more than 10 years ago.
The patient, who prefers to remain anonymous, remains HIV-free to date. For people without cancer, treatment with antiretrovirals in the long term is preferable to even a short combination of chemotherapy and stem cell transfer. There are complications too.
"But this is not applicable to the millions of people who don't need a stem cell transplant".
Scientists have inched closer to finding the real cure for HIV/AIDS after another man who was until recently HIV-positive was successfully cured of the disease in Britain.
"We can try to tease out which part of the transplant might have made a difference here, and allowed this man to stop his anti-viral drugs". There are now 37 million people infected with HIV, 21 million are on antiretroviral treatment, but drug-resistant strains are becoming more widespread.