Long-term follow-up of a London hospital patient who became the second person in the world to be cleared of HIV has revealed no signs of any active viral infection for more than two years, doctors have said.
Adam Castillejo, who only recently revealed his identity, achieved "sustained remission" from HIV after being treated at the Hammersmith Hospital in west London.
Scientists did not detect any active HIV virus in the 40-year-old's blood 30 months after his antiretroviral medication, which involves taking drugs to suppress the HIV virus, was discontinued.
While the treatment is high-risk and only suitable for certain patients, the researchers said the results provide evidence that Mr Castillejo is the second patient to be cured of the virus, more than a decade after the first person was declared free from HIV in Germany.
In 2003, Mr Castillejo was diagnosed with HIV infection and developed an Aids defining cancer, advanced Hodgkin's Lymphoma, in 2012.
In 2016, he received a transplant of stem cells from a donor carrying a genetic mutation in the HIV receptor CCR5, which hinders the virus from entering human cells.
Although there was no evidence of any active viral infection in Mr Castillejo, the researchers found remnants of the virus DNA in tissue samples, which they said are unlikely to cause any problems.
Professor Ravindra Kumar Gupta, a virologist at the University of Cambridge and lead author on the study, said: "We propose that these results represent the second ever case of a patient to be cured of HIV.
"Our findings show that the success of stem cell transplantation as a cure for HIV, first reported nine years ago in the Berlin patient, can be replicated."
But he cautioned: "It is important to note that this curative treatment is high-risk, and only used as a last resort for patients with HIV who also have life-threatening haematological malignancies.
"Therefore, this is not a treatment that would be offered widely to patients with HIV who are on successful antiretroviral treatment."
"I want to be an ambassador of hope," says Adam Castillejo, who is the second person to have been cured of H.I.V. https://t.co/TuiPud06aN— NYT Science (@NYTScience) March 10, 2020
Similar therapy has been successful once before with Timothy Ray Brown, known as the "Berlin Patient", who is still free of HIV after being treated in Germany.
His treatment included two rounds of stem cell transplant, as well as a total body irradiation and a chemotherapy drug regimen to target any residual HIV virus.
Mr Castillejo, on the other hand, underwent one stem-cell transplantation and a reduced-intensity chemotherapy drug regimen, without whole body irradiation.
The authors said that while Mr Castillejo's case represents "a step towards a less intensive treatment approach", he will need continued monitoring for re-emergence of the virus.
The case report is published in The Lancet HIV journal and was presented at Conference on Retroviruses and Opportunistic Infections.
Mr Castillejo, who revealed his identity in an interview with the New York Times, is of mixed Spanish-Dutch heritage and said he is "very proud" to consider himself a Londoner.
He was head chef in a corporate dining room when he was diagnosed with cancer in 2011 while working a second job on weekends to save money for travel.
"After a couple of years the chemo became too intense and I could no longer continue to work," his statement said.
"My life fell apart at that stage. I lost my job and I couldn't afford my flat so lost that too.
"I am now starting again, rebuilding my life as I steadily get stronger. The journey has given me the chance to gain more knowledge and understanding about cancer research and the world beyond me.
"Now, I am looking forward to building a new path as an 'Ambassador of Hope' for millions of people around the world living with HIV.
"Whilst my treatment is not possible for all, I hope it will offer scientists insights that can help us on the journey to better treatment and a cure."
Mr Castillejo said he plans to share his experiences through a podcast and his Twitter and Instagram accounts, @londonpatient and LondonPatientofficial, and said he recently began to "rekindle his passion" for cooking as a trained chef.