Experts have offered caution about hopes of a "cure" for HIV after it was announced that a second patient has achieved full remission after stem cell therapy.
The patient was given a stem cell transplant for haematological disease – but treated with cells also known to be resistant to HIV, it has been announced.
The male patient, who wants to stay anonymous, lives in the UK and was diagnosed with HIV-1 in 2003. He went on antiretroviral therapy in 2012.
He then developed Hodgkin’s lymphoma and was offered a stem cell transplant.
Doctors were able to find a donor with genetic protection against HIV-1 given by two copies of the CCR5 allele gene.
It is the second known case of a patient being "cured" of HIV after a stem cell transplant. The first patient, in Berlin, was being treated for leukaemia.
Antiretroviral therapy was continued for 16 months after the transplant, after which regular testing confirmed that the patient’s viral load was undetectable, and his immune cells remain unable to express the CCR5 receptor.
The doctors responsible for the treatment say it could not be offered to many patients because the stem cell transplant procedure is highly toxic – and carries significant risks of side effects.
They say the latest procedure was less toxic than the original Berlin treatment as it did not include total body irradiation.
Full details of the case of sustained HIV-1 remission were published last night in Nature. The patient has now been in drug-free remission for 18 months and the doctors say it is premature to announced that he has been "cured."
The case study states: "Replacing immune cells with those that don’t have the CCR5 receptor appears to be key in preventing HIV from rebounding after the treatment.”
Professor Ravindra Gupta of University College London, UK, and Cambridge University, UK, said: “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.
“While it is too early to say with certainty that our patient is now cured of HIV, the apparent success of haematopoietic stem cell transplantation offers hope in the search for a long-awaited cure for HIV/AIDS.”
Analyst Dr Christopher Pace, director of infectious diseases at GlobalData, said: "The news does not represent a general path to a cure for other HIV patients; rather, it simply provides more hope to the medical and scientific communities that their efforts towards a cure are not in vain."
Gupta, R. et al. HIV-1 remission following CCR532/32 haematopoietic stem cell transplantation. Nature 5 March 2019; doi: 10.1038/s41586-019-1027-4.
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