A second patient has been cured of HIV, following stem cell transplants from donors with a HIV-resistant gene, researchers say.
The findings were announced after extensive blood and tissue tests showed no signs of viral reactivation, 30 months after the man stopped taking antiretroviral treatment.
“We propose that these results represent the second ever case of a patient to be cured of HIV,” lead author Professor Ravindra Kumar Gupta, at the University of Cambridge, said in a statement.
“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,” he said.
Professor Gupta’s patient, known as the London patient, was treated with a stem cell transplantation and chemotherapy as part of the treatment for his stage IVb Hodgkin lymphoma.
The donor cells carried a gene resistant to HIV, a mutation of the CCR5 gene. The CCR5 gene is a receptor found on white blood cells that is used by the virus to enter the cells.
The London patient’s case was first announced in 2019, when scientists announced that his HIV was in remission. In the new paper, the authors report that tests on his blood, cerebrospinal fluid, intestinal tissue and lymphoid tissue found no active viral infection.
In addition, the patient’s CD4 cell count was healthy, and around 99% of his immune system cells had been derived from the donor’s stem cells.
Professor Gupta and colleagues did find remnants of integrated HIV-1 DNA in the tissue samples, which they regard as “fossils”. These are thought to be unlikely to be able to reproduce the virus and were also found in the Berlin patient.
Now, the London patient has named himself as Adam Castillejo, according to the New York Times. “This is a unique position to be in, a unique and very humbling position,” he said. “I want to be an ambassador of hope.”
Mr Castillejo’s treatment was less invasive than the Berlin patient’s, which included total body irradiation, two rounds of stem cell transplant and a more intensive chemotherapy regimen.
Nevertheless, Professor Gupta said the London patient’s would not be offered widely to patients who were being treated well with traditional antiretroviral therapy.
“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,” he said.
However, studies into a potentially safer cure, CCR5 gene editing, are currently under way and the results of these may be available in the next few years.
There were many ethical and technical barriers to overcome before this was a viable widespread cure though, co-author Dr Dimitra Peppa, of the University of Oxford, said in a statement.
The results were exciting, Professor Sharon Lewin, from the University of Melbourne, told TMR.
Usually people rebound two or three weeks after stopping their antiretroviral medication, so the extended period of remission was encouraging, she said.
Nevertheless, she said it might be too early to use the word “cure”.
“If you treat someone with cancer and you want to reassure them that they are cured, you can usually tell people, ‘We have followed three million people for five years and none of them have rebounded. We’re pretty sure you are ‘cured’,” she explained.
The Lancet HIV; https://doi.org/10.1016/S2352-3018(20)30069-2