Michael Gwarisa
Canada has recorded its first possible HIV cure in a 62-year-old man who has remained in sustained remission following a bone marrow transplant, according to a report from the University of Toronto.
The case, known as the “Toronto patient,” was developed through a collaboration between clinicians and researchers at University Health Network, Unity Health Toronto and the University of Toronto.
According to the university report, the findings were presented at the Canadian Association of HIV Research Conference and mark the first documented case in Canada of sustained HIV remission without antiretroviral therapy (ART).
The research was co-led by Sharon Walmsley, director of the HIV clinic at UHN, and Mario Ostrowski, a clinician-scientist at St. Michael’s Hospital, Unity Health Toronto.
According to the report, the patient was first diagnosed with HIV in 1999 and had lived with the virus for 27 years while on continuous ART, which kept viral levels suppressed.
In 2021, he was diagnosed with acute myelogenous leukemia and underwent a bone marrow transplant at Princess Margaret Cancer Centre. Doctors selected donor stem cells carrying a rare “delta-32” mutation in the CCR5 gene, which makes cells resistant to HIV infection.
According to researchers, the CCR5 receptor is the main entry point HIV uses to infect human immune cells. People with the delta-32 mutation do not produce this receptor, making them naturally resistant to infection.
Ostrowski noted that about one per cent of people of European ancestry carry this mutation.
“A bone marrow transplant from these donors can provide a potential cure,” he said, according to the University of Toronto report.
The patient stopped taking ART in July 2025 and, as of April 2026, remains HIV-undetectable, indicating sustained remission. According to the researchers, if the virus remains undetectable for two and a half years after stopping treatment, he would become one of only about 10 people globally considered cured of HIV.
Walmsley said the case adds to growing evidence that an HIV cure is possible.
“The small but growing number of these cases prove an HIV cure is possible,” she said, according to the report.
Researchers observed a continuous decline in HIV levels over five years after the transplant, using highly sensitive testing methods. They also recorded a significant reduction in viral DNA, including dormant HIV reservoirs that typically persist even under treatment.
According to the University of Toronto, these reservoirs remain one of the biggest barriers to curing HIV because the virus can remain hidden and reactivate if treatment stops.
Scientists were also unable to isolate live virus from the patient’s white blood cells or detect HIV-specific immune responses, further supporting evidence of long-term remission.
However, researchers caution that bone marrow transplants are not a standard HIV treatment. The procedure is highly risky, expensive, and only used in cases where patients also require treatment for life-threatening blood cancers.
According to the report, the case provides important scientific insight that could help researchers develop safer and more scalable strategies to eliminate HIV reservoirs in future.
Part of the laboratory work was conducted at the Toronto High Containment Facility at the University of Toronto, which supports advanced infectious disease research, including HIV studies.