Canadian First: Man Living with HIV in ‘Sustained Remission’ After Bone Marrow Transplant

Doctors at UHN's Toronto General Hospital and Princess Margaret Cancer Centre, together with St. Michael's Hospital (Unity Health Toronto), and the University of Toronto, report a case of possible HIV cure following a bone marrow (BM) transplant, in a man dubbed the Toronto patient.

(Toronto, April 25, 2026) — In a Canadian first, clinicians and researchers at University Health Network (UHN), Unity Health Toronto, and the University of Toronto report a case of sustained HIV remission – and possible cure – following a bone marrow transplant for cancer.

The case was led by Dr. Sharon Walmsley, Director of the HIV Clinic at UHN's Toronto General Hospital, and Dr. Mario Ostrowski, clinician-scientist at St. Michael's Hospital (Unity Health Toronto), working in collaboration with transplant and cancer specialists across UHN, Unity Health Toronto, and the University of Toronto.

Presented today at the Canadian Association of HIV Research Conference, the report describes a Toronto individual living with HIV for 27 years who developed acute myelogenous leukemia and underwent a bone marrow transplant.

The bone marrow transplant took place at the Hans Messner Allogeneic Transplant Program at UHN's Princess Margaret Cancer Centre and used donor stem cells with a rare genetic mutation that provides HIV resistance, following an international donor search to identify a suitable match.

Researchers observed a progressive decline in HIV levels in the patient's cells following the transplant. The individual discontinued antiretroviral therapy (ART) in July 2025. As of April 2026, HIV remains undetectable using highly sensitive laboratory testing, and no HIV‑specific immune responses have been detected – a finding consistent with cases considered cured internationally.

Some of the laboratory work supporting this case was carried out in the Toronto High Containment Facility, a specially equipped lab space that allows researchers to study pathogens like HIV in a safe and secure way. Based at U of T, the facility is a key research infrastructure asset for researchers across the city, driving advances in infectious disease prevention, detection and treatment.

Significance

To date, just 10 patients worldwide are considered cured of HIV following similar procedures. The Toronto patient would join the small group if he continues to have undetectable levels of HIV. He is currently considered to be in ‘sustained remission.'

"The small but growing number of these cases prove an HIV cure is possible," says Dr. Walmsley, who is also the Speck Family Chair in Emerging Infectious Diseases and professor at the University of Toronto's Temerty Faculty of Medicine. "Cases such as these provide important information for researchers to find ways to eradicate HIV from the body. It is not possible to offer bone marrow transplant for those without another indication, such as leukemia, given the risks of the procedure."

"HIV infection, although well controlled with ART, still carries enormous stigma and discrimination," says Dr. Mario Ostrowski, who is also the Ontario HIV Treatment Network Applied Research Chair and professor at the University of Toronto's Temerty Faculty of Medicine. "One percent of people of European ethnicity have bone marrows that are resistant to HIV infection. A bone marrow transplant from these donors can provide a potential cure. Transplant provides clues to develop similar, less toxic and less expensive therapies by studying these individuals."

"This case represents years of careful clinical work, close monitoring, and collaboration across specialties," says hematologist Dr. Tommy Alfaro Moya with UHN's Princess Margaret Cancer Centre, who was involved in the patient's post‑transplant care. "This case offers critical insight into how HIV can be eliminated from the body, informing safer approaches in the future."

An estimated 65,270 people were living with HIV in Canada at the end of 2022, according to the Public Health Agency of Canada. The World Health Organization estimates there are more than 40 million people living with HIV globally.

Case Background

The Toronto patient was diagnosed with Stage 4 Burkitt's lymphoma and HIV infection in 1999. He achieved complete remission after chemotherapy and viral suppression with ART. HIV-infected persons need to take antiretroviral therapy (ART) for life, because HIV can form a reservoir in the body that can be awakened if ART is stopped.

More than 20 years later, in July 2020, he developed myelodysplastic syndrome as a long-term consequence of chemotherapy. The condition progressed to acute myelogenous leukemia in November 2021.

Bone marrow transplants using HIV-resistant stem cells are very expensive, and not standard treatment for HIV. They are only considered for patients who also require a transplant to treat a life-threatening blood cancer. The procedure carries significant risks and is highly complex.

The Toronto patient wishes to remain anonymous.

About University Health Network

UHN is Canada's Hospital — ranked #2 in the world, #1 in Canada. With 10 sites and more than 44,000 TeamUHN members, UHN consists of Toronto General Hospital, Toronto Western Hospital, Princess Margaret Cancer Centre, Toronto Rehabilitation Institute, The Michener Institute of Education and West Park Healthcare Centre. As Canada's top research hospital, the scope of biomedical research and complexity of cases at UHN have made it a national and international source for discovery, education and patient care. UHN has the largest hospital-based research program in Canada, with major research in neurosciences, cardiology, transplantation, oncology, surgical innovation, infectious diseases, genomic medicine and rehabilitation medicine. UHN is a research hospital affiliated with the University of Toronto.

About Unity Health Toronto

Unity Health Toronto is a leading Canadian health research institution with a wingspan across Toronto's core. Unity Health Toronto's strength lies in the combined expertise of its three hospital sites: St. Joseph's Health Centre, a community academic and acute care hospital supporting Toronto's west end; St. Michael's Hospital, a research-intensive academic health sciences centre affiliated with the University of Toronto with world-class specialty programs for complex cases; and Providence Healthcare, a campus of care for seniors, rehabilitation and long-term care. Our satellite clinics offer team-based primary care and community-based services. We aim to provide compassionate, high-quality care at every stage of our patients' health journey, from pediatric to primary care, urgent and acute care, world-class specialty care programs, seniors care, rehabilitation, long-term care, palliative care and advanced care for the most complex patients.

About the Toronto High Containment Facility at the University of Toronto

The Toronto High Containment Facility (THCF) provides secure, state-of-the-art laboratory infrastructure for research involving infectious pathogens requiring enhanced biosafety controls. Operating under stringent regulatory and safety standards, the THCF enables critical research in infectious disease, immunology, diagnostics and medical countermeasure development. The facility is a cornerstone of the Emerging and Pandemic Infections Consortium (EPIC), a University of Toronto Institutional Strategic Initiative that brings together U of T, The Hospital for Sick Children, Sinai Health, Sunnybrook Health Sciences Centre, Unity Health Toronto and University Health Network to drive innovative approaches to infectious diseases and build rapid response capacity to health emergencies.