An HIV patient is in remission after a unique stem cell transplant. Why it could be a path to a cure

A German HIV patient who is in remission following a stem cell transplant from a donor with genes that are partially resistant to the disease is giving researchers new hope that more people could benefit from the treatment.

The first step in a stem cell transplant for people with cancer involves wiping out a patient's immune cells with chemotherapy.When patients also haveHIV, thesecells can be replaced with transplanted stem cells from rare individuals carrying genes that essentially make them immune to the virus that causes AIDS.Only a handful of people around the world are eligible for this procedure becausethey musthave both HIV and cancer.

According to a study presented by Christian Gaebler of Charit Berlin University's medical school the German HIV patient was treated for acute myeloid leukemia with a stem cell transplant in 2015. He stopped taking antiretroviral drugs in 2018 and the virus remains in remission. He's one of just seven people whowent intoremission from HIV between 2007 and 2023.

In mostof these cases, the stem cell donors naturally inherited two copies of the gene called CCR5 delta 32, which confers resistance to HIV.The German patientis the first case where the stem cell donorinherited just one copy of the CCR5 delta 32 gene, according toGaebler and his co-authors. The research is not yet peer reviewed.

Researchers hope Thursday's virtual announcement at the 25th International AIDS conference in Munich, Germany, could open the door totreatment being offered to more people and have promising implications for future HIV cure strategies.

"Hope is, to me, that a cure is possible, and that's what these cases demonstrate," Sharon Lewin, president of the International AIDS Society (IAS), told reporters.

But the reality, she noted, is that it's rare.

Case could help develop new treatments

Come September, the German HIV patient will have been in remission for six years, according to Gaebler, a length of time that gives the researchers confidence in what they're seeing.

"A healthy person has many wishes, a sick person only one," the anonymouspatient said in a statement from IAS on Thursday.

Dr. Marina Klein, a professor of medicine based at Montreal's McGill University, said the man's case could inform how new treatments are developed.

"This case shows that you don't actually need 100 per cent of your cells to be completely resistant," said Klein, who was not involved in the study.

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Research suggests that about 1 per cent of Caucasians were measured to have two copies of the resistance gene, while about 20 per cent have one copy.According to experts who studyHIV, in individuals with one copy of the gene, thevirus progresses slowly if they don't receive antiretroviral treatment, while those with two copies seemto be able to hold the virusat bay altogether.

Lewin, the IAS president, says the German patient's experience "suggests that we can broaden the donor pool for these kinds of cases."

Researchers also hope itcould have promising implications for future, more scalable HIV cure strategies.

Klein, who heads up a Canadian clinical trials network for HIV, noted that HIV diagnoses rose almost 25 per cent between 2021 and 2022. She says that makes it more difficult to reach the goal of eliminating the disease.

"People sometimes get impatient, but these incremental bits of learning really are what takes us to the path to cure ultimately," she said.

Questions about availability, cost-effectiveness

Eric Arts, a professor in microbiology and immunology at Western University, studies ways to control HIV.

Though he finds it encouraging that the patient no longer needs to take medications to control HIV, Artssays scaling up the approach so it can be used on other patients has its challenges.

"The actual solution that they're using to really treat leukemia in the first place is not a solution for HIV," Arts said. "To really deal with the [HIV] pandemic overall, it's got to be available to everyone."

When people with HIV take antiretroviral treatment, they're able to live a normal life, Arts said. For them, the low survival rate from a stem cell transplant and cost can't be justified, compared topeople with leukemia who have no other option.

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Rjean Thomas, and HIV specialist and the co-founder of the medical clinic l'Actuel, says people had less access to doctors during the pandemic, which may explain why there is an increase in the number of HIV cases.

As someone who lives with HIV, Jean-Paul Michael manages the disease with antiretrovirals.But when he was first diagnosed, he couldn't afford the medication.

He had beeninjecting crystal meth for years, but when he beganreceiving treatment for AIDS-related pneumonia in intensive careeight years ago, a housing stabilization worker offered himaffordable housing and tools to rebuild his life.

Stigma around HIV is still very prevalent, says Michael, noting thatthere's"a lot of recoil when people hear." He now works as an addiction case manager in the emergency department at St. Michael's Hospital in Toronto.

Both Michael and Klein called for antiretroviral medications to be accessible to everyone.

"If we could get to a point where we could actually teach the immune system to handle this virus in a way that didn't need medications it would be a major advance," Klein said.