- Brendan Smialowski/AFP/GettyImages
- Scientists say they may have cured a man of HIV by performing a stem-cell transplant to treat his cancer.
- Only one other person is thought to have been cured of HIV. He’s also a man with cancer who got a stem-cell transplant.
- HIV/AIDS researchers say this is an exciting development – but it’s also a risky strategy, perhaps even life-threatening.
First there was one; now there are two. A second person with cancer had a bone-marrow transplant that looks as if it cured him of HIV.
The first person thought to be cured of HIV, the virus that causes AIDS, was an American man named Timothy Brown, previously known as “the Berlin patient,” who received a bone-marrow transplant in 2007 to help treat his aggressive leukemia. The second person who may have been cured has Hodgkin’s lymphoma and lives in the UK.
“It’s cool because before this we had an n of one,” Jeffrey Milush, a microbiologist who directs the UCSF Core Immunology Laboratory and was not involved in the latest research, told Business Insider. “Now we’ve got two people.”
But the scientists behind the case are still approaching it cautiously.
“At 18 months post-treatment interruption it is premature to conclude that this patient has been cured,” they wrote in the journal Nature on Tuesday. But essentially, they think that’s what they’ve done.
In both cases, the patients weren’t trying to cure their HIV – they were dealing with aggressive forms of cancer, and their oncologists recommended bone-marrow transplants to treat it.
The reason these specific bone-marrow transplants seem to be capable of curing HIV is that both donors had a genetic mutation in a protein called CCR5 that made them more resistant to a common kind of HIV, the kind both men had.
“It does give them some superpower, in the sense of being protected from CCR5-using HIV,” Milush said.
But even though Brown is thought to be cured of that strain, he still has to take medications that prevent another strain that uses the CXCR4 protein from replicating in his body.
“They’re not impervious to infection,” Milush said. “They are just more resistant to the major type of HIV.”
What these cases mean for the future of HIV/AIDS treatment
- Phalinn Ooi/flickr
These types of stem-cell transplants require harvesting blood marrow from a compatible human donor, wiping out the patient’s own immune system, then reconstituting it with the donated marrow. The patient has to take potent drugs that help their body accept the donor’s immune system.
It’s an expensive, invasive, and extremely complicated immunological dance, and bone-marrow transplants can be fatal.
“It’s not simple,” Milush said.
It’s also not a realistic treatment option for most people with HIV, who don’t necessarily have cancer. More than 38,000 Americans were diagnosed with HIV last year, and 6,160 deaths in the US in 2016 were directly attributed to HIV. Public health experts have a bullish plan to end HIV in the US by 2030, but it does not involve expensive and dangerous bone-marrow transplants.
“You’ve gotten millions upon millions of people infected with HIV, and you certainly aren’t going to be doing stem-cell transplants on all of them,” Milush said. “We need something that’s going to be able to be rolled out to the mass population. If we focus only on these bone-marrow transplants, I think we’re going to miss the opportunity to treat the widest group of people.”
The most promising way to end HIV in the US, experts say, is to manage a patient’s virus with drugs and prevent it from spreading to more people.
“We have very effective antiretroviral therapy, and when people are on retroviral therapy and achieve an undetectable viral level, they cannot transmit the disease,” Brett Giroir, the assistant secretary for health at the Department of Health and Human Services, told reporters in February.
Though various drugs on the market can make it easier to live with HIV, it is still a dangerous condition if not treated well. And while these drug cocktails are good at controlling the virus, they don’t eradicate it.
So scientists like Milush are still on the hunt for a full-on HIV cure for all. Some of the most promising strategies include extracting and genetically transforming a patient’s own virus cells (sometimes with the Crispr gene-editing technique), or a vaccine.
The new case could also help scientists by informing research into cures that would be less dangerous than bone-marrow transplants.
“Continuing our research, we need to understand if we could knock out this [CCR5] receptor in people with HIV, which may be possible with gene therapy,” Ravindra Gupta, the study’s lead author, said in a release.