Triple Therapy Completely Clears HIV in Newborn Primates

Researchers at Oregon Health & Science University found that a combination of three therapies — antiretrovirals, broadly neutralizing antibodies and the experimental antibody leronlimab — completely cleared HIV in newborn nonhuman primates treated within three days of exposure, even though none of the treatments worked alone. Published in Nature Microbiology, the result raises hopes for a one-time treatment that could eliminate HIV in newborns and, potentially, newly exposed adults.

Key Takeaways

Researchers at Oregon Health & Science University found that a combination of three therapies — antiretrovirals, broadly neutralizing antibodies and the experimental antibody leronlimab — completely cleared HIV in newborn nonhuman primates treated within three days of exposure, even though none of the treatments worked alone.
Published in Nature Microbiology, the result raises hopes for a one-time treatment that could eliminate HIV in newborns and, potentially, newly exposed adults.

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More than 120,000 babies worldwide acquire HIV every year, and millions of people live with the virus on lifelong treatment. A study led by Oregon Health & Science University (OHSU) points to a strikingly different possibility: a combination of three therapies, given to newborns within three days of exposure, permanently eliminated the virus in nonhuman primates.

Published in Nature Microbiology, the study found that none of the three treatments could clear the virus on its own — but together they did, in every case tested. "The really exciting part is that it could go to clinical trials immediately to eliminate HIV infection in newborns," said co-lead author Jonah Sacha, professor and chief of pathobiology and immunology at OHSU's Oregon National Primate Research Center. "The next step after that is to test if this can work in newly exposed adults."

The regimen combines standard antiretroviral therapy (ART), broadly neutralizing antibodies, and leronlimab, an experimental monoclonal antibody that blocks CCR5, a surface protein HIV commonly uses to enter immune cells. The researchers describe the three-pronged attack with analogies: ART turns off the faucet by minimizing viral replication; neutralizing antibodies mop up virus circulating in the blood; leronlimab seals off what remains from infecting immune cells.

"For reasons we don't understand, HIV really wants to use CCR5 receptors to infect cells," said Sacha. "By blocking access, it's like you've kept fuel away from the fire."

The treatment was only tested within 72 hours of infection, and the researchers now want to know how long that early window stays open. "We only tested out to three days," said Sacha. "Could it work a week after infection? Two weeks? How far can you go after infection, and still purge the virus?"

Nancy Haigwood, a veteran HIV antibody researcher and former ONPRC director, was "astounded and overjoyed" by the result. If human trials succeed, the strategy could eventually take aim at an epidemic that still kills about 600,000 people each year — starting with adults recently exposed to the virus.