Around 120,000 children worldwide are diagnosed with HIV each year, who typically acquire it from their mothers during pregnancy, childbirth, or breastfeeding.
Certain treatments can prevent HIV from progressing to acquired immunodeficiency syndrome (AIDS). However, they do not eliminate the virus completely, so it can return if treatment stops.
As researchers continue searching for ways to prevent or cure HIV, scientists involved in a new study tested a combination of treatments in primates.
They found that starting a three-part treatment within 3 days of exposure may stop a similar virus from becoming permanently established.
The study is published in Nature Microbiology.
The World Health Organization (WHO) describes HIV as “a virus that attacks the body’s immune system.” Without treatment, HIV can progress to AIDS.
HIV-related deaths have declined over the years, and improvements in treatments such as antiretroviral therapy (ART) have contributed to this.
While ART can suppress HIV and stop it from turning into AIDS, it does not eliminate the hidden reservoirs of the virus. These reservoirs allow the virus to remain inactive in the body and begin multiplying again if treatment stops.
The researchers studied 55 male and female infant rhesus macaques. When the monkeys were around 1 month old, the scientists exposed them to simian-human immunodeficiency virus (SHIV), a virus that causes illness similar to AIDS.
The team compared seven treatment approaches aimed at preventing the virus from forming permanent reservoirs.
The approaches included ART, two broadly neutralizing antibodies (bNAbs), and leronlimab, an experimental monoclonal antibody. The researchers tested the therapies individually and in different combinations.
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For the final experiment, they gave eight of the monkeys all three therapies at 72 hours after being exposed to SHIV. At this point, the researchers could already detect the virus in the macaques’ blood.
The monkeys received one dose of two bNAbs, 9 weekly doses of leronlimab, and daily ART for 27 weeks.
After treatment ended, the researchers monitored the monkeys to see whether the virus returned. They later depleted the animals’ CD8 T cells to make sure the virus was truly gone rather than being hidden or controlled by the immune system.
The study authors noted that previous research using ART alone or ART combined with bNAbs did not consistently prevent the virus from returning.
The researchers saw similar results in this study. The individual and two-part treatments lowered virus levels, but it eventually returned.
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The outcome was different when the researchers combined all three treatments.
All eight macaques in the triple-treatment group had detectable virus when they began receivingART, bNAbs, and leronlimab. Not only did the treatment suppress the virus, but it also did not return after the researchers stopped ART at week 27.
Over 6 months of follow-up, the researchers found no viral DNA in the monkeys’ blood. When they later depleted the animals’ CD8 T cells, they still detected no viral rebound.
At 84 weeks after exposure, the scientists still found no detectable SHIV in the tissue samples. While they cannot yet say whether the treatment will work in human newborns, the findings offer hope that HIV detected and treated shortly after infection could potentially be cleared.
Jagdish Khubchandani, PhD, MPH, a public health professor at New Mexico State University, who was not involved in this research, told Medical News Today that he was excited about the study results, but said he remains “cautiously optimistic.”
“This is a multipronged approach that makes a lot of biological sense,” Khubchandani said, explaining that the therapies target different stages of early infection.
Khubchandani said the use of primates made him more optimistic about the results. He pointed out that primates “mirror our biology in numerous ways, have a history of testing for HIV, and what we know from primates about HIV has been highly valuable so far.”
However, Khubchandani said applying the findings to human newborns could prove difficult and that clinicians would need to identify babies who acquired HIV and begin treatment shortly after birth.
He noted that the researchers must also determine the appropriate dose, whether the treatment works when started beyond three days after exposure, and whether it is safe and effective in human newborns.
Jagmohan Batra, MD, a pediatric infectious disease specialist and medical director of Bickerstaff Family Center at Miller Children’s and Women’s Hospital Long Beach, likewise not involved in the study, also spoke with MNT. Batra said the findings are “very important.”
“A single therapy may control viral replication or decrease the reservoir but does not seem to eliminate it,” said Batra. He noted that by targeting HIV in three different ways, the combination may have a better chance of preventing a permanent viral reservoir from forming.
Batra said the primate findings make it plausible that the treatment could also work in human newborns. However, he said that determining when a baby acquires HIV could complicate things.
“The longer the infection persists, there are likely more reservoirs established and in more tissue types,” he explained.
Batra said the approach might initially be most useful for babies at high risk of acquiring HIV during delivery while clinicians await their birth test results.
