Could HIV One Day be Controlled After Stopping Antiretroviral Therapy?

A new study led by scientists Tae-Wook Chun and Anthony Fauci looks more closely at how HIV might be controlled after stopping antiretroviral therapy.

Chun and Fauci, both with the National Institute of Allergy and Infectious Diseases (NIAID), led research that "has identified two distinct ways that people with HIV can control the virus for an extended period after stopping antiretroviral therapy (ART) under medical supervision," a National Institutes of Health news release detailed.

"This information could inform efforts to develop new tools to help people with HIV put the virus into remission without taking lifelong medication, which can have long-term side-effects," the release noted.

The study was published Oct. 29 in the journal Nature Medicine and centered on "two adults with HIV who began ART soon after acquiring the virus and continued with treatment for more than six years, successfully suppressing HIV.

"The individuals then joined an HIV clinical trial and stopped taking ART under medical supervision," the news release detailed. "The study team followed one of these people for four years and the other for more than five years, with study visits roughly every two to three weeks."

In one case, the study participant experienced "intermittent rebounds" of the virus over a period of about three and a half years, the release said. That individual then "began taking suboptimal ART without telling the study team," though blood tests revealed he had restarted a drug regime.

The other study participant "almost completely suppressed HIV for nearly four years, at which point the virus rebounded dramatically because he became infected with a different HIV strain, a phenomenon known as "superinfection,' " the study went on to say.

New Scientist covered the study, explaining that "different immune mechanisms seemed to be responsible in each case.

"There are two main arms of the immune system: antibodies and T-cells," the article went on to clarify. "Until now, it was thought that T-cells, which directly kill virus-infected human cells, were more important for post-treatment controllers.

"But Chun and his colleagues found that while T-cells were responsible in one man, antibodies were suppressing virus multiplication in the other. 'He had an amazing antibody response that probably completely contained viral replication,' says Chun."

The phenomenon of so-called "HIV controllers" has been observed and studied for some time. An estimated 1% of people living with HIV are thought to be able to suspend their ART regimens for extended periods and maintain a low viral load.

A 2015 Physicians Weekly story covered the subject, saying that controllers "have been thought to hold clues on how to develop a vaccine against HIV because of their unique immune responses."

Part of that response may be related to patients going on effective HIV regimens promptly, rather than waiting to do so, New Scientist noted, saying that the ability of controllers to suspend their drug regimen after a period of time and keep a low viral load for years at a time may be "because the virus doesn't have a chance to become established in so many of their immune cells."

"Understanding the underlying processes could help researchers determine which immune responses should be boosted in non-controllers so that their stronger defenses could hold the line against HIV without ART in the same way these processes happen in controllers," the Physicians Weekly article quoted Dr. Richard T. D'Aquila as saying.

While ongoing research holds the potential of eventually helping unlock new therapies, it also helps underscore the importance of HIV testing and timely ART intervention.