Findings Support Pausing ART for Research Purposes

A new study provides empirical evidence for what HIV researchers have long observed anecdotally: that it’s safe to temporarily stop antiretroviral therapies (ART) in controlled settings for the purposes of evaluating new HIV therapies.

Anthony S. Fauci, MD, director of the National Institute of Allergy and Infectious Diseases (NIAID), which conducted the study, said researchers wanted to know if temporary cessation of ART, known as analytical treatment interruption (ATI), had any impact on ART’s effectiveness upon resumption, or caused any other measurable harms.

NIAID, part of the National Institutes of Health (NIH), enrolled 10 participants in the study, each of whom stopped ART for between 22—115 days.

“We found out that when you temporarily, in a controlled way, interrupt therapy to the point where the virus rebounds and then put them back on drugs, every single person responds as well as if they were never off the drug,” Fauci told MD Magazine.

During the time they were off ART, the 10 patients experienced expanded HIV reservoirs and increased viral loads, allowing researchers to note abnormalities in the patients’ immune cells. However, all of those data points reverted to pre-cessation levels within 6—12 months of resumption of ART, the investigators reported, and no permanent immune system damage was noted.

One other notable finding, Fauci said, was that some people don’t experience a viral rebound for weeks or months after stopping ART. That’s a significant deviation from what had once been the norm.

Fauci said decades ago, people would experience viral rebound within 7—14 days after cessation of ART.

“Today, with the newer regimens, sometimes people go months to a year without rebounding,” he said.

That’s the reason that among the 10 participants in the study, 1 patient needed to resume therapy within 3 weeks, while another lasted nearly 4 months before a viral rebound was observed and treatment resumed.

Fauci said his agency is currently in the midst of a larger study that he hopes will confirm the findings. That study will look at the impacts of ATI on a broader range of immunologic and virologic parameters.

Asked if the findings will make it easier to enroll patients in HIV studies, Fauci said finding study participants generally hasn’t been a problem.

“We have patients that are very, very willing to participate in experimental studies, as long as they know what the rationale of the study is,” he said.

One reason those studies are important is that, despite its life-changing impact on people living with HIV, ART still has a major drawback.

“ART is working extremely well, but there are a certain subset of people who get pill fatigue and don’t want to be on ART the rest of their lives,” he said.

He said the new research will make it easier to study ways to achieve ART-free remission, where suppression of viral loads is sustained even after ART is stopped.

The study is titled, “Effect of analytical treatment interruption and reinitiation of antiretroviral therapy on HIV reservoirs and immunologic parameters in infected individuals" and was published January 11 in PLOS Pathogens.

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