January 15, 2018HIV/AIDS
Antiretroviral therapy (ART) benefits the health of people living with HIV, prolongs their lives and prevents transmission of the virus to others. If taken daily as directed, ART can reduce viral load -- the amount of HIV in the blood -- to levels that are undetectable with standard tests. However, the virus remains dormant in a small number of immune cells, and people living with HIV must take ART daily to keep the virus suppressed. If a person with ART-suppressed HIV stops taking medication, viral load will almost invariably rebound to high levels. Studies are now underway to develop therapeutic strategies to induce sustained ART-free remission --the absence of viral rebound following discontinuation of ART. Clinical trials to assess the efficacy of such experimental therapies may require participants to temporarily stop taking ART, an approach known as analytical treatment interruption, or ATI.
According to an article published in PLOS Pathogens (11 January 2018), a short-term pause in HIV treatment during a carefully monitored clinical trial does not lead to lasting expansion of the HIV reservoir nor cause irreversible damage to the immune system. The study was designed to better understand the immunologic and virologic effects of ATI. For the study, blood samples were analyzed from 10 volunteers who had participated in a clinical trial evaluating whether infusions of a broadly neutralizing antibody could control HIV in the absence of ART. During the trial, participants temporarily stopped taking ART subsequently experienced viral rebound and resumed ART 22 to 115 days after stopping. While treatment was paused, the participants' HIV reservoirs expanded along with increases in viral load, and abnormalities in the participants' immune cells was observed. However, six to 12 months after the participants resumed ART, the size of the HIV reservoirs and the immune parameters returned to levels observed prior to ATI.
According to the authors, the findings support the use of ATI in clinical trials to evaluate the efficacy of therapeutic strategies aimed at achieving sustained ART-free remission. However, the authors added that larger studies that do not involve any interventional drugs are needed to confirm and expand on these results. The authors are currently conducting a clinical trial to monitor the impacts of short-term ATI on a variety of immunologic and virologic parameters in people living with HIV.