Phase 3 Study to Assess Viral Suppression Capability of 2-Drug ART Regimen

ViiV Healthcare recently announced that they will be launching a phase 3 study to ascertain if adults with HIV-1 who have achieved viral suppression on a 3-drug regimen consisting of tenofovir alafenamide fumarate (TAF) can maintain suppression when they are switched to a 2-drug regimen of dolutegravir and lamivudine.

Since the introduction of antiretroviral therapy (ART), an HIV diagnosis is no longer a death sentence. “The standard [ART] treatment consists of a combination of at least 3 drugs (often called ‘highly active antiretroviral therapy’ or HAART) that suppress HIV replication,” according to the World Health Organization. “Three drugs are used in order to reduce the likelihood of the virus developing resistance.”

Individuals infected with HIV require lifelong treatment. In order for the treatment to be effective, it is imperative for these individuals to adhere to their regimens. However, adherence can be difficult for several reasons, one of which being the medication dosing schedule. In addition to the challenge of adherence, there is also concern about the possibility of long-term toxicity created by exposure to antiviral agents over a lifetime of treatment. Long-term ART use has been associated with metabolic, cardiovascular, hepatic, renal, bone, bone marrow, and other complications or toxicities.

In their press release on the launch of the phase 3 trial, ViiV Healthcare states that the company is, “looking to the future and exploring how HIV treatment could evolve to reduce the number of drugs to which a patient is exposed while maintaining the level of efficacy achieved with 3-drug regimens.”

Dubbed the TANGO study, the trial aims to demonstrate the non-inferior antiviral activity of switching over to the 2-drug regimen compared with the continuation of a TAF-based (3-drug) regimen over the course of 48 weeks in virologically-suppressed subjects. TANGO will characterize the long-term antiviral activity, tolerability, and safety of the 2-drug regimen as well as patient satisfaction through 96 weeks.

“We are asking a simple question in the TANGO study—can virally-suppressed people with HIV reduce the number of medicines in their HIV treatment regimen while maintaining viral suppression?” Viiv Healthcare’s chief scientific and medical officer John C. Pottage, Jr, MD, said in the press release. “If the data show the answer to be yes, this may allow health care providers to address issues of long-term toxicity by reducing exposure to antiviral agents over a lifetime of treatment.”

“We believe that with its high barrier to resistance, dolutegravir has the right clinical profile to be a core part of [2-drug regimens] for the treatment of HIV-1 and look forward to seeing the results of TANGO in 2019,” he added.

This study comes on the heels of the GEMINI studies, which assessed the 2-drug regimen of dolutegravir and lamivudine in those with HIV-1 who were treatment-naïve. Results from these trials are expected to be announced later this year.