When Did HAART Become ART?

Understanding Combination HIV Therapy

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ART is the acronym commonly used today to describe HIV antiretroviral therapy. Previous to this, clinicians and scientist would use the term cART (combination antiretroviral therapy), and previous to that the popular term HAART was used to describe "highly active antiretroviral therapy."

The changes over the years reflect more than just fashion, but a real attempt by public health officials to re-frame how we communicate the efficacy of HIV therapy to the public.

No longer do we try to convince users that the drugs are "highly active" since they actually more than that. Today they allow for normal, quality of life, while newer one-pill options make the use of the word "combination" all the more redundant.

Understanding ART

Whatever the acronym used, the term implies the use of three or more antiretroviral drugs, either taken individually or in fixed dose combinations. The aim of therapy is to ensure the suppression of HIV to so-called "undetectable" levels—meaning that the virus is not fully eradicated, but is simply beneath detection levels of current testing assays.

As opposed to single-drug or dual-drug therapy, the combination of three or more active drugs is known to effectively suppress the variety of resistant HIV that can exist within a viral population. Essentially, if one drug is unable to suppress a certain viral mutation, the others will likely be able to do so.

High levels of adherence are needed in order to maintain therapeutic drug levels in the blood. If these levels fall beneath the therapeutic threshold, resistant strains are provided an opportunity to thrive. The larger these resistant populations, the less effective the drugs will be in suppressing HIV replication—eventually leading to viral rebound and treatment failure.

Since 2009, the term cART largely supplanted the more commonly known HAART, particularly among researchers and clinicians. While the terms are essentially interchangeable, HAART was largely considered inadequate in describing the empirical effectiveness of combination therapy.

Subsequently, ART was considered more appropriate, given the likelihood that combination therapy will change in coming years. Current research is investigating the use of two rather than three antiretroviral drugs, such as ripilvirine and dolutegravir, in the management of chronic HIV infections.

Classes of ART

There are currently five classes of antiretroviral drug, each of which inhibit a specific stage in the HIV life cycle:

Other classes of antiretrovirals are being investigated, while newer-generation drugs aim to improve tolerability, reduce adverse effects and simplify dosing for those on therapy.

To this end, an increasing number of fixed dose combination (FDC) drugs are now available, combining two or more drug into a single pill or tablet. Some, including Atripla ((tenofovir + emtricitabine + efavirenz), Triumeq (abacavir + lamivudine + dolutegravir) and Stribild (tenofovir + emtricitabine + elvitegravir + cobicistat) offer all-on-one formulations for simplified, daily dosing.

Future of ART

With advances in HIV drug developments, ART is now being employed as a means to reverse infection rates in high prevalence HIV populations.The strategy, known as Treatment as Prevention (TasP), has been shown to reduce the risk of transmitting HIV by suppressing viral activity to undetectable levels. In doing so, the risk of transmission is reduced by as much as 96%.

By ensuring widespread drug distribution, ART can lower the so-called "community viral load" (the median viral load within a community) to levels where the likelihood of transmission is significantly, even profoundly, reduced.

Scientists are now exploring the development of long-lasting antiretroviral agents, some of which may require monthly or even quarterly drug dosing.

Sources:

Delaney, M. "History of HAART – the true story of how effective multi-drug therapy was developed for treatment of HIV disease." Retrovirology. December 21, 2006; 3(Suppl 1): S6.

Skarbinski, J.; Furlow-Parmley, C.; and Frazie, E. "Nationally Representative Estimates of the Number of HIV+ Adults who Received Medical Care, Were Prescribed ART, and Achieved Viral Suppression-Medical Monitoring Project, 2009 to 2010-US." 19th Conference on Retroviruses and Opportunistic Infections (CROI); Seattle, Washington; March 8, 2013; oral abstract #138.

Spreen, W; Margolis, D.; and Pottage, J.;"Long-acting injectable antiretrovirals for HIV treatment and prevention." Current Opinions on HIV and AIDS. November 2013; 8(6):565-571.

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