Levels of Adherence Required for Virologic Suppression Among Newer Antiretroviral Medications

Abstract

To determine the adherence levels needed for HIV virologic suppression with newer antiretroviral (ARV) medications, including darunavir, etravirine, and raltegravir. Literature searches of PubMed, MEDLINE (1950-October 2010), and Google Scholar were performed using the following key words in multiple combinations: antiretroviral, HIV, AIDS, adherence, darunavir, raltegravir, and etravirine. A review of the bibliographies of retrieved articles was performed to identify additional references. All articles in English were identified from the data sources and evaluated. Studies that did not state names of medications or drug classes studied were excluded. There are differing levels of adherence needed to maintain virologic suppression, depending on the ARV class used. The adherence level needed for unboosted protease inhibitors (PIs) has been established as greater than 95%, but recent studies have shown that greater than 80% adherence to boosted PIs may be sufficient. Nonnucleoside reverse transcriptase inhibitors (NNRTIs) could require lower adherence rates than boosted PIs; however, study results are varied and NNRTIs carry a potential for developing resistance with nonadherence. Studies assessing the adherence needed for raltegravir have yet to be performed. Studies have shown differing levels of adherence needed among ARV classes of medications. With the advent of boosted PIs and potent medications, the amount of adherence needed has dropped since the 1990s. Although the current data are useful, there are discrepancies in the results due to the methods of adherence measurement. Knowing what adherence levels are needed is valuable in helping to determine the optimal ARV regimen for patients, given their adherence barriers. This knowledge can also help determine which patients require in-depth adherence counseling. Further research with a reliable method of measuring adherence is essential to determine adherence levels needed for newer ARV medications, including darunavir, etravirine, and raltegravir.