BACKGROUND: Because of progress in antiretroviral therapy (ART), fewer people with HIV experience virologic failure with multiclass resistance. We sought to estimate the prevalence of multiclass resistance since the introduction of INSTI-based regimens using a systematic literature review.
METHODS: A systematic literature search using PubMed, Embase, and the Cochrane Library was conducted of articles published since 2008, the year when INSTI-based regimens for treatment-experienced people with HIV became widely used. Bibliographies of existing literature reviews, websites of European and International organizations reporting data on HIV and AIDS, and abstracts presented from 2016–2018 at conferences were searched to identify additional relevant studies. Using predefined criteria, two reviewers independently reviewed studies reporting multiclass (three-class or greater) resistance in persons with HIV infection who are treatment experienced and were either perinatally infected or infected as adults. Studies from Western Europe, Australia, Canada and the United States (US) using any type of resistance definitions and resistance tests were included.
RESULTS: A total of 441 unique articles were identified, 343 were excluded during level 1 screening and 98 articles were included for full-text review. A total of 34 articles (11 US studies, 3 from Canada, 1 from Australia, and 19 from Western European countries.) met the inclusion criteria and were included in data extraction analysis. Over the past decade, a modest decrease in the prevalence of three-class (NNRTI, NRTI, PI) resistance was observed in studies from the United States and Canada, ranging from 8.3% in 2009 to 6.7% in 2014 (Figure 1). Western European countries and Australia showed similar trends. The prevalence of 4-class resistance (including INSTIs) with virologic failure in the current treatment era is low, less than 2% (Figure 2).
CONCLUSION: The prevalence of multiclass resistance has decreased over the past decade, with three-class resistance continuing to decline and four-class resistance rare. Although the population with treatment failure and no viable options for a suppressive regimen is currently small, this group of people with HIV are in urgent need of novel treatment options.