Fast Five Quiz: Treatment-Resistant HIV

Michael Stuart Bronze, MD; Enrico Brunetti, MD


August 14, 2023

It is possible for individuals who have received preexposure prophylaxis (PrEP) to develop pretreatment drug resistance. Clinical scenarios in which this may occur include the initiation of PrEP among individuals with undiagnosed acute HIV; continued PrEP use by people who acquire HIV while using PrEP; and HIV infection of adherent PrEP users with viral strains that are resistant to PrEP ARV regimens ('breakthrough infections'). This could reduce HIV treatment options owing to the overlapping resistance profiles between ARV drugs used for both PrEP and the treatment of HIV. However, the potential for HIV drug resistance with PrEP is likely to be outweighed by the benefit of decreased HIV incidence with wider PrEP use.

Up to 10% of adults initiating HIV treatment can have drug resistance to the nonnucleoside reverse transcriptase inhibitor (NNRTI) drug class. By contrast, second-generation HIV integrase strand transfer inhibitors ([INSTIs], dolutegravir, bictegravir and cabotegravir) and newer-generation protease inhibitors (darunavir) have a high barrier to resistance.

The Joint United Nations Programme on HIV/AIDS has identified key population groups that are particularly vulnerable to HIV and often lack access to healthcare services. These include individuals who are transgender, gay men and other men who have sex with men, people who inject drugs, sex workers and the prisoner population. A recent systematic review found that pretreatment drug resistance exceeds 10% in several of these populations.

Recently, the WHO reported that the prevalence of pretreatment drug resistance to NNRTIs commonly used as first-line therapies in many countries was three times higher among ART initiators reporting previous ARV drug exposure (24%; 95% CI, 18%-29%) than among ART initiators naive to ARV drugs (7%; 95% CI, 4%-10%).

Learn more about HIV drug resistance.


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