Abstract
BACKGROUND: Two large studies suggest that resistance mutations to only nonnucleoside reverse transcriptase inhibitors (NNRTI) did not increase the risk of virologic failure during antiretroviral therapy (ART) with efavirenz/tenofovir disoproxil fumarate/lamivudine (or emtricitabine). We retrospectively evaluated a third cohort to determine the impact of NNRTI resistance on the efficacy of efavirenz-based ART. METHODS: Postpartum women living with human immunodeficiency virus (HIV) were studied if they initiated efavirenz-based ART because of the World Health Organization's recommendation for universal ART. Resistance was detected by Sanger genotyping plasma prior to efavirenz-based ART and at virologic failure (HIV RNA >400 copies/mL). Logistic regression examined relationships between pre-efavirenz genotypes and virologic failure. RESULTS: Pre-efavirenz resistance was detected in 169 of 1223 (13.8%) participants. By month 12 of efavirenz-based ART, 189 of 1233 (15.3%) participants had virologic failure. Rates of virologic failure did not differ by pre-efavirenz NNRTI resistance. However, while pre-efavirenz nucleos(t)ide reverse transcriptase inhibitors (NRTI) and NNRTI resistance was rare (8/1223 [0.7%]) this genotype increased the odds (adjusted odds ratio, 11.2 [95% confidence interval, 2.21-72.2]) of virologic failure during efavirenz-based ART. Age, time interval between last viremic visit and efavirenz initiation, clinical site, viremia at delivery, hepatitis B virus coinfection, and antepartum regimen were also associated with virologic failure. CONCLUSIONS: Resistance to NNRTI alone was prevalent and dual-class (NRTI and NNRTI) resistance was rare in this cohort, with only the latter associated with virologic failure. This confirms others' findings that, if needed, efavirenz-based ART offers most people an effective alternative to dolutegravir-based ART.