Understanding drug resistance patterns across different classes of antiretrovirals used in HIV-1-infected treatment-Naïve and experienced patients in Mumbai, India.

Background: The aim of this study is to find out the proportion of treatment-naïve (Tn) and treatment-experienced (Te) patients experiencing HIV drug resistance (DR) to different classes of antiretrovirals (ARVs) being used for HIV treatment and their in class DR correlation.

Methods: A cross-sectional study was done on 109 HIV patients enrolled at a private hospital in Thane, India, from 2014 to 2019. All patients were tested for CD4 count, viral load, and resistance to ARVs.

Results: Sixty-six patients were Tn and 43 patients were Te. Among Tn and Te patients, the percentage of high-level resistance (HLR) for nonnucleoside reverse transcriptase inhibitors (NNRTI) was 4.55% and 37.8%, respectively, for nucleoside reverse transcriptase inhibitors (NRTI) was 0.43% and 36.4%, respectively. No HLR was observed for protease inhibitors (PIs) among Tn patients, while Te patients showed 2.62% HLR. Tn and Te patients showed high susceptibility for Darunavir (98.48% and 95.34%, respectively) followed by Atazanavir and Lopinavir (96.96%, each and 90.69%, each). Tn patients showed HLR for Lamivudine and Emtricitabine (1.52%, each). Integrase Strand Transfer Inhibitors were susceptible (100%) in both Tn and Te patients. A positive correlation was observed for within class across ARVs.

Conclusion: An increased incidence of HLR was observed for NNRTI as compared to NRTI while PIs and integrase strand transfer inhibitors (INSTIs) demonstrated no HLR in either group of patients. When selecting a regimen for Tn patients consisting of NRTIs + NNRTIs genotypic DR test is essential. While with PIs or INSTIs its optional. Among Te patients, DR testing is recommended for all classes of drugs.