# Development of HIV Drug‐Resistance Mutations and Antiretroviral Efficacy Among Vietnamese Patients After Failure of 5‐Year First‐Line Therapy

## TL;DR

This study tracks how HIV drug resistance mutations develop in Vietnamese patients over five years of first-line treatment, showing increased resistance to key antiretroviral drugs.

## Contribution

The study provides new insights into the rapid emergence of HIV drug resistance mutations in a Vietnamese cohort over five years of first-line ART.

## Key findings

- After 5 years, PI resistance mutations increased from 2 to 14, with 13 new mutations emerging.
- Resistance mutations to NRTIs and NNRTIs also increased, with six novel mutations identified.
- HIV sensitivity to ART decreased significantly, especially for PIs, from 2.7% to 18.6%.

## Abstract

The emergence of drug‐resistant mutations in human immunodeficiency virus (HIV) over time presents a challenge to treatment. We describe the development of drug‐resistance mutations and ART efficacy reduction in Vietnamese patients with failure of first‐line ART during a 5‐year period.

This is a 5‐year observational cohort study with HIV viral loads of patients evaluated annually for 5 years (2017–2022) at the hospitals in Vietnam. Patients with a viral load ≥ 1000 copies/mL were subjected to identifying mutations in reverse transcriptase, protease, and integrase to evaluate HIV resistance and the efficacy of ART.

After 5 years of monitoring the HIV load of 2932 patients on ART, 75 (2.56%) patients had concurrent virological failure at all 5 years. In 2017, only 2/75 HIV strains possessed Protease Inhibitor (PI) resistance mutations, while 75/75 HIV strains had both Nucleoside Reverse Transcriptase Inhibitors (NRTIs) and Non‐Nucleoside Reverse Transcriptase Inhibitors (NNRTIs) resistance mutations. Only four PI resistance variants were found, while 40 and 32 mutations were resistant to NRTIs and NNRTIs. After 5 years, the number of HIV PI resistance mutations had increased to 14, with 13 new mutations emerging. There were six novel mutations associated with resistance to NRTIs, NNRTIs, and the proportion of preexisting mutations increased from 1.3% to 13.3%. Furthermore, HIV sensitivity to ART decreased from 2.7% to 18.6%.

After 5 years, HIV had increased resistance mutations to PIs, NRTIs, and NNRTIs, with PI resistance mutations increasing the most rapidly, and the decrease in HIV sensitivity to PIs was higher than that to NRTIs and NNRTIs.