CRF08_BC subtype is more prone to ART failure and new-generation NNRTI-resistance under long-term first-line ART

To investigate the characteristics of drug resistance mutations (DRMs) and their contextual influence on drug susceptibility in CRF07_BC and CRF_08BC subtypes.

Patients with virological failure were genotyped using phylogenetic analysis. DRMs and susceptibility to antiretroviral drugs were analysed using the Stanford University HIV Drug Resistance Database.

Six HIV subtypes were identified among 1296 successfully amplified sequences, with the CRF07_BC subtype prevailing at a rate of 91.7%, followed by CRF08_BC. Overall, the CRF07_BC and CRF08_BC subtypes were similar in the distribution and frequency of DRMs, the most common DRMs were K103N and M184V. However, among patients with antiretroviral therapy duration of ≥3 y who developed resistance, CRF08_BC exhibited a higher mutation frequency at sites 184, 138, 221, and 188 (Chi-square test, P < 0.05), and compared with CRF07_BC, patients with CRF08_BC had higher prevalence of abacavir, emtricitabine, lamivudine, doravirine, etravirine, and rilpivirine resistance. Moreover, there was an increased prevalence of cross-resistance between efavirenz/nevirapine and new-generation NNRTIs in patients with CRF08_BC; doravirine (r = 1.0), rilpivirine (r = 0.93), and etravirine (r = 0.86) resistance highly correlated with efavirenz/nevirapine.

The present study provides valuable insights into the profile of DRMs and resistance patterns in patients with CRF07_BC and CRF08_BC experiencing treatment failure in Butuo. These findings have the potential to contribute to future strategies for HIV control and treatment.