There is still no cure for HIV infection and the extensive viral genetic diversity represents the one of the biggest obstacles to develop an effective therapy. Our previous results reinforced the importance of understanding the dynamics of HIV-1 subtype expansion and monitoring DRMs prevalence to establish specific guidelines for prevention and treatment in a specific populational group. Within this project, we aim at further investigating the prevalence of DRMs in ART-failing patients in the recent years in prevalent HIV-1 subtypes, to understand the impact of the current changes in treatment guidelines. Overall, this work could provide valuable insights about HIV-1 subtype C genetic diversity and its impact on the HIV-1 infection dynamics.