This is a prospective observational study enrolling People Living with HIV (PLHIV) who are on a Dolutegravir-based AntiRetroviral Treatment (ART) regimen and experiencing virologic failure. Virologic failure is defined as two consecutive viral load measurements of >1000 copies/mL of blood. The main aim of the study is to identify the drug-resistance mutations in the viral genome that are associated with this failure.

To achieve this goal, patients fulfilling the eligibility criteria will be invited for a single study visit for the collection of blood. The extracted HIV virus will be sequenced through whole genome sequencing methods to identify the drug-resistance mutations. The study is conducted in 15-20 countries within six regions of the IeDEA cohort (International epidemiology Databases to Evaluate AIDS).

With the expansion of access to Anti-Retroviral Treatment (ART) in Low and Middle-Income Countries (LMIC), there is an increase in HIV drug resistance. The previously recommended 1st-line regimen of Tenofovir, Emtricitabine and Efavirenz (TEE) contains three drugs with a low genetic barrier to resistance. As a result, acquired drug resistance mutations are detected in the majority of people on TEE across different regions and HIV-1 subtypes. There has also been a steady increase in Pre-treatment Drug Resistance (PDR) as ART coverage has expanded in LMIC. WHO now recommends the use of Dolutegravir (DTG) in 1st -, 2nd and 3rd-line ART for adults and adolescents. Therefore, in most countries, PLHIV are transitioned to a DTG-based regimen. DTG is a potent Integrase Strand Transfer Inhibitor (InSTI) which has better efficacy and safety profile than Efavirenz in 1st-line therapy and Lopinavir/Ritonavir in 2nd-line therapy. DTG has a high genetic barrier to resistance, and resistance in ART-naïve individuals treated with combination ART has so far been rare. However, when used as monotherapy, or in people with pre-existing InSTI resistance, DTG is associated with a higher risk of virologic failure and resistance.

In this study, the investigators aim to -

1. Identify novel mutations or novel combinations of DTG Drug Resistance Mutations (DRMs).
2. Identify risk factors for virologic failure, development of InSTI DRMs and InSTI drug resistance.
3. Check the correlations between novel resistance genotypes and phenotypic DTG resistance across HIV-1 subtypes.

Adults (≥18 years) and adolescents (10-17 years) with virologic failure (viral load ≥1000 copies/mL) on any DTG-based anti-retroviral treatment (1st-line, 2nd-line and 3rd-line) at 20-30 clinical sites within six regions of the IeDEA cohort will be recruited into the study. There is only one study visit per participant and the study is observational and embedded in routine care, with no additional interventions. After obtaining informed consent, a blood specimen will be taken from the study participants. Whole genome sequencing will be performed using the Illumina MiSeq platform to identify the Drug Resistance Mutations. In addition, new DRMs and mutation pathways will be explored by viral genome-wide association study and conjunctive Bayesian network approaches.

Inclusion Criteria:

• Adults aged 18 years or older and adolescents (10-17 years)
• On any DTG-based ART regimen
• Who develop virologic failure (VF) defined as a VL >1000 copies/mL (single or confirmed measurement),
• and have signed the informed consent.

Exclusion Criteria:

• No Informed Consent

Patients routinely treated at the local HIV care clinics.

The Investigators are open to share any type of study data upon reasonable request, pending approval by local sites.

Within 1 year of study conclusion, for about 1 year.

Upon reasonable request, pending approval by local sites.