This is an interventional phase IV trial enrolling HIV-infected patients treated by dolutegravir or bictegravir-based combined antiretroviral therapy, and patients with a planned shift to a dolutegravir or bictegravir-based combined antiretroviral therapy, that aims at understanding the individual response to dolutegravir and bictegravir, in terms of efficacy and toxicity.

The main objective of our research project is to better define the inter-individual variability in terms of clinical and biological response towards Integrase Strand Transfer Inhibitors, an important ARV drug class used in the treatment of HIV infection. We aim at identifying predictors of drug efficacy and toxicity, which are eagerly awaited by clinicians as INSTIs are now prescribed worldwide and concerns about previously unidentified side effects are emerging.

The specific objectives of the project are:

• To study the impact of genetic polymorphisms in selected pharmacogenes (including genes coding for biotransformation enzymes and transport proteins) on INSTIs PK parameters and biomarkers relevant for TDM, such as trough (C0) and intracellular (IC) concentrations.
• To determine whether genetic polymorphisms in selected pharmacogenes might affect INSTIs efficacy, as assessed by the measurement of the viral load.
• To address the important question of the pathophysiological mechanisms lying behind the two main side effects of INSTIs, namely neuropsychiatric adverse events and abnormal weight gain.
• To describe how INSTIs affect the gut microbiome of treated patients, and to determine in turn how and by which pathways the gut microbiome might influence the clinical response (i.e. efficacy and toxicity) to INSTIs.

Inclusion will be proposed to:

• HIV infected adult patient regularly followed at Centre de reference HIV of CUSL and currently treated by 50mg OD of DTG (n=80) or 50mg OD of BIC (n=30).
• Virally controlled immunologically functional HIV infected adult patient regularly followed at Centre de reference HIV of CUSL and shifting from another ARV class to a treatment containing 50mg OD of DTG (n=20) or 50mg OD of BIC (n=20).
• HIV infected adult patient retrospectively identified as having stopped standard dosage of DTG (ie. 50mg OD) due to NPAE (insomnia, depression, anxiety) (n=50). Identification will be based on the interrogation of our prospective clinical database.

Exclusion Criteria:

• Pregnancy at the time of inclusion or expected pregnancy within 12 months, for patients treated by DTG or BIC during the study
• Liver failure (Child-Pugh A, B or C)

Subjects will be recruited among regularly HIV-infected patients regularly followed at the Centre de Prise en charge VIH of Cliniques universitaires Saint-Luc - UCLouvain