SLCO3A1 expression is a major determinant of atazanavir PBMC penetration in HIV-infected patients

Background Atazanavir (ATV) is administered at a dose of 300 mg boosted with 100 mg of ritonavir once daily (boosted). However, in the clinical setting use of unboosted ATV can be warranted. Although plasma concentrations are used clinically as a marker of drug exposure, ATV predominantly acts within HIV infected cells and therefore intracellular concentrations may better correlate with therapeutic efficacy. To date, the factors that define ATV flux into peripheral blood mononuclear cells (PBMC) are not fully characterized and several efflux and influx transporters may influence intracellular pharmacokinetics.