The authors were interested in the pharmacokinetics (PK), safety and tolerability of co-administered sofosbuvir/velpatasvir (SOF/VEL) for hepatitis C virus (HCV) with multiple commonly prescribed antiretroviral therapies (ART). They enrolled healthy volunteers into two phase 1, open-label, randomised, cross-over studies. SOF/VEL and ART regimens were administered alone and in combination; ART included atazanavir (ATV), cobicistat (COBI), darunavir (DRV), dolutegravir (DTG), efavirenz (EFV), elvitegravir (EVG), emtricitabine (FTC), lopinavir (LPV), raltegravir (RAL), rilpivirine (RPV), ritonavir (RTV), tenofovir alafenamide (TAF) and tenofovir disoproxil fumarate (TDF). The geometric least squares means (%GLSM) ratios (coadministration:alone) were calculated for AUCtau (area under plasma concentration-time curve over the dosing interval), Coax (maximum concentration) and Ctau (trough). 237 participants with 24-30 in each group were enrolled. The authors did not find any clinically relevant differences in the PK of SOF, SOF metabolite GS-331007 or VEL except for a ~50% decrease in VEL exposure when administered with EFV/FTC/TDF. In addition there were no clinically relevant differences in the PK of ART when administered with SOF/VEL. All study treatments were well-tolerated, including no observed changes to creatinine clearance during evaluation of TDF-containing regimens. Therefore SOF/VEL and ART regimens; including ATV, COBI, DRV, DTG, EVG, FTC, LPV, RAL, RPV, RTV, TAF or TDF; may be co-administered without dose adjustment. Use of SOF/VEL with EFV-containing regimens is not recommended due to the 50% reduction in VEL exposure.
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