This relative bioavailability (RBA) study will be conducted to investigate whether there is a potential pharmacokinetic effect when paediatric DT DTG (30 mg dose) and F/TAF TOS (180/22.5 mg dose) are taken together. For this purpose, Gilead's F/TAF 60/7.5 mg TOS tablets and ViiV Healthcare's DTG 5 mg tablets will be used. Given the very low plasma concentration of TAF (very probably mainly under the detection limit) with a single dose of 7.5 mg in adults, 3 tablets of F/TAF 60/7.5 mg (180/22.5 mg) will be given, which is similar to the adult dose. It was considered to keep the ratio between DTG and F/TAF similar to the to be developed paediatric fixed dose combination tablet, which would have resulted in a DTG dose of 60mg DTG DT. But because DTG shows nonlinear kinetics above a dose of 50 mg FCT (3), it was decided to use DTG 30 mg DT tablets, which is bioequivalent to adult dose of 50 mg FCT. For all compounds, a dose similar to the adult dose will be given.
This relative bioavailability (RBA) study will be conducted to investigate whether there is a potential pharmacokinetic effect when paediatric DTG and F/TAF are taken together as dispersible formulations. This study will be performed in healthy volunteers instead of HIV-infected patients.