Background: Doravirine (DOR) is a novel non-nucleoside reverse transcriptase inhibitor available as a single tablet and a three-drug combination with lamivudine (3TC) and tenofovir disoproxil fumarate (TDF) to treat HIV-1 infection. These analyses assessed pharmacokinetic (PK) interactions with coadministration.
Methods: Two trials were conducted. Study 1: two-period, fixed-sequence; eight healthy participants; Period 1, DOR 100 mg followed by ≥7-day washout; Period 2, TDF 300 mg once daily for 18 days, coadministration of DOR 100 mg on day 14. Study 2: three-period, crossover, 15 healthy participants; Treatment A, DOR 100 mg; Treatment B, 3TC 300 mg + TDF 300 mg; Treatment C, DOR 100 mg + 3TC 300 mg + TDF 300 mg; ≥7-day washout between periods.
Results: Study 1: geometric mean ratios (GMRs; 90% confidence interval [CI]) of DOR area under the concentration-time curve from time 0 extrapolated to infinity (AUC0-∞) and observed plasma concentrations at 24 h post-dose (C24 h; DOR+TDF/DOR) were 0.95 (0.80, 1.12) and 0.94 (0.78, 1.12), respectively. Study 2: GMRs (90% CI) of DOR AUC0-∞ and C24 h (DOR+3TC+TDF/DOR) were 0.96 (0.87, 1.06) and 0.94 (0.83, 1.06), respectively. GMRs (90% CI) of 3TC and tenofovir AUC0-∞ (DOR+3TC+TDF/3TC+TDF) were 0.94 (0.88, 1.00) and 1.11 (0.97, 1.28), respectively. Study drugs were generally well tolerated.
Conclusions: Multiple doses of TDF did not have a clinically meaningful effect on DOR PK. The PK of DOR were similar when administered alone or in combination with 3TC and TDF. DOR had no meaningful effect on the PK of 3TC and tenofovir.