No clinically meaningful pharmacokinetic interaction between the hepatitis C virus inhibitors elbasvir and grazoprevir and the oral contraceptives ethinyl estradiol and levonorgestrel.

PURPOSE: Oral contraceptive pills (OCPs) are an important element of hepatitis C virus (HCV) treatment in women of childbearing potential. These studies evaluated the safety and pharmacokinetic interactions between elbasvir (EBR) and grazoprevir (GZR) and ethinyl estradiol/levonorgestrel (EE/LNG).

METHODS: Both studies were open-label, single-site, two-period, fixed-sequence, one-way interaction studies. In period 1, subjects received one tablet of EE/LNG (0.03 mg/0.15 mg). In period 2, subjects received EBR (50 mg once daily) for 13 days or GZR (200 mg once daily) for 10 days, with one tablet of EE/LNG on day 7 (GZR group) or 10 (EBR group). Each study enrolled 20 healthy, nonsmoking adult females.

RESULTS: There was no clinically meaningful effect of multiple doses of EBR or GZR on the pharmacokinetics of EE or LNG. Geometric mean ratios (GMRs) for AUC0-∞ and Cmax in the presence and absence of EBR were 1.01 and 1.10 for EE and 1.14 and 1.02 for LNG, with 90% confidence intervals (CIs) that were contained in the interval [0.80, 1.25]. Similarly, the AUC0-∞ and Cmax GMRs in the presence and absence of GZR were 1.10 and 1.05 for EE and 1.23 and 0.93 for LNG, respectively. The 90% CIs for EE AUC0-∞ and for EE and LNG Cmax were contained in the interval [0.80, 1.25]; however, the 90% CI for the LNG AUC0-∞ [1.15, 1.32] slightly exceeded the upper bound.

CONCLUSIONS: These results suggest that EBR/GZR can be co-administered to female patients with HCV of childbearing potential who are on OCPs to prevent pregnancy.