Lack of a Clinically Important Pharmacokinetic Interaction Between Sofosbuvir or Ledipasvir and Hormonal Oral Contraceptives Norgestimate/Ethinyl Estradiol in HCV-Uninfected Female Subjects

This study evaluated the potential for a drug-drug interaction between HCV direct-acting antivirals sofosbuvir or ledipasvir and oral hormonal contraceptive (OC) norgestimate/ethinyl estradiol (norgestimate 0.18/0.215/0.25 mg with ethinyl estradiol 25 g). This was a 112-day, open-label, fixed-sequence pharmacokinetic (PK) study in healthy female subjects that included a lead-in cycle (OC only; N = 21), cycle 1 (OC only; N = 15), cycle 2 (OC + sofosbuvir; N = 15), and cycle 3 (OC + ledipasvir; N = 15). Administration of sofosbuvir with OC did not alter PK of norelgestromin (primary norgestimate metabolite) or ethinyl estradiol. Small increases in norgestrel (secondary norgestimate metabolite) AUC(tau) (19%) and C-tau (23%) with sofosbuvir were noted. Ledipasvir did not impact PK of norelgestromin or norgestrel but modestly increased ethinyl estradiol C-max (40%). Sofosbuvir, GS- 331007 (predominant circulating metabolite of SOF), and ledipasvir PK were similar to historical data. Pharmacodynamic markers luteinizing hormone, follicle-stimulating hormone, and progesterone values were generally comparable in all cycles. No loss in contraceptive efficacy is expected upon administration of sofosbuvir or ledipasvir/sofosbuvir with oral contraceptives containing norgestimate and ethinyl estradiol. The use of sofosbuvir or ledipasvir/sofosbuvir FDC with oral contraceptives is permitted.