Dolutegravir Has No Effect on the Pharmacokinetics of Oral Contraceptives With Norgestimate and Ethinyl Estradiol

Background: Dolutegravir (DTG; Tivicay; ViiV Healthcare, Research Triangle Park, NC) is an HIV-1-unboosted integrase inhibitor with no cytochrome P450 or uridine 5′diphosphate-glucuronosyltransferase inhibition or induction. As DTG is administered to HIV-1–infected women receiving oral contraceptives, assessing the potential for drug interactions was warranted. Objective: To determine the impact of DTG on the pharmacokinetics (PK) and pharmacodynamics (PD) of a common oral contraceptive, norgestimate/ethinyl estradiol (NGM/EE; Ortho-Cyclen; Ortho-McNeil-Janssen Pharmaceuticals, Inc, Raritan, NJ). Methods: This randomized, 2-period, double-blind, placebo-controlled study was conducted within 1 menstrual cycle at 1 clinical center in the United States; 16 women were enrolled. Participants received NGM 0.25 mg/EE 0.035 mg throughout the study. During days 1 to 10, they were randomized to receive twice-daily DTG 50 mg or matching placebo with food and switched to the other treatment during days 12 to 21. Results: Ratios of area under the concentration-time curve from time 0 until end of the dosage interval (AUC(0-τ)), maximum plasma concentration, and concentration at the end of the dosage interval of norelgestromin with DTG treatment to the same PK parameters with placebo treatment were 0.975, 0.890, and 0.932, respectively; for EE, ratios were 1.03, 0.99, and 1.02, respectively. No significant differences in luteinizing hormone, follicle-stimulating hormone, and progesterone were detected on days 1, 10, 11, 21, and 22. DTG steady-state AUC(0-τ) was similar to historical data. No severe or grade 3/4 adverse events occurred. Conclusions: DTG had no effect on NGM/EE PK or PD. NGM/EE can be administered with DTG without dose adjustment.