ArticleClinical drug investigation2026
Effects of Ensitrelvir on the Pharmacokinetics of Combined Oral Contraceptives (Ethinyl Estradiol/Drospirenone) in Healthy Adult Women: A Phase 1 Fixed-Sequence, Multiple-Dose, Drug-Drug Interaction Study.
Article in Clinical drug investigation, 2026. The graph could read no effect estimate from its abstract, so it casts no vote on the map. It is linked to trial NCT06775730 (A Phase 1 Drug-Drug Interaction Study of S-217622 With Combined Oral Contraceptives in Healthy Adult Female Participants), which is not on this map. Not yet cited in PubMed.
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The abstract states no effect estimate the extractor could read, or names no intervention and outcome on the map, so this paper lights no cell and moves no belief. It is still indexed, cited and linked below.
The trial behind it
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A Phase 1 Drug-Drug Interaction Study of S-217622 With Combined Oral Contraceptives in Healthy Adult Female Participants
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Authors and funding
5 authors.
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No grant is acknowledged in the PubMed record.
Abstract
BACKGROUND AND
objectiveEnsitrelvir has shown cytochrome P450 3A (CYP3A) inhibitory/induction potential in in vitro studies. This open-label, fixed-sequence Phase 1 study evaluated potential drug-drug interactions between ensitrelvir and a combined oral contraceptive (COC) containing ethinyl estradiol (EE) and drospirenone in healthy women of childbearing age.
methodsHealthy premenopausal women received EE/drospirenone (0.02 mg/3 mg) on days 1-24. Ensitrelvir was co-administered on day 20 (375 mg) and days 21-24 (125 mg/day). Blood samples were collected on days 19, 20, and 24 to assess plasma EE, drospirenone, and ensitrelvir concentrations. The primary endpoint was evaluation of the maximum plasma concentration, time to maximum plasma concentration, and area under the plasma concentration-time curve over the dosing interval τ (AUC
resultsThe safety and pharmacokinetic parameter population comprised 24 and 23 participants, respectively. Compared with day 19, AUC
conclusionEnsitrelvir has no clinically meaningful effect on the pharmacokinetics of EE and drospirenone, and the combination was well tolerated. These findings support the co-administration of ensitrelvir with COCs in clinical practice.
trial registrationNCT06775730.
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