Drug-drug interactions of simnotrelvir/ritonavir: an open-label, fixed-sequence, two-period clinical trial

• Published in: Clinical microbiology and infection Vol. 31; no. 1; pp. 101 - 107
• Main Authors: Ye, Pan-Pan, Yao, Bu-Fan, Yang, Yang, Yang, Xin-Mei, Li, Qian, Song, Lin-Lin, Chen, Ke-Guang, Zhou, Hai-Yan, Shi, Jin-Yi, Zhang, Ye-Hui, Zhao, Fu-Rong, Guo, Zi-jia, Xu, Shan-sen, Chen, Jia, Goh, Aik Han, Zhu, Shun-Wei, Zheng, Yi, Zhao, Wei
• Format: Journal Article
• Language: English
• Published: England Elsevier Ltd 01.01.2025
• Subjects: Adult; Antiviral Agents - adverse effects; Antiviral Agents - pharmacokinetics; ATP Binding Cassette Transporter, Subfamily B, Member 1 - antagonists & inhibitors; ATP Binding Cassette Transporter, Subfamily B, Member 1 - metabolism; COVID-19 Drug Treatment; Cytochrome P-450 CYP3A - metabolism; Cytochrome P-450 CYP3A Inhibitors - pharmacology; Drug Combinations; Drug Interactions; Drug-drug interaction; Female; Healthy subjects; Humans; Itraconazole - adverse effects; Itraconazole - pharmacology; Male; Midazolam - adverse effects; Midazolam - pharmacokinetics; Middle Aged; Pharmacokinetics; Rifampin - adverse effects; Ritonavir - adverse effects; Ritonavir - therapeutic use; Safety; Simnotrelvir; Young Adult; Simnotrelvir; Healthy subjects; Safety; Drug-drug interaction; Pharmacokinetics
• DOI: 10.1016/j.cmi.2024.09.007
• ISSN: 1198-743X; 1469-0691

Simnotrelvir is a small-molecule highly specific 3C-like protease inhibitor for anti-SARS-CoV-2 and was approved as a combination drug with ritonavir (simnotrelvir/ritonavir) in China. Simnotrelvir is a substrate of cytochrome P450 3A (CYP3A) and P-glycoprotein (P-gp), and a weak inhibitor of CYP3A. Ritonavir is a substrate and inhibitor of CYP3A and an inhibitor of P-gp. Hence, the drug-drug interaction potential of simnotrelvir/ritonavir should be investigated. This drug-drug interaction study was an open-label, fixed-sequence, two-period phase I clinical trial in Chinese healthy adult subjects, divided into three cohorts, including simnotrelvir/ritonavir co-administrated with a strong CYP3A and P-gp inhibitor (itraconazole) and inducer (rifampicin), and with a specific CYP3A substrate (midazolam). The results demonstrated that compared with administration of simnotrelvir/ritonavir alone, the co-administration with itraconazole increased the geometric least-square mean ratio (GMR) of the expose (area under the plasma concentration-time curve from time zero to the lowest detectable plasma concentration [AUC0-t]) of simnotrelvir by 25% (GMR 125%, 90% CI 114–137%), whereas co-administration with rifampicin significantly decreased the AUC0-t of simnotrelvir by 81.5% (GMR 18.5%, 90% CI 16.4–20.9%). Notably, simnotrelvir/ritonavir increased the AUC0-t of midazolam by 16.69-fold (GMR 1769%, 90% CI 1551–2018%). The co-administration of simnotrelvir/ritonavir and rifampicin caused the increased amount and severity of treatment-emergent adverse events, especially hepatotoxicity. The co-administration of simnotrelvir/ritonavir with CYP3A and P-gp inhibitors can be safely used, whereas the co-administration with CYP3A and P-gp strong inducer should be avoided to minimize the risk of under-exposure. Co-administration of midazolam with simnotrelvir/ritonavir increased systemic exposure of midazolam. ClinicalTrials.gov Identifier: NCT05665647. [Display omitted]