Survey of Pharmaceutical Industry’s Best Practices around In Vitro Transporter Assessment and Implications for Drug Development: Considerations from the International Consortium for Innovation and Quality for Pharmaceutical Development Transporter Working Group

Helen E. Rollison; Pallabi Mitra; Hugues Chanteux; Zhizhou Fang; Xiaomin Liang; Seong Hee Park; Chester Costales; Imad Hanna; Nilay Thakkar; James M. Vergis; Daniel A.J. Bow; Kathleen M. Hillgren; Jochen Brumm; Xiaoyan Chu; Cornelis E.C.A. Hop; Yurong Lai; Cindy Yanfei Li; Kelly M. Mahar; Laurent Salphati; Rucha Sane; Hong Shen; Kunal Taskar; Mitchell Taub; Kimio Tohyama; Christine Xu; Katherine S. Fenner

doi:10.1124/dmd.123.001587

Abstract

The International Consortium for Innovation and Quality in Pharmaceutical Development Transporter Working Group had a rare opportunity to analyze a crosspharma collation of in vitro data and assay methods for the evaluation of drug transporter substrate and inhibitor potential. Experiments were generally performed in accordance with regulatory guidelines. Discrepancies, such as not considering the impact of preincubation for inhibition and free or measured in vitro drug concentrations, may be due to the retrospective nature of the dataset and analysis. Lipophilicity was a frequent indicator of crosstransport inhibition (P-gp, BCRP, OATP1B, and OCT1), with high molecular weight (MW ≥500 Da) also common for OATP1B and BCRP inhibitors. A high level of overlap in in vitro inhibition across transporters was identified for BCRP, OATP1B1, and MATE1, suggesting that prediction of DDIs for these transporters will be common. In contrast, inhibition of OAT1 did not coincide with inhibition of any other transporter. Neutrals, bases, and compounds with intermediate–high lipophilicity tended to be P-gp and/or BCRP substrates, whereas compounds with MW <500 Da tended to be OAT3 substrates. Interestingly, the majority of in vitro inhibitors were not reported to be followed up with a clinical study by the submitting company, whereas those compounds identified as substrates generally were. Approaches to metabolite testing were generally found to be similar to parent testing, with metabolites generally being equally or less potent than parent compounds. However, examples where metabolites inhibited transporters in vitro were identified, supporting the regulatory requirement for in vitro testing of metabolites to enable integrated clinical DDI risk assessment.

SIGNIFICANCE STATEMENT A diverse dataset showed that transporter inhibition often correlated with lipophilicity and molecular weight (>500 Da). Overlapping transporter inhibition was identified, particularly that inhibition of BCRP, OATP1B1, and MATE1 was frequent if the compound inhibited other transporters. In contrast, inhibition of OAT1 did not correlate with the other drug transporters tested.

Footnotes

Received October 25, 2023.
Accepted April 29, 2024.

The work presented in this manuscript did not receive any financial support.
No author has an actual or perceived conflict of interest with the contents of this article.
Initial analysis of this data-set was presented as podium presentations at the 24th North American ISSX meeting, Virtual event (Sep 2021); the 37th JSSX annual meeting, Yokohama, Japan (Nov 2022); and in an IQ webinar in Dec 2023.
dx.doi.org/10.1124/dmd.123.001587.
↵This article has supplemental material available at dmd.aspetjournals.org.