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Gaining Mechanistic Insight Into Coproporphyrin I as Endogenous Biomarker for OATP1B‐Mediated Drug–Drug Interactions Using Population Pharmacokinetic Modeling and Simulation

Lookup NU author(s): Dr Shelby BarnettORCiD



This work is licensed under a Creative Commons Attribution 4.0 International License (CC BY 4.0).


This study evaluated coproporphyrin I (CPI) as a selective endogenous biomarker of OATP1B‐mediated drug–drug interactions (DDIs) relative to clinical probe rosuvastatin using nonlinear mixed‐effect modeling. Plasma and urine CPI data in the presence/absence of rifampicin were modeled to describe CPI synthesis, elimination clearances, and obtain rifampicin in vivo OATP Ki. The biomarker showed stable interoccasion baseline concentrations and low interindividual variability (<25%) in subjects with wildtype SLCO1B1. Biliary excretion was the dominant CPI elimination route (maximal >85%). Estimated rifampicin in vivo unbound OATP Ki (0.13 μM) using CPI data was 2‐fold lower relative to rosuvastatin. Model‐based simulations and power calculations confirmed sensitivity of CPI to identify moderate and weak OATP1B inhibitors in an adequately powered clinical study. Current analysis provides the most detailed evaluation of CPI as an endogenous OATP1B biomarker to support optimal DDI study design; further pharmacogenomic and DDI data with a panel of inhibitors are required.

Publication metadata

Author(s): Barnett S, Ogungbenro K, Ménochet K, Shen H, Lai Y, Humphreys WG, Galetin A

Publication type: Article

Publication status: Published

Journal: Clinical Pharmacology & Therapeutics

Year: 2018

Volume: 104

Issue: 3

Pages: 564-574

Print publication date: 27/08/2018

Online publication date: 15/12/2017

Acceptance date: 05/12/2017

Date deposited: 11/03/2021

ISSN (print): 0009-9236

ISSN (electronic): 1532-6535

Publisher: John Wiley & Sons, Inc.


DOI: 10.1002/cpt.983

PubMed id: 29243231


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