Biomarker-Based Prediction of OATP1B1 Activity in Clinical Routine — Investigating Coproporphyrins as Markers for Drug-Drug-Gene Interactions.

Coproporphyrin I (CPI) as an in vivo OATP1B1 activity proxy to detect drug-drug-gene interactions in clinical routine

Coproporphyrin I (CPI) is a validated endogenous biomarker for OATP1B1 (SLCO1B1) activity. This study evaluates whether CPI concentrations measured in clinical routine from polymedicated patients (pharmacist-led medication reviews) can predict OATP1B1 activity by integrating genotype and co-medication. CPI levels were associated with SLCO1B1 genotype-predicted phenotype and putative OATP1B1 inhibitor intake. Patients with decreased/normal function phenotypes taking inhibitors showed CPI levels comparable to patients with poor/decreased function phenotype without inhibitors, consistent with phenoconversion.

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This study provides a first proof of concept that CPI can detect OATP1B1 drug-drug-gene interactions in real-world clinical routine settings, where genotyping alone is insufficient (medication-induced phenoconversion). If confirmed at larger scale, this biomarker could be integrated into medication reviews to identify patients at risk of SLCO1B1 interactions without requiring systematic genotyping.

Clinical impact : 2/3 · Evidence quality : 2/3 · Novelty : 2/2 · Sample size : 0/1 · Journal quality : 1/1 → Total : 7/10