Interaction between crizotinib and tropifexor through <i>in vitro</i> and <i>in vivo</i> studies

In the context of cancer treatment, the employment of multiple drug therapies frequently results in a high prevalence of drug-drug interaction (DDI) in clinical practice. Crizotinib is a tyrosine kinase inhibitor (TKI) used to treat non-small cell lung cancer (NSCLC). Tropifexor is a Farnesoid X Receptor (FXR) agonist used to treat non-alcoholic steatohepatitis (NASH) and other metabolic disorders. This study developed an ultra performance liquid chromatography-tandem mass spectrometry (UPLC-MS/MS) method for the quantitative determination of crizotinib and 2-Keto crizotinib concentrations and investigated the effect of tropifexor on crizotinib metabolism. Results showed good linearity for crizotinib and 2-Keto crizotinib in plasma, with the method meeting all quantitative analysis requirements, including selectivity, accuracy, precision, stability, matrix effects, and recovery. In rat liver microsomes (RLM), tropifexor inhibited the metabolism of crizotinib <i>via</i> non-competitive and uncompetitive mechanisms, whereas in human liver microsomes (HLM), the inhibition occured through competitive and non-competitive mechanisms. <i>In vivo</i> studies in rats demonstrated that tropifexor significantly increased the AUC_0-t, AUC_0-∞, and C_max of crizotinib by 35.7%, 36.9%, and 37.5%, respectively, and decreased the CL_z/F of crizotinib by 25.2%. For the metabolite 2-Keto crizotinib, tropifexor reduced its CL_z/F by 27.9%. Our study developed this UPLC-MS/MS method for the accurate and sensitive quantitative determination of crizotinib and 2-Keto crizotinib concentrations, and elucidated the inhibitory effect of tropifexor on crizotinib metabolism and its inhibitory mechanism. The results of this study will support the necessity of monitoring crizotinib plasma concentrations when used in combination therapy.