Identifying the Reactive Metabolites of Tyrosine Kinase Inhibitor Pexidartinib In Vitro Using LC–MS-Based Metabolomic Approaches

• Published in: Chemical research in toxicology Vol. 36; no. 8; pp. 1427 - 1438
• Main Authors: Qin, Xuan, Wang, Yong, MacKenzie, Kevin R., Hakenjos, John M., Chen, Si, Khalil, Saleh M., Jung, Sung Yun, Young, Damian W., Guo, Lei, Li, Feng
• Format: Journal Article
• Language: English
• Published: United States American Chemical Society 21.08.2023
• Subjects: Animals; Chemical and Drug Induced Liver Injury - metabolism; Chromatography, Liquid; Cytochrome P-450 CYP3A - metabolism; Cytochrome P-450 CYP3A Inhibitors - pharmacology; Glutathione - metabolism; Humans; Metabolomics; Mice; Microsomes, Liver - metabolism; Protein Kinase Inhibitors - metabolism; Protein Kinase Inhibitors - pharmacology; Tandem Mass Spectrometry; Tyrosine Kinase Inhibitors
• ISSN: 0893-228X; 1520-5010; 1520-5010
• DOI: 10.1021/acs.chemrestox.3c00164

Pexidartinib (PEX, TURALIO), a selective and potent inhibitor of the macrophage colony-stimulating factor-1 receptor, has been approved for the treatment of tenosynovial giant cell tumor. However, frequent and severe adverse effects have been reported in the clinic, resulting in a boxed warning on PEX for its risk of liver injury. The mechanisms underlying PEX-related hepatotoxicity, particularly metabolism-related toxicity, remain unknown. In the current study, the metabolic activation of PEX was investigated in human/mouse liver microsomes (HLM/MLM) and primary human hepatocytes (PHH) using glutathione (GSH) and methoxyamine (NH2OMe) as trapping reagents. A total of 11 PEX-GSH and 7 PEX-NH2OMe adducts were identified in HLM/MLM using an LC–MS-based metabolomics approach. Additionally, 4 PEX-GSH adducts were detected in the PHH. CYP3A4 and CYP3A5 were identified as the primary enzymes responsible for the formation of these adducts using recombinant human P450s and CYP3A chemical inhibitor ketoconazole. Overall, our studies suggested that PEX metabolism can produce reactive metabolites mediated by CYP3A, and the association of the reactive metabolites with PEX hepatotoxicity needs to be further studied.