Tepotinib

Tepotinib is an oral c‑MET tyrosine kinase inhibitor that exerts antitumor effects primarily by blocking the HGF/c‑MET signaling pathway. It has been approved for advanced or metastatic non-small cell lung cancer with MET exon 14 skipping mutations, and is also being clinically investigated in hepatocellular carcinoma and colorectal cancer. In addition to inhibiting c‑MET, Tepotinib can directly bind to and reversibly inhibit the drug-binding sites of ABCB1 and ABCG2 (without downregulating protein expression, altering membrane localization, or showing obvious effects on ABCC1), thereby inhibiting ABC transporter-mediated efflux function and affecting multidrug resistance (MDR) and drug interaction-related ABC‑CYP pathways; it inhibits CYP2C9, CYP3A4 (recombinant enzyme), CYP2C19, and CYP2C8 to varying degrees.

At the cellular level, Tepotinib can significantly reverse multidrug resistance at low micromolar concentrations in MDR cell lines overexpressing ABCB1 or ABCG2 and in patient-derived ex vivo NSCLC tumor samples. The IC₅₀ for inhibiting ABCB1 efflux is approximately in the low micromolar range (Hoechst 33342 and calcein AM accumulation assays), and the EC₅₀ for stimulating ABCG2 ATPase activity is 1.23 µM, with ATPase activity increased by up to approximately 7.6-fold (20 µM). Enzymatically, Tepotinib inhibits CYP2C9 with an IC₅₀ of 1.70 µM, CYP3A4 (recombinant enzyme) with an IC₅₀ of 5.66 µM, and CYP2C19 and CYP2C8 with IC₅₀ values of 16.9 µM and 20.4 µM, respectively, while no obvious reversal of docetaxel resistance was observed in intact HepG2‑CYP3A4 cells. Common experimental concentrations are: approximately 5 µM against ABCB1 and approximately 10 µM against ABCG2 in MDR reversal assays in combination with daunorubicin or mitoxantrone, or 1–3 µM (below IC₂₀, cell viability >80%) to enhance the cytotoxicity of mitoxantrone and topotecan, and 1.5 µM for gene expression/induction studies; 30 µM is commonly used in CETSA binding assays to verify direct binding to ABC transporters.

At the animal level, Tepotinib has mainly been evaluated as a therapeutic agent for its antitumor and resistance-reversing effects in human tumor xenograft models in nude mice. In a subcutaneous xenograft model established with NCI‑H460 and its topotecan-resistant derivative NCI‑H460/TPT10, Tepotinib 30 mg/kg alone showed only moderate tumor inhibition against parental tumors (IRW≈27%, IRV≈14% based on body weight/volume metrics), whereas when combined with topotecan 3 mg/kg, it significantly increased intratumoral topotecan concentration in resistant tumors by approximately 3-fold, raising the tumor inhibition rate to IRW≈83% and IRV≈88%, with no obvious body weight loss or hematological toxicity observed, suggesting that it achieves topotecan resensitization by inhibiting ABCB1/ABCG2 efflux.

References:

[1] Vagiannis D, Budagaga Y, Morell A, Zhang Y, Novotná E, Skarka A, Kammerer S, Küpper JH, Hanke I, Rozkoš T, Hofman J. Tepotinib Inhibits Several Drug Efflux Transporters and Biotransformation Enzymes: The Role in Drug-Drug Interactions and Targeting Cytostatic Resistance In Vitro and Ex Vivo. Int J Mol Sci. 2021 Nov 3;22(21):11936. doi: 10.3390/ijms222111936. PMID: 34769363; PMCID: PMC8584989.

[2] Wu ZX, Teng QX, Yang Y, Acharekar N, Wang JQ, He M, Yoganathan S, Lin J, Wang J, Chen ZS. MET inhibitor tepotinib antagonizes multidrug resistance mediated by ABCG2 transporter: In vitro and in vivo study. Acta Pharm Sin B. 2022 May;12(5):2609-2618. doi: 10.1016/j.apsb.2021.12.018. Epub 2021 Dec 30. PMID: 35646541; PMCID: PMC9136566.