Preclinical analysis of the analinoquinazoline AG1478, a specific small molecule inhibitor of EGF receptor tyrosine kinase

• Published in: Biochemical pharmacology Vol. 71; no. 10; pp. 1422 - 1434
• Main Authors: Ellis, A.G., Doherty, M.M., Walker, F., Weinstock, J., Nerrie, M., Vitali, A., Murphy, R., Johns, T.G., Scott, A.M., Levitzki, A., McLachlan, G., Webster, L.K., Burgess, A.W., Nice, E.C.
• Format: Journal Article
• Language: English
• Published: New York, NY Elsevier Inc 14.05.2006; Elsevier Science
• Subjects: AG1478; Animals; Area Under Curve; Biological and medical sciences; Cell Line, Tumor; Dose-Response Relationship, Drug; EGFR receptor; Enzyme Inhibitors - chemistry; Enzyme Inhibitors - pharmacokinetics; Enzyme Inhibitors - pharmacology; Glioblastoma - drug therapy; Glioblastoma - metabolism; Glioblastoma - pathology; Humans; Injections, Intravenous; Injections, Subcutaneous; Medical sciences; Mice; Microphysiometer; Molecular Structure; Pharmacokinetics; Pharmacology. Drug treatments; Protein Tyrosine Phosphatases - antagonists & inhibitors; Quinazoline; Quinazolines; Rats; Receptor, Epidermal Growth Factor - antagonists & inhibitors; Thymidine - metabolism; Tyrosine kinase inhibitor; Tyrphostins - chemistry; Tyrphostins - pharmacokinetics; Tyrphostins - pharmacology; Xenograft Model Antitumor Assays; AG1478; Microphysiometer; Quinazoline; Pharmacokinetics; Tyrosine kinase inhibitor; EGFR receptor; Enzyme; Transferases; Preclinical trial; Enzyme inhibitor; Receptor tyrosine kinase; trk receptor; Epidermal growth factor receptor; Small molecule; Protein-tyrosine kinase
• ISSN: 0006-2952; 1873-2968
• DOI: 10.1016/j.bcp.2006.01.020

The tyrphostin 4-(3-chloroanilino)-6,7-dimethoxyquinazoline (AG1478) is a potent and specific inhibitor of EGFR tyrosine kinase whose favourable preclinical profile supports progression towards clinical trials. Microphysiometric evaluation revealed a short (<24 min) effective inhibition of cellular receptor response to EGF challenge in BaF/ERX cells indicating a need to maintain sustained levels of inhibitor. Initial pharmacokinetic evaluation in mice of novel AG1478 formulations in a beta-cyclodextrin (Captisol ®) showed monoexponential elimination from plasma (half-life 30 min) following subcutaneous administration. A two-fold dose escalation gave a 2.4-fold increase in the total AUC. Bolus i.v. and 6 h continuous infusion were investigated in rats to mimic a more clinically relevant administration regimen. Drug elimination following bolus i.v. administration was biphasic (terminal elimination half-life 30–48 min). The linear relationship between dose and AUC 0→∞ ( r 2 = 0.979) enabled the prediction of infusion rates and doses for sustained delivery using continuous 6 h infusions, where steady state was reached in 120 min. Plasma levels of AG1478 >10 μM were achieved over the duration of the infusion. At the lowest dose, plasma drug levels after the cessation of infusion declined with a half-life of approximately 43 min. EGFR activity, measured both by autophosphorylation and downstream signalling, was inhibited in a dose-dependent manner by injection of AG1478 in mice bearing xenografts of the human glioblastoma cell line U87MG.Δ2-7, which expresses a constitutively active variant of the EGF receptor. Taken together, these experiments provide essential data to assess the anti-tumour efficacy of AG1478 and will assist in the rational design of dose regimens for clinical studies.