Weekly Dosing With the Platelet-Derived Growth Factor Receptor Tyrosine Kinase Inhibitor SU9518 Significantly Inhibits Arterial Stenosis

Abstract

Abstract —The platelet-derived growth factor (PDGF) ligands and their receptors have been implicated as critical regulators of the formation of arterial lesions after tissue injury. SU9518 (3[5-{5-bromo-2-oxo-1,2-dihydroindol-3-ylidenemethyl}-2,4-dimethyl-1 H -pyrrol-3-yl]propionic acid) is a novel synthetic indolinone that potently and selectively inhibits the cellular PDGF receptor kinase and PDGF receptor–induced cell proliferation. Inhibition of PDGF receptor phosphorylation in cell-based assays occurs within 5 minutes after drug exposure and persists for >6 hours after drug removal. The pharmacokinetics indicate plasma levels that exceeded the effective concentration required to inhibit the PDGF receptor in cells for up to 8 hours or 7 days after a single oral or subcutaneous administration, respectively. In the rat balloon arterial injury–induced stenosis model, once-daily oral or once-weekly subcutaneous administration of SU9518 reduced intimal thickening of the carotid artery (ratio of neointimal to medial area, 1.94±0.38 versus 1.03±0.29 [ P <0.01] 2.21±0.32 versus 1.34±0.45 [ P <0.01], respectively). These studies provide the rationale to evaluate PDGF receptor tyrosine kinase inhibitors, including inhibitors related to the indolinone, SU9518, for the treatment of arterial restenosis.