Tyrphostin AG 1295 is a selective inhibitor of PDGFR (platelet-derived growth factor receptor) protein tyrosine kinase (PDGF-receptor PTK)(IC50 = 500 nM) and PDGF-dependent DNA synthesis (IC50 = 2.5 μM) in Swiss/3T3 cells, and demonstrates about 50% inhibition on neointimal formation after balloon injury in porcine femoral arteries. Tyrphostin AG 1295 has been shown to selectively attenuate smooth muscle cell growth in vitro, and to reduce the autophosphorylation of PDGF receptor (R), thereby supressing the enhancement by PDGF-BB without affecting the FGF-2 effect.