OSI-420, Free Base (Desmethyl Erlotinib)

OSI-420 is a metabolite of Erlotinib. Erlontinib potently inhibits EGFR autophosphorylation in cultured human head and neck tumor cells, a cell line which exhibits high levels of EGFR. Erlotinib also inhibits the proliferation of PC-9 cell lines, which contain a deletion mutation on exon 19 of the EGFR gene. A combination of Erlotinib and rapamycin produced a synergistic inhibitory effect on cell growth.