New targets for therapy in breast cancer: Small molecule tyrosine kinase inhibitors

Breast Cancer Research

Table 1 Small molecule inhibitors of ErbB tyrosine kinases in clinical development

Agent	EGFR IC₅₀ (μmol/l)	HER2 IC₅₀ (μmol/l)	HER4 IC₅₀ (μmol/l)	Reversible/irreversible	Source
Gefitinib (Iressa™, ZD1839)	0.02	3.7	NR	Reversible	AstraZeneca
Erlotinib (Tarceva™, OSI-774)	0.02	3.5	NR	Reversible	Genentech/Roche
EKB-569	0.038	1.2	NR	Irreversible	Wyeth-Ayerst
TAK-165	NR	0.006	NR	NR	Takeda
GW572016	0.011	0.009	NR	Reversible	GlaxoSmithKline
PKI-166	0.02	0.1	NR	Reversible	Novartis
AEE-788	0.002	0.006	0.16	Reversible	Novartis
CI-1033	0.0008	0.019	0.007	Irreversible	Pfizer

AEE-788 also inhibits KDR with a 50% inhibitory concentration (IC50) of 0.077 μmol/l. NR, not reported. EGFR, epidermal growth factor receptor; HER, human epidermal growth factor receptor.

ISSN: 1465-542X