Background:

Gefitinib, also known as ZD1839 or Iressa, is a potent and orally-bioavailable small-molecule inhibitor of epidermal growth factor receptor (EGFR) tyrosine kinase with 50% inhibition concentration IC₅₀values of 0.033 μM and 0.027 μM in A431 membrane prep and baculovirus lysate respectively. Gefitinib binds to the kinase ATP binding site of EGFR interfering with the binding of adenosine triphosphate, which suppresses the EGFR tyrosine kinase activity and resultant signal transduction of EGFR. Gefitinib exhibits anti-angiogenic activities in a wide range of human tumor types, including head and neck, prostate, breast, ovarian, colon, small-cell lung and non-small-cell lung cancer. Moreover, geftinib has also been found to reduce proliferation, induce cell cycle arrest and increase apoptosis.

Reference

[1].M. Ranson and S. Wardell. Gefitinib, a novel, orally administered agent for the treatment of cancer. Journal of Clinical Pharmacy and Therapeutics (2004) 29, 95-103
[2].Joachim Von Pawel. Gefitinib (Iressa, ZD1839): a novel targeted approach for the treatment of solid tumors. Bull Cancer 2004; 91(5): E70-E76