ZD 1839 "Iressa"

ZD 1839 is a highly specific EGF receptor tyrosine kinase inhibitor. Inhibi tion of EGF receptor transphosphorylation by ZD 1839 blocks the signal tran sduction at the first step, thus providing antiproliferative effects. Precl inical studies demonstrated efficacy and good bioavailability. The terminal of the compound in patients is ranging from 27 to 41 hours; allowing singl e oral dosing Tolerance in healthy volunteers was excellent. In phase I stu dies toxicity was manageable. Most common side effects were skin rash, naus ea, vomiting, and diarrhea. During those studies, clinical responses were o bserved in patients with various malignant tumors in particular non small c ell lung cancer. Phase II and III studies are ongoing.