Pharmacodynamic Studies of the Epidermal Growth Factor Receptor Inhibitor ZD1839 in Skin From Cancer Patients: Histopathologic and Molecular Consequences of Receptor Inhibition

Abstract

ZD1839 inhibits EGFR activation and affects downstream receptor-dependent processes in vivo. These effects were profound at doses well below the one producing unacceptable toxicity, a finding that strongly supports pharmacodynamic assessments to select optimal doses instead of a maximum-tolerated dose for definitive efficacy and safety trials.