Evaluation of Biologic End Points and Pharmacokinetics in Patients With Metastatic Breast Cancer After Treatment With Erlotinib, an Epidermal Growth Factor Receptor Tyrosine Kinase Inhibitor

Abstract

Erlotinib has inhibitory biologic effects on normal surrogate tissues and on an EGFR-positive tumor. The lack of reduced tumor proliferation may be attributed to the heterogeneous expression of receptor in the EGFR-positive patient and absence of target in this cohort of heavily pretreated patients.