Validation of a Kinetic Model of Erlotinib

Inclusion Criteria: * All patients receiving treatment with erlotinib monotherapy for locally advanced or metastatic NSCLC either first line in patients with an activating mutation of the receptor EGF-R or patients with stable disease after 4 cycles of standard first-line chemotherapy with platinum or after failure of at least one prior chemotherapy regimen * Age\> 18 years * Subject has signed an informed consent * Treatment initiated for at least 7 days or dosage changed for at least 7 days Exclusion Criteria: * Contraindication to the use of drug * Subject to exclusion period (as determined by a previous study or in progress) * Inability to give informed information (subject in emergency situations, difficulties in understanding the subject, ...) * Subject under judicial protection * Subject under tutorship or curatorship * Pregnancy (and woman of childbearing age without contraception) * Breastfeeding