Erlotinib as 1st Line Treatment in NSCLC Stage IIIB/IV

Inclusion Criteria: * Histologically or cytologically confirmed, unresectable locally advanced (stage IIIB with pleural effusion) and/or metastatic (stage IV) NSCLC * No previous therapy for advanced/metastatic NSCLC is allowed * age \>18 years * bidimensionally measurable disease * non-smokers (or ex-smokers with less than 5 pack-years smoking history) * adenocarcinoma histology * performance status (WHO) 0-3 * adequate liver (serum bilirubin \<1.5 times the upper normal limit (UNL); AST and ALT \<2.5 times the UNL in the absence of demonstrable liver metastases, or \<5 times the UNL in the presence of liver metastases); adequate renal function (serum creatinine \<1.5 times the UNL); and bone marrow (neutrophils ≥ 1.5x 109 /L, and platelets ≥ 100x 109 /L) function * previous radiotherapy, either in the adjuvant setting or for the treatment of metastatic disease is allowed provided that the measurable lesions are outside the radiation fields * patient able to take oral medication * tissue sample for tumour mutational analysis is required Exclusion Criteria: * serious chronic skin conditions (e.g. psoriasis, eczema) that would preclude study participation * active infection * history of significant cardiac disease (unstable angina, congestive heart failure, myocardial infarction within the previous 6 months, ventricular arrhythmias) * malnutrition (loss of ≥ 20% of the original body weight) * performance status: 4 * psychiatric illness or social situation that would preclude study compliance * pregnant or lactating women