IFCT-GFPC 05.02 A Randomized Phase III Trial Assessing in Patients With Advanced Non-small Cell Lung Cancer

The objective of this trial is to improve the duration of control disease for PS 0-1 patients who are not progressing on first-line cisplatin-gemcitabine chemotherapy. Standard therapy is for these patients to stop first-line chemotherapy after 4 to 6 cycles and to begin a second-line chemotherapy when progression of disease is occurring. Two approaches will be experimented in this trial in attempt to prolong progression free survival : * Maintenance chemotherapy with single-agent gemcitabine continued till disease progression or toxicity. * Sequential treatment with erlotinib immediately given after the end of first-line chemotherapy.