The purpose of this study is to determine whether continuing erlotinib beyond disease progression in combination with chemotherapy is beneficial for NSCLC patients who have EGFR mutant disease or who have responded to EGFR TKI.

A Phase II randomised, multicenter study to assess the efficacy and safety of continuing erlotinib in addition to chemotherapy versus chemotherapy alone in patients who have EGFR mutant or EGFR TKI responsive NSCLC and have progressed on EGFR TKI.

Inclusion Criteria:

• Histologically confirmed stage IIIB/IV NSCLC.
• Investigator confirmed progression according RECIST 1.1 during EGFR TKI treatment within 28 days of the randomization
• Activating mutation (G719A/C/S; Exon 19 insertion/deletion; L858R; L861Q) in the EGFR gene or have had at least partial response with EGFR TKI lasting ≥ 6 months
• Performance status: WHO 0-2
• Measurable disease according to RECIST 1.1
• Patients must be able to comply with study treatments
• Women with child-bearing potential and men with reproductive potential must be willing to practice acceptable methods of birth control during the study
• Neutrophils ≥ 1'000/μl, Platelets ≥ 100'000/μl, Alanine amino transferase ≤ 2.5 × Upper limit of normal (ULN) (< 5 × ULN if liver metastases), Alkaline phosphatase ≤ 2.5 × ULN (< 5 × ULN if liver metastases), Serum bilirubin ≤ 1.5 × ULN, Serum Creatinine ≤ 1.5 × ULN.
• Patient must be able to comply with the protocol

Exclusion Criteria:

• RECIST 1.1 defined disease progression for more than 28 days while on previous EGFR TKI treatment.
• Patient has been treated with any investigational agent for any indication within 4 weeks of study treatment.
• Patient has history of hypersensitivity or intolerance to erlotinib or gefitinib.
• Patient has history of hypersensitivity or intolerance to chemotherapeutic agents used in the study.
• Patient with symptomatic central nervous system metastases
• Patient has known active hepatitis B or C, or HIV infection
• Pregnant or breastfeeding.
• Patient with uncontrolled undercurrent illness or circumstances that could limit compliance with the study