Iressa Re-challenge in Advanced NSCLC EGFR-mutated Patients

Inclusion Criteria: * Histologically or cytologically confirmed NSCLC with an activating sensitising EGFR TK mutation as determined before starting the first EGFR-TKI treatment by using a well-validated and robust methodology * Female or male patients aged 18 years or over with locally advanced or metastatic stage IIIB/IV disease, not suitable for therapy of curative intent or stage IV (metastatic) disease, eligible for gefitinib re-challenge treatment for NSCLC who have already received an EGFR-TKI with a documented complete (CR) or partial response (PR) or stable disease (SD) \>12 weeks as the best response to their 1st EGFR-TKI treatment and who have received any subsequent anti-cancer therapy (excluding EGFR-TKIs) treatment, including but not limited to doublet platinum based chemotherapy or docetaxel monotherapy or pemetrexed monotherapy, on which they progressed. * Measurable disease defined as at least one lesion, not previously irradiated, that can be accurately measured at baseline as ≥ 10 mm in the longest diameter (except lymph nodes which must have short axis ≥ 15 mm) with spiral CT or MRI and which is suitable for accurate repeated measurements. * WHO / ECOG / Zubrod performance status 0-2. * Possibility of obtaining tumour material before the start of the study treatment. Exclusion Criteria: * Known severe hypersensitivity to gefitinib or any of the excipients of the product treatment with no persistent radiation toxicity. Previous adjuvant chemotherapy is allowed. * Progressive disease or stable disease (SD) \<12 weeks as best response to the 1st line treatment with an EGFR-TKI * Consideration to require radiotherapy to the lung at the time of study entry or in the near future * Past medical history of interstitial lung disease, drug-induced interstitial disease, radiation pneumonitis which required steroid treatment or any evidence of clinically active interstitial lung disease. Pre-existing idiopathic pulmonary fibrosis evidenced by CT scan at baseline * Known or suspected brain metastases or spinal cord compression, unless treated with surgery and/or radiation. * Any unresolved chronic toxicity greater than CTC grade 2 from previous anticancer therapy * Concomitant use of known CYP 3A4 inducers such as phenytoin, carbamazepine, rifampicin, barbiturates, or St John's Wort * Pregnancy or breast-feeding * As judged by the investigator, any evidence of severe or uncontrolled systemic disease (eg, unstable or uncompensated respiratory, cardiac, hepatic, or renal disease) * Evidence of any other significant clinical disorder or laboratory finding that makes it undesirable for the patient to participate in the study * Other co-existing malignancies or malignancies diagnosed within the last 2 years with the exception of basal cell carcinoma or cervical cancer in situ * Life expectancy of less than 12 weeks * Treatment with a non-approved or investigational drug within 30 days before day 1 of study treatment * Involvement in the planning and/or conduct of the study (applies to both NVALT staff or staff at the study site) * Previous enrolment or treatment in the present study.