The purpose of this study is to provide gefitinib treatment to patients who, on completion or closure of other gefitinib clinical studies, were either receiving placebo treatment, or are continuing on the same dose and regimen of gefitinib established in their preceding study, for as long as the patients continue to derive benefit.

Inclusion Criteria:

• Patients who have completed preceding gefitinib therapy from either the 1839IL/0709 (250mg dosing) study or 1839IL/0710 (250mg dosing) study and in the opinion of the investigator may benefit from further gefitinib treatment.
• No more than 14 days lapse in gefitinib treatment between the patient completing the preceding gefitinib clinical study and beginning of this study except when agreed by the AstraZeneca physician.

Exclusion Criteria:

• Any evidence of clinically active interstitial lung disease (patients with chronic,stable, radiographic changes who are asymptomatic need not be excluded).
• In the opinion of the investigator, any evidence of severe or uncontrolled systemic disease (e.g. unstable or uncompensated respiratory, cardiac, hepatic or renal disease).
• Withdrawal, at any time, from the preceding gefitinib study.
• Concomitant use of phenytoin, carbamazepine, rifampicin, barbiturates, or St John's Wort