<qa>  What is the only evidence of definitive clinical benefit provided by an EGFR inhibitor in cancer patientsAs previously described, TarcevaTM has recently been shown to prolong survival in a large, randomized, placebo-controlled Phase III trial including 731 NSCLC patients no longer candidates for further chemotherapy. This is the first and so far the only evidence of definitive clinical benefit provided by an EGFR inhibitor in cancer patients. TarcevaTM is the standard of care for second and third line treatment for lung cancer in USA and Europe. However, the experience with this agent in the Middle Eastern population is very limited. The rationale for this program is to evaluate the pattern of TarcevaTM use in patients with advanced inoperable stage III or IV NSCLC who have failed standard treatment, or patients who can not receive other systemic anticancer therapy, or patients who are not medically suitable for chemotherapy e.g., poor performance status. This will also enable us to study the efficacy and safety of TarcevaTM in this population, as there may be differences in the pharmacogenomic of this population and the previously studied population. 