Evaluation of erlotinib treatment after gefitinib failure in Japanese recurrent non-small cell lung cancer patients

e19008 Background: Both gefitinib (G) and erlotinib (E) belong to the family of epidermal growth factor receptor-tyrosine kinase inhibitors that has shown positive results in the treatment of advanced/recurrent non-small-cell lung cancer (NSCLC). Recent studies suggested a distinction in efficacy between G and E. In fact, there is a subgroup of patients who had clinically meaningful benefit with E therapy after G failure, but little is known about the factors that predict disease control or the risk factors that develop toxicity in these patients. Our aim is to evaluate the efficacy and toxicity of E after G failure in the largest scale study to date. Methods: We retrospectively evaluated the efficacy and toxicity of E therapy and analyzed factors that contributed to disease control in patients had experienced G failure. EGFR mutational analysis was performed in evaluable cases. Results: From January 2008 to December 2008, seventy-seven patients were treated with E after G failure in our institutions. Of these 77 patients, 11 had a partial response (PR) and 21 had a stable disease (SD), resulting in a best response rate of 14% and a disease control rate (DCR) of 42%. Thirty of 56 (54%) patients who had benefited from prior G therapy achieved disease control, while only 2 of 20 (10%) patients who had experienced initial progressive disease to G therapy obtained SD (P<0.001) . Twenty-seven of 48 (56%) patients with performance status (PS) 0/1 achieved disease control, but a DCR of PS 2/3/4 patients was only 17% (5 of 29) (P<0.001). EGFR mutation status, smoking history, and gender had little relationship to disease control. In 4 of 11 patients who achieved PR, E was effective for brain metastases. The most common side effects of E therapy were skin rash and diarrhea, as described in previous studies. Notably in approximately 30% of poor PS patients, grade 3 to 4 non-hematological toxicity including severe general malaise and anorexia was observed. Conclusions: E may be effective as a salvage therapy for some Japanese NSCLC patients after G failure, especially in those who had benefited from prior G treatment and/or those who maintain a good PS. Interestingly, E was effective for brain metastases of some patients after G failure. No significant financial relationships to disclose.