Reuter, Nicholas F.

7547 Background: Sorafenib is a multikinase inhibitor with single-agent activity in previously treated NSCLC. In an effort to evaluate its single agent activity in previously untreated NSCLC, the NCCTG undertook a front-line “window of opportunity” study. Materials and Methods: Patients with stage IIIB (pleural effusion) or stage IV NSCLC received sorafenib dosed at 400 mg BID continuously, with a cycle defined as 4 weeks. Patients were evaluated weekly during the first 2 cycles with those who progressed rapidly going on to receive standard chemotherapy. Based on a two-stage Fleming design, if only at most 1 confirmed response was observed in the first 20 patients enrolled to stage I, the regimen would be considered ineffective. If 2 or more responses were observed, the study would proceed to stage 2 and accrue an additional 22 patients. If 5 or more confirmed responses were observed, the regimen would be recommended for further testing. Results: The study did not meet the stage I efficacy criteria (only 1 confirmed partial response in the first 20 patients) and was permanently closed after enrolling 25 evaluable patients [15 females, 10 males; 4 stage IIIB, 21 stage IV; median age 67 (45–85)]. 2 patients are still receiving treatment (14 and 15 months). No grade 3 or higher hematologic adverse events were observed. Thirteen (52%) patients had a grade 3 non-hematologic adverse event with fatigue (20%), diarrhea (8%), and dyspnea (8%) being the most common. There was one grade 4 pulmonary hemorrhage. A total of 3 (12%) PRs; and 7 (28%) SD were observed in the 25 patients 7 (28%) patients were progression- free at 24 weeks. Median survival and median time to progression were 8.8 and 2.9 months respectively. Conclusion: While the pre- specified efficacy endpoints were not met, the objective response rate of 12% and median survival of 8.8 months suggest that single agent sorafenib has activity similar to two-drug combinations. The feasibility and utility of the “window of opportunity” design in estimating the activity of novel compounds was demonstrated. Finally, the single-agent activity of sorafenib argues for combination studies with standard chemotherapy agents. No significant financial relationships to disclose.