Phase II Study of Crizotinib in East Asian Patients With ROS1-Positive Advanced Non–Small-Cell Lung Cancer

Purpose Approximately 1% to 2% of non-small-cell lung cancers (NSCLCs) harbor a c-ros oncogene 1 ( ROS1) rearrangement. Crizotinib, an inhibitor of anaplastic lymphoma kinase (ALK), ROS1, and MET, has shown marked antitumor activity in a small expansion cohort of patients with ROS1-positive advanced NSCLC from an ongoing phase I study. We assessed the efficacy and safety of crizotinib in the largest cohort of patients with ROS1-positive advanced NSCLC. Patients and Methods This phase II, open-label, single-arm trial enrolled East Asian patients with ROS1-positive (assessed through validated AmoyDx assay Amoy Diagnostics, Xiamen, China at three regional laboratories) advanced NSCLC who had received three or fewer lines of prior systemic therapies. Patients were to receive oral crizotinib at a starting dose of 250 mg twice daily and continued treatment until Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1-defined progression (by independent radiology review IRR), unacceptable toxicity, or withdrawal of consent. The primary end point was objective response rate (ORR) by IRR. Results In the efficacy and safety analyses, 127 patients were included, with 49.6% still receiving treatment at data cutoff. ORR by IRR was 71.7% (95% CI, 63.0% to 79.3%), with 17 complete responses and 74 partial responses. ORRs were similar irrespective of the number of prior lines of therapy, and responses were durable (median duration of response, 19.7 months; 95% CI, 14.1 months to not reached). Median progression-free survival by IRR was 15.9 months (95% CI, 12.9 to 24.0 months). No new safety signals associated with crizotinib were reported. Conclusion This study demonstrated clinically meaningful benefit and durable responses with crizotinib in East Asian patients with ROS1-positive advanced NSCLC. Crizotinib was generally well tolerated, with a safety profile consistent with previous reports.