Safety but Limited Efficacy of Ensartinib in ROS1-Positive NSCLC: A Single-Arm, Multicenter Phase 2 Study.

Abstract Introduction Some ALK inhibitors with good inhibition of ROS1 in preclinical studies have been reported to be possibly beneficial in ROS1-positive NSCLC. In this work, we studied the efficacy and safety of ensartinib in the treatment of patients with ROS1-positive NSCLC. Methods The exploratory study was a phase 2, single-arm, multicenter design (NCT03608007). Patients with ROS1-positive NSCLC with a previous chemotherapy line number of less than or equal to 1 who received ensartinib at the dose of 225 mg once daily were enrolled. The primary end point was objective response rate evaluated by an investigator per Response Evaluation Criteria in Solid Tumors version 1.1. Results From June 2018 to July 2019, a total of 59 patients were enrolled at 23 centers in the People’s Republic of China. At the time of data cutoff, the median follow-up was 19.8 months (range: 0.8–22.5). The median objective response rate was 27.0 % (95 % confidence interval [CI]: 13.8–44.1) with 10 partial responses. Median duration of response was 4.8 months (95 % CI: 1.8–10.8). The median progression-free survival was 4.6 months (95 % CI: 4.0–6.4). The median overall survival was not estimable (95 % CI: 14.9–not estimable). Of four patients with brain metastases, intracranial disease control was reported in three (75.0 %, 95 % CI: 19.4–99.4). The most common treatment-related adverse events (TRAEs) were rash and liver enzyme abnormalities, with good prognosis after adjustment for dosage and concomitant medication. Most of the TRAEs were of grades 1 to 2, and incidence of grade greater than or equal to 3 TRAEs was 25.4 %. Conclusions Ensartinib had a modest efficacy in patients with ROS1-positive NSCLC with an acceptable safety profile.