OA02.03 Clinical Activity of Lorlatinib in Patients with ROS1+ Advanced Non-Small Cell Lung Cancer: Phase 2 Study Cohort EXP-6

Among patients with ROS1-positive non-small cell lung cancer (NSCLC), most achieve initial benefit from crizotinib treatment but often develop resistance, and further treatment options are limited. Lorlatinib is a potent, brain-penetrant third-generation ALK/ROS1 TKI with broad mutational coverage. It has shown compelling clinical activity in patients with ALK-positive and ROS1-positive advanced NSCLC, most of whom had CNS metastases and had received prior crizotinib. This ongoing Phase 2 study (NCT01970865) enrolled patients with ROS1-positive advanced NSCLC ± asymptomatic CNS metastases without restriction on the type or number of prior lines of therapy (cohort EXP-6). Patients received lorlatinib 100 mg QD. Primary endpoints were overall and intracranial response by independent central review. Secondary endpoints included duration of response and progression-free survival. Safety was assessed in all treated patients (cohorts EXP-1–6); molecular profiling is ongoing. As of the data cut-off (02 Feb 2018), 47 patients with ROS1+ NSCLC were treated; 25 had baseline CNS metastases; 34 had received prior crizotinib and 13 were crizotinib-naïve. Treatment with lorlatinib led to rapid and durable responses in both crizotinib-naïve and crizotinib-pre-exposed patients (Table). The most common treatment-related adverse events (TRAEs) in EXP-6, were hypercholesterolemia (83%) and hypertriglyceridemia (60%). In EXP-6, 36% and 23% of patients had TRAEs leading to dose interruptions and dose reductions, respectively. No permanent treatment discontinuations due to TRAEs or treatment-related deaths occurred. Lorlatinib showed clinically meaningful benefit in patients with ROS1-positive NSCLC, including those who had received prior crizotinib or were crizotinib-naive, as demonstrated by rapid and durable responses. These findings further suggest that the activity of lorlatinib differs depending on prior exposure to crizotinib. The safety profile of lorlatinib in ROS1 patients was comparable to that previously reported in the overall ALK/ROS1 population.