A Study of Repotrectinib in Pediatric and Young Adult Subjects Harboring ALK, ROS1, OR NTRK1-3 Alterations

Enrollment of subjects into Phase 1 will proceed concurrently by age as follows: * Subjects \<12 years old will initially be enrolled in the Phase 1 part to determine the pediatric RP2D for this age group; once the pediatric RP2D is determined, subjects age \<12 years old may be enrolled into the Phase 2 part of the study. * Subjects 12 to 25 years old will be directly enrolled into the Phase 2 part concurrent with Phase 1 enrollment. Phase 1: Approximately 12 pediatric subjects with locally advanced or metastatic solid tumors, including a primary central nervous system (CNS) tumor, or anaplastic large cell lymphoma (ALCL), with disease progression or who are non-responsive or intolerant to available therapies and for which no standard or available curative therapy exists. Phase 2: Subjects will be enrolled in one of 3 cohorts as follows: Cohort 1: approximately 10-20 subjects with solid tumors characterized by NTRK fusion, TRK tyrosine kinase inhibitor (TKI)-naïve, and centrally confirmed measurable disease at baseline. Cohort 2: approximately 23 subjects with solid tumors characterized by NTRK fusion, TRK TKI-pretreated, and centrally confirmed measurable disease at baseline. Cohort 3: approximately 20 subjects with solid tumors or ALCL characterized by other ALK/ROS1/NTRK alterations or NTRK fusions without centrally confirmed measurable disease not otherwise eligible for Cohort 1 or 2. As of the current protocol amendment, only patients with ROS1 alterations will be enrolled to this cohort.