I. To determine the objective response rate (ORR; complete response + partial response) in pediatric patients treated with Trk inhibitor LOXO-101 (LOXO-101) (larotrectinib) with advanced solid tumors (including central nervous system [CNS] tumors), non-Hodgkin lymphomas or histiocytic disorders harboring NTRK 1/2/3 fusions.