CONNECT 1903 is a Phase I/II study evaluating the safety pharmacokinetics/pharmacodynamics, feasibility, and preliminary efficacy of Larotrectinib in pediatric and young adult patients with newly diagnosed high-grade glioma harboring NTRK gene fusions.Larotrectinib is administered at a defined dose, with treatment given alone and/or alongside standard-of-care therapy (including radiotherapy and/or chemotherapy, depending on the study phase and cohort). The primary objective is to assess disease control after initial treatment, along with safety and feasibility. Secondary endpoints include pharmacokinetics/pharmacodynamics, objective response rate (ORR), progression-free survival (PFS), and overall survival (OS). This study targets a molecularly defined subgroup of high-grade glioma, aiming to determine whether TRK inhibition improves clinical outcomes in patients with NTRK fusion–positive tumors.