Larotrectinib is a medication being studied for its ability to control disease in young children with newly diagnosed high-grade glioma that has a specific genetic feature called NTRK fusion. The trial aims to see how well the medication works on its own after two treatment cycles. Additionally, the study is looking at how safe and feasible it is to use larotrectinib in combination with chemotherapy, as well as its safety when given after targeted radiation therapy.

High Grade Glioma (HGG) – This is a type of aggressive brain tumor that originates from glial cells, which support and protect nerve cells in the brain. It is characterized by rapid growth and a tendency to infiltrate surrounding brain tissue, making it challenging to manage. Symptoms can vary depending on the tumor’s location but often include headaches, seizures, and neurological deficits. HGG is known for its high cellularity and abnormal blood vessel formation. It can occur in both children and adults, with varying subtypes based on genetic and molecular features.

Diffuse Intrinsic Pontine Glioma (DIPG) – This is a rare and aggressive brain tumor that primarily affects children, occurring in the pons region of the brainstem. It is characterized by its diffuse growth pattern, which means it spreads widely throughout the brain tissue, making surgical removal impossible. Symptoms often include problems with balance and coordination, facial weakness, and difficulty with eye movements. DIPG progresses rapidly, leading to worsening neurological function over time. The tumor’s location in the brainstem affects vital functions, contributing to its complexity.