Entrectinib (RXDX-101) is a medication being studied for its potential to treat pediatric patients with locally advanced or metastatic solid tumors, or primary central nervous system (CNS) tumors. It is particularly focused on patients who have no satisfactory treatment options available. The trial aims to determine the most effective and safe dose of entrectinib for children, whether they can swallow capsules or need the medication administered through a feeding tube. The study also evaluates how well the medication works in shrinking tumors that have specific genetic changes, known as NTRK1/2/3 or ROS1 gene fusions. The effectiveness of the treatment is assessed using specific criteria for measuring tumor response.

Pediatric Solid Tumors – These are abnormal masses of tissue that can occur in various parts of a child’s body, such as bones, muscles, or organs. They develop when cells grow uncontrollably and form a lump or mass. The progression of these tumors can vary widely depending on their location and type. Some may grow slowly and remain localized, while others can grow rapidly and spread to other parts of the body. Symptoms often depend on the tumor’s size and location, potentially causing pain, swelling, or functional impairment. Early detection and monitoring are crucial for managing these tumors effectively.

Primary Central Nervous System (CNS) Tumors – These tumors originate in the brain or spinal cord and can affect children. They arise from various types of cells within the central nervous system and can be either benign or malignant. The progression of CNS tumors can lead to increased pressure within the skull, causing headaches, nausea, or changes in behavior. Depending on their location, they may also affect movement, balance, or cognitive functions. The growth rate and impact of these tumors can vary, necessitating careful observation and management.