An Open Label Dose Escalation Safety Study of Convection-Enhanced Delivery of IL13-PE38QQR in Patients With Progressive Pediatric Diffuse Infiltrating Brainstem Glioma and Supratentorial High-grade Glioma

Background: * Diffusely infiltrating pontine glioma (DIPG) or supratentorial high-grade glioma (HGG) are brain tumors that are often difficult to treat. It is very difficult to get chemotherapy agents to tumors in the brain, and researchers are looking for new methods to directly treat these types of cancer. * IL-13 is an immune molecule normally occurring in the body. Patients with gliomas appear to have significant amounts of the IL-13 receptors in their brain tumors. An experimental drug, IL13-PE38QQR, combines a bacteria toxin with human IL-13 to allow the toxin to enter and destroy the tumor cell. Early clinical studies suggest this treatment may prolong survival of patients with these types of brain tumors. * A technique called convection-enhanced delivery (CED) uses continuous pressure to push large molecules through the membranes protecting the brain to reach brain tumors. This technique can treat a tumor more directly than with traditional methods. Objectives: * To test the safety and feasibility of giving IL13-PE38QQR directly into regions of the brain in pediatric patients with DIPG or HGG, using CED. * To determine the most appropriate dose of IL13-PE38QQR to treat DIPG or HGG. * To determine the effects of this experimental therapy on the tumor. * To evaluate the physical changes in the tumor before and after the therapy. Eligibility: * Patients who are less than 18 years of age and have been diagnosed with either DIPG or with supratentorial HGG that has not responded well to standard treatments. Design: * Patients will be admitted to the hospital and will receive a magnetic resonance imaging (MRI) scan to show the exact location of the tumor. A small plastic tube will be inserted surgically into the tumor area, and IL13-PE38QQR and a MRI contrast agent (gadolinium DTPA) will be infused into the area. * MRI scans will monitor the process, and the tube will be removed after surgery. * Doses will be adjusted over the course of the study. * Patients