The purpose of this study is to assess the safety and effectiveness of the investigational drug imetelstat in children with malignant glioma, diffuse intrinsic pontine glioma, medulloblastoma/primitive neuroectodermal tumor, or ependymoma that has continued to grow or has come back despite standard therapy. This study is being conducted as part of the Pediatric Brain Tumor Consortium, a group of U.S. centers dedicated to advancing the treatment of brain tumors in children.
Imetelstat works by inhibiting the activity of an enzyme called telomerase. This enzyme helps extend the ends of chromosomes (telomeres). Cancer cells must maintain the lengths of their telomeres to continue to grow, and they use telomerase to accomplish this. Telomerase is active in most pediatric solid tumors.
Imetelstat is given intravenously (by vein).