- Patients with a diagnosis of a primary CNS malignancy (including low-grade glioma) that is recurrent or refractory to standard therapy and for which there is no known curative therapy; all patients must have had histological verification of malignancy at initial diagnosis or relapse, excluding patients with diffuse intrinsic brain stem tumors, optic pathway tumors or CNS germ cell tumors with elevations of reliable serum or CSF tumor markers (alpha-fetoprotein or beta-HCG); patients with intrinsic pontine gliomas or optic pathway tumors do not require histological confirmation of disease but should have clinical and/or radiographic evidence of progression