Inclusion Criteria:
- Male or female patients ≥18 years old with a life expectancy of at least 8 weeks
- Radiographically proven recurrent (≥ first relapse), intracranial Glioblastoma (GBM)
- For all patients, availability of at least 10 unstained slides (or archival tumor block sufficient to generate at least 10 unstained slides) from any previous GBM surgery
- Previous treatment with external beam radiation and temozolomide chemotherapy
- Before the first dose of PLX3397,adequate recovery from toxicity of prior therapy as follows:
>28 days for cytotoxic therapy >42 days for nitrosoureas >28 days for bevacizumab >7 days for non cytotoxic therapy such as interferon, tamoxifen, thalidomide, cis-retinoic acid, or erlotinib
- Women of child-bearing potential must have a negative pregnancy test within 7 days of initiation of dosing and must agree to use an acceptable method of birth control while on study drug and for 3 months after the last dose. Women of non-childbearing potential may be included if they are either surgically sterile or have been postmenopausal for ≥1 year. Men of child-bearing potential must also agree to use an acceptable method of birth control while on study drug.
- Karnofsky performance status of ≥60
- Adequate hematologic, hepatic, and renal function (absolute neutrophil count ≥1.0 x 109/L, Hgb >9 g/dL, platelet count ≥50 x 109/L, Aspartate aminotransferase/Alanine aminotransferase (AST/ALT) ≤2.5x Upper Limit of Normal (ULN), creatinine ≤1.5x ULN)
- Willing and able to provide written informed consent prior to any study related procedures and to comply with all study requirements
Exclusion Criteria:
- Investigational drug use within 28 days of the first dose of PLX3397
- GBM progression within 3 months of previous radiation by Response Assessment in Neuro-Oncology (RANO) criteria
- History of Grade 2 Common Toxicity Criteria for Adverse Events (CTCAE v4) or greater acute intracranial hemorrhage
- Previous failure of bevacizumab or other vascular endothelial growth factor (VEGF) therapy except in a first line setting
- History of malignant glioma with co-deletion of 1p/19q
- A concurrent active cancer that requires non-surgical therapy (e.g. chemotherapy, radiation, adjuvant therapy). Prior history of other cancer is allowed, as long as there was no active disease within the prior 3 years.
- Refractory nausea and vomiting, malabsorption, biliary shunt, or significant bowel resection that would preclude adequate absorption
- Patients with serious illnesses, uncontrolled infection, medical conditions, or other medical history including abnormal laboratory results, which in the investigator's opinion would be likely to interfere with a patient's participation in the study, or with the interpretation of the results
- Women of child-bearing potential who are pregnant or breast feeding
- corrected QT interval (QTc) ≥450 msec at Screening