This open-label, multicenter, Phase I, dose-escalating study will evaluate the safety and tolerability, pharmacokinetics, pharmacodynamics and efficacy of GDC-0084 in patients with progressive or recurrent high-grade glioma. Stage 1 is the dose escalation part of the study. Stage 2, patients will receive GDC-0084 at a recommended dose for future studies.

Inclusion Criteria:

• Adult patients, >/= 18 years of age
• Interval of at least 12 weeks from completion of adjuvant radiotherapy for gliomas to study entry
• Karnofsky Performance Status of >/= 70 at screening
• Confirmed measurable disease per RANO
• Adequate hematologic and organ function

Patients enrolled in Stage 1:

• Histologically documented recurrent or progressive high-grade gliomas (WHO Grade III-IV)
• Prior treatment with at least one regimen for gliomas (radiotherapy with or without chemotherapy for Grade III gliomas and radiotherapy with chemotherapy for Grade IV gliomas) and/or not considered to be a candidate for regimens known to provide clinical benefit

Patients enrolled in Stage 2:

• Histologically documented recurrent or progressive glioblastoma (WHO Grade IV gliomas)
• Prior treatment with one or two regimens for glioblastoma (with the initial regimen consisting of radiotherapy with chemotherapy)

Exclusion Criteria:

• Treatment with anti-tumor therapy (approved or experimental) within 4 weeks prior to initiation of study drug
• Requirement for anticoagulants such as warfarin or any other warfarin-derivative anticoagulants; low-molecular-weight heparin is permitted
• Any contraindication to MRI examination
• Evidence of Grade >/= 1 intracranial hemorrhage
• Active congestive heart failure or ventricular arrhythmia requiring medication
• Clinically significant history of liver disease, including viral or other hepatitis, current alcohol abuse or cirrhosis
• Unresolved toxicity from prior therapy with the exception of lymphopenia (for patients with prior temozolomide) and alopecia
• Pregnant or lactating women