Inclusion Criteria:

- Tumor eligibility: Primary Cohort: Measurable disease; Exploratory Cohort:
Measurable disease as defined above or non-measurable/evaluable disease (eg,
progressing non-enhancing lesions).

- Histologically or cytologically confirmed recurrent GBM in 1st or 2nd relapse:
Primary Cohort: Recurrence following radiation therapy and temozolomide, less than or
equal to 2 prior chemotherapeutic regimens; Exploratory cohort: Prior radiation
therapy, temozolomide, and bevacizumab, Recurrence of disease within 2-4 weeks of
last bevacizumab dose.

- Stable dose of corticosteroids for greater than or equal to 5 days prior to baseline
Magnetic Resonance Imaging (MRI)

- Adequate organ function

- Eastern Cooperative Oncology Group (ECOG) performance status of 0 or 1

- Life expectancy greater than or equal to 12 weeks.

Exclusion Criteria:

- Patients who have previously received a trial drug containing the core platform
antibody (eg, CVX-045, PF-04856884 (CVX-060), CVX-096, PF-05057459 (CVX-241), etc.).

- History of pathologic fistula, gastrointestinal perforation, or intra-abdominal
abscess within 6 months of therapy.

- Evidence of bleeding diathesis or coagulopathy.

- Major surgical procedure (eg, craniotomy), open biopsy, significant traumatic injury
within 28 days prior to therapy or anticipation of need for a major surgical
procedure during the course of the trial.

- Minor surgical procedures, fine needle aspiration or core biopsies within 7 days
prior to therapy.

- Serious non-healing wound, ulcer, or bone fracture.

- Active gastrointestinal bleeding, as evidenced by either hematemesis, hematochezia,
or melena in prior 6 months.

- Hemoptysis >½ teaspoon per day within 1 week of enrollment.

- National Cancer Institute-Common Terminology Criteria for Adverse Events [NCI CTCAE]
Grade 3 hemorrhage from any cause <4 weeks prior to enrollment.

- Participation in any investigational drug study within 28 days prior to study
therapy.

- Evidence of preexisting uncontrolled hypertension

- Clinically significant cardiovascular disease within the 12 months prior to starting
trial treatment

- Prolongation of the QT interval corrected [QTc] interval to >450 msec for men or >470
msec for women.

- History of allergic or anaphylactic reaction to any therapeutic or diagnostic
monoclonal antibody or IgG-fusion protein.

Exclusion Criteria Specific for Primary Cohort

- Prior therapy with bevacizumab or other anti-Vascular Endothelial Growth Factor
[VEGF] agents for the treatment of GBM.

Exclusion Criteria Specific for Exploratory Cohort

- Patients discontinued from prior bevacizumab or anti-VEGF agents due to toxicity.

- Patients who have failed 2 prior anti-VEGF therapies.