Primary Objectives

Cohort A -- monotherapy:

To determine the efficacy of AMG 386 in participants with recurrent glioblastoma (GBM) as measured by 6-month progression-free survival (PFS6)

Cohort B - combination therapy:

Phase I To determine the maximum tolerated dose of AMG 386 in combination with bevacizumab given at 10mg/kg every 2 weeks in participants with recurrent glioblastoma.

Phase II To determine the efficacy of AMG 386 plus bevacizumab in participants with recurrent glioblastoma (GBM) as measured by 6-month progression-free survival (PFS6).

Secondary Objectives:

To evaluate radiographic response in both cohort populations. To evaluate overall survival in both cohort populations. To assess time-to-progression in both cohort populations. To investigate the safety profile in both cohort populations.

Exploratory Objectives:

To evaluate expression of factors associated with tumor angiogenesis using a multiples cytokine assay among participants undergoing therapy with AMG 386 with response to therapy and development of resistance.

This is an open-label Phase I/II study of AMG 386 monotherapy and AMG 386 in combination with bevacizumab. Two cohorts will accrue and will be assessed sequentially. Each cohort will enroll participants with recurrent GBM. Cohort A will assess recurrent GBM participants who receive AMG 386 monotherapy at 30 g/kg every week. (Cohort A initially accrued at a dose of 15mg/kg, but this was increased to 30 mg/kg every week following an amendment). Cohort B will assess recurrent GBM participants who receive weekly AMG 386 plus bi-weekly bevacizumab (10mg/kg). Cohort B will start with a Phase I component to determine the MTD of AMG 386 that is safe when used in combination with bevacizumab. AMG 386 is administered intravenously, and, when used in combination with intravenous bevacizumab, will be administered first.

Patients will be required to come to the clinic weekly for study drug administration.

For study purposes, a cycle of therapy will be 4 weeks. Treatment will continue until either evidence of progressive disease, unacceptable toxicity, non-compliance with study follow-up, or withdrawal of consent.

The estimated rate of accrual is 60 participants per year. The estimated date of accrual completion is 1.5 years from study initiation. The estimated date of study completion will be approximately 12 months from enrollment of the last study participant.

Inclusion Criteria

• Signed informed consent approved by the Institutional Review Board prior to participant entry
• Age ≥ 18 years.
• Karnofsky ≥ 70%
• Participant must be able and willing to comply with study and/or follow-up procedures Participants must have histologically confirmed diagnosis of GBM patients with either grade III or IV malignant glioma are eligible to the Phase I portion of the study) and radiographic evidence of recurrence or disease progression (defined as either a greater than 25% increase in the largest bidimensional product of enhancement, a new enhancing lesion, or significant increase in T2 FLAIR) following prior therapy (i.e. chemotherapy, XRT, other investigational therapies).
• No more than 2 prior episodes of progressive disease (patients with more than 2 prior episodes of progressive disease are eligible for the Cohort B, Phase I portion of this study)
• An interval of at least 4 weeks (to start of study agent) between prior surgical resection or one week from stereotactic biopsy
• An interval of at least 12 weeks (to start of study agent) from the end of prior radiotherapy unless there is a new area of enhancement consistent with recurrent tumor outside of the radiation field, or there is histological confirmation of unequivocal tumor progression
• From the projected start of scheduled study treatment, the following time periods must have relapsed: 4 weeks (or 5 half lives, whichever is shorter) from any investigational agent, 4 weeks (or 5 half lives, whichever is shorter) from cytotoxic therapy (except 23 days for temozolomide and 6 weeks from nitrosoureas), 6 weeks from antibodies (or 5 half lives, whichever is shorter), or 4 weeks (or 5 half lives, whichever is shorter) from other anti-tumor therapies.
• Participants must have recovered to a grade 0 or 1 from the toxic effects of prior therapy (with the exception of lymphopenia, which is common after therapy with temozolomide, and alopecia).
• No evidence of hemorrhage on the baseline MRI or CT scan other than those that are ≤ grade 1 and either post-operative or stable on at least two consecutive scans. Clinical Labs - performed within 14 days prior to enrollment
• Hematocrit ≥ 29%, ANC ≥ 1,000 cells/μl, platelets ≥ 100,000 cells/μl ;
• Serum creatinine ≤ 1.5 mg/dl, serum SGOT and bilirubin ≤ 1.5 times upper limit of normal;
• PTT or aPTT ≤ 1.5 times upper limit of normal and INR ≤ 1.5
• Calculated creatinine clearance ≥ 40 mL/min according to the Cockcroft-Gault formula OR per 24 hour urine collection
• Urinary protein quantitative value of < 30 mg/dL in urinalysis or <1+ on dipstick, unless quantitative protein is < 1000 mg in a 24 hour urine sample;
• Participants of child-bearing potential who have not undergone a bilateral salpingo-oophorectomy and are sexually active must consent to use an accepted and highly effective non-hormonal method of contraception (i.e. double barrier method [e.g., condom plus diaphragm]) from signing the informed consent through 6 months after last dose of study drug.

Exclusion Criteria:

• Prior anti-angiogenic therapy targeting VEGF or VEGF receptor including prior bevacizumab.
• Prior AMG 386 therapy or other molecules that inhibit the angiopoietins or Tie2 receptor.
• Co-medication that may interfere with study results; e.g. immunosuppressive agents other than corticosteroids.
• Active infection requiring intravenous antibiotics
• Current or within 30 days prior to enrollment treatment with immune modulators such as systemic cyclosporine and tacrolimus.
• Current us of warfarin sodium or any other Coumadin-derivative anticoagulant. Participant must be off Coumadin-derivative anticoagulants for at least seven days prior to starting study drug. ow molecular weight heparin is allowed.
• Current, recent (within 4 weeks of the first infusion of this study), or planned participation in an experimental drug study other than supportive care or epidemiologic studies.
• Herbal preparations/medications are not allowed throughout the study. These herbal medications include, but are not limited to: St. John's wort, Kava, ephedra (ma huang), gingko biloba, dehydroepiandrosterone (DHEA), yohimbe, saw palmetto, ginseng. Participants should stop using any herbal medications 7 days prior to first dose of study drug.
• History of clinically significant bleeding within 6 months of enrollment
• History of allergic reactions to bacterially produced proteins
• Known hypersensitivity to any component of bevacizumab (cohort B only)
• Known sensitivity to any of the products to be administered during dosing
• History of venous or arterial thromboembolism within 12 months prior to enrollment.
• Severe hepatic insufficiency (ongoing grade 3 or greater hepatic adverse events) or known active chronic hepatitis.
• Inadequately controlled hypertension (defined as systolic blood pressure >140 and/or diastolic blood pressure > 90 mmHg). The use of anti-hypertensive medications to control hypertension is permitted.
• Any prior history of hypertensive crisis or hypertensive encephalopathy
• Clinically significant cardiovascular disease within 12 months prior to enrollment, including myocardial infarction, unstable angina, grade 2 or greater peripheral vascular disease, cerebrovascular accident, transient ischemic attack, congestive heart failure, or arrhythmias not controlled by outpatient medication, percutaneous transluminal coronary angioplasty/stent.
• Evidence of bleeding diathesis or coagulopathy
• Major surgical procedure, open biopsy, or significant traumatic injury within 28 days prior to study enrollment or anticipation of need for major surgical procedure during the course of the study
• Core biopsy or other minor surgical procedure, excluding placement of a vascular access device, within 7 days prior to study enrollment.
• History of abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within 6 months prior to study enrollment.
• Serious, non-healing wound, ulcer (including gastrointestinal), or bone fracture.
• Any condition which in the investigator's opinion makes the subject unsuitable for study participation.
• Pregnant (positive pregnancy test) or lactating. Refusal or inability to use highly effective means of contraception (men and women) in participants of child-bearing potential.

Assessed each treatment cycle (1 cycle = 28 days) from time of first dose and up to day 30 post-treatment. Treatment duration in cycles was a median (range) of 1 (1-2) Cohort A and 4 (1-20) Cohort B.

Maximum grade toxicity by type was first calculated. Serious AEs were defined as events with AMG386 and/or bevacizumab treatment-attribution of at least possibly and causing a hospitalization, deemed serious by the treating investigator or grade 5 events per CTCAE v4. Other AEs were defined as events with AMG386 and/or bevacizumab treatment-attribution of at least possibly and not requiring a hospitalization or deemed non-serious by treating investigator.