Inclusion Criteria:

- Age >= 18 years

- Histological diagnosis of glioblastoma multiforme (GBM) documented by surgical
resection or biopsy.

- They should be patients in a first relapse treated with radiotherapy and chemotherapy
and chemotherapy based on temozolomide 150-200 mg/m2 on days 1 to 5 every 28 days
(Stupp regimen) for at least three cycles. At least 4 weeks must have lapsed since
previous chemotherapy and 3 months since the last dose of radiotherapy.

- Use of an effective contraceptive method by patients and their partners.

- Stable or decreasing corticosteroid dose for the five days prior to study entry

- Adequate hematological function

- Adequate liver function

- Adequate kidney function

Exclusion Criteria:

- Signs of recent bleeding at the MRI of the brain. However, patients with clinically
asymptomatic presence of hemosiderin, resolving bleeding changes related to surgery,
and presence of punctate hemorrhage in the tumor will be allowed to participate in
the study.

- Prior treatment with bevacizumab

- Poorly controlled arterial hypertension

- History of hypertensive crises or hypertensive encephalopathy

- New York Health Association (NYHA) Class II or higher congestive heart failure

- History of myocardial infarction or unstable angina pectoris within six months of
study entry

- History of stroke or TIA within six months of study entry

- Significant vascular disease within six months of study entry

- History of hemoptysis > grade 2 according to the NCI CTC criteria within one month of
study entry

- Evidence of bleeding diathesis or coagulopathy (in the absence of therapeutic
anticoagulation)

- Major surgery, open biopsy, intracranial biopsy, ventriculoperitoneal shunt, or major
traumatic lesion within 28 days of study entry.

- Core needle biopsy (excluding intracranial biopsy) or other minor surgery within
seven days of randomization. Placement of a central vascular access device (CVAD) if
performed in the two days prior to bevacizumab administration

- History of abdominal fistula or gastrointestinal perforation within six months of
study entry

- History of intracranial abscess within six months of randomization

- Any prior malignant neoplasm treated with curative intent in the five years prior to
study entry, except for adequately controlled limited basal cell carcinoma of the
skin, squamous cell carcinoma of the skin, or carcinoma in situ of the cervix

- Patients with any other metabolic or psychological disease

- Hypersensitivity to products derived from Chinese hamster ovary cells or to other
humanized or recombinant human antibodies