Imatinib Mesylate With or Without Bevacizumab in Treating Patients With Metastatic or Unresectable Gastrointestinal Stromal Tumor

Criteria:

• Histologically confirmed gastrointestinal stromal tumor (GIST)
• Metastatic or unresectable disease
• Determined to be unresectable for cure
• Measurable and/or nonmeasurable disease by MRI or CT scan
• No known brain metastasis
• Zubrod performance status 0-3
• Platelet count >= 100,000/mm^3
• Absolute neutrophil count >=1,000/mm^3
• Hemoglobin >= 9 g/dL (transfusion allowed)
• Bilirubin =< 2.0 times upper limit of normal (ULN)
• SGOT/SGPT =< 2.5 times ULN (5 times ULN with liver involvement)
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective barrier contraception during and for up to 6 months after completion of study treatment
• No cerebrovascular accident, transient ischemic attack, myocardial infarction, or unstable angina within the past 6 months
• No serious cardiac arrhythmia requiring medication
• No New York Heart Association class II-IV congestive heart failure
• No clinically significant peripheral vascular disease
• No abdominal fistula, gastrointestinal perforation, or intra-abdominal abscess within the past 28 days
• No contraindication to oral medications (e.g., severe dysphagia)
• G- or J-tubes allowed
• No history of hypertension unless well controlled (i.e., blood pressure < 160/90 mm Hg) and on a stable regimen of antihypertensive therapy
• No serious nonhealing wound, ulcer, or bone fracture
• No other prior malignancy except for any of the following: adequately treated basal cell or squamous cell skin cancer; in situ cervical cancer; adequately treated stage I or II cancer that is currently in complete remission; any other cancer for which the patient has been disease free for >= 5 years
• No significant traumatic injury in the past 28 days
• Recovered from prior therapy
• At least 28 days since prior chemotherapy
• At least 28 days since prior radiotherapy
• Evidence of progressive disease within the radiation field or disease outside the radiation field
• No prior bevacizumab or other agents targeting vascular endothelial growth factor (VEGF), VEGF receptor, or platelet-derived growth factor receptor (PDGFR) for advanced disease
• These agents may have been used in the adjuvant setting provided no recurrence for >= 12 months after completion of therapy
• More than 28 days since prior major surgery or open biopsy
• No anticipated need for major surgery
• More than 7 days since prior fine-needle aspiration or core biopsies
• More than 7 days since prior procedure to place a portacath
• No other concurrent anticancer biologic agents, chemotherapy, radiotherapy, or any other anticancer agents
• No concurrent therapeutic warfarin for anticoagulation
• Concurrent low-molecular weight heparin or other agents for therapeutic anticoagulation or mini-dose warfarin for prophylaxis allowed
• No other concurrent investigational agents
• Creatinine =< 1.5 times ULN
• Urine protein:creatinine ratio < 1
• INR =< 1.5
• PTT normal