Temozolomide and Pazopanib Hydrochloride in Treating Patients With Advanced Pancreatic Neuroendocrine Tumors That Cannot Be Removed By Surgery

Inclusion Criteria: * Patients must have histologically confirmed islet cell carcinoma (PNET) not amenable to surgical resection * Patients may have had 0-2 prior therapies; prior chemoembolization or local ablative therapies are permitted if completed \>= 6 weeks prior to study enrollment * Patients must have an Eastern Cooperative Oncology Group (ECOG) performance status =\< 2 * Patients must have a life expectancy \> 3 months * Patients must have radiographically measurable disease as defined by Response Evaluation Criteria in Solid Tumors (RECIST) version 1.1 criteria * Patients' baseline blood pressure must be adequately controlled with or without antihypertensive medications prior to enrollment (systolic \< 140 mmHg, diastolic \< 90 mmHg) * Patients must have left ventricular ejection fraction (LVEF) \>= 50 as measured by echocardiogram or multi gated acquisition scan (MUGA) * Absolute neutrophil count (ANC) \>= 1,500/µL * Platelets \>= 100,000/µL * Hemoglobin \>= 9.0 g/dL * Total bilirubin =\< 2 mg/dL or =\< 1.5 times upper limit of normal (ULN) * Aspartate aminotransferase (AST) (serum glutamic oxaloacetic transaminase \[SGOT\]) and alanine aminotransferase (ALT) (serum glutamic pyruvate transaminase \[SGPT\]) =\< 5 times ULN * International normalized ratio (INR) =\< 1.2 times upper limit of normal (ULN); subjects receiving anticoagulant therapy are eligible if their INR is stable and within the recommended range for the desired level of anticoagulation * Activated …