Maintenance Therapy With Sunitinib or Observation in Metastatic Pancreatic Cancer

DISEASE CHARACTERISTICS: * Pathologically confirmed metastatic pancreatic adenocarcinoma * Stage IV disease * Received chemotherapy for a duration of 6 months * No progressive disease for ≥ 6 months since beginning of induction chemotherapy (irrespective of regimen and response: stable disease, partial response, or complete response) demonstrated by the following: * Two consecutive CT or MR scans separated by ≥ 6 weeks * Normal or no CA19.9 increase \> 20% during the last month PATIENT CHARACTERISTICS: * Karnofsky Performance Status 50-100% * Adequate bone marrow, liver, and kidney function * Normal thyroid gland function (euthyroid) * Not pregnant or nursing * No duodenal, gastric, or intestinal infiltration * Able to take oral medication * None of the following conditions related to cardiac disease, failure, or vascular disease including any of the following: * QTc interval prolongation * Congestive heart failure * Serious cardiac arrhythmias * Active coronary artery disease * Myocardial infarction * Ischemia * Cerebrovascular accident * Evidence of pre-existing uncontrolled hypertension * No other malignancies except surgically cured carcinoma in situ of the cervix, basal or squamous cell carcinoma of the skin, or other adequately treated neoplasms for which the patient has been disease-free for ≥ 5 years PRIOR CONCURRENT THERAPY: * See Disease Characteristics * No other prior chemotherapy apart from first-line treatment for pancreatic cancer * More than 3 weeks and less than 8 weeks since prior chemotherapy (\> 1 week in the case of fluorouracil as continuous infusion or capecitabine) * No prior antiangiogenesis drugs, including any of the following: * Sunitinib malate * Sorafenib * Bevacizumab * AZD2171 * Vatalanib * VEGF trap * Pazopanib * More than 1 month since prior major surgical procedure and completely recovered * More than 7-12 days since prior and no concurrent drugs that are known CYP3A4 inhibitors * No concurrent drugs with potential anti-arrhythmic activity * No concurrent thrombolytic agent at therapeutical dose * No concurrent treatment with other experimental drugs