Gemcitabine Hydrochloride and Tanespimycin in Treating Patients With Stage IV Pancreatic Cancer

Inclusion Criteria: * Histologically or cytologically confirmed pancreatic adenocarcinoma * Clinical stage IV disease * No known brain metastases * ECOG performance status 0-2 * Life expectancy ≥ 12 weeks * Absolute Neutrophil Count (ANC) ≥ 1,500/mm³ * Platelet count ≥ 100,000/mm³ * Total bilirubin normal * Aspartate aminotransferase (AST) ≤ 2.5 times upper limit of normal (ULN) * Alkaline phosphatase ≤ 2 times ULN (5 times ULN if liver metastases are present) * Creatinine normal * Not pregnant or nursing * Negative pregnancy test * Fertile patients must use effective contraception * Ejection fraction \> 40% by echocardiogram * Patients who received prior anthracyclines must have a normal ejection fraction by echocardiogram * Corrected QT interval (QTc) \< 500 msec * Pulse oximetry \> 88% on room air at rest and after gentle exercise (according to Group Medicare Guidelines) * No history of allergic reactions attributed to compounds of similar chemical or biologic composition to tanespimycin (17-AAG) or gemcitabine hydrochloride * No known allergy to eggs * No concurrent uncontrolled illness including, but not limited to, any of the following: * Ongoing or active infection * Symptomatic congestive heart failure * Unstable angina pectoris * Cardiac arrhythmia * Psychiatric illness/social situations that would limit compliance with study requirements * No active ischemic heart disease within the past 12 months * No history of uncontrolled dysrhythmias * No congenital long QT syndrome * No left bundle branch block * No other significant cardiac disease, including any of the following: * New York Heart Association class III or IV heart failure * Myocardial infarction within the past year * Poorly controlled angina * Uncontrolled dysrhythmias * History of serious ventricular arrhythmia (ventricular tachycardia or ventricular fibrillation ≥ 3 beats in a row) * No clinically significant interstitial lung disease * No symptomatic pulmonary disease requiring medication, including any of the following: * Dyspnea * Dyspnea on exertion * Paroxysmal nocturnal dyspnea * Significant pulmonary disease requiring oxygen\*, including chronic obstructive/restrictive pulmonary disease * No pulmonary or cardiac symptoms ≥ grade 2 * No history of cardiac or pulmonary toxicity after receiving anthracyclines (e.g., doxorubicin hydrochloride, daunorubicin hydrochloride, mitoxantrone hydrochloride, bleomycin, or vincristine) * No prior chemotherapy for metastatic disease * No prior radiotherapy to the chest * No prior radiotherapy that potentially included the heart in the field (e.g.,mantle radiotherapy) * More than 3 months since prior adjuvant chemotherapy or chemotherapy for locally advanced disease * More than 3 weeks since prior radiotherapy * No concurrent medications that prolong or may prolong QTc * No concurrent antiarrhythmic drugs * No concurrent prophylactic colony-stimulating factors * No other concurrent investigational agents * No other concurrent anticancer therapy