Vorinostat With XRT and 5-FU for Locally Advanced Adenocarcinoma of the Pancreas

Inclusion Criteria: * Histologically or cytologically proven adenocarcinoma of the pancreas * Evaluable disease * Must have received 3-4 months of gemcitabine-based chemotherapy and have had stable disease by RECIST criteria. Regimens include: * gemcitabine alone * gemcitabine and erlotinib * gemcitabine and oxaliplatin * gemcitabine and cisplatin * gemcitabine and capecitabine * 18 years of age or older * Life expectancy of greater than 4 months * ECOG Performance Status 0-1 * Normal organ and marrow function as outlined in the protocol * Ability to drink at least 2 liters of fluid daily * Women of child-bearing potential and men must agree to use adequate contraception prior to study entry and for the duration of study participation * Patients must be able to swallow capsules Exclusion Criteria: * Chemotherapy within 3 weeks prior to entering the study or those who have not recovered from adverse events due to agents administered more than 4 weeks earlier * Participants may not be receiving any other study agents * Known distant metastases to any organ * History of allergic reactions attributed to compounds of similar chemical or biologic composition to vorinostat or 5-FU * Patients taking warfarin due to potential interactions of both 5-FU and vorinostat. Low molecular weight heparin should be substituted when appropriate * Patients who have received upper abdominal radiation therapy which fields would overlap with that determined necessary to treat the primary tumor. * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements * Pregnant or breastfeeding women * Individuals with history of a different malignancy are ineligible unless they are deemed by the investigator to be at low risk of recurrence of that malignancy. Patients may not have a concurrent second malignancy. * Active HIV or hepatitis * Prior exposure to HDAC inhibitor (except valproic acid, provided there is a 30 day washout period)