Study of Pemetrexed for Second-Line Pancreas Cancer

Inclusion Criteria: * Histologically confirmed adenocarcinoma of the pancreas * Prior treatment for distant or locally advanced disease with gemcitabine-based therapy * Measurable or evaluable disease * ECOG performance status 0-2 * Adequate hematological parameters * Adequate baseline liver function * At least 28 days from any major surgery * At least 2 weeks from the last radiation treatment * Must have recovered from reversible toxicities of prior chemotherapy * Must be able to discontinue any nonsteroidal anti-inflammatory medications * Must be willing to receive intramuscular vitamin B12 shots and take oral folate supplements Exclusion Criteria: * Any prior treatment with pemetrexed * More than one prior chemotherapy regimen * HIV positive on antiretroviral therapy * Pregnant or lactating * Prior organ allograft * On concurrent antitumor therapy including radiation therapy or other chemotherapies * Creatinine clearance 45 ml/min or less * Absolute neutrophil count \< 1500 * Platelets \< 75,000 * Bilirubin \> 1.5 times the upper limit of normal * Transaminases \> 3 times the upper limit of normal except in known liver metastasis wherein they may be \</= 5 times upper limit of normal * Clinically significant ascites or pleural effusion that cannot be drained * Any medical or psychiatric condition that may interfere with the ability to comply with protocol treatment