Pralatrexate and Fluorouracil in Treating Patients With Recurrent Solid Tumors

Inclusion Criteria: * Cancer patients who have failed standard therapy for their disease or for whom no such therapy is available are eligible, for which 5-fluoropyrimdines, including 5-FU, or inhibitors of DHFR (dihydrofolate reductase), including pralatrexate, have the potential for therapeutic benefit * Objectively measurable disease is preferred, but not required * Performance status of 0-2 (Eastern Cooperative Oncology Group \[ECOG\]) * Prior treatment: * The patient should have recovered from the toxicities associated with prior chemotherapy (at least 3 weeks from prior therapy) * At least two or more weeks should have elapsed since any radiotherapy, and the patient should have recovered from the toxicity associated with such therapy * If a recent surgical procedure has been performed, the patient should have recovered from the surgery prior to entering this trial * Absolute granulocyte count of 1500 per mcL or greater * Platelet count of 100,000 per mcL or greater * Serum bilirubin less than 1.5 times the upper limits of the institutional normal * Serum creatinine less than the upper limits of normal * The patient must willingly give signed informed consent Exclusion Criteria: * Pregnant women and nursing mothers are ineligible; eligible patients of reproductive potential should use adequate contraception if sexually active * Serious concurrent medical illness which would jeopardize the ability of the patient to receive the chemotherapy program outlined in this protocol with reasonable safety * Patients with active infections requiring intravenous antibiotic therapy are not eligible until the infection has resolved * Patients who are human immunodeficiency virus (HIV) antibody positive and are receiving highly active antiretroviral therapy (HAART) are ineligible * Concomitant administration of nonsteroidal anti-inflammatory drugs (NSAIDs) and trimethoprim/sulfamethoxazole will not be allowed