Pemetrexed as Second-Line Therapy in Treating Patients With Hormone Refractory Prostate Cancer

Inclusion Criteria: Histologically documented adenocarcinoma of the prostate Clinically refractory or resistant to hormone therapy as assessed by progression following at least one hormonal therapy (orchiectomy or luteinizing hormone-releasing hormone (LHRH) agonist) One prior taxane based chemotherapy regimen for HRPC Documented progression of disease after one taxane based prior chemotherapy regimen for HRPC. Progression is defined as at least one of the following: An increase in PSA > 50% over nadir value on prior Taxane-based therapy Progression of measurable disease as defined by RECIST Progression of bone disease as defined by the appearance of one or more new bone lesions or worsening symptoms Orchiectomy or testosterone levels < 50 ng/dL maintained by LHRH agonist Prior chemotherapy, or other experimental anticancer agents must be completed > 4 weeks prior to being registered for protocol therapy Palliative radiotherapy must be completed at least 14 days prior to registration. Exclusion Criteria: Intravenous radio-isotopes therapy must be completed at least 6 weeks prior to registration No brain metastasis that are untreated and/or not controlled and/or still requiring corticosteroids No history of other malignancies within 5 years prior to being registered for protocol therapy, except for adequately treated basal or squamous cell skin cancer No history of uncontrolled psychiatric illness or serious systemic disease, including active infection, uncontrolled hypertension No surgery or significant traumatic injury within 21 days prior to being registered for protocol therapy Patients must be willing to interrupt aspirin or other non-steroidal anti-inflammatory agents for a 5-day period (8 day period for long acting agents such as piroxicam) Patients must be willing to take folic acid or vitamin B12 supplementation