The purpose of this study is to determine the effects (good and bad) the combination of carboplatin and pemetrexed have on patients with recurrent ovarian, peritoneal, or fallopian tube cancer.

• Before patients receive any chemotherapy treatments they will be given three medications to prevent side effects from the chemotherapy drugs. These medications are vitamin B12, folic acid and dexamethasone.
• Chemotherapy treatments will be given intravenously in the outpatient clinic. Pemetrexed will be given first and will take 10 minutes to infuse followed by carboplatin which will take 30-45 minutes to infuse. These treatments will be repeated once every three weeks for 6 cycles of chemotherapy (18 weeks).
• Before each chemotherapy treatment the following tests and procedures will be performed: physical exam and medical history; evaluation of ability to undertake daily activities; and blood tests.
• After every 2 cycles of chemotherapy (every 6 weeks) patients will have a CT or MRI scan to measure how well their cancer is responding to treatment.
• The study treatment will last for 6 cycles of chemotherapy as long as the tumor does not grow and the patient isn't experiencing any severe side effects.

Inclusion Criteria:

• Diagnosis of platinum-sensitive recurrence of epithelial ovarian cancer, primary peritoneal cancer, or fallopian tube cancer
• The following histologic subtypes are eligible: papillary serous, endometrioid, mucinous, clear cell, adenocarcinomas, transitional, and mixtures of the above.
• At least one measurable lesion according to RECIST criteria via CT or MRI scan
• Received a platinum-containing regimen at initial diagnosis
• ECOG performance status of 0,1 or 2
• 18 years of age or older
• Life expectancy of greater than 12 weeks
• WBC > 1,500/mm3
• Neutrophils > 1,500/mm3
• Platelets > 100,000/mm3
• Total Bilirubin < 1.5 ULN
• Calculated creatinine clearance > 45 ml/min
• ALT/AST < 3 x ULN (no liver mets) ALT/AST < 5 x ULN (with liver mets)
• Complete recovery from completion of previous chemotherapy or biologic therapy
• Negative pregnancy test and agree to practice effective method of birth control

Exclusion Criteria:

• Patients with sarcomatous, stromal, or germ cell elements
• Prior pelvic radiotherapy > 25% of bone marrow
• Uncontrolled medical problem that in the opinion of the investigator would preclude safe administration of the study drugs
• Past history of bone marrow transplantation or stem cell support
• Known history of CNS metastasis unless the patient has had treatment with surgery or radiation therapy, is neurologically stable, and does not require oral or intravenous corticosteroids or anticonvulsants
• Prior malignancy except adequately treated carcinoma in situ of the uterine cervix, incidental stage I endometrial cancer, basal cell or squamous cell skin cancer or breast cancer (invasive or ductal carcinoma in situ) of which the patient has been disease-free for at least five years
• Routine prophylactic use of G-CSF or GM-CSF or blood transfusions within 2 weeks
• Clinically significant cardiac disease as defined by: history of unstable angina within 6 months; history of symptomatic ventricular arrhythmias; history of congestive heart failure; history of myocardial infarction within 6 months
• Uncontrolled hypercalcemia or diabetes mellitus
• Any signs of intestinal obstruction with bowel function and/or nutrition
• Grade 2 or greater peripheral neuropathy
• Participation in an investigational study within three weeks
• History of anaphylactic shock to prior platinum chemotherapy
• History of psychiatric disability or other central nervous system disorder