This phase II study is evaluating the activity of Pemetrexed in patients diagnosed with low risk Gestational Trophoblastic Tumor (GTT) that have failed prior treatment.

Inclusion Criteria:

• Persistent or recurrent low risk Gestational Trophoblastic Tumor (GTT)
• WHO score 2-6 (re-evaluated at the time of relapse
• Histologically confirmed complete or partial moles on initial evacuation
• Patients with mild to moderate renal insufficiency should avoid taking NSAIDs with short elimination half-lives for a period of 2 days before, the day of, and 2 days following administration of pemetrexed.
• All patients taking NSAIDs with longer half-lives, should interrupt dosing for at least 5 days before, the day of, and 2 days following pemetrexed administration.
• Folic Acid (350-1000 micrograms) must be given daily beginning approximately 5-7 days prior to first dose of pemetrexed and continuing daily until 3 weeks after the last dose of study therapy.
• Vitamin B12 (1000 micrograms) will be administered as an intramuscular injection approximately 1 to 2 weeks prior to first dose of pemetrexed and repeated approximately every 9 weeks until 3 weeks after the last dose of study therapy.

Exclusion Criteria:

• Previous treatment that included chemotherapy other than actinomycin -D or methotrexate (+/- folinic acid).
• Patients with more than 8 metastatic lesions identified
• Patients with metastases to liver, spleen, brain, kidney or GI tract