DISEASE CHARACTERISTICS:

• Histologically confirmed cancer of the urothelium (renal pelvis, ureter, bladder, or urethra)

  • Any of the following types:

    • Transitional cell carcinoma (TCC)
    • Mixed histologies containing a component of TCC
    • Non-TCC of the urothelium (renal pelvis, ureter, bladder, or urethra)
• Progressing regional or metastatic disease
• Measurable disease
• No clinical evidence of CNS metastases
• No evidence of clinically significant (by physical exam or plain film) third-space fluid collections (pleural effusions or ascites)

PATIENT CHARACTERISTICS:

Age

• 18 and over

Performance status

• ECOG 0-2

Life expectancy

• Not specified

Hematopoietic

• Granulocyte count at least 1,500/mm^3
• Platelet count at least 100,000/mm^3
• Hemoglobin at least 9 g/dL

Hepatic

• AST no greater than 3 times upper limit of normal (ULN)
• Bilirubin no greater than 1.5 times ULN

Renal

• Creatinine clearance at least 45 mL/min

Cardiovascular

• No history of severe cardiovascular disease (i.e., American Heart Association class III or IV heart disease)
• No uncontrolled congestive heart failure
• No ventricular dysrhythmias

Other

• Not pregnant or nursing
• Fertile patients must use effective contraception
• No active unresolved infection
• No other prior malignancy unless curatively treated and disease free for an appropriate (disease-specific) period of time
• Able and willing to receive folic acid and cyanocobalamin supplementation

PRIOR CONCURRENT THERAPY:

Biologic therapy

• No prior systemic biologic response modifier therapy

Chemotherapy

• No prior systemic chemotherapy for metastatic disease
• More than 1 year since prior neoadjuvant or adjuvant chemotherapy

Endocrine therapy

• Not specified

Radiotherapy

• At least 4 weeks since prior radiotherapy and recovered
• No prior pelvic radiotherapy
• No concurrent radiotherapy

Surgery

• At least 4 weeks since prior major surgery and recovered

Other

• More than 7 days since prior parenteral antibiotics
• No salicylates for 2 days before, during, and for 2 days after administration of pemetrexed disodium
• No nonsteroidal anti-inflammatory drugs for at least 5 days before, during, and for 2 days after administration of pemetrexed disodium