Inclusion Criteria:

1. Patients must have histologically or cytologically confirmed metastatic or recurrent
head and neck squamous cell carcinoma from the primary lesions and/or lymph nodes of
the oral cavity, oropharynx, hypopharynx, or larynx.

2. Patients must have measurable disease, defined as at least one lesion that can be
accurately measured in at least one dimension (longest diameter to be recorded) as
>/= 20 mm with conventional techniques or as >/= 10 mm with spiral CT scan.

3. Patients have received one or more chemotherapy regimens.

4. Age >/= 18 years.

5. Life expectancy of greater than 3 months.

6. No acute intercurrent illness or infection.

7. ECOG performance status /= 60%)

8. Laboratory parameters: white blood count (WBC) >3,000/mL; Neutrophils >1,500/mL;
Hemoglobin >8g/dL; Platelets >100,000/mL; Bilirubin <1.5 times the upper limit of
normal (ULN); Serum creatinine: within normal institutional limits; aspartate
aminotransferase (AST or SGOT) and alanine aminotransferase (ALT or SGPT) < 3 times
institutional ULN if alkaline phosphatase is < ULN, except in known hepatic
metastasis, wherein ALT/AST may be
9. Creatinine clearance: The standard Cockcroft and Gault formula or the measured
glomerular filtration rate (GFR) using the appropriate radiolabeled method (51-CrEDTA
or Tc99m-DTPA) must be used to calculate CrCl for enrollment or dosing. The same
method used at baseline should be used throughout the study. No dosage adjustment is
needed in patients with CrCl >/= 45 mL/min.

10. Patients with a history of non-melanoma skin cancer, or other malignancies treated 5
years or more prior to the current tumor, from which the patient has remained
continually disease-free, are eligible.

11. Ability to understand and the willingness to sign a written informed consent
document.

Exclusion Criteria:

1. Acute intercurrent illness or infection

2. Uncontrolled intercurrent illness including, but not limited to, ongoing or active
infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac
arrhythmia, or psychiatric illness/social situations that would limit compliance with
study requirements

3. Patients who are receiving any other investigational agents

4. Patients who have known brain metastases

5. Patients who have signs or symptoms of acute infection requiring systemic therapy.

6. Patients having a history of non-melanoma skin cancer, or other malignancies, treated
less than 5 years or more prior to the current tumor

7. Patients requiring total parental nutrition with lipids.

8. Patients exhibiting confusion, disorientation, or having a history of major
psychiatric illness that may impair the understanding of the informed consent.

9. Patients refusing to sign the informed consent.

10. Histology other than squamous cell carcinoma.

11. Inability or unwillingness to take folic acid or vitamin B12 supplementation

12. Inability to take corticosteroids

13. Inability to interrupt aspirin or other nonsteroidal anti-inflammatory agents for a
5-day period (for short-acting NSAIDs) or 8-day period (for long-acting NSAIDs, such
as piroxicam).