Inclusion Criteria:

- Diagnosis of NSCLC Stage IIIB not amenable to curative treatment or Stage IV.

- No prior chemotherapy for lung cancer.

- Patients must have at least one uni-dimensionally measurable lesion.

- Prior radiation therapy to less than 25% of bone marrow, whole pelvis not allowed.
Radiation must be completed at least 4 weeks prior to study enrollment.

Exclusion Criteria:

- Treatment with any drug within the last 30 days that has not received regulatory
approval.

- Serious cardiac condition.

- Serious medical disorder in addition to NSCLC that would make it difficult for the
patient to complete the study.

- Inability or unwillingness to take folic acid or Vitamin B12 supplementation.

- Presence of fluid retention that cannot be controlled by drainage.