Inclusion criteria:

1. You must be at least 18 years old
2. You must have been diagnosed with non-squamous non-small cell lung cancer (NSCLC)
3. You must have had no prior systemic anticancer therapy for lung cancer
4. You must live close enough to the study doctor to be able to visit regularly for follow up
5. You must have signed informed consent form indicating your willingness to take part in this study
6. Your laboratory and medical history and tests must meet study requirements

Exclusion criteria:

1. Treatment within the last 30 days with a drug that has not received regulatory approval for any indication at the time of study entry
2. Prior radiotherapy and surgery should be completed at least 4 weeks prior to initiation of treatment
3. Serious concomitant systemic disorder (e.g., active infection including human immunodeficiency virus, or unstable cardiovascular disease)
4. Prior malignancy other than NSCLC, carcinoma in situ of the cervix, or nonmelanoma skin cancer unless treated at least 5 years previously with no subsequent evidence of recurrence
5. Brain metastasis
6. Presence of clinically significant (by physical exam) third-space fluid collections, for example, ascites or pleural effusions that cannot be controlled by drainage or other procedures prior to study entry
7. Significant weight loss (greater than 10%), over the previous 6 weeks before study entry
8. Concurrent administration of any other antitumor therapy
9. Inability to interrupt aspirin or other non-steroidal anti-inflammatory agents for a 5-day period (8-day period for long-acting agents such as piroxicam)
10. Inability or unwillingness to take folic acid, dexamethasone (or equivalent) or vitamin B12 supplementation
11. Pregnancy or breast-feeding
12. You are allergic to pemetrexed