Inclusion Criteria:

- Stage IIIB or stage IV NSCLC

- Stable disease or a clinical response following first-line treatment, consisting of
either chemotherapy alone or chemotherapy and radiotherapy. Patients must have
completed the first-line treatment at least 3 weeks prior to study entry

- ECOG performance status of ≤2

- Ability to understand and willingness to sign a written informed consent

Exclusion Criteria:

- Received immunotherapy within 4 weeks prior to study entry

- Received immunosuppressive drugs within 3 weeks prior to study entry

- Patients with known brain metastases

- Past or current history of neoplasm other than lung carcinoma, except for curatively
treated non-melanoma skin cancer, in situ carcinoma of the cervix or other cancer
curatively treated and with no evidence of disease for at least 5 years

- Autoimmune disease or immunodeficiency

- Clinically significant hepatic, renal or cardiac dysfunction

- Patients with clinically significant active infection

- Pregnant or breast feeding women, women of childbearing potential, unless using
effective contraception as determined by the investigator