Inclusion Criteria:

- Receipt of concomitant or sequential chemoradiotherapy, consisting of a minimum of
two cycles of platinum-based chemotherapy and a minimum radiation dose of ≥ 50 Gy.
Subject must have completed the primary thoracic chemoradiotherapy at least 4 weeks
and no later than 12 weeks prior to randomization.

- Written informed consent given before any study-related activities are carried out.

- Histologically or cytologically documented unresectable stage III NSCLC. Cancer stage
must be confirmed and documented by CT-, MRI-, or PET scan.

- Documented stable disease or objective response, according to RECIST, after primary
chemoradiotherapy for unresectable stage III disease, within four weeks prior to
randomization.

- Receipt of concomitant or sequential chemoradiotherapy, consisting of a minimum of
two cycles of platinum-based chemotherapy and a minimum radiation dose of ≥ 50 Gy.

- ECOG performance status of 0 or 1.

- Adequate bone marrow function.

- ≥ 20 years of age.

Exclusion Criteria:

- Lung cancer-specific therapy (including surgery), other than primary
chemoradiotherapy. Note: exploratory surgery before study entry is allowed.

- Immunotherapy (e.g., interferons, tumor necrosis factor [TNF], interleukins, or
biological response modifiers [granulocyte macrophage colony stimulating factor
{GM-CSF}, granulocyte colony stimulating factor {G-CSF}, macrophage-colony
stimulating factor {M-CSF}], monoclonal antibodies) received within four weeks prior
to randomization.

- Malignant pleural/pericardial effusion or pleural dissemination or separate tumor
nodules in the same lobe at initial diagnosis and/or at study entry.

- Past or current history of neoplasm other than lung carcinoma, except for adequately
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 five years.

- Autoimmune disease.

- A recognized immunodeficiency disease including cellular immunodeficiencies,
hypogamma-globulinemia, or dysgammaglobulinemia; subjects who have hereditary or
congenital/acquired immunodeficiencies.

- Any preexisting medical condition requiring chronic steroid or immunosuppressive
therapy, including presence of diffuse radiation pneumonitis spreading out of the
involved field.

- Known Hepatitis B and/or C.

- Clinically significant hepatic dysfunction.

- Clinically significant renal dysfunction.

- Clinically significant cardiac disease.

- Splenectomy.

- Infectious process that, in the opinion of the investigator, could compromise the
subject's ability to mount an immune response.

- Pregnant or breast-feeding women. Subjects whom the investigator considers may be at
risk of pregnancy will have a pregnancy test performed per institutional standard.
Male and female subjects who have a reproductive ability, unless using effective
contraception as determined by the investigator throughout the study until at least 6
months after the last study treatment.

- Known drug abuse or alcohol abuse.

- Legal incapacity or limited legal capacity.