Tecemotide Following Concurrent Chemo-radiotherapy for Non-small Cell Lung Cancer

Inclusion Criteria: * Written informed consent, before any trial-related activities are carried out * Histologically or cytologically documented unresectable stage III NSCLC, including bronchioalveolar carcinomas. Cancer stage must be confirmed and documented by computed tomography (CT), magnetic resonance imaging (MRI) or positron emission tomography (PET) scan * Prior concurrent CRT which is defined as follows: * Minimum of 2 cycles of platinum-based chemotherapy * Radiotherapy with a total tumor dose greater than equal to (\>=) 60 Gray and a single fraction dose \>= 1.8 Gray * Overlap of radiotherapy with minimum 2 cycles of platinum-based chemotherapy (one cycle is defined as either 3 or 4 weeks depending on the chemotherapy regimen). A deviation of 2 to 3 days from an exact overlap is acceptable. Purely radiosensitizing doses of chemotherapy are not acceptable (for example \[e.g.\], daily low dose regimens; weekly carbo-platinum + paclitaxel regimens are allowed). * Subjects must have completed the primary thoracic CRT at least 4 weeks (28 days) and no later than 12 weeks (84 days) prior to randomization. Subjects who received prophylactic brain irradiation as part of primary CRT are eligible. * Documented stable disease or objective response, according to Response Evaluation Criteria in Solid Tumors (RECIST) 1.1, after primary concurrent CRT for unresectable stage III disease, within 4 weeks (28 days) prior to randomization * An Eastern Cooperative Oncology Group (ECOG) performance status of 0-1 * A platelet count, white blood cells (WBC) and hemoglobin value as defined in the protocol * Male or female, greater than or equal to 18 years of age * Other protocol defined inclusion criteria could apply Exclusion Criteria: * Undergone lung cancer specific therapy (including surgery) other than initial concurrent CRT * Received chemotherapy during radiotherapy in radiosensitizing doses only (e.g., daily low dose regimens; weekly carbo-platinum + paclitaxel regimens are allowed). * Metastatic disease * Malignant pleural effusion at initial diagnosis, during initial CRT, and/or at trial entry * 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 * A recognized immunodeficiency disease including human immunodeficiency virus (HIV) infection and other cellular immunodeficiencies, hypogammaglobulinemia or dysgammaglobulinemia; subjects who have hereditary, congenital or acquired immunodeficiencies * Splenectomy * Any preexisting medical condition requiring chronic systemic steroid or immunosuppressive therapy (steroids for the treatment of radiation pneumonitis are allowed) * Receipt of immunotherapy (as defined in the protocol) within 4 weeks prior to randomization * Receipt of investigational systemic drugs (including off-label use of approved products) within 4 weeks prior to randomization * Autoimmune disease * Active or chronic infectious hepatitis * Infectious process that, in the opinion of the Investigator, could compromise the subject's ability to mount an immune response * Clinically significant hepatic dysfunction, renal dysfunction and cardiac disease as defined in the protocol * Pregnant or breast-feeding women * Known drug abuse/alcohol abuse * Participation in another interventional clinical trial within the past 28 days (excluding purely observational studies) * Requires concurrent treatment with a non-permitted drug * Known hypersensitivity to any of the trial treatment ingredients * Legal incapacity or limited legal capacity * Any other reason that, in the opinion of the Investigator, precludes the subject from participating in the trial * Other protocol defined exclusion criteria could apply