 - Receipt of concomitant or sequential chemoradiotherapy, consisting of a minimum of two cycles of platinum-based chemotherapy and a minimum radiation dose of 50 Gray Gy. Subjects must have completed the primary thoracic chemo-radiotherapy at least four weeks 28 days and no later than 12 weeks 84 days prior to randomization. Subjects who received prophylactic brain irradiation as part of primary chemo-radiotherapy are eligible 