Pemetrexed in Advanced Non-Small-Cell Lung Cancer: at Progression vs Maintenance Therapy After Induction Chemotherapy

In previous studies without maintenance therapy, median overall survival (OS) for performance status (PS) 0-1 patients has been approximately 9 months, corresponding to 6 months from randomization in this study. We consider an improvement in overall survival of two months to be the minimum difference that will lead to routine use of maintenance pemetrexed in Norway. To demonstrate an improvement in median overall survival from 6 to 8 months with an α =0.05 and β =0.20, 198 evaluable patients are required on each arm. We expect a drop-out rate of maximum 10 %, and therefore intend to randomize a total of 436 patients (PS 0-1) - of which we expect 150 to be 70 years or older. Sample size is calculated on PS 0-1 patients only. In addition, PS 2 patients will be randomized until the required number of PS 0-1 patients have been accrued. We estimate that a total of 100 PS 2 patients will be enrolled - sufficient for hypothesis-generating analyses of the benefit of maintenance therapy in elderly and PS 2 patients. Based on experience from our previous studies we estimate that approximately 30% of patients will not complete or progress during induction chemotherapy; or be ineligible due deterioration of PS. Consequently, we need to include approximately 765 patients.