A quality of life (QOL) endpoint supplemented standard clinical endpoints of survival, tumor response, and toxicity in a double-blind study conducted by the Cancer and Leukemia Group B (CALGB) where 291 patients with advanced non-small cell lung cancer (NSCLC) were randomly assigned to receive cisplatin/vinblastine with either hydrazine sulfate (HS) or placebo. The difficulties associated with the analysis of the longitudinal QOL data, and the contributions that the QOL endpoint made to the understanding of treatment differences, will be the focus of this paper.