he objective of the project is to develop sequential statistical methods for the data monitoring of complex clinical trials in cancer. In many of these clinical trials, the principal outcomes include immediate responses that can be completely measured soon after a patient enters the study; or in many others, time to an event; responses recorded periodically over time, or events that recur over time. Sequential monitoring of responses of these types in large clinical trials usually fit into a unified framework. NCI Grant 5-RO1-CA55098, 1991-1995.