Statistical considerations for stopping systemic lupus erythematosus clinical trials earlier

Group sequential designs are used to potentially shorten randomized clinical trials and thereby reduce subject burden, improve safety, and save time and resources. Clinical trials comparing treatments for systemic lupus erythematosus (SLE) might adopt such designs if the ordinal outcome scales for SLE, such as the Systemic Lupus Activity Measure and Systemic Lupus Erythematosus Disease Activity Index, were more like continuous outcome scales with interval properties. After describing the basic features of sequential trials and highlighting some major issues in their design, we propose approaches that mitigate these issues. In particular, high-speed computing has accelerated advances in sequential design, making available a variety of designs that can be implemented with minimal technical support. The challenge now is to understand the concepts behind such flexible designs and then to apply them to improve studies of SLE.