Etrank: a ranking procedure for handling missing data in clinical trials: application to venlafaxine extended-release...

ETRANK is a statistical software which uses nonparametric (randomization) technique to analyze incomplete repeated measures data, where the pattern of withdrawal is treatment related. This stand alone program is written in C, presently runs in MS-DOS, and a Windows version is in development. The program has been developed based on methods developed by Entsuah (1990). These methods were presented at Statistics and Statistical Graphics Section of the 1991 SAS Users Group International Conference (SUGI-16). They were also presented to the Biometric Division of US Food and Drug Administration (FDA). ETRANK is now being used by CNS group of Wyeth-Ayerst Research as part of their NDA submission. This paper discusses ETRANK, and compares it with SAS PROC MIXED, and GEE. These methods are applied to Wyeth-Ayerst antidepressant Effexor-ER (extended release) data.