Abstract
The design of a comparative treatment trial to evaluate the efficacy of therapeutics for progressive multifocal leukoencephalopathy (PML) is outlined. We propose a large simple randomized trial with patient survival as its primary endpoint, completed in a short period of time and involving a cohort with as few enrollment restrictions as possible. We use stratification as the counterweight to the lack of exclusion criteria and suggest that proper stratification will attenuate differences inherent in a heterogeneous subject cohort. Estimation of power, sample size, and study duration, implementation of interim analyses, toxicity management, and validation of secondary clinical measures are also addressed. Journal of NeuroVirology (2001) 7, 369-374.