A comparison between phase-III trials and a phase-IV study of nalmefene in alcohol use disorder patients. Is there a difference?

Abstract

Concerns regarding the external validity of phase-III trials are common to many medical disciplines, with relevant discrepancies found between experimental and clinical samples in some diseases such as hypertension. The aim of this study was to compare the samples included in the pivotal, phase-III clinical trials of nalmefene with that of a recently conducted phase-IV trial. Baseline characteristics of the studies were compared through univariate analysis. Significant differences were found in the percentage of low-risk drinkers included. Differences were also found in the prescription and intake pattern of nalmefene, as well as in the rate of psychiatric and addictive comorbidities, which were much higher in the phase-IV study. These data suggest that in the field of alcohol use disorders there are also relevant differences between experimental and clinical samples, a fact that reinforces the need for phase-III trials to be balanced with observational, phase-IV trials.