The financing of drug trials by pharmaceutical companies and its consequences. Part 1: a qualitative, systematic review of the literature on possible influences on the findings, protocols, and quality of drug trials.
BACKGROUND
In recent years, a number of studies have shown that clinical drug trials financed by pharmaceutical companies yield favorable results for company products more often than independent trials do. Moreover, pharmaceutical companies have been found to influence drug trials in various ways. This paper provides an overview of the findings of current, systematic studies on this topic.


METHODS
Publications retrieved from a systematic Medline search on this topic from 1 November 2002 to 16 December 2009 were independently evaluated and selected by two of the authors. These publications were supplemented by further ones found in their references sections.


RESULTS
57 publications were included for evaluation in Parts 1 and 2 of this article. Published drug trials that were financed by pharmaceutical companies, or whose authors declared a financial conflict of interest, were found to yield favorable results for the drug manufacturer more frequently than independently financed trials whose authors had no such conflicts. The results were also interpreted favorably more often than in independently financed trials. Furthermore, there was evidence that pharmaceutical companies influenced study protocols in a way that was favorable to themselves. The methodological quality of trials financed by pharmaceutical companies was not found to be any worse than that of trials financed in other ways.


CONCLUSIONS
Published drug trials that are financed by pharmaceutical companies may present a distorted picture. This cannot be explained by any difference in methodological quality between such trials and trials financed in other ways.
Schott
Gisela
G
Arzneimittelkommission der deutschen Arzteschaft, Berlin, Germany. gisela.schott@akdae.de
Pachl
Henry
H
Limbach
Ulrich
U
Gundert-Remy
Ursula
U
Ludwig
Wolf-Dieter
WD
Lieb
Klaus
K
D002986:Clinical Trials as Topic / Q000191:economics* / Q000941:ethics*; D016265:Conflict of Interest / Q000191:economics*; D004345:Drug Industry / Q000191:economics* / Q000941:ethics*; D004994:Ethics, Pharmacy; D005858:Germany; D006801:Humans; D017594:Publication Bias; D012109:Research Support as Topic / Q000191:economics* / Q000941:ethics*
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