title: Industry sponsorship and selection of comparators in randomized clinical trials.
abstract: BACKGROUND
  Most clinical trials on medical interventions are sponsored by the industry. The choice of comparators shapes the accumulated evidence. We aimed to assess how often major companies sponsor trials that involve only their own products.
  
  
  METHODS
  Studies were identified by searching ClinicalTrials.gov for trials registered in 2006. We focused on randomized trials involving the 15 companies that had sponsored the largest number of registered trials in ClinicalTrials.gov in that period.
  
  
  RESULTS
  Overall, 577 randomized trials were eligible for analysis and 82% had a single industry sponsor [89% (166/187) of the placebo-control trials, 87% (91/105) of trials comparing different doses or ways of administration of the same intervention, and 78% (221/285) of other active control trials]. The compared intervention(s) belonged to a single company in 67% of the trials (89%, 81% and 47% in the three categories respectively). All 15 companies strongly preferred to run trials where they were the only industry sponsor or even the only owner of the assessed interventions. Co-sponsorship typically reflected co-ownership of the same intervention by both companies. Head-to-head comparison of different active interventions developed by different companies occurred in only 18 trials with two or more industry sponsors.
  
  
  CONCLUSIONS
  Each company generates a clinical research agenda that is strongly focused on its own products, while comparisons involving different interventions from different companies are uncommon. This diminishes the ability to understand the relative merits of different interventions for the same condition.
authors.affiliation: General Hospital George Papanikolaou, Thessaloniki, Greece.
authors.forename: D N
authors.initials: DN
authors.lastname: Lathyris
authors.forename: N A
authors.initials: NA
authors.lastname: Patsopoulos
authors.forename: G
authors.initials: G
authors.lastname: Salanti
authors.forename: J P A
authors.initials: JP
authors.lastname: Ioannidis
mesh_terms: D016265:Conflict of Interest; D004345:Drug Industry / Q000191:economics*; D016032:Randomized Controlled Trials as Topic / Q000191:economics*; D012109:Research Support as Topic