title: Evaluation of investigator bias in industry-funded clinical trials of latanoprost.
abstract: OBJECTIVE
  To determine whether sponsorship of prostaglandin analogue (PGA) clinical trials results in investigator bias in outcomes when studying intraocular pressure (IOP).
  
  
  METHODS
  Retrospective, observational cohort study.
  
  
  METHODS
  A PubMed search was performed for latanoprost or Xalatan, bimatoprost or Lumigan, and travoprost or Travatan, with limits to humans, clinical trials, and English language. Inclusion criteria included randomized controlled trials, open-angle glaucoma, monotherapy with a PGA, baseline IOP ≥ 21 mm Hg, washout period, and minimum 1-month follow-up. Each article was reviewed by 2 independent reviewers. The results of IOP for each PGA were categorized as being sponsored by the parent company (the company manufacturing the PGA); by the competing company (the company manufacturing competing glaucoma therapy); or by a nonindustry source. The mean IOP and changes in IOP from baseline were compared among the 3 categories of sponsorship.
  
  
  RESULTS
  Only studies involving latanoprost were analyzed because of the low number of studies meeting the inclusion criteria for bimatoprost and travoprost. We found 29 and 13 studies that provided 1- and 3-month data, respectively, for analysis. The mean baseline IOPs in the 3 groups (parent company, competing company, nonindustry) were not significantly different (p = 0.47). The mean IOP at 1 (p = 0.72) and 3 months (p = 0.59) and the change in IOP from baseline (p = 0.83 and 0.90, respectively) were not significantly different in the 3 groups. A random-effects metaregression controlling for the covariates of blinding, naïveté to PGAs, and baseline IOP < 24 mm Hg or ≥ 24 mm Hg did not change the findings.
  
  
  CONCLUSIONS
  There was no evidence of investigator bias in determining outcomes for IOP in these clinical trials of latanoprost.
authors.affiliation: Department of Ophthalmology and Vision Sciences, University of Toronto, Toronto, Ontario.
authors.forename: Delan
authors.initials: D
authors.lastname: Jinapriya
authors.forename: Ayako
authors.initials: A
authors.lastname: Anraku
authors.forename: Tariq
authors.initials: T
authors.lastname: Alasbali
authors.forename: Graham E
authors.initials: GE
authors.lastname: Trope
authors.forename: Yvonne M
authors.initials: YM
authors.lastname: Buys
mesh_terms: D000577:Amides / Q000627:therapeutic use; D000959:Antihypertensive Agents / Q000627:therapeutic use*; D015982:Bias; D000069580:Bimatoprost; D002986:Clinical Trials as Topic; D003008:Cloprostenol / Q000031:analogs & derivatives / Q000627:therapeutic use; D015331:Cohort Studies; D004345:Drug Industry; D005902:Glaucoma, Open-Angle / Q000188:drug therapy; D006801:Humans; D007429:Intraocular Pressure / Q000187:drug effects; D000077338:Latanoprost; D011461:Prostaglandins F, Synthetic / Q000627:therapeutic use*; D012108:Research Personnel; D012109:Research Support as Topic; D012189:Retrospective Studies; D000069557:Travoprost; D016896:Treatment Outcome
chemical_list: D000577:Amides; D000959:Antihypertensive Agents; D011461:Prostaglandins F, Synthetic; D003008:Cloprostenol; D000077338:Latanoprost; D000069580:Bimatoprost; D000069557:Travoprost