Abstract
Purpose: :
To determine if sponsorship of prostaglandin analogue (PGA) clinical trials (by parent company, competing company, non-industry source, unknown source) has an impact on intraocular pressure (IOP) outcomes.
Methods: :
A PubMed search was performed on August 8, 2008 for "Latanoprost OR Xalatan", "Bimatoprost OR Lumigan", "Travoprost OR Travatan", with limits to humans, clinical trials and English. 473 articles were retrieved and reviewed for the following inclusion criteria: randomized controlled trial (RCT), open angle glaucoma, monotherapy with PGA, baseline IOP > 21mmHg, washout period, minimum 1 month follow-up. IOP measurements at baseline, 1 month and 3 months were extracted from the articles. Each article was reviewed by 2 reviewers. Discrepancies between reviewers were resolved by the article being reviewed by a third reviewer. The PGA IOP results were categorized as being sponsored by the Parent company, Competing Company, Non-industry or by an Unknown source. The mean IOPs for each group were compared and analyzed for statistically significant differences. Statistical analyses were performed with SASS.
Results: :
58 articles met the inclusion criteria. Latanoprost, Bimatoprost and Travoprost were investigated in 41, 7 and 5 studies respectively. Only Latanoprost studies were analyzed because of the low number of studies that met inclusion criteria for Bimatoprost and Travoprost. 30 of the 41 studies investigating Latanoprost provided 1 month data and were used for analysis. 11 of these studies were sponsored by the parent company (Pfizer/Pharmacia), 3 by a competing company (Allergan, Alcon), 11 by non-industry sources, and 5 with unknown sponsorship. The mean baseline IOP between these 4 groups was not significantly different (p=0.82). The mean IOP achieved at 1 month was not significantly different between the 4 groups (p=0.53).
Conclusions: :
For RCTs evaluating Latanoprost, the nature of who sponsored the study did not impact IOP outcomes at 1 month. There is no evidence of short-term bias based on study sponsorship for RCTs that evaluated Latanoprost.
Keywords: intraocular pressure • clinical (human) or epidemiologic studies: biostatistics/epidemiology methodology • outflow: ciliary muscle