PURPOSE: To analyze the extent and prevalence of the placebo effect in prior early-phase glaucoma clinical studies. METHODS: Articles were evaluated on phase I and II trials of glaucoma medicines that became commercially available after 1977 with a placebo arm that involved glaucoma patients. RESULTS: We included 23 studies with 23 treatment arms with a total of 1703 patients in articles evaluating 10 different glaucoma medications. This study showed that at 8 AM (n = 18), the average decrease in placebo from untreated baseline was 2.3 ± 1.6 mm Hg (9%), while for the diurnal curve (n = 17), the mean decrease was 1.4 ± 1.1 mm Hg (6%). At 8 AM, 8/18 treatment arms had greater than 2 mm Hg intraocular pressure (IOP) decrease, and all had at least some reduction in IOP. For the diurnal curve, 4 of 17 studies had reduced IOP greater than 2 mm Hg. One treatment arm had no placebo effect. CONCLUSIONS: This study suggests that a placebo effect is common in glaucoma clinical trials and potentially could limit the ability to evaluate the efficacy of a new medicine.
PURPOSE: To analyze the extent and prevalence of the placebo effect in prior early-phase glaucoma clinical studies. METHODS: Articles were evaluated on phase I and II trials of glaucoma medicines that became commercially available after 1977 with a placebo arm that involved glaucomapatients. RESULTS: We included 23 studies with 23 treatment arms with a total of 1703 patients in articles evaluating 10 different glaucoma medications. This study showed that at 8 AM (n = 18), the average decrease in placebo from untreated baseline was 2.3 ± 1.6 mm Hg (9%), while for the diurnal curve (n = 17), the mean decrease was 1.4 ± 1.1 mm Hg (6%). At 8 AM, 8/18 treatment arms had greater than 2 mm Hg intraocular pressure (IOP) decrease, and all had at least some reduction in IOP. For the diurnal curve, 4 of 17 studies had reduced IOP greater than 2 mm Hg. One treatment arm had no placebo effect. CONCLUSIONS: This study suggests that a placebo effect is common in glaucoma clinical trials and potentially could limit the ability to evaluate the efficacy of a new medicine.
Authors: Jay S Pepose; Paul J Hartman; Harvey B DuBiner; Marc A Abrams; Robert J Smyth-Medina; Sayoko E Moroi; Alan R Meyer; Mina P Sooch; Reda M Jaber; Konstantinos Charizanis; Seth A Klapman; Arin T Amin; Jonah E Yousif; Eliot S Lazar; Paul M Karpecki; Charles B Slonim; Marguerite B McDonald Journal: Clin Ophthalmol Date: 2021-01-08