Efficacy of a preservative-free formulation of fixed-combination bimatoprost and timolol (Ganfort PF) in treatment-naïve patients vs previously treated patients
Authors Cordeiro MF, Goldberg I, Schiffman R, Bernstein P, Bejanian M
Received 7 March 2015
Accepted for publication 2 June 2015
Published 31 August 2015 Volume 2015:9 Pages 1605—1611
Checked for plagiarism Yes
Review by Single-blind
Peer reviewer comments 3
Editor who approved publication: Dr Scott Fraser
M Francesca Cordeiro,1 Ivan Goldberg,2 Rhett Schiffman,3 Paula Bernstein,3 Marina Bejanian3
1Western Eye Hospital, Imperial College Healthcare NHS Trust, London, UK; 2Discipline of Ophthalmology, University of Sydney, Sydney, NSW, Australia; 3Allergan, Inc., Irvine, CA, USA
Purpose: To evaluate, using subgroup analysis, the effect of treatment status on the intraocular pressure (IOP)-lowering efficacy of a preservative-free formulation of fixed-combination bimatoprost 0.03%/timolol 0.5% (FCBT PF).
Methods: A primary, multicenter, randomized, double-masked, 12-week study compared the efficacy and safety of FCBT PF with preserved FCBT (Ganfort®) in 561 patients diagnosed with glaucoma or ocular hypertension. For this analysis, eligible patients were treatment-naïve or had inadequate IOP lowering and underwent a washout of previous treatment. IOP (8 am, 10 am, and 4 pm) was measured at baseline and weeks 2, 6, and 12. Subgroup analysis of the FCBT PF arm assessed changes in average eye IOP from baseline in treatment-naïve vs previously treated patients. To evaluate the effect of treatment status at baseline (treatment-naïve vs previously treated) on IOP reduction in the FCBT PF treatment group, an analysis of covariance model was used with treatment status and investigator as fixed effects, and baseline average eye IOP, age, glaucoma diagnosis, and baseline average eye corneal thickness as covariates. P-values and the 95% confidence intervals were determined using the model.
Results: In the FCBT PF arm, IOP mean changes from baseline ranged from -8.7 mmHg to -9.8 mmHg in treatment-naïve patients (N=50), compared with -7.3 mmHg to -8.5 mmHg in previously treated patients (N=228). Baseline IOP, age, glaucoma diagnosis, and corneal thickness significantly affected IOP reduction in the FCBT PF group. Adjusting for these covariates, FCBT PF had a greater IOP-lowering effect (0.8–1.7 mmHg) in treatment-naïve patients than previously treated patients, which was statistically significant (P≤0.05) at seven of nine time points.
Conclusion: In this subgroup analysis, FCBT PF reduced IOP more effectively in treatment-naïve than in previously treated patients possibly due, in part, to altered responsiveness or tachyphylaxis that has been associated with prior ocular hypotensive agent treatment.
Keywords: glaucoma, ocular hypertension, intraocular pressure, bimatoprost, timolol, benzalkonium chloride
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