Abstract
Purpose:
Currently, there are no head-to-head studies comparing brimondine-timolol fixed combination (BTFC) to brinzolamide-brimondine fixed combination (BBFC). Since comparative data is useful for clinical and reimbursement decision making, we compared the safety and efficacy of these two agents using an indirect treatment comparison (ITC) analysis.
Methods:
A systematic literature review was performed to identify relevant literature which contained safety and efficacy data on BBFC or BTFC. Safety outcomes included discontinuation due to adverse events (AEs), dry mouth, allergic conjunctivitis, and eye pruritis. Efficacy was defined as intraocular pressure (IOP) change from baseline. BBFC and BTFC studies were included when they presented the appropriate safety or efficacy data, and included a common comparator (brimonidine) to link between the treatments of interest. Direct meta-analyses were performed where more than one study for a given comparison was included. The indirect treatment comparison was then performed using Bucher’s method.
Results:
Two studies of BBFC vs. brimonidine and 1 study of BTFC vs. brimonidine were identified to be included in the analysis. Compared to BBFC, BTFC demonstrated a 79% reduced probability of discontinuing treatment due to any AEs (RR [95% CI]: 0.21 [0.10, 0.42]). BTFC also reduced the probability of dry mouth by 84% (RR [95% CI]: 0.16 [0.05, 0.48]), allergic conjunctivitis by 80% (RR [95% CI]: 0.20 [0.04, 0.88]) and eye pruritis by 84% (RR [95% CI]: 0.16 [0.01, 3.08]), however these results are limited by the small number of events reported. IOP change from<br /> baseline at week 12 was similar between BTFC and BBFC (mean differences during the day ranged from -1.19 to 1.47) with BTFC demonstrating a larger peak effect in the morning and BBFC demonstrating a larger trough effect in the afternoon, possibly due to the 3 times a day dosing for BBFC compared to the twice-a-day dosing for BTFC.
Conclusions:
Indirect comparisons are a useful tool in the absence of head to head data. Results may be limited when there is significant heterogeneity among studies; however in this analysis 2 out of the 3 studies included were identical in study design. In this analysis, BTFC demonstrated a superior tolerability profile and comparable efficacy vs. BBFC.