PHARMACOLOGY
The carbonic anhydrase inhibitor brinzolamide reduces ocular pressure by decreasing the production of aqueous humour. Brimonidine is an alpha2 adrenergic agonist that targets receptors in the ciliary epithelium, also suppressing aqueous humour formation.1
CLINICAL STUDIES
The safety and efficacy of a fixed-dose combination of brinzolamide 1% and brimonidine tartrate 0.2% was compared with that of brinzolamide or brimonidine monotherapy in 560 patients with open-angle glaucoma and/or ocular hypertension who had insufficient IOP reduction with their existing regimens or were receiving multiple IOP-lowering medications. All drugs were administered twice daily.2
In terms of mean change in diurnal IOP at month 3 (the primary endpoint), the combination was statistically superior to both brinzolamide (least squares mean difference: -1.4mmHg; p<0.0001) and brimonidine (least squares mean difference: -1.5mmHg; p<0.0001) as monotherapy.2
Mean percentage reductions in IOP from baseline were 26.7% to 36% with the combination, 22.4% to 27.9% with brinzolamide alone and 20.6% to 31.3% with brimonidine alone.2
A second study involving 890 patients compared the fixed-dose combination with brinzolamide and brimonidine administered individually. Mean change in diurnal IOP from baseline to month 3 with the combination drops was non-inferior to that observed with the two drugs administered separately.1
The mean reduction in IOP with the combination drops at month 3 was 8.5mmHg compared with 8.3mmHg with the separate drops.1
Safety profile
The safety profile of the combination was consistent with that of the individual components.2 The most commonly reported adverse reactions in patients treated with Simbrinza were ocular, and included hyperaemia, blurred vision, allergic-type reactions and discomfort.1
References
- Simbrinza Summary of Product Characteristics, July 2014.
- Aung T et al. Ophthalmology 2014, accepted article; doi: 10.1016/j.ophtha.2014.06.022
Further information: Alcon Laboratories