Simbrinza: new combination glaucoma treatment

on the 15 September 2014

Simbrinza (brinzolamide/brimonidine) is licensed for reducing intraocular pressure (IOP) in open-angle glaucoma or ocular hypertension when monotherapy is inadequate.

Simbrinza is the first combination eye drop available in the UK containing a carbonic anhydrase inhibitor and an alpha2 agonist.

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