Preservative-free versus preserved latanoprost eye drops for reducing intraocular pressure: a non-inferiority phase III randomized, multi-center, single-blind, parallel-group controlled trial

Background: The aim of this study was to test the non-inferiority of preservative-free (PF) latanoprost 50 μg/mL multi-dose ophthalmic solution versus the marketed benzalkonium chloride (BAK)-preserved latanoprost 50 μg/mL ophthalmic solution in patients with open-angle glaucoma and patients with ocular hypertension. Methods: This was a prospective, national, randomized, multi-center, observer-blind, parallel-group controlled clinical trial. Patients were randomized to receive either PF or BAK-preserved latanoprost once daily for 12 weeks. The primary endpoint was the change in intraocular pressure (IOP) at 8:00 AM in the affected eye between the end of the treatment (week 12) and the baseline (week 0). Secondary measurements were taken at weeks 2 and 6, with IOP being recorded at 8:00 AM, 12:00 PM, and 4:00 PM. Results: A total of 158 patients were included in the per protocol (PP) population (77 in the PF latanoprost treatment arm and 81 patients in the BAK-preserved latanoprost treatment arm). PF latanoprost was non-inferior to BAK-preserved latanoprost in reducing IOP at 8:00 AM in the study eye from the baseline (week 0) to the end of the treatment (week 12). The point estimate of the between-treatment difference was 0.1 mmHg (95% confidence interval: -0.646, 0.847). Mean between-group differences in IOP reduction from the baseline to each of the secondary measurements were also similar between the two treatment arms. The two treatments were well tolerated and had comparable adverse event profiles. Conclusions: PF latanoprost was non-inferior to BAK-preserved latanoprost in reducing IOP in patients with open-angle glaucoma or ocular hypertension. Both treatments were well tolerated.