Safety and Longevity of Intraocular Pressure Control After Bimatoprost Implant Administration: Interim Analysis of a Phase 3b Clinical Trial (TRITON).

Abstract

Background: Bimatoprost implant 10 µg is an intracameral, biodegradable implant that slowly releases bimatoprost to lower intraocular pressure (IOP). This study was designed to evaluate safety and the duration of the IOP-lowering effect after single and as-needed repeat administration of the bimatoprost implant in patients with open-angle glaucoma (OAG) and ocular hypertension (OHT).

Patients and methods: This study is an interim analysis of an ongoing, prospective, open-label, multicenter study in patients with OAG or OHT who are inadequately managed with topical IOP-lowering medication for reasons other than efficacy. IOP-lowering rescue treatment is allowed if implant retreatment criteria are not met. The primary endpoint is time to retreatment/rescue after the initial implant administration analyzed with the Kaplan-Meier method. Key safety measures include treatment-emergent adverse events (TEAEs) and reading-center evaluation of central corneal endothelial cell density (CECD). Analysis of data collected through 15 September 2023 focused on outcomes after a single or two implants.

Results: In total, 441 patients received the 10-µg bimatoprost implant in the study eye on day 1 (cycle 1), 179 patients received a second administration (cycle 2), and 378 patients had at least 12 months of follow-up data available. The median time (95% confidence interval) from the first administration to a second administration or rescue was 392 (369, 485) days; the probability of not requiring retreatment or rescue by day 360 was 57.5%. A second implant administration similarly provided a long duration of IOP control. The baseline mean (standard error, SE) IOP was 25.6 (0.14) mmHg; the mean (SE) change from baseline IOP in unrescued eyes after a single administration was - 7.5 (0.21) mmHg at week 24 and - 6.4 (0.28) mmHg at month 12. Conjunctival hyperemia, typically associated with the administration procedure, was the most common ocular TEAE (cycle 1, 14.3%; cycle 2, 12.8%). Mean (SE) percentage change in CECD from baseline at 12 months after administration was - 4.3 (0.81)% in cycle 1 and - 8.5 (2.22)% in cycle 2. The cycle 1 implant was no longer visible or ≤ 25% of initial size in 66.3% and 94.3% of study eyes at months 12 and 24, respectively.

Conclusions: In this interim analysis based on available data, the IOP-lowering effect of the initial administration of the 10-µg bimatoprost implant was well maintained for > 1 year in most patients. Results after a second administration were comparable. The safety profile of initial and repeat administration was acceptable.

Trial registry: ClinicalTrials.gov identifier NCT03850782; registered 20 February 2019.