Results of XEN45 Gel Stent Implantation in the Treatment of Primary Open-Angle Glaucoma Using 5, 10 or 20 μg Mitomycin C: A Pilot Study.

Background: No consensus has been reached on the adequate dose of mitomycin C (MMC) in XEN45 gel stent implantation. Lower doses have the potential to reduce MMC-linked side effects. This study aimed to evaluate treatment efficacy of ab interno XEN45 gel stent in primary open-angle glaucoma (POAG) with three different MMC doses. Methods: This retrospective single-centre nonrandomised trail included 54 patients (56 eyes) who underwent XEN45 gel stent implantation for POAG with above-target intraocular pressure (IOP) under medical therapy. Eyes were grouped according to the received MMC dose: Group 1 (20 μg; n = 21), Group 2 (10 μg; n = 14) and Group 3 (5 μg; n = 21). The primary endpoint was the mean IOP change in the three MMC dose groups after 6, 12 and 24 months. Secondary endpoints included the success rate defined as lowering of baseline IOP ≥ 20% and below a cut-off IOP set at three different levels: ≤ 18, ≤ 16 and ≤ 14 mmHg (Criteriums 1, 2 and 3), the mean number of ocular hypotensive medications and the frequency of needling procedures. Results: After 24 months, the overall mean (standard error) IOP was significantly reduced from 24.7 (0.9) mmHg to 15.2 (0.7) mmHg (p < 0.0001). The average IOP change (standard error) in MMC dose groups 1, 2 and 3 was -8.6 (2) mmHg, -10.1 (2.1) mmHg and -10.4 (2.8) mmHg. Complete success (Criterium 1) was achieved in 50%, 62% and 43% of the eyes in groups 1, 2 and 3. No statistically significant difference was found within the first 24 months between the three MMC dose groups for IOP change, success rate, number of ocular hypotensive medications and the frequency of needling procedures. Conclusions: XE45 was effective in all three dose groups. As the success rate did not significantly differ between the MMC doses, these results may support the use of the lowest dose. Trial Registration: ClinicalTrials.gov identifier: 559/2016BO2.