INTRODUCTION: The purpose of this study was to evaluate intraocular pressure (IOP) lowering and safety of XEN((R)) stent in medically refractory, progressive, open-angle glaucoma (OAG). METHODS: Forty-seven eyes of 42 patients were treated with XEN((R)) stent alone or combined with phacoemulsification. RESULTS: Mean IOP decreased from 22.34 +/- 7.34 mmHg to 12.91 +/- 4.21, 12.95 +/- 4.36, 13.49 +/- 3.91, and 13.36 +/- 3.63 mmHg at 1, 3, 6, and 12 months (95% confidence interval [CI] [20.24, 24.44], [11.71, 14.12], [11.63, 14.27], [12.36, 14.62], and [12.10, 14.62]), respectively. Mean number of medications decreased from 2.96 +/- 1.20 (95% CI [2.62, 3.30]) at baseline to 0.75 +/- 1.27 (95% CI [0.31, 1.19]) at 1 year. At 1 year (n = 32), complete success was achieved in 68.8% (n = 22/32) (i.e., IOP reduction >/= 20% and IOP < 18 mmHg without medication or any secondary glaucoma intervention). Qualified success was achieved in 90.6% (n = 29/32) (i.e., IOP reduction of >/= 20% and IOP < 18 mmHg with and without medication or any secondary glaucoma intervention). Eleven eyes had not yet reached 12 months. Two patients (three eyes) died before 1 year; one patient (one eye) was lost to follow up. Adverse events: localized choroidal hemorrhage in one eye; hypotony (IOP < 6 mmHg) at day 1 in 10 eyes, with full resolution by 2 weeks. No persistent hypotony or maculopathy occurred. Stent erosion with removal occurred in two eyes. Fourteen eyes (29.8%) underwent needling. One patient required trabeculectomy. CONCLUSIONS: XEN((R)) stent is effective and relatively safe surgery for medically refractory, progressive, OAG out to 1 year. Intraocular pressure and medications were significantly reduced.