Long-term safety and patient-reported outcomes of iStent inject trabecular micro-bypass stent system
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First Author: B.Williamson USA
There is continued interest in long-term corneal endothelial safety with MIGS technology; there is also a need for more patient-reported outcomes (PRO) data with MIGS. In this analysis, endothelial cell density (ECD) and endothelial cell loss (ECL) >30% from baseline were examined to 3 years in a subset of subjects in the iStent inject pivotal randomized controlled trial. Patient-reported outcomes data are sparse in clinical decision making for patients with primary open-angle glaucoma (POAG).
A total of 41 U.S. clinical sites enrolled and randomized subjects for this study.
ECD and ECL >30% from baseline were compared in two study groups over 3 years: iStent inject + phaco (INJ; n=135) and phaco alone (CS; n=40). Post-hoc analysis was conducted of PRO data [Visual Function Questionnaire (VFQ-25) and Ocular Surface Disease Index (OSDI)] collected at five time intervals (baseline, 1, 6, 12, 24 months). Minimal important difference (MID) was calculated for composite scores using distributional approach whereby MID was defined as half SD of baseline scores. Responders were defined as patients with change from baseline ≥ MID. Responders were compared by aggregate level and baseline IOP (<25 and ≥25 mmHg).
At 3-years follow-up, mean central ECD % change from Screening was similar between INJ and CS (-12% vs -14%, respectively). ECL >30% was also similar (6.7% in INJ eyes vs 10.0% in CS eyes). A greater percentage of PRO responders was observed over 2-years in INJ vs CS eyes (58.0% vs. 45.8% for VFQ and 56.7% vs. 48.9% for OSDI; p-value < 0.05). Differences in responder rates ranged from 9.3% to 14.1% and 6.3% to 7.8%, respectively, over 2-years. Improvements were greater in higher baseline IOP (≥25 mmHg) with responder rates ranging from 10.1% to 21.8% and 11.4% to 16.8%.
Three-year outcomes demonstrate similar long-term corneal endothelial safety with iStent inject + phaco vs phaco alone. These outcomes add to the well-established long-term safety of iStent inject. Post-hoc exploratory analysis of VFQ-25 and OSDI data suggest iStent inject + phaco may improve overall ocular symptoms and visual functioning vs cataract surgery alone with durability over 2 years. iStent inject is a promising treatment option for patients with glaucoma.