Implantation of a minimally-invasive glaucoma surgery (MIGS) drainage device can significantly reduce intraocular pressure (IOP), even when delivered in a standalone procedure, in eyes with primary open-angle glaucoma (POAG) uncontrolled by prior therapy, according to research published in the Journal of Glaucoma. The technique has a favorable safety profile as well, according to the study.
Researchers conducted a prospective, multicenter, single-arm, open-label clinical trial to evaluate the safety and efficacy of the iStent Infinite® (3 iStent inject W stents, Glaukos) in patients with POAG unable to be controlled by prior surgical or medical therapy or maximally-tolerated medical therapy (MTMT) . The investigators implanted the MIGS device as a standalone surgical procedure. (ClinicalTrials.gov Identifier: NCT03639870).
The efficacy endpoints were the proportion of eyes achieving ≥20% mean diurnal intraocular pressure (MDIOP) reduction from baseline at month 12 on the same or fewer IOP-lowering medication classes (responder endpoint) and mean change in MDIOP from baseline at month 12. Safety measures included visual acuity, slit-lamp and fundus examinations, gonioscopy, perimetry, surgical complications, and adverse events (AEs).
A total of 72 eyes of 72 patients (median age, 72.0 years; range, 49-89; 48.6% men and 51.4% women) were included in the study. The patients had a preoperative mean medicated MDIOP of 23.4±2.8 mm Hg and were taking a mean of 3.1±0.9 IOP-lowering medications. Most eyes (61/72; 84.7%) had failed prior surgery (failed-surgery subgroup), while the remaining eyes (11/72; 15.3%) had open-angle glaucoma uncontrolled on MTMT (MTMT subgroup).
The investigators demonstrated that 76.1% of all patients met the responder endpoint, 73.4% of the failed-surgery subgroup and 90.9% of the MTMT subgroup. They observed a mean reduction in MDIOP at month 12 for both groups of 5.9±0.6 mm Hg (5.5±0.7 mm Hg in the failed-surgery subgroup, and 8.1±0.9 mm Hg in the MTMT subgroup).
For patients taking the same amount of or fewer medications as baseline, the team demonstrated that 53.0% achieved a 30% of higher reduction in MDIOP without surgical interventions/other events.
The patients demonstrated that the device has a favorable safety profile, with no explants, infection, device-related interventions or hypotony, or serious ocular AEs. They found that 52.8% of patients did not experience any postoperative AEs in the study eye and 93% maintained their preoperative best-spectacle corrected visual acuity or had a decrease of less than 2 lines at month 12.
“The iStent infinite also has a favorable microscopic size-vs-outflow ratio, with 3 stents occupying ~3% of the trabecular meshwork angle but designed to enable up to 240 degrees of aqueous outflow with minimal tissue disruption,” according to the researchers. “Despite this micro-scale tissue footprint, each stent can sustain outflow equal to the entire rate of aqueous humor production by the human body. Furthermore, the incremental benefits of additional stents (e.g. 3 vs 2 vs 1 stent), such as additional IOP reduction and reduced medication burden, have been validated in both preclinical and clinical studies, with favorable safety in all treatment groups.”
Limitations of the study included the relatively short follow-up duration and lack of a medication washout period due to concern of placing patients at undue risk of optic nerve damage.
Disclosure: This study was supported by the Glaukos Corporation. Multiple study authors declared affiliations with biotech, pharmaceutical, and/or device companies. Please see the original reference for a full list of authors’ disclosures.
Sarkisian SR Jr, Grover DS, Gallardo M, et al. Effectiveness and safety of iStent infinite trabecular micro-bypass For uncontrolled glaucoma. J Glaucoma. Published online October 20, 2022. doi:10.1097/IJG.0000000000002141