Glaukos has received Therapeutic Goods Administration (TGA) approval in Australia for its iStent infinite Trabecular Micro-Bypass System, offering an improved option for glaucoma surgeons and patients.
The key difference between iStent infinite and previous generation iStent systems is the inclusion of three heparin-coated titanium stents – as opposed to two – preloaded into a newly designed auto-injection system offering unlimited delivery attempts.
According to the company, this allows the surgeon to inject stents across a span of up to approximately six clock hours around Schlemm’s canal, the eye’s primary drainage channel.
The iStent infinite falls within the minimally invasive glaucoma surgery (MIGS) category that surgeons typically use as an intermediate therapy where other options have failed for glaucoma patients. It is intended to reduce intraocular pressure (IOP) in adult patients diagnosed with primary open-angle glaucoma (POAG) currently treated with ocular hypotensive medication.
Once in place, the stents are designed to lower IOP by restoring the natural, physiological outflow of aqueous humor. The iStent infinite has a similar mechanism of action to the company’s two-stent iStent inject W Trabecular Micro-Bypass System.
Glaukos said its new “elegant, precision-engineered injector system” had some unique features. Most notably, the company has incorporated a stent delivery button designed for smooth stent deployment with an unlimited number of delivery attempts. This is a significant advance over previous iStent injectors which offered four delivery attempts.
To improve intraoperative visibility for the surgeon, the company has developed an eight-degree angled insertion tube designed to minimise incision interference and provide greater access to deliver stents widely. There are also ‘viewing windows’ to visualise stent positioning in the insertion tube.
In Australia, the device has secured reimbursement when implanted with or without cataract surgery, and is also covered by private health insurance.
To demonstrate the device’s efficacy and safety, in a prospective, multicentre, 12-month pivotal trial, patients with open-angle glaucoma who had failed prior surgical intervention underwent standalone iStent infinite implantation.1 Notably, those enrolled had a significantly higher preoperative treatment burden with more severe glaucoma as compared to other trabecular bypass MIGS pivotal trials.1,2, 3
Despite this tough-to-treat population, Glaukos said the iStent infinite “delivered exceptional results” demonstrating sustained efficacy throughout the course of the study.1
The study found 73.5% of patients had ≥20% reduction in IOP, and 47.3% had a ≥30% reduction. And 91.7% of study participants in the failed prior surgery group reduced or maintained medication burden at 12 months.1 There was also a 16.9 mmHg mean diurnal IOP in patients who did not have an IOP-related secondary surgical intervention (SSI, n=57), corresponding to a mean reduction of 6.5 mmHg (27.7%).4
Safety wise, Glaukos said in the trial, iStent infinite showed “exceptional intraoperative and postoperative safety” among patients with two or more failed filtering surgeries.1
This new approach occupies 3% of the Schlemm’s canal, leaving 97% untouched.
In the study, there were zero cases of hypotony, explants, cyclodialysis clefts created, and device-related interventions.
In 4% of eyes (n=3), these required SSI following iStent infinite implantation through5 months, despite multiple failed prior surgical interventions,4 the company said.
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References
- Glaukos Data on File.
- Summary of safety and effectiveness data. Alcon Laboratories, Inc; 2016.
- Samuelson TW, Chang DF, Marquis R, et al. A Schlemm canal microstent for intraocular pressure reduction in primary open-angle glaucoma and cataract. Ophthalmology. 2019;126(1):29-37.
- iStent infinite. Instructions for use. Glaukos Corporation; 2022.
- Johnstone MA. The aqueous outflow system as a mechanical pump: evidence from examination of tissue and aqueous movement in human and non-human primates. J Glaucoma. 2004;13(5):421-438.
