Australia’s Therapeutic Goods Administration (TGA) has approved the iStent infinite trabecular micro-bypass system, manufactured by Glaukos, for use in Australia.
This innovative device is designed to reduce intraocular pressure (IOP) in adult patients diagnosed with primary open-angle glaucoma (POAG) who are currently treated with ocular hypotensive medication.
For Dr Colin Clement, the first ophthalmologist to implant the iStent infinite in Australia, the new technology has quickly become his “go to angle-based MIGS (minimally invasive glaucoma surgery) device for glaucoma management”.
The iStent infinite offers a potential alternative to continuous medication use for many patients. Notably, it can be implanted either as a standalone procedure or in conjunction with cataract surgery, providing flexibility in treatment options. This broadens the scope of MIGS treatments available to Australian ophthalmologists and their patients, including those who have previously undergone cataract surgery and subsequently developed glaucoma, and those who have failed prior medical and surgical interventions. It can also be considered for patients uncontrolled on medication, those non-compliant or non-adherent to treatment, and individuals allergic or intolerant to glaucoma medications.
For eligible patients, the iStent infinite is covered by private health insurance.
The iStent infinite system comprises three heparin-coated titanium stents preloaded into an auto-injection system. This design allows surgeons to inject the stents across a span of up to approximately six clock hours around Schlemm’s canal, the eye’s primary drainage channel.
Once implanted, the stents are engineered to lower IOP by restoring the natural, physiological outflow of aqueous humor. This mechanism of action is similar to Glaukos’ two stent iStent inject W Trabecular Micro-Bypass System, building upon proven technology.
STRONG CLINICAL DATA
Clinical data from the iStent infinite pivotal trial demonstrated impressive results. 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, these patients had a significantly higher preoperative treatment burden with more severe glaucoma as compared to other trabecular bypass MIGS pivotal trials.1,2,3
On average, they’d had two failed prior surgeries including trabeculectomy, a 3.0 medication burden and had a mean IOP of 23.5 mmHg.1
Among these patients, a mean diurnal IOP of 17.0 mmHg was achieved at 12 months, corresponding to a mean reduction of 6.5 mmHg (27.7%) from baseline.4 Furthermore, 73.4% of patients achieved at least a 20% reduction in mean diurnal IOP from baseline at 12 months, while maintaining the same or fewer medications. Even more striking, 47.3% of patients achieved a 30% or greater reduction.4
The pivotal trial also highlighted the device’s safety in a challenging patient population. Only 4.9% of eyes required secondary surgical intervention following iStent infinite implantation through 12 months, despite multiple failed prior surgical interventions in the study cohort.4
Glaukos hopes the newly approved iStent infinite will help surgeons overcome patient non-compliance with glaucoma medications, something that remains a significant challenge in managing glaucoma. Studies have shown that approximately 50% of patients stop taking their prescribed glaucoma medications within six months, and over 90% do not refill their topical medications continuously over a three-year period, often citing side effects as their reason.5 Even in glaucoma patients who are ‘controlled’ there is a prominent risk of disease progression.
IMPROVEMENTS OBVIOUS
Having used the iStent infinite twice at the time of going to print, Dr Clement explained that “the iStent infinite represents an evolution and further improvement to the iStent glaucoma system”.
“Changes have been made to the injector, which allows surgeons to implant stents with improved visibility and repeatability. It’s also the first time the iStent system has become available with three pre-loaded stents, meaning an increased likelihood of achieving the desired IOP reduction or medication reduction.”
Dr Clement said the improvements were immediately obvious. “The injector mechanism is easier to use with excellent ergonomics under microsurgical conditions and I found the stent placement to be more predictable. Now that iStent infinite is available in Australia, it is my go-to angle-based MIGS device for glaucoma management, both in combination with cataract surgery and as a stand-alone treatment.”
He said the iStent infinite “should be considered in any patient with glaucoma that requires cataract surgery where reduced medication burden and/ or reduced IOP is likely to be beneficial. It may also be of benefit in patients where glaucoma is not adequately controlled, and more aggressive surgery is not appropriate or has already failed.”
References
- Glaukos Data on File
- CyPass. 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.
- Nordstrom BL, Friedman DS, Walker AM et al. Persistence and adherence with topical glaucoma therapy. Am J Ophthalmol. 2005;140(4):598-606.
