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FDA approves CyPass micro-stent system for use with cataract surgery
The FDA has approved the CyPass micro-stent system for use in combination with cataract surgery to reduce IOP in adult patients with mild to moderate primary open angle glaucoma, according to a news release from the agency’s Center for Devices and Radiological Health.
The CyPass micro-stent system model 241-S (Alcon, a division of Novartis) includes the CyPass micro-stent, a loading device and a stent delivery tool. The micro-stent is placed in the angle of the eye with the distal end residing in the supraciliary space to allow outflow of fluid from the anterior chamber through the distal end into the supraciliary and suprachoroidal spaces.
The approval was based on a randomized clinical trial of CyPass, which included 505 patients with primary open angle glaucoma. Of these 505 patients, 374 patients received the CyPass micro-stent in combination with cataract surgery, and 131 patients underwent cataract surgery alone.
Researchers evaluated the percentage of patients with a 20% or more reduction in mean diurnal IOP from baseline and adverse events during a 24-month period.
At 24 months, 72.5% of patients who received the CyPass micro-stent and 58% of patients who underwent cataract surgery alone achieved significant reduction in IOP.
The most serious reported adverse events included hypotony, maculopathy, peripheral anterior choroidal effusion, IOL subluxation and corneal compromise, and safety concerns included bleeding, inflammation, and damage to angle tissue, the release said.
Other complications included device malposition and movement and tube obstruction.
Perspective
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The FDA approval of the CyPass suprachoroidal MIGS microstenting device is welcome news to those who treat glaucoma. It is particularly welcomed because CyPass has a novel mechanism as compared with other commonly employed surgical strategies. True, the suprachoroidal space has been utilized in the past, with very mixed results. Indeed, most glaucoma surgeons abandoned cyclodialysis surgery years ago. However, there is reason to believe that the CyPass is different from previous supraciliary procedures in that it produces more reproducible and more controlled outflow, and does so without any disruption of the conjunctiva and scleral tissues. Moreover, unlike canal stenting devices, the CyPass can be used in the open-angle glaucomas as well as in cases of complete synechial closure of the angle.
Exactly where the CyPass fits in remains to be seen. The FDA approval is for use combined with cataract surgery for mild to moderate glaucoma. Comparative data vs. other MIGS procedures such as canal-based outflow surgery are lacking. Surgeons will be interested in comparing both safety and efficacy outcomes with the various MIGS procedures. Will supraciliary stenting be safe enough to compete with canal-based procedures for early to moderate disease? Will early visual outcomes be comparable with canal-based and suprachoroidal procedures? How will efficacy compare? Better still, the hits should keep on coming with more surgical options anticipated in the not-too-distant future as we await submissions on subconjunctival outflow devices as well as new-generation canal stenting devices. Glaucoma and anterior segment surgeons are enjoying a newfound luxury of riches with more efficient and vastly safer procedures, even if less efficacious than traditional transscleral filtration surgery. Events of the last several years have forever changed the glaucoma surgical landscape, and in my opinion, there is no looking back.
Perspective
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Although a lot has been talked about regarding microinvasive glaucoma surgery (MIGS) in the U.S., the approval of CyPass (Alcon) by the FDA has now added onto what was a single player platform with the iStent (Glaukos). The primary study used for approval demonstrated at least a 20% reduction in IOP for 73% of patients with combined CyPass with cataract surgery vs. only 58% for those having cataract surgery alone. The CyPass micro-stent is intended to be used in mild to moderate glaucoma in conjunction with cataract surgery similarly to iStent, however with a different target site. The surgeon can decide whether to perform a procedure to bypass the proximal end of the diseased section of the trabecular meshwork with the use of the iStent to permit access to the Schlemm’s canal or attempt to direct aqueous to a different location through the CyPass to get into the suprachoroidal space. It is this difference in target sites that give surgeons variability when attempting to treat glaucoma patients. The clear drawback, however, is that both CyPass and iStent are indicated to be used with cataract surgery despite their different mechanism. In an ideal setting, surgeons would be able to capitalize on both methods to decrease IOP. This implies that both would need to be done at the same time, in that cataract surgery is only done once, and at the reduced 50% rate for the additional procedure.