FDA approves trabecular micro-bypass stent

June 28, 2012
Ophthalmology Times Staff Reports

FDA approval has been granted for a trabecular micro-bypass stent (iStent, Models GTS100R/GTS100L; Glaukos), making the device the first ab interno glaucoma implant to be approved in the United States, according to the company.

Laguna Hills, CA-FDA approval has been granted for a trabecular micro-bypass stent (iStent, Models GTS100R/GTS100L; Glaukos), making the device the first ab interno glaucoma implant to be approved in the United States, according to the company.

The stent is indicated for use in conjunction with cataract surgery for the reduction of IOP in adult patients with mild-to-moderate, open-angle glaucoma currently treated with ocular hypotensive medication.

“We believe that [this new] micro-bypass offers a compelling new treatment option for glaucoma specialists and comprehensive ophthalmologists to advance glaucoma patient care,” said Thomas W. Burns, president/chief executive officer and director of Glaukos.

Made of non-ferromagnetic titanium, the 1-mm implant is the smallest medical device known to be implanted into the human body, said the company in a prepared statement. The stent works by creating a bypass through the trabecular meshwork to Schlemm’s canal to improve aqueous outflow through the natural, physiologic pathway.

An IDE pivotal study for the stent was the first prospective, randomized U.S. IDE trial for a glaucoma device. Conducted at 27 sites, the trial enrolled 239 subjects with mild-to-moderate open-angle glaucoma and clinically significant cataract. Subjects were randomly assigned 1:1 to either implant in conjunction with cataract surgery or cataract surgery alone.

Results showed that 68% of subjects in the implant treatment group (combined cataract and implantation) met the primary endpoint of IOP ≤21 mm Hg with no medications at 12 months, compared with only 50% of subjects in the cataract surgery-only group. This treatment difference of 18% in favor of the implant group on the primary endpoint at 12 months was statistically (p = 0.004) and clinically significant.

Similar results were obtained on the secondary endpoint of a ≥20% IOP reduction versus baseline at 12 months with 64% of the implant group achieving this endpoint compared with 47% in the cataract surgery-only group (p = 0.01).

The most common postoperative adverse events reported in the randomized pivotal trial included early postoperative corneal edema (8%), best-corrected visual acuity loss of ≥1 line at or after the 3-month visit (7%), posterior capsular opacification (6%), stent obstruction (4%), early postoperative anterior chamber cells (3%), and early postoperative corneal abrasion (3%).

Contraindications include eyes with primary or secondary angle-closure glaucoma, including neovascular glaucoma, as well as in patients with retrobulbar tumor, thyroid eye disease, Sturge-Weber syndrome, or any other type of condition that may cause elevated episcleral venous pressure.

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