Glaukos announced that the US Food and Drug Administration (FDA) is allowing the company to move forward with a US investigational device exemption (IDE) pivotal study of its iStent SA trabecular micro-bypass system.

The iStent SA is intended for use as a standalone procedure for the reduction of intraocular pressure (IOP) in pseudophakic, mild-to-moderate primary open-angle, pigmentary or pseudoexfoliative glaucoma patients.

Pseudophakic refers to patients who have previously undergone cataract surgery and no longer have a natural crystalline lens. The iStent SA consists of two micro-scale titanium stents that are preloaded in an auto-injection system, which allows a surgeon to inject stents into multiple trabecular meshwork locations through a single corneal entry point.

Once placed, the stents are designed to restore physiological outflow of aqueous humor through the trabecular meshwork and into Schlemm’s canal, the eye’s primary drainage system.

The multi-center, pivotal phase randomized trial will enroll approximately 400 subjects and evaluate iStent SA compared to selective laser trabeculoplasty (SLT), a procedure where short laser pulses are used to target specific trabecular meshwork cells in order to increase aqueous humor outflow.

Approximately 80 additional subjects from the initial trial phase will also be included in the pivotal trial. The primary efficacy endpoint is non-inferiority to SLT at one year postoperative.

“We are delighted that our successful collaboration with the FDA allows Glaukos to begin the pivotal phase of this first-ever standalone Micro-Invasive Glaucoma Surgery, or MIGS, trial,” said Thomas Burns, president and chief executive officer.

“We pioneered MIGS to overcome the challenges of conventional glaucoma therapies. Our commencement of the iStent SA trial brings us a step closer to making an approved MIGS option available to address an unmet clinical need and to treat a wider cohort of glaucoma patients.”

The iStent SA relies on the same fluidic method of action as the company’s first-generation iStent® Trabecular Micro-Bypass Stent, which has been shown to lower IOP in adult cataract patients with mild-to-moderate open-angle glaucoma.

Each iStent SA stent is approximately 0.4 mm x 0.4 mm, or about one-third the size of iStent, which the company believes is the smallest medical device ever approved by the FDA.

Glaucoma is characterized by progressive, irreversible and largely asymptomatic vision loss caused by optic nerve damage. There is no cure for the disease and reducing IOP is the only proven treatment.

Based on analysis of population-based surveys, medical claims data and other statistics, the company estimates that there are approximately 5.4 million people in the U.S. with primary open-angle glaucoma, the most common form of the disease. Glaukos estimates that approximately one-third of this U.S. primary open-angle glaucoma population is pseudophakic.