FDA Approves Hydrus Microstent for Microinvasive Glaucoma Surgery

The US Food and Drug Administration (FDA) has approved the Hydrus Microstent, a device used for microinvasive glaucoma surgery (MIGS) in patients with mild to moderate primary open-angle glaucoma, in conjunction with cataract surgery.

"We are pleased by the FDA's approval of our Hydrus Microstent," Dave Van Meter, President and CEO of Ivantis said in a statement. "Although the device has been used in over 4,000 procedures internationally, many of which are now well past five years, the Hydrus Microstent represents a novel device platform to FDA, and this approval occurred within our projected timeline.”

The Hydrus Microstent is approximately the size of an eyelash and is intended to reduce eye pressure by reestablishing flow through Schlemm’s canal in the eye. The device uses a three-pronged approach to restore the flow of fluid in the eye:

1. The microstent creates a bypass through the trabecular meshwork, allowing aqueous humor to flow out of the eye;
2. It dilates and supports Schlemm’s canal to increase outflow;
3. Finally the microstent spans 90 degrees of Schlemm’s canal to provide consistent access to the eye’s fluid collection channels.

"Ophthalmologists in the US will certainly welcome the approval of a next-generation canal-based MIGS device,” said David F. Chang, MD, clinical professor of ophthalmology at the University of California, San Francisco. “I look forward to offering Hydrus to my patients."

The FDA’s decision to approve was based in part on data from the HORIZON Trial that included 556 mild to moderate glaucoma patients undergoing cataract surgery. Study participants were randomized to either cataract surgery along with the Hydrus Microstent (treatment group) or cataract surgery alone (control group).

Of those in the Hydrus Microstent treatment group, 77.2% of patients achieved a ≥20% reduction in unmedicated intraocular pressure, a statistically significant decrease, at 24 months following the operation. In the control group, 57.8% achieved the same milestone, meeting the primary effectiveness endpoint.

“The Hydrus Microstent scaffolds approximately 90 degrees of the patient's natural canal outflow pathway. Correct anatomic placement into the canal will also be easier for surgeons to confirm,” said Chang.

A secondary effectiveness endpoint was also met, with patients in the treatment group achieving a mean intraocular pressure (IOP) reduction of 7.6 ± 4.1 mmHg (mean ± standard deviation), compared to a reduction of 5.3 ± 3.9 in the control group (difference = −2.3 mmHg; 95% CI, −3.0 to −1.6; P < 0.001).

“The overall body of clinical data supporting Hydrus is very encouraging in terms of both safety and two-year efficacy and sets a new bar for the treatment of mild to moderate glaucoma in cataract patients. It also appears to be very effective at eliminating medications, compared to cataract surgery alone,” added Chang.

Common adverse events reported include: partial or complete device obstruction (7.3%); worsening in visual field MD by > 2.5 dB compared with preoperative (4.3% vs. 5.3% for cataract surgery alone); device malposition (1.4%); and BCVA loss of ≥ 2 ETDRS lines ≥ 3 months (1.4% vs. 1.6% for cataract surgery alone).

“We are now proceeding with building our commercial and manufacturing infrastructures and intend to launch the product later this year,” said Van Meter. “We thank the FDA for their timely review, and we look forward to Hydrus Microstent becoming an important part of the cataract surgeons' and glaucoma specialists' surgical armamentarium."