The principal investigator of the Hydrus II study this week presented one-year results for the Hydrus Microstent, showing that the micro invasive glaucoma surgery (MIGS) device was superior to cataract surgery alone.
Professor Norbert Pfeiffer presented the results of the randomized, controlled multicenter study at the World Glaucoma Congress.
"This is the first randomized, controlled, multicenter study to demonstrate superiority of a MIGS device versus cataract surgery alone without the confounding presence of topical medications," Dr. Pfeiffer said. "The Hydrus group performed very well, lowering pressure by 20% or more in 92% of patients without any medication. Importantly, there were no differences in safety between groups. We observed a remarkably consistent effect across the study and in our own experience as an investigational center. Interestingly, the control group performed better than expected, which reaffirms the recently evolving discussion that cataract surgery alone also effectively lowers pressure in patients with open angle glaucoma, though there were some minor observed study limitations that clearly favored the control group, making these results even more impressive for the Hydrus group."
The Hydrus II study was conducted at eight research centers in Europe and included 100 patients with mild to moderate open angle glaucoma also undergoing cataract surgery.
On average, patients entering the study had IOP of 18 and were taking two eye drops to control that pressure. They were instructed to stop taking their eye drops one month prior to the surgery, and had an average IOP of 27 on the day of surgery. They were randomized to undergo cataract surgery alone or cataract surgery along with implantation of the Hydrus device in a concurrent procedure.
At 11 months' follow-up, patients in the treatment group had IOP of 16.0 on 0.4 medications, while patients in control group were at 15.8 on 0.9 medications, meaning a patient was more than two times more likely to need eye drops in the control group during the follow-up period.
All subjects who were on medications were then instructed to stop taking medication for a month. With topical medications removed, at 12 months, 92 percent of Hydrus patients had an IOP decrease of 20 percent or more versus preoperative levels. When IOPs were divided into quartiles, patients with the highest IOPs were seen to benefit the most from the device. Comparing the two quartiles of highest IOP, the study found that the Hydrus device lowered IOP by 3.5 points more than cataract surgery alone.
While both the Hydrus II study and the Hydrus IV U.S. premarket approval trial are independently evaluating Hydrus in glaucoma patients who are undergoing cataract surgery, the device is being used both in cataract surgery and in standalone glaucoma surgery outside of the United States.