Retention, safety profile
During the initial 6-month study, 88.5% of the devices remained in place, with 94.7% retention during the extension period. There were no cases in which the patient was not aware that the ring had become dislodged.
Patients in the initial trial were randomly assigned to either the bimatoprost insert plus artificial tears or an inert ring plus timolol 0.5% eye drops. Patients in the bimatoprost arm showed a consistent 4 mm Hg to 6 mm Hg reduction in IOP.
At the end of the initial study, patients were eligible to continue for another 13 months and two successive device replacements. Patients in the timolol arm in the initial study used the bimatoprost insert during the open-label extension.
Both the patients who continued using the ring and those who switched to the ring showed a sustained reduction in IOP of 4 mm Hg to 5 mm Hg when the inserts were replaced as designed out to 19 months.
A total of 115 patients completed the initial study. Because of the approval timing for the extension study, some patients completed the first study before the extension began. A total of 75 patients enrolled in the extension. Of this initial group, 65 completed the first 7-month extension and 63 completed the entire 13-month extension.
The safety profile out to 19 months was good, Dr. Brandt reported, and consistent with data from earlier phase I and phase II data. Treatment emergent adverse events were consistent with bimatoprost exposure, including conjunctival hyperemia (21.3%), eye discharge (21.3%), punctate keratitis (16%), increased lacrimation (13.3%), blurred vision (12%), eye puritis (10.7%), foreign body sensation in the eyes (8%), ocular discomfort (8%), dry eye (6.7%), and eye irritation (6.7%).
The only ocular serious adverse event was decreased visual acuity in a patient who developed a cataract not related to treatment.
“The main issue with sustained-delivery platforms is balancing safety with efficacy,” Dr. Brandt said. “While some of the more invasive sustained delivery platforms look to be very safe in a controlled clinical trial, there is an underlying risk of infections and other complications which increases with the invasiveness of the platform, especially in the real world.
“If you look at the universe of patients being treated with pressure-lowering medications, the vast majority have early glaucoma or early ocular hypertension, he added. In these patients, glaucoma is a relatively slowly progressing disease. The last thing you want to do is place a patient at risk of a complication when they have little risk of ever being impaired by glaucoma.”