Bimatoprost sustained-release implant significantly reduces IOP with high patient satisfaction

The implant had more ocular adverse events than topical bimatoprost, but those events were related to the injection procedure and resolved quickly.

Issue: August 2016

A biodegradable bimatoprost-eluting implant compared favorably with topical bimatoprost in reducing IOP, according to a scientific poster presented at the European Glaucoma Society Congress in Prague.

Keith R. Martin, MA, DM, MRCP, FRCOphth, reviewed 12-month results of a phase 1/2 clinical trial of the bimatoprost sustained-release implant (Bimatoprost SR, Allergan).

“It’s a very quick and easy procedure to do and very well tolerated by patients. It takes just a few seconds,” Martin told Ocular Surgery News. “We’re really hopeful that this will be a potential treatment that we can use in some of our glaucoma patients in the future.”

The device is injected into the anterior chamber and designed to dispense medication for 4 to 6 months. It is visible in the inferior iridocorneal angle, where it dispenses the drug and degrades slowly.

Four levels of bimatoprost were used in the implant: 6 µg, 10 µg, 15 µg and 20 µg.

About the study

The prospective study included 75 patients with mean age of 63.2 years; 45 patients were phakic, and 30 were pseudophakic.

Bimatoprost SR was implanted in one eye of each patient, and topical bimatoprost 0.03% was instilled in the fellow control eye. Patients underwent washout of all previous ocular hypotensive medication before the baseline visit 1 to 3 days before treatment.

Patients were followed up at 2 and 8 days, 2, 4, 6, 8, 12, 16 and 20 weeks, and 6, 7.5, 9, 10.5 and 12 months.

Primary outcome measures were IOP change from baseline during the first 16 weeks of the study. Safety, adverse events and patient satisfaction were also reported.

Mean baseline IOP was 25.2 mm Hg in study eyes and 24.5 mm Hg in fellow eyes.

Results

Overall mean IOP reduction from baseline through week 16 was 7.2 mm Hg to 9.5 mm Hg in eyes that received the implant, depending on the dosage level, and 8.4 mm Hg in eyes that received topical bimatoprost.

IOP was reduced significantly with all four dosages of bimatoprost dispensed by the implant (P ≤ .05).

A single implant controlled IOP without rescue or re-treatment in 91% of study eyes up to 16 weeks and 41% of study eyes up to 12 months.

The overall incidence of ocular adverse events was higher in eyes treated with Bimatoprost SR. Adverse events that occurred within 2 days after intracameral injection and were related to the injection procedure included conjunctival hyperemia, foreign body sensation, ocular pain, increased tear production and conjunctival hemorrhage. These events generally resolved quickly.

The overall incidence of adverse events with onset later than 2 days after injection was the same in study eyes and fellow eyes. Adverse events typically associated with topical prostaglandin analogues, such as conjunctival hyperemia, were less frequent with the implant.

The implant procedure was less burdensome than expected for 79.7% of patients after initial treatment and 83.3% after re-treatment.

At 12 weeks after treatment, 77.8% of patients were “very or extremely likely” to undergo another implant procedure, and 83.3% of patients were “very or extremely likely” to recommend the implant.

“What we found is that this treatment is very well tolerated by patients. It lowers intraocular pressure at least as effectively as daily administered drops for a period of several months,” Martin said. “And we’ve also shown that the side effect profile is very good relative to the topically administered drop. We look at side effects, for example, after 2 days, so you’re not including the side effects related to the administration of the implant.” – by Michela Cimberle and Matt Hasson

Reference:
Martin KR, et al. Interim 12-month efficacy, safety and patient-reported outcomes in a phase 1/2 trial of Bimatoprost Sustained-Release Implants for glaucoma surgery. Presented at the European Glaucoma Society Congress; May 19-22, 2016; Prague.

For more information:
Keith R. Martin, MA, DM, MRCP, FRCOphth, is professor of ophthalmology at the University of Cambridge, United Kingdom. He can be reached at email: krgm2@cam.ac.uk.

Disclosure: Martin reports he is a consultant for Allergan.