Sustained-Release Bimatoprost Lowers Intraocular Pressure

Caroline Helwick

November 18, 2015

LAS VEGAS — A biodegradable sustained-release bimatoprost implant (Bimatoprost SR, Allergan) is safe and effective for the treatment of glaucoma, and could change the treatment paradigm for the disease, according to investigators involved in a phase 1/2 trial.

The implant was developed to address the problem of nonadherence in glaucoma, said Richard Lewis, MD, from Sacramento Eye Consultants in California. And the results are promising — it "provided rapid and sustained lowering of intraocular pressure."

Dr Lewis reported 6-month interim results on 75 glaucoma patients from the 24-month trial, deemed a Best of AAO poster, here at the American Academy of Ophthalmology 2015 Annual Meeting.

The implant is administered using a prefilled, single-use applicator system. After intracameral injection, it can be visualized in the inferior iridocorneal angle, where it slowly elutes the drug and then biodegrades.

The study participants received the bimatoprost implant — at doses of 6 µg, 10 µg, 15 µg, or 20 µg — in one eye. Their second eye, which was treated with daily topical bimatoprost 0.03%, served as the control eye.

The primary end point of the study was change in intraocular pressure from baseline. The use of rescue medication and patient safety were other key outcome measures.

Mean intraocular pressure was similar in the implant and control groups at baseline (25.2 vs 24.5 mm Hg).

The overall reduction in intraocular pressure from baseline to week 16 ranged from 7.2 to 9.5 mm Hg in eyes that received a single implant, which was similar to the mean reduction of 8.4 mm Hg seen in the control eyes.

Intraocular Pressure at 6 Months

The reduction in intraocular pressure in the implant group was clinically significant out to 6 months (P < 0.001). And by month 6, more than 70% of the implant eyes had not required topical pressure-lowering rescue medication or a second bimatoprost injection.

Dr Lewis reported that the issue of how long the implant is effective is still being evaluated. "At 12 months, there is still some residual effect, but the implant may or may not be delivering drug. We are still working out when the next implant would be needed," he told Medscape Medical News.

The most common ocular adverse effects were conjunctival hyperemia and foreign body sensation in eyes.

There are a number of significant advantages of the implant over conventional drugs.

There were more events in the implant eyes than in the control eyes; however, "they resolved quickly and were likely related to the injection procedure," said Dr Lewis.

There were no serious ocular adverse events in any implant eyes. The one retinal detachment that occurred in a control eye was considered to be unrelated to treatment.

The implant eliminates the typical minor adverse effects of topical medications, such as redness, Dr Lewis pointed out. Rates of conjunctival hyperemia and erythema of the eyelid were more than twice as high in the control eyes as in the implant eyes.

"There are a number of significant advantages of the implant over conventional drugs," he said.

An implant would be of great benefit, said Kenneth Kato, MD, from Tallahassee Eye Associates in Florida.

"We have patients who lie about being compliant with their glaucoma medications. To have something easy like this, that you implant in the office, would be great," he told Medscape Medical News.

Several types of implants are in development, including nanoparticle-based products, Dr Kato pointed out.

"These products would all be one dose that gives a long-term effect, which would be great for compliance," he added. "There's definitely a role for them."

The study was sponsored by Allergan. Dr Lewis is a consultant for Allergan and numerous other companies. Dr Kato has disclosed no relevant financial relationships.

American Academy of Ophthalmology (AAO) 2015 Annual Meeting: Abstract PO093. Presented November 15, 2015.


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