DRUG-DELIVERY SYSTEMS MAY IMPEDE GLAUCOMA PROGRESSION

IN THE May issue, I discussed drug-delivery contact lenses in the pipeline. This month, I discuss the innovations in sustained-release drug delivery systems in the pipeline that may close the gap between drop non-compliance and surgery.

BIMATOPROST PRODUCTS

A bimatoprost (Lumigan, Allergan) insert and a biodegradable sustained-release implant are under investigation.

The ocular insert/ring is designed for placement between the upper and lower fornices and comes in diameters ranging from 24mm to 29mm with sizing determined by a patient’s intercanthal distance.

The insert demonstrated a sustained reduction in IOP for up to 6 months — and even longer without daily eye drops — with mild adverse events, such as, eye discharge and punctate keratitis, reports a paper presented at the 2017 American Glaucoma Society (AGS) meeting. Further, retention rates were 92.3%, according to the AGS paper. A Phase 2 clinical trial is complete, and Phase 3 trials are expected this year.

The implant is designed for injection into the anterior chamber, visualized in the inferior iridocorneal angle and continuously releases bimatoprost through four to six months. When comparing four different bimatoprost sustained-release implant doses to topical bimatoprost, the implant demonstrated nearly equal IOP-lowering effects at four months, reports a paper presented at the 2016 AGS meeting. In terms of adverse events, conjunctival hyperemia was higher in the implant group, but was related to the injection procedure and graded mild by the investigator. The implant is undergoing Phase 3 clinical trials.

PUNCTAL PLUGS

The punctal plugs composed of travoprost (Travatan Z, Alcon) and latanoprost (Xalatan, Pfizer) are under investigation for safety and efficacy in human subjects. The goal: to place the plugs that have sustained release through 90 days in either or both the upper or lower canaliculus.

TRAVOPROST IMPLANTS

A travoprost extended-release implant and a sustained-release travoprost implant are under investigation.

The extended-release implant is biodegradable, is implanted intracameral and resides in the inferior iridocorneal angle, reports a poster presented at The 2015 Association for Research in Vision and Ophthalmology Annual Meeting. Patients with this implant demonstrated IOP reduction similar to bimatoprost and latanoprost drops, reveals a Phase 2a study.

The sustained-release implant, designed for the nasal anterior chamber angle, anchored behind the trabecular meshwork, is undergoing a Phase 2 clinical trial. The implant continuously elutes travoprost into the anterior chamber.

THE FUTURE

These innovations will provide the drug delivery needed to slow or stop disease progression. OM

DR. SCHWEITZER specializes in advanced glaucoma, refractive surgical clinical care and anterior segment pathology at Vance Thompson Vision. He has had multiple articles published and has delivered lectures on glaucoma, anterior segment pathology, refractive surgical clinical care and surgical management. Email him at justin.schweitzer@vancethompsonvision.com.