Study finds drug-eluting punctum plug safe, effective

May 1, 2014

In a multicenter phase II study of cataract surgery patients, recipients of a dexamethasone-releasing punctum plug (Ocular Therapeutix) were significantly more likely than their vehicle-treated counterparts to be free of pain and anterior chamber cells at various postoperative follow-up visits.

Take Home

In a multicenter phase II study of cataract surgery patients, recipients of a dexamethasone-releasing punctum plug (Ocular Therapeutix) were significantly more likely than their vehicle-treated counterparts to be free of pain and anterior chamber cells at various postoperative follow-up visits.

 

By Cheryl Guttman Krader; Reviewed by Michael J. Endl, MD

Niagara Falls, NY-Positive results were achieved in a phase II study investigating the efficacy and safety of a dexamethasone-releasing absorbable punctum plug (Ocular Therapeutix) for controlling pain and inflammation after cataract surgery. Now, patient enrollment in two pivotal trials is expected to begin soon, said Michael J. Endl, MD.

Study explaination

The double-masked phase II study enrolled 60 patients at 4 centers. Adults undergoing routine cataract surgery having no ocular comorbidities were randomly assigned to receive the sustained-release dexamethasone device or a vehicle-containing punctum plug inserted in the inferior vertical canaliculus of the operated eye at the end of the procedure.

Follow-up visits were conducted on postoperative days 1, 4, 8, 11, 14, 30, and then every 15 days thereafter when needed to ascertain absorption of the plug.

Efficacy assessments showed the dexamethasone punctal plug was significantly superior to vehicle control in clearing inflammation (anterior chamber cells), reducing the need for rescue medication, and eliminating postoperative pain.

Absence of anterior chamber cells was identified in 34.5% of patients with the dexamethasone plug, but in only 3.4% of controls on day 14. On day 30, anterior chamber cells were absent in 62.1% of eyes in the dexamethasone group and 13.8% of controls. Rescue medication for inflammation control was initiated at the discretion of the investigator during the study for 21% of patients with the dexamethasone punctum plug and for 77% of controls.

 

Takeaways

The proportion of patients reporting no pain was significantly greater in the dexamethasone group at all postoperative follow-up visits through day 30, with the magnitude of the between-group difference ranging from 45% to 59%.

The device was well-tolerated, and there were no remarkable safety concerns.  Notably, there were no occurrences of a long-term postoperative intraocular pressure spike in any of the dexamethasone-treated patients.

“Compliance with postoperative medications may be the biggest obstacle to success of modern cataract surgery,” said Dr. Endl, associate professor of ophthalmology, State University of New York, Buffalo, and partner, Fichte, Endl, & Elmer Eye Associates, Niagara Falls, NY. “In the older population of cataract surgery patients, the challenges include both remembering to use the medications as directed and being able to instill them properly.

“The sustained-release dexamethasone punctum plug is an exciting development toward reducing the need for topical anti-inflammatory drops after cataract surgery and the drawbacks associated with their use,” he continued.

The intracanalicular plug is made of hydrogel and delivers dexamethasone at a sustained rate for the first 2 weeks following insertion and then at a tapering rate for the next 14 days. Pharmacokinetics data from preclinical studies show that the pattern of release predictably maintains a therapeutic concentration of the corticosteroid in the tear film for the first 14 days while still reducing the total burden of drug exposure compared with a conventional topical drop regimen.

The punctum plug showed good retention, but time to disappearance varied. During the study, the plug was retained in all eyes at the 14 day visit, and was present in 97% of patients at postoperative day 30. Subsequent evaluations showed persistence for up to 2 months in some patients.

 

 

Michael J. Endl, MD

E: mpderme@aol.com

Dr. Endl received research funding from Ocular Therapeutix as an investigator in the Phase 2 trial, but he has no other relevant financial interests to disclose.