By Fred Gebhart
The loss of visual acuity associated with glaucoma may be an indirect result of increased IOP. But increased IOP is rarely the result of excessive aqueous production. It is usually an insufficiency in aqueous outflow.
“While the disease occurs at the back of the eye, virtually all of our treatments effect the front of the eye,” said Stephen Vold, MD, founder and CEO of Vold Vision, Fayetteville, AR. “All of our treatments for glaucoma deal with the aqueous in some manner.”
Dr. Vold introduced “New Horizons in Glaucoma Devices.” Glaucoma devices employ four broad outflow strategies: via Schlemm’s canal, into the supraciliary space, trans-scleral/subconjunctival outflow, or cilioablative. Nine companies presented their latest data and products.
Listen as each of the nine companies present their glaucoma device technologies.
Glaukos’ original iStent is the smallest medical device approved by the FDA, said Bruce Nogales, chief corporate development officer. The next generation, iStent Inject, is about one-third the size of the original and is a solo device. The iStent is used with cataract surgery.
“We saw dramatic reductions in IOP with iStent Inject,” Nogales said. “Two-thirds of patients had an IOP of 18 mm Hg or lower at 12 months with no medication and 84% had 18 mm Hg or lower with a single medication.”
The company is enrolling patients for a pivotal IDE trial. Glaukos is developing a third-generation device, the iStent Supra, which drains into the suprachoroidal space.
Ivantis calls its Hydrus MicroStent the first “intracanalicular scaffold” for primary open-angle glaucoma. The 7-mm stent is inserted into Schlemm’s canal to increase outflow by dilating and stabilizing the canal structure.
The company has already treated over 1,800 patients in clinical trials or registry studies at more than 70 global sites. An IDE study, Hydrus 4, with more than 550 patients, should be completed by mid-year. A European study with Hydrus 2 showed a roughly 40% reduction in IOP using the same trial design as Hydrus 4.
“This device combines the advantages of conjunctiva sparring ab interno trabecular bypass with canal scaffolding and dilation,” said Brett Trauthen, chief scientific officer. “We saw a very robust IOP reduction that persisted through the second year.”
iSTAR Medical aims to augment the natural uveoscleral outflow using STARflo, a silicone device with 27-µm pores. The head of the device extends into the anterior chamber with the body curving through the sclera to the suprachoroidal space.
The company is working with FDA on an IDE study, making its case with international data showing up to a 61% reduction in IOP at 6 months and 60% at 12 months. The blebless device requires ab externo surgery. An ab interno injectable MINIJect is under development.
“Because our silicone material is anti-fibrotic and anti-inflammatory, we strongly urge surgeons not to use mitomycin C or other antifibrotic agents during implantation,” said CEO Michel Vanbrabant. “The device itself takes care of those problems.”
Transcend Medical has taken the CyPass Micro-Stent through eight generations in more than 1,000 patients. The stent drains directly into the suprachoroidal space, which offers a large absorptive capacity and a natural pressure gradient to drive outflow. Non- FDA studies show a 35% reduction in IOP at 24 months when used with phacoemulsification and slightly less when used alone.
The pivotal COMPASS trial is fully enrolled with 505 patients, said Sean Ianchulev, MD, chief medical officer with initial data due later this year.
The next generation is the CyFlo Vx Infusion System, an injectable system that creates a reservoir to increase absorptive capacity. One-year results show 10 mm Hg drop in IOP compared to a 7 mm Hg drop using CyPass alone.
“Stent technology is a familiar modality in cardiovascular, pulmonary, gastrointestinal and other specialties,” Dr. Ianchulev said. “In ophthalmology, stent technology is the next frontier.”
AqueSys has a gel stent, Xen, which bypasses the trabecular meshwork to create its own outflow into the subconjunctival space. The 6-mm stent is about the diameter of a human hair and uses flow mechanics to prevent hypotony.
The internal bleb becomes a low-lying drainage area with fewer post-op complications and management issues than ab externo dissected blebs, said Ron Bache, president and CEO. International data show a mean IOP reduction of 40% with a simultaneous 73% reduction in medication use. The device is used more often as a solo procedure (54%) in Europe versus a combination cataract procedure (46%). The company hopes for U.S. marketing approval by late 2016.
“Minimally invasive is important in devices, but it is not enough,” Bache said. “You need proven efficacy and the ability to intervene early. We give you all three in bypassing existing obstructions and introducing a new outflow pathway.”
InnFocus showed a dramatic drop IOP from 23 mm Hg pre-insertion to 10.9 mm Hg at 3 years in multinational studies. Patients went from a mean of 2.8 medications to 0.5 medications over the same 3 years and 73% of patients were medication free. The company is enrolling for a 439-patient IDE study comparing its MicroShunt against trabeculectomy. Reimbursement codes are already in place.
“Our MicroShunt can be used anywhere along the clinical pathway in glaucoma,” said Russ Trenary, president and CEO. “We want physicians to think low IOP and this is a way for them to get there.”
New World Medical is using research and marketing expertise gained with its Ahmed Glaucoma Valve to develop a novel device to improve outflow by removing a precise strip from the trabecular meshwork.
The Kahook Dual Blade (KDB), originally developed to harvest cadaver for research by Malik Kahook MD, the Slater Family Endowed Chair in Ophthalmology at the University of Colorado, Denver, uses twin blades to free juxtacaniular trabecular meshwork and open outflow with minimal collateral damage.
Clinical trials are slated to begin this summer, said Suhali Abdullah, director of research and development at New World Medical. The KDB is covered by existing reimbursement codes and can be used with or without cataract surgery to natural drainage.
Eye Sonix has more than five years of treatment experience without a single significant adverse event. That safety record comes with greater than 20% reduction in IOP at 12 months in both naïve eyes and in combination with medication.
“We have a significant decrease in IOP, which is both sustainable and repeatable,” said Don Schwartz, MD, founder and CEO. “It can be used as an initial treatment or as an adjunct to pharmaceutical agents.”
The current prototype unit delivers ultrasonic energy to a 1-mm treatment zone that encompasses the trabecular meshwork, open angle, and Schlemm’s canal at 12 locations around the eye. Ultrasound induces hyperthermia and sonomechanical vibrations that loosen blockages in the trabecular meshwork and trigger cytokine cascades to help reduce IOP.
EyeTechCare delivers ultrasonic energy using a suction cone coupled to the cornea. Energy is delivered to six 1-mm treatment areas around the eye. Ultrasonic energy removes the epithelial layers while preserving the underlying stroma.
Three multicenter prospective studies have treated more than 1,500 patients. Patients show nearly a 30% reduction in IOP at 1 year with minimal safety concerns. The device is available in the EU.
“The eyes are typically quiet after treatment,” said CEO Dietrich Wolf, PhD. “We never saw any major adverse events and visual acuity stays as it was before treatment.”