Eyeworld

33 EW GLAUCOMA by Stefanie Petrou Binder, MD, EyeWorld Contributing Writer Practical implantation and postop tips for the XEN implant An expert discusses early experience with the gel stent I nnovative devices for use in microinvasive glaucoma sur- gery (MIGS) are proving to be highly effective in achieving sustainable IOP reductions in glaucoma patients maxed out on drops. The XEN Gel Stent (Allergan, Dublin, Ireland), approved in the U.S. since early 2017, has attracted attention due its relatively small surgical learning curve and its high potential to elicit marked changes in IOP due to its use of the untapped subconjunctival space. At the 2018 World Ophthalmology Congress, Ahmed Elkarmouty, FRCS, Moor- fields Eye Hospital, London, U.K., reviewed the XEN implant so far and discussed his experience in 25 of his own patients. Dr. Elkarmouty was an early adopter of the XEN. "The XEN implant redirects aqueous flow from the anterior chamber to the subcon- junctival space," he said. "It is the only ab interno MIGS approach that can create conjunctival drainage. The implant bypasses the trabec- ular meshwork and creates a new subconjunctival outflow pathway in individuals with primary open angle glaucoma who are not well managed on drops." Patient selection Dr. Elkarmouty applies the XEN in patients eligible for trabeculectomy, showing a particular preference for this technology in certain patient groups, such as very young patients in whom he may want to cut down the fear factor and who have health- ier conjunctiva; very old patients in whom XEN implantation is far less invasive with less intense aftercare; high myopes in which there is a high chance of hypotony following trabeculectomy and in whom trabe- culectomy poses a risk of choroidals and macular folds; patients with a higher risk for developing uveitis; patients with a friable conjunctiva in whom conventional trabeculec- tomy or tube insertion may be difficult; glaucoma patients need- ing cataract surgery; patients with back pain who cannot have general anesthesia or tolerate lying supine for longer periods; and patients who have expressed the desire to be drop-free and choose a less invasive surgical option over trabeculectomy. He conducted a study that included 25 patients (mean age 72 years; range: 39–95 years), of which 14 were Caucasian, nine were Black, and two were Asian. The patients each were on treatment regimens that included an average of three drops. Their mean IOP was 23±8 mm Hg, ranging from 14 mm Hg to 40 mm Hg. The patients underwent XEN stent implantation under local anesthesia using a sub-Tenon's block with lignocaine. Before implanta- tion, Dr. Elkarmouty administered 0.1 mL of high dose anti-scarring agent in the subconjunctival space at 12 o'clock, which he spread across to the supra-nasal quadrant using spears. The XEN implant is 6 mm in length with a 45 µm diameter. Inser- tion involves a preloaded disposable 27-gauge injector via a self sealing corneal incision. The surgeon cross- es the anterior chamber to the upper January 2019 Rho kinase continued from page 32 years to come out, Dr. Rhee noted. The corneal deposits with netar- sudil are within the epithelium, can pop up within a few weeks to a few months, and if you stop the medica- tion, are gone within 1 week. There is also no visual impact in either case, he stressed, adding that while this does happen in a decent num- ber of patients, it is not something that has affected his prescribing patterns. Such corneal deposits were also visually insignificant in the clinical trial, Dr. Bacharach noted. One other side effect that can occur with the drug is micro-hem- orrhages in the conjunctiva. "Most of the time they are only seen under the microscope and are related to the effect of the drug because rho kinase inhibition can relax the cells that line blood vessels as well, and these fine capillaries might be related enough to cause very small micro-hemorrhages," Dr. Bacharach said, adding that in most cases, these were visually insignificant, with less than 1% of the people in the trial discontinuing the medica- tion due to this issue. In addition to the single agent netarsudil, a fixed combination of netarsudil and latanoprost, known as Roclatan (Aerie Pharmaceuticals), is currently under FDA review, Dr. Bacharach noted. "That drug would be the first fixed combination in the U.S. with a prostaglandin in it," he said, adding that this has been the only clinical trial with a fixed com- bination containing a prostaglandin that has been able to reach superior- ity over each individual component. The side effect profile of the fixed combination looked similar to what would be expected with each of the individual components. "It did not appear that there was significant additivity or different side effect profiles," Dr. Bacharach said. EW References 1. Kazemi A, et al. The effects of netarsudil ophthalmic solution on aqueous humor dy- namics in a randomized study in humans. J Ocul Pharmacol Ther. 2018;34:380–386. 2. Kiel JW, Kopczynski CC. Effect of AR-13324 on episcleral venous pressure in Dutch belted rabbits. J Ocul Pharmacol Ther. 2015;31:146– 51. 3. Serle JB, et al. Two phase 3 clinical trials comparing the safety and efficacy of netarsudil to timolol in patients with elevated intraocular pressure: rho kinase elevated IOP treatment trial 1 and 2 (ROCKET-1 and ROCK- ET-2). Am J Ophthalmol. 2018;186:116–127. Editors' note: Dr. Bacharach has finan- cial interests with Aerie Pharmaceuti- cals. Dr. Rhee has financial interests with Aerie Pharmaceuticals, Alcon (Fort Worth, Texas), Allergan (Dublin, Ireland), Bausch + Lomb (Bridgewater, New Jersey), Glaukos (San Clemente, California), and Ivantis (Irvine, Cali- fornia). Dr. Sit has financial interests with Aerie Pharmaceuticals. Contact information Bacharach: jbacharach@northbayeye.com Rhee: Douglas.Rhee@UHhospitals.org Sit: Arthur@mayo.edu Presentation spotlight continued on page 34 A well-placed XEN implant Source: Ahmed Elkarmouty, FRCS

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