July 2019

IN FOCUS

MIGS Update
CyPass: One year after its voluntary withdrawal


by Liz Hillman EyeWorld Senior Staff Writer


CyPass placed
appropriately


CyPass placed poorly, which could increase the risk of endothelial cell loss
Source (all): Leon Herndon, MD

At a glance

• Glaucoma specialists describe the void that the CyPass withdrawal left in the MIGS space.
• Five-year data showed endothelial cell loss in a clinically significant number of patients, prompting Alcon to voluntarily withdraw CyPass—the only FDA-approved MIGS device that facilitated aqueous outflow into the suprachoroidal space—from the market.
• Glaucoma specialists would like to see CyPass or a similar device return to the market and describe how they would fit it in their armamentarium of MIGS options.
• Some monitor CyPass patients with gonioscopy and pachymetry, while others advocate for regular endothelial cell counts.

In August 2018 Alcon voluntarily withdrew CyPass Micro-Stent, a MIGS device placed in the supraciliary space to drain aqueous from the anterior chamber into the supraciliary and suprachoroidal space via the uveoscleral pathway, from the market due to the potential for endothelial cell loss.
Nearly a year later, ophthalmologists share how they’ve communicated with patients, how they’re monitoring patients and have managed cases with endothelial cell loss, and the void created by this device’s withdrawal from the market.
CyPass took advantage of the untapped suprachoroidal space, while other MIGS devices facilitate drainage into the trabecular meshwork or subconjunctivally. Leon Herndon, MD, said most trabecular meshwork options did not get pressures as low as he wanted and traditional subconjunctival surgeries—trabeculectomy and tube shunts—carry a higher risk profile.
“I was excited about the suprachoroidal space because there was the potential for the very low pressures that I wanted,” Dr. Herndon said. “I don’t know that I’ve found anything yet in the angle to replace the pressure lowering that we often saw with CyPass.”
Alcon voluntarily withdrew CyPass from the market when 5-year follow-up from its COMPASS-XT study showed more than 30% endothelial cell loss in 27.2% (44/162) of patients who had received the device.1 According to a Safety Communication issued by the FDA after Alcon’s voluntary recall, the endothelial cell loss rate appeared to be related to the number of visible retention rings extending to the anterior chamber.2 An ASCRS CyPass Withdrawal Task Force was formed and issued a preliminary statement about the study findings, withdrawal, and diagnostic monitoring.3
Dr. Herndon noted that of the patients in the COMPASS trial who had significant endothelial cell loss, very few had clinical findings. He also said that none of the patients in this trial required corneal surgery at the time of the 5-year data.
Douglas Rhee, MD, said he finds the withdrawal from the market a “definite loss.”
“Frankly, I miss it,” Dr. Rhee said. “I understand the safety concerns, but with everything in medicine, you’re balancing. You’re balancing the risk of going permanently blind from glaucoma versus a certain percentage of patients who could have corneal endothelial cell changes. … Maybe years later some of them may need an endothelial cell transplant. In that sense, I certainly don’t advocate being cavalier or disregarding potential complications, but we already have procedures and devices that can change the corneal endothelium, particularly tube shunts. Is CyPass the best procedure for extremely early glaucoma? Maybe not from what we’ve learned about the endothelial cell loss, but it’s something that I miss from our armamentarium, and I hope that the other manufacturers exploring this space will be successful.”
Since its withdrawal, Dr. Rhee said he has been using the Hydrus (Ivantis) more, but he pointed out that it’s a trabecular meshwork bypass procedure—a different space. Dr. Herndon said he had decreased his use of the CyPass prior to the recall because he had experienced unpredictable myopic shifts with some patients.
When it comes to trimming the CyPass device, should it be sticking out more than intended in the anterior chamber, Dr. Rhee said revision needs to be carefully weighed against the status of the corneal endothelium.
“A good discussion needs to be had with the patient about the risks with revision against the risk of potential endothelial cell transplant,” Dr. Rhee said. Such revision, he continued, is presumed to stop endothelial cell decline, but at this point, we don’t know. “We don’t know what causes the cell loss, but we think it’s mechanical. The presumption is if you trim it, the decline will stop,” Dr. Rhee said.
Dr. Herndon said he and his colleagues sent letters to patients who had received the CyPass, explaining in simple terms the potential for corneal damage and offering to see them in clinic. Dr. Herndon said he revised two CyPass devices that were too long but there was no evidence of corneal damage; in both cases he was going in to do another glaucoma procedure.
From a cornea specialist’s perspective, Edward Holland, MD, said he thinks patients should be followed with periodic endothelial cell counts. If CyPass is extending more than desired into the anterior chamber, endothelial cell counts could inform the surgeon if the device should be trimmed. If the cell count is good, the patient could be followed every 6 months to monitor for change and consider revision, if necessary, Dr. Holland said.
“The question then becomes if the device is in a good position or if it’s already been trimmed—what’s the value of a cell count because then there is nothing to do at that time if the patients are progressing with losing cells,” he said.
“I feel strongly that information is valuable, and the patients and their families would like to know. Endothelial cell count is the only screening test that can predict the risk of corneal edema. Changes in pachymetry and on slit lamp examination can only document corneal edema and by then it’s too late. I would advocate for endothelial cell counts on a regular basis for all of these patients,” Dr. Holland said later.
Dr. Herndon said he does not routinely get specular microscopy for endothelial cell density on these patients but will perform careful gonioscopy, will look at pachymetry, and will act accordingly.
Overall, Dr. Rhee said he would like to have CyPass back on the market and he doesn’t need any additional safety data to be comfortable with it, though, of course, more data would be nice.
“I think we could return it to the market, and I would just change it in my lineup. It would be worthy to reevaluate where in the armamentarium it would be optimally used,” he said, explaining that while such a device might not be good for ocular hypertension or early stage glaucoma patients, it is a lower risk option than a trab or tube shunt.
Dr. Herndon expressed a similar sentiment.
“The argument could be made that we usually reserve traditional procedures—trab and tube shunts—for patients with more severe disease where the risk-benefit ratio is leaning toward doing more advanced procedures,” he said. “In someone with less advanced disease, the argument could be made that you don’t want to subject these patients to the risk of corneal injury down the road.”
Dr. Herndon said he’d like to see CyPass or something similar come back to the market. If it did, he said there would need to be an educational campaign about how to place such devices properly.
For Dr. Holland, it’s a discussion that’s needed among the surgeon, patient, and their family.
“I think we have to have informed consent for the patient about the risk of cell loss and let the doctor, the patient, and the family decide together,” he said. “I’m not opposed to the device, but I think everyone should know what the risks are.”

Editors’ note: Dr. Herndon and Dr. Rhee were part of the ASCRS CyPass Withdrawal Task Force.

The ASCRS CyPass Withdrawal Task Force suggested gonioscopy to evaluate any contact between the device and corneal endothelium, the position of the device lumen anterior to Schwalbe’s line, and the number of retention rings visible in the anterior chamber. Slit lamp examination to assess focal or diffuse corneal swelling and/or guttata was also recommended. Pachymetry and specular microscopy could be considered, the statement read. Only clinical monitoring was recommended by the task force when 0–1 ring of the device was visible in the anterior chamber. The task force advised monitoring, though perhaps more frequently, in eyes with 2–3 rings visible but with no clinically significant corneal decompensation. If there is corneal decompensation with more than 1 ring visible, trimming the proximal end was listed as the preferred intervention, with deeper implantation considered safe within 7–10 days after implantation. The task force expressed concern about device removal due to fibrosis.

Financial interests

Herndon: Alcon, Glaukos, Sight Sciences, New World Medical
Holland: None
Rhee: None

Contact information
Herndon
: leon.herndon@duke.edu
Holland: eholland@holprovision.com
Rhee: dougrhee@aol.com

About the doctors

Leon Herndon, MD
Professor of ophthalmology
Chief of the Glaucoma Division
Duke University School of Medicine
Durham, North Carolina

Edward Holland, MD
Director of Cornea Services
Cincinnati Eye Institute
Professor of clinical ophthalmology
University of Cincinnati

Douglas Rhee, MD
Chair
Department of Ophthalmology and Visual Sciences
Case Western Reserve University
Cleveland

References

1. Lane S. Overview of the results from the 5 yr follow up study of the CyPass MicroStent. ESCRS Scientific Presentation. Sept. 24, 2018.
2. Update: Potential eye damage from Alcon CyPass Micro-Stent used to treat open-angle glaucoma. FDA Safety Commission. Oct. 24, 2018. Accessed May 14, 2019. www.fda.gov/medical-devices/safety-communications/update-potential-eye-damage-alcon-cypass-micro-stent-used-treat-open-angle-glaucoma-fda-safety.
3. Preliminary ASCRS CyPass withdrawal consensus statement. ASCRS CyPass Withdrawal Task Force. September 2018. Accessed May 15, 2019. ascrs.org/
CyPass_Statement.

CyPass: One year after its voluntary withdrawal CyPass: One year after its voluntary withdrawal
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