The voluntary withdrawal of Alcon’s CyPass Micro-Stent from the global market is a timely reminder of the importance of ongoing safety monitoring for new devices, says Dr. Mitchell Lawlor, Sydney glaucoma surgeon and neuro-ophthalmologist.
The CyPass Micro-Stent was withdrawn on 29 August 2018 with surgeons asked to immediately cease its further use for implantation and return any unused devices to Alcon.
The decision was based on an analysis of five-year post-surgery data from the COMPASS-XT long-term safety study.
The US Food and Drug Administration (FDA) approved the CyPass Micro-Stent in July 2016 for use in conjunction with cataract surgery in adult patients with mild-to-moderate primary open-angle glaucoma, based on the results of the landmark two-year COMPASS study. The COMPASS study demonstrated a statistically significant reduction in intraocular pressure at two years post-surgery in subjects implanted with the CyPass Micro-Stent at the time of cataract surgery, as compared to subjects undergoing cataract surgery alone. At two years post-surgery, there was little difference in endothelial cell loss between the CyPass Micro-Stent and cataract surgery-only groups, and results were consistent with peer-review literature benchmarks of cataract-related endothelial cell loss.1,2
Alcon has announced an immediate, voluntary market withdrawal of the CyPass Micro-Stent from the global market
The COMPASS-XT study was designed to collect safety data on the subjects who participated in the COMPASS study for an additional three years, with analysis of the completed data set at five years post-surgery. At five years, the CyPass Micro-Stent group experienced statistically significant endothelial cell loss compared to the group who underwent cataract surgery alone.
“The mechanism has not been definitively shown, but most likely it relates to mechanical contact with the corneal endothelium at the drainage angle,” said Dr. Lawlor. “The early information we have from Alcon suggests that the longer the device is in the anterior chamber, the higher the rate of endothelial cell loss.”
Dr. Lawlor said all intraocular surgery causes endothelial cell loss, however “the finding of this five year data was a statistically significant greater loss of endothelial cells in the cataract and CyPass arm than the cataract only arm.
“Any device that potentially has contact anterior to Schwalbe’s line could cause endothelial cell loss – in the Tube Versus Trabeculectomy study, at five years 17 per cent of Baerveldt tubes had some form of corneal oedema.”
Asked about the advice optometrists should offer patients who have had a Cypass Micro- Stent implanted, Dr. Lawlor said, “We don’t have enough information yet to understand the full implications: we need to know the magnitude of the additional endothelial cell loss to understand whether this loss will become clinically significant ie. whether it will cause corneal decompensation and reduced vision. We await more information from Alcon.”
He added, “While surgeons (and patients) may have an enthusiasm for the new, such technology by definition does not have the same evidence base as established surgical techniques. Ongoing collection of registry data as part of post marketing surveillance should be a high priority in this setting.”
Dr. Stephen Lane, Chief Medical Officer, Alcon said the CyPass may be returned to the market in the future. “We believe that withdrawing the CyPass Micro-Stent from the market is in patients’ best interest and is the right thing to do,” he said “Although we are removing the product from the market now out of an abundance of caution, we intend to partner with the FDA and other regulators to explore labelling changes that would support the reintroduction of the CyPass Micro-Stent in the future.”
References
- Reuschel, A., et al., Comparison of endothelial changes and power settings between torsional and longitudinal phacoemulsification. J Cataract Refract Surg, 2010. 36(11): p. 1855-61.
- Buys, Y.M., et al., Prospective randomized comparison of one- versus two-site Phacotrabeculectomy two-year results. Ophthalmology, 2008. 115(7): p. 1130-1133 e1.
