The FDA today released an update to a warning on Novartis (NYSE:NVS) subsidiary Alcon’s CyPass glaucoma stents, saying that clinicians should still refrain from using the stents and should monitor patients who’ve received them for endothelial cell density loss.
In August, Alcon voluntarily pulled the stents from the global market based on an analysis of five-year post-surgery data from the Compass-XT study of the device which showed some patients had significant loss of endothelial cells. Endothelial cells are believed to be vital to maintaining visual functionality, the company said.
The FDA issued a safety communication related to the issue a month later in September, based on a preliminary review of the post-approval study, and cited concerns regarding both significant endothelial cell loss and reductions in endothelial cell density.
In its recent review, the FDA said that at five years, 27.2% of patients implanted with the CyPass device had more than 30% loss in endothelial cell density.
Data also suggests a correlation between the distance the CyPass device extends into the anterior chamber of the eye, as assessed by the number of visible retention rings on the device, and the rate of endothelial cell loss. The results also suggested that the general rate of cell loss does not plateau at five years post-implant.
The federal watchdog said it updated its earlier safety notice based on the review of study data, confirming its earlier suggestions and adding three more.
The agency still urges clinicians to not use the devices and to return them to Alcon, but now also suggests that patients who have been treated with the device should be periodically evaluated to monitor for endothelial cell loss.
The FDA said that eye care providers should evaluate patients with the device to see the number of retention rings visible on the proximal end of the device, and that patients with two or more rings should be evaluated for endothelial cell loss “as soon as possible,” according to the release.
“Based on the endothelial cell density levels, and other factors such as age and time post-implantation, the surgeon should determine if additional surgical interventions (that is, trimming, repositioning, removal) are appropriate,” the agency wrote in its last recommendation.
Novartis’ Alcon won FDA clearance for the CyPass micro-stent, with indications for reducing intraocular pressure in patients suffering from glaucoma, in July 2016.