WASHINGTON -- An FDA panel voted unanimously on Friday to recommend approval of the first retinal prosthesis device intended to help nearly blind patients regain a small part of their vision.
The 19-0 vote to recommend approval of the Argus II Retinal Prosthesis device came after study results showed previously blind patients had functional vision with the device. But members of the FDA's Ophthalmic Devices Panel of the Medical Devices Advisory Committee did express some concern about the device's safety.
A single-arm feasibility study of 30 patients showed the Argus II improved visual acuity and daily function including walking straight on a sidewalk (18 of 27 patients) and noticing the direction a person in front of them is walking (25 of 27 patients).
"In most cases the 'on' is consistently outperforming the 'off,' " said panelist Mae Gordon, PhD, of the Washington University School of Medicine in St. Louis. "The data are very clear."
The Argus II is designed for use by patients with severe to profound retinitis pigmentosa, who experience progressive vision loss often leading to blindness. Roughly 1,300 patients a year develop the condition.
The device, manufactured by Second Sight Medical Products, is a three-part system. It includes a video camera attached to a pair of eyeglasses, a processing unit, and an implanted retinal prosthesis.
The glasses capture images, which are sent to the processing unit worn on a belt. The processor transforms the images into an electrical stimulation pattern that's sent to the implanted retinal prosthesis. The Argus II gained approval in Europe last year.
In the study, 15 of 16 patients studied were able to localize a square a year after the device was implanted. Half of the 30 patients read 8.9-inch letters from 12 inches away.
Consumer representative Larry Leguire, PhD, and others expressed concern about the number of adverse events in the small number of patients. There were 140 nonserious adverse events in the 30 patients.
Eleven of the 30 reported a serious side effect, defined as permanent impairment or medical intervention to ameliorate the adverse event. Seven of those patients needed a "minor" intervention including an antibiotic injection and other procedures.
Nine of the 30 patients in the trial needed a follow-up surgery to treat adverse events, the FDA said.
Panelists also struggled to balance the Argus II's safety concerns with the fact that they're dealing with already blind or nearly blind patients.
"This is a patient group that has no other option," said Bill Swanson, PhD, from the Indiana University School of Optometry. "Even if it isn't reliable, they and their doctor may still take the risk."
During the public comment period of Friday's meeting, several patients implanted with the device were moved to tears when they spoke about how the Argus II helped them see fireworks for the first time or recognize the face of a loved one they hadn't seen in years.
Some panelists expressed concern that the device under consideration is slightly different from that implanted in the 30 patients studied. The FDA has determined the changes Second Sight submitted won't introduce any new safety concerns, but the agency can't predict how they will impact performance.
Gordon and other panelists said because the new device reflects improvements on the original's shortcomings, the one the panel voted on Friday should be free of concerns.
Panelists strongly agreed there should be a considerable post-approval study to track possible safety concerns.
Draft labeling language for the device warns of a "cascade" of adverse events following an initial minor side effect, the briefing document released in advance of the meeting stated. Four patients in the study experienced this, including the youngest patient studied, a 27-year-old woman, who ended up with a detached retina.
The FDA reminded panelists that the applicant hasn't submitted any details on a possible post-approval study should its device gain clearance. Second Sight said it would use the same post-approval study currently being used in Europe, a nonrandomized, controlled study for a 1-year follow-up.
But the long-term effectiveness of the device isn't in question, the applicant said Friday.
"Clinically, we have not seen a decline and we've followed some patients for 5 years," said Second Sight consultant Lyndon da Cruz, PhD, MBBS, of the Moorfields Eye Hospital and University College in London.
The FDA is not bound to follow the recommendation of its advisory committees, but it often does.