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FDA panel recommends Artisan phakic IOL with conditions
The Ophthalmic Devices Panel had questions about the lens’s long-term safety. Presenters cited more than a decade’s experience with the lens in Europe.
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An advisory panel to the Food and Drug Administration last month recommended that the Artisan lens be approved once certain conditions are met. The conditions outlined by the Ophthalmic Devices Panel included changes to the physician and patient labeling for the phakic IOL and a further analysis of the device’s long-term efficacy.
The Artisan IOL is a one-piece lens for the correction of myopia in phakic eyes. It is an elliptical lens, 8.5 mm in overall length. The IOL is manufactured in two sizes: with a 5-mm optic, in lens powers ranging from –5 D to –20 D, and with a 6-mm optic in powers from –5 D to –15 D.
Vance Thompson, MD, one of the investigators in the Artisan lens study, discussed the importance of proper training to implant the lens. Many of the complications recorded in the clinical trials of the lens were due to surgeon error during lens implantation, he said. Proper fixation and adequate anterior chamber depth are necessary to secure a tight fit over the pupil, he said.
Dr. Thompson also addressed the rate of endothelial cell density loss. This issue was of concern to the panel, some of whom noted there appeared to be limited long-term data on the subject.
During the study the protocol changed, Dr, Thompson said, and cell loss was studied in a small group of patients. To support the limited findings reported from the U.S. trials, he cited a large European study that showed initial cell loss that stabilized over time.
The Artisan lens is manufactured by Ophtec BV in the Netherlands and its subsidiary Ophtec USA. Once approved, it will be distributed in the United States by Advanced Medical Optics under the name Verisyse. Outside the United States, it will be distributed by AMO under that name and by Ophtec under the Artisan name.
Dr. Thompson said the Artisan phakic IOL has been available internationally for nearly a decade and is the premiere choice in the international market.
Endothelial cell loss
The panel was evenly split over recommending the lens for approval. Committee chairwoman Jayne S. Weiss, MD, had to vote to split the tie. She voted in favor of the device.
During sponsor and FDA presentations, the panel discussed concerns over the company’s data on endothelial cell density loss and the possibility of visual complications with the device in patients with large pupils.
Regarding pupil size, some members of the panel expressed concern that patients with pupil sizes greater than the lens diameter might experience unwanted photic phenomena.
The panel was concerned about endothelial cell loss because, even though the lens has been in use for over decade, a phakic lens of this type could remain in the eye for many decades. The rate of endothelial cell loss over that span of time is unknown.
William D. Mathers, MD, a member of the panel, reviewed the data from Ophtec and the FDA at the panel meeting. Dr. Mathers suggested that the average candidate for the Artisan would be most likely be over 40 years of age, and might be facing cataract surgery in a few years. He suggested limiting use of the Artisan to patients most in need.
During Ophtec’s presentation of its data, R. Doyle Stulting, MD, PhD, U.S. medical monitor for the lens, discussed how the rate of endothelial cell loss was measured. When the study began in 1997, various instrumentation was permitted by the FDA-approved protocol. The different instruments produced varying results, and the company later decided that the Konan specular microscope was the most accurate instrument. At that time, the protocol was changed to require the use of only that measurement.
In an effort to provide sufficient data, the company conducted a recount of the cell images in selected patients. The company recounted the images from 353 eyes of 215 subjects over 3 years, Dr. Stulting said. They concluded that the rate of loss was within an acceptable range.
In the Artisan study inclusion criteria, patients were required to have a minimum endothelial cell density of 2,000 cells/mm2. The average preoperative count was 2,754 cells/mm2.
Ophtec’s extrapolation showed a potential for a drop to 1,272 cells/mm2 over a span of 30 years.
On behalf of the FDA, Gerry W. Gray, PhD, a statistician for the Office of Surveillance and Biometrics, analyzed this data.
Dr. Gray said extrapolation of data to 30 years based on 3-year data was difficult. He noted that the loss of endothelial cells increased between the second and third years after implantation and that the rate of loss varied among patients. He estimated a rate of loss of 1.8% per year.
Approvable with conditions
The panel voted on a series of conditions regarding labeling for approval. Most of the conditions involved labeling changes to acknowledge potential lens-related complications and questions on the long-term results presented on the lens’ safety and efficacy.
The panel agreed that the minimum anterior chamber depth for Artisan candidates should be 3.2 mm and the power range should be no greater than 9 D of myopia. They also requested a post-market surveillance study.
The concerns over pupil size and endothelial cell loss were included in the labeling.
The panel also recommended listing trauma as a factor for lens dislocation; refining the definition of adverse events for patient education; including a mention that the potentials for development of glaucoma and of lens opacities are unknown.
The Artisan study
The U.S. Artisan study enrolled 684 patients, Dr. Stulting said. Of those, 478 were implanted bilaterally. The mean age was 39.6 years. Initially, the study was to span 2 years, but this was increased to 3 years to gather longer-term follow-up.
Dr. Stulting noted that the study group had high preoperative spherical errors, which put them at greater risk for complications. Mean preop refractive error was –12.3 D; the range was between 4.6 D and 21.9 D, he said. Mean lens power was –12.6 D, ranging from 5 D to 29 D, he said.
Dr. Stulting said 100% of eyes had a best corrected visual acuity (BCVA) of 20/40 or better at 2 and 3 years after the surgery. At 3 years, 49% of eyes had gained BCVA from preop levels, he said.
Postoperative adverse findings included flare, corneal edema, iris pigment precipitates on the lens, increased IOP and pupil ovalization. Dr. Stulting said ovalization with the Artisan lens is different from the progressive pupillary abnormality seen with angle-supported lenses. He said that these early postoperative findings decreased with time.
Secondary surgical interventions due to adverse events included lens explantation, lens exchange and repair of retinal detachment. He said many of these events are preventable through proper surgical technique. For this reason, comprehensive training of surgeons who wish to implant the Artisan is necessary, he said.
The amounts of visual aberrations, such as starbursts, halos or glare, were about the same preoperatively as postoperatively, Dr. Stulting said.
With commercial introduction of the lens, Dr. Stulting said, Ophtec believes postoperative results will be even better because the lens will be available in 0.5-D increments instead of the 1-D increments used in the trial.
For Your Information:
- Vance Thompson, MD, can be reached at Suite 140, 1200 South Euclid, Sioux Falls, SD 57105; phone/fax: 605-336-0266; e-mail: vthompson@ophthalmologyltd.com.
- R. Doyle Stulting, MD, PhD, director of Emory University Cornea and External Disease Section, can be reached at 1365 Clifton Road, Bldg. B, Atlanta, GA 30322; 404-778-4190; fax: 404-778- 5128.
- Jayne S. Weiss, MD, can be reached at the Kresge Eye Institute, 4717 St. Antoine, Detroit, MI 48201; fax: 313-577-5482; e-mail: jweiss@med.wayne.edu.
- William D. Mathers, MD, can be reached at the Casey Eye Institute OHSU, 3375 SW Terwilliger Blvd., Portland, OR 97201; 503-494-2745; fax: 503-494-3929; e-mail: mathersw@ohsu.edu.
- Gerry W. Gray, PhD, can be reached at the Center for Devices and Radiological Health, FDA/CDRH/OHIP/DSMICA, 1350 Piccard Drive, Rockville, MD 20850-4307; 301-827-3990 (consumer line); Web site: www.fda.gov/cdrh.
- Ophtec USA, makers of the Artisan/Verisyse phakic IOL, can be reached at 6421 Congress Ave., Suite 112, Boca Raton, FL 33487; 561-989-8767; fax: 561-989-9744; e-mail: ophtecusa@aol.com; Web site: ophtec.com.