WASHINGTON -- The U.S. Food and Drug Administration said it should not have approved a collagen-based knee implant called Menaflex under the 510(k) process and will seek to revoke the product's clearance after meeting with its manufacturer.
The product, cleared by the FDA's Center for Devices and Radiological Health in December 2008, came under fire a few months later when the FDA -- then under new leadership -- announced an internal investigation into the approval process for Menaflex. A parallel inquiry began in Congress at the same time.
The FDA has now concluded that the 510(k) process was inappropriate in this case because Menaflex "is intended to be used for different purposes and is technologically dissimilar from devices already on the market."
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It also cited findings from its internal investigation suggesting that "external pressures" had influenced the device's review.
Menaflex is a crescent-shaped piece of resorbable collagen-based material that is surgically implanted in the knee joint following removal of damaged meniscal cartilage. It was approved for patients with medial meniscus injuries.
According to its manufacturer, ReGen Biologics of Hackensack, N.J., the product is intended to provide a scaffold for new meniscal tissue to grow.
The FDA said this is different from other approved knee implants then on the market, which merely provided replacement or support for damaged tissue.
"Instead of simply repairing or reinforcing damaged tissue like predicate devices, Menaflex is intended to stimulate the growth of new tissue to replace tissue that was surgically removed. Because of these differences, the Menaflex device should not have been cleared by the agency," according to the FDA.
Before beginning the revocation process, the FDA indicated, it would seek a meeting with ReGen officials to discuss the appropriate marketing pathway for the device and what data it would need to provide a reasonable assurance of safety and effectiveness.
The company could theoretically get the product cleared again by going through the premarket approval (PMA) process, which is more stringent than the 510(k) pathway.
The latter process requires only that a product sponsor demonstrate that its device is "substantially equivalent" to one or more products already cleared for marketing. First-in-class products require a PMA, for which full efficacy and safety trials must be conducted.
ReGen issued a statement indicating that "the company is currently weighing its options." It also asserted that "there has never been a safety issue" with the product.
In justifying its decision to yank Menaflex's 510(k) clearance, the FDA cited findings from its internal investigation that were released in September 2009, indicating that "external pressures" had affected the product's review.
The investigators found evidence that ReGen had lobbied the FDA's commissioner in 2008, Dr. Andrew von Eschenbach, on behalf of Menaflex, such that he became "personally engaged in the details of a process usually coordinated at the Center level."
According to their report, von Eschenbach ordered the CDRH's director at the time, Dr. Daniel Schultz, to convene a review panel meeting for Menaflex on short notice, the result being that several experienced members could not attend and materials were made available one week before the meeting instead of the usual three to five weeks.
The report also noted that the commissioner showed "unusual interest in the composition of the panel," asking to see their resumes, and "pressed the Center to issue a decision" shortly after the panel's November meeting, as did the company.
The center's staff had initially determined that Menaflex was not substantially equivalent to existing approved devices and hence ineligible for 510(k) approval. But Schultz ordered a reconsideration of that determination, which was subsequently reversed.
Under pressure from ReGen, staff who had participated in the original negative review were not allowed to speak at the panel meeting, the investigation found.
The report also indicated that Schultz allowed the final clearance to include approval for acute as well as chronic meniscal injuries in accordance with documents submitted by the company, even though it had previously agreed to limit the requested indication to chronic injuries only.
Schultz resigned in August 2009 following allegations from some CDRH professional staff that they had been pressured by senior officials to reverse negative device evaluations.
In deciding to revoke Menaflex's clearance, the FDA also relied on input from its Orthopedic Devices Advisory Committee, which met this past March to review the scientific data on the product.
The panel expressed few concerns about the product's safety, but indicated that the evidence for its effectiveness fell short in some areas.