Medical Device Daily Washington Editor

Given current demographics and the amount of back problems we are having, the market for artificial spinal disc appears large — on paper up to $1 billion yearly and growing — but problems with existing disc replacement technology and uncertainties concerning reimbursement leave manufacturers with a difficult job of predicting uptake or the true market potential. However, device makers are nothing if not optimists and recent developments in this space indicate that this market sector is real, and likely to grow.

Medtronic (Minneapolis) on Tuesday won a unanimous nod of recommendation for approval from the FDA's orthopedic and rehabilitation devices panel for its Prestige cervical disc system.

Previously approved artificial discs, the Charit from Johnson & Johnson (New Brunswick, New Jersey) (Medical Device Daily, Oct. 28, 2004) — the first such product approved in 2004 — and the ProDisc from Synthes (Westchester, Pennsylvania) approved last month (MDD, Aug. 18, 2006), are for use in the lumbar spine. In contrast, the application of the Prestige is for the cervical spine. And similar products in development promise to crowd the field substantially for both uses in the coming months and years.

The panel gave its nod to the Prestige with conditions, however.

One of these was a requirement for post-marketing surveillance, not an uncommon condition of approval.

The company will also be prohibited from claiming that the Prestige is superior to spinal fusion if the agency accepts the panel's guidance, a recommendation that the claim be limited to “non-inferiority.” The panel also recommended that the FDA limit Medtronic's use of clinical motion discussions in marketing literature and require more analysis of pre-clinical toxicity.

Still another condition of the panel's recommendation is that the agency require that the indication be narrowed down to cervical degenerative disc disease that involves “intractable radiculopathy and/or myelopathy with symptomatic nerve root and/or spinal cord compression,” as confirmed by radiological studies.

More than 200,000 patients in the U.S. opt for spinal fusion for cervical disc problems each year, making the market for this and future competitive devices potentially lucrative. At an anticipated price of $4,500 per surgical set for the Prestige vs. that of the surgical set for standard spinal fusion (said to run between $3,000 and $3,500), Medtronic will have to make a strong argument for its product in order to foster a healthy sales volume.

The Prudential Equity Group (New York) commented that this price gap would “be difficult to justify with CMS and private payers,” especially so for CMS since “the average age in [Medtronic's] clinical trial was 43.”

Nonetheless, the Prudential report also said that Medtronic's sales volume could top $400 million for the Prestige in fiscal year 2011.

While Medtronic will have to overcome problems with reimbursement and pricing in order to ramp up sales of the Prestige, the fact that the company currently holds the cervical disc replacement market to itself gives it the luxury of putting the device into play slowly and weeding out problems as it goes.

Another issue Medtronic and others in the sector must grapple with is the negative publicity attaching to the Charit , made by J&J orthopedic business Depuy Spine (Raynham, Massachusetts). The Charit is the subject of roughly 130 serious adverse events reported to the FDA by patients, including those for disc migration and damage to nearby blood vessels (MDD, August 3, 2006).

The device has been in use in Europe since 1989, but there are few studies of the device spanning more than two to three years.

And several lawsuits have made their way into court over the Charit , and the New Jersey law firm of Bagolie Friedman (Jersey City) has reported the formation of a practice group dedicated entirely to these patient lawsuits.

One of the firm's partners, Ricky Bagolie, said that J&J “is responsible for manufacturing a medical device they knew or should have known was unreasonably dangerous in an attempt to capture some of the lucrative multi billion dollar back surgery market.” He promised to pursue cases in Europe and Australia as well as the U.S.

Since the ProDisc from Synthes has been on the market only since August, there has been little time to attract post-marketing problems – or potential litigation.

CMS agreed to reimburse for the Charit in May, after an earlier refusal to do so, but the coverage is limited to patients aged 60 and younger, severely limiting the sales potential of the device.

CMS payment for the Charit also hinges on approval by a local medical director, relieving the agency of the necessity of rendering a national coverage decision. By some accounts, much of the feedback to the agency on the initial non-coverage decision emphasized the impact of that decision on private payers, which could consequently suppress funding for further development of such products.

Robin Young, a medical device industry analyst in Wayne, Pennsylvania, commented that “there is almost unanimous opinion that arthroplasty will fare better in cervical areas” than in the lumbar region in part because the procedure is less hazardous than lumbar spinal surgery, partly because many surgeons are more familiar with the cervical spine.

However, Medtronic's data for animal studies indicated that small amounts of stainless steel could come off the disc over time, and the company apparently was unable to determine the fate of the stainless steel particles.

One of the members of the FDA's advisory panel, Dr. Sanjiv Naidu, a professor at Pennsylvania State College of Medicine (Hershey), said that he was “a bit dumbfounded why the particles were not found anywhere.”

Another complication confronted by the panel was that Medtronic has made changes in the product, those changes not found in the disc used in the clinical trial. The changes included altered screw positioning and thickening of one portion of the disc, allowing a larger architecture.

Medtronic reports that it is currently pursuing trials examining two different versions of the disc.

Medtronic is projecting agency approval of the disc in the first half of next year.

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