FDA advisory panel to vote on whether to recommend approval of Medtronic's spinal implant

The Diam Spinal Stabilization System--Courtesy of Medtronic

The FDA is convening its experts on the Orthopaedic and Rehabilitation Devices Panel on Feb. 19 to recommend whether to approve Medtronic's Diam Spinal Stabilization System. The FDA is not obligated to follow the advice of its advisory panels, although it typically does.

The Diam's proposed patient population is patients with moderate low back pain secondary to single-level symptomatic lumbar degenerative disc disease, according to the meeting documents. "It was designed to treat patients that have not progressed down the degenerative disc disease continuum sufficiently to warrant more complex invasive procedure such as a disc replacement or fusion," Medtronic said in its executive summary.

The panel of experts will be asked to comment on the device's clinical trial, which included 150 subjects with a variety of disc displacement abnormalities.

The FDA takes issue with the heterogeneity of the patient population. "Consequently, data related to subjects with these different spinal pathologies may not be poolable, and the Agency does not agree with the sponsor's conclusion that the results are poolable based upon a post hoc analysis showing comparable treatment effects in each identified subgroup," the FDA executive summary says.

Medtronic says that using the Oswestry Disability Index, the device had a success rate of 69.1% compared to 17% among the 50-person control group, who received nonoperative treatment, such as medications or physical therapy. In addition, the Diam was found comparable in safety to the control treatments, Medtronic said.

But the FDA writes that "in the context of the proposed target population, as well as the Agency concerns pertaining to the study population and nonoperative control group, it is unclear if the definition of the primary effectiveness endpoint and the assessment of overall success at 12 months are adequate."

The panel's opinion will therefore be critical toward informing the FDA's decision to reject or approve the Diam. They will be asked to comment on various aspects of the trial, including its patient population, the adequacy of the control group and primary endpoint, whether the device should be a primary or adjunctive therapy (meaning it may be indicated for use with direct spinal decompression), the radiographic outcomes and a postmarket study that would be conducted if the device is approved.

At the end, the panel will vote on whether the device offers a reasonable assurance of efficacy and safety, and most importantly, whether its benefits outweigh its risks.

The Diam is already sold in countries throughout the world, including Argentina, Canada, Denmark, India, Kazakhstan, Malaysia, Romania, South Africa, Thailand and Venezuela.

- read the meeting literature
- more about the clinical trial

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