WASHINGTON — Six months after the Institute of Medicine (IoM) issued a report recommending the dissolution of FDA’s 510(k) medical device approval process, the agency has yet to release their official response — a delay that has legislators concerned.

Unofficially, agency officials have said that, while they respect the IoM’s work, they have no intention of doing away with 510(k) — the FDA’s program for providing expedited approval to moderate-risk Class II medical devices by proving “substantial equivalence” with devices already on the market.

IoM contended that the process cannot assure that devices are safe or effective and that many of the old devices used for comparison have been on the market since before laws began requiring medical device evaluation. FDA officials have argued it is better to improve the existing program than do away with it when there is no alternative to take its place.

Regardless of which is the better path to take, legislators are looking for action in one direction or the other.

Making Poor Comparisons

“There’s no virtue in getting devices to patients quickly if they don’t work or if they cause injury or death. I think most Americans would be alarmed if they understood the process we use now to approve devices,” said Sen. Tom Harkin (D-IA) at a recent Senate Health, Labor and Pensions Committee hearing. “They would think that for any high-risk device — anything that’s implantable in the human body — that experts at FDA would examine clinical data and conclude that the device is demonstrated to be safe and effective. But that’s not what happens. Most devices are cleared through a process by which devices are shown to be ‘substantially equivalent’ to another device that’s already on the market, even if that device was substantially equivalent to a previous device, and that previous device was substantially equivalent to a previous device, and on and on and on.”

Harkin used the circumstances surrounding the approval of “metal on metal” artificial hip implants — implants that use metal ball and socket joints. In recent years, physicians have found that, as the devices wear down, they can release metal shavings into the surrounding tissue, causing inflammation and permanent damage. The metal implants also have been associated with a high accumulation of metal ions in patients’ tissues and bloodstreams.

A study released last month by researchers at the Patient-Centered Comparative Effectiveness Program at Weill Cornell Medical College in New York found that the metal implants fare no better than the older metal-on-polyethylene or ceramic-on-polyethylene implants. However, there is evidence of higher rates of replacement surgery associated with the metal-on-metal implants.