Even before the committee voted, it was not looking good for Intrinsic and its annular closure device for discectomy patients, Barricaid.
Then the committee voted, and by a margin of 9 to 5, the committee said that there was insufficient evidence of Intrinsic’s annular closure device’s safety when implanted to prevent disc re-herniation.
It did vote 12-1 that Barricaid was effective at preventing reherniations following discectomy.
When asked, however, whether the benefits outweighed its risks, the committee said “no” by a vote of 8 to 5.
The vote by the FDA’s Orthopaedic and Rehabilitation Devices Panel of the Medical Devices Advisory Committee occurred on December 12, 2017.
Did the Panel Miss the Forest for the Trees?
There is one big problem with the Panel’s decision. The efficacy measure in this study included, in fact, safety observations such as reductions in adverse events and re-operations.
The full data from the study showed that using Barricaid cut recurrent disc herniations 56%, reduced re-operations 49% and, finally, lowered serious adverse events 33%.
So, what were the safety concerns that caused the panel to vote “no”?
Barricaid’s RCT Study
Barricaid’s study, which was a prospective, randomized investigation, recruited 554 discectomy patients of which 276 were randomized to Barricaid after a discectomy while the remaining 278 received discectomy alone. This is the largest ever conducted for an annular closure device with 24-month endpoints that included re-herniation and a composite of safety and effectiveness.
This type of composite score is the acid test for any device and all previous premarket approval (PMA) spine studies have included five or six composite components. In this trial, the bar was elevated to eight components, all of which had to be successful to demonstrate statistical superiority. Barricaid did that. Superiority.
Patients were followed for a minimum of twp years post-op with a significant number going out as far as five years—again, a record follow up for review by a PMA spine device Panel.
The FDA noted in their instructions to the panel, that CT imaging showed bone changes to the vertebral endplates for some of the Barricaid patients.
Endplate Changes
Endplate changes are a well-known observation following discectomy, and are not generally associated with clinical symptoms.
Eighty-eight percent of the patients receiving Barricaid had endplate changes versus 40% of control patients. The control patient’s changes were smaller on average and appeared to stabilize sooner than the Barricaid patient’s. The Barricaid endplate changes were larger and had a distinctive radiographic feature—according to the FDA’s radiologist. What those distinct features were, however, remain unclear.
Intrinsic carefully analyzed these endplate changes and found no correlation to measured study outcomes, pain or function.
