Stryker’s Wingspan: A Regulatory Conundrum For FDA?

In short

Stryker’s brain stent has been used in USA since 2005 on a Humanitarian Device Exemption (HDE) basis and now faces FDA expert panel review on its tortuous route to full market clearance.

Background

The system, called Wingspan and originally Boston Scientific’s before the purchase by Stryker if its neurovascular business in 2010, has been massively contentious as results of its implantation in what was seen as a pivotal study were worse than those for non stented patients. In fact stroke and death rates at 1 year were 20% and 12.2% respectively, resulting in the 764 patient study being halted after 451 patients. Far from suggesting this was because of device failure, the Data Safety Monitoring Board had judged there to be enough evidence for a conclusive finding at this stage.

“Reckless disregard for public safety” or bump in the road en route to approval?

As usual there are two sides to every story, so while the strident voices of patient safety lobbyists across the land question the continued presence of the device on the market (albeit still under HDE rules), Stryker themselves and indeed some of the researchers involved in the study adopt a stout defence of the technology, likening the device to the early days of coronary stenting when again the results were poor, only for the technique to be routine now. Furthermore, while investigators at the Cedars Sinai site admit the results are disappointing they also point out that the procedure is clearly effective for some patients and indeed are concerned that patients who “might benefit from minimally invasive placement of a mesh tube or stent to open blocked brain arteries may be discouraged by this report.”

The full Cedars Sinai press release from late last year can be found here.

Perhaps most damning or worrying for Stryker is the fact that a former FDA surveillance officer and CDRH director, Dr Larry Kessler has written a strongly worded letter in support of a petition by the Public Citizen organisation calling for the immediate withdrawal of the device’s HDE approval. Public Citizen called the continued HDE approval of the device a “reckless disregard for public safety”. In his letter, Dr Kessler states he “can see no reason why this device should continue to be available.”

What does this tell us about assessment of device safety and efficacy?

Well it certainly provokes and informs the debate doesn’t it? With more legalists covering the story on their websites than one could shake a stick at, there’s no doubt a rocky road ahead for Stryker on this one, but the fact of the matter is that if the device works it will be a success.

End of story? Not quite. It’s a fair prediction that the device, if approved, will be restricted to those patients in whom the clinical data suggests it is safe and effective. This doesn’t sound like it means everyone, and may mean only the sickest patients, leaving open the question of the patients and relatives for whom it was unsuccessful in the study and on whom it continues to be used. Yet again though, what could be another one of those metal-on-metal hip, externalising defibrillator type disasters could also be a lifesaver. Damned if you do, damned if you don’t.

Of course in Europe the device is approved and in use, raising once again “the question” about whether EU approval is too easy, US too strict or the other conclusion which is that clinical trials don’t always help if the results are open to interpretation as they almost always are.

Source:  Massdevice, medlatest staff