W.L. Gore & Associates researchers defended St. Jude Medical’s (NYSE:STJ) failed patent foramen closure device study, arguing that, although the study failed to meet its clinical endpoints it highlighted the need for better patient inclusion criteria.
St. Jude last month lost some Wall Street love after it unveiled the results of its RESPECT trials, which showed that the company’s Amplatzer heart implant failed to significantly reduce cryptogenic stroke compared with standard treatment with drugs.
"The response to these findings has, thus far, been mixed," Gore researchers wrote in a prepared response. " Those in favor of PFO closure have emphasized that these findings, together with the secondary endpoint analyses, reaffirm that carefully selected patients with a history of cryptogenic stroke and PFO may, indeed, benefit in stroke risk reduction from device closure over medical management alone."
"Others, however, are quick to point out that this evidence is inconclusive given the lack of statistically significant primary endpoint results demonstrating superiority of one therapy over another," they added.
The news dragged STJ shares down 4% in one day as the company attempted to highlight the positive elements of the study results.
St. Jude also pointed out that the data may have been skewed by a quirk in the study’s design that meant that 3 of the 9 patients in the study who never received the implant were included in the Amplatzer arm. Excluding those patients, and patients in the drug treatment cohort who dropped drug therapy, and the risk of stroke was 63% lower for patients treated with the Amplatzer device.
The device was designed to treat a condition called patent foramen ovale, in which a naturally-occurring hole in the heart fails to close after birth, potentially allowing blood clots to travel from 1 side of the hart to the other and then to the brain, causing a stroke.
St. Jude compared its Amplatzer against drug therapy in patients with recurrent cryptogenic stroke and PFO, reporting a non-statistically significant reduction of 50.8% in its primary endpoint when compared with drug therapy alone.
Gore sided with the study, emphasizing that well-defined inclusion and exclusion criteria are "imperative" to producing success in PFO device closure studies, but also highlighted areas of the Gore study that were different from St. Jude’s, including in prescription of anti-platelet therapy, follow-up protocols and neuroimaging schedules. .
Gore is currently in the midst of a clinical study evaluating its Gore and Helex septal occluders in treatment of PFO. Gore hopes to demonstrate that patients treated with its PFO closure devices along with anti-platelet medication have reduced rates of recurrent stroke or transient ischemic attacks when compared with patients taking the drug regimen alone.
The FDA has not yet approved any septal occluders for treatment of patent foramen ovale closure, but the Gore device has had CE Mark approval for use in the European Union since June 2011. The Amplatzer device has been on the European market since 2008.
Once-rival NMT Medical ran aground after a clinical trial of its StarFlex implant for treating PFO failed to show that it could prevent recurrent stroke and transient ischemic attack. W.L. Gore later bought bankrupt NMT’s assets at auction.
St. Paul-based St. Jude bought its Amplatzer technology, along with AGA Medical, for $1.03 billion in 2010.