Boston Scientific failed to meet the primary endpoint of reduced stroke in the PROTECTED TAVR study. The Marlborough, MA-based company presented the results of the study, which evaluated the Sentinel Cerebral Protection system last weekend at the Transcatheter Cardiovascular Therapeutics (TCT) annual scientific symposium in Boston.

The device was designed to capture and remove embolic debris stemming from transcatheter aortic valve replacement (TAVR) before it can reach the brain and potentially cause a stroke.

Boston Scientific inherited Sentinel when it acquired Claret Medical in 2018 for about $220 million. This was around the time Boston Scientific was on an M&A spree.  

This randomized trial evaluated periprocedural stroke reduction and neurologic outcomes in patients with aortic stenosis treated with either the SENTINEL device to provide cerebral embolic protection (CEP) during TAVR or TAVR alone. 

The primary endpoint was not met, as the data demonstrated a non-significant trend toward a lower rate of stroke in patients treated with the SENTINEL device, representing a 21% relative risk reduction in all stroke through 72 hours or time of hospital discharge (2.3% with TAVR and CEP vs. 2.9% with TAVR only, P=0.30). 

“While this was a disappointment for investors and the interventional cardiology community alike, a secondary analysis did show a statistically significant 60% relative risk reduction in disabling stroke,” Marie Thibault, an analyst with BTIG wrote in analyst notes.

The secondary analysis showed a statistically significant 60% relative risk reduction in disabling stroke through 72 hours or time of hospital discharge in patients treated with the SENTINEL device (0.5% with TAVR and CEP vs. 1.3% with TAVR only, P=0.02).

Thibault wrote, “Following the data readout and in subsequent events, panelists and speakers debated the impact of the disabling stroke results. Some noted the findings shouldn't be ignored while others viewed it as a secondary endpoint in a negative trial. For now, we think the ambiguity of the trial isn’t likely to change clinical practice, with believers of the device continuing to use it, and those yet to adopt staying on the sidelines. When polled publicly, the physician panel discussing the results voted 7 to 1 to use Sentinel.”

She added, “Although PROTECTED TAVR missed its primary endpoint, we believe Boston Scientific can drive growth with multiple new products and expanding market opportunities.”