Five-year TAVR data reassure on durability

Five-year data from a clinical trial of early transcatheter aortic valve replacements showed good durability, allaying concerns raised by a study last month in which more than a third of the valves deteriorated significantly over that span.

Results from the Partner clinical trial, presented last week at the Transcatheter Valve Therapies conference in Chicago, showed a much lower mean gradient (the change in pressure across the valve) than were found in a smaller study presented in May at the annual EuroPCR meeting in Paris. The researchers behind that study predicted that as many as half of all 1st-generation TAVR devices, like the Edwards Lifesciences (NYSE:EW) Sapien valve, would show signs of deterioration within 8 years.

But 5-year data from the Partner I trial of the 1st-generation Sapien showed that the mean gradient was both in-line with its surgical device replacement comparator and well below the threshold set by the earlier trial. Sapien patients in Partner I showed mean gradients of 10.7mmHG, compared with 10.6mmHg for the surgical arm and about half of the 20mmHG or more mark set by lead author Dr. Danny Dvir, of Vancouver’s St. Paul’s Hospital.

The 5-year Partner I data show “valve durability as evidenced by stable valve areas and gradients out to 5 years,” Columbia University’s Dr. Rebecca Hahn said in presenting the findings at TVT last week. Further study of late valve deterioration and early valve thrombosis – an issue that prompted a warning from the FDA last fall – need more study, including observational and computational modeling, Hahn said.

Further corroboration on the durability issue came from a real-world study of TAVR implantations at a center in Rouen, France, that showed only 1 case of severe valve deterioration, defined as a mean gradientof 40mmHg or higher, and 4 cases when the SVD bar was set at 20mmHG or greater.

The Rouen study also showed a lower mortality rate at 5 years than either the high-risk Partner A cohort or the Partner B inoperable cohort, at 28.0% compared with 32.2% for Partner A and 28.2% for Partner B.

Leerink Partners analyst Danielle Antalffy said physicians she interviewed at TVT, a pair of high-volume TAVR users, discounted the EuroPCR data because the study was too small and not core lab adjudicated. One surgeon told Antalffy that TAVR devices will likely last 10 to 12 years before deteriorating, compared with about 15 years for surgical valves.

“But even then, these physicians believe that durability is likely to remain in focus longer-term and analyzed carefully via CT (computed tomography) and echocardiography in a low-risk trial (Partner 3 [of Edwards’ Sapien 3 valve]) and as we move into intermediate patients (approval expected soon),” she wrote in a June 20 note to investors. “With respect to detecting a signal for deterioration of the valve, these physicians believe that lack of any signal at 5 years is suggestive of the fact that TAVR is unlikely to deteriorate in the 7-8 year timeframe as was suggested at EuroPCR.”

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