Medtronic parked its tanks squarely on Edwards Lifesciences' lawn yesterday by CE marking its Engager transcatheter aortic valve. Unlike CoreValve, the other transcatheter valve Medtronic sells in Europe, the device is delivered transapically. Medtronic will now be able to contest the 20% of the market over which Edwards has hitherto held sway.
Elsewhere in Medtronic's transcatheter aortic valve implantation (TAVI) franchise, though, trouble may be brewing: the FDA has warned that informed consent had not been properly obtained from some of the participants in CoreValve's pivotal US trial. Medtronic says that the issues are "site-specific" and will not affect the overall study but, with the European market increasingly crowded, US approval of CoreValve is crucial - anything that could delay it is bad news indeed.
From the bottom of my heart
Engager is approved for the treatment of patients with severe aortic stenosis who would be at high or extreme risk of death if they were to undergo valve replacement surgery. It is implanted using a catheter inserted in the bottom of the heart - its apex. Transapical delivery involves punching through the cardiac muscle, and tends to be used when the less traumatic transfemoral delivery route is unsuitable.
Edwards' devices, Sapien and Sapien XT, may be delivered transapically and transfemorally. Medtronic has a transfemoral device already on the market in CoreValve, and CoreValve may also be delivered by the less common subclavian and direct aortic routes (Therapeutic focus - Transcatheter aortic valves boosted by guidelines, October 1, 2012). CE mark of Engager means that one of Medtronic's valves can be delivered by all four routes, compared with Edwards' two.
Delay to US approval?
The focus now switches to the US, where Medtronic is seeking to break Edwards' monopoly by obtaining approval for CoreValve by the end of next year. The FDA's warning letter to Dr Michael Ring, a researcher at Providence Sacred Heart Medical Center in Spokane, Washington, has thrown a spanner in the works.
The agency pointed to two cases where patients underwent CT angiography without having first signed an informed consent document; a further three patients were randomised into the clinical trial and only later gave written consent.
Furthermore, Dr Ring allegedly failed to report significant clinical events - including a case where one patient who had to have bypass surgery, another of surgical aortic valve replacement, and two patient deaths - within five days. Record-keeping was also inadequate.
Implantations of CoreValve at the Spokane site have been stopped, and will not restart until the FDA's concerns are allayed.
The pivotal study is due to report in the second half of 2013, and this deadline must be met if Medtronic is to get CoreValve approved before 2015. With new devices entering Europe all the time, pushing down both Medtronic's and Edwards' share, the grudge match will be played out in the US.