Dave Fornell, editor of DAIC Magazine
The Future of Stent Development Depends on Bigger Improvements in Outcomes
Stents were the key focus of interventional cardiology for more than 20 years, but the focus has changed in recent years in favor of novel, more sexy technologies in areas of structural heart repair, transcatheter valves, and new interventional therapies for hypertension, heart failure and stroke. I remember when the annual Transcatheter Cardiovascular Therapeutics (TCT) meeting was really focused on stent technology, partly driven by the stent wars between vendors 10 years ago who were competing to see who could build a better mouse trap and lower events rates with their next-generation devices. At recent meetings, the focus has seemed to be more on the novel interventional technologies, with transcatheter heart valve repair and replacement as the centerpiece.
I feel the reason for this refocusing in new areas is threefold. First, the stents and cardiac-related pharmaceuticals used today are very good and have cut the number of repeat customers returning to the cath lab. Second, there has been a proliferation of cath labs in the past 20 years, forcing competing hospitals to look for new ways to boost patient volumes. Third, the performance of the current generation of drug-eluting stents (DES) is outstanding and with comparable low event rates, which means the number of patients needed today to power a superiority study on late-term events rates would be vast and very expensive.
“To a large extent stents have been commoditized and it really boils down to prices today,” said Michael Mack, M.D., medical director, cardiovascular surgery, Baylor Health Care System and chairman of The Heart Hospital Baylor Plano Research Center. He and several other key opinion leaders shared their thoughts about new stent development during a press conference highlighting several new metallic and bioresorbable stent late-breaking trials at TCT 2016.
While there may still be a lot of stent R&D, the cost to run a superiority trial today against the Xience stent would be staggering. Mack said a new stent also would need to show much more than a small incremental increase for improved patient outcomes in order to justify the much higher cost of a new device. “The price point of these new stents may stifle future development of new devices,” Mack explained.
Today, unless a new stent can show significant patient outcomes improvement over the current generation devices, it is unlikely it will see wide adoption, said David J. Cohen, M.D., M.Sc., medical director of cardiovascular research at Saint Luke’s Mid America Heart Institute. This is especially true for devices that are more expensive than the current generation stents. He said if a device is only incrementally better, no one will pay twice as much for it.
At TCT last fall, there were a number of late-breaking trials that reminded me more of the TCT of years past, with a renewed focus on DES. This included advances such as polymer-free stents, drug-filled stents and bioresorbable polymer on metallic stents.
“We continue to see advancements in metallic stents, and metallic stents are not going out of the market,” stressed Roxana Mehran, M.D., professor of medicine, Icahn School of Medicine at Mount Sinai. She acknowledged bioresorbable stent technologies are exciting, but vendors are not about to give up on metallic stents and still have a lot of ongoing R&D investement.
It is true bioresorbable stents have renewed interest in stent technologies for many cardiologists, mainly because they offer a new concept that may have long-term advantages for patients. These devices have also had a lot of attention at cardiology meetings the past few years, and there was an explosion of interest in bioresorbable scaffold technology following the U.S. Food and Drug Administration clearance of the Absorb stent last summer. There are currently numerous bioresorbable stents approved in Europe, in development or entering trials.
“I think we are going to be overwhelmed with new bioresorbable scaffold trials,” Cohn predicted for future TCT meetings.
As a first-generation device, the Absorb has its faults, including its larger struts, lack of flexibility and three-year time to dissolve. “I think the race is on with smaller devices with faster absorption rates,” said Dean Kereiakas, M.D., medical director of The Christ Hospital Heart and Vascular Center, Cincinnati, Ohio.
The key for new device adoption includes the ability of the device to solve an ongoing clinical problem and significantly improve outcomes. Mehran said one area of stent innovation that really needs attention is devices that only require short-term dual-antiplatelet therapy (DAPT). “We are begging for a short-duration device,” she explained. “Three months is not really short for a patient who is at high-risk for bleeding.”