The long-awaited SPRIT IV one-year results, presented at the recent Transcatheter Cardiovascular Therapeutics (TCT) conference in San Francicso, for Abbott’s Xience V drug-eluting stent (DES) over Boston Scientific’s Taxus DES found a stent thrombosis rate of 0.29 percent, which surprised even Chuck Simonton, Abbott’s chief medical officer.
Many observers expected similar results to SPIRIT III, which similarly compared Xience with Taxus Express in a randomized comparison, and found superiority with Xience in cardiac death, MI or repeat procedures (target lesion revascularization). However, in SPIRIT IV, which is the largest head-to-head DES trial to date, researchers found impressively low rates of stent thrombosis for both stents (1.06 percent for Taxus versus 0.29 percent for Xience).
“This year’s TCT represents the most positive moment [for drug-eluting stents] since the 2006 scare over stent thrombosis,” Simonton said.
While he acknowledged that the SPIRIT IV data does not extend past one year, Simonton pointed to SPIRIT III data, which extends out to three years.
“If SPIRIT IV replicates the findings of SPIRIT III, the stent thrombosis rates would be essentially flat, averaging about 1.5 percent per year, with no events in year three,” he said. The patients in SPIRIT IV are currently scheduled to be followed up to four years.
The one area of SPIRIT IV, in which Xience did not have statistical significant advantage over Taxus was amongst diabetics, where the target lesion failure rates were 6.4 percent (Xience) versus 6.9 percent (Taxus). Also, SPRIRIT was stratified, though not independently powered, to assess a diabetic cohort, with 1,185 diabetic patients.
“The stents performed pretty much the same in diabetics,” Simonton said. “Diabetes is a complex disease, and with the technologies available today—whether Xience or Taxus—these are more resistant lesions. As a result, we need new technologies, new drugs to make a real impact.”
Speaking of new technologies, Simonton also discussed Abbott’s pending takeover of the Evalve, a device developer for minimally invasive repair of cardiac mitral valves, which has received the CE Mark.
“As Abbott Vascular’s first venture into structural heart disease, it will provide a non-surgical means to fix a mitral valve that is leaking,” Simonton explained. He added that the results of the EVEREST, comparing Evalve’s percutaneous mitral repair using the MitraClip device to surgery, should probably be presented at the 2010 American College of Cardiology’s conference.
“We’re hoping that if the FDA accepts that data, we could be commercial by 2011,” he said. “This will be a whole new program for interventional cardiology, because previously, we haven’t been able to repair the mitral valve without open-heart surgery.”
However, he acknowledged that this new procedure will require training.
“At first, it may require interventionalists who have already been performing transseptal procedures for patent foramen ovale or atrial septal defects, and other left atrial procedures due to the specific skill set required,” Simonton said. “A good program requires an interventional cardiologist and a skilled echocardiographer, as the procedure is guided by transesophageal echocardiography.”