A pivotal clinical trial of Tryton Medical‘s side-branch stent, the largest ever conducted on coronary bifurcation lesions, failed to meet its primary endpoint for target vessel failure.
Results from the 704-patient, randomized study, published this month in the Journal of the American College of Cardiology, showed that at 9 months TVF was 17.4% in the cohort treated with the Tryton device, compared with 12.8% for the control group treated with a provisional stent and balloon angioplasty (p = 0.11).
The researchers put the discrepancy down in part to a higher rate of periprocedural myocardial infarction in the Tryton group (13.6% vs. 10.1%, p = 0.19).
"Provisional stenting should remain the preferred strategy for treatment of non–left main true coronary bifurcation lesions," the researchers wrote.
For its part, Durham, N.C.-based Tryton noted that some 60% of the study’s subjects had side-branch vessels smaller than 2.25mm, which was the cutoff for the intended patient population. A post-hoc analysis of that intended population found 289 patients with reductions in TVF and side-branch percent diameter stenosis with the Tryton stent, the company said.
Both treatments showed similarly low rates of stent thrombosis and no cardiac deaths at 9 months, Tryton said.
"As we reported in October 2014, analysis of the findings from the Pivotal IDE trial for Tryton side branch stent indicates significant benefit in the intended treatment population. Based on these important findings, Tryton has initiated The Tryton Extended Access Registry, a single-arm study of the Tryton side branch stent designed to confirm results from the Pivotal IDE trial in the intended treatment population of patients with lesions involving significant side bifurcation," president & CEO Shawn McCarthy said in prepared remarks. "We remain on schedule to complete enrollment and file our pre-market approval application with the FDA this year."
"The Tryton IDE study is a landmark clinical trial representing the coordinated efforts of leading investigators in the U.S. and Europe," added lead author Dr. Philippe Genereux of the Core Angiographic Laboratories at the Cardiovascular Research Foundation. "The most important finding was the performance of the Tryton stent in the intended population presenting with complex bifurcations involving significant side branches. In this population, Tryton showed a reduction of TVF within the non-inferiority margin pre-specified for the entire population and significantly reduced side branch percent diameter stenosis."
Last September Tryton said it made an initial closing on a $20 million equity round for the IDE trial. Tryton in May 2013 won CE Mark approval in the European Union for its eponymous stent in large vessels (a CE Mark indication for left main coronary artery disease followed in February 2014).