The final results of the ENDURE study, investigating the efficacy of the Chocolate Touch drug-coated balloon (QT Vascular), show “promising evidence of the drug effect by way of low late lumen loss and high patency at 12 months,” according to Gunnar Tepe (Institute of Diagnostic and Interventional Radiology, Frankfurt, Germany) who presented the findings at the 2017 VEITHsymposium (14–18 November, New York, USA). Tepe reported a six-month patency of 88.9% (n=48/54) and a twelve-month patency of 83.6% (n=46/55).
“The combination of the Chocolate platform and the paclitaxel coating offers the potential to avoid stents almost entirely,” Tepe said, explaining that the drug-coated balloon “achieved low residual diameter stenosis, similar to stents, and no flow-limiting dissections, resulting in an extremely low rate of per protocol bail-out stenting.”
Tepe told VEITHsymposium delegates that the acute arterial trauma produced by conventional balloons constitutes a “key unmet challenge”. The Chocolate balloon uses “constrained expansion” to reduce such trauma, employing nitinol struts around the expanding balloon and reduce the stress to the vessel wall. When a paclitaxel coating is added to the balloon, the combination forms the Chocolate Touch drug-coated balloon, which Tepe said has a 20% larger drug-coated surface compared with conventional balloons. He also noted that this is a one-step device, and does not require pre-dilatation.
The single-arm ENDURE feasibility study of the drug-coated balloon was conducted at four sites in Germany and New Zealand. Sixty-seven patients (70 lesions) were enrolled, all of whom had single or tandem de novo lesions ≤150mm in length, target reference vessel diameter 4.5–6mm in diameter, and of Rutherford grade 3–5. Above-then-knee follow-up was conducted with duplex ultrasound at 30 days, six months (plus a Quantitative Vascular Analysis [QVA]) and 12 months. Below-the-knee follow-up was conducted with duplex ultrasound at 30 days, three months (plus a Quantitative Vascular Analysis [QVA]), six months and 12 months.
Tepe noted that the ENDURE had a more complex Rutherford grade population than other drug-coated balloon studies, with 93% grade 3, 3% grade 4 and 4% grade 5. The mean ankle brachial index was 0.7. Investigational device exemption studies for the Lutonix (Bard/BD) and IN.PACT Admiral (Medtronic) excluded Rutherford grade 5 categories, and included grade 2 patients—29.5% and 37.7%, respectively. Also notable were the rates of severe calcification (22.9%) and total occlusion (33.3%) in this patient cohort.
Tepe told delegates that the study results confirmed high rates of procedural and device success with low rates of dissection (1.4%) and bail-out stenting (1.4%). Compared with pre-treatment, patients treated with Chocolate Touch demonstrated material improvement in ankle brachial index at 30 days (+0.28), six months (+0.26) and 12 months (+0.29). Reductions in Rutherford grade were also observed at 30 days (average -2.7), six months (average -2.5) and 12 months (average -2.6).
At six months, there were four total major adverse events, all of which were clinically-driven target lesion revascularisations. At 12 months, there were four clinically-driven target lesion revascularisations and one case of all-cause death.
Tepe concluded that the low late lumen loss and high 12-month patency demonstrated were “promising”. He also suggested that the device’s constraining structure “may have a protective effect on the paclitaxel used.” Tepe also noted that this potential would be evaluated in an upcoming investigational device exemption study. This study will enrol up to 500 patients at 50 sites in the USA and Europe and will follow them out to five years.