Merit Medical’s Wrapsody Endoprosthesis Meets Endpoints of FIH Study

September 20, 2021—Merit Medical Systems, Inc. announced positive results from a prospective, observational, first-in-human (FIH) study to evaluate the safety and effectiveness of the company’s Wrapsody endoprosthesis. Wrapsody is a self-expanding, cell-impermeable endoprosthesis designed for the treatment of arteriovenous (AV) fistula access circuit stenosis and AV graft access circuit stenosis.

James A. Gilbert, BMBS, et al, published the findings online in CardioVascular and Interventional Radiology. Dr. Gilbert, who is the study’s primary investigator, is Consultant and Transplant & Vascular Access Surgeon, Vascular Access Lead, at Oxford University Hospitals NHS Foundation Trust in Oxford, United Kingdom.

According to the company, the WRAPSODY FIRST study enrolled 46 patients with clinically relevant stenosis, who were treated at three centers. The eligible population consisted of patients undergoing hemodialysis through an AV circuit with clinical and radiological evidence of stenosis at the graft-vein anastomosis, in the peripheral outflow veins or in the central veins up to the superior vena cava. The patients in the study did not have clinically relevant secondary stenosis or thrombus in the access circuit.

The study reported anatomical, clinical, and procedural success in all cases. The primary safety outcome measure was the proportion of patients without localized or systemic safety events affecting the access circuit that resulted in surgery, hospitalization, or death during the first 30 days after device placement. All but one patient was free from such a safety event in the first 30 days after device placement (97.8%). The safety event was adjudicated as not related to the device or study procedure. During the remainder of the study, there was one adverse event adjudicated as possibly device related.

The primary effectiveness outcome for the study was target lesion primary patency (TLPP) rate at 30 days after device placement. The investigators found that TLPP was 100% at 30 days, 97.7% at 6 months, and 84.6% at 12 months. The access circuit primary patency rate was 84.4% at 6 months and 65.9% at 12 months.

The investigators noted that TLPP rates were similar regardless of access type and lesion location or whether patients were treated with a single device or overlapping devices. In all cases, reintervention at the target lesion was successful in maintaining patency; 12-month assisted TLPP rate of 100%.

“Early FIH study results show that the Merit Wrapsody endoprosthesis can be safely used to treat stenoses at key sites within a dialysis access circuit,” commented Dr. Gilbert in Merit’s press release. “Even more encouraging are the very promising primary 1-year target lesion patency rates of 84.6% and access circuit patency rate of 65.9%. To my knowledge, these are higher than any other published data and suggest that the novel features of the Wrapsody endoprosthesis may have a key role in preserving the longevity of precious dialysis access for our patients.”

The company advised that it is also conducting the large multinational, multicenter Wrapsody AV Access Efficacy (WAVE) study, which will be used to support a premarket approval application to the FDA.

The randomized WAVE study is comparing the Merit Wrapsody endoprosthesis to percutaneous transluminal angioplasty for treatment of venous outflow circuit stenosis or occlusion in hemodialysis patients. The beginning of enrollment was announced in March 2021. The study is anticipated to include 477 patients, stated Merit Medical.