UNITY-B A Prospective, Multicentric, Single-arm Study to Evaluate the Safety and Efficacy of the UNITY-B Biodegradable Balloon-Expandable Biliary Stent System in Subjects With Biliary Strictures

RATIONALE (STUDY PURPOSE) Recent publications report the experience with temporary placement of self-expanding metallic stents (SEMS) in benign biliary strictures, which could offer several advantages over conventional plastic biliary stents. Removability can be complicated when there is tissue ingrowth through uncovered portions of the biliary SEMS.

Use of a biodegradable stent would eliminate procedural risk and expense associated with stent removal. In addition, a stent made of highly biocompatible material may be less prone to induce hyperproliferative damage to the ductal system than would plastic or metal stents. For biliary applications, biodegradable stents have been evaluated in several in-vitro and animal studies that proved the stents for being safe and well tolerated. They provided an adequate radial force and resulted in complete stricture resolution within several months. The stents did not show any signs of biliary hyperplasia or integration in the epithelium. Moreover, they seem to have a self-clearing effect on attached biofilm as the outer layer sloughs during the degradation process similarly to the exfoliation of human skin. Also, the stent could be removed from the bile duct, thus offering the possibility of extraction if necessary, at various times after implant.

Therefore, the aim of this clinical study is to evaluate the safety and the efficacy of the UNITY-B Biodegradable Balloon Expandable Biliary Stent System for draining obstructed biliary ducts to improve bile flow in patients suffering under biliary strictures accompanied by jaundice and pruritus or to maintain good clinical status for patients already drained by PTBD or primary stenting.

STUDY DEVICE The UNITY Balloon-expandable Biodegradable Biliary Stent System is comprised of two main components: a balloon-expandable, biodegradable hybrid stent and an over-the-wire balloon catheter delivery system. The UNITY-B System provides a means of safely advancing the stent to the desired location within the common bile duct and, once in position, the stent is deployed by inflating the balloon. The balloon expands to the nominal diameter under nominal pressure. The process in which the UNITY- B stent degrades is through hydrolysis. Implantation is endoscopally guided (ERCP) and stent advancement and deployment by virtue of a guide wire and balloon catheter. In cases of altered anatomy this device can be used for percutaneous transhepatic access as well.

POPULATION Patients with biliary strictures and suffer under jaundice associated with tea color urine, pale stool and pruritus. Biliary drainage relieves both and improves related symptoms like anorexia, diarrhea, and disturbed sleep pattern and leads to improved quality of life. Patient with previous PTBD or stenting who need secondary stenting for prolonged good clinical status.

PRIMARY ENDPOINT (Safety) The primary safety endoint is the proportion of subjects experiencing biliary and procedural complications (post-ERCP pancreatitis, bleeding, perforation (bile/duodenum), misplacement, migration, bile occlusion, duct abrasion, duodenal abrasion, cholangitis, severe pain) and all-death within 30 days of the index procedure.

SECONDARY ENDPOINT (Efficacy) Clinical success; normal serum bilirubin level within 14 days after onset of drainage. Relief of jaundice and pruritus.

Technical success; completion of initial ERCP and stent deployment. Procedural success; rating of stent criteria. Each criteria will be evaluated and rated as 1 for exellent, 2 for good, 3 for fair and 4 for poor.A procedure will be considered as successful if the combined rate is < 3.

Quality of life improvement by Self Assessment score at 1, 7, 14, 30, 90, 183, 274 and 365 days.

Biodegradation rate at 7, 14, 30, 90, 183, 274 and 365 days assesd by visual assessment at each follow-up visits when adequate examinations (X-ray, Endoscopy, MRI, CT, …) are performed.

Compiled Complication Rate at 7, 14, 90, 183, 274 and 365 days.