FDA provides 510(k) clearance for Boston Scientific's WallFlex Biliary RX covered stents

Boston Scientific Corporation (NYSE: BSX) today announced that it has received 510(k) clearance from the U.S. Food and Drug Administration (FDA) to market its WallFlex(®) Biliary RX fully and partially covered stents for the palliative treatment of malignant bile duct strictures. The WallFlex Biliary RX uncovered stent was cleared by the FDA in 2006. All three models of the WallFlex Biliary RX Stenting System -- fully covered, partially covered and uncovered -- are now available in both the United States and Europe.

"The WallFlex Biliary RX Stent System represents the next stage in self-expandable metal stent technology. The stent has greater flexibility to aid with placement in tortuous anatomies and new features such as flared ends that may reduce the risk of migration," said Kenneth F. Binmoeller, M.D., Director of Interventional Endoscopy at California Pacific Medical Center, and an investigator for the WallFlex Biliary RX fully covered stent study.

The WallFlex Biliary RX Stent is designed to offer the benefits of prior-generation stents, such as the industry-leading WALLSTENT(®) Endoprosthesis, while incorporating new features to accommodate a range of anatomical and clinical requirements. Based on extensive research and physician feedback, the WallFlex Biliary RX Stent employs a platinum-cored Nitinol construction designed to deliver on three critical components: radial force, flexibility and radiopacity. The Platinol(TM) Wire provides greater flexibility - 30 percent more than the WALLSTENT Endoprosthesis - to help the stent conform within tortuous anatomies. The enhanced full-length radiopacity offered by the Platinol Wire and the reconstrainable delivery system are designed to allow for more precise stent placement, while the radial force of the WallFlex Biliary RX Stent is designed to maintain patency and resist migration.

TheWallFlex Biliary RX Stents also feature a closed-cell construction designed to resist tissue ingrowth, looped ends intended to reduce the risk of tissue trauma, and flared ends to help reduce the risk of stent migration. The proprietary, durable silastic polymer (Permalume(®)) covering of the fully and partially covered stents is designed to reduce the potential for tumor ingrowth. In addition, the WallFlex Biliary RX Stent incorporates an integrated retrieval loop for removal during the initial stent placement procedure, which can be used in the event of incorrect placement.

"Boston Scientific continues to fulfill our promise to deliver industry-leading, innovative technologies that enable physicians to best diagnose and treat digestive diseases, and enhance quality of life for patients," said Michael Phalen, President, Boston Scientific Endoscopy. "The WallFlex Biliary RX Stent leverages existing Boston Scientific technologies, while advancing performance with new features such as a unique Platinol Wire construction. We believe we are truly delivering the next generation of stents for the treatment of malignant bile duct strictures."

Preliminary results from Dr. Petersen's study were reported at United European Gastroenterology Week (UEGW) in 2008. Results showed that the fully covered WallFlex Biliary RX Stent yielded technically successful placement, low rates of re-intervention (two percent) and recurrent biliary obstruction, and minimal occurrence of migration (two percent) and complications. With 98 percent of patients meeting the primary endpoint of clinical palliation of the biliary obstruction until completion of follow-up, study results suggest that the fully covered WallFlex Biliary RX Stent may successfully palliate most patients with malignant distal biliary obstructions.

Also presented at UEGW were preliminary data on a 70-patient WallFlex Biliary RX partially covered stent study led by Primary Investigator Guido Costamagna, M.D., Head of Digestive Endoscopy at Universita Cattolica del Sacro Cuore in Rome. Preliminary results of the study demonstrate that the partially covered metal stent may palliate most patients with malignant biliary obstructions.

The safety and effectiveness of the WallFlex Biliary RX Stenting System for use in the vascular system have not been established.