Safety and efficacy of an iBTA-induced autologous Biotube® vascular graft and its preparation device BTM1 in below-the-knee bypass surgery for chronic limb threatening ischemia: A protocol for an open-label, single-arm, multicenter clinical trial

Abstract

Abstract Background: Chronic limb-threatening ischemia (CLTI) increases the risk of lower limb amputation if revascularization is not performed properly at an early stage. The use of autologous venous conduits is the only option, especially for critically ill patients requiring below-the-knee bypass surgery, but it is limited by a lack of usable veins. Biotube Maker (BTM1), which is based on so-called in-Body Tissue Architecture (iBTA) technology, is a mold for the in vivo production of the Biotube® regenerative artificial vascular grafts. An autologous small diameter, long-length Biotube for lower limb bypass is prepared by subcutaneous embedding of the Maker for 1–2 months. This clinical trial based on an extremely specialized therapy that can prepare an autologous implantable tissue in the patient’s body. It is designed to evaluate the safety and efficacy of subcutaneous embedding of the BTM1 for Biotube preparation, and arterial bypass surgery at the lower limb for CLTI patients using Biotube obtained from the BTM1. Methods: This trial is intended for patients with CLTI without optimal veins available for bypass surgery. The medical device to be evaluated is the BTM1, which is used to prepare Biotubes. The obtained Biotubes will also be evaluated. This is an exploratory investigator-initiated clinical trial of an open-label and uncontrolled medical device, which will be conducted in a multicenter setting. The planned number of subjects for this study is 12. The primary efficacy endpoint is the ability to form of an implantable Biotube from the BTM1 embedded subcutaneously in patients. The safety and efficacy of the resulting Biotubes will be evaluated by performing bypass surgery to the lower leg below the knee or foot artery. The biocompatibility and patency of the Biotubes, and wound healing, improvement of resting pain and limb salvage, and procedure-related death, will be confirmed up to 12 weeks after surgery. Discussion: These findings may be promising for patients with CLTI who have no choice except to have their legs amputated. This study should be followed by a pivotal study to obtain satisfactory data for an application for marketing approval. Trial registration: jRCT2072220062. Registered on October 19, 2022.