FDA Greenlights Groundbreaking Acellular Tissue Engineered Vessel for Vascular Trauma Treatment

FDA Approves the First Acellular Tissue Engineered Vessel

On December 20, 2024, the U.S. Food and Drug Administration (FDA) made a groundbreaking announcement by approving Symvess, the first acellular tissue engineered vessel intended for adult patients suffering from vascular trauma in extremities. This innovative product aims to serve as a vascular conduit necessary for urgent revascularization when traditional methods such as autologous vein grafts are not viable.

Vascular trauma refers to injuries sustained by blood vessels, including ruptured arteries in the extremities, which pose substantial risks such as severe hemorrhaging or blood clot development. When an artery is compromised, immediate surgical intervention is crucial for restoring healthy blood circulation. Typically, the standard treatment methods for such injuries include autologous vein grafting or the implantation of synthetic grafts, neither of which may be suitable or available for all patients.

The approval of Symvess brings an important alternative to the current treatment landscape. According to Dr. Peter Marks, director of the FDA's Center for Biologics Evaluation and Research (CBER), "Today's approval provides an important additional treatment option for individuals with vascular trauma, produced using advanced tissue engineering technology." Dr. Marks emphasizes the FDA's dedication to promoting the development of innovative products that can yield life-saving outcomes for individuals with severe injuries.

Symvess is a sterile, acellular tissue engineered vessel created from human extracellular matrix (ECM) proteins typically found in human blood vessels. Its innovative manufacturing process employs human vascular smooth muscle cells, derived from human aortic tissue. Operatively, Symvess is a single-use product meant to replace damaged blood vessels following traumatic injuries in extremities.

Presently, the options available for treating vascular trauma are inadequate, often leading to serious and potentially life-threatening complications. Dr. Nicole Verdun, director of the Office of Therapeutic Products in CBER, emphasizes this gap in treatment: "Currently available treatment options are limited for vascular trauma, which can lead to severe and potentially life-threatening complications. Today's decision to approve a new therapeutic product based on novel medical technology represents important progress in addressing a significant unmet medical need."

The efficacy of Symvess was established through a prospective, single-arm, multicenter study involving patients with life- or limb-threatening vascular trauma. Of the 54 patients included in the study, 36 (67%) maintained primary patency, indicating adequate blood flow without further intervention, while 39 (72%) retained secondary patency, which necessitated at least one additional procedure within 30 days of implantation. Nevertheless, five patients (9%) required amputation within the first month post-implantation, and by the end of the three-year study, eight (15%) patients had undergone amputation.

As with any medical product, Symvess poses potential risks, the most frequent of which include thrombosis (the formation of blood clots within the implanted vessel), fever, pain, and abnormalities where the vessel is sewn into the patient’s blood vessel. Serious risks can involve graft rupture, anastomotic failure, and thrombosis. Additionally, since Symvess is manufactured utilizing human and bovine cells, there is a risk of transmitting infectious diseases. It’s important to note that the cells used are sourced from donors meeting strict eligibility criteria to mitigate this concern.

The application for Symvess received a Priority Review and Regenerative Medicine Advanced Therapy (RMAT) designation. It's also recognized as a Priority Product by the U.S. Department of Defense (DoD), which underscores its importance in addressing life-threatening conditions faced by military personnel. This expedited development and review process is part of a Public Law that authorizes the DoD to request and the FDA to provide assistance with products designed to combat severe diseases.

Honorably, the FDA granted approval for Symvess to Humacyte Global, Inc., marking a significant advancement in vascular trauma treatment options.