The U.S. Food and Drug Administration approved Symvess, the first acellular tissue engineered vessel indicated for use in adults as a vascular conduit for extremity arterial injury when urgent revascularization (restoration of blood flow) is needed to avoid imminent limb loss, and autologous vein graft is not feasible.

Vascular trauma occurs when a blood vessel is injured such as a rupture of an artery in the extremities, which can lead to serious, life-threatening complications such as hemorrhage or blood clotting. When damage to an artery in the extremity occurs, urgent surgical repair is needed to restore normal blood flow. The current standard of care for patients with extremity vascular injuries can include procedures such as autologous vein grafting (surgical repair using the patient’s own blood vessels) or implantation of a synthetic graft. These treatments are not suitable or available for every patient.

“Today’s approval provides an important additional treatment option for individuals with vascular trauma, produced using advanced tissue engineering technology,” said Peter Marks, M.D., Ph.D., director of the FDA’s Center for Biologics Evaluation and Research (CBER). “The FDA remains committed to facilitating the development of innovative products that offer potentially life-saving benefits for patients with severe injuries.”  

Symvess is a sterile, acellular tissue engineered vessel composed of human extracellular matrix (ECM) proteins typically found in human blood vessels. It is manufactured using a tissue engineering process utilizing human vascular smooth muscle cells derived from human aortic tissue. Symvess is a one-time, single-use product surgically implanted to replace a patient’s damaged blood vessel after a traumatic injury to the extremity.

“Currently available treatment options are limited for vascular trauma, which can lead to severe and potentially life-threatening complications,” said Nicole Verdun, M.D., director of the Office of Therapeutic Products in CBER. “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 safety and effectiveness of Symvess was assessed based on data from a prospective, single arm, multicenter study in patients with life- or limb-threatening vascular trauma. A total of 54 patients received Symvess to repair an arterial vessel in the extremity. Efficacy was evaluated based on primary patency (blood flow present without any intervention) and secondary patency (at least one intervention required to maintain blood flow) 30 days after implantation. Of the 54 patients evaluated, 36 (67%) retained primary patency and 39 (72%) retained secondary patency at day 30. Five patients (9%) underwent amputation of the treated limb within the first 30 days and eight (15%) patients underwent amputation of the treated limb by end of study (month 36).

The most common adverse reactions of Symvess are thrombosis (blood clot in Symvess), fever, pain, anastomotic stenosis (abnormal narrowing where the Symvess was sewn to the patient’s blood vessel). The serious risks of Symvess include graft rupture, anastomotic failure and thrombosis. Because Symvess uses cells from a human donor and reagents of human and bovine (cow) origin, transmission of infectious diseases or infectious agents can occur. The cells used in the manufacture of Symvess are derived from a donor who meets the donor eligibility requirements in place to prevent transmissible infectious diseases.

The application received Priority Review, Regenerative Medicine Advanced Therapy (RMAT) designation and is designated as a Priority Product by the U.S. Department of Defense (DoD). Public Law 115-92 authorized DoD to request, and the FDA to provide, assistance to expedite development and the FDA’s review of products to diagnose, treat or prevent serious or life-threatening diseases or conditions facing American military personnel.

The FDA granted approval of Symvess to Humacyte Global, Inc.

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