FDA Approves Engineered Vessels to Treat Vascular Trauma

WASHINGTON — The Food and Drug Administration on Friday approved the first engineered vessel made from acellular tissue for the treatment of extreme arterial injuries when other steps can’t be taken to avoid imminent limb loss.

Symvess, manufactured by Humacyte Global, Inc., are tissue structures designed to resemble the body’s natural vasculature and aim to restore, replace, or enhance the function of damaged or diseased vascular tissue.

With its approval, surgeons now have an alternative means of restoring blood flow to the extremities when vein grafts using tissue from the same patient are not feasible.

“Today’s approval provides an important additional treatment option for individuals with vascular trauma, produced using advanced tissue engineering technology,” said Dr. Peter Marks, Ph.D., director of the FDA’s Center for Biologics Evaluation and Research. 

“The FDA remains committed to facilitating the development of innovative products that offer potentially life-saving benefits for patients with severe injuries,”  Marks said.

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 surgical repair using the patient’s own blood vessels or implantation of a synthetic graft. But these treatments are not suitable or available for every patient.

Humacyte’s Symvess is a sterile, acellular tissue engineered vessel composed of human extracellular matrix 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 Dr. Nicole Verdun, director of the Office of Therapeutic Products in the FDA’s Center for Biologics Evaluation and Research.

“Today’s decision to approve a new therapeutic product based on novel medical technology represents important progress in addressing a significant unmet medical need,” she said.

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 blood clots, 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.

In a written statement, Dr. Laura Niklason, Ph.D., founder and chief executive officer of Humacyte said she and her colleagues were “very excited” and “proud” to be providing patients suffering from arterial injury with a novel treatment option.

“Symvess has been made possible by our innovative bioengineering science along with the contributions of many patients, healthcare providers and Humacyte team members.” Niklason said, calling its approval “a milestone for regenerative medicine overall, as well as for Humacyte.” 

“The FDA’s full approval of Symvess is a transformational event for the company and our bioengineering technology platform,” she continued. “Even more importantly, we believe Symvess provides a new means of treating patients with devastating arterial injuries, which is a population that has not benefited from substantial innovation in decades.”

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