Mallinckrodt plc, a global biopharmaceutical company, today announced that the U.S. Food and Drug Administration (FDA) has approved StrataGraft® (allogeneic cultured keratinocytes and dermal fibroblasts in murine collagen – dsat) for the treatment of adults with thermal burns containing intact dermal elements for which surgical intervention is clinically indicated (deep partial-thickness burns).
This project was funded in part with $86 million from the Biomedical Advanced Research and Development Authority (BARDA), part of the Office of the Assistant Secretary for Preparedness and Response at the U.S. Department of Health and Human Services (HHS), under contract HHSO100201500027 for Stratatech Corporation, a Mallinckrodt company, to develop StrataGraft.
The FDA approval is supported by data from the pivotal Phase 3 STRATA2016 clinical trial of a single application of StrataGraft in patients with acute thermal burns containing intact dermal elements (deep partial-thickness burns) involving 3%-37% total body surface area, which was conducted at U.S. burn centers. Results, which were recently published in Burns, showed a significantly smaller area of burn wounds treated with StrataGraft required autografting by 3 months compared to the area of burn wounds treated exclusively with autograft (p<0.0001).
“While autografting is effective in providing closure of the original wound in patients with deep partial-thickness burns, it can lead to donor site complications, including pain, itching, increased risk of infection and scarring,” said Tracee Short, M.D., burn surgeon and burn unit medical director at the Regional Burn Center at Baton Rouge General. “The approval of StrataGraft represents an important advancement in the treatment of patients with deep partial-thickness burns. Burn surgeons will now have a new biologic treatment to eliminate or reduce the need for autografting.”
Each year, approximately 40,000 patients in the United States require hospitalization for the treatment of severe burns. Autograft is the current standard of care for deep partial-thickness burns – complex skin injuries in which the damage extends through the entire epidermis (outermost layer of skin) and into the lower part of the dermis (innermost layer of skin). Autograft involves the surgical harvesting of healthy skin from an uninjured site on the patient and transplanting the skin graft to the injury, creating a donor site wound and leaving the patient with more wounded areas requiring care.
“Today’s FDA approval of StrataGraft marks a significant milestone for the burn care community and underscores our unwavering commitment and ability to bring paradigm-changing treatment options to patients with severe and critical conditions,” said Steven Romano, M.D., Executive Vice President and Chief Scientific Officer at Mallinckrodt. “We are deeply appreciative of the patients who participated in the StrataGraft clinical trials, the physicians and study investigators involved in the clinical development program, and our employees, who have worked tirelessly over the last 20 years to help us bring StrataGraft to burn surgeons and the patients they treat.”
In the pivotal Phase 3 clinical trial, 96% (68 of 71) of the StrataGraft-treated burn sites across all participants did not require autografting. The difference in the percent area of StrataGraft and control autograft treatment sites that required autografting by 3 months was 98% (p<0.0001). The proportion of patients achieving durable closure of the StrataGraft treatment site at 3 months without autograft placement was 83% (95% CI: 74, 92). The proportion of patients achieving durable closure of the autograft control treatment site at 3 months without additional autograft placement was 86% (95% CI: 78, 94).
“Multiple health security threats can result in severe burn wounds, and, to save lives in a public health emergency, healthcare providers need products that are effective and easy to use,” said BARDA Director Gary Disbrow, Ph.D. “Having new products available on the commercial market to improve routine care for burn patients gives healthcare providers a level of familiarity and comfort in using the products. This improves our healthcare response during a national emergency and reduces the long-term cost of national preparedness.”
Clinical trials demonstrated that the safety profile of StrataGraft with regard to wound-related events, including erythema, swelling, local warmth and wound site infections, was comparable to that of autografting in clinical studies. The most common (>2%) adverse reactions were pruritus (itching), blisters, hypertrophic scar and impaired healing. There were no reports of rejection to StrataGraft in the clinical studies, and no patients discontinued study participation due to adverse reactions.
StrataGraft is a viable, bioengineered, allogeneic, cellularized scaffold product derived from keratinocytes grown on gelled collagen containing dermal fibroblasts. StrataGraft is designed to deliver viable cells to support the body’s own ability to heal. StrataGraft contains metabolically active cells that produce and secrete a variety of growth factors and cytokines. Growth factors and cytokines are known to be involved in wound repair and regeneration. The product is designed with both dermal and epidermal layers composed of well-characterized human cells. StrataGraft is intended to be applied in appropriate aseptic conditions, such as the operating room, and can be sutured, stapled or secured with a tissue adhesive.
The FDA granted StrataGraft orphan drug designation, and it was among the first products designated by the Agency as a Regenerative Medicine Advanced Therapy (RMAT) under the provisions of the 21st Century Cures Act. At the time of approval, the FDA awarded Stratatech Corporation, a Mallinckrodt company, a Priority Review Voucher (PRV).
Mallinckrodt is currently conducting a StrataGraft continued access clinical trial (StrataCAT, NCT04123548) under an Expanded Access Program (EAP). The trial sites involved in the pivotal Phase 3 trial (STRATA2016, NCT03005106) have the opportunity to participate in this multicenter, open-label study. The company is planning to evaluate StrataGraft for the treatment of adults with full-thickness burns (also referred to as third-degree burns).
Additionally, Mallinckrodt plans to conduct a study evaluating StrataGraft in the treatment of pediatric populations. The safety and effectiveness of StrataGraft in pediatric patients (<18 years) have not been established.
BARDA expressed interest in StrataGraft as a medical countermeasure in response to large-scale burn incidents, and provided funding and technical support for the continued development of StrataGraft. These efforts are part of BARDA’s strategy to build emergency preparedness in response to mass casualty events involving trauma and thermal burns by developing novel medical countermeasures for adult and at-risk populations. In the case of a mass casualty thermal burn event, the Government Accountability Office estimates that more than 10,000 patients might require thermal burn care. The limited number of specialized burn centers and related medical infrastructure in the United States creates a public health need for therapies that could be deployed quickly for use in these and other care sites.