The U.S. Food and Drug Administration today approved Maci (autologous cultured chondrocytes on porcine collagen membrane) for the repair of symptomatic, full-thickness cartilage defects of the knee in adult patients. Maci is the first FDA-approved product that applies the process of tissue engineering to grow cells on scaffolds using healthy cartilage tissue from the patient’s own knee.
Knee problems are common, and occur in people of all ages. Cartilage defects in the knee can result from an injury, straining the knee beyond its normal motion, or can be caused by overuse, muscle weakness, and general wear and tear.
“Different cartilage defects require different treatments, so therapy must be tailored to the patient,” said Celia Witten, Ph.D., M.D., deputy director of the FDA’s Center for Biologics Evaluation and Research. “The introduction of Maci provides surgeons with an additional option for treatment.”
Maci is composed of a patient’s own (autologous) cells that are expanded and placed onto a bio-resorbable (can be broken down by the body) porcine-derived collagen membrane that is implanted over the area where the defective or damaged tissue was removed. Administration should be performed by a surgeon specifically trained in the use of Maci.
Each Maci implant consists of a small cellular sheet containing 500,000 to 1,000,000 cells per cm2 (about 0.16 square inches). The amount of Maci administered depends on the size of the cartilage defect, and is trimmed to ensure that the damaged area is completely covered. Multiple implants may be used if there is more than one defect.
The safety and efficacy of Maci were shown in a two-year clinical trial designed to demonstrate reduced pain and improved function in comparison to microfracture, an alternative surgical procedure for cartilage repair. The trial included 144 patients (72 in each treatment group). A majority of the patients who completed the two-year clinical trial also participated in a three year follow-up study. Overall efficacy data support a long-term clinical benefit from the use of the Maci implant in patients with cartilage defects.
The most common side effect reported by people who received Maci were: joint pain, common cold-like symptoms, headache and back pain.
Maci is manufactured by Vericel Corporation, headquartered in Cambridge, Massachusetts.
The FDA, an agency within the U.S. Department of Health and Human Services, protects the public health by assuring the safety, effectiveness, and security of human and veterinary drugs, vaccines and other biological products for human use, and medical devices. The agency also is responsible for the safety and security of our nation’s food supply, cosmetics, dietary supplements, products that give off electronic radiation, and for regulating tobacco products.
Autologous chondrocyte transplantation has become an established therapy for full-thickness cartilage defects. Cell-seeded collagen matrix–supported autologous chondrocyte transplantation (ACT-CS) has been introduced as a modification of conventional ACT, which allows easier handling and is intended to combine the advantages of using a cell suspension (i.e., cell viability and mitotic activity) with the stability and self-containment provided by a matrix of biomaterials. Unlike other techniques and products, this seeding step can be easily applied using a porcine collagen type I/III membrane and autologous chondrocytes in an operating room setting. Although some suturing is required, this technique provides the distinct advantage of not requiring a water-tight seal of the bilayer membrane, as is required using the classic cell suspension technique. Comparable to other modifications of ACT, the ACT-CS procedure requires a specific surgical technique that focuses on the following important details: (1) accurate debridement of the cartilage defect; (2) preparation of the cells, and seeding and containment of the cells within the transplantation site; and (3) sealing and suturing around the defect.