FDA Approves Autologous Cartilage Implant

The FDA recently approved the first autologous cellularized scaffold for the repair of knee cartilage in adult patients with damaged or defective tissue.

Maci (autologous cultured chondrocytes on porcine collagen membrane) is indicated for the repair of symptomatic, full-thickness cartilage defects in the knee. The approval makes Maci the first FDA-approved product that uses tissue engineering to grow cells on scaffolds using healthy cartilage tissue derived from the patient’s knee, the FDA reported in a press release.

Knee problems can occur in many individuals, regardless of age. Cartilage defects can result from previous injury, knee strain, overuse, muscle weakness, or even from normal use.

Maci uses autologous cells, which are the patient’s own cells, that are expanded and placed onto an absorbable porcine-derived collagen membrane, according to the FDA. Since the membrane can be absorbed by the body, a long-term device does not need to be implanted into the knee.

The collagen membrane will instead be implanted into the area where the damaged cartilage tissue has been removed. Only surgeons who are specifically trained in Maci should implant the device into patients with defective or damaged knee cartilage tissue, the FDA said.

Each implant is a small cellular sheet that contains 500,000 to 1,000,000 per cm², the FDA reported. The amount of Maci implanted is individualized for each patient, since it depends on the size of the needed implant.

The Maci implant is trimmed to ensure that the size of the defect is completely covered, and patients may even receive multiple implants if there are multiple defects.

The safety and efficacy of the device were shown in a 2-year clinical trial that found patients experienced less pain and improved function compared with an alternative microfracture procedure. There were 144 patients included in the study, half of whom received Maci.

Overall long-term data supported the clinical benefit of Maci implants in patients with knee cartilage defects, according to the FDA.

Common adverse events seen in the trial were joint pain, common cold-like symptoms, head pain, and back pain.

“Different cartilage defects require different treatments, so therapy must be tailored to the patient,” said Celia Witten, PhD, MD, deputy director of the FDA’s Center for Biologics Evaluation and Research. “The introduction of Maci provides surgeons with an additional option for treatment.”