A Study of MACI in Patients Aged 17 to 65 Years With Symptomatic Chondral or Osteochondral Defects of the Ankle

The objective of this study is to demonstrate the superiority of MACI (autologous cultured chondrocytes on porcine collagen membrane) versus Bone Marrow Stimulation in the treatment of patients aged 17 to 65 years with symptomatic articular chondral or osteochondral defects of the talus.

This is a 2-year prospective, multicenter, two-arm, parallel-group open-label clinical trial in which a total of 309 subjects, ages 17 to 65, will be randomized 2:1 to receive a 1-time treatment in the ankle with MACI or arthroscopic BMS. After meeting screening criteria at the initial visit (Visit 1), all subjects will have an index ankle arthroscopy within 8 weeks to further assess study eligibility. During the index ankle arthroscopy (Visit 2), patients will be further evaluated against entry criteria. Cartilage lesion size will be measured before any cartilage repair procedure and randomization. Only subjects with at least 1 lesion ≥ 1.2 cm² on the talus will be eligible for inclusion in the study. All subjects who meet the eligibility criteria and are considered suitable for treatment in the study by their surgeon will have a cartilage biopsy taken prior to randomization to study treatment. Eligible subjects will be randomized 2:1 to receive either MACI or Bone Barrow Stimulation. Subjects randomized to Bone Marrow Stimulation will undergo the procedure during the Visit 2 ankle arthroscopy. Subjects will be asked to follow a recommended postoperative rehabilitation program. All biopsied tissue will be sent to the Vericel Corporation manufacturing facility in Massachusetts, where the sample will be processed to isolate the autologous chondrocytes, undergo cell culture expansion through at least the primary phase, and cryopreservation. Additional expansion of the cells will occur after the MACI implantation surgery has been scheduled. Subjects assigned to the MACI treatment arm will return within 5-12 weeks of the Visit 2 ankle arthroscopy to undergo MACI implantation procedure via arthrotomy (Visit 3). Subjects will be asked to follow a recommended postoperative rehabilitation program. All subjects will be assessed post-study treatment at Weeks 6 and 12 for safety and at Weeks 24, 36, 52, 78, and 104 for safety and efficacy. Rehabilitation status will be monitored at all post-treatment visits until considered complete.