SUMMARY: Orthopedic surgeons reported that 85 percent of patients treated with Carticel® to repair damaged cartilage on the thigh-bone part of the knee showed improvement in four key measures four years after therapy. Carticel is indicated for the repair of damaged cartilage on the thigh bone part of the knee caused by acute or repetitive trauma, in patients who have had an inadequate response to a prior arthroscopic or other surgical repair procedure.
CAMBRIDGE, MA — March 20, 2000 — Orthopedic surgeons reported that 85 percent of patients treated with Genzyme Tissue Repair’s Carticel® autologous cultured chondrocytes to repair damaged cartilage on the thigh-bone part of the knee showed improvement in four key measures four years after therapy.
This result is reported in the summary of the sixth report of Genzyme Tissue Repair’s Cartilage Repair Registry presented today by Bert Mandelbaum, M.D. of the Santa Monica Orthopedic and Sports Medicine Group during the annual meeting of the American Academy of Orthopedic Surgeons in Orlando.
Carticel is indicated for the repair of damaged cartilage on the thigh bone part of the knee caused by acute or repetitive trauma, in patients who have had an inadequate response to a prior arthroscopic or other surgical repair procedure.
The Cartilage Repair Registry chronicles the progress of patients treated with Carticel, a therapy that employs a proprietary process to grow a patient’s own cartilage to repair certain types of knee cartilage damage. Previous reports of the registry had shown improvement at three years after surgery. The sixth report is the first to include data from patients four years after surgery.
The sixth registry report included data collected on 47 patients at the 48-month follow-up visit over four key measures: clinician and patient evaluations of overall knee condition, patient reports of symptoms, such as pain and swelling, and knee examination results.
The clinician and patient evaluations of overall knee condition were scored using a modified Cincinnati knee scoring system, a rating method widely recognized by orthopedic surgeons. Under that system, a score of two represents poor condition, four is fair, six is good, eight is very good, and 10 is excellent. Patients with poor to fair ratings had significant to moderate limitations in daily activities and were not able to participate in sports. Patients who were rated good had no limitations in daily activities and could participate in sports with compensation for limitations. Patients rated as very good could participate in sports with only a few limitations, and patients rated as excellent were able to participate in whatever sport they wished to with no problem.
Among the 47 patients with 48-month data, clinician and patient evaluations using the Cincinnati scale increased from averages of 3.0 and 3.0 before treatment to 6.8 and 6.0 at 48 months after treatment. Results at 12, 24, 36, and 48 months for this group of patients in either the clinician or patient evaluation indicate that improvements noted at 12 months were sustained at 48 months.
On a scale where zero represents severe symptoms and 10 indicates no symptoms, patients reported that 48 months after surgery, pain improved by an average of 2.3 points, swelling improved by an average of 3.2 points, partial giving way of the knee improved by an average of 3.3 points, and full giving way of the knee improved by an average of 1.9 points. With symptoms, as with overall knee condition, there was little difference between the results at 12 months and those at 48 months indicating that improvement was sustained.
Knee examinations revealed major decreases in joint line pain and effusion, and increases in range of motion, at 12, 24, 36, and 48 months, compared to examinations done prior to treatment. The percentage of knees with joint line pain upon clinical examination decreased from 87 percent before surgery to 35 percent at 48 months. The percentage with effusion — swelling measured by the surgeon’s examination — decreased from 74 percent of knees before treatment to 29 percent at 48 months after treatment.
Data from the report also show that of all patients treated with Carticel worldwide as of November 1999, 92 percent reported no complications, and 4 percent reported an adverse event determined by the treating surgeon to be at least possibly related to Carticel. The cumulative incidence of treatment failure was estimated to be 2.1 percent at 24 months, 2.7 percent at 36 months, and 3.2 percent at 48 months.
A treatment failure occurs if another surgical procedure – either a reimplantation of Carticel or a procedure that violates the subchondral bone – is performed to treat the defect, or if there has been a complete removal of the Carticel graft.
Since the start of the registry, 94 percent of patients have reported no additional surgical procedures following implantation of Carticel. The majority of operations following Carticel implantation were minor and were performed using an arthroscope.
The most frequent adverse events reported in the registry include adhesions and overgrown tissue at the cartilage repair site and loosening of the Carticel graft.
The data reported in the registry are observational in nature. The observed changes may be due, at least in part, to factors other than the autologous chondrocyte implantation procedure.
The registry is not a controlled clinical study. Patient participation is voluntary. In addition, the report does not contain arthroscopic or histological data. Genzyme Tissue Repair is conducting a controlled clinical study of Carticel and will report on patients up to four years after treatment.
Carticel was licensed by the U.S. Food and Drug Administration in August 1997, and is indicated for the repair of defects on the femoral condyle, or thigh-bone part of the knee, who have had an inadequate response to a prior arthroscopic or other surgical repair procedure. It is not indicated for the treatment of cartilage damage associated with osteoarthritis.
Members of the registry’s independent advisory panel are Jon E. Browne, M.D., clinical associate professor, University of Missouri at Kansas City and University of Kansas, and director, Orthopedic Sports Medicine Fellowship Program, University of Missouri at Kansas City; Christoph Erggelet, M.D., Ph.D., Department of Orthopedics, University of Freiburg, Freiburg, Germany; Freddie Fu, M.D., chairman, Department of Orthopedic Surgery, University of Pittsburgh; Bert R. Mandelbaum, M.D., Santa Monica Orthopedic and Sports Medicine Group, and director of fellowship, Santa Monica Orthopedic and Sports Medicine Group, Santa Monica, Calif.; Lyle J. Micheli, M.D., director, Division of Sports Medicine, Children’s Hospital, and associate clinical professor, Harvard Medical School, Boston; and J. Bruce Moseley Jr., M.D., Baylor Sports Medicine Institute, Baylor College of Medicine, Houston.