Genzyme Corp (CAMBRIDGE, Massachusetts) announced findings from a large, multicenter, observational study that investigated the long-term durability of Carticel^® (autologous cultured chondrocytes) in patients who had pain and functional impairment in the articular cartilage of their knee. The findings revealed that almost 90% of patients treated with Carticel who experienced improvement in knee function at an early follow-up, sustained their improvement for almost 10 years.

The objectives of the study were to determine if a patient’s improvement assessed at early follow-up, defined as 1 to 5 years (mean 4.6 years) after autologous chondrocyte implantation (ACI), could be sustained at later follow-up of 6 to 10 years (mean 9.2 years). A cohort of 72 patients with low functional scores (overall condition score of 3.4 points on the Modified Cincinnati Knee Rating System) was enrolled from 35 centers across the US. Patients were young (mean age 37) and had moderate-to-large lesions (mean lesion size 4.3 cm2) on the femoral chondyles (lateral femoral chondyle, medial femoral chondyle, and trochlea) and most patients had undergone at least 1 previous treatment for their cartilage injury. At early follow-up, 75% of patients experienced significant improvement in their knee function (mean improvement 4.3 in overall condition); of those patients, 87% sustained improvement at later follow-up.

Genzyme also announced the findings of a separate study that compared the results of ACI following a marrow stimulation technique (eg, microfracture) versus no significant treatment (including simple debridement) performed on the same cartilage defect. The results indicate that marrow stimulation techniques may compromise the successful outcome of future ACI. Investigators collected data from 329 consecutive patients treated with Carticel for large and multiple defects (4.8 cm2 per lesion and 8.7 cm2 per patient) and who had at least 2 years’ follow-up. They concluded that patients who had a previous marrow stimulation technique and were subsequently treated with ACI were 3 times more likely to fail than patients who had not undergone a marrow stimulation technique prior to ACI treatment.

The implant is indicated for the repair of symptomatic cartilage defects of the femoral condyle, caused by acute or repetitive trauma in patients who have had an inadequate response to a prior arthroscopic or other surgical repair procedure (eg, debridement, microfracture, drilling/abrasion arthroplasty, or osteochondral allograft/autograft). The procedure should only be used in conjunction with debridement, placement of a periosteal flap, and rehabilitation. The independent contributions of the autologous cultured chondrocytes and other components of the therapy to outcome are unknown. It is neither indicated for the treatment of cartilage damage associated with generalized osteoarthritis nor is it recommended for patients whose knee meniscus has been surgically removed unless the patient has undergone surgical reconstruction prior to or concurrent with Carticel implantation.

Pre-existing conditions including meniscal tears, joint instability, or malalignment of the joint should be corrected prior to or concurrent with Carticel implantation. The implant should not be used in patients with a known history of hypersensitivity to gentamicin or other aminoglycosides, or materials of bovine origin.

Carticel was the first cell therapy approved by the US FDA. First introduced in March 1995, the procedure received accelerated approval from the FDA in August 1997, after which the agency instituted specific cell therapy guidelines and required Genzyme to conduct confirmatory postmarketing clinical studies. Genzyme successfully completed the confirmatory studies and, in June 2007, the FDA deemed the commitment satisfied. More than 14,000 patients in the US have Carticel implants.