Five-Year Outcome of 1-Stage Cell-Based Cartilage Repair Using Recycled Autologous Chondrons and Allogenic Mesenchymal Stromal Cells: A First-in-Human Clinical Trial.

BACKGROUND: Long-term clinical evaluation of patient outcomes can steer treatment choices and further research for cartilage repair. Using mesenchymal stromal cells (MSCs) as signaling cells instead of stem cells is a novel approach in the field.
PURPOSE: To report the 5-year follow-up of safety, clinical efficacy, and durability after treatment of symptomatic cartilage defects in the knee with allogenic MSCs mixed with recycled autologous chondrons in first-in-human study of 1-stage cartilage repair. STUDY
DESIGN: Case series; Level of evidence, 4.
METHODS: This study is an investigator-driven study aiming at the feasibility and safety of this innovative cartilage repair procedure. Between 2013 and 2014, a total of 35 patients (mean ± SD age, 36 ± 8 years) were treated with a 1-stage cartilage repair procedure called IMPACT (Instant MSC Product Accompanying Autologous Chondron Transplantation) for a symptomatic cartilage defect on the femoral condyle or trochlear groove. Subsequent follow-up after initial publication was performed annually using online patient-reported outcome measures with a mean follow-up of 61 months (range, 56-71 months). Patient-reported outcome measures included the KOOS (Knee injury and Osteoarthritis Outcome Score), visual analog scale for pain, and EuroQol-5 Dimensions. All clinical data and serious adverse events, including additional treatment received after IMPACT, were recorded. A failure of IMPACT was defined as a chondral defect of at least 20% of the index lesion with a need for a reintervention including a surgical procedure or an intra-articular injection.
RESULTS: Using allogenic MSCs, no signs of a foreign body response or serious adverse reactions were recorded after 5 years. The majority of patients showed statistically significant and clinically relevant improvement in the KOOS and all its subscales from baseline to 60 months: overall, 57.9 ± 16.3 to 78.9 ± 17.7 (P < .001); Pain, 62.3 ± 18.9 to 79.9 ± 20.0 (P = .03); Function, 61.6 ± 16.5 to 79.4 ± 17.3 (P = .01); Activities of Daily Living, 69.0 ± 19.0 to 89.9 ± 14.9 (P < .001); Sports and Recreation, 32.3 ± 22.6 to 57.5 ± 30.0 (P = .02); and Quality of Life, 25.9 ± 12.9 to 55.8 ± 26.8 (P < .001). The visual analog scale score for pain improved significantly from baseline (45.3 ± 23.6) to 60 months (15.4 ± 13.4) (P < .001). Five cases required reintervention.
CONCLUSION: This is the first study showing the midterm safety and efficacy of the proof of concept that allogenic MSCs augment 1-stage articular cartilage repair. The absence of serious adverse events and the clinical outcome support the longevity of this unique concept. These data support MSC-augmented chondron transplantation (IMPACT) as a safe 1-stage surgical solution that is considerably more cost-effective and a logistically advantageous alternative to conventional 2-stage cell-based therapy for articular chondral defects in the knee.