Intra-Articular Injection of Autologous Adipose Tissue-Derived Mesenchymal Stem Cells for the Treatment of Knee Osteoarthritis: A Phase IIb, Randomized, Placebo-Controlled Clinical Trial

Lee WS, Kim HJ, Kim KI, et al. · Stem Cells Translational Medicine

The prespecified primary endpoint is a within-group change - the difference in WOMAC score between baseline and 6 months - and the cell arm met it: WOMAC fell 55%, from 60.0 +/- 17.0 to 26.7 +/- 13.3 (p<.001), with VAS pain from 6.8 +/- 0.6 to 3.4 +/- 1.5, while the placebo arm moved significantly on no symptom score. The paper reports no between-group test of any symptom score. Its one between-group comparison is structural: cartilage defect size was unchanged on cells (p=.5803) and larger on placebo (p=.0049), the difference in change reaching p=.0051.

Population

24 patients with KL grade 3 knee OA (12 per arm)

Intervention

Single injection of 100 million culture-expanded autologous adipose-derived MSCs

Comparator

Saline placebo (double-blind)

Limitations

Twelve patients per arm, and the power calculation that sized them targeted a within-group change, returning five per arm; the endpoint is 6 months. Supported by R-Bio, the cell manufacturer, whose chief executive is thanked in the acknowledgements, with three authors reporting research grants from the same company. Adverse events were more frequent on cells than placebo (10 of 12 against 7 of 12, treatment-related in 8 against 1); all resolved and none were serious.