Allogeneic Adipose-Derived Mesenchymal Stem Cells (Horse Allo 20) for the Treatment of Osteoarthritis-Associated Lameness in Horses: Characterization, Safety, and Efficacy of Intra-Articular Treatment.

Osteoarthritis commonly causes lameness in the horse and has a great impact in performance animals. Due to the limitations of current medical therapies, allogenic mesenchymal stem cells (MSCs) may become an alternative method to control inflammation, reduce tissue damage and pain, and therefore improve lameness. We present the results of a regulatory clinical trial testing adipose-derived MSCs (Horse Allo 20) in veterinary (Agencia Española del Medicamento y Productos Sanitarios, Spanish Medicines Agency, Reference number 325/ECV) involving a total number of 80 participants and with 90 days of follow-up period. The manufacturing process of Horse Allo 20 was robust with no influence of the adipose tissue donor (gender, age, or breed), sample origin (intraperitoneal or subcutaneous), or storage conditions (fresh vs. frozen product presentations) on the quality, safety, and efficacy of the drug product. An in vivo safety study showed that local and systemic tolerance was safe even after repeated intra-articular administration (three injections). An in vivo efficacy study demonstrated the efficacy of the treatment after one or two injections by a reduction in lameness (P < 0.05) for an extended period of time (90 days), decreasing the need for prolonged local and/or systemic anti-inflammatory therapies and their well-known deleterious effects and toxicities.