Final results of a phase I–II trial using ex vivo expanded autologous Mesenchymal Stromal Cells for the treatment of osteoarthritis of the knee confirming safety and suggesting cartilage regeneration

Cellular therapies have shown encouraging results in the treatment of chronic osteoarthritis (OA). Herein, we present the final results of a phase I–II clinical trial assessing the feasibility, safety and efficacy of ex vivo expanded autologous bone marrow Mesenchymal Stromal Cells (MSC, XCEL-M-ALPHA), infused intra-articularly, in patients with knee OA.

Fifteen patients (median age = 52 years) with grade II(9) or III(6) gonarthrosis (Kellgren & Lawrence classification) and chronic pain were treated with an intra-articular infusion of 40.9 × 10⁶ ± 0.4 × 10⁶ MSCin a phase I–II prospective, open-label, single-dose, single-arm clinical trial. Endpoints were safety and tolerability. Efficacy was measured by the Visual Analogue Scale for pain, algofunctional Health Assessment Questionnaire, Quality of Life (QoL) SF-36 questionnaire, Lequesne functional index and WOMAC score. Cartilage integrity was assessed by Magnetic Resonance Imaging and quantitative T2-mapping at 0, 6 and 12 months.

The cell-based product was well tolerated with few reported Adverse Events (mild arthralgia and low back pain). There was a relevant decrease in the intensity of pain since day 8 after the infusion, that was maintained after 12 months. The SF-36 QoL test showed improvement of parameters including bodily pain, role physical and physical functioning at month 12. The health assessment questionnaire revealed a significant decrease of incapacity. Moreover, T2 mapping showed signs of cartilage regeneration in all patients at 12 months post-treatment.

Single intra-articular infusion of XCEL-M-ALPHA is a safe and well-tolerated cell-based product, associated with a long-lasting amelioration of pain, improvement of QoL (up to four years), and signs of cartilage repair.