Efficacy and Safety Study of Intra-Articular Injections of Autologous Peripheral Blood Stem Cells Following Subchondral Drilling Surgery for the Treatment of Articular Cartilage Injury in the Knee

This is a 24-month, multicenter, randomized, open-label, standard treatment-controlled, parallel-group, Phase 2 study for adults with large or complicated knee articular cartilage lesions and are candidates for knee joint cartilage repair surgery. The safety and efficacy of intra-articular injections of peripheral blood stem cells (PBSCs) together with hyaluronic acid (HA) after subchondral drilling surgery will be evaluated to determine whether PBSC therapy can improve functional outcome and reduce pain of the knee joint better than a standard treatment (HA injections and physiotherapy regimen).

• Autologous peripheral blood stem cells and hyaluronic acid (Biological): Regimen of intra-articular PBSC and HA injections and postoperative physiotherapy
• Hyaluronic acid (Other): Regimen of intra-articular HA injections and postoperative physiotherapy

Primary outcomes

• International Knee Documentation Committee (IKDC) score [24 months]: Subjective IKDC core as a measure of joint function
• Knee injury and Osteoarthritis Outcome (KOOS) pain subdomain [24 months]: KOOS pain subdomain score as a measure of joint pain

Secondary outcomes

• Numeric Rating Scale (NRS) for pain [24 months]: Numeric Rating Scale (NRS) for pain

Other outcomes

• Incidence of Treatment-Emergent Adverse Events [Safety and Tolerability] [up to 24 months]

Sex: All, ages: 18 Years to 55 Years

Inclusion Criteria:

* Aged between 18 to 55 years at screening (20 to 57 years for the open-label extension)
* Present for evaluation and treatment of knee pain, knee swelling, or knee mechanical symptoms due to cartilage lesions
* Provide written informed consent
* International Cartilage Repair Society (ICRS) Grade 3 or 4 lesions diagnosis from MRI scans of the target knee
* All subjects must also satisfy at least 1 of the following inclusion criteria:

  * Isolated knee articular cartilage lesion (single lesion) estimated to be ≥3 cm2 as demonstrated on MRI scanning. Multiple knee articular cartilage lesions (multiple lesions) with at least 1 lesion estimated to be ≥3 cm2 as demonstrated on MRI scanning. Bipolar cartilage defects demonstrated on MRI scanning with at least 1 articular surface lesion to be ≥3 cm2. One or more cartilage defects involving the patello-femoral joint as demonstrated on MRI scanning with at least 1 lesion ≥3 cm2. One or more cartilage defects involving the tibio-femoral joint as demonstrated on MRI scanning with at least 1 lesion to be ≥3 cm2. Previously failed cartilage repair procedures (i.e., microfracture, osteochondral autograft transplantation surgery (OATS), ACI)

Exclusion Criteria:

* Three or more previous surgical interventions on the knee in question.
* Preoperative flexion deformity greater than 10 degrees.
* Presence of ligamentous injury which would require reconstruction, varus or valgus deformity requiring osteotomy, or cases that require complex surgery prior to cartilage regeneration