Multicenter, Randomized, Open-Label, Standard Treatment-Controlled Parallel Group Phase 2 Study to Evaluate Efficacy and Safety of Intra-Articular Injections of Autologous Peripheral Blood Stem Cells and Hyaluronic Acid Adjuvant Therapy Following Subchondral Drilling Surgery for the Treatment of Articular Cartilage Injury in the Knee With an Optional Open-Label Extension for the Standard Treatment-Controlled Group

Study start date: December 1, 2015

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