This clinical study is to investigate the safety and efficacy of NCR100 injection in subjects with knee osteoarthritis (KOA). It contains two parts dose-escalating, and blind random study in adult KOA subjects.

Knee osteoarthritis(KOA) is a kind of degenerative joint disease characterized by chronic inflammation loss of articular cartilage and subchondral bone remodeling.In China, the estimated number of patients diagnosed with KOA reached 37.35millon. The aim of this sudy is to evaluate the safety tolerability and efficacy of human pluripotent stem cell derived mesenchymal stromal cells (NCR100) injection in the treatment of subjects with knee osteoarthritis.

Inclusion Criteria:

• Subjects who understand and voluntarily sign the Informed Consent Form（ICF） before the enrolment;
• Age: 40-65 years old, both genders;
• Diagnosis of knee osteoarthritis based on American College of Rheumatology criteria;
• Subjects with KOA who have persistent pain for more than six months
• Kellgren-Lawrence grade: II-III

Exclusion Criteria:

• Subjects previously diagnosed of secondary knee osteoarthritis, or those diagnosed with hip/ankle joint disease requiring medical intervention;
• Suffering from other diseases that impair knee function or joints;
• Have received stem cell therapy;
• Have knee injury history;
• Experienced knee surgery, or plan to undergo knee surgery;
• Received analgesics to relieve pain before Investigational Medicinal Product(IMP) injections;
• Have used traditional Chinese medicine to treat KOA within 4 weeks;
• Have used intra-articular injection of drugs to treat KOA within 12 weeks;
• Received glucosamine,chondroitin sulfate, or diacetate therapy before investigational drug intervention within 12 weeks;
• Subjects with acute phase of knee osteoarthritis;
• Severe deformity of the knee;
• Known or suspected allergy or a history of allergies;
• Abnormal results of laboratory examination as follows: Hepatic Insufficiency （Alanine Aminotransferase>2xULN or Aspartate aminotransferase [ast]>2xULN) renal dysfunction (creatinine clearance rate ≤60ml/min or blood urea nitrogen(BUN) > 2× ULN), Coagulation Defects (INR > 1.5) or severe hematological diseases (Grade 3 or above anemia [Hb < 8 g/dL], Grade 2 or above thrombocytopenia platelet count(PLT) < 75×10^9/L) ;
• BMI≥30kg/m^2
• Severe systemic infection or local knee joint infection;
• Have received systemic glucocorticoid therapy before intervention or need to take systemic glucocorticoid therapy during the treatment;
• Have a history of acute myocardial infarction or severe heart diseases,QT prolongation;
• Subjects with peripheral or central nervous system disorders that may interfere assessments;
• Have contraindications to Magnetic Resonance Imaging(MRI)
• Subjects who are unable to walk on his own;
• Subjects with alcohol/drug addiction/abuse or mental disorders;
• Pregnant or lactating, or unable to comply with contraceptives within 6 months after end of study;
• Have participated in other clinical trials within 12 weeks before the screening;
• Severe and poorly controlled comorbidities;