sAfety PerfoRmance chitOsan osteOarthritis ViscosupplEmentation

Inclusion Criteria: * Male or female with age ≥ 40 years and ≤ 85 years except in Stage 1 cohort where age is limited to ≤ 70 years. * Body mass index (BMI) ≤ 35 kg/m². * Uni- or bilateral femorotibial knee OA associated or not with femoropatellar knee OA. * Primary knee osteoarthritis responding to the clinical and radiological criteria of the American College of Rheumatology (ACR) * Radiological Kellgren and Lawrence (K\&L) grade II to III from a standing knee radiograph taken less than 6 months previously. * Symptomatic pain at least 6 months in the treatment knee not or poorly responding to first line non-opioid analgesics and non-steroidal anti-inflammatory drug in oral uptake. * Pain criteria assessed prior to injection at visit 1 after mandatory 48-hour wash-out: * Treatment knee: 7-17 points of the 5-graded Likert WOMAC pain score and at least 2 points on the WOMAC pain subscore A1 in the most affected knee. * Non-treatment knee: not more than 6 points of the 5-graded Likert WOMAC pain score in the contralateral knee. * Fully ambulatory patient for functional evaluation * Willing NOT to take any pain medication for 48 hours prior to study visit. * For female NOT surgically sterile (tubal ligation or hysterectomy) or NOT postmenopausal for at least one year, must have an effective contraception (pill, patch, ring, diaphragm, implant and intrauterine device). * Able to understand and follow the instructions of the study. * Having signed a written informed consent. Exclusion Criteria: * Related to the OA pathology and related symptoms: * Radiological K\&L grade 0, I or IV from a standing knee radiograph taken less than 6 months previously. * Exclusively patellofemoral osteoarthritis where the symptoms, including pain, are principally of patellofemoral origin (Patellar syndrome). * Chondromatosis or villonodular synovitis of the knee. * Clinically-apparent knee effusion, inflammation or flare-up of the knee or abnormal synovial fluid macroscopy or volume upon arthrocentesis on the day of injection. * History of injury to the treatment knee during the 6 months before inclusion or recent trauma (\<1 month) of the knee responsible of pain that is not directly related to OA symptoms. * Significant clinically-assessed or radiographic varus or valgus deformation of the selected knee at the judgment of the investigator. * Inflammatory disease. * Pathologies interfering with the evaluation of OA pain for the knee to be treated. * Related to treatments: * Contraindications: hypersensitivity or allergy to the product components of KIO014, including chitosan, sorbitol and/or other mushroom-derived products, or to hyaluronic acid-based products. * Corticosteroids or Plasma Rich Platelet (PRP) or cell-based therapy injection in the treatment knee in the last 3 months before injection. * Hyaluronic acid injection in the treatment knee in the last 6 months before injection. * Arthroscopy and surgery in the treatment knee in the last 6 months before injection. * Oral corticotherapy ≥5 mg/day (in prednisone equivalent) in the last 3 months before injection. * Change in the dosage regimen of symptomatic slow-acting drugs (SYSAD) or dietary supplement in the last 3 months before injection. * Change in physiotherapy of the treatment knee in the last 3 months. * Anticipated need for any surgical or other invasive procedure during the trial including prosthesis in the treatment knee. * Anticipated need for any forbidden OA treatments during the trial except for rescue treatment as defined in the study protocol. * Anticoagulants: coumarin-based compounds or heparin. * Related to associated diseases: * Any Investigator-assessed clinically significant condition that may represent a substantial risk to the patient or may have an impact on the study assessments. * History of recurrent bacterial infection, defined as at least 3 major infections resulting in hospitalization and/or requiring intravenous antibiotic treatment within the past 2 years or history of synovial infection or infections or skin diseases in the area of the injection site. * History of symptomatic hip OA * History of autoimmune disease. * Severe, ongoing and uncontrolled diseases, or other major disease, or other severe uncontrolled conditions. * Subject addicted to alcohol or drugs or ongoing or recently recovered depression or psychiatric disorders or any other disorder and/or that may pose a health risk to the subject in the study and/or may have an impact on the study assessments. * Severe alteration of mobility preventing any functional evaluation. * High risk of hemorrhage. * Related to patients: * Participation in a therapeutic clinical trial in the last 3 months before injection. * Patient under guardianship or judicial protection. * Pregnancy, breastfeeding, planned conception, or premenopausal women without effective contraception, tubal ligation or hysterectomy.