A Study to Investigate the Effectiveness, Safety, and Tolerability of MAG200 Solution for Intra-articular Injection Compared With Placebo in Participants Aged 35 to 75 Years of Age With Symptomatic Osteoarthritis of the Knee.

Inclusion Criteria 1. Males and females aged ≥ 35 years to ≤ 75 years inclusive. 2. BMI ≥ 19.0 to ≤ 35.0 kg/m2. 3. Documented clinical diagnosis of OA of the study knee. 4. Documented radiological grading of Grade 2 or Grade 3 medial and/or lateral compartment OA of the study knee. 5. Documented radiological grading of OARSI JSN 1-2 of the medial and/or lateral compartment of the study knee. 6. Primary OA treatment of the study knee already attempted within the last 12 months, defined as: 1. Prescribed analgesia/anti-inflammatory medication where appropriate, AND 2. an attempted exercise program prescribed by a physical therapist (e.g., physiotherapist, osteopath) or medical practitioner for at least 8 weeks, AND 3. weight management, where appropriate. 7. Moderate to severe knee specific activity related pain score on the NRS for Pain over the past week. 8. Moderate to severe knee specific functional limitation on KOOS-PS. 9. Less than 5 degrees varus or valgus knee deformity of the study knee relative to neutral alignment. Exclusion Criteria 1. Any of the following relating to the study knee: 1. Radiological evidence of KL Grade 4 OA (involving medial, lateral and/or patellofemoral compartment) or OARSI JSN 3. 2. History of recurrent mechanical instability and / or locking. 3. Joint surgery or significant knee injury within 12 months prior to Day 1. 4. Metal in-situ resulting in metal artefact which impacts/prevents MRI assessment. 5. MRI confirmed: i. Generalised full thickness chondral loss involving tibial and/or femoral weight bearing surfaces ii. Total meniscectomy iii. Complete posterior meniscal root tear iv. Subchondral insufficiency fracture v. Osteonecrosis vi. Malignant bone marrow infiltration vii. Solid tumors viii. Traumatic fracture/bone contusion ix. Knee pathology requiring orthopaedic assessment/intervention (e.g., significant loose body) 2. Other causes of the knee symptoms unrelated to knee OA. 3. Significant and debilitating OA in the non-study knee.