Inclusion criteria:
1. Willing and able to provide informed consent;
2. Male or female participants aged ≥40 years;
3. Evidence of OA in the medial tibiofemoral joint (MTJ) as follows:
* Clinical - knee pain;
* Radiological - Kellgren-Lawrence:
1. Grade 2 - definite osteophytes, possible joint space narrowing (JSN), or;
2. Grade 3 - moderate osteophytes, definite JSN, some sclerosis, possible bone-end deformity (Altman et al., 1986; Kellgren et al., 1957; Kohn et al., 2016).
3. Minimal joint space width (JSW) of 2.5 mm on knee X-ray (OARSI 1 or 2);
4. Score ≥3 on visual analogue scale (VAS) (0-10 range) for pain at Screening.
Exclusion Criteria:
1. Grade 0, 1 or 4 on the Kellgren-Lawrence grading scale for the target knee:
* Grade 0: No osteophyte or JSN;
* Grade 1: Doubtful JSN and possible osteophytic lipping;
* Grade 4: Large osteophytes, 'bone-on-bone' JSN, severe sclerosis, and definite deformity of bone ends;
2. Severe malalignment of \>10° varus or valgus.
3. OA secondary to joint dysplasia, aseptic osteonecrosis, acromegaly, Paget's disease, Ehlers-Danlos Syndrome, Gaucher's disease, Stickler's syndrome, joint infection, haemophilia, haemochromatosis, calcium pyrophosphate deposition disease, neuropathic arthropathy, trauma, rheumatoid arthritis, gout, psoriatic arthritis, autoimmune arthritis or spondylitis;
4. Receipt of any investigational medicinal product (IMP) or any experimental therapeutic procedure in the 3 months or 5 half-lives before Screening, whichever is longer;
5. Taking corticosteroids or any immunosuppressants, e.g., cyclosporine, prior to Screening;
6. IA treatment with steroids or hyaluronic acid derivatives in the 3 months before Day 1;
7. Planned major surgery, e.g., joint replacement, within 2 months after IA injection;
8. Previous surgery on the target knee including diagnostic arthroscopy;
9. Lesions at the planned injection site that would present a contraindication to local injection of the study drug, e.g., open wounds, psoriatic lesions or infections of the skin;
10. Any known active infection;
11. Clinically significant abnormal haematology or biochemistry values (platelets, haemoglobin, white blood cells, alkaline phosphatase, AST, ALT, blood creatinine, bilirubin) or coagulation (PT, PTT) at Screening;
12. Positive result for HTLV, HIV, Hepatitis B or C;
13. Hypersensitivity to any of the IMP components or excipients;
14. History of sarcoma;
15. History of cancer within five years, except treated basal cell and squamous cell carcinoma of the skin;
16. Women of child-bearing potential, i.e., not post-menopausal (see Section 8.4.5)
17. Women who are pregnant or breastfeeding;
18. Current drug or alcohol abuse;
19. Contraindication to receiving a gadolinium contrast-enhanced magnetic resonance imaging (MRI) of the target knee (metallic implants, claustrophobia, previous anaphylactic reaction to gadolinium, eGFR1 \<30 mL/min/1.73 m2, acutely deteriorating renal function) or is unwilling to have MRI performed;
20. Participants with subchondral insufficiency fracture, osteonecrosis, acute or subacute fracture, acute bone contusion, pathologic fracture, stress fracture, fragmentation of articular bone, bone or soft tissue tumour, bone marrow infiltration, posterior meniscal root tear, rheumatoid arthritis, gout based on X-ray or MRI reading;
21. Participants who, in the Investigator's opinion, are unsuitable or unlikely to comply with the study procedures.
