This study is a randomized, double-blind, multicenter Phase II/III clinical trial designed to evaluate the effectiveness and safety of umbilical cord-derived mesenchymal stem cell (UC-MSC) secretome compared with sodium hyaluronate in patients with knee osteoarthritis. Knee osteoarthritis is a common degenerative joint disease that causes chronic pain and functional limitation. Participants will be randomly assigned to receive intra-articular injections of either UC-MSC-derived secretome or sodium hyaluronate. The study aims to assess improvements in knee pain, physical function, and overall clinical outcomes, as well as to evaluate the safety of the interventions over the study period.

This multicenter, randomized, double-blind Phase II/III clinical study aims to compare the efficacy and safety of intra-articular UC-MSC-derived secretome with sodium hyaluronate in patients with Kellgren-Lawrence grade 2-3 knee osteoarthritis. Eligible participants will be randomly allocated to one of two treatment arms. Clinical outcomes will be evaluated using validated pain and functional assessment tools at predefined time points. Safety assessments will include monitoring of adverse events throughout the study period. The results of this study are expected to provide evidence regarding the potential role of UC-MSC-derived secretome as an alternative therapeutic option for knee osteoarthritis.

Inclusion Criteria:

1. Diagnosed with primary OA in one or both knees based on American College of Rheumatology (Clinical and Rheumatology criteria). If both knees have OA, the knee with the OA grade that falls within the inclusion criteria (grade 2-3) will be selected. If both knees meet the inclusion criteria, the knee with the highest grade and the one that is most uncomfortable will be chosen.
2. Males or females in the age range 40-70 years
3. Symptomatic knee OA (defined by pain at the affected joint for at least 3 months before inclusion and visual analog scale 40 - 70 mm on a 100 mm Visual Analog Scale (VAS).
4. Radiographic evidence of grade 2 to 3 osteoarthritis (OA) based on Kellgren and Lawrence radiographic criteria.
5. Body mass index between 18 - 30 kg/m2
6. Female participants of childbearing age who agreed to use accepted methods of contraception during the course of the study.
7. Ability to provide written informed consent and willing to participate the study

Exclusion Criteria:

1. Participants who, based on physical examination and clinical history (anamnesis), are in the active or acute phase of cardiac, pulmonary, hematological, hepatic, renal, systemic autoimmune, immunodeficiency, or coagulation disorders that may interfere with the administration of the study drug (Secretome or Sodium Hyaluronate) will be excluded,
2. Diagnosed with a meniscal rupture based on clinical history (anamnesis) and physical examination. If the anamnesis and physical examination show symptoms and signs of a meniscal rupture, further evaluation will be performed using ultrasound (USG),
3. Participants with significant axial deviation, defined by valgus or varus deformity observed during physical examination, will be excluded,
4. Participants with other pathological lesions on knee X-rays from the screening examination will also be excluded,
5. History of any form of secondary arthritis in the knee due to trauma,
6. History of surgery or major trauma to the knee joint
7. Has knee effusion,
8. Has any other inflammatory disorder of the knee joint
9. Diagnosed with active malignancy.
10. History of stem cell or secretome therapy.
11. Intra-articular injection of corticosteroid and/or prior treatment with Sodium Hyaluronate and/or platelet rich plasma (PRP) in past 3 months.
12. Use of NSAIDs and/or chondroprotective supplements, such as glucosamine and chondroitin sulfate, within 7 days before the trial, whether used orally, topically, or via injection,
13. Undergoing immunosuppressive therapy, or anticoagulant therapy, or corticosteroid therapy.
14. For women of child-bearing potential: positive pregnancy test or lactating (females who were planning pregnancy within the next year were excluded).
15. Enrolled in any other clinical trials within the past four weeks.
16. The principal investigator considers that the participant is ineligible for the clinical trial due to any reasons other than those listed above

De-identified individual participant data underlying the primary and secondary outcome measures, including demographic characteristics, baseline clinical data, outcome scores, and adverse event data, will be shared. All data will be fully anonymized, with no direct identifiers, in accordance with applicable ethical and regulatory requirements.

De-identified individual participant data and supporting documents will be available beginning 6 months after publication of the primary study results and will remain available for up to 5 years.

Access to de-identified IPD will be granted to qualified researchers who submit a methodologically sound research proposal. Requests will be reviewed by the study steering committee. Data will be shared under a data use agreement to ensure participant confidentiality and appropriate use of the data.

Participants and investigators will be blinded to treatment allocation. UC-MSC-derived secretome and sodium hyaluronate will be prepared and administered in a similar manner to ensure blinding is maintained during the study period.