Nature Cell Reports 5-Year Long-Term Follow-Up Results of JointStem
Sustained Pain Relief and Functional Improvement Observed Without Surgical Intervention
Significant Inhibition in Progression to Total Knee Arthroplasty Over Five Years
LOS ANGELES, CA / ACCESS Newswire / December 16, 2025 / Nature Cell Co., Ltd., a biopharmaceutical company specializing in adult stem cell-based therapies (Chairman: Jeong-Chan Ra), announced the results of a long-term follow-up study tracking patients for up to five years who participated in the Korean Phase 3 clinical trial of JointStem, an investigational stem cell therapy for severe knee osteoarthritis.
This long-term follow-up study assessed long-term outcomes following a single intra-articular injection of JointStem, including changes in pain, improvements in joint function, conversion to total knee arthroplasty (TKA), patient treatment satisfaction, and long-term safety. The findings provide clinically meaningful evidence supporting the long-term therapeutic effects of stem cell-based treatment.
The study population consisted of patients with severe knee osteoarthritis who had exhausted conventional treatment options, including nonsteroidal anti-inflammatory drugs (NSAIDs), hyaluronic acid injections, and corticosteroid injections, and for whom further clinical improvement was considered unlikely. At baseline, these patients exhibited significant pain and functional impairment.
Following a single administration of JointStem, statistically significant reductions in pain scores-measured by WOMAC pain and VAS-were observed at six months post-treatment compared with baseline. Measures of joint function also demonstrated statistically significant improvement.
These clinical benefits were generally maintained at 1, 3, and 5 years after treatment, with no evidence of abrupt loss of efficacy or clinically relevant throughout the observation period.
During the five-year observation period, 94.23% of patients did not undergo total knee arthroplasty, confirming the preventive and suppressive effect of JointStem on progression to surgical intervention. Among the small number of patients who did eventually undergo TKA, the average time to conversion was 40.5 months, indicating a meaningful delay in the need for surgery even in a severe patient population.
Patient-reported treatment satisfaction was also high, with 82.96% of respondents indicating that the treatment met their expectations and reporting "satisfied" or "very satisfied." A similarly high proportion of patients indicated they would choose the same treatment again and would recommend it to others, reflecting substantial improvements in perceived quality of life.
Over the five-year follow-up period, no treatment-related serious adverse events were reported, and no new safety signals were identified, demonstrating that JointStem can be used safely over the long term.
Dr. Jeong-Chan Ra, Chairman and Head of Research and Development at Nature Cell, stated, "The statistically significant improvement in pain and joint function observed as early as six months after a single injection-and the fact that these effects were maintained for five years in patients with severe knee osteoarthritis who had limited treatment options-is clinically highly meaningful. These long-term follow-up data not only underscore the therapeutic value of JointStem but may also serve as important scientific evidence to support regulatory approval by the U.S. Food and Drug Administration."
For inquiries, please contact:
Email: janeshin@stemcellbio.com
SOURCE: Nature Cell
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