Xintela has completed its final 24-month analysis of the Phase I/IIa clinical study evaluating XSTEM for knee osteoarthritis. The company reports that patients who received the highest dose of XSTEM showed sustained improvements in knee pain, joint function, and structural integrity of bone and cartilage two years after a single injection. XSTEM is composed of allogeneic (donor-derived) integrin α10β1-selected mesenchymal stem cells and is both developed and manufactured by Xintela.
The study involved 24 patients, aged 41–75, with moderate knee osteoarthritis (Kellgren-Lawrence grade II-III). Participants were divided into three cohorts and treated with one of three dose levels (4, 8, or 16 million cells) via a single intra-articular injection. Patients in the highest dose group were followed for 24 months, while those in the lower dose groups completed 18 months of follow-up.
The primary focus was safety and tolerability, while secondary endpoints included efficacy measures such as pain reduction, improved joint function, and changes in cartilage and bone structure as assessed by patient-reported outcomes, X-ray, and MRI (magnetic resonance imaging).
Key results from the final analysis include:
* All dose levels of XSTEM were safe and well tolerated, with no serious treatment-related adverse events reported.
* Statistically significant and clinically meaningful improvements in knee pain and function were observed at all dose levels 18 months after treatment, with the highest dose group experiencing the most pronounced benefits.
* The highest dose group demonstrated sustained, significant improvements in all pain and function assessments (using VAS — Visual Analogue Scale — and KOOS — Knee injury and Osteoarthritis Outcome Score) from 1 month to 24 months post-treatment. Pain was reduced by 57% (VAS) at 24 months compared to baseline.
* Only the highest dose group showed improvement in subchondral bone structure and a trend toward halting cartilage breakdown, with these effects maintained at 24 months.
* Xintela concludes that XSTEM treatment was safe, led to sustained improvements in pain, function, and joint structure, and supports the potential for disease modification in osteoarthritis.
Lucienne Vonk, Chief Scientific Officer at Xintela, commented:
“We are very excited about the duration of the therapeutic effects of XSTEM. Patients in the study continued to experience relief from their symptoms for at least two years after a single XSTEM injection, which is notably longer that what is seen with other commonly used injection treatments, such as corticosteroids and hyaluronic acid, where effects often last between six weeks and six months. This beneficial effect of XSTEM could represent a meaningful improvement in the quality of life of osteoarthritis patients who are seriously affected by pain and immobility.
On top of this, we also see a disease-modifying potential of XSTEM. This means that XSTEM could halt and even reverse the disease by stopping the degradation of cartilage and other joint tissues, and by regenerating and repairing the damaged joint tissues. This could lead to a delay in and even reduced need for joint replacement surgery. The disease-modifying potential of XSTEM is especially promising for a large group of patients that are hampered in their daily lives by osteoarthritis but are still too young for a joint replacement and currently rely on therapies that manage their symptoms”.
The company notes that no disease-modifying osteoarthritis therapies are currently available, and states that XSTEM’s sustained effect and safety profile could make it an attractive candidate for further clinical development and potential partnership or licensing opportunities.
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