Supporting the Immune System After Transplantation
Graft-versus-host disease (GVHD) is a complication that can occur after a donor stem cell transplant. It develops when donated immune cells begin attacking the recipient’s tissues, creating inflammation that may affect areas such as the skin, liver, and digestive system.
When the condition does not respond adequately to corticosteroids, researchers continue to explore additional ways to help regulate the immune response and support damaged tissues.
A 2024 Phase II clinical trial investigated whether human umbilical cord-derived mesenchymal stem cells (UC-MSCs) could provide additional support when combined with standard second-line treatment.
A Stronger Clinical Trial Design
The study included 78 patients across seven medical centers. Participants were randomly assigned to receive either UC-MSCs or a placebo alongside an existing second-line therapy.
Patients in the MSC group received intravenous infusions of 1 million UC-MSCs per kilogram of body weight twice weekly. Most received at least eight infusions over four weeks, while some partial responders continued treatment for another four weeks.
Because the study was both randomized and double-blind, neither the participants nor the treating teams knew who was receiving the MSC treatment or placebo during the trial. This helped researchers make a more controlled comparison between the two groups.
Encouraging Responses After a Full Treatment Course
When researchers analyzed all 78 participants, the overall response rate at day 28 was 60% in the UC-MSC group compared with 50% in the control group. Although this difference favored MSC treatment, it was not statistically significant.
However, a more encouraging result appeared among the 62 patients who completed at least eight infusions.
In this group:
- 71.9% of UC-MSC-treated patients responded by day 28, compared with 46.7% in the control group.
- Among patients whose GVHD involved the digestive system, response rates were 66.7% with UC-MSCs versus 33.3% with placebo.
- Patients receiving UC-MSCs had a median response time of approximately 14 days.
These findings led researchers to suggest that the effects of UC-MSC therapy may develop gradually and that completing the planned treatment course could be important when evaluating its potential benefits.
Why UC-MSCs Are Being Studied
Rather than simply replacing damaged cells, MSCs are being investigated largely for the biological signals they release and the way they interact with the immune system.
In GVHD, this is particularly relevant because excessive immune activity can lead to inflammation and tissue injury. UC-MSCs may help create a more balanced environment by influencing inflammatory and immune responses while supporting the repair of affected tissues.
The study’s findings were especially interesting in patients with gastrointestinal involvement, where controlling inflammation and supporting tissue recovery can be particularly challenging.
A Reassuring Safety Profile
Safety findings were also encouraging and serious adverse events occurred at similar rates in the UC-MSC and placebo groups, and investigators did not attribute any serious adverse events to the study treatments.
Researchers also reported:
- No infusion-related toxicity
- No secondary malignant disease during follow-up
- Similar overall adverse-event rates between the UC-MSC and control groups
These results suggest that repeated intravenous UC-MSC administration was generally well tolerated within this clinical setting.
Building the Evidence for UC-MSC Therapy
This study adds valuable clinical evidence to the growing research surrounding umbilical cord-derived MSCs and immune-related conditions.
While the primary analysis involving all participants did not show a statistically significant advantage over placebo, patients who completed at least eight infusions experienced a significantly higher response rate, with particularly encouraging results among those with gastrointestinal involvement.
Combined with the favorable safety findings, the results support continued research into how UC-MSCs may help regulate excessive immune activity and support tissue recovery following transplantation.
Larger studies may help researchers better identify which patients are most likely to benefit and determine how UC-MSC therapy can best be incorporated into future treatment strategies.
Source
Jiang E, Qian K, et al. Efficacy and safety of human umbilical cord-derived mesenchymal stem cells versus placebo added to second-line therapy in patients with steroid-refractory acute graft-versus-host disease: a multicentre, randomized, double-blind, phase 2 trial. BMC Medicine. 2024;22:555. doi: 10.1186/s12916-024-03782-5. PMID: 39587570; PMCID: PMC11590523. Available from: https://pmc.ncbi.nlm.nih.gov/articles/PMC11590523/
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