MSC Cell Therapy Shows Safety and Immune Benefits in Advanced Liver Cirrhosis
Phase Ia/Ib dose-escalation trials reveal MSC therapy is safe in decompensated liver cirrhosis, with higher doses producing stronger immune rebalancing effects.
Summary
Researchers conducted sequential Phase Ia and Ib clinical trials testing escalating doses of mesenchymal stromal cell (MSC) therapy in 24 patients with decompensated liver cirrhosis (DLC). Single doses ranging from 50 million to 200 million cells were tested in Phase Ia, followed by three-dose regimens in Phase Ib. No severe adverse events or dose-limiting toxicities occurred through 28-day follow-up. Multi-omics analyses — including single-cell RNA sequencing and mass cytometry — revealed dose-dependent immune modulation, particularly involving a novel monocyte subset called MX1+ monocytes. Higher doses and multiple-dose regimens showed preliminary improvements in liver function scores and quality of life, providing the first human evidence of a dose-response relationship for MSC immunomodulation in DLC.
Detailed Summary
Decompensated liver cirrhosis (DLC) represents a major unmet medical need, characterized by progressive liver failure, systemic inflammation, and paradoxical immune deficiency collectively termed cirrhosis-associated immune dysfunction (CAID). Liver transplantation remains the only cure, but donor shortages and high costs make it inaccessible for most patients. Mesenchymal stromal cell (MSC) therapy has emerged as a candidate treatment due to its immunomodulatory properties, but optimal dosing strategies and mechanistic evidence from human trials have been lacking.
This study conducted two sequential single-arm dose-escalation Phase I trials (Phase Ia: NCT05227846; Phase Ib: NCT05984303) enrolling 24 DLC patients between March 2022 and March 2024. Phase Ia tested single infusions across four cohorts at doses of 5.0×10⁷, 1.0×10⁸, 1.5×10⁸, and 2.0×10⁸ cells using a 3+3 design with follow-up at Days 3, 7, 14, and 28. Phase Ib then tested two cohorts receiving three weekly doses at 1.0×10⁸ or 2.0×10⁸ cells per infusion. Patients had a median MELD score of 12.38 and Child-Pugh score of 8.12, with leading etiologies of HBV infection and alcohol use.
MSC therapy demonstrated a strong safety profile: no severe adverse events, dose-limiting toxicities, or serious unexpected adverse reactions were observed in either phase through Day 28. The only notable event was a Grade 1 rash in one patient that prompted additional enrollment in one cohort per protocol. Multi-omics analyses — integrating single-cell RNA sequencing and cytometry by time of flight (CyTOF) — revealed that higher MSC doses produced stronger and more consistent immunomodulatory effects. A critical finding was the identification of MX1+ (myxovirus resistance 1-positive) monocytes as a key mediator of MSC-induced immune modulation. These cells showed dose-dependent changes in abundance and function, with effects sustained for up to seven days post-treatment but diminishing by Day 14, providing mechanistic rationale for weekly dosing intervals.
Preliminary clinical signals showed improvements in Child-Pugh scores, MELD scores, liver function biomarkers, and quality-of-life metrics, with the most notable trends in the higher-dose (2.0×10⁸) and multiple-dose cohorts. These early signals, while not powered for efficacy, suggest that both dose intensity and repetition matter for therapeutic outcomes.
This work provides the first systematic human-based evidence of a dose-response relationship for MSC immunomodulation in DLC, offering a scientific basis for designing larger efficacy trials. The identification of MX1+ monocytes as a pharmacodynamic biomarker and mechanistic mediator is a novel contribution that could inform both patient stratification and treatment monitoring in future studies.
Key Findings
- No severe adverse events or dose-limiting toxicities observed across all doses up to 2.0×10⁸ cells through 28 days.
- Higher MSC doses produced stronger immune modulation, particularly affecting monocyte subsets in a dose-dependent manner.
- MX1+ monocytes identified for the first time as a key mediator of MSC-induced immunomodulation in human DLC patients.
- Immunomodulatory effects peaked within 7 days post-infusion but waned by Day 14, supporting weekly dosing intervals.
- Higher-dose and multiple-dose regimens showed preliminary improvements in MELD scores, Child-Pugh scores, and quality of life.
Methodology
Sequential single-arm Phase Ia (n=15, single dose, 4 cohorts: 5×10⁷–2×10⁸ cells) and Phase Ib (n=9, three weekly doses, 2 cohorts) dose-escalation trials using a 3+3 design. Multi-omics mechanistic analyses included single-cell RNA sequencing and CyTOF mass cytometry on peripheral blood samples collected at multiple timepoints through Day 28.
Study Limitations
The trials were small (n=24 total), uncontrolled, and powered for safety rather than efficacy, so clinical benefit signals are preliminary and must be interpreted cautiously. Follow-up was limited to 28 days, leaving longer-term safety and durability of response unknown. The patient population was heterogeneous in etiology and disease severity, which may limit generalizability.
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