Stem Cell Therapy for Stress Urinary Incontinence: Why Has Clinical Success Remained Limited?

INTRODUCTION AND HYPOTHESIS: Stem cell therapy for stress urinary incontinence (SUI) has been pursued for more than a decade, supported by a compelling regenerative rationale and reassuring early-phase safety data. Yet clinical efficacy has remained modest, complete continence uncommon, and durability uncertain. METHOD: In this Clinical Opinion, we argue that translation has stalled for reasons that are both biological and conceptual: heterogeneous cell products and manufacturing variability undermine reproducibility; endpoints and follow-up are insufficiently harmonized to benchmark against surgical standards; chronically fibrotic periurethral tissue may be biologically quiescent and poorly permissive for regenerative activation; and, fundamentally, continence is a biomechanical phenomenon that cell injections alone cannot replicate. RESULTS: We propose that future progress will depend on validated potency assays, mechanism-driven trial design, microenvironment priming strategies, and integration of regenerative biology with biomechanical reinforcement (e.g., scaffolds or biologically enhanced support constructs). CONCLUSION: Until such integration occurs, stem cell therapy for SUI should remain investigational.