An open phase I/IIa study evaluating safety, patient-reported outcomes and voice function after surgery, local administration of mesenchymal stromal cells and voice training in patients with vocal fold scarring and dysphonia

• This phase I/IIa trial demonstrates that autologous bone marrow-derived MSC injection combined with surgical scar resection and voice training is safe and feasible for patients with vocal fold scarring and severe dysphonia, with no serious adverse events reported up to 36 months. • The study proposes a structured post-operative voice training protocol, addressing a gap in previous MSC trials where voice training was not standardized or documented. • Preliminary efficacy outcomes suggest improvements in vocal fold function and patient-reported voice-related quality of life, supporting the potential of MSC therapy as a regenerative treatment for vocal fold scarring. • The predefined clinically relevant changes and comprehensive assessment battery provide a robust framework for future larger-scale trials in this patient population.