Treatment of vocal fold scarring with autologous bone marrow-derived human mesenchymal stromal cells—first phase I/II human clinical study

Abstract

Vocal fold (VF) scarring, caused by surgery or inflammation, often results in severe voice problems or aphonia. Effective lasting treatment is lacking. Previous in vitro and in vivo animal studies reported positive effects on VF scar resolution with mesenchymal stromal cell (MSC) implantation. The principal aim of this study was to examine safety aspects and secondly treatment efficacy vocal fold function in patients with VF scarring and severe voice problems. In this open-label phase I/II study, 16 patients were treated with surgical scar resection followed by injection of autologous MSCs (0.5–2 × 10⁶ MSCs/patient). Patients were monitored 1 year for serious adverse events (SAE) or minor complications. Therapeutic efficacy on treated VFs was evaluated by measurement of VF vibrations using high-speed laryngoscopy (HSL) and phonation pressure threshold (PTP) for elasticity and VF function. Patients self-reported voice change using the Voice Handicap Index (VHI). No SAE or minor side effects were reported. Video ratings of VF vibrations and digitized analysis of HSL and PTP were significantly improved for 62–75% of the patients (depending on parameter). Two patients showed deteriorated VF vibrations, but improved PTP. VHI was significantly improved in 8 patients, with the remaining experiencing no significant change. The results indicate that local injection of autologous MSC into scarred VFs with severe voice problems may offer a safe and feasible therapeutic option. VF vibration and elasticity were improved in approximately two thirds of treated patients. This clinical study is registered in clinicaltrials.gov (ID: NCT01981330). Retrospective registration of first patient (20130511). https//: register.clinicaltrials.gov/.