The general aim of the project is to develop a treatment for severe hoarseness due to vocal fold (VF) scarring. Vocal fold scarring can be caused by tumor surgery, radiotherapy, severe inflammation or is early acquired (sulcus vocalis with scar) and results in stiff vocal folds with decreased vibratory capacity and severe deterioration or total loss of voice (aphonia). There is no lasting effective treatment. Bone marrow derived mesenchymal stem cells (MSC) are immunomodulatory, decrease inflammation and improve endogenous healing. After receiving ethical permission the investigators have since 2012 treated 16 patients with manifest vocal fold scarring and severe hoarseness by scar resection and local injection of autologous bone marrow MSC to restore speech. This project was the first in the world to study the effects of MSC treatment of vocal fold scarring in humans. Analysis was made before and up to 12 months post operatively with voice recordings, examination with high speed camera and elasticity measurements of the vocal folds with novel technology. No side effects were found for any patient and for two thirds of the patients with 12 months follow-up the vocal fold function improved and no patient deteriorated.

While cell therapy with autologous MSC was classified according to the Tissue Legislation before 2015, it is now regarded as drug treatment. In accordance with this legislation, the MSC production is now full scale GMP. The investigators have recently received permissions from Swedish Medical Product Agency (DNr 5.1-2019-92069) and from the Regional ethic committee (Drn 2019-06160) for an open Phase I/Il study in patients with severe dysphonia and vocal fold scarring to evaluate safety, tolerability and vocal function after surgery with local administration of autologous mesenchymal stromal cell product KI-MSC-PL-204 as an extended study on 15 patients.

MSC may in the future be used to treat patients with severe hoarseness due to scarring, as well as other damages in the airways.