Clinical trial of gene therapy for MPS VI - a severe lysosomal storage disorder

Mucopolysaccharidosis VI (MPS VI, or Maroteaux-Lamy syndrome; OMIM #253200) is a rare lysosomal storage disease caused by deficient activity of arylsulfatase B (ARSB). MPS VI is characterized by growth retardation, corneal clouding, cardiac valve disease, organomegaly, skeletal dysplasia, without central nervous system involvement. Thus, systemic therapies targeting peripheral organs have the potential to fully correct the MPS VI phenotype. Enzyme replacement therapy, the current treatment for MPS VI, requires weekly infusions of a costly enzyme and has limited efficacy on bone and corneal disease. Based on the encouraging preclinical results generated by our group, gene therapy based on a single intravascular administration of adeno-associated viral (AAV) vectors targeting liver has the potential to provide a lifelong source of ARSB.
The MeuSIX consortium plans to conduct a multicenter phase 1/2 clinical trial to investigate the safety and efficacy of AAV-mediated gene therapy in patients with MPS VI. An orphan drug designation (ODD) has been obtained from both the European Medicinal Agency and the US Food and Drug Administration for the MPS VI therapeutic AAV vector. The results from this clinical trial proposed by the MeuSIX consortium has the potential to have a tremendous impact on the natural history of MPSVI and to significantly improve the quality of life of the affected patients. Moreover, the approach developed may facilitate the development of similar approaches for other inborn errors of metabolism.