Libmeldy is a medicine used to treat children with metachromatic leukodystrophy (MLD). MLD is a rare inherited disorder in which there is a change (mutation) in a gene needed to make an enzyme called arylsulfatase A (ARSA), which breaks down substances called sulfatides. As a result, sulfatides build up and damage the nervous system and other organs, causing symptoms such as walking difficulties, gradual mental deterioration and eventual death.

Libmeldy is used in children with MLD who have mutations in the ARSA gene. It is given to

• those with late infantile or early juvenile forms of the disease who have not yet developed symptoms;
• those with early juvenile MLD who have initial symptoms but can still walk independently and have not yet developed mental deterioration.

Libmeldy is a type of advanced therapy medicine called a ‘gene therapy’. This type of medicine works by delivering genes into the body. The active substance in Libmeldy is stem cells, (CD34+ cells), derived from the patient’s own bone marrow or blood, that have been modified to contain a copy of the gene to make ARSA and can divide to produce other sorts of blood cells.

MLD is rare, and Libmeldy was designated an ‘orphan medicine’ (a medicine used in rare diseases) on 13 April 2007.