ChEMBL

On February 14, 2014, the FDA approved elosulfase alfa for the treatment of Mucopolysaccharidosis Type IVA (Morquio A syndrome). Elosulfase alfa is intended to replace the missing GALNS enzyme involved in an important metabolic pathway. Absence of this enzyme leads to problems with bone development, growth and mobility.

Mucopolysaccharidoses comprise a group of lysosomal storage disorders caused by the deficiency of
specific lysosomal enzymes required for the catabolism of glycosaminoglycans (GAG). Mucopolysaccharidosis IVA (MPS IVA, Morquio A Syndrome) is characterized by the absence or marked reduction in N-acetylgalactosamine-6-sulfatase activity. The sulfatase activity deficiency resultsin the accumulation of the GAG substrates, KS and C6S, in the lysosomal compartment of cells throughout the body. The accumulation leads to widespread cellular, tissue, and organ dysfunction. It is a rare autosomal recessive disease, affecting approximately 800 people in the US, and significantly shortens life expectancy, with most patients dying at an early age. Sulfonase alfa is the first approved treatment for Morquio A syndrome.

Elosulfase alfa is intended to provide the exogenous enzyme N-acetylgalactosamine-6-sulfatase that will be taken up into the lysosomes and increase the catabolism of the GAGs KS and C6S. Elosulfase alfa uptake by cells into lysosomes is mediated by the binding of mannose-6-phosphate-terminated oligosaccharide chains of elosulfase alfa to mannose-6-phosphate receptors.

N-acetylgalactosamine-6-sulfatase homodimer (from PDB 4FDI)