Drug portfolio for mucopolysaccharidoses
BioMarin (BMRN) holds three drugs in its portfolio indicated for different types of mucopolysaccharidoses, or MPS, disorders. The portfolio includes Vimizim (or elosulfase alpha) for MPS IV A, Naglazyme (or galsulfase) for MPS VI, and Aldurazyme (or laronidase) for MPS I. Incidence for MPS VI is around one in every 250,000–600,000 births. Incidence for severe MPS I is around one in every 100,000 births whereas MPS IVA incidence is around 1 in every 200,000–300,000 births. Overall, the prevalence of MPS is about one in every 25,000 births.
The above screenshot presents the odds of passing on the MPS I gene. When both parents are carriers, the probability of the child developing MPS I is 0.25.
Brief on mucopolysaccharidoses disorders
A group of inherited lysosomal storage disorders (or LSDs) is called as Mucopolysaccharidoses. Lysosomes are primary digestive units in the cells containing enzymes. The breaking down and digestion of particular nutrients such as carbohydrates and fats takes place inside lysosomes.
Mucopolysaccharide is composed of the words “muco,” “poly,” and “saccharide.” The first stands for thick mucus whereas the last means sugar. “Poly” is a general term for many. So, mucopolysaccharides are nothing but long chains of sugar molecules. These molecules are called glycosaminoglycans.
An Advisory Committee briefing document by BioMarin on the MPS group of disorders states, “Mucopolysaccharidoses (MPS) and related diseases are genetic lysosomal storage diseases (LSD) caused by the body’s inability to produce specific enzymes. In individuals with MPS, the missing or insufficient enzyme activity prevents the proper intracellular recycling process of cellular materials. It results in the abnormal storage of materials in most body cells. As a result, progressive damage may occur throughout the body, including the heart, bones, joints, respiratory system, and central nervous system.”
It adds, “While the MPS diseases may not be apparent at birth, signs and symptoms develop with age as more cells become progressively damaged by the abnormal accumulation of cellular materials. The group of MPS disorders includes over a dozen identified syndromes, which differ in the deficient enzyme, accumulated intracellular products, and clinical manifestations. The subtyping of MPS disorders is based largely on the deficient enzyme.”
Subtypes of MPS
As per the National Organization for Rare Diseases (or NORD), the various subtypes of the MPS disorders are:
- MPS I H/S (Hurler/Scheie syndrome)
- MPS I H (Hurler disease)
- MPS I S (Scheie syndrome)
- MPS II (Hunter syndrome)
- MPS III A, B, C, and D (Sanfilippo syndrome)
- MPS IV A and B (Morquio syndrome)
- MPS VI (Maroteaux-Lamy syndrome)
- MPS VII (Sly syndrome)
- MPS IX (Hyaluronidase deficiency)
Existing therapies for MPS disorders
Existing therapies for treating mucopolysaccharidosis include enzyme replacement therapy and hematopoietic stem cell transplantation (or HSCT). Due to the advantage of exclusivity offered for orphan—or rare—diseases, companies such as Alexion Pharmaceuticals (ALXN), Regeneron Pharmaceuticals (REGN), and Shire (SHPG) are conducting research on orphan diseases.
Investors can opt for the PowerShares Dynamic Biotechnology & Genome Portfolio (PBE). PBE invests 5.4% of its portfolio in BioMarin.