Although there are currently no cures for lysosomal disorders such as Gaucher disease, cystinosis, Pompe disease and Hunter syndrome, there are several approved treatments. Each approach has its own advantages and limitations.
Enzyme replacement therapy, or ERT, is the standard of care for lysosomal disorders. As the name implies, ERT is designed to replace the enzyme that is missing or defective in people with lysosomal disorders.
Among the advantages of ERTs:
- They slow progression of disease and in some cases can reverse damage to certain organs.
- ERTs can significantly improve symptoms. For example, in people living with Gaucher disease, ERTs can dramatically reduce the size of enlarged spleens and livers.
- ERTs have established a favorable safety profile and are generally well-tolerated over decades of use.
ERTs also have limitations:
- Enzyme replacement does not address the underlying cause of lysosomal disorders and does not halt the overall progression of disease.
- ERTs do not cross the blood-brain barrier and therefore cannot address neurological symptoms that may result from disease progression. For example, people with Gaucher disease type 1 have a significantly higher risk of developing Parkinson’s disease.
- Once ERTs are infused, the body begins to immediately break them down in the liver as well as in the circulation. That’s why people on ERT typically must undergo lifelong biweekly infusions of the enzyme treatment.
Substrate reduction therapy, or SRT, is designed to limit the production of the specific toxic molecules that build up within the cell. This type of oral medication is approved for the treatment of Gaucher disease and is typically given to people with less severe forms of the disease.
In addition to ERT and SRT, individuals living with lysosomal disorders may also take medications to help with symptoms such as pain, high blood pressure or depression.