A biologics licence application has been approved by the FDA for Myozyme (alglucosidase alfa, rhGAA), this is the first treatment for Pompe disease, a rare, but serious disease which drastically reduces a person’s muscle and respiratory function.

About 40,000 individuals suffer from Pompe disease.

Myozyme had had Orphan Drug designation, it was approved under a priority review.

What is Orphan Drug Designation?

It is a drug which is developed to treat rare conditions or diseases. The disease must affect fewer than 200,000 people in the USA. The maker of an orphan designated drug that gets approval has a seven year exclusive marketing period for that drug. The reason behind this seven year exclusive marketing period is to encourage drug companies to develop products that will not sell to big markets – rare diseases are not big markets.

Dr. Steven Galson, the director of FDA’s Center for Drug Evaluation and Research, said “This approval is another example of the benefits of the Orphan Drug program, which provides incentives for the development of treatments for diseases affecting fewer than 200,000 patients in the United States a year. Until now, Pompe disease has had no approved treatment.”

The enzyme called acid alpha-glucosidase is essential for normal muscle development. Patients with Pompe disease either lack it or have a deficiency of this enzyme. Pompe disease is an inherited disease. It is common for patients with Pompe disease to die from respiratory failure. It is rapidly fatal for newborn babies.

Myozyme has been approved for administration by intravenous infusion of solution into a vein.

Clinical trials had shown that infant survival without respiratory support was much greater for infants given Myozyme. There were two clinical trials with 39 infants, aged 1 month to 3.5 years. All the children had infantile-onset Pompe disease.

Myozyme’s most serious reported adverse events were heart and lung failure and allergic shock. A boxed warning is included in the Myozyme label to warn about the possibility of life-threatening allergic reactions.

What is Pompe disease?

It is a rare neuromuscular disease that affects babies, children and adults who inherit a defective gene. Pompe disease is one of 40 genetic diseases known as Lysosomal Storage Disorders. Pompe is also known as a metabolic muscle disease as the muscle weaknesses occur as a result of changes inside the body’s cells.

Pompe disease was first described by J.C Pompe, a Dutch doctor, in 1932. He had observed an infant with severe muscle weakness and a very enlarged heart.

Symptoms of Pompe Disease

— Progressive muscle weakness
– Especially muscles for breathing and mobility
– In infants the heart muscle is severely affected

There are two broad groups of patients

— Infants (infantile-onset Pompe disease). Symptoms appear during first months of life. The disease progresses rapidly and is generally fatal before the baby is one year old. About one third of all Pompe disease cases.

— Patients over one-year-old. Could be babies, children or adults (late-onset Pompe disease). Progresses more slowly than infantile-onset. Muscles weaken progressively. About two thirds of all Pompe disease cases.

Pompe disease does not appear to affect mental development.

Pompe disease affects both men and women equally. It also appears more or less equally among all ethnic groups, with a slightly higher incidence among African-Americans, as well as in Southern China and Taiwan.

Click here for more information on Pompe Disease.

Other useful links:

www.pompe.com
unitedpompe.com/magazine.cfm
pompe.org.uk
ninds.nih.gov/disorders/pompe/pompe.htm

Genzyme Corp. in Cambridge, Mass. Manufactures Myozyme.

Written by: Christian Nordqvist
Editor: Medical News Today