The FDA recently approved a biologics license application (BLA) for Myozyme (alglucosidase alfa, rhGAA), the first treatment for patients with Pompe disease, a rare but severely debilitating disease. Pompe disease, which affects one in 40,000-300,000 individuals, drastically reduces a person’s muscle and respiratory function. Myozyme had been granted FDA Orphan Drug designation and was approved under a priority review. Orphan products are developed to treat rare diseases or conditions that affect fewer than 200,000 people in the U.S. The Orphan Drug Act provides a seven-year period of exclusive marketing to the first sponsor who obtains marketing approval for a designated orphan drug.
“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,” said Dr. Steven Galson, the director of FDA’s Center for Drug Evaluation and Research. “Until now, Pompe disease has had no approved treatment.”
Pompe disease is an inherited disease caused by the deficiency or lack of the enzyme acid alpha-glucosidase, which is essential for normal muscle development and function. The disease, which usually results in death from respiratory failure, is rapidly fatal in newborn babies.
The FDA approved Myozyme for administration by intravenous infusion of solution into a vein. The safety and efficacy of Myozyme were assessed in two separate clinical trials in 39 infantile-onset patients with Pompe disease ranging in age from 1 month to 3.5 years at the time of the first infusion.
Patient survival without needing invasive ventilatory support was substantially greater in the Myozyme-treated infants than would be expected compared to the known high mortality of untreated patients of similar age and disease severity. The drug’s safety and effectiveness in other forms of Pompe disease have not been adequately studied.
The most serious adverse reactions reported with Myozyme were heart and lung failure and allergic shock. Most common reactions included pneumonia, respiratory failure and distress, infections and fever. A boxed warning is included in the Myozyme label to warn about the possibility of life-threatening allergic reactions.
Myozyme is manufactured by Genzyme Corp. in Cambridge, Mass.