Genzyme seeks OK for Pompe disease drug
An experimental drug made by Genzyme Corp. sharply improved survival in infants with an untreatable genetic disorder called Pompe disease, according to an application the company filed with the Food and Drug Administration yesterday.
The company asked for priority approval for the drug, Myozyme. If granted, Genzyme could begin selling the drug early next year.
Myozyme would be the first treatment for Pompe, a genetic ailment with fewer than 10,000 sufferers worldwide.
Infants with severe Pompe disease lack an enzyme necessary to clear waste out of cells, and quickly develop floppy muscles and grossly enlarged hearts. They rarely survive to their first birthday.
Adults with milder forms of Pompe tend to have weak muscles and trouble breathing normally.
If approved, Myozyme would be the latest in Genzyme's family of high-priced drugs designed to replace missing enzymes in people with a rare group of genetic diseases called lysosomal storage disorders. It would join Cerezyme, which has 4,400 patients, and a newer drug called Fabrazyme, with about 1,500. Genzyme also sells a similar drug, Aldurazyme, in a licensing agreement with the California biotech company BioMarin Pharmaceuticals Inc.
Overall, Genzyme sells about a dozen drugs and other biological products. By far the largest is Cerezyme, with about $900 million in sales a year.
Yesterday's application was based on a clinical trial of Myozyme that began in spring 2003. Doctors gave weekly infusions of the drug to 18 children with Pompe disease and compared their health to what would be expected of Pompe patients from historical records.
Genzyme said that 15 of the children in the trial, or 83 percent, survived to the age of 18 months without a ventilator, compared to only 2 percent of Pompe infants in medical records surveyed.
''This is a very exciting and hopeful moment for Pompe patients and their families," said Henri A. Termeer, Genzyme's chief executive, in a statement yesterday.
Based on the results of an earlier trial, the company already has applied to sell the drug in Europe.
The company already has expanded its production capacity to produce Myozyme, which like many biotechnology drugs is a protein produced by animal cells in a fermenting tank.
Genzyme has added two bioreactors for Myozyme in its manufacturing plant in Allston and two more in Framingham. It also plans to manufacture the drug in Belgium.
According to a Genzyme scientist, about 140 people are currently on Myozyme worldwide in various trials and drug availability programs.
Genzyme has not said how much it expects to earn from Myozyme or what it intends to charge if the drug is approved.
Phil Nadeau, a biotech analyst for SG Cowen & Co., said on Thursday that he expects Myozyme sales to be around $100 million a year, considerably less than Cerezyme or Fabrazyme, although the worldwide patient populations are similar.
The difference, he said, was partly because the majority of Pompe sufferers have the less-severe adult forms of the disease and can survive without the drug.
Stephen Heuser can be reached at sheuser@globe.com. 
