FDA OKs LIFESAVING TREATMENT
FOR POMPE DISEASE

Rare Genetic Disorder Among 40 Diseases
Covered by Muscular Dystrophy Association

TUCSON, Ariz., April 28, 2006 — The Food and Drug Administration today announced approval of Myozyme, a new treatment for patients with Pompe disease, a rare genetic disorder also known as acid maltase enzyme deficiency. The condition is one of more than 40 neuromuscular diseases covered by the Muscular Dystrophy Association (MDA), which sponsored early research in Pompe disease and also helped support clinical testing of Myozyme.

"This is the first definitive treatment for a genetic neuromuscular disease in our program, and this important announcement represents the culmination of many years of intensive research," MDA Medical Director Valerie Cwik said. "Everyone who has ever donated to MDA can take pride in their role in helping to bring about this lifesaving achievement. This news also offers hope to the hundreds of thousands of other people affected by the diseases in the MDA program, because it shows that support and research can lead to successful treatments."

Myozyme was developed by Genzyme Corp. (www.genzyme.com), a Cambridge, Mass., biotechnology company. Early-stage research to develop a therapy for Pompe disease was supported by a number of institutions, including MDA, Duke University and Erasmus University. Genzyme previously developed enzyme replacement therapies for three other rare genetic disorders - Gaucher disease, Fabry disease and MPS1.

Acid maltase, which is also known as acid alpha glucosidase, or GAA, normally breaks down glycogen (stored sugar) in specialized compartments in cells. Patients with Pompe disease lack this enzyme. As a result, glycogen builds up in muscle cells and ultimately destroys them.

In the infantile-onset form of the disease, GAA is completely or mostly absent. In these infants, the build up of glycogen leads to muscle weakness with respiratory and heart failure. Previously, no treatment other than supportive care has been available for patients with infantile-onset Pompe. Infants with the disease typically died within their first year.

In later-onset Pompe disease, disease progression often leads to increased weakness of limb and respiratory muscles and variable survival time. Severity and life span depend upon how much enzyme activity the patient retains.

Genzyme, with supplemental support from MDA, completed two clinical trials of Myozyme in infantile-onset Pompe disease and is currently conducting a Myozyme trial with patients who have the late-onset form of the disease. Several MDA-affiliated physicians have participated in this testing. (For details about clinical trials, see www.clinicaltrials.gov; enter "Myozyme" in the search box.)

"Myozyme provides new hope to thousands of people living with Pompe disease in the United States and around the world who formerly had no effective treatment options available. The effort to develop Myozyme has required the enormous commitment of many people throughout Genzyme and across the Pompe community," said Edward Kaye, Genzyme's vice president of clinical research.

Myozyme is typically administered intravenously via infusion every other week throughout the patient's life. Patients will be able to arrange their Myozyme infusions through their local MDA clinic in most cases.

For more information about Genzyme's Pompe disease programs, see www.pompe.com and www.Myozyme.com.

MDA (www.mda.org), founded in 1950, is a voluntary health agency working to defeat more than 40 neuromuscular diseases through programs of worldwide research, comprehensive services, and far-reaching professional and public health education.