Genzyme Expands Global Infrastructure for Manufacturing, R&D

European Investments to Support Growth of Antibody, Protein Products

Genzyme Corporation (Nasdaq: GENZ) announced today that it has substantially strengthened its global infrastructure for manufacturing and product development through four major expansion projects in Belgium, Ireland, and the United Kingdom. The new and expanded facilities officially opened this week will support Genzyme’s continued growth and innovation, particularly in the areas of antibody and protein-based medicines. Together the projects represent capital investments of more than $500 million over several years, a significant portion of which has already occurred.

The facilities include a new bio-manufacturing plant in Geel, Belgium for the production of monoclonal antibodies and proteins; expansion of Genzyme’s manufacturing centers in Waterford, Ireland and Haverhill, UK; and creation of an antibody discovery research facility in Cambridge, United Kingdom.

Genzyme also announced today that in addition to producing humanized monoclonal antibodies at its Geel plant, this facility will be used to meet the anticipated demand for Myozyme® (alglucosidase alfa), an enzyme replacement therapy currently under review with U.S. and European regulatory authorities for the treatment of Pompe disease. Production in Geel will augment that at Genzyme’s flagship protein manufacturing facility in Boston (Allston), Massachusetts.

“We are very pleased to have the opportunity to further deepen our presence in the European medical and biotechnology community, which has been an important part of Genzyme’s growth since our earliest days,” said Henri A. Termeer, chairman and chief executive officer, Genzyme Corporation. “As our presence in Europe has grown, so has our ability to serve the needs of patients throughout the world, using a variety of approaches to address a broad range of serious diseases.”

Genzyme has a total of seven manufacturing sites in Europe, including a small molecule production site in Liestal, Switzerland, a polyclonal bio-manufacturing site in Lyon, France, and diagnostic manufacturing facilities in Kent, UK and Rüsselsheim, Germany. The latest additions to Genzyme’s European infrastructure include:

Belgium

Genzyme’s first manufacturing facility worldwide for the production of humanized monoclonal antibodies will produce Campath® (alemtuzumab for injection), used to treat B-cell chronic lymphocytic leukemia (B-CLL). Monoclonal antibodies form an increasingly important part of Genzyme’s commercial and development efforts across a range of diseases. Genzyme will begin preparations to produce in-house batches of Campath in 2005, and anticipates that it will produce the first complete production runs within a year. This plant is located on the site of a facility acquired in 2001 from Pharming, N.V., which was working to develop a therapy for Pompe disease.

The addition of protein manufacturing capabilities in Geel will help ensure that Genzyme is able to meet the anticipated demand for Myozyme in Europe and throughout the world. If approved, Myozyme would be the first treatment developed for patients with Pompe disease, a debilitating and often fatal muscle disorder resulting from an inherited enzyme deficiency. In infants, Pompe disease is typically fatal within the first year of life.

Ireland

Expansion in Waterford, Ireland will make this facility the major European production and distribution center for a broad range of Genzyme products. The latest expansion at Waterford adds a high-quality biological fill/finish center to support the growth of protein and antibody products manufactured at other Genzyme facilities. It will be the European fill/finish center for Genzyme’s enzyme replacement therapies for rare genetic diseases, and for Thymoglobulin® (anti-thymocyte globulin) for the treatment of acute rejection in patients with a kidney transplant.

Waterford is already the primary tableting and bottling center for Renagel. In 2004, this plant produced approximately 3 million bottles of Renagel for patients with chronic kidney disease who are on dialysis.

United Kingdom

Genzyme’s first discovery laboratory outside of the United States will bring it into close proximity to renowned academic institutions, a cluster of nearly 200 biotechnology companies, and a large pool of world-class scientific talent. Genzyme’s work at this site focuses primarily on the application of antibody technology to oncology, renal disease and immune-mediated diseases, and is complemented by an existing partnership with Cambridge Antibody Technology to develop recombinant anti-TGFβ antibodies in immune diseases. With its proximity to the London-based European Medicines Agency, the Cambridge location will also serve as an important center for clinical trial support in Europe, where Genzyme currently has more than 30 ongoing clinical trials.

In addition, Genzyme’s Haverhill, UK plant, which was significantly expanded in recent years to produce bulk sevelamer hydrochloride for Renagel, is being further expanded to support clinical development of a wide range of potential new therapies, including sevelamer carbonate for chronic kidney disease, and Tolevamer for Clostridium difficile associated diarrhea.

About Genzyme

One of the world’s leading biotechnology companies, Genzyme is dedicated to making a major positive impact on the lives of people with serious diseases. Founded in 1981, Genzyme has grown from a small start-up to a diversified enterprise with 7,600 employees in locations spanning the globe, and 2004 revenues of $2.2 billion. With many established products and services helping patients in more than 80 countries, Genzyme is a leader in the effort to develop and apply the most advanced technologies in the life sciences. The company’s products and services are focused on rare inherited disorders, kidney disease, orthopedics, cancer, transplant and immune diseases, and diagnostic testing. Genzyme’s commitment to innovation continues today with a substantial development program focused on these fields, as well as heart disease and other areas of unmet medical need.

This press release contains forward-looking statements, including without limitation statements about: intended manufacturing and other uses for Genzyme’s new and expanded facilities, including the production of Myozyme at Genzyme’s facility in Geel and the use of Waterford as a fill/finish center for Genzyme’s enzyme replacement therapies; anticipated timing for the production of Genzyme products at these facilities, including for the manufacture of Campath in Geel; and the intention to use Genzyme’s Cambridge and Haverhill facilities to support clinical development of new therapies. These statements are subject to risks and uncertainties that could cause actual results to differ materially from those projected in these forward-looking statements. These risks and uncertainties include, among others: the ability to obtain any governmental or other required approvals and to implement all structural and organizational changes necessary for the expansion of operations at Genzyme’s European facilities; and the risks and uncertainties described in reports filed by Genzyme with the Securities and Exchange Commission under the Securities Exchange Act of 1934, as amended, including without limitation the information under the heading “Factors Affecting Future Operating Results” in Genzyme’s Quarterly Report on Form 10-Q for the period ended June 30, 2005. Genzyme cautions investors not to place substantial reliance on the forward-looking statements contained in this press release. These statements speak only as of the date of this press release, and Genzyme undertakes no obligation to update or revise these statements.

Contact Information

Erin Emlock

Public Relations Specialist

Genzyme Corporation

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