New Website Offers Comprehensive Information on Hunter Syndrome

CAMBRIDGE, Mass., March 28 /PRNewswire-FirstCall/ — Transkaryotic Therapies, Inc. today announced the launch of a new educational website focused on Hunter syndrome. Hunter syndrome, also referred to as MPS II, is a rare disorder in a class referred to as mucopolysaccharidoses or MPS. The site, , is a resource center for the Hunter community to access information about the genetics, diagnosis and management of Hunter syndrome as well as information about the drug development process.
TKT recently completed a multinational Phase III clinical trial evaluating an investigational enzyme replacement therapy for the treatment of Hunter syndrome. Results of the study are expected to be announced in June 2005 and, if positive, the company will file for regulatory approval in the U.S. and Europe in the second half of 2005.
“As we continue to learn more about MPS disorders and as new treatments are being developed, we hope to improve awareness of these rare and often life-threatening disorders. Easy access to information is the best way for families and practitioners to stay informed about new developments in the area,” said Joseph Muenzer, M.D., Ph.D., of the University of North Carolina at Chapel Hill, an internationally recognized leader in the diagnosis and treatment of MPS disorders and the lead investigator of TKT’s Phase III trial. “The launch of this site marks an important step toward offering patients, families and healthcare providers access to important medical and educational information relating to Hunter syndrome.”
The website provides a comprehensive overview of Hunter syndrome, including resources for patients and healthcare professionals, information on clinical trials and a patient outcomes survey, as well as the ability to stay informed as new information about Hunter syndrome becomes available on the site. In addition, TKT expects to update and expand the site on a regular basis.
About Hunter Syndrome
Hunter syndrome is a hereditary disorder characterized by the body’s inability to produce the enzyme iduronate-2-sulfatase, which is essential in the continuous process of replacing and breaking down glycosaminoglycans (GAG). As a result, GAG remains stored in cells in the body causing progressive damage. The symptoms of Hunter syndrome are usually not visible at birth, but usually start to become noticeable after the first year of life. Often the first symptoms may include hernias, frequent ear infections, runny noses, and abnormal facial appearance.
As the disease progresses, a variety of symptoms appear including, enlarged liver and spleen, heart failure, obstructive airway disease, sleep apnea, joint stiffness, and, in some cases, central nervous system involvement. If central nervous system involvement exists, the life expectancy for patients with Hunter syndrome is typically 10-15 years of age, however, in the attenuated form of the disease, patients can survive into the fifth or sixth decade of life. TKT believes there are approximately 2,000 patients worldwide afflicted with Hunter syndrome in jurisdictions where reimbursement may be possible.
About TKT
Transkaryotic Therapies, Inc. is a biopharmaceutical company primarily focused on researching, developing and commercializing treatments for rare diseases caused by protein deficiencies. Within this focus, the company markets Replagal(TM), an enzyme replacement therapy for Fabry disease, and is developing treatments for Hunter syndrome and Gaucher disease. In addition to its focus on rare diseases, TKT intends to commercialize Dynepo(TM), its Gene- Activated(R) erythropoietin product for anemia related to kidney disease, in the European Union. TKT was founded in 1988 and is headquartered in Cambridge, Massachusetts, with additional operations in Europe, Canada and South America. Additional information about TKT is available on the company’s website at
This press release contains forward-looking statements within the meaning of the Private Securities Litigation Reform Act of 1995, including statements containing the words “believes,”anticipates,”plans,”expects,”intends,”should,”could,”
“will,”may,” and similar expressions. There are a number of important factors that could cause the company’s actual results to differ materially from those indicated by such forward-looking statements, including: whether I2S will be safe and effective as a treatment for Hunter syndrome, whether TKT will successfully manufacture adequate supply of I2S, whether future trials of I2S will be conducted, whether future trials of I2S will commence on a timely basis, whether the FDA and equivalent regulatory authorities will approve I2S on a timely basis, or at all, whether, if approved, this product will achieve commercial success, whether competing products will reduce any market opportunity that may exist for I2S, and other factors set forth under the caption “Risk Factors” in the company’s Annual Report on Form 10-K for the year ended December 31, 2004, which is on file with the Securities and Exchange Commission and are incorporated herein by reference. While the company may elect to update forward-looking statements at some point in the future, the company specifically disclaims any obligation to do so, even if its expectations change.

Gene-Activated(R) is a registered trademark and Replagal(TM) is a trademark of Transkaryotic Therapies, Inc. Dynepo(TM) is a trademark of Sanofi-Aventis SA.
Investor and Media Contact: Patient and Physician Contact:
Daniella M. Lutz Leanne Torrie
Manager, Corporate Communications Manager, Patient Services
(617) 349-0205 (617) 613-4499
Photo: NewsCom: Archive: Photo Desk,
Transkaryotic Therapies, Inc.
CONTACT: Investor and Media Contact: Daniella M. Lutz, Manager, CorporateCommunications, +1-617-349-0205, or Patient and Physician Contact: LeanneTorrie, Manager, Patient Services, +1-617-613-4499, both of TranskaryoticTherapies, Inc.