<PAGE>
EXHIBIT 99.1
FOR IMMEDIATE RELEASE
TKT RECEIVES FDA COMPLETE REVIEW LETTER ON REPLAGAL-TM-
CAMBRIDGE, MA, JANUARY 3, 2001 --- Transkaryotic Therapies, Inc. (Nasdaq: TKTX)
today announced that it has received a complete review letter from the U.S. Food
and Drug Administration (FDA) concerning its Biologics License Application (BLA)
for Replagal-TM- (agalsidase alfa), an investigational enzyme replacement
therapy for the treatment of Fabry disease. In the letter, the FDA has asked for
further explanation in several areas and requested additional data. TKT has
initiated the collection of these data, but until there is an opportunity for
further discussion with the FDA, TKT cannot make projections about the timing of
future FDA decisions concerning the approval of Replagal.
"While we are disappointed that the FDA did not approve Replagal at this time,
we are working diligently to respond quickly to their requests for additional
data," stated Richard F Selden, M.D., Ph.D., President and Chief Executive
Officer of TKT. "We believe Replagal is the best hope for patients suffering
from this life-threatening disease, and we remain firmly committed to bringing a
safe and effective therapy to market for the thousands of patients affected by
Fabry disease. We will continue to do everything we can to make this therapy
available as soon as possible and we look forward to working with the FDA
towards attaining this goal."
The BLA submission was based on data generated from two independent pivotal
studies, conducted at the National Institutes of Health (NIH) and Royal Free
Hospital in the United Kingdom, as well as long-term data from an additional six
months of treatment from an open-label maintenance study at the NIH. Data from
the pivotal NIH study were presented at the 50th Annual Meeting of the American
Society of Human Genetics in October 2000. Data generated from the United
Kingdom study will be presented at an upcoming medical meeting.
About Fabry Disease
Fabry disease is an inherited rare genetic disorder caused by deficient activity
of the lysosomal enzyme alpha-galactosidase A. In patients with Fabry disease,
globotriaosylceramide (Gb3) accumulates in various organs and tissues of the
body due to the deficiency of alpha-galactosidase A. As a result, the deposits
of this material can result in extreme pain, severe kidney damage,
cardiovascular disease, and stroke. Due to its rarity and vast array of
symptoms, diagnosis is often difficult and affected individuals have a
significantly reduced quality of life and a greatly shortened life expectancy.
TKT estimates that approximately 5,000 patients worldwide are affected by Fabry
disease.
<PAGE>
About TKT
Transkaryotic Therapies, Inc. (TKT) is a biopharmaceutical company dedicated to
the development and commercialization of products based on its three proprietary
development platforms: Gene-Activated-Registered Trademark- proteins, Niche
Protein-TM- products, and Gene Therapy. The Company's gene activation technology
is a proprietary approach to the large-scale production of therapeutic proteins,
which does not require the cloning of genes and their subsequent insertion into
non-human cell lines. TKT's Niche Protein product platform is based on protein
replacement for the treatment of rare genetic diseases, a group of disorders
characterized by the absence of certain metabolic enzymes. The Company's Gene
Therapy technology, known as Transkaryotic Therapy-TM-, is focused on the
commercialization of non-viral, ex vivo gene therapy products for the long-term
treatment of chronic protein deficiency states.
This press release contains forward-looking statements that involve a number of
risks and uncertainties. For this purpose, any statements contained herein that
are not statements of historical fact may be deemed to be forward-looking
statements. Without limiting the foregoing, the words, "believes,"
"anticipates," "plans," "expects," "intends," and similar expressions are
intended to identify forward-looking statements. Important factors that could
cause actual results to differ materially from the expectations described in
these forward-looking statements are set forth under the caption "Certain
Factors That May Affect Future Results" in TKT's Annual Report on Form 10-K for
the year ended December 31, 1999 and updated in TKT's Quarterly Report on Form
10-Q for the quarter ended September 30, 2000, which are both on file with the
Securities and Exchange Commission and incorporated herein by reference. These
important factors include risks as to whether TKT's products, such as Replagal,
will advance in the clinical trials process, the timing of such clinical trials,
whether the clinical trial results will warrant continued product development,
and whether TKT's products, such as Replagal, will receive approval from the
U.S. Food and Drug Administration or equivalent regulatory agencies, and, if
such products receive approval, whether they will be successfully marketed; the
results of any patent litigation in which TKT is involved or may become
involved; competition; and TKT's dependence on collaborators.
Gene-Activated-Registered Trademark- is a registered trademark and Niche
Protein-TM-, Replagal-TM-, TKT-TM-, and Transkaryotic Therapy-TM- are trademarks
of Transkaryotic Therapies, Inc.
Please visit our web site at www.tktx.com for additional information about
Transkaryotic Therapies, Inc.
CONTACT:
Justine E. Koenigsberg
Manager, Corporate Communications
(617) 349-0271
###
