EXHIBIT 99.1


CONTACT:
Justine Koenigsberg
Director, Corporate Communications
(617) 349-0271


FOR IMMEDIATE RELEASE


               U.S. DISTRICT COURT ISSUES RULING IN ERYTHROPOIETIN

                                PATENT LITIGATION


         CAMBRIDGE, MA, JANUARY 19, 2001 - Transkaryotic Therapies, Inc.
(Nasdaq: TKTX) today announced that Judge William G. Young of the U.S. District
Court of Massachusetts has issued an opinion in a patent infringement suit Amgen
brought against Aventis Pharma and TKT involving Dynepo-TM-, the companies'
Gene-Activated-Registered Trademark- erythropoietin being developed in the
United States and Europe for the treatment of anemia.

Judge Young ruled in favor of Amgen on a number of issues. He held that claims 2
through 4 of Amgen's U.S. Patent No. 5,621,080, while not literally infringed,
were valid and infringed under the doctrine of equivalents. He held that four of
the five claims, claims 1,3,4, and 6, of Amgen's U.S. Patent No. 5,756,349 were
valid and literally infringed. He also held that claim 1 of Amgen's U.S. Patent
No. 5,955,422 was valid and literally infringed.

Judge Young ruled in favor of TKT and Aventis on a number of issues. He held
that Amgen's U.S. Patent No. 5,547,933 was not infringed, and that it would be
invalid if it were infringed. He held that Amgen's U.S. Patent No. 5,618,698 was
not infringed. He held that claim 7 of Amgen's U.S. Patent No. 5,756,349 was not
infringed. He held that Amgen's U.S. Patent No. 5,621,080 was not literally
infringed.

"Although we are disappointed by today's ruling, we are grateful for Judge
Young's long and intensive efforts on this case. We remain confident that our
position is strong and intend to appeal this decision," stated Richard F.
Selden, M.D., Ph.D., President and Chief Executive Officer of TKT. "Furthermore,
we congratulate Amgen on the initial ruling in the case, but we look forward to
competing with them to provide patients with the best possible product after a
successful appeal."




Dynepo is a novel human erythropoietin for the treatment of anemia. Clinical
development testing of Dynepo as a treatment for anemia of renal failure in
dialysis and pre-dialysis patients has been completed, and Aventis Pharma has
been pursuing marketing authorization in the both the U.S. and Europe.

A copy of the opinion is available on the District Court of Massachusetts'
website at http://www.mad.uscourts.gov.

TKT will host a conference call at 10:00 am EST Monday, January 22, 2001 to
discuss the recent decision in the Dynepo patent litigation. Participants may
access the call by dialing 800-789-2340 in the U.S. or 706-634-0776 outside of
the U.S. This call will also broadcast live over the Internet at
http://www.tktx.com/f_investor.htm. Please dial in 5 to 10 minutes prior to the
scheduled conference call time.

The conference call will be archived on the Internet for 24 hours for those who
are unable to hear it live. A replay of the call will also be accessible by
telephone after 12:00 pm EST Monday, January 22, 2001 through midnight EST on
Tuesday, January 23, 2001. To replay the call, dial 800-642-1687 in the United
States and 706-645-9291 internationally, using access code 888986.

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 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 DYNEPO, 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 INCLUDING THE LITIGATION WITH AMGEN
REFERENCED ABOVE, OR THAT THE APPEAL IN THIS OR ANY OTHER CASE WILL BE
SUCCESSFUL, OR MAY BECOME INVOLVED; COMPETITION; AND TKT'S DEPENDENCE ON
COLLABORATORS.

GENE-ACTIVATED-Registered Trademark- IS A REGISTERED TRADEMARK AND NICHE
PROTEIN-TM- TKT-TM-, AND TRANSKARYOTIC THERAPY-TM- ARE TRADEMARKS OF
TRANSKARYOTIC THERAPIES, INC. DYNEPO-TM- IS A TRADEMARK OF AVENTIS PHARMA.

PLEASE VISIT OUR WEB SITE AT www.tktx.com FOR ADDITIONAL INFORMATION ABOUT
TRANSKARYOTIC THERAPIES, INC.


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