UCB Licenses Sepracor U.S. patents for antihistamine Levocetirizine

BRUSSELS (Belgium) and MARLBOROUGH, Mass. (USA), February 23, 2006 -- UCB S.A. (EURONEXT: UCB) and Sepracor Inc. (Nasdaq: SEPR) today announced a licensing agreement relating to the antihistamine levocetirizine. Under this agreement, Sepracor has exclusively licensed to UCB all of Sepracor's patents and patent applications in the United States regarding levocetirizine and royalties will be payable to Sepracor on U.S. sales of levocetirizine products.

Under a separate agreement, Sepracor currently earns royalties from UCB on sales of levocetirizine in European countries where the product is sold. Levocetirizine is marketed by UCB under the brand names XYZAL® and XUSAL(TM) in the European Union for treatment of symptoms of seasonal and perennial allergic rhinitis, persistent allergic rhinitis, and chronic idiopathic urticaria (CIU, also known as hives of unknown cause) in adults and children aged 6 years and older.

"Sepracor is pleased to extend its licensing arrangement for levocetirizine to the United States. UCB has built a successful antihistamine franchise worldwide and we are optimistic about the opportunity UCB has to expand it with the introduction of levocetirizine in the U.S.," stated Timothy J. Barberich, Chairman and Chief Executive Officer of Sepracor.

"We are very excited about our new licensing relationship with Sepracor in the United States and the prospect of expanding our antihistamine business," stated Roch Doliveux, Chief Executive Officer of UCB.

About UCB

UCB (www.ucb-group.com) is a leading global biopharmaceutical company dedicated to the research, development and commercialization of innovative pharmaceuticals and biotechnology products in the fields of central nervous system disorders, allergy/respiratory diseases, immune and inflammatory disorders and oncology - UCB focuses on securing a leading position in severe disease categories. Employing 8,500 people in over 40 countries, UCB achieved revenues of EUR 2.1 billion (including net sales, royalties, and fees) in 2004. UCB is listed on the Euronext Brussels Exchange (UCB / UCBBt.BR / UCB BB) with a market capitalization of approximately EUR 5.8 billion. Worldwide headquarters are located in Brussels, Belgium.

About Sepracor

Sepracor Inc. is a research-based pharmaceutical company dedicated to treating and preventing human disease through the discovery, development and commercialization of innovative pharmaceutical products that are directed toward serving unmet medical needs. Sepracor's drug development program has yielded an extensive portfolio of pharmaceutical compound candidates with a focus on respiratory and central nervous system disorders. Sepracor's corporate headquarters are located in Marlborough, Massachusetts.

Forward-Looking Statement

This news release contains forward-looking statements that involve risks and uncertainties, including statements with respect to the safety, efficacy and potential benefits of levocetirizine, the development and commercialization of levocetirizine in the United States and Sepracor's receipt of royalties under the licensing agreements. Among the factors that could cause actual results to differ materially from those indicated by such forward- looking statements are: the results of research, development and clinical trials; the timing and success of submission, acceptance, and approval of regulatory filings; the time and resources UCB devotes to the development and commercialization of levocetirizine; the scope of Sepracor's and UCB's patents and the patents of others; the commercial success of levocetirizine in the United States; and certain other factors that are detailed in Sepracor's quarterly report on Form 10-Q for the quarter ended September 30, 2005 filed with the Securities and Exchange Commission.

In addition, the statements in this press release represent Sepracor's and UCB's expectations and beliefs as of the date of this press release. Sepracor anticipates that subsequent events and developments may cause these expectations and beliefs to change. However, while Sepracor and UCB may elect to update these forward-looking statements at some point in the future, it specifically disclaims any obligation to do so. These forward- looking statements should not be relied upon as representing Sepracor's and UCB's expectations or beliefs as of any date subsequent to the date of this press release.

Xusal(TM) is a trademark and Xyzal® is a registered trademark of UCB S.A.

Inquiries:

UCB
Vice President, Investor Relations & Corporate Communications
Jean-Christophe Donck
Tel   32 2 559 9346
Fax  32 2 559 9571
JC.Donck@UCB-Group.com

Sepracor Inc.
Executive Vice President & Chief Financial Officer
David P.Southwell

Vice President, Investor Relations & Corporate Communications
Jonae Barnes
Tel  1 508 481 6700
Jonae.Barnes@sepracor.com