EXHIBIT 1

DECLARATION OF CONSENT TO JOINT FILING BY SANOFI-AVENTIS, AVENTIS PHARMACEUTICALS INC, AVENTIS HOLDINGS INC AND AVENTIS INC.

WHEREAS, in accordance with Rule 13d-1(k) under the Securities and Exchange Act of 1934 (the “Act”), only one joint statement and any amendments thereto need to be filed whenever one or more persons are required to file such a statement or any amendments thereto pursuant to Section 13(d) of the Act with respect to the same securities, provided that said persons agree in writing that such statement or amendments thereto is filed on behalf of each of them;

NOW, THEREFORE, the parties hereto agree as follows:

Sanofi-aventis, Aventis Pharmaceuticals Inc, Aventis Holdings Inc and Aventis Inc. hereby agree, in accordance with Rule 13d-1(k) under the Act, to file a statement on Schedule 13G relating to their ownership of the Common Stock of the Issuer and do hereby further agree that said statement shall be filed on behalf of each of them.

	SANOFI-AVENTIS.
Date: February 13, 2007	By:			/s/ Jean-Claude Leroy
	Jean-Claude LEROY
	Executive Vice President
	Chief Financial Officer
	AVENTIS PHARMACEUTICALS
	INC.
Date: February 13, 2007	By:				/s/ John M. Spinnato
	John M. SPINNATO
	Vice President and General Counsel
	- Pharmaceutical Operations
	AVENTIS HOLDINGS INC.
Date: February 13, 2007	By:	/s/ Kathleen A. Winter
	Kathleen A. WINTER
	President
	AVENTIS INC.
Date: February 13, 2007	By:		/s/ Kathleen A. Winter
	Kathleen A. WINTER
	President