Exhibit 1

Joint Filing Statement

      Pursuant to Rule 13d-1(f)(1), we undersigned, hereby express our agreement that the attached Schedule 13G (including all amendments thereto) is filed on behalf of each of the undersigned.

BB BIOTECH AG

            /s/ ANDERS HOVE
By: Anders Hove
Its: Authorized Signatory
Date: February 14, 2003             /s/ ADRIAN BRUENGGER
By: Adrian Bruengger
Its: Authorized Signatory
Date: February 14, 2003

BIOTECH GROWTH N.V.

            /s/ ANDERS HOVE
By: Anders Hove
Its: Authorized Signatory
Date: February 14, 2003             /s/ ADRIAN BRUENGGER
By: Adrian Bruengger
Its: Authorized Signatory
Date: February 14, 2003

BIOTECH TARGET N.V.

            /s/ ANDERS HOVE
By: Anders Hove
Its: Authorized Signatory
Date: February 14, 2003             /s/ ADRIAN BRUENGGER
By: Adrian Bruengger
Its: Authorized Signatory
Date: February 14, 2003

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