<DOCUMENT>
<TYPE>EX-99.1
<SEQUENCE>3
<FILENAME>a2070528zex-99_1.txt
<DESCRIPTION>EXHIBIT 99.1
<TEXT>
<Page>


                                                                       Exhibit 1

                             JOINT FILING AGREEMENT

We, the signatories of the statement on Schedule 13G to which this Agreement is
attached, hereby agree that such statements is, any amendments thereto filed by
any of us will be, filed on behalf of each of us.

FEBRUARY 14, 2002                         ARTAL GROUP S.A.

                                          By:      /s/ PAUL KOHLER
                                          Name:    Paul Kohler
                                          Title:   Managing Director


                                          ARTAL LUXEMBOURG S.A.

                                          By:      /s/ PAUL KOHLER
                                          Name:    Paul Kohler
                                          Title:   Managing Director

</TEXT>
</DOCUMENT>