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8800 Technology Forest Place
The Woodlands, Texas 77381
August 10, 2007
Dear Fellow Stockholder:
According to our latest records, we have not yet received your proxy for the important Special Meeting of Lexicon Pharmaceuticals, Inc. stockholders, to be held on August 23, 2007. Your Board of Directors unanimously recommends that stockholders vote FOR both proposals on the agenda.
Please help your company avoid the expense of further solicitation by voting TODAY by telephone, via the Internet, or by signing, dating and returning the enclosed proxy card in the envelope provided.
Thank you for your cooperation.
Very truly yours,
Jeffrey L. Wade
You can vote your shares by telephone, or via the Internet.
Please follow the easy instructions on the enclosed card.
If you have any questions, or need assistance in the last-minute
voting your shares, please call our proxy solicitor,
TOLL-FREE, at (888) 750-5834.



Lexicon has filed a proxy statement and other documents with the Securities and Exchange Commission relating to the approval of the Invus transactions. Stockholders are urged to carefully read the proxy statement, because it contains important information regarding Lexicon and the Invus transactions. A definitive proxy statement has been sent to stockholders seeking their approval of the Invus transactions. Stockholders may obtain a free copy of the proxy statement and other documents containing information about Lexicon, without charge, at the SEC’s website at Copies of the definitive proxy statement and the SEC filings that are incorporated by reference in the proxy statement may also be obtained for free by directing a request to Lexicon Pharmaceuticals, Inc., 8800 Technology Forest Place, The Woodlands, Texas 77381, Attention: Corporate Communications.
Lexicon and its officers and directors may be deemed to be participants in the solicitation of proxies from the stockholders. Information about these persons can be found in Lexicon’s Annual Report on Form 10-K filed with the SEC, and additional information about such persons may be obtained from the proxy statement.