Exhibit 99.1

This Statement on Form 4 is filed by the Reporting Persons listed below.

Name of Designated Filer: INVUS PUBLIC EQUITIES, L.P.

Date of Event Requiring Statement: November 15, 2017.

Issuer Name: Lexicon Pharmaceuticals, Inc. [LXRX]


INVUS PUBLIC EQUITIES, L.P.

By:  Invus Public Equities Advisors, LLC, its general
     partner

By:  /s/ Raymond Debbane
     -------------------------------------------------
     Name: Raymond Debbane
     Title: President


ARTAL INTERNATIONAL S.C.A.

By:  Artal International Management S.A., its managing
     partner

By:  /s/ Anne Goffard
     -------------------------------------------------
     Name: Anne Goffard
     Title: Managing Director


INVUS, L.P.

By:  Invus Advisors, L.L.C., its general partner

By:  /s/ Raymond Debbane
     -------------------------------------------------
     Name: Raymond Debbane
     Title: President


INVUS ADVISORS, L.L.C.

By:  /s/ Raymond Debbane
     -------------------------------------------------
     Name: Raymond Debbane
     Title: President


INVUS PUBLIC EQUITIES ADVISORS, LLC

By:  /s/ Raymond Debbane
     -------------------------------------------------
     Name: Raymond Debbane
     Title: President


ARTAL INTERNATIONAL MANAGEMENT S.A.

By:  /s/ Anne Goffard
     -------------------------------------------------
     Name: Anne Goffard
     Title: Managing Director


ARTAL GROUP S.A.

By:  /s/ Anne Goffard
     -------------------------------------------------
     Name: Anne Goffard
     Title: Authorized Person


WESTEND S.A.

By:  /s/ Pascal Minne
     -------------------------------------------------
     Name: Pascal Minne
     Title: Director


STICHTING ADMINISTRATIEKANTOOR
WESTEND

By:  /s/ Pascal Minne
     -------------------------------------------------
     Name: Pascal Minne
     Title: Sole Member of the Board


MR. PASCAL MINNE

By:  /s/ Pascal Minne
     -------------------------------------------------