13G Filing: Flynn James E and Xenoport Inc (XNPT)

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Page 13 of 14 SEC Filing

Exhibit A
Agreement
         The undersigned agree that this Schedule 13G, and all amendments thereto, relating to the Common Stock of XenoPort, Inc. shall be filed on behalf of the undersigned.
DEERFIELD MGMT, L.P.
By:  J.E. Flynn Capital, LLC, General Partner
By: /s/ Jonathan Isler
     Jonathan Isler, Attorney-In-Fact
DEERFIELD MANAGEMENT COMPANY, L.P.
By:  Flynn Management LLC, General Partner
By: /s/ Jonathan Isler
     Jonathan Isler, Attorney-In-Fact
DEERFIELD SPECIAL SITUATIONS FUND, L.P.
By:  Deerfield Mgmt, L.P., General Partner
By:  J.E. Flynn Capital, LLC, General Partner
By: /s/ Jonathan Isler
     Jonathan Isler, Attorney-In-Fact
JAMES E. FLYNN
 
/s/ Jonathan Isler
Jonathan Isler, Attorney-In-Fact

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