Joint Filer Information

Names:
Deerfield Mgmt, L.P.,  Deerfield Management Company, L.P.,
Deerfield Partners, L.P., Deerfield International Master Fund, L.P.
   
Address:
780 Third Avenue, 37th Floor
New York, NY  10017
   
Designated Filer:
James E. Flynn
   
Issuer and Ticker Symbol:
Auxilium Pharmaceuticals, Inc.  [AUXL]
   
Date of Earliest Transaction
Required to be Reported:
January 29, 2015
 
The undersigned, Deerfield Mgmt, L.P.,  Deerfield Management Company, L.P., Deerfield Partners, L.P. and Deerfield International Master Fund, L.P., are jointly filing the attached Statement of Changes in Beneficial Ownership on Form 4 with James E. Flynn with respect to the beneficial ownership of securities of Auxilium Pharmaceuticals, Inc.
 
Signatures:
  
DEERFIELD MGMT, L.P.
 
By:  J.E. Flynn Capital, LLC, General Partner
 
By: /s/ Jonathan Isler
       Jonathan Isler, Attorney-In-Fact
 
DEERFIELD PARTNERS, 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
   
DEERFIELD MANAGEMENT COMPANY, L.P.
 
By:  Flynn Management LLC, General Partner
 
By: /s/ Jonathan Isler
       Jonathan Isler, Attorney-In-Fact
DEERFIELD INTERNATIONAL MASTER 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