Exhibit A
Agreement
The undersigned agree that this Schedule 13G and all amendments thereto,
relating to the Common Stock of ARENA PHARMACEUTICALS, INC. shall be filed on
behalf of the undersigned.
DEERFIELD CAPITAL, L.P.
By: X.X. Xxxxx Capital LLC,
General Partner
By: /s/ Xxxxxx Xxxxxx
----------------------------------------
Xxxxxx Xxxxxx, Authorized Signatory
DEERFIELD PARTNERS, L.P.
By: Deerfield Capital, L.P.
By: X.X. Xxxxx Capital LLC,
General Partner
By: /s/ Xxxxxx Xxxxxx
----------------------------------------
Xxxxxx Xxxxxx, Authorized Signatory
DEERFIELD MANAGEMENT COMPANY
By: Xxxxx Management LLC
General Partner
By: /s/ Xxxxxx Xxxxxx
----------------------------------------
Xxxxxx Xxxxxx, Authorized Signatory
DEERFIELD INTERNATIONAL LIMITED
By: Deerfield Management Company
By: Xxxxx Management LLC,
General Partner
By: /s/ Xxxxxx Xxxxxx
----------------------------------------
Xxxxxx Xxxxxx, Authorized Signatory
XXXXX X. XXXXX
/s/ Xxxxxx Xxxxxx
--------------------------------------------
Xxxxxx Xxxxxx, Attorney-in-Fact
Page 12 of 13
