AMENDMENT NO. 1 TO TERM NOTE

Exhibit 10.1 AMENDMENT NO. 1 TO TERM NOTE      This AMENDMENT NO. 1 (this " Amendment ") to the Term Note dated October 27, 2008, in the original principal amount of Three Million Dollars ($3,000,000) payable to the order of Clinical Data, Inc. (" CLDA ," and such Term Note referred to as the " Term Note ") is made as of this 12th day of January, 2009 by and between Avalon Pharmaceuticals, Inc. (" Avalon ") and CLDA.      WHEREAS, Avalon and CLDA desire to amend the Term Note to extend the Maturity Date, as that term is defined in Section 4 of the Term Note, from March 31, 2009 to April 30, 2009.      NOW, THEREFORE, in consideration of the mutual covenants and agreements set forth herein, in the Term Note and in the Note Purchase Agreement, as that term is defined in Section 1 of the Term Note, and for other good and valuable consideration, the receipt and adequacy of which is hereby acknowledged, the parties hereto agree as follows:       SECTION 1 . Amendment to the