Amendment No. 2 to Master Services Agreement

EXHIBIT 10.4

Amendment No. 2 to Master Services Agreement

This Amendment Number Two (this “Amendment 2”) is entered into this 22nd day of April, 2009 (the “Amendment 2 Effective Date”), by and between Antigenics Inc., a Delaware corporation having an address at 162 Fifth Avenue, Suite 900, New York, New York 10010 (the “Company”) and Raifarm Limited, a Cyprus registered company, having an address at Cyprus- Limassol 3030, 35 Thekla Lysioti street Eagle Star House, 6th floor, (each a “Party” and collectively the “Parties”). Capitalized terms not otherwise defined shall have the meaning set forth in the Agreement.

WHEREAS, Company and Raifarm Limited are parties to that certain Master Services Agreement with an effective date of May 23, 2007 (as amended from time to time, the “Agreement”); and

WHEREAS, the Parties now wish to amend the Agreement as set forth herein.

NOW THEREFORE, and in consideration of the premises and mutual covenants and agreements contained herein, and for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, the Parties hereby agree as follows:

[**] = Portions of this exhibit have been omitted pursuant to a confidential treatment request. An unpredicted version of this exhibit has been filed separately with the Commission.

IN WITNESS WHEREOF, the Parties each have caused this Amendment 2 to be executed by their duly respective authorized representative as of the Amendment 2 Effective Date.

[**] = Portions of this exhibit have been omitted pursuant to a confidential treatment request. An unpredicted version of this exhibit has been filed separately with the Commission.