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Via Facsimile and U.S. Mail Mail Stop 4720                                                                                                   September 24, 2009 Garo H. Armen, Ph.D.  President and Chief Executive Officer  Antigenics Inc.  162 Fifth Avenue, Suite 900  New York, New York 10010

 Re: Antigenics Inc.
Form 10-K for the Fiscal Year Ended December 31, 2008 Filed March 16, 2009 File Number 000-29089

Dear Dr. Armen:
  We have reviewed your supplemental response and have the following additional comments.   In our comments, we ask you to provide us with information to better understand your disclosure. Where it requests yo u to revise disclosure, the information
you provide should show us what the revised disclosure will look like and identify the
annual or quarterly filing, as applicable, in which you intend to first include it. If you do
not believe that revised disc losure is necessary, explain the reason in your response.
After reviewing the information provided, we may raise additional comments and/or
request that you amend your filing.   Please understand that the purpose of our re view process is to assist you in your
compliance with the applicable disclosure  requirements and to  enhance the overall
disclosure in your filing.  We look forward to  working with you in these respects.  We
welcome any questions you may have about our  comments or on any other aspect of our
review.  Feel free to call us at the telephone numbers listed at the end of this letter.

Form 10-K for the Fiscal Year Ended December 31, 2008

Business, page 11

1. We note your response to Comment 1 a nd your statement that you have been
granted confidential treatment in relation to the information requested in our comment.  Please note that we do not gr ant confidential treatment for aggregate
amounts.  As such, please revise the propos ed disclosure for your agreements with
GSK and Elan to disclose the aggregate potential milestone payments and the percentage range of royalties  (for example: royalties between 10% and 15% of net
sales or low single digit royalties).

Garo H. Armen, Ph.D.
Antigenics Inc.  September 24, 2009 Page 2

In addition, it appears that the confidential tr eatment requests that you refer to
were not subject to review.  Please note th at we reserve the right to reconsider our
confidential treatment determinations.

Executive Compensation

 Annual Incentive Bonuses, page 108

2. We note your response to Comment 3 a nd Comments 4.  Please provide proposed
disclosure to be included  in your 2009 Form 10-K, which identifies how the level
of achievement with regard to the Comp any goals impacts the actual bonuses to
be paid to your NEOs.  For example, your 2008 disclosure should have described
the level of achievement of each of th e Company goals and indicated how the
respective levels of achie vement contributed to the Compensation Committee’s
decision to provide bonus payout s at 60% of target.  Your  proposed disclosure for
the 2009 Form 10-K should clearly indi cate how the achievement of your
Company goals will contribute to th e Compensation Committee’s determination
of the total bonus payout for 2009.  If there is a specific formula relating
achievement to award levels and/or we ightings for your Company goals, this
information should be provided.  In the alte rnative, if there is  no such formula or
weighting for the Company goals, your pr oposed disclosure should describe how
the Compensation Committee will make its  bonus payout determination.  Please
confirm that you will disclose how the compensation committee made its bonus payout determination.    Please also confirm that you will discuss the degree of achievement of corporate
goals and the NEO’s individual performan ce and the level of adjustment in the
event that the Compensation Committ ee adjusts an individual NEO’s bonus
payout based on individual performance.

*    *    *    *
 Please respond to these comments within  10 business days or tell us when you
will provide us with a response.  Please furnish a cover letter that keys your responses to
our comments and provide any requested inform ation.  Detailed letter s greatly facilitate
our review.  Please file y our letter on EDGAR under the form type label CORRESP.
  We urge all persons who are responsible for the accuracy and adequacy of the
disclosure in the filing to be certain that the filing includes all in formation required under
the Securities Exchange Act of 1934 and th at they have provided all information
investors require for an informed invest ment decision.  Since the company and its
management are in possession of all facts re lating to a company’s disclosure, they are
responsible for the accuracy and adequacy of the disclosures they have made.

Garo H. Armen, Ph.D.
Antigenics Inc.  September 24, 2009 Page 3
  In connection with responding to our co mments, please provide, in your letter, a
statement from the company acknowledging that:
• the company is responsible for the adequacy  and accuracy of the disclosure in the
filing;
• staff comments or changes to disclosure  in response to staff comments do not
foreclose the Commission from taking any action with respect to the filing; and
• the company may not assert staff comme nts as a defense in any proceeding
initiated by the Commission or any person under the federal secu rities laws of the
United States.

In addition, please be advise d that the Division of Enfo rcement has access to all
information you provide to the staff of the Divi sion of Corporation Fi nance in our review
of your filing or in response to our comment on your filing.
Please contact Bryan Pitko at  (202) 551-3203 with any quest ions.  In this regard,
please feel free to cont act me at (202) 551-3715.

Sincerely,

  Jeffrey Riedler,  Assistant Director