Shalini Sharp to Succeed Peter Thornton as Antigenics' Chief Financial Officer

"The decision to leave Antigenics has been a difficult one. It hasbeen both a pleasure and a privilege to work with Antigenics,surrounded by people of integrity and enormous energy and vision,"said Mr. Thornton.

"Peter has done an outstanding job in bringing Antigenics'financial capabilities to the top tier. Just as importantly, he isalso an individual of incomparable integrity and personal andmanagement qualities," said Garo H. Armen, PhD, chairman and CEO ofAntigenics. "Shalini has provided us with indispensable strategic andfinancial counsel over the years. With her impeccable credentials andknowledge of our company, we anticipate a particularly seamlesstransition. As a member of our executive management team, she willcontinue to contribute in her exceptional strategic capacity as wellas assuming the additional operational role with which she has workedso closely in the past."

Since joining Antigenics in 2003, Ms. Sharp has been a member ofthe senior management team, managing strategic planning, investorrelations, and financing and acquisition transactions. Prior to this,she was director of strategic planning at Elan Corporation, plc.,where she served as chief of staff to the chairman of the board duringthe restructuring process and drove to completion a number ofstrategic corporate and financial transactions. Ms. Sharp waspreviously a management consultant at McKinsey & Company, specializingin pharmaceuticals and medical devices. She has also worked ininvestment banking at Goldman, Sachs & Company, primarily in thehealth care field. She received her BA and MBA from HarvardUniversity.

Antigenics also announced that Christine Klaskin has been promotedfrom director to vice president of finance. Ms. Klaskin joinedAntigenics in 1996, after working as an audit manager at ArthurAndersen. A certified public accountant, she earned her Bachelor ofAccountancy from The George Washington University. Ms. Klaskin willreport in to Ms. Sharp.

About Antigenics

Antigenics (NASDAQ: AGEN) is working to develop treatments forcancers, infectious diseases and autoimmune disorders. The company'sinvestigational product portfolio includes Oncophage(R) (vitespen), apatient-specific therapeutic cancer vaccine being evaluated in severalindications; Aroplatin(TM), a liposomal, third-generation platinumchemotherapeutic; ATRA-IV, a liposomal retinoic acid; AG-707, atherapeutic vaccine for the treatment of genital herpes; AU-801, apreclinical program targeting autoimmune disorders; and QS-21, anadjuvant being evaluated by Antigenics' corporate partners in severallate-stage clinical trials. For more information, please visitwww.antigenics.com.

This press release contains forward-looking statements, includingstatements regarding the transition of responsibilities from Mr.Thornton to Ms. Sharp, and Ms. Sharp's anticipated futurecontributions to the company's strategy and operations. Thesestatements are subject to risks and uncertainties that could causeactual results to differ materially from those projected in theseforward-looking statements. Risks and uncertainties include, amongothers, the risk of disruption or loss of continuity that may beassociated with management transition; and the factors described underFactors That May Impact Future Results in the Management's Discussionand Analysis of Financial Condition and Results of Operations sectionof Antigenics' Form 10-Q as filed with the Securities and ExchangeCommission on May 12, 2006. Antigenics cautions investors not to placeconsiderable reliance on the forward-looking statements contained inthis press release. These statements speak only as of the date of thisdocument, and Antigenics undertakes no obligation to update or revisethe statements. All forward-looking statements are expressly qualifiedin their entirety by this cautionary statement. Antigenics' businessis subject to substantial risks and uncertainties, including thoseidentified above. When evaluating Antigenics' business and securities,investors should give careful consideration to these risks anduncertainties. The prior track record of Ms. Sharp does not assureAntigenics' future success.