Exhibit 99.1

    Antigenics' QS-21 Stimulon(R) Adjuvant Enters Phase 3 Clinical Trial of
 GlaxoSmithKline's Novel Cancer Immunotherapeutic in Non-Small Cell Lung Cancer

     NEW YORK--(BUSINESS WIRE)--June 5, 2007--Antigenics Inc. (NASDAQ: AGEN)
today announced that GlaxoSmithKline (GSK) has launched a Phase 3 clinical trial
evaluating its investigational MAGE-A3 Antigen-Specific Cancer Immunotherapeutic
(ASCI) in non-small cell lung cancer (NSCLC) - the largest trial ever conducted
in lung cancer treatment. GSK's MAGE-A3 ASCI is delivered as a purified
recombinant MAGE-A3 protein combined with GSK's proprietary adjuvant system
containing Antigenics' QS-21 Stimulon(R) adjuvant, for which Antigenics will
receive future milestone payments and product royalties upon successful
development and commercialization. According to the World Health Organization
(WHO), more than 1.3 million new cases of lung and bronchus cancer are diagnosed
each year worldwide, and approximately 35 percent to 50 percent of early NSCLC
expresses the MAGE-A3 antigen.(1)

     "QS-21 adjuvant is a critical vaccine component for our licensees, many of
whom are progressing drug candidates into late-stage development for the
prevention and treatment of major diseases," said Garo H. Armen, PhD, chairman
and CEO of Antigenics. "QS-21 is a profitable product for Antigenics and today's
announcement by GSK continues to underscore the substantial contribution to
Antigenics' future royalty income that could be generated from our adjuvant
franchise."

     QS-21 is a key component included in several of GSK's proprietary adjuvant
systems currently under development. Under the terms of the license and supply
agreements announced in July 2006, GSK will make payments contingent upon
successful milestone achievements, and will pay royalties to Antigenics on net
sales for a period of at least 10 years after first commercial sale.

     About QS-21 Stimulon Adjuvant

     Antigenics' QS-21 Stimulon adjuvant is one of the most widely tested
vaccine adjuvants under development. QS-21 has not only become a critical
component in the development of preventative vaccine formulations across a wide
variety of infectious diseases, but may also be essential in enabling a new
generation of therapeutic vaccines to treat cancer and degenerative disorders.
QS-21 is currently being evaluated in more than 20 vaccine indications, several
in late-stage clinical trials by Antigenics' licensees, including
GlaxoSmithKline, Elan, Acambis and Progenics. The first vaccine containing QS-21
could reach the market as early as 2009.

     About Antigenics

     Antigenics (NASDAQ: AGEN) is a biotechnology company working to develop
treatments for cancers and infectious diseases. The company's investigational
product portfolio includes Oncophage(R) (vitespen), a patient-specific
therapeutic cancer vaccine being evaluated in several indications; Aroplatin(TM)
(L-NDDP), a liposomal, third-generation platinum chemotherapeutic; AG-707, a
therapeutic vaccine for the treatment of genital herpes; and QS-21, an adjuvant
being evaluated by Antigenics' corporate partners in more than 20 indications,
several in late-stage clinical trials. For more information, please visit
antigenics.com.

     (1) World Health Organization- Cancer- Fact Sheet n 297 (February 2006)
(www.who.int)

     This press release contains forward-looking statements based on current
management expectations, including statements about the future Phase 3 clinical
trial in lung cancer using QS-21 by GSK, the future development of products
using QS-21, and the future payment of milestone payments and royalties in
connection with the development and commercialization of QS-21. These
forward-looking statements are subject to risks and uncertainties that could
cause actual results to differ materially. These risks and uncertainties
include, among others, Antigenics' dependence on its collaborative partners such
as GSK to successfully develop and commercialize products containing QS-21, the
scientific risk associated with the development of vaccines, the competitive
risk that other sources of competitive adjuvants could become available, and
difficulties or delays in manufacturing QS-21, and the risk factors described in
the Management's Discussion and Analysis of Financial Condition and Results of
Operations section of Antigenics' Form 10-Q as filed with the Securities and
Exchange Commission on May 10, 2007. Antigenics cautions investors not to place
considerable reliance on the forward-looking statements contained in this press
release. These statements speak only as of the date of this document, and
Antigenics undertakes no obligation to update or revise the statements. All
forward-looking statements are expressly qualified in their entirety by this
cautionary statement. Antigenics' business is subject to substantial risks and
uncertainties, including those identified above. When evaluating Antigenics'
business and securities, investors should give careful consideration to these
risks and uncertainties.


     CONTACT: Antigenics Inc.
              Media Relations
              Sunny Uberoi, 917-443-3325
              suberoi@antigenics.com
              or
              Investor Relations
              Robert Anstey, 800-962-2436
              ir@antigenics.com