Exhibit 99.1

                Antigenics Reports Second Quarter 2004
               Financial Results and Recent Highlights

    Business Editors/Health/Medical Writers
    BIOWIRE2K

    NEW YORK--(BUSINESS WIRE)--July 22, 2004--Antigenics Inc. (NASDAQ:
AGEN) reported results today for the quarter ended June 30, 2004. The
company incurred a net loss attributable to common stockholders of
$3.3 million, or $0.07 per share, basic and diluted, for the second
quarter of 2004. This is compared with a net loss attributable to
common stockholders in the second quarter of 2003 of $16.6 million, or
$0.42 per share, basic and diluted. Research and development costs
were $10.9 million in the second quarter of 2004, compared with $11.8
million for the same period in 2003. The reduced net loss in the
quarter ended June 30, 2004, reflects the recognized gain of $14
million from the sale of the company's manufacturing rights for feline
leukemia virus vaccine. In accordance with accounting principles
generally accepted in the United States, this business has been
accounted for as a discontinued operation in the condensed
consolidated statements of operations data presented below in both the
current and prior periods. For the quarter ended June 30, 2004, the
company incurred a loss from continuing operations of $17.0 million or
$0.38 per share, basic and diluted. This is compared with a loss from
continuing operations in the second quarter of 2003 of $16.8 million
or $0.43 per share, basic and diluted. Cash, cash equivalents and
short-term investments equaled $117.5 million on June 30, 2004.
    "We continue with our steady progress towards completion of our
Phase 3 trials, as well as a number of very important
precommercialization activities," said Garo H. Armen, PhD, chairman
and CEO of Antigenics. "In addition, we have made important
advancements in our next-generation Oncophage technology, which has
the potential to significantly expand the types of cancers we
address."

    Recent Highlights

    --  At the 40th annual meeting of the American Society of Clinical
        Oncology (ASCO), findings from two clinical trials of
        Oncophage(R) (HSPPC-96) were presented. Investigators from the
        Istituto Nazionale Tumori in Milan, Italy, presented findings
        from a Phase 2 trial of Oncophage as part of combination
        treatment for metastatic melanoma. In addition, demographic
        data were published from the company's Phase 3 trial of
        Oncophage in renal cell carcinoma.

    --  A Type A Meeting was held with the medical review team of the
        US Food and Drug Administration (FDA) to discuss the Oncophage
        product registration strategy for renal cell carcinoma. The
        agency expressed agreement with the proposed registration plan
        as presented by Antigenics.

    --  In advance of filing an investigational new drug (IND)
        application for AG-707 for genital herpes, a pre-IND meeting
        was held with the FDA. We expect to submit an IND in the next
        several months and commence enrollment shortly thereafter.

    --  Significant progress has been made in the development of the
        next-generation Oncophage program. Antigenics has developed a
        method to increase the yield using a new process. This
        technology, when implemented, will result in a substantial
        increase in yields of autologous product, allowing for much
        smaller tumor samples to be processed for manufacturing of
        vaccine.

    --  A new Aroplatin(TM) formulation has been identified that will
        offer increased product stability, activity and scalability
        for commercialization. Preclinical testing will conclude later
        this year, allowing for further clinical development to
        commence.

    --  In June, Peter Thornton was appointed as Chief Financial
        Officer and Senior Vice President.

    Conference Call Information

    Antigenics executives will host a conference call at 11:00 a.m. ET
today. To access the live call, dial 888.271.9082 (domestic) or
706.679.7741 (international); the access code is 8680871. The call
will also be webcast and will be accessible from the company's website
at www.antigenics.com/webcast/. A replay will be available
approximately two hours after the call through midnight ET on August
5, 2004. The replay number is 800.642.1687 (domestic) or 706.645.9291
(international), and the access code is 8680871. The replay will also
be available on the company's website approximately two hours after
the live call.

    About Antigenics

    Antigenics is working to develop personalized immunotherapeutics
and revolutionary treatments for cancers, infectious diseases and
autoimmune disorders. The company's lead product candidate is
Oncophage, a late-stage, personalized cancer vaccine being evaluated
in several indications, including renal cell carcinoma and metastatic
melanoma. Antigenics' portfolio also includes AG-858, a personalized
cancer vaccine in Phase 2 development; Aroplatin, a Phase 2 liposomal
chemotherapeutic; and AG-702/AG-707, a Phase 1 genital herpes program.
For more information about Antigenics, please visit
www.antigenics.com.

    This press release contains forward-looking statements, including
statements regarding our ability to develop a next-generation
Oncophage; that a next-generation Oncophage will expand the types of
cancer we are able to address; potential commercialization of
Oncophage; and future clinical development of Oncophage. These
statements are subject to risks and uncertainties that could cause
actual results to differ materially from those projected in these
forward-looking statements. Risks and uncertainties relating to
commercialization of Oncophage include, among others, the results from
ongoing Phase 3 clinical trials; the need for and extent of additional
clinical trials; the need to resolve product characterization issues;
whether any regulatory agencies will consider the ongoing Phase 3
clinical trials pivotal for purposes of product registration; and the
factors described in the company's periodic filings with the
Securities and Exchange Commission. Risks and uncertainties regarding
development of next-generation Oncophage and other product candidates
include the ability to demonstrate that the product candidates are
safe, effective and well characterized; to manufacture the product
candidates; to enroll sufficient patients in clinical trials; and to
obtain regulatory approvals. Please see the disclosure under the
heading "Factors That May Impact Future Results" in the Management's
Discussion and Analysis of Financial Condition and Results of
Operations section of the Antigenics Annual Report on Form 10-Q for
the quarter ended March 31, 2004, for a more complete discussion of
these and other risk factors. 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.


              Summary Consolidated Financial Information

         Condensed Consolidated Statements of Operations Data
                 (in thousands, except per share data)
                              (unaudited)

                            Three months ended     Six months ended
                                  June 30,              June 30,
                              2004       2003       2004       2003
                           ---------- ---------- ---------- ----------

Revenue                     $    187   $     33   $    296   $    928

Operating expenses:
 Research and development     10,879     11,757     21,825     21,878
 General and administrative    6,576      5,351     12,121      9,954

                           ---------- ---------- ---------- ----------

Operating loss               (17,268)   (17,075)   (33,650)   (30,904)

 Other income, net               225        317        377        651

                           ---------- ---------- ---------- ----------
Loss from continuing
 operations                  (17,043)   (16,758)   (33,273)   (30,253)

 Income from discontinued
  operations (including gain
  on disposal of $14 million
  in 2004)                    13,960        139     13,034        143
                           ---------- ---------- ---------- ----------
Net Loss                      (3,083)   (16,619)   (20,239)   (30,110)

 Dividends on Series A
  Convertible Preferred
   Stock                        (198)         -       (395)         -
                           ---------- ---------- ---------- ----------
Net loss attributable to
 common stockholders        $ (3,281) $ (16,619)  $(20,634)  $(30,110)
                           ========== ========== ========== ==========

Per common share data:
 Loss from continuing
  operations, basic and
  diluted                   $  (0.38) $   (0.43)  $  (0.76)  $  (0.79)
 Net loss attributable to
  common stockholders,
  basic and diluted         $  (0.07) $   (0.42)  $  (0.47)  $  (0.78)
 Weighted average number of
  common shares outstanding,
  basic and diluted           45,068     39,385     43,923     38,485


                    Consolidated Balance Sheet data
                            (in thousands)
                              (unaudited)

                            June 30,   Dec. 31,
                              2004       2003
                           ---------- ----------

Cash, cash equivalents and
 short-term investments     $117,483   $ 89,478
Total assets                 167,830    140,080
Total stockholders' equity   139,185    105,246



    CONTACT: Antigenics Inc.
             Investor Relations
             Jack Howarth, 212-994-8244
             jhowarth@antigenics.com
              or
             Corporate Communications
             Sunny Uberoi, 212-994-8206
             suberoi@antigenics.com