content: <PAGE>   1
  
        As filed with the Securities and Exchange Commission on June 29, 2000
  
                                                             REGISTRATION NO. 333-
  
                         SECURITIES AND EXCHANGE COMMISSION
                               Washington, D. C. 20549
  
  
                                      FORM S-8
                            REGISTRATION STATEMENT UNDER
                             THE SECURITIES ACT OF 1933
  
  
                                   ANTIGENICS INC.
               (Exact Name of Registrant as Specified in its Charter)
  
  <TABLE>
  <S>                                                           <C>
                   DELAWARE                                     06-1562417
  (State or Other Jurisdiction of Incorporation)  (I.R.S. Employer Identification No.)
  </TABLE>
  
               630 FIFTH AVENUE, SUITE 2100, NEW YORK, NEW YORK 10111
                      (Address of Principal Executive Offices)
  
  
                             1999 EQUITY INCENTIVE PLAN
                              (Full Title of the Plan)
  
                                GARO H. ARMEN, PH.D.
                               Chief Executive Officer
                                   Antigenics Inc.
                            630 Fifth Avenue, Suite 2100
                              New York, New York 10111
                                   (212) 332-4774
              (Name, Address and Telephone Number of Agent for Service)
  
                                   with copies to:
  
                                MICHAEL LYTTON, ESQ.
                                 Palmer & Dodge LLP
                                  One Beacon Street
                             Boston, Massachusetts 02108
                                   (617) 573-0100
  
                           CALCULATION OF REGISTRATION FEE
  <TABLE>
  <CAPTION>
  -----------------------------------------------------------------------------------------------------------------------
                                                                Proposed maximum     Proposed maximum       Amount of
  Title of each class of securities to be     Amount to be     offering price per   aggregate offering    registration
                 registered                   registered(1)         share(2)             price(2)              fee
  -----------------------------------------------------------------------------------------------------------------------
  
  <S>           <C>                         <C>                 <C>                <C>                 <C>
  Common Stock, $0.01 par value             4,800,000 shares        $14.516            $69,676,800          $18,395
  -----------------------------------------------------------------------------------------------------------------------
  </TABLE>
  
  (1)  Pursuant to Rule 416 under the Securities Act of 1933, to the extent
       additional shares of our common stock may be issued or issuable as a result
       of a stock split or other distribution declared at any time by the Board of
       Directors while this registration statement is in effect, this registration
       statement is hereby deemed to cover all such additional shares common
       stock.
  (2)  Estimated solely for the purpose of determining the registration fee and
       computed pursuant to Rule 457(h)(1). The proposed maximum offering price
       per share indicated equals the last per share sale price of Antigenics
       common stock on June 22, 2000 as reported by the Nasdaq National Market.
  
  
  
  <PAGE>   2
  
  
                                       PART II
  
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.
  
           The following documents previously filed with the Securities and
  Exchange Commission are incorporated by reference herein and shall be deemed as
  part hereof:
  
           (a)      the prospectus contained in our registration statement on Form
                    S-1 (File No. 333-37820) filed under the Securities Act of
                    1933, as amended, (the "Securities Act") on May 25, 2000, as
                    it may be amended from time to time;
  
           (b)      our quarterly report on Form 10-Q for the quarter ended March
                    31, 2000 filed under the Securities Exchange Act of 1934, as
                    amended, (the "Exchange Act") on May 15, 2000 (File No.
                    000-29089); and
  
           (c)      the description of our common stock contained in our
                    Registration Statement on Form 8-A filed on January 24, 2000,
                    including any amendment or report filed hereafter for the
                    purpose of updating such description.
  
           All documents filed after the date of this registration statement
  pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act of 1934 and
  prior to the filing of a post-effective amendment that indicates that all shares
  of common stock offered hereunder have been sold or that deregisters all shares
  of common stock remaining unsold shall be deemed to be incorporated by reference
  herein and to be a part hereof from the date of the filing of such reports and
  documents.
  
  ITEM 4.  DESCRIPTION OF SECURITIES.
  
           Not applicable.
  
  ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.
  
           Not applicable.
  
  ITEM 6.  INDEMNIFICATION OF OFFICERS AND DIRECTORS.
  
           Section 145 of the Delaware General Corporation Law provides that a
  corporation may indemnify any person who was or is a party or is threatened to
  be made a party to any threatened, pending or completed action, suit or
  proceeding, whether civil, criminal, administrative or investigative, other than
  an action by or in the right of the corporation, by reason of the fact that the
  person is or was a director, officer, employee or agent of the corporation or is
  or was serving at the corporation's request as a director, officer, employee or
  agent of another corporation, partnership, joint venture, trust or other
  enterprise, against expenses, including attorneys' fees, judgments, fines and
  amounts paid in settlement actually and reasonably incurred by the person in
  connection with the action, suit or proceeding if the person acted in good faith
  and in a manner the person reasonably believed to be in or not opposed to the
  best interests of the corporation, and, with respect to any criminal action or
  proceeding, had no reasonable cause to believe the person's conduct was
  unlawful. The power to indemnify applies to actions brought by or in the right
  of the corporation as well, but only to the extent of expenses, including
  attorneys' fees but excluding judgments, fines and amounts paid in settlement,
  actually and reasonably incurred by the person in connection with the defense or
  settlement of the action or suit. In these actions no indemnification shall be
  made in the event of any adjudication of negligence or misconduct in the
  performance of his duties to the corporation, unless a court believes that in
  light of all the circumstances indemnification should apply.
  
           Article V of Antigenics' By-laws provides that Antigenics shall, to the
  extent legally permitted, indemnify each person who was or is a party or is
  threatened to be made a party to any threatened, pending or completed action,
  suit or proceeding by reason of the fact that he is or was, or has agreed to
  become, a director or officer of
  
  
                                         2
  
  <PAGE>   3
  
  Antigenics, or is or was serving, or has agreed to serve, at the request of
  Antigenics, as a director, officer or trustee of, or in a similar capacity with,
  another corporation, partnership, joint venture, trust or other enterprises. The
  indemnification provided for in Article V is expressly not exclusive of any
  other rights to which those seeking indemnification may be entitled under any
  law, agreement or vote of stockholders or disinterested directors or otherwise,
  and shall inure to the benefit of the heirs, executors and administrators of
  such persons.
  
           Section 145(g) of the Delaware General Corporation Law and Article V of
  By-laws of Antigenics provide that the company shall have the power to purchase
  and maintain insurance on behalf of its officers, directors, employees and
  agents, against any liability asserted against and incurred by such persons in
  any such capacity.
  
           Antigenics has entered into indemnification agreements with each of its
  directors and executive officers and has obtained insurance covering its
  directors and officers against losses and insuring Antigenics against certain of
  its obligations to indemnify its directors and officers.
  
           Section 102(b)(7) of the General Corporation Law of the State of
  Delaware provides that a corporation may eliminate or limit the personal
  liability of a director to the corporation or its stockholders for monetary
  damages for breach of fiduciary duty as a director, provided that such
  provisions shall not eliminate or limit the liability of a director (i) for any
  breach of the director's duty of loyalty to the corporation or its stockholders,
  (ii) for acts or omissions not in good faith or which involve intentional
  misconduct or a knowing violation of law, (iii) under Section 174 of the General
  Corporation Law of the State of Delaware, or (iv) for any transaction from which
  the director derived an improper personal benefit. No such provision shall
  eliminate or limit the liability of a director for any act or omission occurring
  prior to the date when such provision becomes effective.
  
           Pursuant to the Delaware General Corporation Law, Section 7 of Article
  FIFTH of the Certificate of Incorporation of Antigenics eliminates a director's
  personal liability for monetary damages to Antigenics and its stockholders for
  breach of fiduciary duty as a director, except in circumstances involving a
  breach of the director's duty of loyalty to Antigenics or its stockholders, acts
  or omissions not in good faith, intentional misconduct, knowing violations of
  the law, self-dealing or the unlawful payment of dividends or repurchase of
  stock.
  
  ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.
  
           Not applicable.
  
  ITEM 8.  EXHIBITS.
  
           See Exhibit Index immediately following signature pages.
  
  ITEM 9.  UNDERTAKINGS.
  
           (a)      The undersigned registrant hereby undertakes:
  
                    (1) To file, during any period in which offers or sales are
  being made, a post-effective amendment to this registration statement:
  
                             (i) To include any prospectus required by Section 10
  (a)(3) of the Securities Act of 1933;
  
                             (ii) To reflect in the prospectus any facts or events
  arising after the effective date of this registration statement (or the most
  recent post-effective amendment thereof) which, individually or in the
  aggregate, represents a fundamental change in the information set forth in this
  registration statement;
  
                             (iii) To include any material information with
  respect to the plan of distribution not previously disclosed in this
  registration statement or any material change to such information in this
  registration statement; provided, however, that paragraphs (a) (1) (i) and (a)
  (1) (ii) do not apply if the information required to be included in a
  post-effective amendment by those paragraphs is contained in periodic reports
  filed by the Registrant
  
  
  
                                         3
  <PAGE>   4
  
  pursuant to Section 13 or Section 15(d) of the Exchange Act of 1934 that are
  incorporated by reference in this Registration Statement.
  
                    (2) That, for the purpose of determining any liability under
  the Securities Act of 1933, each such post-effective amendment shall be deemed
  to be a new registration statement relating to the securities offered therein,
  and the offering of such securities at that time shall be deemed to be the
  initial bona fide offering thereof.
  
                    (3) To remove from registration by means of a post-effective
  amendment any of the securities being registered which remain unsold at the
  termination of the offering.
  
           (b) The undersigned registrant hereby undertakes that, for purposes of
  determining any liability under the Securities Act of 1933, each filing of the
  registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
  Exchange Act of 1934 that is incorporated by reference in this registration
  statement shall be deemed to be a new registration statement relating to the
  securities offered therein and the offering of such securities at that time
  shall be deemed to be initial bona fide offering thereof.
  
           (c) Insofar as indemnification for liabilities arising under the
  Securities Act of 1933 may be permitted to directors, officers and controlling
  persons of the registrant pursuant to the provisions referred to in Item 6
  hereof, or otherwise, the registrant has been advised that in the opinion of the
  Securities and Exchange Commission such indemnification is against public policy
  as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In
  the event that a claim for indemnification against such liabilities (other than
  the payment by the registrant of expenses incurred or paid by a directors,
  officer or controlling person of the registrant in the successful defense of any
  action, suit or proceeding) is asserted by such director, officer, or
  controlling person in connection with the securities being registered, the
  registrant will, unless in the opinion of its counsel the matter has been
  settled by controlling precedent, submit to a court of appropriate jurisdiction
  the question whether such indemnification by it is against public policy as
  expressed in the Securities Act of 1933 and will be governed by the final
  jurisdiction of such issue.
  
  
  
                                         4
  <PAGE>   5
  
                                     SIGNATURES
  
  Pursuant to the requirements of the Securities Act of 1933, the Registrant
  certifies that it has duly caused this Registration Statement to be signed on
  its behalf by the undersigned, thereunto duly authorized, in the Town of Woburn,
  Commonwealth of Massachusetts, as of June 29, 2000.
  
                                          ANTIGENICS INC.
  
                                          By: /s/ Garo H. Armen, Ph.D.
                                             ----------------------------------
                                             Garo H. Armen, Ph.D.
                                             Chief Executive Officer and
                                             Chairman of the Board of Directors
  
                                  POWER OF ATTORNEY
  
  We, the undersigned officers and directors of Antigenics Inc., hereby severally
  constitute and appoint Garo H. Armen, Ph.D., Edward Brodsky and Michael Lytton
  and each of them singly, our true and lawful attorneys-in-fact, with full power
  to them in any and all capacities, to sign any and all amendments to this
  Registration Statement on Form S-8 (including any post-effective amendments
  thereto), and to file the same, with exhibits thereto and other documents in
  connection therewith, with the Securities and Exchange Commission, hereby
  ratifying and confirming all that each of said attorneys-in-fact may do or cause
  to be done by virtue hereof.
  
  Pursuant to the requirements of the Securities Act of 1933, this Registration
  Statement has been signed below by the following persons in the capacities and
  as of the dates indicated.
  
  <TABLE>
  <CAPTION>
  SIGNATURE                                              TITLE                                DATE
  
  <S>                                                    <C>                                  <C>
    /s/  Garo H. Armen, Ph.D.                            Chief Executive Officer and          June 29, 2000
  -------------------------------------                  Chairman of the Board of
  Garo H. Armen, Ph.D.                                   Directors (Principal Executive
                                                         Officer and Principal Financial
                                                         and Accounting Officer)
  
    /s/  Pramod Srivastava, Ph.D.                        Director                             June 29, 2000
  -------------------------------------
  Pramod Srivastava, Ph.D.
  
    /s/  Noubar Afeyan, Ph.D.                            Director                             June 29, 2000
  -------------------------------------
  Noubar Afeyan, Ph.D.
  
    /s/  Edward Brodsky                                  Director                             June 29, 2000
  -------------------------------------
  Edward Brodsky
  
    /s/  Gamil de Chadarevian                            Director                             June 29, 2000
  -------------------------------------
  Gamil de Chadarevian
  
                                                         Director
  -------------------------------------
  Tom Dechaene
  
    /s/  Donald Panoz                                    Director                             June 29, 2000
  -------------------------------------
  Donald Panoz
  
    /s/  Martin Taylor                                   Director                             June 29, 2000
  -------------------------------------
  Martin Taylor
  </TABLE>
  
  
  
  
                                         5
  <PAGE>   6
  
  
  
  
  
                                    EXHIBIT INDEX
  
  
         EXHIBIT
          NUMBER        DESCRIPTION
  
           4.1      Certificate of Incorporation of Antigenics Inc. Filed as
                    Exhibit 3.1 to our Registration Statement on Form S-1 (File
                    No. 333-91747) and incorporated herein by reference.
  
           4.2      By-laws of Antigenics Inc. Filed as Exhibit 3.2 to our
                    Registration Statement on Form S-1 (File No. 333-91747) and
                    incorporated herein by reference.
  
           4.3      Form of Warrant to purchase Common Stock, together with a list
                    of holders. Filed as Exhibit 4.1 to our Registration Statement
                    on Form S-1 (File No. 333-91747) and incorporated herein by
                    reference.
  
           4.4      Form of Subscription Agreement, as amended, together with a
                    list of parties thereto. Filed as Exhibit 4.2 to our
                    Registration Statement on Form S-1 (File No. 333-91747) and
                    incorporated herein by reference.
  
           5.1      Opinion of Palmer & Dodge LLP. Filed herewith.
  
          23.1      Consent of KPMG LLP. Filed herewith.
  
          23.2      Consent of Palmer & Dodge LLP. Included in the opinion filed
                    as Exhibit 5.1.
  
          24.1      Power of Attorney. Included on the signature page hereto.
  
          99.1      1999 Equity Incentive Plan. Filed as Appendix A to our Proxy
                    Statement on Schedule 14A filed on April 24, 2000 (File No.
                    000-29089) and incorporated herein by reference.
metadata_documents: [{"type": "S-8", "sequence": "1", "filename": "s-8.txt", "description": "ANTIGENICS INC.", "secsgml_size_bytes": 18949}]
metadata_filer: {"company-data": {"conformed-name": "ANTIGENICS INC /DE/", "cik": "0001098972", "assigned-sic": "2836", "irs-number": "061562417", "state-of-incorporation": "DE", "fiscal-year-end": "1231"}, "filing-values": {"form-type": "S-8", "act": "33", "file-number": "333-40442", "film-number": "665212"}, "business-address": {"street1": "630 FIFTH AVENUE SUITE 2170", "city": "NEW YORK", "state": "NY", "zip": "10111", "phone": "2123324774"}, "mail-address": {"street1": "630 FIFTH AVENUE SUITE 2170", "city": "NEW YORK", "state": "NY", "zip": "10111"}}
text: 1
  
        As filed with the Securities and Exchange Commission on June 29, 2000
  
                                                             REGISTRATION NO. 333-
  
                         SECURITIES AND EXCHANGE COMMISSION
                               Washington, D. C. 20549
  
                                      FORM S-8
                            REGISTRATION STATEMENT UNDER
                             THE SECURITIES ACT OF 1933
  
                                   ANTIGENICS INC.
               (Exact Name of Registrant as Specified in its Charter)
  DELAWARE                                     06-1562417
  (State or Other Jurisdiction of Incorporation)  (I.R.S. Employer Identification No.)
  630 FIFTH AVENUE, SUITE 2100, NEW YORK, NEW YORK 10111
                      (Address of Principal Executive Offices)
  
                             1999 EQUITY INCENTIVE PLAN
                              (Full Title of the Plan)
  
                                GARO H. ARMEN, PH.D.
                               Chief Executive Officer
                                   Antigenics Inc.
                            630 Fifth Avenue, Suite 2100
                              New York, New York 10111
                                   (212) 332-4774
              (Name, Address and Telephone Number of Agent for Service)
  
                                   with copies to:
  
                                MICHAEL LYTTON, ESQ.
                                 Palmer & Dodge LLP
                                  One Beacon Street
                             Boston, Massachusetts 02108
                                   (617) 573-0100
  
                           CALCULATION OF REGISTRATION FEE
  -----------------------------------------------------------------------------------------------------------------------
                                                                Proposed maximum     Proposed maximum       Amount of
  Title of each class of securities to be     Amount to be     offering price per   aggregate offering    registration
                 registered                   registered(1)         share(2)             price(2)              fee
  -----------------------------------------------------------------------------------------------------------------------
  Common Stock, $0.01 par value             4,800,000 shares        $14.516            $69,676,800          $18,395
  -----------------------------------------------------------------------------------------------------------------------
  (1)  Pursuant to Rule 416 under the Securities Act of 1933, to the extent
       additional shares of our common stock may be issued or issuable as a result
       of a stock split or other distribution declared at any time by the Board of
       Directors while this registration statement is in effect, this registration
       statement is hereby deemed to cover all such additional shares common
       stock.
  (2)  Estimated solely for the purpose of determining the registration fee and
       computed pursuant to Rule 457(h)(1). The proposed maximum offering price
       per share indicated equals the last per share sale price of Antigenics
       common stock on June 22, 2000 as reported by the Nasdaq National Market.
  2
  
                                       PART II
  
                 INFORMATION REQUIRED IN THE REGISTRATION STATEMENT
  
  ITEM 3.  INCORPORATION OF DOCUMENTS BY REFERENCE.
  
           The following documents previously filed with the Securities and
  Exchange Commission are incorporated by reference herein and shall be deemed as
  part hereof:
  
           (a)      the prospectus contained in our registration statement on Form
                    S-1 (File No. 333-37820) filed under the Securities Act of
                    1933, as amended, (the "Securities Act") on May 25, 2000, as
                    it may be amended from time to time;
  
           (b)      our quarterly report on Form 10-Q for the quarter ended March
                    31, 2000 filed under the Securities Exchange Act of 1934, as
                    amended, (the "Exchange Act") on May 15, 2000 (File No.
                    000-29089); and
  
           (c)      the description of our common stock contained in our
                    Registration Statement on Form 8-A filed on January 24, 2000,
                    including any amendment or report filed hereafter for the
                    purpose of updating such description.
  
           All documents filed after the date of this registration statement
  pursuant to Sections 13(a), 13(c), 14 and 15(d) of the Exchange Act of 1934 and
  prior to the filing of a post-effective amendment that indicates that all shares
  of common stock offered hereunder have been sold or that deregisters all shares
  of common stock remaining unsold shall be deemed to be incorporated by reference
  herein and to be a part hereof from the date of the filing of such reports and
  documents.
  
  ITEM 4.  DESCRIPTION OF SECURITIES.
  
           Not applicable.
  
  ITEM 5.  INTERESTS OF NAMED EXPERTS AND COUNSEL.
  
           Not applicable.
  
  ITEM 6.  INDEMNIFICATION OF OFFICERS AND DIRECTORS.
  
           Section 145 of the Delaware General Corporation Law provides that a
  corporation may indemnify any person who was or is a party or is threatened to
  be made a party to any threatened, pending or completed action, suit or
  proceeding, whether civil, criminal, administrative or investigative, other than
  an action by or in the right of the corporation, by reason of the fact that the
  person is or was a director, officer, employee or agent of the corporation or is
  or was serving at the corporation's request as a director, officer, employee or
  agent of another corporation, partnership, joint venture, trust or other
  enterprise, against expenses, including attorneys' fees, judgments, fines and
  amounts paid in settlement actually and reasonably incurred by the person in
  connection with the action, suit or proceeding if the person acted in good faith
  and in a manner the person reasonably believed to be in or not opposed to the
  best interests of the corporation, and, with respect to any criminal action or
  proceeding, had no reasonable cause to believe the person's conduct was
  unlawful. The power to indemnify applies to actions brought by or in the right
  of the corporation as well, but only to the extent of expenses, including
  attorneys' fees but excluding judgments, fines and amounts paid in settlement,
  actually and reasonably incurred by the person in connection with the defense or
  settlement of the action or suit. In these actions no indemnification shall be
  made in the event of any adjudication of negligence or misconduct in the
  performance of his duties to the corporation, unless a court believes that in
  light of all the circumstances indemnification should apply.
  
           Article V of Antigenics' By-laws provides that Antigenics shall, to the
  extent legally permitted, indemnify each person who was or is a party or is
  threatened to be made a party to any threatened, pending or completed action,
  suit or proceeding by reason of the fact that he is or was, or has agreed to
  become, a director or officer of
  
                                         2
  3
  
  Antigenics, or is or was serving, or has agreed to serve, at the request of
  Antigenics, as a director, officer or trustee of, or in a similar capacity with,
  another corporation, partnership, joint venture, trust or other enterprises. The
  indemnification provided for in Article V is expressly not exclusive of any
  other rights to which those seeking indemnification may be entitled under any
  law, agreement or vote of stockholders or disinterested directors or otherwise,
  and shall inure to the benefit of the heirs, executors and administrators of
  such persons.
  
           Section 145(g) of the Delaware General Corporation Law and Article V of
  By-laws of Antigenics provide that the company shall have the power to purchase
  and maintain insurance on behalf of its officers, directors, employees and
  agents, against any liability asserted against and incurred by such persons in
  any such capacity.
  
           Antigenics has entered into indemnification agreements with each of its
  directors and executive officers and has obtained insurance covering its
  directors and officers against losses and insuring Antigenics against certain of
  its obligations to indemnify its directors and officers.
  
           Section 102(b)(7) of the General Corporation Law of the State of
  Delaware provides that a corporation may eliminate or limit the personal
  liability of a director to the corporation or its stockholders for monetary
  damages for breach of fiduciary duty as a director, provided that such
  provisions shall not eliminate or limit the liability of a director (i) for any
  breach of the director's duty of loyalty to the corporation or its stockholders,
  (ii) for acts or omissions not in good faith or which involve intentional
  misconduct or a knowing violation of law, (iii) under Section 174 of the General
  Corporation Law of the State of Delaware, or (iv) for any transaction from which
  the director derived an improper personal benefit. No such provision shall
  eliminate or limit the liability of a director for any act or omission occurring
  prior to the date when such provision becomes effective.
  
           Pursuant to the Delaware General Corporation Law, Section 7 of Article
  FIFTH of the Certificate of Incorporation of Antigenics eliminates a director's
  personal liability for monetary damages to Antigenics and its stockholders for
  breach of fiduciary duty as a director, except in circumstances involving a
  breach of the director's duty of loyalty to Antigenics or its stockholders, acts
  or omissions not in good faith, intentional misconduct, knowing violations of
  the law, self-dealing or the unlawful payment of dividends or repurchase of
  stock.
  
  ITEM 7.  EXEMPTION FROM REGISTRATION CLAIMED.
  
           Not applicable.
  
  ITEM 8.  EXHIBITS.
  
           See Exhibit Index immediately following signature pages.
  
  ITEM 9.  UNDERTAKINGS.
  
           (a)      The undersigned registrant hereby undertakes:
  
                    (1) To file, during any period in which offers or sales are
  being made, a post-effective amendment to this registration statement:
  
                             (i) To include any prospectus required by Section 10
  (a)(3) of the Securities Act of 1933;
  
                             (ii) To reflect in the prospectus any facts or events
  arising after the effective date of this registration statement (or the most
  recent post-effective amendment thereof) which, individually or in the
  aggregate, represents a fundamental change in the information set forth in this
  registration statement;
  
                             (iii) To include any material information with
  respect to the plan of distribution not previously disclosed in this
  registration statement or any material change to such information in this
  registration statement; provided, however, that paragraphs (a) (1) (i) and (a)
  (1) (ii) do not apply if the information required to be included in a
  post-effective amendment by those paragraphs is contained in periodic reports
  filed by the Registrant
  
                                         3
  4
  
  pursuant to Section 13 or Section 15(d) of the Exchange Act of 1934 that are
  incorporated by reference in this Registration Statement.
  
                    (2) That, for the purpose of determining any liability under
  the Securities Act of 1933, each such post-effective amendment shall be deemed
  to be a new registration statement relating to the securities offered therein,
  and the offering of such securities at that time shall be deemed to be the
  initial bona fide offering thereof.
  
                    (3) To remove from registration by means of a post-effective
  amendment any of the securities being registered which remain unsold at the
  termination of the offering.
  
           (b) The undersigned registrant hereby undertakes that, for purposes of
  determining any liability under the Securities Act of 1933, each filing of the
  registrant's annual report pursuant to Section 13(a) or Section 15(d) of the
  Exchange Act of 1934 that is incorporated by reference in this registration
  statement shall be deemed to be a new registration statement relating to the
  securities offered therein and the offering of such securities at that time
  shall be deemed to be initial bona fide offering thereof.
  
           (c) Insofar as indemnification for liabilities arising under the
  Securities Act of 1933 may be permitted to directors, officers and controlling
  persons of the registrant pursuant to the provisions referred to in Item 6
  hereof, or otherwise, the registrant has been advised that in the opinion of the
  Securities and Exchange Commission such indemnification is against public policy
  as expressed in the Securities Act of 1933 and is, therefore, unenforceable. In
  the event that a claim for indemnification against such liabilities (other than
  the payment by the registrant of expenses incurred or paid by a directors,
  officer or controlling person of the registrant in the successful defense of any
  action, suit or proceeding) is asserted by such director, officer, or
  controlling person in connection with the securities being registered, the
  registrant will, unless in the opinion of its counsel the matter has been
  settled by controlling precedent, submit to a court of appropriate jurisdiction
  the question whether such indemnification by it is against public policy as
  expressed in the Securities Act of 1933 and will be governed by the final
  jurisdiction of such issue.
  
                                         4
  5
  
                                     SIGNATURES
  
  Pursuant to the requirements of the Securities Act of 1933, the Registrant
  certifies that it has duly caused this Registration Statement to be signed on
  its behalf by the undersigned, thereunto duly authorized, in the Town of Woburn,
  Commonwealth of Massachusetts, as of June 29, 2000.
  
                                          ANTIGENICS INC.
  
                                          By: /s/ Garo H. Armen, Ph.D.
                                             ----------------------------------
                                             Garo H. Armen, Ph.D.
                                             Chief Executive Officer and
                                             Chairman of the Board of Directors
  
                                  POWER OF ATTORNEY
  
  We, the undersigned officers and directors of Antigenics Inc., hereby severally
  constitute and appoint Garo H. Armen, Ph.D., Edward Brodsky and Michael Lytton
  and each of them singly, our true and lawful attorneys-in-fact, with full power
  to them in any and all capacities, to sign any and all amendments to this
  Registration Statement on Form S-8 (including any post-effective amendments
  thereto), and to file the same, with exhibits thereto and other documents in
  connection therewith, with the Securities and Exchange Commission, hereby
  ratifying and confirming all that each of said attorneys-in-fact may do or cause
  to be done by virtue hereof.
  
  Pursuant to the requirements of the Securities Act of 1933, this Registration
  Statement has been signed below by the following persons in the capacities and
  as of the dates indicated.
  SIGNATURE                                              TITLE                                DATE
  /s/  Garo H. Armen, Ph.D.                            Chief Executive Officer and          June 29, 2000
  -------------------------------------                  Chairman of the Board of
  Garo H. Armen, Ph.D.                                   Directors (Principal Executive
                                                         Officer and Principal Financial
                                                         and Accounting Officer)
  
    /s/  Pramod Srivastava, Ph.D.                        Director                             June 29, 2000
  -------------------------------------
  Pramod Srivastava, Ph.D.
  
    /s/  Noubar Afeyan, Ph.D.                            Director                             June 29, 2000
  -------------------------------------
  Noubar Afeyan, Ph.D.
  
    /s/  Edward Brodsky                                  Director                             June 29, 2000
  -------------------------------------
  Edward Brodsky
  
    /s/  Gamil de Chadarevian                            Director                             June 29, 2000
  -------------------------------------
  Gamil de Chadarevian
  
                                                         Director
  -------------------------------------
  Tom Dechaene
  
    /s/  Donald Panoz                                    Director                             June 29, 2000
  -------------------------------------
  Donald Panoz
  
    /s/  Martin Taylor                                   Director                             June 29, 2000
  -------------------------------------
  Martin Taylor
  5
  6
  
                                    EXHIBIT INDEX
  
         EXHIBIT
          NUMBER        DESCRIPTION
  
           4.1      Certificate of Incorporation of Antigenics Inc. Filed as
                    Exhibit 3.1 to our Registration Statement on Form S-1 (File
                    No. 333-91747) and incorporated herein by reference.
  
           4.2      By-laws of Antigenics Inc. Filed as Exhibit 3.2 to our
                    Registration Statement on Form S-1 (File No. 333-91747) and
                    incorporated herein by reference.
  
           4.3      Form of Warrant to purchase Common Stock, together with a list
                    of holders. Filed as Exhibit 4.1 to our Registration Statement
                    on Form S-1 (File No. 333-91747) and incorporated herein by
                    reference.
  
           4.4      Form of Subscription Agreement, as amended, together with a
                    list of parties thereto. Filed as Exhibit 4.2 to our
                    Registration Statement on Form S-1 (File No. 333-91747) and
                    incorporated herein by reference.
  
           5.1      Opinion of Palmer & Dodge LLP. Filed herewith.
  
          23.1      Consent of KPMG LLP. Filed herewith.
  
          23.2      Consent of Palmer & Dodge LLP. Included in the opinion filed
                    as Exhibit 5.1.
  
          24.1      Power of Attorney. Included on the signature page hereto.
  
          99.1      1999 Equity Incentive Plan. Filed as Appendix A to our Proxy
                    Statement on Schedule 14A filed on April 24, 2000 (File No.
                    000-29089) and incorporated herein by reference.