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                       SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549
                  --------------------------------------------

                        SCHEDULE 13D/A1 (Amendment No. 1)
                    Under the Securities Exchange Act of 1934

                                  Nanogen, Inc.
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                                (Name of Issuer)

                    Common Stock, par value $0.001 per share
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                         (Title of Class of Securities)

                                   630075 10 9
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                                 (CUSIP Number)

                        Elan International Services, Ltd.
                               102 St. James Court
                              Flatts, Smiths FL 04
                                     Bermuda
                                 (441) 292-9169


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   (Name, Address and Telephone Number of Person Authorized to Receive Notices
                              and Communications)


                                  June 29, 2000
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             (Date of Event which Requires Filing of this Statement)


If the filing person has previously filed a statement on Schedule 13G to report
the acquisition that is the subject of this Schedule 13D, and is filing this
schedule because of ss.ss. 240.13d-1(e), 240.13d-1(f) or 240.13d-1(g), check the
following box [ ].

NOTE: Schedules filed in paper format shall include a signed original and five
copies of the schedule, including all exhibits. See Rule 240.13d-7 for other
parties to whom copies are to be sent.

*The remainder of this cover page shall be filled out for a reporting person's
initial filing on this form with respect to the subject class of securities, and
for any subsequent amendment containing information which would alter
disclosures provided in a prior cover page.

The information required on the remainder of this cover page shall not be deemed
to be "filed" for the purpose of Section 18 of the Securities Exchange Act of
1934 ("Act") or otherwise subject to the liabilities of that section of the Act
but shall be subject to all other provisions of the Act (however, see the
Notes).


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CUSIP No. 630075 10 9
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      (1) NAME OF REPORTING PERSONS
                  --------------------------------------------------------------
                  Elan International Services, Ltd.
                  I.R.S. IDENTIFICATION NOS. OF ABOVE PERSONS (entities only)
                  N/A

----------------- --------------------------------------------------------------
      (2)         CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP (See
                  Instructions) (a) [ ]
                                (b) [ ]

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      (3) SEC USE ONLY


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      (4)         SOURCE OF FUNDS (See Instructions)
                  WC

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      (5)         CHECK IF DISCLOSURE OF LEGAL PROCEEDINGS IS REQUIRED PURSUANT
                  TO ITEMS 2(d) or 2(e)  [  ]

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      (6) CITIZENSHIP OR PLACE OF ORGANIZATION
                  Bermuda
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   Number of      (7)    SOLE VOTING POWER
     Shares              0

                  --------------------------------------------------------------
  Beneficially    (8)    SHARED VOTING POWER
     Owned               0

                  --------------------------------------------------------------
    by Each       (9)    SOLE DISPOSITIVE POWER
   Reporting             0

                  --------------------------------------------------------------
  Person With     (10)   SHARED DISPOSITIVE POWER
                         0

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      (11) AGGREGATE AMOUNT BENEFICIALLY OWNED BY EACH REPORTING PERSON
                  0

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      (12)        CHECK IF THE AGGREGATE AMOUNT IN ROW (11) EXCLUDES CERTAIN
                  SHARES (See Instructions)  [  ]

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      (13)        PERCENT OF CLASS REPRESENTED BY AMOUNT IN ROW (11)
                  0
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      (14)        TYPE OF REPORTING PERSON (See Instructions) CO
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Item 1.  Security and Issuer.

     Item 1 of Schedule 13D is hereby amended and restated in its entirety as
follows:

     This Amendment No. 1 amends Schedule 13D filed with the Securities and
Exchange Commission on August 17, 1998 by Elan International Services, Ltd.
("EIS"), a Bermuda exempted company, with respect to the common stock, $0.01 par
value per share (the "Common Stock"), of Nanogen, Inc., a Delaware corporation
whose principal offices are located at 10398 Pacific Center Court, San Diego, CA
92121.

Item 2.  Identity and Background.

     Item 2 of Schedule 13D is hereby amended and restated in its entirety as
follows:

     This Schedule 13D is filed by EIS, a wholly-owned subsidiary of Elan
Corporation, plc, an Irish public limited company ("Elan"). EIS's principal
place of business is 102 St. James Court, Flatts, Smiths, FL 04 Bermuda. EIS is
an investment holding company. Elan's principal place of business is Lincoln
House, Lincoln Place, Dublin 2, Ireland. Elan is a worldwide biopharmaceutical
company.

     Schedule A to this Schedule 13D sets forth the (a) name, (b) residence or
business address, (c) present principal occupation or employment and the name,
principal business and address of any corporation or other organization in which
such employment is conducted and (d) citizenship or place of organization of
each executive officer, director and controlling person of EIS and Elan.

     During the last five years, neither EIS, Elan nor any person identified on
Schedule A to this Schedule 13D: (i) has been convicted in a criminal proceeding
(excluding traffic violations or similar misdemeanors); or (ii) was a party to a
civil proceeding of a judicial or administrative body of competent jurisdiction,
as a result of which proceeding it was or is subject to a judgment, decree or
final order enjoining future violations of, or prohibiting or mandating
activities subject to, United States federal or state securities laws, or
finding any violation with respect to such laws.

Item 5.  Interest in Securities of Issuer.

     Item 5 of Schedule 13D is hereby amended and restated as follows:

               (a)  None.

               (b)  None.

               (c)  N/A

               (d)  N/A

               (e)  EIS ceased to be the beneficial owner of more than five
                    percent of the Common Stock on June 29, 2000.

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SIGNATURE

     After reasonable inquiry and to the best of its knowledge and belief, the
undersigned certifies that the information set forth in this statement is true,
complete and correct.

Dated:   February  17, 2004



                               ELAN INTERNATIONAL SERVICES, LTD.



                               By:  /s/ Kevin Insley
                                    --------------------------------------------
                               Name:     Kevin Insley
                               Title:    President & Chief Financial Officer




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                                   SCHEDULE A

The (a) name, (b) business address, (c) present principal occupation or
employment and the name, principal business and address of any corporation or
other organization in which such employment is conducted and (d) citizenship of
each executive officer and director (other than Messrs. Armen, Boushel, Crowley,
Gillespie, Groom, McGowan, McIntyre, McLaughlin, Selkoe, Thornburgh and Tully
and Ms. Gray) of Elan are set forth below:

1.   (a) G. Kelly Martin, (b) 345 Park Avenue, New York, New York 10154, (c)
     President and Chief Executive Officer, and (d) United States.

2.   (a) Shane Cooke, (b) Lincoln House, Lincoln Place, Dublin 2, Ireland, (c)
     Executive Vice President and Chief Financial Officer, and (d) Ireland.

3.   (a) William F. Daniel (b) Lincoln House, Lincoln Place, Dublin 2, Ireland,
     (c) Executive Vice President and Company Secretary, and (d) Ireland.

4.   (a) Jean Duvall, (b) 800 Gateway Blvd., South San Francisco, CA 94080, (c)
     Executive Vice President and General Counsel, and (d) United States.

The (a) name, (b) business address, (c) present principal occupation or
employment and the name, principal business and address of any corporation or
other organization in which such employment is conducted and (d) citizenship of
each director (other than Messrs. Martin and Daniel) of Elan are set forth
below:

1.   (a) Garo A. Armen, Ph.D., (b) 630 Fifth Avenue, Suite 2167, New York, New
     York 10111, (c) Chairman of the Board and Chief Executive Officer of
     Antigenics, Inc., and (d) United States.

2.   (a) Brendan E. Boushel, (b) 9 Upper Mount Street, Dublin 2, Ireland, (c)
     Retired, and (d) Ireland.

3.   (a) Laurence G. Crowley, (b) c/o Elan Corporation, plc, Lincoln House,
     Lincoln Place, Dublin 2, Ireland, (c) Governor (Chairman) Bank of Ireland,
     and (d) Ireland.

4.   (a) Alan R. Gillespie, Ph.D., (b) c/o Elan Corporation, plc, Lincoln House,
     Lincoln Place, Dublin 2, Ireland, (c) Chairman, Ulster Bank Limited, and
     (d) United Kingdom.

5.   (a) Ann Maynard Gray, (b) c/o Elan Corporation, plc, Lincoln House, Lincoln
     Place, Dublin 2, Ireland, (c) Retired, and (d) United Kingdom.

6.   (a) John Groom, (b) c/o Elan Corporation, plc, Lincoln House, Lincoln
     Place, Dublin 2, Ireland, (c) Retired, and (d) United Kingdom.

7.   (a) Kieran McGowan, (b) c/o Elan Corporation, plc, Lincoln House, Lincoln
     Place Dublin 2, Ireland, (c) Retired, and (d) Ireland.

8.   (a) Kevin McIntyre, M.D., (b) c/o Elan Corporation, plc, Lincoln House,
     Lincoln Place, Dublin 2, Ireland, (c) Associate Clinical Professor of
     Medicine at Harvard Medical School, and (d) United States.

9.   (a) Kyran McLaughlin, (b) Davy House, 49 Dawson Street, Dublin 2, Ireland,
     (c) Head of Equities and Corporate Finance, Davy Stockbrokers, and (d)
     Ireland.

10.  (a) Dennis J. Selkoe, M.D., (b) c/o Elan Corporation, plc, Lincoln House,
     Lincoln Place, Dublin 2, Ire-


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     land, (c) Professor of Neurology and Neuroscience at Harvard Medical
     School, and (d) United States.

11.  (a) Richard L. Thornburgh, (b) c/o Elan Corporation, plc, Lincoln House,
     Lincoln Place, Dublin 2, Ireland, (c) Counsel to the law firm of
     Kirkpatrick & Lockhart LLP, and (d) United States.

12.  (a) Daniel P. Tully, (b) c/o Elan Corporation, plc, Lincoln House, Lincoln
     Place, Dublin 2, Ireland, (c) Retired, and (d) United States.

The (a) name, (b) business address, (c) present principal occupation or
employment and the name, principal business and address of any corporation or
other organization in which such employment is conducted and (d) citizenship of
each executive officer and director of EIS are set forth below:

1.   Kevin Insley, (b) c/o 102 St. James Court, Flatts, Smiths Bermuda, (c)
     Director, President and Chief Financial Officer, and (d) United Kingdom.

2.   (a) Debra Moore Buryj, (b) c/o 102 St. James Court, Flatts, Smiths,
     Bermuda, (c) Director and Vice President and, (d) United States.

3.   (a) David J. Doyle, (b) c/o Clarendon House, 2 Church Street, Hamilton HM
     11, Bermuda, (c) Director of EIS, and principal occupation is lawyer, law
     firm of Conyers, Dill & Pearman, Clarendon House, 2 Church Street, Hamilton
     HM 11, Bermuda, and (d) Bermuda.



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