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                                                                   Exhibit 4.5


EXECUTION COPY

                             DATE: 27TH JANUARY 2003

                             AMARIN CORPORATION PLC.
                                       AND
                        ELAN PHARMA INTERNATIONAL LIMITED

                                DEED OF VARIATION
                                   RELATING TO
                       OPTION AGREEMENT DATED 18 JUNE 2001
                                  (ZELAPAR(R))
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                                      INDEX

1.       DEFINITIONS AND INTERPRETATION...................................1


2.       INTRODUCTION.....................................................1


3.       VARIATIONS.......................................................1


4.       CONFIRMATION OF THE AGREEMENT....................................4


5.       EXECUTION AND DELIVERY...........................................4


6.       MISCELLANEOUS....................................................4
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THIS DEED OF VARIATION is made the 27th January 2003

BETWEEN:

(1)   AMARIN CORPORATION PLC, a company incorporated in England and Wales
      (registered no. 002353920), whose registered office is 7 Curzon
      Street, London, W1J 5HG England ("AMARIN"); and

(2)   ELAN PHARMA INTERNATIONAL LIMITED, a company incorporated in the Republic
      of Ireland, whose registered office is at WIL House, Shannon Business
      Park, Shannon, Co Clare, Ireland ("ELAN").

WHEREAS:

(A)   Amarin and Elan entered into an Option Agreement dated 18 June 2001
      (the "AGREEMENT").

(B)   Elan Corporation, plc., Elan, Elan International Services Limited, Elan
      Pharmaceuticals, Inc., Monksland Holdings BV and Amarin have entered into
      a Master Agreement of even date herewith (the "MASTER AGREEMENT").

(C)   Pursuant to the Master Agreement, Amarin and Elan have agreed to amend the
      Agreement by and upon the terms of this Deed.

NOW THIS DEED WITNESSES AS FOLLOWS:

1.    DEFINITIONS AND INTERPRETATION

1.1.  Unless the context otherwise requires, all other words and expressions
      defined in the Agreement shall have the same meaning in this Deed.

1.2.  Reference to clauses herein are to clauses in the Agreement.

2.    INTRODUCTION

This Deed is supplemental to the Agreement.

3.    VARIATIONS

The parties to this Deed agree that with effect from the date hereof the
Agreement shall be varied as follows:

3.1.  Section 3.1(d) shall be deleted in its entirety and replaced with
      the following:

      "(d) Among other things, the Assignment Agreement shall provide that
      Amarin shall assume and perform Elan's obligations under the Scherer
      Agreement as of the date of the transfer and assignment of the Rights;
      that in the event of a conflict between the Scherer Agreement and the
      Assignment Agreement, the Scherer Agreement shall control; that the
      parties shall cooperate reasonably to enable the other to fulfill their
      respective remaining obligations under the Scherer Agreement in and
      outside the Territory; and that in the event of a material breach by
      Amarin of the Assignment Agreement or of this Agreement (including
      without limitation failure to pay the sum referred to in Section
      7.1(a)(ii) or any milestone payment), or of any other agreement between
      Amarin and Elan or any Elan Affiliate, which is not remedied within 90
      (ninety) days of Elan giving written notice to Amarin of such breach, or
      in the event of the insolvency of Amarin, the Rights shall revert to
      Elan. For the purposes of this Agreement, "Elan Affiliate" means Elan
      Corporation, plc.


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      and each of its subsidiaries, within the meaning of Section 736 of the
      Companies Act 1985 (UK)."

3.2.  Section 3.2 shall be varied by the insertion of the words "the Approval
      Date, the "Approval Date" being" immediately after the words "... thirty
      (30) days from".

3.3.  Section 3.4 shall be varied by the insertion of the words "subject
      to Section 4.4" between the words "During the Option Period, Elan
      shall" and "be responsible for and...".

3.4.  Section 4.4 shall be deleted in its entirety and replaced with the
      following:

      "4.4 Expenses. The costs and expenses associated with the parties'
      respective performance of their obligations under this Agreement shall be
      borne as follows:

      (a)   Elan will bear all costs and expenses (internal and external)
            incurred prior to 31 December 2002 (the "AMENDMENT DATE") and
            associated with performing its obligations under this Agreement,
            including without limitation Section 3.4 above, and the
            implementation of the Plan prior to the Amendment Date.

      (b)   Subject to Section 4.5, Amarin shall be responsible for all
            reasonable and verifiable Out Of Pocket Costs, whether
            incurred by Elan, Amarin or a third party where such Out Of
            Pocket Costs have been approved previously by the Steering
            Committee and such Out Of Pocket Costs are not attributable to
            a negligent act or omission or breach of the terms of this
            Agreement or the Assignment Agreement by, or on behalf of,
            Elan.

      (c)   Each party shall be responsible for its costs and expenses which are
            not Out Of Pocket Costs in connection with (i) Elan's activities
            pursuant to Section 3.4 and/or (ii) the implementation of the Plan,
            incurred on or after the Amendment Date.

      For the purposes of this Section 4.4, "OUT OF POCKET COSTS" shall mean
      all amounts payable to third parties, including without limitation
      contractors, incurred on or after the Amendment Date in connection with
      (i) Elan's activities pursuant to Section 3.4 and/or (ii) the
      implementation of the Plan."

3.5.  After Section 4.4 there shall be added the following new Sections
      4.5 and 4.6:

      "4.5 Process and Audit.

            (a)   Within 15 days of the end of each calendar month following the
                  Amendment Date, Elan and Amarin shall provide to each other a
                  statement of their Out Of Pocket Costs incurred in the
                  previous calendar month. Within 15 days thereafter, Amarin
                  shall pay to Elan an amount equivalent to such Out Of Pocket
                  Expenses of Elan.

            (b)   For the 90 day period following the close of each calendar
                  year, Amarin and Elan will, in the event that the other party
                  reasonably requests such access, provide each other's
                  independent certified accountants (reasonably acceptable
                  to the other party) with access, during regular business
                  hours and subject to the confidentiality provisions as
                  contained in this Agreement, to such party's books and
                  records relating to Out Of Pocket Costs, solely for the
                  purpose of verifying the accuracy and reasonable
                  composition of the calculations hereunder for the
                  calendar year then ended.


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            (c)   In the event of a discovery of a discrepancy which exceeds
                  five per cent (5%) of the amount due or charged by a party for
                  any period, the cost of such audit shall be borne by the
                  audited party; otherwise, such cost shall be borne by the
                  auditing party.

      4.6 Credit. Amarin shall be entitled to recover one half of Amarin's and
      Elan's Out Of Pocket Costs previously approved by the Steering Committee
      as a credit against the amount payable under Section 7.2(a), up to a
      maximum credit of Five Million Dollars ($5,000,000). For the avoidance of
      doubt, in the event that Amarin does not exercise the Option, or the
      amount under Section 7.2(a) otherwise does not become payable for any
      reason, Amarin shall not be entitled to any refund or contribution in
      respect of Out Of Pocket Costs of Amarin or Elan."

3.6.  Section 7.1 shall be deleted in its entirety and replaced with the
       following:

      "7.1  Purchase Price.  Amarin shall pay to Elan:

      (a)    if (x) the Approval Date is prior to 30 September 2003 and (y)
             Amarin is not in default of its payment obligations under the
             Loan Agreement dated 28 September 2001 (as amended) with Elan
             or the Amended and Restated Distribution, Marketing and
             Option Agreement dated 28 September 2001 (as amended) (which
             agreement concerns the product Permax) by and between Elan
             Pharmaceuticals, Inc. and Amarin, other than a clerical or
             administrative error in respect of the calculation of
             interest under the Loan Agreement, written notice of which
             default has been given by Elan, or as the case may be by the
             Elan Affiliate, to Amarin and (z) Amarin so elects by written
             notice to Elan at the time of exercise of the Option, the
             following non-refundable amounts:

             (i)    Two Million Two Hundred and Fifty Thousand Dollars
                    ($2,250,000) upon closing of the Option, which shall occur
                    on a mutually agreed date as soon as practicable after the
                    exercise of the Option; and

             (ii)   Eight Million Dollars ($8,000,000) ninety (90) days from the
                    Approval Date, but in no event later than the later of (x)
                    exercise of the Option and (y) 30 September 2003;

      (b)    in all other cases, the non-refundable amount of Ten Million
             Dollars ($10,000,000) upon closing of the Option.

      Such payment or payments shall not be subject to any future performance
      obligations of Elan to Amarin and shall not be applicable against any
      future services provided by Elan to Amarin."

3.7.  Section 7.2(a) shall be varied by the deletion of the words "Twelve
      Million Five Hundred Thousand Dollars ($12,500,000)" and the substitution
      therefor of the words "Seventeen Million Five Hundred Thousand Dollars
      ($17,500,000)".

3.8.  After Section 8.3 there shall be added the following new Section 8.4:

      "8.4 Elan may terminate this Agreement and the Option in the event
      that:

      (a)   Amarin materially breaches any agreement (other than this Agreement)
            between Amarin and Elan or any Elan Affiliate, which breach is not
            remedied within 90 (ninety) days of Elan giving written notice to
            Amarin of such breach;


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      (b)   Amarin is unable to pay its debts as they fall due, commences
            negotiations with any one or more of its creditors (other than Elan
            and/or Elan Affiliates) with a view to the general readjustment or
            rescheduling of its indebtedness or makes a general assignment for
            the benefit of or composition with its creditors;

      (c)   Amarin takes any corporate action or other steps are taken or legal
            proceedings are started for its winding up (which are not
            dismissed or struck out within seven days of presentation), or
            for its dissolution, administration or re-organisation (other
            than in connection with a bona fide solvent restructuring) or
            for the appointment of a liquidator, receiver, administrator,
            administrative receiver, trustee or similar officer of it or
            of all or a substantial part of its revenues and assets; or

      (d)   any execution or distress is levied against, or an encumbrancer
            takes possession of, the whole or any substantial part of, the
            property, undertakings or assets of Amarin or any event occurs which
            under the laws of any jurisdiction has a similar or analogous
            effect."

3.9.  Section 9 shall be varied by the addition of the words "and the
      Option" between the words "...immediately terminate this Agreement"
      and "by written notice...".

3.10. Section 10.3 shall be varied by the addition of the words ", Section 8.4
      and Section 9" after the words "Section 8.3".

4.    CONFIRMATION OF THE AGREEMENT

Save as varied by this Deed, the parties hereto confirm that the Agreement shall
continue in full force and effect in all respects.

5.    EXECUTION AND DELIVERY

5.1.  Each of the parties to this document intends it to be a Deed and agrees
      that upon it being dated it shall be treated as having been delivered as
      a Deed.

5.2.  The signing of this Deed by or on behalf of the parties hereto shall
      constitute an authority to their respective solicitors (or any of them)
      or any agent or an employee of them to date it as a Deed on behalf of the
      parties.

6.    MISCELLANEOUS

6.1.  The provisions of Article 10 (Miscellaneous) of the Agreement shall be
      incorporated into this Deed mutatis mutandis.

IN WITNESS whereof the parties have executed and delivered this Deed the date
first above written.


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EXECUTED as a DEED by         )
AMARIN CORPORATION PLC        )
acting by:-                   )

Director          /s/ Richard Stewart

Secretary         /s/ Jonathan Lamb

SIGNED and delivered as a Deed    )
by                                ) /s/ Kevin Insley
as attorney for                   )
ELAN PHARMA INTERNATIONAL         )
LIMITED                           )
in the presence of:               )


------------------------
Signature of witness


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