EXHIBIT 10.252


                             Dated November 12, 2002



                       LIGAND PHARMACEUTICALS INCORPORATED

                        ELAN INTERNATIONAL SERVICES, LTD.

                                       AND

                              ELAN CORPORATION PLC





                     AMENDMENT NO. 1 TO AMENDED AND RESTATED
                          REGISTRATION RIGHTS AGREEMENT







                     AMENDMENT NO. 1 TO AMENDED AND RESTATED
                          REGISTRATION RIGHTS AGREEMENT


     THIS AMENDMENT NO. 1 TO AMENDED AND RESTATED REGISTRATION RIGHTS AGREEMENT
(this "Amendment") is made on the 12th day of November, 2002, by and between
Ligand Pharmaceuticals Incorporated, a Delaware corporation (the "Company"),
Elan Corporation plc, a public limited company organized under the laws of the
Republic of Ireland ("Elan"), and Elan International Services, Ltd., a Bermuda
exempted Company ("EIS").

                                    RECITALS

     WHEREAS, concurrently with the execution of this Amendment, the Company,
Elan and EIS are entering into a Securities Purchase Agreement and the Company
and Elan are entering into an Amended and Restated Licence and Supply Agreement;

     WHEREAS, the Company, Elan and EIS and certain other holders of the
Company's capital stock have previously entered into that certain Amended and
Restated Registration Rights Agreement dated June 29, 2000, including the
addenda entered into through the date hereof (the "Prior Agreement");

     WHEREAS, Section 2.6(b) of the Prior Agreement provides that the Prior
Agreement may be amended with the written consent of the holders of a majority
of the Registrable Securities (as such term is defined in the Prior Agreement)
then outstanding; and

     WHEREAS, the Company, Elan and EIS desire to amend certain terms of the
Prior Agreement as set forth in this Amendment.

     THE PARTIES HEREBY AGREE AS FOLLOWS:

     1. SECTION 1.1(F). Section 1.1, paragraph (f) of the Prior Agreement is
hereby restated in its entirety as follows:

     "(f) The term "Registrable Securities" means (i) the shares of Common Stock
(or the shares of such other class of stock into which the Common Stock is
converted) issuable upon conversion of those certain Unsecured Convertible
Promissory Notes dated October 30, 1997 issued to S.R. One Limited (the "S.R.
One Notes") pursuant to the Stock and Note Purchase Agreement dated February 3,
1995 (and upon such conversion of the S.R. One Notes, SCHEDULE A shall be
updated to include such shares), (ii) the shares of Common Stock (or the shares
of such other class of stock into which the Common Stock is converted) issuable
upon conversion of that certain Warrant (the "SmithKline Warrant") issued to
SmithKline Beecham plc pursuant to the Stock Purchase Agreement dated April 24,
1998 (and upon such conversion of the SmithKline Warrant, SCHEDULE A shall be
updated to include such shares), (iii) the 1,278,970 shares of Common Stock (or
that number of shares of such other class of stock into which the Common Stock
is converted) issued to EIS pursuant to the Stock Purchase Agreement dated
September 30, 1998, (iv) the 437,768 shares of Common Stock (or that number of
shares of such other class of stock into which the Common Stock is converted)
issued to EIS pursuant to the Securities Purchase Agreement dated November 6,
1998 (as amended, the "Elan Securities Purchase Agreement"), (v) the shares of
Common Stock (or that number of shares of such other class of stock into which
the Common Stock is converted) issued to EIS upon conversion of the

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Zero Coupon Convertible Senior Notes due 2008 issued pursuant to the Elan
Securities Purchase Agreement, (vi) the shares of Common Stock (or that number
of shares of such other class of stock into which the Common Stock is converted)
issued to Elan or EIS pursuant to the Development, Licence and Supply Agreement
dated November 9, 1998, as amended and restated, (vii) the 52,742 shares of
Common Stock (or that number of shares of such other class of stock into which
the Common Stock is converted) issued to EIS pursuant to the Stock Purchase
Agreement dated September 30, 1999, (viii) the 91,406 shares of Common Stock (or
that number of shares of such other class of stock into which the Common Stock
is converted) issued to EIS upon the exercise of that certain Amended and
Restated Series X Warrant for the Purchase of 91,406 Shares of Common Stock
dated November 22, 1999, (ix) the 188,572 shares of Common Stock (or that number
of shares of such other class of stock into which the Common Stock is converted)
issued to EIS pursuant to the Incentive Agreement dated December 31, 1999, (x)
the 98,580 shares of Common Stock (or that number of shares of such other class
of stock into which the Common Stock is converted) issued to EIS pursuant to the
Incentive Agreement dated March 1, 2000, (xi) the 274,843 shares of Common Stock
(or that number of shares of such other class of stock into which the Common
Stock is converted) issued to EIS pursuant to the Incentive Agreement dated
December 20, 2001, (xii) the 102,151 shares of Common Stock (or that number of
shares of such other class of stock into which the Common Stock is converted)
issued to EIS pursuant to the Incentive Agreement dated March 28, 2002, and
(xiii) any Common Stock issued as (or issuable upon the conversion or exercise
of any warrant, right or other security which is issued as) a dividend or other
distribution with respect to, or in exchange for or in replacement of the shares
referenced in subsections (i) through (xii) above, excluding in all cases,
however, any Registrable Securities sold by a person in a transaction in which
rights under this Agreement are not assigned."

     2. SECTION 1.2(D). There shall be added to the Prior Agreement a new
Section 1.2(d) which shall read in its entirety as follows:

     3. "(d) In addition to the rights and obligations set forth in this Section
1.2, if any Holder holding in the aggregate at least 4,000,000 shares of
Registrable Securities making a request pursuant to this Section 1.2
additionally requests that such registration statement on Form S-3 be effected
for an offering to be made on a delayed or continuous basis pursuant to Rule 415
under the Act covering all Registrable Securities owned by such Holder (a "Shelf
Registration Statement"), the Company shall include such information in the
written notice referred to in subsection 1.2(a). Additionally, at any time
during the effectiveness of any such Shelf Registration Statement, if any Holder
intends to distribute at least 3,000,000 shares of Registrable Securities
covered by such Shelf Registration Statement by means of an underwriting, such
Holder (a "Requesting Holder") may so advise the Company, and the Company shall
provide written notice of such Requesting Holder's intention to all other
Holders having Registrable Securities covered by such Shelf Registration
Statement (the "Covered Holders"). The underwriter for any underwritten offering
effected pursuant to this subsection 1.2(d) shall at the option of the Company
(i) be selected by the Company from the list attached hereto as EXHIBIT A hereto
and shall be reasonably acceptable to the Requesting Holder or (ii) be selected
by the Requesting Holder and shall be reasonably acceptable to the Company. The
right of any Covered Holder to include its Registrable Securities in such
underwritten offering shall be conditioned upon such Covered Holder's
participation in such underwriting and the inclusion of such Covered Holder's
Registrable Securities in the underwriting (unless otherwise mutually

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agreed by the Requesting Holder and such Holder) to the extent provided herein.
All Covered Holders proposing to distribute their securities through such
underwriting shall (together with the Company as provided in subsection 1.5(e))
enter into an underwriting agreement in customary form with the underwriter or
underwriters selected for such underwriting. Notwithstanding any other provision
of this Agreement, if the underwriter advises the Requesting Holder or the
Company in writing that marketing factors require a limitation of the number of
shares to be underwritten, then the Requesting Holder or the Company shall so
advise all Covered Holders of Registrable Securities which would otherwise be
underwritten pursuant hereto, and the number of shares of Registrable Securities
that may be included in the underwriting shall be allocated first to the
Requesting Holder, and second to the Covered Holders participating in the
underwritten offering in proportion (as nearly as practicable) to the amount of
Registrable Securities of the Company owned by each such Covered Holder;
PROVIDED, HOWEVER, that the number of shares of Registrable Securities to be
included in such underwriting shall not be reduced unless all other securities
which the Company proposes to sell are first entirely excluded from the
underwriting. The Company is obligated to effect only two (2) underwritten
offerings pursuant to this subsection 1.2(d) during the term of this Agreement;
PROVIDED, HOWEVER, that if the number of shares of Registrable Securities of the
Requesting Holder to be included in such underwritten offering is reduced by the
underwriter or underwriters selected for such underwriting below 3,000,000
shares, the underwritten offering initiated by such Requesting Holder shall not
be counted as an underwritten offering pursuant to this Section 1.2(d). For the
avoidance of doubt, the expenses of the two (2) underwritten offerings
contemplated by this Section 1.2(d) shall be treated for purposes of Section
1.2(c) in the same manner as the expenses of the filing of the Shelf
Registration Statement to which such underwritten offerings relate are treated.
Notwithstanding the foregoing, the Company shall not be obligated to effect any
underwritten offering pursuant to this subsection 1.2(d) if the Company shall
furnish to the Requesting Holder a certificate signed by the president of the
Company stating that in the good faith judgment of the Board of Directors of the
Company it would be materially detrimental to the Company and its stockholders
for such underwritten offering to be effected at such time (without taking into
account the costs to the Company), in which event the Company shall have the
right to defer the commencement of such underwritten offering for a period of
not more than 60 days after receipt of the request of the Requesting Holder
under this subsection 1.2(d); provided, however, that the Company shall not
utilize this right more than once in any twelve (12) month period."

     4. SECTION 1.2(E). There shall be added to the Prior Agreement a new
Section 1.2(e) which shall read in its entirety as follows:

     "(e) In each underwritten offering effected pursuant to subsection 1.2(d),
the Company shall use commercially reasonable efforts to (i) cause its senior
management to assist in customary selling efforts relating to the Registrable
Securities included in such underwritten offering as reasonably requested by the
managing underwriter, including participating in one usual and customary
"roadshow" in connection with such offering; provided, however, that any such
"roadshow" shall be limited to five (5) business days in duration; and (ii) make
reasonably available for inspection by the Holders including Registrable
Securities in such offering, one (1) single counsel for such Holders and the
underwriters for such offering and their counsel, at the offices where normally
kept, during reasonable business hours and upon reasonable notice to the
Company, all financial and other records and documents of the Company and its
subsidiaries that

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are pertinent to the offering, and cause the officers, directors, agents and
employees of the Company and its subsidiaries to supply all information that is
pertinent to such offering as is reasonably requested by such persons or
entities."

     5. SECTION 1.5(A). Section 1.5(a) of the Prior Agreement is hereby restated
in its entirety as follows:

"(a) Prepare and file with the SEC a registration statement with respect to such
Registrable Securities and use its best efforts to cause such registration
statement to become effective, and, upon the request of the Holders of a
majority of the Registrable Securities then outstanding, keep such registration
statement effective for up to one hundred twenty (120) days for a filing under
Section 1.3 or 1.4, and up to one hundred eighty (180) days for a filing under
Section 1.2; provided, however, that, notwithstanding the foregoing, the Company
shall keep any Shelf Registration Statement effective until the earlier of (i)
two (2) years from the date of effectiveness of such Shelf Registration
Statement and (ii) the date on which all Registrable Securities covered by such
Shelf Registration Statement have been sold pursuant to such Shelf Registration
Statement."

     6. SCHEDULE A of the Prior Agreement is hereby restated in its entirety as
attached to this Addendum.

     7. There shall be added to the Prior Agreement a new Exhibit A which shall
read in its entirety as follows:

                                    EXHIBIT A

                           Credit Suisse First Boston
                                  Goldman Sachs
                                 Morgan Stanley
                              Salomon Smith Barney
                                   UBS Warburg

     8. EFFECT OF PRIOR AGREEMENT. Except as set forth herein, the Prior
Agreement shall remain in full force and effect.

     9. MISCELLANEOUS.

          9.1 SUCCESSORS AND ASSIGNS. The terms and conditions of this Amendment
shall inure to the benefit of and be binding upon the respective successors and
assigns of the parties. Nothing in this Amendment, express or implied, is
intended to confer upon any party, other than the parties hereto or their
respective successors and assigns, any rights, remedies, obligations or
liabilities under or by reason of this Amendment, except as expressly provided
in this Amendment.

          9.2 GOVERNING LAW. This Amendment shall be governed by and construed
under the laws of the State of California as applied to agreements among
California residents entered into and to be performed entirely within
California.

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          9.3 TITLES AND SUBTITLES. The titles and subtitles used in this
Amendment are used for convenience only and are not to be considered in
construing or interpreting this Amendment.

          9.4 COUNTERPARTS. This Amendment may be executed in two or more
counterparts, each of which shall be deemed an original, but all of which
together shall constitute one and the same instrument.



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         IN WITNESS WHEREOF, the parties have executed this Amendment as of the
date first above written.


                         LIGAND PHARMACEUTICALS INCORPORATED

                         By: /S/DAVID E. ROBINSON
                         -----------------------------------
                         Name: David E. Robinson
                         Title: President & CEO

                         Address:          12075 Science Center Drive
                                           San Diego, CA  92121



                        ELAN INTERNATIONAL SERVICES, LTD.

                         By: /S/KEVIN INSLEY
                         -----------------------------------
                         Name:
                         Title:

                         Address:



                         By: /S/KEVIN INSLEY
                         -----------------------------------
                         Name:
                         Title:

                         Address:



                       [SIGNATURE PAGE TO AMENDMENT NO. 1
                             TO AMENDED AND RESTATED
                         REGISTRATION RIGHTS AGREEMENT]





                                   SCHEDULE A

                                       to
                               Amendment No. 1 to
               Amended and Restated Registration Rights Agreement



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                                                 SHARES
NAME                                             ISSUED
- ----------------------------------------- ----------------------
                                       
Elan International Services, Ltd.         14,041,326
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