Document:

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                                                                       EX-10.38

                            THIRD AMENDMENT TO LEASE

         THIS THIRD AMENDMENT TO LEASE ("AMENDMENT") is made and entered into as
of OCTOBER 13, 2000, by and between W9/PC LIMITED PARTNERSHIP, a Delaware
limited partnership ("LANDLORD") and IDEC PHARMACEUTICALS CORPORATION, a
Delaware corporation ("TENANT").

                                R E C I T A L S:

         A.       WHEREAS, Professors Fund I, L.P., an Arizona limited
partnership, Managing Agent for All Spectrum Services, Inc., a California
corporation ("ORIGINAL LANDLORD"), and IDEC Pharmaceuticals Corporation, a
California corporation ("ORIGINAL TENANT") entered into that certain Agreement
dated as of August 13, 1996 (the "ORIGINAL LEASE"), whereby Original Landlord
leased to Tenant and Tenant leased from Original Landlord the entire building
located at 3030 Callan Road, San Diego, California. The Original Lease was
subsequently amended by that certain First Amendment to Lease dated as of
October 1, 1999 ("FIRST AMENDMENT") and by that certain Second Amendment to
Lease dated as of June 16, 2000 ("SECOND AMENDMENT"). Landlord is the
successor-in-interest to Original Landlord and Tenant is the
successor-in-interest to Original Tenant. The Original Lease, as amended by the
First Amendment and the Second Amendment may be collectively referred to herein
as the "LEASE."

         B.       WHEREAS, by this Amendment, Landlord and Tenant desire to
provide for Tenant's restriping of the parking area, and otherwise modify the
Lease as set forth herein; and

         C.       WHEREAS, unless otherwise defined herein, capitalized terms as
used herein shall have the same meanings as given thereto in the Lease.

         NOW, THEREFORE, in consideration of the foregoing recitals and the
mutual covenants contained herein, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the
parties hereto agree as follows:

                               A G R E E M E N T:

         1.       Premises. Pursuant to the Lease, Tenant currently leases from
Landlord the entire building located at 3030 Callan Road, San Diego and the
entire building located at 3020 Callan Road, San Diego, and Tenant has also been
granted the right to use the common areas surrounding the referenced buildings
(collectively, the "PROJECT"). The Project contains a parking area that is used
exclusively by Tenant.

         2.       Restriping Parking Area. Tenant has requested Landlord's
consent to the restriping of the parking area at the Project. Landlord has
consented to such restriping based upon the terms and conditions outlined in
this Amendment. All costs associated with such work shall be paid for by Tenant,
at Tenant's sole cost and expense, and Landlord shall have no liability
therefor. Tenant shall use a licensed and reputable contractor reasonably
approved by Landlord for the performance of such restriping work and shall
ensure that such work is performed in a good and workmanlike manner. Landlord
shall have the right to review and approve (provided such approval shall not be
unreasonably withheld or delayed) any plans or specifications for the restriping
work.

         3.       Compliance with Law. Tenant will perform all work in
connection with the restriping of the parking area in accordance, and following
completion of such work the parking area shall comply as it relates to the
restriping, with all applicable laws, ordinances and codes, including, but not
limited to, the Americans With Disabilities Act, zoning requirements and any
applicable minimum parking ratio requirements.

         4.       Restoration Upon Termination. In the event Tenant ceases to
lease the entire Project, or upon the expiration or earlier termination of the
Lease, Landlord may, upon giving Tenant notice on or before the later of (i) the
expiration or earlier termination of the Lease, or (ii)

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the effective date of Tenant's downsizing, as applicable, require that Tenant
restore the striping in the parking area to the condition in which it existed
prior to Tenant's work pursuant to this Amendment. Such restoration shall be
performed by Tenant at Tenant's sole cost and expense using a licensed, and
reputable contractor reasonably approved by Landlord, and shall be completed
within thirty (30) days after the expiration or earlier termination of this
Lease, or the effective date of Tenant's downsizing, as applicable.

         5.       No Further Modification. Except as set forth in this
Amendment, all of the terms and provisions of the Lease shall continue to apply
and shall remain unmodified and in full force and effect. Effective as of the
date hereof, all references to the "Lease" shall refer to the Lease as amended
by this Amendment.

         IN WITNESS WHEREOF, this Amendment has been executed as of the day and
year first above written.

"LANDLORD"                              W9/PC LIMITED PARTNERSHIP,
                                        a Delaware limited partnership

                                        By: W9/PC, Inc., a Delaware corporation,
                                            general partner

                                            By: /s/ Ronald Lack
                                                --------------------------------
                                                Name: Ronald Lack
                                                Title: Vice President

"TENANT"                                IDEC PHARMACEUTICALS CORPORATION,
                                        a Delaware corporation

                                        By: /s/ Phillip Schnieder
                                            ------------------------------------
                                            Name: Phillip Schnieder
                                            Title: VP & CFO

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                                                                       EX-10.39

                            FIRST AMENDMENT TO LEASE

         This Agreement is entered into as of November 9, 1992, by and between
TORREY SORRENTO INC., a California corporation (hereinafter called "Landlord"),
and IDEC PHARMACEUTICALS CORPORATION, a California corporation (hereinafter
called "Tenant"), with reference to the following facts:

         A.       Prior hereto Landlord and Tenant entered into that certain
Lease dated July 9, 1992, for the premises located at 11011 Torreyana Road, San
Diego, California (the "Lease").

         B.       Landlord and Tenant now desire to amend the Lease on the terms
set forth herein.

         C.       All capitalized terms not defined herein shall have the same
meaning as set forth in the Lease.

         NOW, THEREFORE, the parties hereto agree as follows:

                  1.       A new Section 2.1.10 is hereby added to the Lease as
follows:

                           "2.1.10  Landlord's Mortgagee: The term "Landlord's
                  Mortgagee" shall mean the beneficiaries from time to time of
                  the first deed of trust encumbering the Demised Premises dated
                  November 25, 1992, in favor of four construction industry
                  labor-management pension trust funds. The agent for said
                  beneficiaries is Seidler Realty Advisors, who shall act as the
                  agent for the Landlord's Mortgagee. The term "Landlord's
                  Mortgagee" also includes said agent. By written notice from
                  all of said beneficiaries to Landlord and Tenant, said agent
                  may be changed to another party, in which event said new agent
                  shall thereafter act for the Landlord's Mortgagee. The address
                  for notice to Landlord's Mortgagee is:

                                                Seidler Realty Advisors
                                                4275 Executive Square, Suite 325
                                                La Jolla, CA 92037
                                                Attn: Daniel J. Ryan"

                  2.       The Lease is hereby amended by adding thereto the
following new Section 2.1.11:

                           "2.1.11  Landlord's Lender: The term "Landlord's
                  Lender" shall include Landlord's Mortgagee and any other
                  lender at any time which is the beneficiary of a first deed of
                  trust encumbering the Demised Premises."

                  3.       The Lease is hereby amended by adding thereto the
following new Paragraph 3.4:

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                           "3.4     Landlord and Tenant acknowledge that
                  Landlord's Mortgagee is a group of four construction industry
                  labor-management pension trust funds, and that, pursuant to
                  the terms of the loan from Landlord's Mortgagee, union labor
                  is to be used for constructing or rebuilding the improvements
                  to be constructed on the Demised Premises pursuant to the
                  terms of Exhibit "B" attached hereto. Such construction shall
                  be subject to the terms of the Commitment Letter from
                  Landlord's Mortgagee to Landlord dated October 8, 1992. Such
                  obligation to use union labor shall expire upon the extension
                  of the Maturity Date of the loan from Landlord's Mortgagee as
                  set forth in paragraph 1 of the promissory note evidencing the
                  same which the parties anticipate will occur no later than
                  December 31, 1993. Landlord and Tenant acknowledge that
                  neither Landlord nor Landlord's Mortgagee shall be responsible
                  for any additional costs arising from such use of union
                  labor."

                  4.       The second sentence of Section 4.2 of the Lease is
hereby amended and restated as follows:

                  "The terms "substantially complete(d)" and "substantial
                  completion" shall mean the earlier of (i) issuance of a
                  temporary certificate of occupancy by the City of San Diego or
                  (ii) the date the Project Architect (as defined in Section 1.1
                  of the Work Letter) has certified that Landlord's Work is
                  substantially complete and that Tenant can physically occupy
                  the space, subject to the punch-list items as described in
                  Section 7.2 of the Work Letter, and the Demised Premises are
                  in clean and operating condition, subject to punch-list items
                  that may still need to be corrected and subject to items which
                  constitute Tenant's Work."

                  5.       Section 4.2.3 of the Lease is hereby amended by
adding at the end of the first line of such section the words "by Landlord's
contractor."

                  6.       Sections 4.1 and 4.2.3 of the Lease are hereby
amended by eliminating Landlord's and Tenant's termination rights and by adding
thereto the following Section 4.2.4:

                           "Any other provision of this Lease to the contrary
                  notwithstanding, but without limiting Landlord's liabilities
                  or responsibilities under the Lease in any way whatsoever,
                  Tenant shall, subject to Force Majeure Delays and
                  Landlord-Caused Delays, fully occupy the entire Demised
                  Premises, conduct business therefrom and commence paying the
                  entire Initial Base Rent on or before December 31, 1993.
                  Tenant shall cooperate with Landlord in taking all good faith
                  steps necessary to allow Landlord to timely complete
                  Landlord's Work as

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                  required by Landlord's Mortgagee. Without limiting the
                  foregoing, Tenant shall provide to Landlord, Tenant's Plans
                  for the Landlord's work in a timely manner to allow Landlord
                  to complete the pilot plant by December 31, 1993. Tenant shall
                  not take any action which shall cause Landlord to be in
                  default under the loan from Landlord's Mortgagee."

                  7.       Paragraph 5.2 of the Lease is hereby amended by
adding thereto at the end thereof the following provision:

                           "In addition to any other obligation of Tenant
                  hereunder, in the event that Tenant shall be the proximate
                  cause of a default by Landlord under the loan from Landlord's
                  Mortgagee and Landlord's Mortgagee shall require Landlord to
                  thereafter deposit monthly installments of real property taxes
                  and insurance premiums, Tenant shall timely make such deposits
                  with Lender."

                  8.       Section 4 of the Lease is hereby amended by adding
thereto the following new Section 4.6:

                           "Any provision of this Lease to the contrary
                  notwithstanding, Tenant shall commence paying Basic Annual
                  Rent in the amount of $120,000 per month commencing May 25,
                  1993. Tenant shall further commence paying the full payment of
                  Basic Annual Rent on the earlier of (a) the Term Commencement
                  Date, (b) sixty three (63) days from May 25, 1993, plus the
                  period of any Landlord-Caused Delays or Force Majeure Delays,
                  or (c) December 31, 1993."

                  9.       The second sentence of Section 5.3 is hereby amended
and restated in its entirety as follows:

                  "Basic Annual Rent and Additional Rent shall together be
                  denominated "Rent." Rent shall be paid to Landlord, without
                  abatement, deduction or offset, (excepting only for the
                  limited circumstances as specified in Section 16.1 for
                  Landlord's maintenance, in Section 20.6 for destruction of a
                  portion of the Demised Premises and/or in connection with the
                  terms upon which Tenant provides a $3,200,000.00 loan for a
                  portion of the financing for the project costs) in lawful
                  money of the United States of America at the office of
                  Landlord as set forth in Section 2.1.8 herein or to such other
                  person or at such other place as Landlord may from time to
                  time designate in writing. In the event the term of this Lease
                  commences or ends on a day other than the first day of a
                  calendar month, then the Rent for such fraction of a month
                  shall be prorated for such period on the basis of

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                  a thirty (30) day month and shall be paid at the then current
                  rate for such fractional month."

                  10.      Section 5.3 of the Lease is hereby amended by adding
at the end thereof the following provision:

                  "Tenant shall also be entitled to a credit against Basic
                  Annual Rent for the difference between (i) any Basic Annual
                  Rent or Additional Rent payable by Tenant with respect to the
                  Demised Premises for any period between the date Tenant is
                  required to pay the same pursuant to the terms of Section 4.6
                  of this Lease and the date Tenant would have been required to
                  pay the same pursuant to the other terms of this Lease
                  (exclusive of Section 4.6), and (ii) any proceeds received by
                  Tenant for reimbursement therefor from the loan from
                  Landlord's Mortgagee that would otherwise be payable to
                  Landlord from the balance of any contingency or interest
                  reserve line items and Landlord's share of any penalties
                  payable by the general contractor to Borrower pursuant to the
                  terms of the general contract for the construction to be
                  performed pursuant to the terms of this Lease, which such sums
                  shall be payable to Tenant to the extent necessary to satisfy
                  such obligations. Tenant shall be entitled to interest on any
                  Rent so incurred at the rate payable under the promissory note
                  given by Borrower to Tenant in the same manner as pertains to
                  Tenant's credit against Basic Annual Rent pursuant to Section
                  5.4 of this Lease. Tenant shall also be entitled to the rent
                  credit set forth in Paragraph 40.5 of this Lease, to the
                  extent applicable. Provided, however, any such monthly rent
                  credit shall be limited to the greater of (i) Forty Seven
                  Thousand Five Hundred Dollars ($47,500.00), or (ii) the
                  difference between (a) the monthly installment of Basic Annual
                  Rent payable by Tenant and (b) the monthly debt service
                  payment which Landlord is obligated to pay on the loan from
                  Landlord's Mortgagee, with any uncredited portions continuing
                  to accrue with interest as otherwise provided in this Lease.
                  Notwithstanding the foregoing, during any period during which
                  Landlord's Mortgagee continues to have a first deed of trust
                  or is the owner through a foreclosure or deed in lieu thereof,
                  then in no event shall the amount of any rent credit cause the
                  monthly installment of Basic Annual Rent to be less than One
                  Hundred Forty Five Thousand Dollars ($145,500.00)."

                  11.      The third sentence of Section 5.4 of the Lease is
hereby amended by adding at the end thereof the phrase "but no later than ninety
(90) days after Tenant's quarterly and fiscal year end."

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                  12.      The next to last sentence of Section 5.4 is hereby
amended and restated in its entirety as follows:

                  "This Security Deposit shall be in cash; excepting, however,
                  Tenant shall have the option after the Term Commencement Date
                  to substitute an irrevocable bank letter of credit, in a form
                  and content and from a bank pre-approved in writing by
                  Landlord and Landlord's Mortgagee."

                  13.      Section 5.4 of the Lease is hereby amended by adding
at the end thereof the following provision:

                  "To the extent that Landlord's Lender forecloses under its
                  loan to Landlord or otherwise obtains title to the Demised
                  Premises and Tenant is not given credit for the Security
                  Deposit as a result thereof, Tenant shall be entitled to
                  credit against the Rent due for the last month of this Lease
                  the amount of such Security Deposit."

                  14.      Section 7.3 of the Lease is hereby amended by adding
a new sentence thereto after the first two sentences thereof, as follows:

                  "Upon the written request of Landlord, Tenant shall furnish to
                  Landlord written evidence that all such property taxes and
                  insurance premiums required in the first instance to be paid
                  by Tenant have been paid."

                  15.      Section 11.1 of the Lease is hereby amended by
revising the first line thereof to state as follows:

                  "If Tenant fails to fully vacate all or any part ...."

                  16.      Section 12.2 of the Lease is hereby amended by adding
at the beginning thereof the clause "Notwithstanding any provision of Section
7.2 to the contrary, ..."

                  17.      Section 15.5 of the Lease is hereby amended by
providing that a copy of the notice to be provided to the Landlord therein shall
also be provided to Landlord's Mortgagee.

                  18.      The last sentence of Section 16.2 of the Lease is
hereby amended and restated in its entirety as follows:

                  "Tenant shall, upon the expiration or sooner termination of
                  the term hereof, surrender the Demised Premises to Landlord in
                  the same good, quality condition as when received, ordinary
                  wear and tear excepted, and damage by fire, other peril or
                  condemnation which is to be repaired by Landlord pursuant to
                  Articles 20 and 21 also excepted."

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                  19.      The third to last line of Section 17.3 on Page 26 of
the Lease is hereby amended by adding after the word "clarify" the phrase "to
the reasonable satisfaction of such lender."

                  20.      Section 18.4 of the Lease is hereby amended by adding
in the first line thereof after the word "Landlord" the words "and Landlord's
Mortgagee."

                  21.      Section 19.1 of the Lease is hereby amended by adding
",automobile liability," in the seventh line on Page 28 of the Lease after the
words "materials risks."

                  22.      Section 19.3 of the Lease is hereby amended by adding
at the end of the first sentence thereof the phrase "and Landlord's Lender to
the extent that such lender has notified Tenant in writing of such request."

                  23.      Section 19.3 of the Lease is further amended by
providing that the policyholder rating set forth in the second sentence of such
section shall be "A-" and the financial category set forth in the second
sentence shall be "Class X."

                  24.      Section 19.5 of the Lease is hereby amended and
restated in its entirety as follows:

                           "19.5 If any policy of insurance is to name Landlord
                  or Landlord's Lender as additional insured, Tenant shall, upon
                  written request of Landlord or such lender, also designate and
                  furnish certificates evidencing Landlord and such lender as an
                  additional insured to (i) any lender to Landlord holding a
                  security interest in the Building or, and/or (ii) the Landlord
                  under any lease wherein Landlord is or shall become a tenant
                  under a ground lease for the Land rather than that of fee
                  owner, and/or (iii) Landlord's property manager, construction
                  manager, agents and representatives."

                  25.      Section 32.1 of the Lease is hereby amended by adding
thereto at the end thereof the phrase "or sue to compel specific performance
hereunder."

                  26.      Section 33.2 of the Lease is hereby amended and
restated in its entirety as follows:

                           "33.2 Notwithstanding the foregoing, Tenant shall
                  execute and deliver within thirty (30) says or such shorter
                  period as is reasonable under the circumstances after written
                  demand such further instrument or instruments evidencing such
                  subordination of this Lease to any such mortgages, deeds of
                  trust or leases in which Landlord is tenant as may be required
                  reasonably by Landlord's Lender. However, if any such
                  mortgagee,

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                  beneficiary or landlord under a lease wherein Landlord is
                  tenant so elects, this Lease shall be deemed prior to any such
                  lease, mortgage or deed of trust upon or including the Demised
                  Premises, regardless of date, and Tenant shall execute a
                  statement in writing to such effect at Landlord's request."

                  27.      Section 33.3 of the Lease is hereby amended by adding
at the end thereof the following sentence:

                  "Additionally, at the request of said purchaser or transferee,
                  Tenant and the purchaser or transferee shall sign a new lease
                  on the same terms and conditions set forth in this Lease
                  (except for as modified by any subordination agreement
                  hereafter executed if such subordination agreement so
                  requires) but showing the purchaser as the landlord."

                  28.      Section 34.2 of the Lease is hereby amended and
restated in its entirety as follows:

                           "34.2 The voluntary or other surrender of this Lease
                  by Tenant shall not work a merger, unless Landlord and
                  Landlord's Lender consent, and shall, at the option of
                  Landlord and Landlord's Lender, operate as an assignment to it
                  of any or all subleases or subtenancies."

                  29.      The Lease is hereby amended by adding thereto the
following new Section 34.4:

                           "34.4 In the event Tenant acquires fee ownership of
                  the Demised Premises, that acquisition will not result in a
                  merger of the leasehold interest and the fee interest, but
                  rather, at the option of Landlord's Lender, the Lease and the
                  Landlord's Lender's interests in the Lease shall remain in
                  effect. Landlord and Tenant shall execute such additional
                  documents as may be necessary to effectuate this waiver."

                  30.      Section 35.1 of the Lease is hereby amended by adding
thereto at the end of the first sentence thereof the words "and approved by
Landlord's Mortgagee."

                  31.      Section 37.1 of the Lease is hereby amended by adding
thereto in the tenth line thereof after the close of the parenthetical phrase
the following phrase:

                  "...excluding, however, any Hazardous Materials which were
                  placed on the Demised Premises by Tenant or Tenant's
                  Invitees...."

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                  32.      Section 37.1.2 of the Lease is hereby amended by
adding the following provision at the end thereof:

                  "Landlord may disclose such materials on a confidential basis
                  to Landlord's Mortgagee."

                  33.      Section 37.5.1 of the Lease is hereby amended by
adding after the word "Landlord" in the second line thereof the phrase "and
Landlord's Lender."

                  34.      Section 39.2.1 of the Lease is hereby amended by
revising the fifth line thereof on Page 58 to state as follows:

                  "...$10,000,000.00, which new loan proceeds are to cover a
                  portion of the Landlord's ...."

                  35.      The last two sentences in Section 39.2.1 of the Lease
are amended and restated as follows:

                  "The new loan shall enable Tenant to use the remaining loan
                  proceeds to complete the Landlord's Work in the event of a
                  material default by Landlord under the Work Letter if Tenant
                  is entitled to complete the same under the terms of this
                  Lease. Additionally if the new lender requires a completion
                  bond, Tenant shall be an additional beneficiary of the
                  completion bond."

                  36.      The Lease is hereby amended by adding thereto the
following Section 40:

                           "40.     Completion by Tenant.

                                    40.1.    Lender Requirement. Landlord's
                  Mortgagee under the construction/permanent financing for the
                  New Loan referenced in Section 39.2 above is allowing Tenant
                  to complete construction of the Landlord's Work to the
                  Demised Premises as permitted by Section 4.1.2 of Exhibit "B"
                  to this Lease in the event of the failure by Landlord to do
                  so. In recognition thereof, Landlord and Tenant have agreed to
                  the provisions set forth in this Section 40. The provisions
                  set forth below shall be applicable if, and only if, (i)
                  Landlord defaults on its obligations to complete construction
                  of the Landlord's Work, and (ii) Tenant exercises its right to
                  complete the Landlord's Work, and (iii) Tenant has not
                  materially defaulted on its obligations to provide the funds
                  to pay for the costs of the Landlord's Work, and (iv) there is
                  no other default by Tenant which is a proximate cause for
                  Landlord's failure to complete construction of the Landlord's
                  Work, in which event the provisions set forth below in this
                  Section 40 shall become applicable. Once these provisions
                  become

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                  applicable, these provisions shall prevail over any
                  inconsistent provisions contained elsewhere in this Lease
                  (including Exhibit B to this Lease).

                                    40.2.    Costs and Damages. Subject to the
                  provisions set forth below, notwithstanding anything to the
                  contrary in the Lease (including, without limitation, Sections
                  22.10, 18.3 and 18.4 thereof), Landlord shall indemnify Tenant
                  and its partners, directors, officers, agents and employees
                  against and save them harmless from all demands, claims,
                  damages, causes of action or judgments and all reasonable
                  expenses incurred in investigating or resisting the same
                  (including reasonable professional fees, including without
                  limitation, fees for attorneys, architects, engineers, and
                  environmental consultants and any costs or damages incurred
                  relative to a transition from Landlord to Tenant for
                  performing the Landlord's Work) arising from or out of
                  Tenant's performing the Landlord's Work. Tenant shall be
                  entitled to interest at the rate of Bank of America's
                  "reference rate" plus 3% on any amounts expended by Tenant as
                  provided herein.

                                    40.3.    Contractor's Delay Damages.
                  Pursuant to Section 6.3.7 of Exhibit B to this Lease (the Work
                  Letter), the delay damages payable by Landlord's Contractor
                  are to be shared between Landlord and Tenant. Landlord hereby
                  agrees that its share of said delay damages payable by
                  Landlord's Contractor shall initially be paid to Tenant, in
                  addition to Tenant's share to compensate Tenant for Tenant's
                  costs and damages under Section 40.2 above; provided, however,
                  to the extent that Landlord's share of said delay damages
                  exceeds Tenant's costs and damages as specified in Section
                  40.2 above, then Tenant shall pay over to Landlord the excess
                  portion of Landlord's share of said delay damages which exceed
                  Tenant's costs and damages pursuant to Section 40.2 above.

                                    40.4.    Delay Days. Any delays in
                  completing the Landlord's Work which result from Tenant taking
                  over from Landlord the responsibilities to perform Landlord's
                  Work shall be treated as Landlord-Caused Delays, pursuant to
                  Section 6.1 of Exhibit B (Work Letter), notwithstanding any
                  other contrary provisions. Notwithstanding the foregoing, the
                  time period within which Landlord must deliver the Demised
                  Premises to Tenant as set forth in Section 4.2.3 of the Lease
                  shall be extended by any such delay.

                                    40.5.    Rental Credit. To the extent that
                  Tenant's costs and damages pursuant to Section 40.2

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                  above exceed Landlord's share of the delay damages from
                  Landlord's Contractor (as specified in Section 40.3 above and
                  after crediting Tenant as provided in Section 5.3), then
                  Tenant shall be entitled to pursue all available remedies
                  against Landlord to collect such excess costs and damages
                  (together with interest on such sums at the rate of Bank of
                  America's "reference rate" plus 3% per annum), including,
                  without limitation, the right to make a credit offset against
                  the next rent payment(s) owing on this Lease to the extent of
                  such sums owing to Tenant. Prior to exercising such offset
                  right, Tenant shall first attempt to satisfy Landlord's
                  obligation to compensate Tenant under this Section 40 through
                  the sums to be received pursuant to Section 40.3 and any
                  remaining loan proceeds available from the New Loan."

                  37.      The second sentence of Section 1.1.1 of Exhibit "B"
to the Lease is hereby amended and restated as follows:

                  "If the Project Architect does not perform satisfactorily,
                  Tenant reserves the right to replace McGraw Baldwin Architects
                  with another qualified architectural firm mutually approved by
                  both Tenant and Landlord and Landlord's Mortgagee, which
                  approval shall not be withheld unreasonably."

                  38.      The fourth and fifth sentences of Section 1.5.1 of
Exhibit "B" to the Lease are hereby amended and restated in their entirety as
follows:

                  "All work shall be in accordance with all City, County, State
                  and Federal ordinances, rules and regulations relating
                  thereto. Any approval given by Landlord or Landlord's
                  Mortgagee shall not constitute a representation or warranty by
                  Landlord or Landlord's Mortgagee that the approved item
                  complies with applicable building codes or governmental
                  regulations, or that the item is suitable for the intended
                  use, or that the item is in compliance with the Improvement
                  Plans."

                  39.      The second sentence of Section 1.6.3 of Exhibit "B"
to the Lease is hereby amended by adding thereto at the end thereof the phrase
"in accordance with applicable law."

                  40.      The last sentence of Section 1.7.9 of Exhibit'"B" to
the Lease is hereby amended by adding thereto at the end thereof the following:

                  "provided, however, the insurance limit, the deductible
                  amounts, and the insurance carrier size shall not be less than
                  as specified in Section 19 of the Lease."

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<PAGE>

                  41.      The third line of Section 1.8 of Exhibit "B" to the
Lease is hereby amended by adding after the word "Landlord" the phrase "and
Landlord's Mortgagee."

                  42.      The second line of Section 1.8.1 of Exhibit "B" to
the Lease is hereby amended by adding after the word "Landlord" the phrase "and
Landlord's Mortgagee."

                  43.      The seventh line of Section 3.1 of Exhibit "B" to the
Lease is hereby amended and restated as follows:

                  "... City, County, State and Federal ordinances, rules and
                  regulations relating ..."

                  44.      Section 3.1 of Exhibit "B" to the Lease is further
amended by adding at the end thereof the phrase "comparable to the insurance as
specified in Section 1.7.9 above."

                  45.      Section 4.1.2 of Exhibit "B" to the Lease is hereby
amended by adding thereto at the end thereof the following sentence:

                  "Pursuant to the terms of the Loan from Landlord's Mortgagee,
                  and as specified in Section 3.4 of the Lease, Landlord and
                  Tenant acknowledge that union labor is to be used for
                  constructing the improvements within the criteria set forth in
                  Section 3.4 of the Lease."

                  46.      Paragraph 2 to Schedule 4 to Exhibit "B" to the Lease
is hereby amended by adding thereto at the end thereof the following provision:

                           "Tenant shall keep the construction validation
                  current throughout the term of the Lease, and provide to
                  Landlord all supporting documentation for the ongoing
                  construction validation. Tenant shall not allow the
                  construction validation of the pilot plant to lapse at any
                  time during the Lease Term."

                  47.      Paragraph 2 of Exhibit "D" to the Lease is hereby
amended by adding thereto at the end thereof the following sentence:

                  "Tenant shall be entitled to a credit against the termination
                  fee payable pursuant to this Paragraph for all unreimbursed
                  amounts due Tenant pursuant to the provisions of Paragraphs
                  5.3 and 40 of the Lease as well as for all amounts then
                  outstanding under the promissory note from Landlord to Tenant
                  dated

                                      -11-

<PAGE>

                  November 25, 1992, in the amount of $3,200,000.00, but only
                  to the extent of any excess of such termination fee over the
                  then unpaid balance of the loan from Landlord's Mortgagee."

         IN WITNESS WHEREOF, the parties hereto have executed this agreement as
of the date first set forth above.

                                        TORREY SORRENTO INC.,
                                        a California corporation

                                        By: /s/ [ILLEGIBLE]
                                            -----------------------------

                                        IDEC PHARMACEUTICALS CORPORATION,
                                        a California corporation

                                        BY: /s/ Phillip Schneider
                                            -----------------------------
                                            Vice President
                                      -12-

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