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                                                                    Exhibit 10.1

                                                                  Execution Copy

                                PLEDGE AGREEMENT

     This PLEDGE AGREEMENT (this "Agreement") is made and entered into as of
July 23, 2003 by and among Medarex, Inc., a New Jersey corporation (the
"Grantor"), having its principal executive offices at 707 State Road #206,
Princeton, New Jersey 08540 and Wilmington Trust Company, having an office at
1100 North Market Street, Wilmington, Delaware 19890, (i) in its capacity as
trustee (the "Trustee") for the holders (the "Holders") of the Notes (as
hereinafter defined) issued by the Grantor under the Indenture referred to below
and (ii) in its capacity, as securities intermediary (in such capacity, the
"Pledged Securities Intermediary") through the office of its affiliate in New
York c/o: Wilmington Trust, FSB, 520 Madison Avenue, 33rd Floor, New York, New
York 10022 (the "Account Office") with respect to the Pledge Account (as
hereinafter defined). Capitalized terms used herein and not otherwise defined
herein shall have the meanings given to such terms in the Indenture.

                               W I T N E S S E T H

     WHEREAS, the Grantor and the Trustee have entered into that certain
Indenture dated as of the date hereof (as amended, restated, supplemented or
otherwise modified from time to time, the "Indenture"), pursuant to which the
Grantor is issuing on the date hereof $125,000,000 in aggregate principal amount
of its 4.25% Convertible Senior Notes due August 15, 2010 (the "Notes"); and

     WHEREAS, subject to the terms of this Agreement, the Pledged Securities
Intermediary has established for the Grantor, as beneficial owner, a securities
account (the "Pledge Account") at the Account Office, registered in the name of
the Trustee, as entitlement holder, and designated as Account No. 62067-1,
Reference: "Medarex, Inc. 4.25% Notes - Pledged Securities Intermediary
Account"; and

     WHEREAS, the Grantor has agreed to purchase or cause the purchase of
security entitlements with respect to the portfolio of U. S. treasury securities
identified by CUSIP number in Schedule I hereto (such security entitlements
being, collectively, the "Pledged Securities"), for the account of the Pledged
Securities Intermediary for credit to the Pledge Account, in an amount that will
be sufficient, upon receipt of the scheduled interest and principal payments in
respect thereof, to provide for the payment in full of the first six scheduled
interest payments due on the Notes; and

     WHEREAS, to secure the obligations of the Grantor under the Indenture and
the Notes to pay in full each of the first six scheduled interest payments on
the Notes and to pay in full all of the principal, premium, if any (including
the Make-Whole Payment, if any, as such term is defined in the Indenture) and
interest (including Liquidated Damages, if any, as such term is defined in the
Indenture) on the Notes and all other amounts payable by the Grantor under the
Indenture in the event that the Notes or any principal thereof or premium, if
any (including the Make-Whole Payment), thereon becomes due and payable prior to
such time as the first six scheduled interest payments thereon shall have been
paid in full (collectively, the "Obligations"), the Grantor has agreed (i) to
grant to the Trustee, for its benefit and the ratable benefit of the Holders of
the Notes, a security interest in the Pledge Account and all cash, Pledged
Securities and other Collateral (as hereinafter defined) from time to time
deposited therein or credited thereto and (ii) to execute and deliver this
Agreement in order to secure the payment and performance by the Grantor of all
the Obligations; and;

     WHEREAS, it is a condition precedent to the purchase of the Notes by the
initial Holders thereof that the Grantor shall have granted the security
interests contemplated by this Agreement; and

     WHEREAS, unless otherwise defined herein or in the Indenture, terms used
herein that are defined in Article 8 or 9 of the Uniform Commercial Code as in
effect in the State of New York (the "UCC") are used herein as therein defined:

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     NOW, THEREFORE, in consideration of the mutual promises herein contained,
and in order to induce the initial Holders to purchase the Notes, the Grantor
hereby agrees with the Trustee, for the benefit of the Trustee and for the
ratable benefit of the Holders of the Notes, and with the Pledged Securities
Intermediary as follows:

     SECTION 1.   Grant of Security Interest. The Grantor hereby grants to the
Trustee, for its benefit and for the ratable benefit of the Holders of the
Notes, in its capacity as Trustee under the Indenture, a security interest in
and to all of the Grantor's right, title and interest in, to and under the
following, in each case whether now owned or hereafter acquired, wherever
located and whether now or hereafter existing (hereinafter collectively referred
to as the "Collateral"):

     (a)  the Pledge Account;

     (b)  all cash or credit balances from time to time deposited in or credited
to the Pledge Account;

     (c)  the Pledged Securities and all other financial assets (including
certificated and uncertificated securities) and security entitlements from time
to time deposited in, credited to, or created or otherwise carried in the Pledge
Account;

     (d)  all interest, dividends, cash, instruments and other property from
time to time received, receivable or otherwise distributed in respect of or in
exchange for any or all of the Collateral;

     (e)  all securities (whether certificated or uncertificated) or other
financial assets, security entitlements, securities accounts, accounts, general
intangibles, instruments, documents, cash or deposit accounts representing or
evidencing any or all of the Collateral; and

     (f)  to the extent not covered by clauses (a) through (e) above, all
proceeds of any and all of the foregoing Collateral (including, without
limitation, proceeds that constitute property of the types described in clauses
(a) through (e) above).

     SECTION 2.   Secured Obligations. This Agreement and the grant of a
security interest in the Collateral secure the prompt and complete payment and
performance when due (whether at stated maturity, by acceleration, upon
redemption or otherwise) of all Obligations now or hereafter existing, whether
for principal, premium (including the Make-Whole Payment, if any), interest
(including Liquidated Damages, if any), fees, indemnities or otherwise, and all
obligations of the Grantor now or hereafter existing under this Agreement (all
such Obligations and such other obligations being, collectively, the "Secured
Obligations"). Without limiting the generality of the foregoing, this Agreement
and the grant of a security interest in the Collateral hereunder secure, to the
fullest extent permitted by applicable law, the payment of all amounts that
constitute part of the Secured Obligations and that would be owed by the Grantor
to the Trustee or the Holders under the Notes or the Indenture but for the fact
that they are unenforceable or not allowable due to the existence of a
bankruptcy, reorganization or similar proceeding involving the Grantor.

     SECTION 3.   Maintaining the Pledge Account. Prior to or concurrently with
the execution and delivery hereof and for so long as any Secured Obligation
shall remain outstanding,

     (a)  the Trustee shall establish and maintain (and the Pledged Securities
Intermediary shall maintain and administer in accordance with this Agreement)
the Pledge Account with the Pledged Securities Intermediary at the Account
Office in accordance with the terms of this Agreement. The Pledge Account shall
at all times be under the sole dominion and control of, and shall at all times
be segregated from any other custodial, collateral or other accounts maintained
by, or under the dominion and control of, the Trustee;

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     (b)  it shall be a term and condition of the Pledge Account,
notwithstanding any term or condition to the contrary in any other agreement
relating to the Pledge Account, and except as otherwise provided by the
provisions of Section 5 and Section 15.9 of this Agreement, that no Collateral
(including proceeds thereof) shall be paid or released from the Pledge Account
to or for the account of, or withdrawn by or for the account of, and no
entitlement orders with respect to any of the Collateral shall be given to the
Pledged Securities Intermediary by, the Grantor or any other Person other than
the Trustee as provided herein;

     (c)  subject to the provisions of this Agreement, the Pledge Account shall
be registered in the name of the Trustee on the books and records of the Pledged
Securities Intermediary, the Trustee shall be identified on such books and
records as the entitlement holder with respect to all security entitlements in
all financial assets from time to time held in or credited to the Pledge
Account, and the Trustee shall have the sole right to (i) deliver entitlement
orders with respect to the Pledge Account and any Collateral from time to time
credited thereto, deposited therein or represented thereby or (ii) make
withdrawals from the Pledge Account or otherwise exercise any other rights with
respect to any Collateral from time to time credited thereto or on deposit
therein; and

     (d)  the Pledge Account shall be subject to such applicable laws, and such
applicable regulations of any appropriate banking or governmental authority, as
may now or hereafter be in effect, including without limitation any applicable
regulations of the Board of Governors of the Federal Reserve System.

     SECTION 4.   Acquisition of Pledged Securities for Credit to the Pledge
Account.

     (a)  On or prior to the date hereof, the Grantor shall purchase or cause
the purchase of the Pledged Securities for the account of the Pledged Securities
Intermediary for credit to the Pledge Account.

     (b)  Upon transfer or credit of the Pledged Securities to the Pledged
Securities Intermediary, as confirmed to the Pledged Securities Intermediary by
the Federal Reserve Bank of New York or another securities intermediary at which
the Pledged Securities Intermediary maintains a securities account, the Pledged
Securities Intermediary shall make appropriate book entries indicating that the
Pledged Securities have been credited to and are held in the Pledge Account.

     SECTION 5.   Disbursements From the Pledge Account; Transfers of Additional
Amounts to the Pledge Account.

     (a)  Not less than three Business Days prior to the due date of any of the
first six scheduled interest payments on the Notes, the Grantor may, pursuant to
written instructions given by the Grantor to the Trustee (each an "Issuer
Order"), instruct the Trustee to direct the Pledged Securities Intermediary to
release from the Pledge Account, and pay to the Holders of the Notes as of the
applicable Regular Record Date, proceeds of the Pledged Securities sufficient to
provide for payment in full of such interest then due on the Notes. Upon receipt
of an Issuer Order, the Trustee will direct the Pledged Securities Intermediary
to release funds from (and to the extent of) proceeds of the Pledged Securities
in the Pledge Account in an amount sufficient to provide for the payment in full
of such interest then due on the Notes, as instructed in such Issuer Order, and
to transfer such funds to the Holders of the Notes in accordance with the
payment provisions of the Indenture. Nothing in this Section 5 shall affect the
Trustee's rights to direct the application of the Collateral to the payment of
amounts due on the Notes upon acceleration thereof in accordance with the terms
of the Indenture.

     (b)  If the Grantor makes all or any portion of any interest payment for
which the Collateral is security from a source of funds other than the Pledge
Account ("Grantor Funds"), the Grantor may, after payment in full of such
interest payment, instruct the Trustee, pursuant to an Issuer Order, to direct
the Pledged Securities Intermediary to release to the Grantor, or to another
party designated by the Grantor in

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such Issuer Order (the "Grantor's Designee"), proceeds from the Pledge Account
in an amount that, in the discretion of the Grantor, is less than or equal to
the amount of Grantor Funds applied to such interest payment; provided that,
after giving effect to such release, the scheduled interest and principal
payments in respect of the Pledged Securities remaining in the Pledge Account,
together with any cash remaining in the Pledge Account, equal or exceed the
amount necessary to provide for the timely payment in full of interest on the
Notes for as many of the first six scheduled interest payments as shall then
remain. Upon (i) receipt by the Trustee of such Issuer Order and (ii)
confirmation by the Trustee of the payment in full of such interest payment
(from such Grantor Funds and, if necessary, additional funds released from the
Pledge Account in accordance with Section 5(a) hereof), the Trustee shall direct
the Pledged Securities Intermediary to release funds from (and to the extent of)
proceeds of the Pledged Securities in the Pledge Account and to transfer such
funds to the Grantor or the Grantor's Designee, as the case may be, as
instructed in such Issuer Order as soon as practicable after such conditions are
satisfied.

     (c)  If at any time the scheduled interest and principal payments in
respect of the Pledged Securities then credited to the Pledge Account, together
with any cash then held in the Pledge Account, exceed 100% of the amount
necessary (which shall be certified in writing by an Officer of the Company or,
if such amount, together with all other amounts disbursed from the Pledge
Account in the preceding 12-month period, equals or exceeds $100,000, by a
nationally recognized firm of independent accountants selected by the Grantor
and delivered to the Trustee) to provide for the payment in full, when due, of
the first six scheduled interest payments on the Notes (or such number of the
first six scheduled interest payments on the Notes as shall then remain, as the
case may be), the Grantor may instruct the Trustee, pursuant to an Issuer Order,
to direct the Pledged Securities Intermediary to release any such excess amount
to the Grantor or to the Grantor's Designee. Upon receipt of such Issuer Order
(which shall be accompanied by a certificate in accordance with, and meeting the
requirements of, the provisions of Section 314(d) of the TIA or, if the amount
to be released from the pledge, together with all other amounts disbursed from
the Pledge Account in the preceding 12-month period, equals or exceeds $100,000,
by a certificate of such nationally recognized firm of independent accountants
stating that the scheduled interest and principal payments in respect of the
Pledged Securities credited to the Pledge Account, together with any cash held
in the Pledge Account, in each case after giving effect to such release, equal
or exceed 100% of the amount necessary to provide for the payment in full, when
due, of such remaining scheduled interest payments on the Notes), the Trustee
shall instruct the Pledged Securities Intermediary to release funds from (and to
the extent of) proceeds of such Pledged Securities in accordance with such
Issuer Order and the accompanying certificate and to transfer such funds to the
Grantor or the Grantor's Designee, as the case may be.

     (d)  Upon the release of any Collateral from the Pledge Account in
accordance with the terms of this Section 5, whether upon release of proceeds of
Collateral to the Holders as payment of interest or upon release of proceeds of
Collateral to the Grantor or the Grantor's Designee as provided in Section 5(b)
or Section 5(c), the security interest evidenced by this Agreement in such
released Collateral will automatically terminate and be of no further force and
effect.

     (e)  At least three Business Days prior to the due date of each of the
first six scheduled interest payments on the Notes, the Grantor shall give the
Trustee notice (by Issuer Order) as to whether such interest payment will be
made pursuant to Section 5(a) or 5(b) above and the respective amounts of
interest that will be paid from the Pledge Account and from Grantor Funds (it
being understood that the failure by the Grantor to provide an Issuer Order
shall not constitute an Event of Default). Any Grantor Funds to be used to make
any interest payment (or portion thereof) shall be delivered to the Trustee, in
immediately available funds, prior to 12:00 p.m. (New York City time) on such
interest payment date. If no such notice is given or such Grantor Funds have not
been so delivered, the Trustee will act pursuant to Section 5(a) above as if it
had received an Issuer Order pursuant thereto for the payment in full of the
interest then due and payable from the proceeds of Pledged Securities in the
Pledge Account.

     (f)  If on any interest payment date there are insufficient proceeds of
Pledged Securities in the Pledge Account to make the scheduled payment of
interest due on such date (after taking into account any

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Grantor Funds delivered to the Trustee as provided in Section 5(b) above), the
Trustee shall direct the Pledged Securities Intermediary to liquidate Collateral
in the Pledge Account to the extent necessary to pay, in full, such scheduled
payment of interest.

     (g)  Nothing contained in this Agreement (including without limitation the
provisions hereof regarding the delivery of Issuer Orders by the Grantor to the
Trustee) shall (i) afford the Grantor any right to issue entitlement orders to
the Pledged Securities Intermediary or any other Person with respect to the
Pledge Account or any security entitlement in respect of the Pledged Securities,
or otherwise afford the Grantor control of the Pledge Account or any such
security entitlement, or (ii) otherwise give rise to any rights of the Grantor
with respect to the Pledge Account, the Pledged Securities, or any security
entitlement thereto, other than the Grantor's rights under this Agreement as the
beneficial owner of Collateral pledged to and subject to the exclusive dominion
and control (subject to the Trustee's obligations to comply with Sections 5(a)
through (f) and Section 15.9 hereof) of the Trustee in its capacity as such (and
not as a securities intermediary). The Grantor acknowledges, confirms and agrees
that the Trustee has been granted a security interest in the Pledged Securities
for its benefit as Trustee under the Indenture and for the ratable benefit of
the Holders of the Notes and not in its capacity as a securities intermediary.

     (h)  Anything contained herein to the contrary notwithstanding, prior to
any release of any Collateral to the Grantor or the Grantor's Designee, the
Grantor shall deliver to the Trustee such certificates, opinions or other
documents as may be required by the Indenture or the TIA in connection with such
release and shall otherwise comply with the requirements of the Indenture and
the TIA applicable thereto.

     (i)  If at any time the Grantor is obligated to pay any amount to the
Trustee pursuant to the terms of this Agreement and the Trustee charges such
amount against the Pledge Account with the result that the scheduled interest
and principal payments in respect of the Pledged Securities then credited to the
Pledge Account, together with any cash then held in the Pledge Account, are less
than 100% of the amount necessary to provide for the payment in full, when due,
of the first six scheduled interest payments on the Notes (or such number of the
first six scheduled interest payments on the Notes as shall then remain, as the
case may be), the Grantor shall deposit cash into the Pledge Account in the
amount of such deficiency and shall deliver to the Trustee a certificate signed
by one of its Officers (as defined in the Indenture) stating that the scheduled
interest and principal payments in respect of the Pledged Securities credited to
the Pledge Account, together with any cash held in the Pledge Account, in each
case after giving effect to such deposit by the Grantor, equal or exceed 100% of
the amount necessary to provide for the payment in full, when due, of such
remaining scheduled interest payments on the Notes.

     (j)  Neither the Trustee nor the Pledged Securities Intermediary shall be
liable for any disbursement made or other action taken in accordance with an
Issuer Order. In no event shall either of the Pledged Securities Intermediary or
the Trustee in its role hereunder be liable for any special, indirect or
consequential loss or damage of any kind whatsoever (including but not limited
to lost profits), except as a result of its gross negligence or willful
misconduct.

     SECTION 6.   Securities Intermediary. Wilmington Trust Company, as Pledged
Securities Intermediary, hereby represents and warrants to, and agrees with the
Grantor and the Trustee, as follows:

     (a)  It is a securities intermediary as of the date hereof and, for so long
as this Agreement remains in effect and Wilmington Trust Company is acting as
the Pledged Securities Intermediary hereunder, it shall remain a securities
intermediary and shall at all times act in such capacity with respect to the
Trustee, the Pledge Account and all other Collateral.

     (b)  The Pledge Account is and will be maintained as a securities account.

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     (c)  Each item of property (whether cash, certificated or uncertificated
securities, security certificates, security entitlements or any other property
whatsoever) credited to the Pledge Account shall be treated as a financial
asset.

     (d)  All financial assets in registered form or payable to, or to the order
of, any Person and credited to the Pledge Account shall be registered in the
name of, payable to or to the order of, or endorsed to, the Pledged Securities
Intermediary, and in no case during the term of this Agreement will any
financial asset credited to the Pledge Account be registered in the name of,
payable to or to the order of, or endorsed to, the Grantor, except to the extent
the foregoing have been subsequently endorsed by the Grantor to the Pledged
Securities Intermediary or in blank.

     (e)  It (i) shall, upon written direction from the Trustee, as entitlement
holder with respect to the Pledge Account, the Pledged Securities and all other
Collateral, and without further consent from the Grantor, comply with all
instructions, entitlement orders and directions of any kind originated by the
Trustee concerning the Collateral, including, without limitation, directions to
liquidate or otherwise dispose of the Collateral as and to the extent directed
by the Trustee and to pay over to the Trustee, or as otherwise directed by the
Trustee, all proceeds and other value therefrom or otherwise distributed with
respect thereto, without any set-off or deduction, and (ii) shall not, except as
otherwise directed in writing by the Trustee, as entitlement holder with respect
to the Pledge Account, the Pledged Securities and all other Collateral, comply
or agree to comply with any instructions, entitlement orders or directions of
any kind that are originated by the Grantor or any other Person with respect to
any of the Collateral.

     (f)  Except for the claims and interests of the Trustee and the Holders
under this Agreement and the rights of the Grantor vis-a-vis the Trustee
hereunder, it does not know of any claim to or security interest or other
interest in the Collateral.

     (g)  It hereby waives its rights to set off any obligations of the Grantor
to it against any or all of the Collateral, and hereby agrees that any and all
liens, encumbrances, claims or security interests which it may have against the
Collateral, either now or in the future, are and shall be subordinate and junior
in right of payment to the prior payment in full of all Secured Obligations.

     SECTION 7.   Representations and Warranties. The Grantor hereby represents
and warrants that:

     (a)  The execution and delivery by the Grantor of, and the performance by
the Grantor of its obligations under, this Agreement will not contravene any
provision of applicable law or the articles of incorporation or by-laws of the
Grantor or any material agreement or other material instrument binding upon the
Grantor or any judgment, order or decree of any governmental body, agency or
court having jurisdiction over the Grantor, or result in the creation or
imposition of any lien on any assets of the Grantor, except for the security
interests granted under this Agreement.

     (b)  No consent of any other Person and no approval, authorization or order
of, action by or qualification with, any governmental authority, regulatory
body, agency or other third party is required (i) for the execution, delivery or
performance by the Grantor of its obligations under this Agreement or (ii) for
the grant by the Grantor of the security interests created by this Agreement. To
the best of Grantor's knowledge, no consent of any other Person and no approval,
authorization or order of, action by or qualification with, any governmental
authority, regulatory body, agency or other third party is required for the
exercise by the Trustee of the rights provided for in this Agreement or the
remedies in respect of the Collateral pursuant to this Agreement.

     (c)  The Grantor is the beneficial owner of the Collateral, free and clear
of any lien or claim of any Person (except for the security interests created by
this Agreement and any lien arising under the Indenture in favor of the
Trustee). The Grantor has not at any time transferred any of the Collateral to
any

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Person other than the Trustee or encumbered any of the Collateral with a lien in
favor of any other Person. No financing statement or instrument similar in
effect covering all or any part of the Grantor's interest in any of the
Collateral is on file in any public or recording office, other than the
financing statements filed pursuant to this Agreement. The Grantor has no trade
names.

     (d)  This Agreement has been duly authorized, executed and delivered by the
Grantor and constitutes a valid and binding agreement of the Grantor,
enforceable against the Grantor in accordance with its terms, except as the
enforceability hereof may be limited by applicable bankruptcy, insolvency or
similar laws affecting creditors' rights generally or by equitable principles of
general applicability.

     (e)  Upon the transfer to the Pledged Securities Intermediary of the
Pledged Securities, the crediting thereof to the Pledge Account in accordance
with Section 4 above and the execution and delivery of this Agreement by all of
the parties hereto, the grant of a security interest in the Collateral pursuant
to this Agreement for the benefit of the Trustee and the Holders of the Notes
will create a valid and perfected first priority security interest in such
Collateral securing the payment of the Secured Obligations.

     (f)  There are no legal or governmental proceedings pending or, to the best
of the Grantor's knowledge, threatened to which the Grantor is a party or to
which any of the properties of the Grantor is subject that would adversely
affect in any material respect the power or ability of the Grantor to perform
its obligations under this Agreement or to consummate the transactions
contemplated hereby.

     (g)  The pledge of the Collateral pursuant to this Agreement is not
prohibited by any law or governmental regulation (including, without limitation,
Regulations U and X of the Board of Governors of the Federal Reserve System)
applicable to the Grantor.

     (h)  To the best of Grantor's knowledge, no Default or Event of Default
exists.

     (i)  The Grantor's exact legal name is that indicated on the signature page
hereof.

     (j)  The Grantor is a corporation organized in the State of New Jersey.

     (k)  The Grantor's place of business or, if more than one, its chief
executive office as well as the Grantor's mailing address is as is set forth in
Section 15.1 hereof.

     SECTION 8.   Further Assurances.

     (a)  The Grantor agrees that from time to time, it will, at its own
expense, promptly upon reasonable request by the Trustee, execute and deliver or
cause to be executed and delivered, or use its commercially reasonable efforts
to procure, all assignments, instruments and other documents, all in form and
substance reasonably satisfactory to the Trustee, deliver any instruments to the
Trustee and take any other actions that may be necessary or, in the reasonable
opinion of the Trustee, desirable to perfect, continue the perfection of, or
protect the first priority of the Trustee's security interest in and to the
Collateral, to protect the Collateral against the rights, claims, or interests
of third Persons (other than any such rights, claims or interests created by or
arising through the Trustee) or to effect the purposes of this Agreement.

     (b)  The Grantor hereby authorizes the Trustee to file any financing or
continuation statements with respect to the Collateral without the signature of
the Grantor (to the extent permitted by applicable law); provided, however, that
the Grantor shall not be relieved of any of its obligations under Section 8(a)
or 8(d) hereof. A photocopy or other reproduction of this Agreement or any
financing statement covering the Collateral or any part thereof shall be
sufficient as a financing statement where permitted by law.

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     (c)  The Grantor will furnish to the Trustee from time to time statements
and schedules further identifying and describing the Collateral and such other
reports in connection with the Collateral as the Trustee may reasonably request,
all in reasonable detail.

     (d)  The Grantor will promptly pay all costs and expenses reasonably
incurred in connection with any of the foregoing within 30 days of receipt of an
invoice therefor. The Grantor also agrees, whether or not requested by the
Trustee, to take all actions that are necessary to perfect and to continue the
perfection of, and to protect the first priority of, the Trustee's security
interest in and to the Collateral, including the filing of all necessary
financing and continuation statements, and to protect the Collateral against the
rights, claims or interests of third Persons (other than any such rights, claims
or interests created by or arising through the Trustee).

     (e)  The Grantor hereby irrevocably authorizes the Trustee at any time and
from time to time to file in any Uniform Commercial Code jurisdiction any
initial financing statements and amendments thereto that (x) indicate the
Collateral as being of an equal or lesser scope or with greater detail, and (y)
contain any other information required by part 5 of Article 9 of the Uniform
Commercial Code of the appropriate jurisdiction for the sufficiency or filing
office acceptance of any financing statement or amendment; provided that the
Trustee shall have no obligation to perform any of the foregoing actions other
than those expressly provided herein or in the Indenture.

     (f)  The Pledged Securities Intermediary covenants and agrees with the
Grantor and the Trustee that for so long as the Pledged Securities Intermediary
holds assets in the Pledge Account, the Pledged Securities Intermediary will, as
soon as reasonably practicable, certify in writing the aggregate dollar value of
the assets held in such Pledge Account on a monthly basis, as of the Grantor's
fiscal month end or at such other time as the parties may mutually agree. The
Grantor will provide the Pledged Securities Intermediary with a schedule of its
fiscal months as soon as such schedule becomes reasonably available.

     (g)  If the Grantor fails to perform any agreement contained herein, the
Trustee may but shall not be required to perform, or cause performance of, such
agreement, and the reasonable expenses of the Trustee incurred in connection
therewith shall be payable by the Pledgor under Section 14 hereof.

     SECTION 9.   Covenants. The Grantor covenants and agrees with the Trustee
and the Holders of the Notes that from and after the date of this Agreement
until the earlier of (x) payment in full in cash of each of the first six
scheduled interest payments due on the Notes under the terms of the Indenture or
(y) payment in full in cash of all Secured Obligations due and owing under the
Indenture and the Notes in the event such Secured Obligations become due and
payable prior to the payment in full of the first six scheduled interest
payments on the Notes:

     (a)  it will not (and will not purport to) sell or otherwise dispose of, or
grant any option, right or warrant with respect to, any of the Collateral or its
beneficial interest therein, and it will not create or permit to exist any lien
or other adverse interest in or with respect to its beneficial interest in any
of the Collateral (except for the security interests granted under this
Agreement and any lien arising under the Indenture in favor of the Trustee);

     (b)  it will not (i) enter into any agreement or understanding that
restricts or inhibits or purports to restrict or inhibit the Trustee's rights or
remedies hereunder, including without limitation the Trustee's right to sell or
otherwise dispose of the Collateral, or (ii) fail to pay or discharge when due
any tax, assessment or levy of any nature with respect to its beneficial
interest in the Collateral not later than five days prior to the date of any
proposed sale under any judgment, writ or warrant of attachment with respect to
such beneficial interest; and

                                       -8-

<PAGE>

     (c)  it will not, without providing at least five days prior written notice
to the Trustee, change its name, its place of business or, if more than one,
chief executive office, or its mailing address or organizational identification
number and will not change its type of organization, jurisdiction of
organization or other legal structure.

     SECTION 10.  Power of Attorney. In addition to all of the powers granted to
the Trustee pursuant to the Indenture, the Grantor hereby appoints and
constitutes the Trustee as the Grantor's attorney-in-fact (with full power of
substitution), with full authority in the place and stead of the Grantor and in
the name of the Grantor or otherwise, from time to time in the Trustee's
reasonable discretion to take any action and to execute any instrument that the
Trustee may deem necessary or advisable to accomplish the purposes of this
Agreement, including, without limitation:

     (a)  to ask for, demand, collect, sue for, recover, compromise, receive and
give acquittance and receipt for moneys due and to become due under or in
respect of any of the Collateral,

     (b)  to receive, indorse and collect any drafts or other instruments,
documents and chattel paper,

     (c)  to file any claims or take any action or institute any proceedings
that the Trustee may reasonably deem necessary or desirable for the collection
of any of the Collateral or otherwise to enforce the rights of the Trustee with
respect to any of the Collateral, and

     (d)  to pay or discharge any taxes or liens levied or placed upon the
Collateral, the legality or validity thereof and the amounts necessary to
discharge the same all as determined by the Trustee in its sole discretion, it
being understood that any such payments made by the Trustee shall become part of
the Secured Obligations of the Grantor to the Trustee, and shall be due and
payable immediately upon demand;

provided, however, that the Trustee shall have no obligation to perform any of
the foregoing actions. The Trustee's authority under this Section 10 shall
include, without limitation, the authority to endorse and negotiate any checks
or instruments representing proceeds of Collateral in the name of the Grantor,
execute and give receipt for any certificate of ownership or any document
constituting Collateral, transfer title to any item of Collateral, authorize the
filing of any financing statements (to the extent permitted by applicable law)
or any other documents reasonably deemed necessary or appropriate by the Trustee
to preserve, protect or perfect the security interest in the Collateral and to
file the same, prepare, file and sign the Grantor's name on any notice of lien,
and to take any other actions arising from or incident to the powers granted to
the Trustee in this Agreement. This power of attorney is coupled with an
interest and is irrevocable by the Grantor.

     SECTION 11.  No Assumption of Duties; Reasonable Care. The rights and
powers conferred on the Trustee hereunder are solely to preserve and protect the
security interest of the Trustee and the Holders of the Notes in and to the
Collateral granted hereby and shall not be interpreted to, and shall not, impose
any duties on the Trustee in connection therewith other than those expressly
provided herein or in the Indenture or imposed under applicable law. Except as
provided herein, by applicable law or by the Indenture, the Trustee shall be
deemed to have exercised reasonable care in the custody and preservation of any
Collateral in its possession if the Collateral is accorded treatment
substantially equal to that which the Trustee accords similar property held by
itself for its own account, it being understood that the Trustee, in its
capacity as such, shall not have any responsibility for (a) ascertaining or
taking action with respect to calls, conversions, exchanges, maturities or other
matters relative to any Collateral, whether or not the Trustee has or is deemed
to have knowledge of such matters, (b) taking any necessary steps to preserve
rights against any parties with respect to any Collateral or (c) investing or
reinvesting any of the Collateral or any loss on any investment. Without
limiting any rights of the Trustee hereunder, the rights and limitations upon
the liability of the Trustee set forth in Article VI of the Indenture are
expressly

                                       -9-

<PAGE>

incorporated herein and made a part hereof and shall extend to the role of the
Trustee as Pledged Securities Intermediary.

     SECTION 12.  Indemnity. The Grantor shall indemnify, hold harmless and
defend the Trustee, the Pledged Securities Intermediary and each of their
respective directors, officers, agents and employees, from and against any and
all claims, actions, obligations, liabilities and expenses, including defense
costs, investigative fees and costs, and legal fees and damages arising from
their execution of or performance under this Agreement, except to the extent
that such claim, action, obligation, liability or expense is directly
attributable to the bad faith, gross negligence or willful misconduct of such
indemnified person. This indemnification shall survive the termination of this
Agreement.

     SECTION 13.  Remedies Upon Event of Default. If any Event of Default shall
have occurred and be continuing:

     (a)  The Trustee may exercise, in addition to all other rights given by law
or by this Agreement or the Indenture, all of the rights and remedies with
respect to the Collateral of a secured party under the Uniform Commercial Code
as in effect from time to time in any relevant jurisdiction and also may,
without notice except as specified below, (i) sell, redeem or liquidate any of
the Collateral, (ii) transfer any or all of the Collateral to any account
designated by the Trustee, including an account or accounts established in the
Trustee's name, (iii) register title to any Collateral in any name specified by
the Trustee, including the name of the Trustee or any of its nominees or agents,
without reference to any interest of the Grantor, or (iv), sell the Collateral
or any part thereof in one or more parcels at any broker's board or at public or
private sale, in one or more sales or lots, at any of the Trustee's offices or
elsewhere, for cash, on credit or for future delivery, and upon such other terms
as the Trustee may deem commercially reasonable. The Grantor agrees that the
Collateral is of a type customarily sold on recognized markets and, accordingly,
that no notice to any Person is required before any sale of any of the
Collateral pursuant to the terms of this Agreement; provided, however that,
without prejudice to the foregoing, to the extent notice of any such sale shall
be required by law, the Grantor agrees that at least ten days' notice to the
Grantor of the time and place of any public sale or the time after which any
private sale is to be made shall constitute reasonable notification. The Trustee
shall not be obligated to make any sale of Collateral regardless of notice of
sale having been given. The Trustee may adjourn any public or private sale from
time to time by announcement at the time and place fixed therefor, and such sale
may, without further notice, be made at the time and place to which it was so
adjourned. The purchaser of any or all Collateral so sold shall thereafter hold
the same absolutely free from any claim, encumbrance or right of any kind
whatsoever created by or through the Grantor. Any sale of the Collateral
conducted in conformity with reasonable commercial practices of banks, insurance
companies, commercial finance companies, or other financial institutions
disposing of property similar to the Collateral shall be deemed to be
commercially reasonable. The Trustee or any Holder of Notes may, in its own name
or in the name of a designee or nominee, buy any of the Collateral at any public
sale and, if permitted by applicable law, at any private sale. All expenses
(including court costs and reasonable attorneys' fees, expenses and
disbursements) of, or incident to, the enforcement of any of the provisions
hereof shall be recoverable from the proceeds of the sale or other disposition
of the Collateral. If there are insufficient Pledged Securities together with
proceeds of Pledged Securities and other Collateral in the Pledge Account to
make any required payment on the Secured Obligations, the Grantor shall be
liable to the Trustee for any deficiency.

     (b)  All cash proceeds received by or on behalf of the Trustee in respect
of any sale of, collection from, or other realization upon all or any part of
the Collateral may, following the payment of the reasonable fees and expenses of
the Trustee, be held by the Trustee (or by the Pledged Securities Intermediary
on its behalf) as collateral for, and/or then or at any time thereafter applied
(after payment of any amounts payable to the Trustee pursuant to Section 14
hereof) in whole or in part by the Trustee as provided in clause SECOND of
Section 5.6 of the Indenture. Any surplus of such cash or cash proceeds held by
or on behalf of the Trustee and remaining after payment in full of all the
Secured Obligations shall be paid over as provided in clause THIRD of Section
5.6 of the Indenture.

                                       -10-

<PAGE>

     (c)  The Trustee may, without notice to the Grantor except as required by
law and at any time or from time to time, charge, set-off and otherwise apply
all or any part of the Secured Obligations against the Pledge Account or any
part thereof.

     (d)  The Grantor further agrees to use its commercially reasonable efforts
to do or cause to be done all such other acts as may be necessary to make such
sale or sales of all or any portion of the Collateral pursuant to this Section
13 valid and binding and in compliance with any and all other applicable
requirements of law. The Grantor further agrees that a breach of any of the
covenants contained in this Section 13 will cause irreparable injury to the
Trustee and the Holders of the Notes, that the Trustee and the Holders of the
Notes have no adequate remedy at law in respect of such breach and, as a
consequence, that each and every covenant contained in this Section 13 shall be
specifically enforceable against the Grantor and, to the fullest extent
permitted by law, the Grantor hereby waives and agrees not to assert any
defenses against an action for specific performance of such covenants except for
a defense that no Event of Default has occurred and is continuing.

     SECTION 14.   Expenses. The Grantor will promptly upon demand pay to the
Trustee and the Pledged Securities Intermediary the amount of any and all
reasonable expenses, including, without limitation, the reasonable fees,
expenses and disbursements of counsel, experts and agents retained by the
Trustee or the Pledged Securities Intermediary, as the case may be, that the
Trustee or the Pledged Securities Intermediary, as the case may be, may incur in
connection with (a) the review, negotiation and administration of this
Agreement, (b) the custody or preservation of, or the sale of, collection from,
or other realization upon, any of the Collateral, (c) the exercise or
enforcement of any of the rights of the Trustee and the Holders of the Notes
hereunder or (d) the failure by the Grantor to perform or observe any of the
provisions hereof.

     SECTION 15.   Miscellaneous Provisions.

     Section 15.1. Notices. Any notice or other communication given hereunder
shall be sufficiently given if in writing and delivered in person or mailed by
first class mail, commercial courier service or telecopier communication,
addressed as follows:

          IF TO THE GRANTOR:
          Medarex, Inc.
          707 State Road
          Princeton, New Jersey 08540
          Attention:  Senior Vice President, General Counsel and Secretary
          Fax: 609-430-4215

     IF TO THE TRUSTEE OR PLEDGED SECURITIES INTERMEDIARY:

          Wilmington Trust Company
          1100 North Market Street
          Wilmington, Delaware 19890
          Attention: Tom Morris
          Fax:  302-636-4140/4141

     With a copy to:

          Paul, Hastings, Janofsky & Walker LLP
          75 East 55/th/ Street
          New York, New York 10022
          Attention:  Charles H. Baker
          Fax:  212-319-4090

                                       -11-

<PAGE>

     All such notices and other communications shall, when mailed, delivered or
telecopied, respectively, be effective when deposited in the mails, delivered or
telecopied, respectively, addressed as aforesaid.

     Section 15.2.  No Adverse Interpretation of Other Agreements. This
Agreement may not be used to interpret another pledge, security or debt
agreement of the Grantor or any subsidiary thereof. No such pledge, security or
debt agreement (other than the Indenture) may be used to interpret this
Agreement.

     Section 15.3.  Severability. The provisions of this Agreement are
severable, and if any clause or provision shall be held invalid, illegal or
unenforceable in whole or in part in any jurisdiction, then, to the fullest
extent permitted by law, such invalidity or unenforceability shall affect in
that jurisdiction only such clause or provision, or part thereof, and shall not
in any manner affect such clause or provision in any other jurisdiction or any
other clause or provision of this Agreement in any jurisdiction.

     Section 15.4.  Headings. The headings in this Agreement have been inserted
for convenience of reference only, are not to be considered a part hereof and
shall in no way modify or restrict any of the terms or provisions hereof.

     Section 15.5.  Counterpart Originals. This Agreement may be signed in two
or more counterparts, each of which shall be deemed an original, but all of
which shall together constitute one and the same agreement.

     Section 15.6.  Benefits of Agreement. Nothing in this Agreement, express or
implied, shall give to any Person, other than the parties hereto and their
successors hereunder, and the Holders of the Notes, any benefit or any legal or
equitable right, remedy or claim under this Agreement.

     Section 15.7.  Amendments, Waivers and Consents. Any amendment or waiver of
any provision of this Agreement and any consent to any departure by the Grantor
from any provision of this Agreement shall be effective only if made or duly
given in compliance with all of the terms and provisions of the Indenture, and
then such waiver or consent shall be effective only in the specific instance and
for the specific purpose for which given, provided that an amendment or
supplement to this Agreement for the purposes contemplated by Section 16 hereof
may be entered into by the Grantor, the Trustee and the Pledged Securities
immediately without the consent of any Holder, so long as such amendment or
supplement is reasonably satisfactory in form and substance to the Grantor, the
Trustee and the Pledged Securities Intermediary. Neither the Trustee nor any
Holder of Notes shall be deemed, by any act, delay, indulgence, omission or
otherwise, to have waived any right or remedy hereunder or to have acquiesced in
any Event of Default or in any breach of any of the terms and conditions hereof.
Failure of the Trustee or any Holder of Notes to exercise, or delay in
exercising, any right, power or privilege hereunder shall not preclude any other
or further exercise thereof or the exercise of any other right, power or
privilege. A waiver by the Trustee or any Holder of Notes of any right or remedy
hereunder on any one occasion shall not be construed as a bar to any right or
remedy that the Trustee or such Holder would otherwise have on any future
occasion. The rights and remedies herein provided are cumulative, may be
exercised singly or concurrently and are not exclusive of any rights or remedies
provided by law.

     Section 15.8.  Interpretation of Agreement. To the fullest extent permitted
by applicable law, acceptance of or acquiescence in a course of performance
rendered under this Agreement shall not be relevant to determine the meaning of
this Agreement even though the accepting or acquiescing party had knowledge of
the nature of the performance and opportunity for objection.

     Section 15.9.  Continuing Security Interest; Termination.

     (a)  This Agreement shall create a continuing security interest in and to
the Collateral and shall, unless otherwise provided in this Agreement, remain in
full force and effect until the payment in full

                                       -12-

<PAGE>

in cash of the Secured Obligations. This Agreement shall be binding upon the
Grantor, its transferees, successors and assigns, and shall inure, together with
the rights and remedies of the Trustee hereunder, to the benefit of the Trustee,
the Holders of the Notes, the Pledged Securities Intermediary and their
respective successors, transferees and assigns.

     (b)  This Agreement (other than Grantor's obligations under Sections 12 and
14 hereof) shall terminate upon the earlier of (i) the payment in full in cash
of the Secured Obligations and (ii) the payment in full in cash of the first six
scheduled interest payments on all of the Notes. At such time, the Trustee
shall, pursuant to an Issuer Order, direct the Pledged Securities Intermediary
to promptly transfer to the Grantor all of the Collateral hereunder that has not
been sold, disposed of, retained or applied by or on behalf of the Trustee in
accordance with the terms of this Agreement and the Indenture and take all other
actions that are necessary to release the security interest created by this
Agreement in and to the Collateral, including the execution and delivery of all
termination statements necessary to terminate any financing or continuation
statements filed with respect to the Collateral. Such transfer shall be without
warranty by or recourse to the Trustee in its capacity as such, except as to the
absence of any liens on the Collateral created by or arising through the
Trustee, and shall be at the expense of the Grantor.

     Section 15.10. Survival of Representations and Covenants. All
representations, warranties and covenants of the Grantor contained herein shall
survive the execution and delivery of this Agreement and the termination of this
Agreement.

     Section 15.11. Waivers. The Grantor, to the fullest extent permitted by
applicable law, waives presentment and demand for payment of any of the
Obligations, protest and notice of dishonor or default with respect to any of
the Obligations, and all other notices to which the Grantor might otherwise be
entitled, except as otherwise expressly provided herein or in the Indenture.

     Section 15.12. Authority of the Trustee.

     (a)  The Trustee shall have and be entitled to exercise all powers
hereunder that are specifically granted to it by the terms hereof, together with
such powers as are reasonably incident thereto. The Trustee may perform any of
its duties hereunder or in connection with the Collateral by or through agents
or employees and shall be entitled to retain counsel and to act in reliance upon
the advice of counsel concerning all such matters. Except as otherwise expressly
provided in this Agreement or the Indenture, neither the Trustee nor any
director, officer, employee, attorney or agent of the Trustee shall be liable to
the Grantor for any action taken or omitted to be taken by the Trustee, in its
capacity as Trustee, hereunder, except for its own bad faith, gross negligence
or willful misconduct, and the Trustee shall not be responsible for the
validity, effectiveness or sufficiency hereof or of any document or security
furnished pursuant hereto. The Trustee and its directors, officers, employees,
attorneys and agents shall be entitled to rely on any communication, instrument
or document reasonably believed by it or them to be genuine and correct and to
have been signed or sent by the proper person or persons.

     (b)  The Grantor acknowledges that the rights and responsibilities of the
Trustee under this Agreement with respect to any action taken by the Trustee or
the exercise or non-exercise by the Trustee of any option, right, request,
judgment or other right or remedy provided for herein or resulting or arising
out of this Agreement shall, as between the Trustee and the Holders of the
Notes, be governed by the Indenture and by such other agreements with respect
thereto as may exist from time to time among them, but, as between the Trustee
and the Grantor, the Trustee shall be conclusively presumed to be acting as
agent for the Holders of the Notes with full and valid authority so to act or
refrain from acting, and the Grantor shall not be obligated or entitled to make
any inquiry respecting such authority.

     Section 15.13. Final Expression. This Agreement, together with the
Indenture and any other agreement executed in connection herewith, is intended
by the parties as a final expression of this Agreement and is intended as a
complete and exclusive statement of the terms and conditions thereof.

                                       -13-

<PAGE>

     Section 15.14. Rights of Holders of the Notes. No Holder of Notes shall
have any independent rights hereunder other than those rights granted to
individual Holders of the Notes pursuant to the Indenture; provided that nothing
in this subsection shall limit any rights granted to the Trustee under the Notes
or the Indenture.

     Section 15.15. Governing Law; Submission to Jurisdiction; Waiver of Jury
Trial; Waiver of Damages.

     (a)  THIS AGREEMENT SHALL BE GOVERNED BY AND INTERPRETED UNDER THE LAWS OF
THE STATE OF NEW YORK.

     (b)  ANYTHING CONTAINED IN THIS AGREEMENT OR IN ANY OTHER AGREEMENT BETWEEN
THE TRUSTEE AND THE PLEDGED SECURITIES INTERMEDIARY TO THE CONTRARY
NOTWITHSTANDING, THE "PLEDGED SECURITIES INTERMEDIARY'S JURISDICTION" WITH
RESPECT TO THE PLEDGED SECURITIES FOR PURPOSES OF SECTIONS 8-110(e), 9-305(a)(3)
AND 9-304(b)(1) OF THE UCC SHALL BE THE STATE OF NEW YORK.

     (c)  FOR ANY SUIT, ACTION OR PROCEEDING WITH RESPECT TO THIS AGREEMENT, THE
GRANTOR HEREBY AGREES TO SUBMIT TO THE JURISDICTION OF ANY FEDERAL OR STATE
COURT LOCATED IN THE CITY OF NEW YORK.

     (d)  THE GRANTOR AGREES THAT THE TRUSTEE SHALL, IN ITS CAPACITY AS TRUSTEE
OR IN THE NAME AND ON BEHALF OF ANY HOLDER OF NOTES, HAVE THE RIGHT, TO THE
FULLEST EXTENT PERMITTED BY APPLICABLE LAW (AND TO THE EXTENT THE TRUSTEE HAS
RECEIVED INDEMNITY DEEMED SATISFACTORY TO IT AND HAS AGREED TO DO SO), TO
PROCEED AGAINST THE GRANTOR OR THE COLLATERAL IN A COURT IN ANY LOCATION
REASONABLY SELECTED IN GOOD FAITH (AND HAVING PERSONAL OR IN REM JURISDICTION
OVER THE GRANTOR OR THE COLLATERAL, AS THE CASE MAY BE) TO ENABLE THE TRUSTEE TO
REALIZE ON SUCH COLLATERAL, OR TO ENFORCE A JUDGMENT OR OTHER COURT ORDER
ENTERED IN FAVOR OF THE TRUSTEE. THE GRANTOR AGREES, TO THE FULLEST EXTENT
PERMITTED BY APPLICABLE LAW, THAT IT WILL NOT ASSERT ANY COUNTERCLAIMS, SETOFFS
OR CROSSCLAIMS IN ANY PROCEEDING BROUGHT BY THE TRUSTEE TO REALIZE ON SUCH
PROPERTY OR TO ENFORCE A JUDGMENT OR OTHER COURT ORDER IN FAVOR OF THE TRUSTEE,
EXCEPT FOR SUCH COUNTERCLAIMS, SETOFFS OR CROSSCLAIMS WHICH, IF NOT ASSERTED IN
ANY SUCH PROCEEDING, COULD NOT OTHERWISE BE BROUGHT OR ASSERTED. THE GRANTOR
WAIVES, TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, ANY OBJECTION THAT IT
MAY HAVE TO THE LOCATION OF THE COURT IN THE CITY OF NEW YORK IN THE BOROUGH OF
MANHATTAN ONCE THE TRUSTEE HAS COMMENCED A PROCEEDING DESCRIBED IN THIS
PARAGRAPH INCLUDING, WITHOUT LIMITATION, ANY OBJECTION TO THE LAYING OF VENUE OR
BASED ON THE GROUNDS OF FORUM NON CONVENIENS.

     (e)  THE GRANTOR AGREES THAT EXCEPT AS OTHERWISE PROVIDED IN THIS AGREEMENT
OR THE INDENTURE, NEITHER THE TRUSTEE IN ITS CAPACITY AS TRUSTEE, OR Wilmington
Trust Company IN ITS CAPACITY AS PLEDGED SECURITIES INTERMEDIARY SHALL HAVE ANY
LIABILITY TO THE GRANTOR (WHETHER ARISING IN TORT, CONTRACT OR OTHERWISE) FOR
LOSSES SUFFERED BY THE GRANTOR IN CONNECTION WITH, ARISING OUT OF, OR IN ANY WAY
RELATED TO, THE TRANSACTIONS CONTEMPLATED AND THE RELATIONSHIP ESTABLISHED BY
THIS AGREEMENT, OR ANY ACT, OMISSION OR EVENT OCCURRING IN CONNECTION THEREWITH,
UNLESS SUCH LOSSES WERE THE RESULT OF ACTS OR OMISSIONS ON THE PART OF THE
TRUSTEE CONSTITUTING BAD FAITH, GROSS NEGLIGENCE OR WILLFUL MISCONDUCT.

                                       -14-

<PAGE>

     (f)  TO THE FULLEST EXTENT PERMITTED BY APPLICABLE LAW, THE GRANTOR WAIVES
THE POSTING OF ANY BOND OTHERWISE REQUIRED OF THE TRUSTEE OR ANY HOLDER OF NOTES
IN CONNECTION WITH ANY JUDICIAL PROCESS OR PROCEEDING TO ENFORCE ANY JUDGMENT OR
OTHER COURT ORDER PERTAINING TO THIS AGREEMENT OR ANY RELATED AGREEMENT OR
DOCUMENT ENTERED IN FAVOR OF THE TRUSTEE OR ANY HOLDER OF NOTES, OR TO ENFORCE
BY SPECIFIC PERFORMANCE, TEMPORARY RESTRAINING ORDER OR PRELIMINARY OR PERMANENT
INJUNCTION, THIS AGREEMENT OR ANY RELATED AGREEMENT OR DOCUMENT BETWEEN THE
GRANTOR ON THE ONE HAND AND THE TRUSTEE AND/OR THE HOLDERS OF THE NOTES ON THE
OTHER HAND.

                                       -15-

<PAGE>

     IN WITNESS WHEREOF, the Grantor, the Trustee and the Pledged Securities
Intermediary have each caused this Agreement to be duly executed and delivered
as of the date first above written.

                                          Grantor:

                                          MEDAREX, INC.


                                          By: __________________________________
                                              Name:
                                              Title:


                                          Trustee:

                                          WILMINGTON TRUST COMPANY


                                          By: __________________________________
                                              Name:
                                              Title:


                                          Pledged Securities Intermediary:

                                          WILMINGTON TRUST COMPANY

                                          By: __________________________________
                                              Name:
                                              Title:

                                       -16-

<PAGE>

                                                                      SCHEDULE I

                               PLEDGED SECURITIES


                                                           PRINCIPAL
SECURITY                  CUSIP NO.      MATURITY           AMOUNT
----------------------   -----------   ------------   -----------------

STRIPS CPN 02/15/04       912833CK4       2/15/04        $ 2,965,498.80
STRIPS CPN 08/15/04       912833CL2       8/15/04        $ 2,626,444.50
STRIPS CPN 02/15/05       912833CM0       2/15/05        $ 2,608,376.90
STRIPS CPN 08/15/05       912833CN8       8/15/05        $ 2,575,297.25
STRIPS CPN 02/15/06       912833CP3       2/15/06        $ 2,529,862.55
STRIPS CPN 08/15/06       912833CQ1       8/15/06        $ 2,488,811.90
                                                      -----------------
     TOTAL                                               $15,794,291.90
                                                      =================