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                                  Exhibit 10. 1

                      Medarex, Inc. 2001 Stock Option Plan

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                                  MEDAREX, INC.
                             2001 STOCK OPTION PLAN

     Section 1. Purpose of the Plan. The purpose of the 2001 Stock Option Plan
(the "Plan") is to aid Medarex, Inc. (the "Corporation") and its subsidiaries in
securing and retaining directors, consultants, officers and other key employees
of outstanding ability and to motivate such employees to exert their best
efforts on behalf of the Corporation and its subsidiaries. In addition, the
Corporation expects that it will benefit from the added interest which the
respective optionees and participants will have in the welfare of the
Corporation as a result of their ownership or increased ownership of the Common
Stock of the Corporation (the "Stock").

     Section 2. Administration. (a) the Board of Directors of the Corporation
(the "Board") shall designate a Committee of not less that two (2) Directors
(the "Committee") who shall serve at the pleasure of the Board. Each member of
the Committee shall be a "non-employee" director within the meaning of Rule
16b-3(b) (3)(i) under the Securities Exchange Act of 1934, as amended (the
"Exchange Act"), as such Rule or any other comparable rule may be in effect from
time to time, while serving on the Committee. The Board shall fill any vacancies
on the Committee and may remove any member of the Committee at any time with or
without cause. The Committee shall select its chairman and hold its meetings at
such times and places as it may determine. A majority of the whole Committee
present at a meeting at which a quorum is present, or an act approved in writing
by all members of the Committee, shall be an act of the Committee. The Committee
shall have full power and authority, subject to such resolutions not
inconsistent with the provisions of the Plan as may from time to time be issued
or adopted by the Board (provided the entire Board acting on the matter are
Disinterested Persons), to grant to Eligible Persons (as defined herein)
pursuant to the provisions of the Plan (i) stock options to purchase shares,
(ii) stock appreciation rights, (iii) restricted stock, (iv) deferred stock, or
(v) other Stock-based awards permitted hereunder (each of the foregoing being an
"AWARD" and collectively, the "AWARDS"). The Committee shall also interpret the
provisions of the Plan and any AWARD issued under the Plan (and any agreements
relating thereto) and supervise the administration of the Plan.

          (b) The Committee shall: (i) select the directors, consultants,
officers and other key employees of the Corporation and its subsidiaries to whom
AWARDS may from time to time be granted hereunder; (ii) determine whether
incentive stock options (under Section 422 of the Internal Revenue Code of 1986,
as the same may be amended from time to time, hereinafter referred to as the
"Code"), nonqualified stock options, stock appreciation rights, restricted
stock, deferred stock, or other Stock-based awards, or a combination of the
foregoing, are to be granted hereunder; (iii) determine the number of shares to
be covered by each AWARD granted hereunder; (iv) determine the terms and
conditions, not inconsistent with the provisions of the Plan, of any AWARD
granted hereunder (including but not limited to any restriction and forfeiture
condition on such AWARD and/or the shares of Stock relating thereto); (v)
determine whether, to what extent and under what circumstances AWARDS may be
settled in cash; (vi) determine whether, to what extent, and under what
circumstances Stock and other amounts payable with respect to an AWARD under
this Plan shall be deferred either automatically or at the election of the


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participant; and (vii) determine whether, to what extent, and under what
circumstances option grants and/or other AWARDS under the Plan are to be made,
and operate, on a tandem basis.

          (c) All decisions made by the Committee pursuant to the provisions of
the Plan and related orders or resolutions of the Board (as and to the extent
permitted hereunder) shall be final, conclusive and binding on all persons,
including the Corporation, its shareholders, employees and Plan participants.

          (d) No member of the Committee shall be liable for any action or
determination made in good faith with respect to the Plan or any AWARD
thereunder.

     Section 3. Stock Subject to the Plan. Except as otherwise provided by this
Section 3, the total number of shares of Stock available for distribution under
the Plan is 3,500,000. The total number of shares of stock with respect to which
AWARDS may be granted to any participant in any year is 400,000 shares. Such
shares may consist, in whole or in part, of authorized and unissued shares or
treasury shares, except that treasury shares must be used in the case of
restricted stock. If any shares that have been optioned cease to be subject to
option because the option has expired or has been deemed to have expired or has
been surrendered pursuant to the Plan, or if any shares of restricted stock are
forfeited or such AWARD otherwise terminates without the actual or deemed
delivery of such shares, such shares shall again be subject to an AWARD under
the Plan.

     In the event of any merger, reorganization, consolidation,
recapitalization, stock dividend, extraordinary cash dividend, or other change
in corporate structure affecting the Stock, such adjustment shall be made in the
aggregate number of shares which may be delivered under the Plan, in the number
and/or option price of shares subject to outstanding options granted under the
Plan, and/or in the number of shares subject to restricted stock, deferred
stock, or other Stock-based awards granted under the Plan as may be determined
to be appropriate by the Committee, in its sole discretion; provided that the
number of shares subject to any AWARDS shall always be a whole number; and
provided further that, with respect to incentive stock options, no such
adjustment shall be authorized to the extent that such adjustment would
constitute a modification as defined in Section 424(h)(3) of the Code or cause
the Plan to violate Section 422(b)(1) of the Code or any successor provision
thereto. Such adjusted option price shall also be used to determine the amount
payable by the Corporation upon the exercise of any stock appreciation right
associated with any option. In addition, subject to the limitations provided in
Section 11, the Committee is authorized to make adjustments in the terms and
conditions of, and performance criteria relating to, AWARDS in recognition of
unusual or nonrecurring events (including, without limitation, events described
in this paragraph) affecting the Corporation or the financial statements of the
Corporation, or in response to changes in applicable laws, regulations or
accounting principles.

     Section 4. Eligibility. Directors, consultants, officers and other key
employees of the Corporation and its subsidiaries who are responsible for the
management, growth, profitability and protection of the business of the
Corporation and its subsidiaries are eligible to be granted AWARDS under the
Plan (each an "Eligible Person" and collectively "Eligible Persons"). The
participants under the Plan shall be selected from time to time by the
Committee, in its sole discretion, from among those eligible, and the Committee
shall determine, in its sole discretion, the number of shares covered by each


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stock option, the number of stock appreciation rights (if any) granted to each
optionee, and the number of shares (if any) subject to restricted stock,
deferred stock or other Stock-based awards granted to each participant.

     For purposes of the Plan, a subsidiary of the Corporation shall be any
corporation which at the time qualifies as a subsidiary thereof under the
definition of "subsidiary corporation" in Section 424(f) of the Code.

     Section 5. Stock Options. Any stock option granted under the Plan shall be
in such form as the Committee may from time to time approve. Any such option
shall be subject to the following terms and conditions and shall contain such
additional terms and conditions, not inconsistent with the provisions of the
Plan, as the Committee shall deem desirable.

          (a) Option Price. The purchase price per share of the Stock
purchasable under a stock option shall be determined by the Committee, but will
be not less than 100% of the fair market value of the Stock on the date of the
grant of the option, as determined in accordance with procedures established by
the Committee. Notwithstanding the foregoing, the purchase price per share of
the Stock purchasable under any incentive stock option granted to any person who
is the beneficial owner of more than 10% of the Corporation's issued and
outstanding Stock (a "10% owner") shall not be less then 110% of the fair market
value of the Stock on the date of the grant of the option, as determined in
accordance with procedures established by the Committee.

          (b) Option Period. The term of each stock option shall be fixed by the
Committee, but no incentive stock option shall be exercisable after the
expiration of 10 years from the date the option is granted. Notwithstanding the
foregoing, no incentive stock option granted to a 10% owner shall be exercisable
after the expiration of five years from the date the option is granted.

          (c) Exercisability. (1) Stock options shall be exercisable at such
time or times as determined by the Committee at or subsequent to the date of
grant. Unless otherwise determined by the Committee at or subsequent to the date
of grant, no stock option shall be exercisable until the first anniversary date
of the granting of the option, except as provided in paragraphs (f), (g) or (h)
of this Section 5; provided, however, that notwithstanding the foregoing from
and after a Change of Control (as hereinafter defined) all stock options shall
become immediately exercisable to the full extent of the AWARD.

               (2) Solely for Federal income tax purposes, to the extent that
the aggregate fair market value of Stock with respect to which incentive stock
options are exercisable for the first time by a participant during any calendar
year exceeds $100,000.00 (as of the date of grant), such options shall be
treated as options which are not incentive stock options. For purposes of this
rule, options shall be taken into account in the order in which they were
granted.

               (3) As used herein, "Change of Control" shall mean any of the
following events:


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          (A) An acquisition (other than directly from the Corporation) of any
voting securities of the Corporation (the "Voting Securities") by any "Person"
(as the term "person" is used for purposes of Section 13(d) or 14(d) of the
Exchange Act) immediately after which such Person has "Beneficial Ownership"
(within the meaning of Rule 13d-3 promulgated under the Exchange Act) of 15% or
more of the combined voting power of the Corporation's then outstanding Voting
Securities; provided, however, that in determining whether a Change of Control
has occurred, voting securities which are acquired in a "Non-Control
Acquisition" (as hereinafter defined) shall not constitute an acquisition which
would cause a Change of Control.

          A "Non-Control Acquisition" shall mean an acquisition by (i) an
employee benefit plan (or a trust forming a part thereof) maintained by (x) the
Corporation or (y) any corporation or other Person of which a majority of its
voting power or its equity securities or equity interest is owned directly or
indirectly by the Corporation (a "Subsidiary"), (ii) the Corporation or any
Subsidiary, or (iii) any Person in connection with a Non-Control Transaction (as
defined below);

          (B) The individuals who, as of April 30, 1991 were members of the
Board (the "Incumbent Board"), cease for any reason to constitute at least 66
2/3% of the Board; provided, however, that if the election, or nomination for
election by the Corporation's stockholders, of any new director was approved by
a vote of at least 66 2/3% of the Incumbent Board, such new director shall be
considered as a member of the Incumbent Board; provided, further, however, that
no individual shall be considered a member of the Incumbent Board if such
individual initially assumed office as a result of either an actual or
threatened "Election Contest" (as described in Rule 14a-11 promulgated under the
Exchange Act) or other actual or threatened solicitation of proxies or consents
by or on behalf of a Person other than the Board (a "Proxy Contest") including
by reason of any agreement intended to avoid or settle any Election Contest or
Proxy Contest; or

          (C) Approval of the Corporation's shareholders of: (1) a merger,
consolidation or reorganization involving the Corporation, unless (i) the
stockholders of the Corporation, immediately before such merger, consolidation
or reorganization, own, directly or indirectly immediately following such
merger, consolidation or reorganization, at least 66 2/3% of the combined voting
power of the outstanding Voting Securities of the Corporation resulting from
such merger or consolidation or reorganization (the "Surviving Corporation") in
substantially the same proportion as their ownership of the Voting Securities
immediately before such merger, consolidation or reorganization, (ii) the
individuals who were members of the Incumbent Board immediately prior to the
execution of the agreement providing for such merger, consolidation or
reorganization constitute at least 66 2/3% of the members of the board of
directors of the Surviving Corporation, and (iii) no Person, other than the
Corporation, any Subsidiary, any employee benefit plan (or any trust forming a
part thereof) maintained by the Corporation, the Surviving Corporation or any
Subsidiary, or any Person who, immediately prior to such merger, consolidation
or reorganization had Beneficial Ownership of 15% or more of the then
outstanding Voting Securities of the Corporation, has Beneficial Ownership of
15% or more of the combined voting power of the Surviving Corporation's then
outstanding voting securities (a transaction described in clause (i) through
(iii) shall herein be referred to as a "Non-Control Transaction"); (2) a
complete liquidation or dissolution of the Corporation; or (3) an agreement for
the sale or


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     other disposition of all or substantially all of the assets of the
     Corporation to any Person (other than a transfer to a Subsidiary).

          Notwithstanding the foregoing, a Change of Control shall not be deemed
     to occur solely because any Person (the "Subject Person") acquired
     Beneficial Ownership of more than the permitted amount of the outstanding
     Voting Securities as a result of the acquisition of Voting Securities by
     the Corporation which, by reducing the number of Voting Securities
     outstanding, increases the proportional number of shares Beneficially Owned
     by the Subject Person, provided that if a Change of Control would occur
     (but for the operation of this sentence) as a result of the acquisition of
     Voting Securities by the Corporation, and after such share acquisition, the
     Subject Person becomes the Beneficial Owner of any additional Voting
     Securities which increases the percentage of the then outstanding Voting
     Securities Beneficially Owned by the Subject Person, then a Change of
     Control shall occur.

          (d) Method of Exercise. Stock options may be exercised, in whole or in
part, by giving written notice of exercise to the Corporation specifying the
number of shares to be purchased. Such notice shall be accompanied by payment in
full of the purchase price in cash, either by certified or bank check; provided,
however, that after a Change of Control (x) an optionee (other than an optionee
who initiated a Change of Control in a capacity other than as an officer or
director of the Corporation) who is an officer or director of the Corporation
(within the meaning of Section 16 of the Exchange Act and the rules and
regulations promulgated thereunder), during the 60-day period after six (6)
months after a Change of Control, with respect to an option that is
unaccompanied by a stock appreciation right and (y) any other optionee, during
the 60-day period from and after a Change of Control, who at the time of
exercise is not an officer or director with respect to an option that is
unaccompanied by a stock appreciation right shall, unless the Committee shall
determine otherwise at the time of grant, have the right, in lieu of the payment
of the full purchase price of the shares of the Stock being purchased under the
stock option and by giving written notice to the Corporation, to elect (within
such respective periods) to surrender all or part of the stock option to the
Corporation and to receive in cash an amount equal to the amount by which the
fair market value per share of the Stock on the date of exercise shall exceed
the purchase price per share under the stock option multiplied by the number of
shares of the Stock granted under the stock option as to which the right granted
by this proviso shall have been exercised. However, any officer, director or 10%
owner (collectively, "Insider") may only settle the right granted by this
proviso pursuant to an irrevocable election to settle the right no earlier than
six (6) months after the date of such election, provided that the transaction
                                                --------
giving rise to the award of the right is approved by the Company's shareholders
(excluding Insider shareholders).

          The written notice provided by the optionee shall specify the
optionee's election to purchase shares subject to the stock option or to receive
the cash payment herein provided.

          Notwithstanding the foregoing, the Committee may, in its sole
discretion, authorize payment in whole or in part of the purchase price to be
made in unrestricted stock already owned by the optionee, or, in the case of the
nonqualified stock option, in restricted stock, or deferred stock subject to an
AWARD hereunder (based upon the fair market value of the Stock on the date the
option is exercised as determined by the Committee). The Committee may authorize
such payment at or after grant, except


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that in the case of an incentive stock option, any right to make payment in
unrestricted stock already owned must be included in the option at the time of
grant. No shares of Stock shall be issued until full payment therefor has been
made. Subject to paragraph (i) of this Section 5, an optionee shall have the
rights to dividends or other rights of a stockholder with respect to shares
subject to the option when the optionee has given written notice of exercise,
has paid in full for such shares, and, if requested, has given the
representation described in paragraph (a) of Section 14.

          As used in this paragraph (d) of Section 5, the fair market value of
the Stock on the date of exercise shall mean:

               (i) with respect to an election by an optionee to receive cash in
          respect of a stock option which is not an incentive stock option, the
          "Change of Control Fair Market Value", as defined below; and

               (ii) with respect to an election by an optionee to receive cash
          in respect of a stock option which is an incentive stock option, the
          fair market value of the Stock on the date of exercise, determined in
          the same manner as the fair market value of the Stock on the date of
          grant of a stock option is determined pursuant to paragraph (a) of
          Section 5 of the Plan.

          (e) Restrictions on Transferability. The Committee, in its sole
discretion, may impose such restrictions on the transferability of stock options
granted hereunder as it deems appropriate. Any such restrictions shall be set
forth in the stock option agreement with respect to such stock options.
Incentive stock options may not be transferred by an optionee other than by will
or by the laws of descent and distribution.

          (f) Termination by Death. Except to the extent otherwise provided by
the Committee at or after the time of grant, if an optionee's relationship with
or employment by the Corporation and/or any of its subsidiaries terminates by
reason of death, the stock option may thereafter be immediately exercised in
full by the legal representative of the estate or by the legatee of the optionee
under the will of the optionee, for a period of 15 months from the date of such
death or until the expiration of the stated period of the option whichever
period is the shorter.

          (g) Termination by Reason of Retirement or Permanent Disability.
Except to the extent otherwise provided by the Committee at or after the time of
grant, if an optionee's relationship with or employment by the Corporation
and/or any of its subsidiaries terminates by reason of retirement or permanent
disability, any stock option held by such optionee may thereafter be exercised
in full, but may not be exercised after three years from the date of such
termination or the expiration of the stated period of the option, whichever
period is the shorter; provided, however, that if the optionee dies within such
three-year period, any unexercised stock option held by such optionee shall
thereafter be exercisable to the extent to which it was exercisable at the time
of death for a period of 12 months from the date of the optionee's death or for
the stated period of the option, whichever period is the shorter.


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          (h) Other Termination. Unless otherwise determined by the Committee at
or after grant, if an optionee's relationship with or employment by the
Corporation terminates for any reason other than death, permanent disability or
retirement, the stock option shall thereupon terminate; provided, however, that
if such termination is by action of the Corporation and other than discharge for
reason of willful violation of the rules of the Corporation or by voluntary
resignation of the optionee, in either case within 18 months following a Change
of Control, any stock options held by the optionee may be exercised by the
optionee until the earlier of six months and one day after such termination or
the expiration of such options in accordance with their terms.

          (i) Option Buyout. The Committee may at any time offer to repurchase
an option (other than an option which has been held for less than six months by
an Insider) based on such terms and conditions as the Committee shall establish
and communicate to the optionee at the time that such offer is made.

          (j) Form of Settlement. In its sole discretion, the Committee may
provide, at the time of grant, that the shares to be issued upon an option's
exercise shall be in the form of restricted stock or deferred stock, or may
reserve other than with respect to incentive stock options the right to so
provide after the time of grant.

     Section 6. Stock Appreciation Rights. (a) Grant and Exercise. Stock
appreciation rights may be granted in conjunction with (or in accordance with
Section 9, separated from) all or part of any stock option granted under the
Plan, as follows: (i) in the case of a nonqualified stock option, such rights
may be granted either at the time of the grant of such option or at any
subsequent time during the term of the option; and (ii) in the case of an
incentive stock option, such rights may be granted only at the time of the grant
of the option. A "stock appreciation right" is a right to receive cash or Stock,
as provided in this Section 6, in lieu of the purchase of a share under a
related option. A stock appreciation right, or applicable portion thereof, shall
terminate and no longer be exercisable upon the termination or exercise of the
related stock option, except that a stock appreciation right granted with
respect to less than the full number of shares covered by a related stock option
shall not be reduced until the exercise or termination of the related stock
option exceeds the number of shares not covered by the stock appreciation right.
A stock appreciation right may be exercised by an optionee, in accordance with
paragraph (b) of this Section 6, by surrendering the applicable portion of the
related stock option. Upon such exercise and surrender, the optionee shall be
entitled to receive an amount determined in the manner prescribed in paragraph
(b) of this Section 6. Options which have been so surrendered, in whole or in
part, shall no longer be exercisable to the extent the related stock
appreciation rights have been exercised.

          (b) Terms and Conditions. Stock appreciation rights shall be subject
to such terms and conditions, not inconsistent with the provisions of the Plan,
as shall be determined from time to time by the Committee, including the
following:

               (i) Stock appreciation rights shall be exercisable only at such
          time or times and to the extent that the stock options to which they
          relate shall be exercisable. Except as otherwise provided in Section
          5, an Insider (as previously defined in Section 5) may only settle a
          stock appreciation right by satisfying either of the following
          conditions:

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                    (A) the stock appreciation right is settled at least six (6)
          months after its date of grant; or else

                    (B) the settlement of the stock appreciation right is made
          pursuant to an irrevocable election to settle the right no earlier
          than six (6) months after the date of such election.

                    None of the conditions of this Section 6(b)(i) shall be
          applicable in the event of death or permanent disability of the
          optionee.

               (ii) Upon the exercise of a stock appreciation right, an optionee
          shall be entitled to receive up to, but no more than, an amount in
          cash or whole shares of the Stock as determined by the Committee in
          its sole discretion equal to the excess of the fair market value of
          one share of Stock over the option price per share specified in the
          related stock option multiplied by the number of shares in respect of
          which the stock appreciation right shall have been exercised;
          provided, however, that the payment in settlement of stock
          appreciation rights during the period from and after a Change of
          Control shall be entirely in cash. Each stock appreciation right may
          be exercised only at the time and so long as a related option, if any,
          would be exercisable or as otherwise permitted by applicable law;
          provided however, that no stock appreciation right granted under the
          Plan to an Insider then subject to Section 16 of the Exchange Act
          shall be exercised during the first six months of its term. The fair
          market value of the Stock on the date of exercise of a stock
          appreciation right shall be determined in the same manner as the fair
          market value of the Stock on the date of grant of a stock option is
          determined pursuant to paragraph (a) of Section 5 of the Plan;
          provided, however, that during the 60-day period from and after a
          Change of Control, the fair market value of the Stock on the date of
          exercise shall mean, with respect to the exercise of a stock
          appreciation right accompanying an option which is not an incentive
          stock option, the "Change of Control Fair Market Value."

               For purposes of this Plan, the "Change of Control Fair Market
          Value" shall mean the higher of (x) the highest reported sale price,
          regular way, of a share of the Stock on the Composite Tape for New
          York Stock Exchange Listed Stock during the 60-day period prior to the
          date of the Change of Control or, if such security is not listed or
          admitted to trading on the New York Stock Exchange, on the principal
          national securities exchange on which such security is listed or
          admitted to trading or, if not listed or admitted to trading on any
          national securities exchange, on the Nasdaq National Market or, if
          such security is not quoted on such Nasdaq National Market, the
          average of the closing bid and asked prices during such 60-day period
          in the over-the-counter market as reported by the National Association
          of Securities Dealers Automated Quotation ("NASDAQ") system or, if bid
          and asked prices for such security during such period shall not have
          been reported through NASDAQ, the average of the bid and asked prices
          for such period as furnished by any New York Stock Exchange member
          firm regularly making a market in such security selected for such
          purpose by the Board of Directors of the Corporation or a committee
          thereof or, if such security is not publicly traded, the fair market
          value thereof as

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          determined by an independent investment banking or appraisal firm
          experienced in the valuation of such securities selected in good faith
          by the Board of Directors of the Corporation or a committee thereof
          or, if no such investment banking or appraisal firm is in the good
          faith judgment of the Board of Directors or such committee available
          to make such determination, as determined in good faith by the Board
          of Directors of the Corporation or such committee and (y) if the
          Change of Control is the result of a transaction or series of
          transactions described in paragraph (i) or (iii) of the definition of
          Change of Control set forth in Section 5(c), the highest price per
          share of the Stock paid in such transaction or series of transactions
          (in the case of a Change of Control described in such paragraph (i) of
          Section 5(c), as reflected in any Schedule 13D filed by the person
          having made the acquisition).

               (iii) The Committee, in its sole discretion, may impose such
          restrictions on the transferability of stock appreciation rights as it
          deems appropriate. Any such restrictions shall be set forth in the
          written agreement between the Corporation and the optionee with
          respect to such rights.

               (iv) Upon the exercise of a stock appreciation right, the stock
          option or part thereof to which such stock appreciation right is
          related shall be deemed to have been exercised for the purpose of the
          limitation of the number of shares of the Stock to be issued under the
          Plan, as set forth in Section 3 of the Plan.

               (v) Stock appreciation rights granted in connection with
          incentive stock options may be exercised only when the market price of
          the Stock subject to the incentive stock option exceeds the option
          price of the incentive stock option.

     Section 7. Restricted Stock. (a) Stock and Administration. Shares of
restricted stock may be issued either alone or in addition to stock options,
stock appreciation rights, deferred stock or other Stock-based awards granted
under the Plan. The Committee shall determine the directors, consultants,
officers and key employees of the Corporation and its subsidiaries to whom, and
the time or times at which, grants of restricted stock will be made, the number
of shares to be awarded, the time or times within which such AWARDS may be
subject to forfeiture, and all other conditions of the AWARDS. The provisions of
restricted stock AWARDS need not be the same with respect to each recipient.

          (b) Awards and Certificates. The prospective recipient of an AWARD of
shares of restricted stock shall not, with respect to such AWARD, be deemed to
have become a participant, or to have any rights with respect to such AWARD,
until and unless such recipient shall have executed an agreement or other
instrument evidencing the AWARD and delivered a fully executed copy thereof to
the Corporation and otherwise complied with the then applicable terms and
conditions.

               (i) Each participant shall be issued a stock certificate in
          respect of shares of restricted stock awarded under the Plan. Such
          certificate shall be registered in the name of the participant, and
          shall bear an appropriate legend referring to the terms, conditions,
          and restrictions applicable to such AWARD, substantially in the
          following form:

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               "The transferability of this certificate and the shares of stock
          represented hereby are subject to the terms and conditions (including
          forfeiture) of the Medarex, Inc. 2001 Stock Option Plan and an
          Agreement entered into between the registered owner and Medarex, Inc.
          Copies of such Plan and Agreement are on file in the offices of
          Medarex, Inc., 707 State Road, Suite 206, Princeton, New Jersey
          08540."

               (ii) The Committee shall require that the stock certificates
          evidencing such shares be held in custody by the Corporation until the
          restrictions thereon shall have lapsed, and shall require, as a
          condition of any restricted stock AWARD, that the participant shall
          have delivered a stock power, endorsed in blank, relating to the Stock
          covered by such AWARD.

          (c)  Restrictions and Conditions. The shares of restricted stock
awarded pursuant to the Plan shall be subject to the following restrictions and
conditions:

                 (i) subject to the provisions of this Plan during a period
          set by the Committee commencing with the date of such AWARD (the
          "restriction period"), the participant shall not be permitted to sell,
          transfer, pledge, or assign shares of restricted stock awarded under
          the Plan. Within these limits the Committee may provide for the
          lapse of such restrictions in installments where deemed appropriate.

               (ii)  Except as provided in paragraph (c) of this Section 7, the
          participants shall have, with respect to the shares of restricted
          stock, all of the rights of a stockholder of the Corporation,
          including the right to vote the restricted stock and the right to
          receive any cash dividends. The Committee, in its sole discretion, may
          permit or require the payment of cash dividends to be deferred and, if
          the Committee so determines, reinvested in additional restricted stock
          or otherwise reinvested. Certificates for shares of unrestricted stock
          shall be delivered to the participant promptly after, and only after,
          the period of forfeiture shall expire without forfeiture in respect of
          such shares of restricted stock.

               (iii) Subject to the provisions of paragraph (c)(iv) of this
          Section 7, upon termination of employment of any reason during the
          restriction period, all shares still subject to restriction shall be
          forfeited by the participant and reacquired by the Corporation.

               (iv)  In the event of a participant's retirement, permanent
          disability, or death, or in cases of special circumstances, the
          Committee may, in its sole discretion, when it finds that a waiver
          would be in the best interests of the Corporation, waive in whole or
          in part any or all remaining restrictions with respect to such
          participant's shares of restricted stock.

               (v)   Notwithstanding anything in the foregoing to the contrary,
          upon a Change of Control any and all restrictions on restricted stock
          shall lapse regardless of the restriction period established by the
          Committee and all such restricted stock shall become fully vested and
          nonforfeitable.


                                       -10-

<PAGE>

     Section 8. Deferred Stock Awards. (a) Stock and Administration. AWARDS of
the right to receive Stock that is not to be distributed to the participant
until after a specified deferral period (such AWARD and the deferred stock
delivered thereunder hereinafter as the context shall require, referred to as
the "deferred stock") may be made either alone or in addition to stock options,
stock appreciation rights, or restricted stock, or other Stock-based awards
granted under the Plan. The Committee shall determine the directors,
consultants, officers and key employees of the Corporation and its subsidiaries
to whom and the time or times at which deferred stock shall be awarded, the
number of shares of deferred stock to be awarded to any participant, the
duration of the period (the "Deferral Period") during which, and the conditions
under which, receipt of the Stock will be deferred, and the terms and conditions
of the AWARD in addition to those contained in paragraph (b) of this Section 8.
In its sole discretion, the Committee may provide for a minimum payment at the
end of the applicable Deferral Period based on a stated percentage of the fair
market value on the date of grant of the number of shares covered by a deferred
stock AWARD. The Committee may also provide for the grant of deferred stock upon
the completion of a specified performance period. The provisions of deferred
stock AWARDS need not be the same with respect to each recipient.

          (b)  Terms and Conditions. Deferred stock AWARDS made pursuant to this
Section 8 shall be subject to the following terms and conditions:

               (i)   Subject to the provisions of the Plan, the shares to be
          issued pursuant to a deferred stock AWARD may not be sold, assigned,
          transferred, pledged or otherwise encumbered during the Deferral
          Period or Elective Deferral Period (defined below), where applicable,
          and may be subject to a risk of forfeiture during all or such portion
          of the Deferral Period as shall be specified by the Committee. At the
          expiration of the Deferral Period and Elective Deferral Period, share
          certificates shall be delivered to the participant, or the
          participant's legal representative, in a number equal to the number of
          shares covered by the deferred stock AWARD.

               (ii)  Amounts equal to any dividends declared during the Deferral
          Period with respect to the number of shares covered by a deferred
          stock AWARD will be paid to the participant currently, or deferred and
          deemed to be reinvested in additional deferred stock or otherwise
          reinvested, as determined at the time of the AWARD by the Committee,
          in its sole discretion.

               (iii) Subject to the provisions of paragraph (b)(iv) of this
          Section 8, upon termination of the relationship with or employment by
          the Corporation for any reason during the Deferral Period for a given
          deferred stock AWARD, the deferred stock in question shall be
          forfeited by the participant.

               (iv)  In the event of the participant's retirement, permanent
          disability or death during the Deferral Period (or Elective Deferral
          Period, where applicable), or in cases of special circumstances, the
          Committee may, in its sole discretion, when it finds that a waiver
          would be in the best interests of the Corporation, waive in whole or
          in part any or all of the remaining deferral limitations imposed
          hereunder with respect to any or all of the


                                       -11-

<PAGE>

          participant's deferred stock. Anything in the Plan to the contrary
          notwithstanding, upon the occurrence of a Change of Control, the
          Deferral Period and the Elective Deferral Period with respect to each
          deferred stock AWARD shall expire immediately and all share
          certificates relating to such deferred stock AWARDS shall be delivered
          to each participant or the participant's legal representative.

               (v) Prior to completion of the Deferral Period, a participant may
          elect to defer further the receipt of the deferred stock AWARD for a
          specified period or until a specified event (the "Elective Deferred
          Period"), subject in each case to the approval of the Committee and
          under such terms as are determined by the Committee, all in its sole
          discretion.

               (vi) Each deferred stock AWARD shall be confirmed by a deferred
          stock agreement or other instrument executed by the Committee and by
          the participant.

     Section 9. Other Stock-Based Awards. (a) Stock and Administration. Other
AWARDS of the Stock and other AWARDS that are valued in whole or in part by
reference to, or are otherwise based on the Stock ("Other Stock-based AWARDS"),
including (without limitation) performance shares and convertible debentures,
may be granted either alone or in addition to other AWARDS granted under the
Plan. Subject to the provisions of the Plan, the Committee shall have sole and
complete authority to determine the directors, consultants, officers and key
employees of the Corporation and/or any of its subsidiaries to whom and the time
or times at which such Other Stock-based AWARDS shall be made, the number of
shares of the Stock to be awarded pursuant to such Other Stock-based AWARDS and
all other conditions of the Other Stock-based AWARDS. The Committee may also
provide for the grant of the Stock upon the completion of a specified
performance period. The provisions of Other Stock-based AWARDS need not be the
same with respect to each recipient.

          (b) Terms and Conditions. Other Stock-based AWARDS made pursuant to
this Section 9 shall be subject to the following terms and conditions:

               (i)  Subject to the provisions of this Plan, shares or interests
          in shares subject to Other Stock-based AWARDS made under this Section
          9 may not be sold, assigned, transferred, pledged or otherwise
          encumbered prior to the date on which the shares are issued, or, if
          later, the date on which any applicable restriction, performance or
          deferral period lapses.

               (ii) Subject to the provisions of this Plan and the Other
          Stock-based AWARD agreement, the recipients of Other Stock-based
          AWARDS under this Section 9 shall be entitled to receive, currently or
          on a deferred basis, interest or dividends or interest or dividend
          equivalents with respect to the number of shares or interests therein
          covered by the Other Stock-based AWARDS, as determined at the time of
          the Other Stock-based AWARDS by the Committee, in its sole discretion,
          and the Committee may provide that such amounts (if any) shall be
          deemed to have been reinvested in additional Stock or otherwise
          reinvested.


                                       -12-

<PAGE>

               (iii)  Any Other Stock-based AWARDS under this Section 9 and any
          Stock covered by any such Other Stock-based AWARD may be forfeited to
          the extent so provided in the Other Stock-based AWARD agreement, as
          determined by the Committee, in its sole discretion.

               (iv)   In the event of the participant's retirement, permanent
          disability or death, or in cases of special circumstances, the
          Committee may, in its sole discretion, when it finds that a waiver
          would be in the best interests of the Corporation, waive in whole or
          in part any or all of the remaining limitations imposed hereunder (if
          any) with respect to any or all Other Stock-based AWARDS under this
          Section 9. Anything in the Plan to the contrary notwithstanding, any
          limitations imposed with respect to any Other Stock-based AWARD under
          this Section 9, including any provision providing for the forfeiture
          of any Other Stock-based AWARD under any circumstance, shall terminate
          immediately upon a Change of Control and the number of shares of or
          interests in the Stock subject to such Other Stock-based AWARD shall
          be delivered to the participant (or, in the case of an Other
          Stock-based AWARD with respect to which such number is not
          determinable, such number of shares of or interests in the Stock as is
          determined by the Committee and set forth in the terms of such Other
          Stock-based AWARD).

               (v)    Each Other Stock-based AWARD under this Section 9 shall be
          confirmed by an agreement or other instrument executed by the
          Corporation and by the participant.

               (vi)   The Stock or interests therein (including securities
          convertible into the Stock) paid or awarded on a bonus basis under
          this Section 9 shall be issued for no cash consideration; the Stock or
          interests therein (including securities convertible into the Stock)
          purchased pursuant to a purchase right awarded under this Section 9
          shall be priced at least 50% of the fair market value of the Stock on
          the date of grant.

               (vii)  The Committee, in its sole discretion, may impose such
          restrictions on the transferability of Other Stock-based Awards as it
          deems appropriate. Any such restrictions shall be set forth in the
          written agreement between the Corporation and the optionee with
          respect to such Award.

               (viii) Each Other Stock-based AWARD to an Insider under this
          Section 9 shall be subject to all of the limitations and
          qualifications that may be required by Section 16 of the Exchange Act
          and all of the rules and regulations promulgated thereunder.

     Section 10. Transfer, Leave of Absence, etc. For purposes of the Plan: (a)
a transfer of an employee from the Corporation to a subsidiary, or vice versa,
or from one subsidiary to another; (b) a leave of absence, duly authorized in
writing by the Corporation, for military service or sickness, or for any other
purposes approved by the Corporation if the period of such leave does not exceed
90 days; and (c) a leave of absence in excess of 90 days, duly authorized in
writing by the Corporation, shall not be deemed a termination of employment.


                                       -13-

<PAGE>

     Section 11. Amendments and Termination. The Board may amend, alter, or
discontinue the Plan, but no amendment, alteration, or discontinuation shall be
made which would impair the rights of an optionee or participant under any AWARD
theretofore granted, without the optionee's or participant's consent, or which
without the approval of the shareholders would:

          (a) except as is provided in Section 3 of the Plan, increase the total
     number of shares available for the purpose of the Plan;

          (b) subsequent to the date of grant decrease the option price of any
     stock option to less than 100% (110% in the case of a 10% owner of an
     incentive stock option) of the fair market value on the date of the
     granting of the option;

          (c) extend the maximum option period under Section 5(b) of the Plan;
     or

          (d) otherwise materially increase the benefits accruing to
     participants under, or materially modify the requirements as to eligibility
     for participation in, the Plan.

          The Committee may amend the terms of any AWARD theretofore granted,
prospectively or retroactively, but no such amendment shall impair the rights of
any holder without such holder's consent. Notwithstanding the foregoing, the
Board or the Committee may, in its discretion, amend the Plan or terms of any
outstanding AWARD held by a person then subject to Section 16 of the Exchange
Act without the consent of any holder in order to preserve exemptions under said
Section 16 which are or become available from time to time under rules of the
Securities and Exchange Commission. The Committee may also substitute new stock
options for previously granted options, including previously granted options
having higher option prices.

     Section 12. Unfunded Status of the Plan. The Plan is intended to constitute
an "unfunded" plan for incentive and deferred compensation. With respect to any
payments not yet made to a participant or optionee by the Corporation, nothing
contained herein shall give any such participant or optionee any rights that are
greater than those of a general creditor of the Corporation. In its sole
discretion, the Committee may authorize the creation of trusts or other
arrangements to meet the obligations created under the Plan to deliver the
Stock; provided, however, that the existence of such trusts or other
arrangements is consistent with the unfunded status of the Plan.

     Section 13. Employment at Will. Nothing contained in the Plan, or in any
option granted pursuant to the Plan, nor in any agreement made pursuant to the
Plan, shall confer upon any optionee any right with respect to continuance of
employment by the Company or its subsidiaries, nor interfere in any way with the
right of the Company or its subsidiaries to terminate the optionee's employment
at will or change the optionee's compensation at any time.

     Section 14. General Provisions. (a) The Committee may require each
participant purchasing shares pursuant to an AWARD under the Plan to represent
to and agree with the Corporation in writing that such participant is acquiring
the shares without a view to distribution thereof. The certificates for

                                       -14-

<PAGE>

such shares may include any legend which the Committee deems appropriate to
reflect any restrictions on transfer.

          (b) All certificates for shares of the Stock delivered under the Plan
pursuant to any AWARD shall be subject to such stock-transfer orders and other
restrictions as the Committee may deem advisable under the rules, regulations,
and other requirements of the Securities and Exchange Commission, any stock
exchange upon which the Stock is then listed, and any applicable Federal or
state securities law, and the Committee may cause a legend or legends to be put
on any such certificates to make appropriate reference to such restrictions.

          (c) Recipients of shares of restricted stock, deferred stock and other
Stock-based awards under the Plan (other than options) shall not be required to
make any payment or provide consideration other than the rendering of services.

          (d) AWARDS granted under the Plan may, in the discretion of the
Committee, be granted either alone or in addition to, in tandem with, or in
substitution for, any other AWARDS granted under the Plan. If AWARDS are granted
in substitution for other AWARDS, the Committee shall require the surrender of
such other AWARDS in consideration for the grant of the new AWARDS. AWARDS
granted in addition to or in tandem with other AWARDS may be granted either at
the same time as or at a different time from the grant of such other AWARDS. The
exercise price of any option or the purchase price of any Other Stock-based
AWARD in the nature of a purchase right:

               (i) granted in substitution for outstanding AWARDS or in lieu of
          any other right to payment by the Corporation shall be the fair market
          value of shares at the date such substitute AWARDS are granted or
          shall be such fair market value at that date reduced to reflect the
          fair market value of the AWARDS or other right to payment required to
          be surrendered by the participant as a condition to receipt of the
          substitute AWARD; or

               (ii) retroactively granted in tandem with outstanding AWARDS
          shall be either the fair market value of shares at the date of grant
          of later AWARDS or the fair market value of shares at the date of
          grant of earlier AWARDS.

          (e) Nothing contained in this Plan shall prevent the Board of
Directors from adopting other or additional compensation arrangements, subject
to shareholder approval if such approval is required; and such arrangements may
be either generally applicable or applicable only in specific cases.

     Section 15. Taxes. (a) Participants shall make arrangements satisfactory to
the Committee regarding payment of any Federal, state, or local taxes of any
kind required by law to be withheld with respect to any income which the
participant is required, or elects, to include in his gross income and the
Corporation and its subsidiaries shall, to the extent permitted by law, have the
right to deduct any such taxes from any payment of any kind otherwise due to the
participant. Anything contained herein to the contrary notwithstanding, the
Committee may, in its sole discretion, authorize acceptance of Stock received in
connection with the grant or exercise of an AWARD or otherwise previously
acquired in satisfaction of withholding requirements.


                                       -15-

<PAGE>

          (b) Notwithstanding any provisions to the contrary in this Section 15,
an Insider may only satisfy tax withholding requirements with the settlement of
a stock appreciation right or with shares of the Company's Common Stock if he
has held such stock or stock appreciation right for at least six (6) months or
the cash settlement of the tax obligation occurs no earlier than six (6) months
after the date of an irrevocable election made by an Insider.

     Section 16. Effective Date of the Plan. The Plan shall be effective on the
date it is approved by the vote of the holders of a majority of all outstanding
shares of Common Stock.

     Section 17. Term of the Plan. No AWARD shall be granted pursuant to the
Plan after May 23, 2011, but AWARDS theretofore granted may extend beyond that
date.


                                       -16-