Document:

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                                                                     Exhibit 4.2
                                                                     -----------

THIS WARRANT HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, OR THE SECURITIES LAWS OF ANY STATE AND MAY NOT BE SOLD, TRANSFERRED OR
OTHERWISE DISPOSED OF EXCEPT PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT OR
EXEMPTION FROM REGISTRATION UNDER THE FOREGOING LAWS. ACCORDINGLY, THIS WARRANT
MAY NOT BE SOLD, TRANSFERRED OR OTHERWISE DISPOSED OF WITHOUT (I) AN OPINION OF
COUNSEL SATISFACTORY TO MGI PHARMA, INC. THAT SUCH SALE, TRANSFER OR OTHER
DISPOSITION MAY LAWFULLY BE MADE WITHOUT REGISTRATION UNDER THE SECURITIES ACT
OF 1933 AND APPLICABLE STATE SECURITIES LAWS OR (II) SUCH REGISTRATION.

                                     FORM OF
                          COMMON STOCK PURCHASE WARRANT

       To Purchase ____________ Shares of Common Stock of MGI PHARMA, Inc.

         For value received, ____________________ (the "Investor") is entitled
to purchase from MGI PHARMA, Inc., a Minnesota corporation (the "Company") at
any time and from time to time after the date hereof until 5:00 p.m.,
Minneapolis local time, on December 1, 2007 (the "Expiration Date") up to
____________ fully paid and non-assessable shares (the "Warrant Shares") of
Common Stock of the Company (the "Common Stock"). The per share purchase price
of the Warrant Shares (the "Exercise Price") shall be $____ The Exercise Price
and the number of shares for which this Warrant is exercisable shall be subject
to adjustment as provided herein.

         This Warrant is subject to the following terms and conditions:

         1. Authorization of Shares. The Company covenants that all shares of
Common Stock which may be issued upon the exercise of rights represented by this
Warrant will, upon exercise of the rights represented by this Warrant, be duly
authorized, validly issued, fully paid and nonassessable and free from all
taxes, liens and charges in respect of the issue thereof (other than taxes in
respect of any transfer occurring contemporaneously with such issue).

         2. Exercise of Warrant. Exercise of the purchase rights represented by
this Warrant may be made at any time or times, in whole or in part, before the
Expiration Date, or such earlier date on which this Warrant may terminate as
provided in paragraph 11 below, by the surrender of this Warrant and the Notice
of Exercise annexed hereto duly executed, to the office of the Company (or such
other office or agency of the Company as it may designate by notice in writing
to the registered holder hereof at the address of such holder appearing on the
books of the Company) and upon payment of the Exercise Price of the shares
thereby purchased; whereupon the holder of this Warrant shall be entitled to
receive a certificate for the number of shares of Common Stock so purchased and
a new Warrant for any unexercised portion of the surrendered Warrant in
substantially the same form hereof. Certificates for shares purchased hereunder
and any new warrant issued upon surrender hereof shall be delivered to the
holder hereof within three business days after the date on which this Warrant
shall have been exercised. Payment of the Exercise Price of the shares may be by
certified check or cashier's check or by wire transfer (of

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same day funds) to the Company in an amount equal to the Exercise Price
multiplied by the number of shares being purchased.

         3. No Fractional Shares. No fractional shares shall be issued upon the
exercise of this Warrant. In lieu of issuing fractional shares, the Company
shall round up to the nearest whole share the number of Warrant Shares due upon
exercise of this Warrant.

         4. Charges, Taxes and Expenses. Issuance of certificates for shares of
Common Stock upon the exercise of this Warrant shall be made without charge to
the holder hereof for any issue or transfer tax or other incidental expense in
respect of the issuance of such certificate, all of which taxes and expenses
shall be paid by the Company, and such certificates shall be issued in the name
of the Investor or in such name or names as may be directed by the holder of
this Warrant; provided, however, that in the event certificates for shares of
Common Stock are to be issued in a name other than the name of the Investor,
this Warrant when surrendered for exercise shall be accompanied by the
Assignment Form attached hereto duly executed by the holder hereof; and provided
further, that upon any transfer involved in the issuance or delivery of any
certificates for shares of Common Stock, the Company may require, as a condition
thereto, the payment of a sum sufficient to reimburse it for any transfer tax
incidental thereto.

         5. Closing of Books. The Company will at no time close its shareholder
books or records in any manner which interferes with the timely exercise of this
Warrant.

         6. No Rights as Shareholder until Exercise. This Warrant does not
entitle the holder hereof to any voting rights or other rights as a shareholder
of the Company prior to the exercise hereof. If, however, at the time of the
surrender of this Warrant and purchase the holder hereof shall be entitled to
exercise this Warrant, the shares so purchased shall be and be deemed to be
issued to such holder as the record owner of such shares as of the close of
business on the date on which this Warrant shall have been exercised.

         7. Investment Representations. The Investor agrees and acknowledges
that it is acquiring this Warrant and will be acquiring the Warrant Shares for
its own account and not with a view to any resale or distribution other than in
accordance with federal and state securities laws. The Investor is an
"accredited investor" within the meaning of Regulation D promulgated under the
Securities Act of 1933, as amended (the "Securities Act").

         8. Assignment and Transfer of Warrant. This Warrant may be assigned by
the surrender of this Warrant and the Assignment Form annexed hereto duly
executed at the office of the Company (or such other office or agency of the
Company as it may designate by notice in writing to the registered holder hereof
at the address of such holder appearing on the books of the Company); provided,
however, that this Warrant may not be resold or otherwise transferred except (i)
in a transaction registered under the Securities Act, or (ii) in a transaction
pursuant to an exemption, if available, from such registration and whereby, if
requested by the Company, an opinion of counsel reasonably satisfactory to the
Company is obtained by the holder of this Warrant to the effect that the
transaction is so exempt.

         9. Loss, Theft, Destruction or Mutilation of Warrant. The Company
represents and warrants that upon receipt by the Company of evidence reasonably
satisfactory to it of the loss,

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theft, destruction or mutilation of any Warrant or stock certificate, and in
case of loss, theft or destruction, of indemnity or security reasonably
satisfactory to it, and upon reimbursement to the Company of all reasonable
expenses incidental thereto, and upon surrender and cancellation of such Warrant
or stock certificate, if mutilated, the Company will make and deliver a new
Warrant or stock certificate of like tenor and dated as of such cancellation, in
lieu of this Warrant or stock certificate.

         10. Saturdays, Sundays, Holidays, etc. If the last or appointed day for
the taking of any action or the expiration of any right required or granted
herein shall be a Saturday, Sunday or a legal holiday, then such action may be
taken or such right may be exercised on the next succeeding day not a legal
holiday.

         11. Consolidation, Merger or Sale of Assets. If, prior to the exercise
of this Warrant, the Company shall at any time consolidate with or merge into
another corporation, the holder of this Warrant will thereafter receive, upon
the exercise thereof in accordance with the terms of this Warrant, the
securities or property to which the holder of the number of shares of Common
Stock then deliverable upon the exercise of this Warrant would have been
entitled upon such consolidation or merger, and the Company shall take such
steps in connection with such consolidation or merger as may be necessary to
assure that the provisions hereof shall thereafter be applicable, as nearly as
reasonably may be, in relation to any securities or property thereafter
deliverable upon the exercise of the Warrant. The Company or the successor
corporation, as the case may be, shall execute and deliver to the holder of this
Warrant a supplemental agreement so providing. A sale of all or substantially
all the assets of the Company for a consideration (apart from the assumption of
obligations) consisting primarily of securities shall be deemed a consolidation
or merger for the foregoing purposes. The provisions of this Section 11 shall
similarly apply to successive mergers or consolidations or sales or other
transfers.

         12. Stock Dividends, Subdivisions, Combinations and Reclassifications.
In case the Company shall at any time after the date hereof (i) declare a
dividend on the Common Stock payable in shares of Common Stock, (ii) subdivide
the outstanding Common Stock, (iii) combine the outstanding Common Stock into a
smaller number of shares, or (iv) issue any shares of its capital stock in a
reclassification of the Common Stock (including any such reclassification in
connection with a consolidation or merger in which the Company is the continuing
corporation), the Exercise Price in effect at the time of the record date for
such dividend or of the effective date of such subdivision, combination or
reclassification, and/or the number and kind of shares of capital stock issuable
upon exercise of this Warrant on such date shall be proportionately adjusted so
that the holder of this Warrant after such time shall be entitled to receive
upon exercise of this Warrant the aggregate number and kind of shares of capital
stock which, if such Warrant had been exercised immediately prior to such date
and at a time when the Common Stock transfer books of the Company were open,
such holder would have owned upon such exercise and been entitled to receive by
virtue of such dividend, subdivision, combination or reclassification. Such
adjustment shall be made successively whenever any event listed above shall
occur.

         13. Notice of Adjustment. Whenever the number of Warrant Shares or
number or kind of securities or other property purchasable upon the exercise of
this Warrant or the Exercise Price is adjusted, as herein provided, the Company
shall promptly give the holder of this Warrant

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notice of such adjustment or adjustments setting forth the number of Warrant
Shares (and other securities or property) purchasable upon the exercise of this
Warrant and the Exercise Price of such Warrant Shares after such adjustment,
setting forth a brief statement of the facts requiring such adjustment and
setting forth the computation by which such adjustment was made. Such notice, in
absence of manifest error, shall be conclusive evidence of the correctness of
such adjustment.

         14. Authorized Shares. The Company covenants that during the period the
Warrant is outstanding, it will reserve from its authorized and unissued Common
Stock a sufficient number of shares of Common Stock to provide for the issuance
of Common Stock upon the exercise of any purchase rights under this Warrant. The
Company further covenants that its issuance of this Warrant shall constitute
full authority to its officers or agents who are charged with the duty of
executing stock certificates to execute and issue the necessary certificates for
shares of the Company's Common Stock upon the exercise of the purchase rights
under this Warrant. The Company will take all such reasonable action as may be
necessary to assure that such shares of Common Stock may be issued as provided
herein without violation of any applicable law or regulation, or of any
requirements of the domestic securities exchange or market upon which the Common
Stock may be listed.

         15. Miscellaneous.

                  (a) Issue Date; Choice of Law; Jurisdiction and Venue. The
         provisions of this Warrant shall be construed and shall be given effect
         in all respects as if it had been issued and delivered by the Company
         on the date hereof. This Warrant shall be binding upon any successors
         or assigns of the Company. This Warrant will be construed and enforced
         in accordance with and governed by the laws of the State of Minnesota,
         without reference to principles of conflicts of law. The Company hereby
         consents to the non-exclusive jurisdiction of any court in the State of
         New York, County of New York and waives any objection based on venue or
         forum non conveniens with respect to any action arising under or
         related to this Warrant.

                  (b) Restrictions. The holder hereof acknowledges that the
         Warrant Shares acquired upon the exercise of this Warrant, if not
         registered (or if no exemption from registration exists), will have
         restrictions upon resale imposed by state and federal securities laws.
         Any certificate evidencing the Warrant Shares issuable upon exercise
         hereof will bear a legend indicating that such securities have not been
         registered under the Securities Act or under any state securities laws
         and may not be sold or offered for sale in the absence of an effective
         registration statement as to the securities under the Securities Act
         and any applicable state securities law or an opinion of counsel
         reasonably satisfactory to the Company that such registration is not
         required.

                  (c) Modification and Waiver. This Warrant and any provisions
         hereof may be changed, waived, discharged or terminated only by an
         instrument in writing signed by the party against which enforcement of
         the same is sought.

                  (d) Notices. All notices, requests, consents and other
         communications hereunder will be in writing, will be mailed (i) if
         within the United States by first-class registered

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         or certified airmail, or nationally recognized overnight express
         courier, postage prepaid, by facsimile or e-mail, or (ii) if delivered
         from outside the United States, by international express courier,
         facsimile or e-mail. All such notices will be deemed given (A) if
         delivered by first-class registered or certified mail, three business
         days after so mailed, (B) if delivered by nationally recognized
         overnight carrier, one business day after so mailed, (C) if delivered
         by International Federal Express, two business days after so mailed,
         and (D) if delivered by facsimile or e-mail, upon electronic
         confirmation of receipt and will be delivered as addressed to the
         e-mail address furnished by the parties to each other or by mail as
         follows:

                  If to the Company, to:

                           MGI PHARMA, Inc.
                           5775 West Old Shakopee Road
                           Suite 100
                           Bloomington, Minnesota 55437
                           Attn:  William C. Brown, Chief Financial Officer

                  With a copy to:

                           Dorsey & Whitney, LLP
                           Suite 1500
                           50 South Sixth Street
                           Minneapolis, Minnesota 55402
                           Attn:  Timothy S. Hearn, Esq.

                  If to the Investor, to:

                           Deerfield Management Company
                           780 Third Avenue--37th Floor
                           New York, New York 10017
                           Attn: Arnold Snider

                  With a copy to:

                           Seward & Kissel LLP
                           One Battery Park Plaza
                           New York, New York 10004
                           Attn:  Gary Wolfe, Esq.

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         IN WITNESS WHEREOF, the Company has caused this Warrant to be executed
and delivered by a duly authorized officer.

Dated: December 2, 2002

                                        MGI PHARMA, INC.

                                        By:
                                            -----------------------------------
                                        Name:
                                              ---------------------------------
                                        Title:
                                               --------------------------------
Name and Address of Investor:
-----------------------------

-----------------------------

-----------------------------

-----------------------------

                                      B-6

<PAGE>

                               NOTICE OF EXERCISE

To: MGI PHARMA, INC.

         (1) The undersigned hereby elects to purchase ________ shares of Common
Stock of mgi pharma, inc. pursuant to the terms of the attached Warrant, and
tenders herewith payment of the purchase price in full, together with all
applicable transfer taxes, if any.

         (2) Please issue a certificate or certificates representing said shares
of Common Stock in the name of the undersigned or in such other name as is
specified below:

                                          -------------------------------
                                          (Name)

                                          -------------------------------
                                          (Address)

                                          -------------------------------
Dated:

------------------------
Signature

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                                 ASSIGNMENT FORM

                    (To assign the foregoing warrant, execute
                   this form and supply required information.
                 Do not use this form to exercise the warrant.)

         FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced
thereby are hereby assigned to

_______________________________________________ whose address is

_____________________________________________________________________________.

_____________________________________________________________________________

                                                      Dated:  ______________,

                           Holder's Signature:
                                               ------------------------------
                           Holder's Address:
                                               ------------------------------

                                               ------------------------------

Signature Guaranteed: ___________________________________________

NOTE: The signature to this Assignment Form must correspond with the name as it
appears on the face of the Warrant, without alteration or enlargement or any
change whatsoever, and must be guaranteed by a bank or trust company. Officers
of corporations and those acting in a fiduciary or other representative capacity
should file proper evidence of authority to assign the foregoing Warrant.<Page>

                                                                     Exhibit 4.0

<Table>
<S>                                 <C>                                                      <C>
  [SEAL]                                                                                                  [SEAL]

                                                    THE AMERICAN CORPORATION
                                     INCORPORATED UNDER THE LAWS OF THE STATE OF DELAWARE

COMMON STOCK                                                                                  SEE REVERSE FOR CERTAIN DEFINITIONS

</Table>

THIS
CERTIFIES
that

is the owner of

    FULLY PAID AND NON-ASSESSABLE SHARES OF THE $.001 PAR VALUE COMMON STOCK

transferable only on the books of the Corporation by the holder hereof in
person or by a duly authorized attorney upon surrender of this certificate
properly endorsed. This certificate is not valid until countersigned by the
Transfer Agent. This certificate and the shares represented hereby are issued
and shall be held subject to all of the provisions of the Certificate of
Incorporation and By-Laws of the Corporation and all amendments thereto,
copies of which are on file with the Transfer Agent, to all of which the
holder of this certificate, by acceptance hereof, assents.
     IN WITNESS WHEREOF, the Corporation has caused this certificate to be
signed by the facsimile signatures of its duly authorized officers and to be
sealed with the facsimile seal of the Corporation.

<Table>
<S>                             <C>                               <C>
                                  CORPORATE
                                    SEAL

                                    2002
                                  DELAWARE

SECRETARY                                                          CHAIRMAN

</Table>

         -C-  SECURITY-COLUMBIAN     UNITED STATES BANKNOTE CORPORATION

<Page>

                           THE AMERICAN CORPORATION

     The following abbreviations, when used in the inscription on the face of
this certificate, shall be construed as though they were written out in full
according to applicable laws or regulations:

<Table>
<S>                                                                    <C>
     TEN COM -- as tenants in common                                    UNIF GIFT MIN ACT -- ______________ Custodian ___________
     TEN ENT -- as tenants by the entireties                                                     (Cust)                 (Minor)
     JT TEN  -- as joint tenants with right                                                  under Uniform Gifts to Minors
                of survivorship and not as                                                   Act ________________________________
                tenants in common                                                                           (State)
</Table>

   Additional abbreviations may also be used though not in the above list.

FOR VALUE RECEIVED, ______________ hereby sells, assigns and transfers unto

PLEASE INSERT SOCIAL SECURITY OR OTHER
   IDENTIFYING NUMBER OF ASSIGNEE
---------------------------------------

---------------------------------------

_______________________________________________________________________________
   (PLEASE PRINT OR TYPEWRITE NAME AND ADDRESS, INCLUDING POSTAL ZIP CODE,
                                 OF ASSIGNEE)

_______________________________________________________________________________

_______________________________________________________________________________

________________________________________________________________________ Shares
of the common stock represented by the within Certificate and does hereby
irrevocably constitute and appoint

______________________________________________________________________ Attorney
to transfer the said stock on the books of the within-named Corporation with
full power of substitution in the premises.

Dated _____________________   _________________________________________________
                              NOTICE: The signature to this assignment must
                              correspond with the name as written upon the
                              face of the Certificate in every particular,
                              without alteration or enlargement or any change
                              whatever.

THESE SECURITIES SHALL BE PROMPTLY DEPOSITED INTO AN ESCROW ACCOUNT UNTIL THE
CLOSING OF THE COMPANY'S INITIAL PUBLIC OFFERING OF SECURITIES AND THE
CLOSING OF A BUSINESS COMBINATION, SUCH AS A MERGER OR ACQUISITION.

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