Exhibit 10.4 NEITHER THIS SECURITY NOR THE SECURITIES INTO WHICH THIS SECURITY IS EXERCISABLE HAS BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM REGISTRATION...

                                                                    Exhibit 10.4

NEITHER THIS SECURITY NOR THE SECURITIES INTO WHICH THIS SECURITY IS EXERCISABLE
HAS BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE
SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM
REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN
AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE
SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO
SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE
COMPANY.

                          COMMON STOCK PURCHASE WARRANT

                  To Purchase 50,000 Shares of Common Stock of

                         KERYX BIOPHARMACEUTICALS, INC.

        THIS COMMON STOCK PURCHASE WARRANT CERTIFIES that, for value received,
Xxxxxx & Xxxxxxx, Inc. (the "Holder"), is entitled, upon the terms and subject
to the limitations on exercise and the conditions hereinafter set forth, at any
time on or after November 20, 2003 (the "Initial Exercise Date") and on or prior
to the close of business on November 20, 2008 (the "Termination Date") but not
thereafter, to subscribe for and purchase from Keryx Biopharmaceuticals, Inc., a
corporation incorporated in the State of Delaware (the "Company"), up to 50,000
shares (the "Warrant Shares") of Common Stock, par value $0.001 per share, of
the Company (the "Common Stock"). The purchase price of one share of Common
Stock (the "Exercise Price") under this Warrant shall be $6.00, subject to
adjustment hereunder. The Exercise Price and the number of Warrant Shares for
which the Warrant is exercisable shall be subject to adjustment as provided
herein. CAPITALIZED TERMS USED AND NOT OTHERWISE DEFINED HEREIN SHALL HAVE THE
MEANINGS SET FORTH IN THAT CERTAIN SECURITIES PURCHASE AGREEMENT (THE "PURCHASE
AGREEMENT"), DATED NOVEMBER 12, 2003, BETWEEN THE COMPANY AND THE PURCHASERS
SIGNATORY THERETO.

        1. Title to Warrant. Prior to the Termination Date and subject to
compliance with applicable laws and Section 7 of this Warrant, this Warrant and
all rights hereunder are transferable, in whole or in part, at the office or
agency of the Company by the Holder in person or by duly authorized attorney,
upon surrender of this Warrant together with the Assignment Form annexed hereto
properly endorsed. The transferee shall sign an investment letter in form and
substance reasonably satisfactory to the Company.

        2. Authorization of Shares. The Company covenants that all Warrant
Shares which may be issued upon the exercise of the purchase rights represented
by this Warrant will, upon exercise of the purchase 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).

        3. Exercise of Warrant.

              (a) Exercise of the purchase rights represented by this Warrant
      may be made at any time or times on or after the Initial Exercise Date and
      on or before the Termination Date by the surrender of this Warrant and the
      Notice of Exercise 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 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 by wire transfer or
      cashier's check drawn on a United States bank, if applicable, or by means
      of a cashless exercise pursuant to Section 3(c), the Holder shall be
      entitled to receive a certificate for the number of Warrant Shares so
      purchased. Certificates for shares purchased hereunder shall be delivered
      to the


                                       1

      Holder within four (4) Trading Days after the date on which this Warrant
      shall have been exercised as aforesaid. This Warrant shall be deemed to
      have been exercised and such certificate or certificates shall be deemed
      to have been issued, and the Holder or any other person so designated to
      be named therein shall be deemed to have become a holder of record of such
      shares for all purposes, as of the date the Warrant has been exercised by
      payment to the Company of the Exercise Price and all taxes required to be
      paid by the Holder, if any, pursuant to Section 5 prior to the issuance of
      such shares, have been paid.

              (b) If this Warrant shall have been exercised in part, the Company
      shall, at the time of delivery of the certificate or certificates
      representing Warrant Shares, deliver to the Holder a new Warrant
      evidencing the rights of the Holder to purchase the unpurchased Warrant
      Shares called for by this Warrant, which new Warrant shall in all other
      respects be identical with this Warrant.

              (c) If at any time after one year from the Issuance Date there is
      no effective Registration Statement registering the resale of the Warrant
      Shares by the Holder, this Warrant may also be exercised at such time by
      means of a "cashless exercise" in which the Holder shall be entitled to
      receive a certificate for the number of Warrant Shares equal to the
      quotient obtained by dividing [(A-B) (X)] by (A), where:

            (A) = the Closing Price on the Trading Day immediately preceding
                  the date of such election;


            (B) = the Exercise Price of the Warrants, as adjusted; and


            (X) = the number of Warrant Shares issuable upon exercise of this
                  Warrant in accordance with the terms of this Warrant.

        4. No Fractional Shares or Scrip. No fractional shares or scrip
representing fractional shares shall be issued upon the exercise of this
Warrant. As to any fraction of a share which Holder would otherwise be entitled
to purchase upon such exercise, the Company shall pay a cash adjustment in
respect of such final fraction in an amount equal to such fraction multiplied by
the Exercise Price.

        5. Charges, Taxes and Expenses. Issuance of certificates for Warrant
Shares shall be made without charge to the Holder 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 Holder or in such name or names as may be
directed by the Holder; provided, however, that in the event certificates for
Warrant Shares are to be issued in a name other than the name of the Holder,
this Warrant when surrendered for exercise shall be accompanied by the
Assignment Form attached hereto duly executed by the Holder; and the Company may
require, as a condition thereto, the payment of a sum sufficient to reimburse it
for any transfer tax incidental thereto.

        6. Closing of Books. The Company will not close its stockholder books or
records in any manner which prevents the timely exercise of this Warrant,
pursuant to the terms hereof.

        7. Transfer, Division and Combination.

              (a) Subject to compliance with any applicable securities laws and
      the conditions set forth in Sections 1 and 7(e) hereof and to the
      provisions of Section 4.1 of the Purchase Agreement, this Warrant and all
      rights hereunder are transferable, in whole or in part, upon surrender of
      this Warrant at the Trading office of the Company, together with a written
      assignment of this Warrant substantially in the form attached hereto duly
      executed by the Holder or its agent or attorney and funds sufficient to
      pay any transfer taxes payable upon the making of such transfer. Upon such
      surrender and, if required, such payment, the Company shall execute and
      deliver a new Warrant or Warrants in the name of the assignee or assignees
      and in the denomination or denominations


                                        2

      specified in such instrument of assignment, and shall issue to the
      assignor a new Warrant evidencing the portion of this Warrant not so
      assigned, and this Warrant shall promptly be cancelled. A Warrant, if
      properly assigned, may be exercised by a new holder for the purchase of
      Warrant Shares without having a new Warrant issued.

              (b) This Warrant may be divided or combined with other Warrants
      upon presentation hereof at the aforesaid office of the Company, together
      with a written notice specifying the names and denominations in which new
      Warrants are to be issued, signed by the Holder or its agent or attorney.
      Subject to compliance with Section 7(a), as to any transfer which may be
      involved in such division or combination, the Company shall execute and
      deliver a new Warrant or Warrants in exchange for the Warrant or Warrants
      to be divided or combined in accordance with such notice.

              (c) The Company shall prepare, issue and deliver at its own
      expense (other than transfer taxes) the new Warrant or Warrants under this
      Section 7.

              (d) The Company agrees to maintain, at its aforesaid office, books
      for the registration and the registration of transfer of the Warrants.

              (e) If, at the time of the surrender of this Warrant in connection
      with any transfer of this Warrant, the transfer of this Warrant shall not
      be registered pursuant to an effective registration statement under the
      Securities Act and under applicable state securities or blue sky laws, the
      Company may require, as a condition of allowing such transfer (i) that the
      Holder or transferee of this Warrant, as the case may be, furnish to the
      Company a written opinion of counsel (which opinion shall be in form,
      substance and scope customary for opinions of counsel in comparable
      transactions) to the effect that such transfer may be made without
      registration under the Securities Act and under applicable state
      securities or blue sky laws, (ii) that the holder or transferee execute
      and deliver to the Company an investment letter in form and substance
      acceptable to the Company and (iii) that the transferee be an "accredited
      investor" as defined in Rule 501(a) promulgated under the Securities Act.

        8. No Rights as Shareholder until Exercise. This Warrant does not
entitle the Holder to any voting rights or other rights as a shareholder of the
Company prior to the exercise hereof. Upon the surrender of this Warrant and the
payment of the aggregate Exercise Price (or by means of a cashless exercise),
the Warrant 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
later of the date of such surrender or payment.

        9. Loss, Theft, Destruction or Mutilation of Warrant. The Company
covenants that upon receipt by the Company of evidence reasonably satisfactory
to it of the loss, theft, destruction or mutilation of this Warrant or any stock
certificate relating to the Warrant Shares, and in case of loss, theft or
destruction, of indemnity or security reasonably satisfactory to it (which, in
the case of the Warrant, shall not include the posting of any bond), 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 such 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 Saturday,
Sunday or legal holiday.

        11. Adjustments of Exercise Price and Number of Warrant Shares. The
number and kind of securities purchasable upon the exercise of this Warrant and
the Exercise Price shall be subject to adjustment from time to time upon the
happening of any of the following. In case the Company shall (i) pay a dividend
in shares of Common Stock or make a distribution in shares of Common Stock to
all


                                       3

holders of its outstanding Common Stock, (ii) subdivide its outstanding shares
of Common Stock into a greater number of shares, (iii) combine its outstanding
shares of Common Stock into a smaller number of shares of Common Stock, or (iv)
issue any shares of its capital stock in a reclassification of the Common Stock,
then the number of Warrant Shares purchasable upon exercise of this Warrant
immediately prior thereto shall be adjusted so that the Holder shall be entitled
to receive the kind and number of Warrant Shares or other securities of the
Company which it would have owned or have been entitled to receive had such
Warrant been exercised in advance thereof. Upon each such adjustment of the kind
and number of Warrant Shares or other securities of the Company which are
purchasable hereunder, the Holder shall thereafter be entitled to purchase the
number of Warrant Shares or other securities resulting from such adjustment at
an Exercise Price per Warrant Share or other security obtained by multiplying
the Exercise Price in effect immediately prior to such adjustment by the number
of Warrant Shares purchasable pursuant hereto immediately prior to such
adjustment and dividing by the number of Warrant Shares or other securities of
the Company resulting from such adjustment. An adjustment made pursuant to this
paragraph shall become effective immediately after the effective date of such
event retroactive to the record date, if any, for such event.

        12. Reclassification, Merger, Consolidation or Disposition of Assets. In
case the Company shall reclassify its Common Stock, consolidate or merge with or
into another corporation (where the Company is not the surviving corporation),
or sell, transfer or otherwise dispose of all or substantially all its property,
assets or business to another corporation and, pursuant to the terms of such
reclassification, merger, consolidation or disposition of assets, shares of
common stock of the successor or acquiring corporation, or any cash, shares of
stock or other securities or property of any nature whatsoever (including
warrants or other subscription or purchase rights) in addition to or in lieu of
common stock of the successor or acquiring corporation ("Other Property"), are
to be received by or distributed to the holders of Common Stock of the Company,
then the Holder shall have the right thereafter to receive, upon exercise of
this Warrant, the number of shares of common stock of the successor or acquiring
corporation and Other Property receivable upon or as a result of such
reclassification, merger, consolidation or disposition of assets by a holder of
the total number of shares of Common Stock for which this Warrant is exercisable
immediately prior to such event. In case of any such reclassification, merger,
consolidation or disposition of assets, the successor or acquiring corporation
(if other than the Company) shall expressly assume the due and punctual
observance and performance of each and every covenant and condition of this
Warrant to be performed and observed by the Company and all the obligations and
liabilities hereunder, subject to such modifications as may be deemed
appropriate (as determined in good faith by resolution of the Board of Directors
of the Company) in order to provide for adjustments of Warrant Shares for which
this Warrant is exercisable which shall be as nearly equivalent as practicable
to the adjustments provided for in this Section 12. For purposes of this Section
12, "common stock of the successor or acquiring corporation" shall include stock
of such corporation of any class which is not preferred as to dividends or
assets over any other class of stock of such corporation and which is not
subject to redemption and shall also include any evidences of indebtedness,
shares of stock or other securities which are convertible into or exchangeable
for any such stock, either immediately or upon the arrival of a specified date
or the happening of a specified event and any warrants or other rights to
subscribe for or purchase any such stock. The foregoing provisions of this
Section 12 shall similarly apply to successive reorganizations,
reclassifications, mergers, consolidations or disposition of assets.

        13. Voluntary Adjustment by the Company. The Company may at any time
during the term of this Warrant reduce the then current Exercise Price to any
amount and for any period of time deemed appropriate by the Board of Directors
of the Company.

        14. 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 give notice thereof to the Holder, which notice shall state 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 (and other
securities or property) 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.


                                       4

        15. 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 to provide for the issuance of the Warrant
Shares 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 who are charged with the duty of executing stock
certificates to execute and issue the necessary certificates for the Warrant
Shares 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
Warrant Shares may be issued as provided herein without violation of any
applicable law or regulation, or of any requirements of the Trading Market upon
which the Common Stock may be listed.

        Except and to the extent as waived or consented to by the Holder, the
Company shall not by any action, including, without limitation, amending its
certificate of incorporation or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issue or sale of securities or any other
voluntary action, intentionally avoid or seek to avoid the observance or
performance of any of the express terms of this Warrant, but will at all times
in good faith assist in the carrying out of all such terms. Without limiting the
generality of the foregoing, the Company will (a) not increase the par value of
any Warrant Shares above the amount payable therefor upon such exercise
immediately prior to such increase in par value, (b) take all such action as may
be necessary or appropriate in order that the Company may validly and legally
issue fully paid and nonassessable Warrant Shares upon the exercise of this
Warrant, and (c) use commercially reasonable efforts to obtain all such
authorizations, exemptions or consents from any public regulatory body having
jurisdiction thereof as may be necessary to enable the Company to perform its
obligations under this Warrant.

        Before taking any action which would result in an adjustment in the
number of Warrant Shares for which this Warrant is exercisable or in the
Exercise Price, the Company shall obtain all such authorizations or exemptions
thereof, or consents thereto, as may be necessary from any public regulatory
body or bodies having jurisdiction thereof.

        16. Miscellaneous.

              (a) Jurisdiction. This Warrant shall constitute a contract under
      the laws of New York, without regard to its conflict of law, principles or
      rules.

              (b) Restrictions. The Holder acknowledges that the Warrant Shares
      acquired upon the exercise of this Warrant will have restrictions upon
      resale imposed by state and federal securities laws and will have an
      appropriate legend imprinted thereon.

              (c) Nonwaiver. No course of dealing or any delay or failure to
      exercise any right hereunder on the part of the Holder shall operate as a
      waiver of such right or otherwise prejudice the Holder's rights, powers or
      remedies, notwithstanding all rights hereunder terminate on the
      Termination Date.

              (d) Notices. Any notice, request or other document required or
      permitted to be given or delivered to the Holder by the Company shall be
      delivered in accordance with the notice provisions of the Purchase
      Agreement; provided that upon any permitted assignment of this Warrant,
      the assignee shall promptly provide the Company with its contact
      information.

              (e) Limitation of Liability. No provision hereof, in the absence
      of any affirmative action by the Holder to exercise this Warrant or
      purchase Warrant Shares, and no enumeration herein of the rights or
      privileges of Holder, shall give rise to any liability of Holder for the
      purchase price of any Common Stock or as a stockholder of the Company,
      whether such liability is asserted by the Company or by creditors of the
      Company.


                                        5

              (f) Remedies. The Holder, in addition to being entitled to
      exercise all rights granted by law, including recovery of damages, will be
      entitled to specific performance of its rights under this Warrant. The
      Company agrees that monetary damages would not be adequate compensation
      for any loss incurred by reason of a breach by it of the provisions of
      this Warrant and hereby agrees to waive the defense in any action for
      specific performance that a remedy at law would be adequate.

              (g) Successors and Assigns. Subject to applicable securities laws,
      this Warrant and the rights and obligations evidenced hereby shall inure
      to the benefit of and be binding upon the successors of the Company and
      the successors and permitted assigns of the Holder. The provisions of this
      Warrant are intended to be for the benefit of all Holders from time to
      time of this Warrant and shall be enforceable by any such Holder or holder
      of Warrant Shares.

              (h) Amendment. This Warrant may be modified or amended or the
      provisions hereof waived with the written consent of the Company and the
      Holder.

              (i) Severability. Wherever possible, each provision of this
      Warrant shall be interpreted in such manner as to be effective and valid
      under applicable law, but if any provision of this Warrant shall be
      prohibited by or invalid under applicable law, such provision shall be
      ineffective to the extent of such prohibition or invalidity, without
      invalidating the remainder of such provisions or the remaining provisions
      of this Warrant.

              (j) Headings. The headings used in this Warrant are for the
      convenience of reference only and shall not, for any purpose, be deemed a
      part of this Warrant.


                                        6

        IN WITNESS WHEREOF, the Company has caused this Warrant to be executed
by its officer thereunto duly authorized.

Dated: November __, 2003
                               KERYX BIOPHARMACEUTICALS, INC.

                               By:
                                  ---------------------------------------------
                                  Name: Xxxxxxx X. Xxxxx
                                  Title: Chairman and Chief Executive Officer


                                       7

                               NOTICE OF EXERCISE

To: Keryx Biopharmaceuticals, Inc.

        (1) The undersigned hereby elects to purchase           Warrant Shares
of Keryx Biopharmaceuticals, Inc. pursuant to the terms of the attached Warrant
(only if exercised in full), and tenders herewith payment of the exercise price
in full, together with all applicable transfer taxes, if any.

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

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

The Warrant Shares shall be delivered to the following:

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

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

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

        (3) Accredited Investor. The undersigned is an "accredited investor" as
defined in Regulation D promulgated under the Securities Act of 1933, as
amended.

                               [PURCHASER]

                               By:
                                     -----------------------------------
                                     Name:
                                     Title:

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


                                       8

                                 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.


                                        9