Document:

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                                                                    EXHIBIT 4.31

THIS WARRANT HAS BEEN, AND THE SHARES OF COMMON STOCK WHICH MAY BE RECEIVED
PURSUANT TO THE EXERCISE OF THIS WARRANT WILL BE, ACQUIRED SOLELY FOR INVESTMENT
AND NOT WITH A VIEW TO, OR FOR RESALE IN CONNECTION WITH, ANY DISTRIBUTION
THEREOF. NEITHER THIS WARRANT NOR SUCH SHARES (TOGETHER, THE "SECURITIES") HAVE
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR ANY
STATE SECURITIES LAWS. SUCH SECURITIES MAY NOT BE SOLD, OFFERED FOR SALE,
PLEDGED OR HYPOTHECATED IN THE ABSENCE OF SUCH REGISTRATION OR AN OPINION OF
COUNSEL REASONABLY SATISFACTORY TO THE COMPANY AND ITS COUNSEL THAT SUCH
DISPOSITION IS EXEMPT FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS
OF THE ACT AND OF ANY APPLICABLE STATE SECURITIES LAWS.

NO. WC-290               ORIGINAL ISSUE DATE 10/15/03- (TRANSFERRED FROM WC-288)

                        WARRANT TO PURCHASE COMMON STOCK

                                   ----------

     THIS CERTIFIES THAT, for good and valuable consideration, ROBERT J.
NEBORSKY MD INC COMBINATION RETIREMENT TRUST (the "HOLDERS") are entitled to
subscribe for and purchase from Adventrx Pharmaceuticals, Inc., a Delaware
corporation (the "COMPANY"), TWENTY-THOUSAND, EIGHTY-ONE (20,081) fully paid and
nonassessable shares of Common Stock, par value $0.001 per share ("COMMON
STOCK"), of the Company (as adjusted pursuant to Section 3 hereof) (the "WARRANT
SHARES") at a price per share equal to One Dollar and Twenty Five Cents ($1.25)
(as adjusted pursuant to Section 3 hereof) (the "EXERCISE PRICE"), subject to
the provisions and upon the terms and conditions hereinafter set forth.

1. METHOD OF EXERCISE; PAYMENT.

          (A) Exercise Period. The purchase right represented by this Warrant
     may be exercised by the Holder during the term of this Warrant (as set
     forth in Section 9 hereof) at any time after the Commencement Date, as
     defined below, by the surrender of this Warrant (with the notice of
     exercise form attached hereto as Exhibit A (the "NOTICE OF EXERCISE") duly
     executed) at the principal office of the Company. This Warrant may only be
     exercised in whole and not in part.

          (B) Cash Exercise. Upon exercise of this Warrant, the Holder shall pay
     the Company an amount equal to the product of (x) the Exercise Price
     multiplied by (y) the total number of Warrant Shares subject to this
     Warrant, by wire transfer or certified check payable to the order of the
     Company. The person or persons in whose name(s) any certificate(s)
     representing the Warrant Shares shall be issuable upon exercise of this
     Warrant shall be deemed to have become the holder(s) of record of, and
     shall be treated for all purposes as the record holder(s) of, the Warrant
     Shares represented thereby (and such Warrant Shares shall be deemed to have
     been issued) immediately prior to the close of business on the date upon
     which this Warrant is exercised.

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          (C) Stock Certificates. In the event of the exercise of this Warrant,
     certificates for the Warrant Shares so purchased shall be delivered to the
     Holder within a reasonable time after exercise.

2. STOCK FULLY PAID; RESERVATION OF SHARES. All of the Warrant Shares issuable
upon the exercise of the rights represented by this Warrant will, upon issuance
and receipt of the Exercise Price therefor, be fully paid and nonassessable, and
free from all preemptive rights, rights of first refusal or first offer, taxes,
liens and charges with respect to the issuance thereof. During the period within
which the rights represented by this Warrant may be exercised, the Company shall
at all times have authorized and reserved for issuance a sufficient number of
Warrant Shares to provide for the exercise of the rights represented by this
Warrant.

3. ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF SHARES. The number and kind of
Warrant Shares purchasable upon the exercise of this Warrant and the Exercise
Price therefor shall be subject to adjustment from time to time upon the
occurrence of certain events, as follows:

          (A) Reclassification, Consolidation or Reorganization. In case of any
     reclassification of the Common Stock (other than a change in par value, or
     as a result of a subdivision or combination), or in case of any
     consolidation or merger of the Company with or into another corporation
     (other than a Change of Control, as defined below) (any of which is a
     "REORGANIZATION TRANSACTION"), the Company, or such successor corporation
     as the case may be, shall execute a new warrant, providing that the holder
     of this Warrant shall have the right to exercise such new warrant, and
     procure upon such exercise and payment of the same aggregate Exercise
     Price, in lieu of the Warrant Shares theretofore issuable upon exercise of
     this Warrant, the kind and amount of shares of stock, other securities,
     money and property as would be payable for the Warrant Shares issuable upon
     exercise of this Warrant as if such Warrant Shares were outstanding on the
     consummation of the Reorganization Transaction. For purposes of this
     Warrant, the term "CHANGE OF CONTROL" shall mean (i) any acquisition of the
     Company by means of merger, acquisition, or other form of corporate
     reorganization in which outstanding shares of the Company are exchanged for
     securities or other consideration issued, or caused to be issued, by the
     acquiring corporation or its subsidiary or parent (other than a
     reincorporation transaction or change of domicile) and pursuant to which
     the holders of the outstanding voting securities of the Company immediately
     prior to such consolidation, merger or other transaction fail to hold
     equity securities representing a majority of the voting power of the
     Company or surviving entity immediately following such consolidation,
     merger or other transaction (excluding voting securities of the acquiring
     corporation held by such holders prior to such transaction) or (ii) a sale
     of all or substantially all of the assets of the Company.

          (B) Stock Splits, Dividends and Combinations. In the event that the
     Company shall at any time subdivide the outstanding shares of Common Stock,
     or shall issue a stock dividend on its outstanding shares of Common Stock,
     the number of Warrant Shares issuable upon exercise of this Warrant
     immediately prior to such subdivision or to the issuance of such stock
     dividend shall be proportionately increased, and the Exercise Price shall
     be proportionately decreased, and in the event that the Company shall at
     any time combine the outstanding shares of Common Stock, the number of
     Warrant Shares issuable upon exercise

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     of this Warrant immediately prior to such combination shall be
     proportionately decreased, and the Exercise Price shall be proportionately
     increased, effective at the close of business on the date of such
     subdivision, stock dividend or combination, as the case may be.

4. TRANSFER OF WARRANT. This Warrant may only be transferred in compliance with
federal and state securities laws and, except as provided below, may not be
transferred except with the prior written consent of the Company, which shall
not be unreasonably withheld or delayed, and any purported transfer without such
prior written consent shall be null and void; provided, however, that the
Company may withhold its consent to transfer or assignment of this Warrant to
any person or entity who is deemed to be a competitor or prospective competitor
of the Company, such determination to be made in the reasonable judgment of the
Board.

5. CONDITION TO EXERCISE OF WARRANT. Each certificate evidencing the Warrant
Shares issued upon exercise of this Warrant shall be stamped or imprinted with a
legend substantially in the following form:

          THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR
          INVESTMENT AND NOT WITH A VIEW TO, OR FOR RESALE IN CONNECTION WITH,
          ANY DISTRIBUTION THEREOF, AND HAVE NOT BEEN REGISTERED UNDER THE
          SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR ANY STATE
          SECURITIES LAWS. SUCH SECURITIES MAY NOT BE SOLD, OFFERED FOR SALE,
          PLEDGED OR HYPOTHECATED IN THE ABSENCE OF SUCH REGISTRATION OR AN
          OPINION OF COUNSEL SATISFACTORY TO THE COMPANY AND ITS COUNSEL THAT
          SUCH REGISTRATION IS NOT REQUIRED UNDER THE ACT OR UNLESS SOLD
          PURSUANT TO RULE 144 OF SUCH ACT.

6. FRACTIONAL SHARES. No fractional Warrant Shares will be issued in connection
with any exercise hereunder, but in lieu of such fractional shares the Company
shall make a cash payment therefor upon the basis of the Exercise Price then in
effect.

7. REPRESENTATIONS AND WARRANTIES BY THE HOLDER. The Holder represents and
warrants to the Company as follows:

          (A) This Warrant is being acquired for the Holder's own account, for
     investment and not with a view to, or for resale in connection with, any
     distribution or public offering thereof within the meaning of the
     Securities Act of 1933, as amended (the "SECURITIES ACT"). Upon exercise of
     this Warrant, the Holder shall, if so requested by the Company, confirm in
     writing, in a form reasonably satisfactory to the Company, that the Warrant
     Shares issuable upon exercise of this Warrant are being acquired for
     investment and not with a view toward distribution or resale. The Holder is
     an "accredited investor" within the meaning of the Securities Act.

          (B) The Holder understands that this Warrant and the Warrant Shares
     have not been registered under the Securities Act by reason of their
     issuance in a transaction exempt from the registration and prospectus
     delivery requirements of the Securities Act pursuant to Section 4(2)
     thereof and that the Company's reliance upon such exemption is predicated,
     in

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     part, upon the Holder's representations and warranties set forth in this
     Agreement. The Holder understands that this Warrant and the Warrant Shares
     must be held by the Holder indefinitely, and that the Holder must therefore
     bear the economic risk of such investment indefinitely, unless a subsequent
     disposition thereof is registered under the Securities Act or is exempted
     from such registration. The Holder further understands that this Warrant
     and the Warrant Shares have not been registered under the securities laws
     of any state.

          (C) The Holder acknowledges that it is acquiring this Warrant without
     being offered or furnished any offering literature or prospectus. The
     Holder understands that neither the United States Securities and Exchange
     Commission, nor any governmental agency charged with the administration of
     the securities laws of any state nor any other governmental agency has
     passed upon or reviewed the merits or qualifications of, or recommended or
     approved the issuance of this Warrant or the Warrant Shares.

          (D) The Holder understands that, except as provided in Section 10 of
     this Warrant, the Company is under no obligation to register this Warrant
     or the Warrant Shares.

          (E) The Holder is a bona fide resident and domiciliary (not a
     temporary or transient resident) of the state indicated in the signature
     page hereto and the Holder has no present intention of becoming a resident
     of any other state or jurisdiction.

          (F) The Holder has such knowledge and experience in financial and
     business matters that it is capable of evaluating the merits and risks of
     the purchase of this Warrant and the Warrant Shares purchasable pursuant to
     the terms of this Warrant and of protecting its interests in connection
     therewith. The Holder is able to bear the economic risk of the purchase of
     the Warrant Shares pursuant to the terms of this Warrant.

          (G) The Holder does not currently have and will not undertake during
     the term of this Warrant any short position with respect to shares of
     Common Stock of the Company.

8. RIGHTS OF STOCKHOLDERS. No holder of this Warrant shall be entitled, as a
Warrant holder, to vote or receive dividends or be deemed the holder of Warrant
Shares or any other securities of the Company which may at any time be issuable
on the exercise hereof for any purpose, nor shall anything contained herein be
construed to confer upon the Holder any of the rights of a stockholder of the
Company or any right to vote for the election of directors or upon any matter
submitted to stockholders at any meeting thereof, or to give or withhold consent
to any corporate action (whether upon any recapitalization, issuance of stock,
reclassification of stock, change of par value, consolidation, merger,
conveyance, or otherwise) or to receive notice of meetings, or to receive
dividends or subscription rights or otherwise with respect to the Warrant Shares
until this Warrant shall have been exercised and the Warrant Shares purchasable
upon the exercise hereof shall have become deliverable, as provided herein.

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9. TERM OF WARRANT.

          (A) This Warrant shall become exercisable on the date of issuance set
     forth below (the "COMMENCEMENT DATE") and shall no longer be exercisable as
     of the earlier of (i) 5:00 p.m., San Diego, California local time, on
     October 15, 2006; (ii) immediately prior to a Change of Control and (iii)
     5:00 p.m., San Diego, California local time, on the Call Termination Date
     (as defined below).

          (B) Notwithstanding anything herein to the contrary, at any time after
     the Commencement Date, if the closing price of one share of Common Stock
     quoted in the over-the-counter market summary, the Bulletin Board Exchange,
     the Nasdaq National Market or the closing price quoted on a national
     securities exchange, whichever is applicable, is greater than or equal to
     200% of the Exercise Price for a period of 20 consecutive trading days,
     then thereafter the Company shall have the right (the "COMPANY TERMINATION
     RIGHT"), exercisable at the Company's sole discretion, to terminate this
     Warrant with at least 10-days' prior written notice (the "TERMINATION
     NOTICE") which Termination Notice shall state the date this Warrant shall
     terminate (the "CALL TERMINATION DATE"); provided, however, that the
     Company may not exercise the Company Termination Right unless a
     registration statement registering the Warrant Stock has been declared
     effective and is effective from the date of delivery of the Termination
     Notice until the Call Termination Date, provided, further, that if this
     Warrant is terminated pursuant to this Section 9(b), then the Company shall
     use commercially reasonable efforts to maintain the effectiveness of a
     registration statement registering the Warrant Stock until the date that is
     15 days after the Call Termination Date or, if earlier, the date the Holder
     shall have sold all its Warrant Shares covered by such registration
     statement.

10. REGISTRATION RIGHTS.

          (A) Piggy-back Rights. If (but without any obligation to do so) the
     Company proposes to register any shares of Common Stock solely for cash
     pursuant to a registration statement under the Securities Act, other than a
     registration solely in connection with a transaction under Rule 145
     promulgated under the Securities Act (a "PUBLIC OFFERING"), the Company
     shall promptly give the Holder written notice of such Public Offering, at
     least 10 business days prior to the filing of the registration statement
     under the Securities Act regarding such Public Offering. Upon the written
     request of the Holder given within 5 business days after delivery of such
     written notice by the Company, the Company shall, subject to the provisions
     of Section 10(b) below, use its best efforts to cause to be registered
     under the Securities Act all of the Warrant Shares that the Holder has
     requested to be registered.

          (B) Underwriting. If the registration statement under which the
     Company gives notice under this Section 10 is for an underwritten Public
     Offering, the Company shall so advise the Holder. The right of the Holder
     to registration pursuant to Section 10(a) above shall be conditioned upon
     the Holder's participation in such underwriting and the inclusion of the
     Warrant Shares in the underwriting to the extent provided herein. The
     Holder shall (together with the Company and any other holders of Company
     securities distributing their securities through such underwriting) enter
     into an underwriting agreement in customary

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     form with the underwriter or underwriters selected for underwriting by the
     Company. Notwithstanding any other provision of this Section 10, if the
     underwriter determines that marketing factors require a limitation of the
     number of shares to be underwritten, the underwriter may exclude some or
     all of the Warrant Shares from such registration and underwriting.

          (C) Furnish Information. It shall be a condition to the Company's
     obligations to take any action under this Section 10 that the Holder shall
     furnish to the Company such information regarding itself, the Warrant
     Shares, and the intended method of disposition of such Warrant Shares as
     shall be required to effect the registration of any Warrant Shares. In that
     connection, the Holder shall be required to represent to the Company that
     all such information which is given is both complete and accurate in all
     material respects when made.

          (D) Delay of Registration. The Holder shall have no right to obtain or
     seek an injunction restraining or otherwise delaying any such registration
     as the result of any controversy that might arise with respect to the
     interpretation or implementation of this Section 10.

          (E) Termination of Registration Rights. The Company shall have no
     obligation to register Warrant Shares pursuant to this Section 10 with
     respect to any request or requests made by any Holder on or after that date
     which is one year after the date such Warrant Shares were deemed to be
     acquired for purposes of determining the holding period of such Warrant
     Shares under Rule 144 of the Act.

11. MISCELLANEOUS.

          (A) This Warrant is being delivered in the state of California and
     shall be construed and enforced in accordance with and governed by the laws
     of the state of California, without giving effect to principles of
     conflicts of laws.

          (B) The headings in this Warrant are for purposes of reference only,
     and shall not limit or otherwise affect any of the terms hereof.

          (C) The terms of this Warrant shall be binding upon and shall inure to
     the benefit of any successors or assigns of the Company and of the Holder
     and of the Warrant Shares issued or issuable upon the exercise hereof.

          (D) Any notice provided for or permitted under this Warrant shall be
     treated as having been given (a) upon receipt, when delivered personally,
     (b) upon receipt, when sent by confirmed facsimile or telecopy, (c) one day
     after sending, when sent by commercial overnight courier with written
     verification of receipt, or (d) three business days after deposit with the
     United States Postal Service, when mailed postage prepaid by certified or
     registered mail, return receipt requested, addressed (a) if to the Company,
     at 9948 Hibert Street, Suite 100, San Diego, CA 92131, facsimile: (858)
     271-9678, Attention: Nicholas J. Virca, or (b) if to the Holder, at such
     address or facsimile number as the Holder shall have furnished to the
     Company in writing, or at such other place of which the other party has
     been notified in accordance with the provisions of this Section 11(d).

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          (E) This Warrant constitutes the full and entire understanding and
     agreement between the parties with regard to the subjects hereof.

          (F) Upon receipt of evidence reasonably satisfactory to the Company of
     the loss, theft, destruction or mutilation of this Warrant and, in the case
     of any such loss, theft or destruction, upon delivery of an indemnity
     agreement reasonably satisfactory in form and amount to the Company or, in
     the case of any such mutilation, upon surrender and cancellation of such
     Warrant, the Company at the Holder's expense will execute and deliver to
     the holder of record, in lieu thereof, a new Warrant of like date and
     tenor.

          (G) This Warrant and any provision hereof may be amended, waived or
     terminated only by an instrument in writing signed by the Company and the
     Holder.

          (H) Receipt of this Warrant by the Holder shall constitute acceptance
     of and agreement to the foregoing terms and conditions.

                            [Signature page follows.]

                                        7

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

     Issue Date: October 15, 2003

                                        ADVENTRX PHARMACEUTICALS, INC.

                                        By: /s/ Carrie Carlander
                                            ------------------------------------
                                            Carrie Carlander
                                            Chief Financial Officer
                                            April 15, 2005

                                        ROBERT J. NEBORSKY MD INC COMBINATION
                                        RETIREMENT TRUST

                                        By: /s/ Sandra Neborsky
                                            ------------------------------------

                                        By: /s/ Robert Neborsky
                                            ------------------------------------

                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------
                                        Address:
                                                 -------------------------------

                                                 -------------------------------
                                        Facsimile:
                                                   -----------------------------

                                        8

<PAGE>

                                    EXHIBIT A

                               NOTICE OF EXERCISE

TO: Adventrx Pharmaceuticals, Inc.
    9948 Hibert Street, Suite 100
    San Diego, CA 92131

RE: WC-290

     The undersigned hereby elects to purchase 20,081 shares of Common Stock,
par value $0.001 per share, of the Company ("COMMON STOCK") pursuant to the
terms of Section 1(b) of the Warrant to Purchase Common Stock dated October 15,
2003 (the "WARRANT"), and tenders herewith payment of the purchase price of such
shares in full.

     Please issue a certificate or certificates representing said 20,081 shares
of Common Stock in the name of the undersigned or in such other name as is
specified below:

                                        Name:
                                              ----------------------------------
                                        Address:
                                                 -------------------------------

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

     The undersigned hereby represents and warrants that the aforesaid shares of
Common Stock are being acquired for the account of the undersigned for
investment and not with a view to, or for resale, in connection with the
distribution thereof, and that the undersigned has no present intention of
distributing or reselling such shares, and that all representations and
warranties of the undersigned set forth in Section 7 of the Warrant are true and
correct as of the date hereof.

                                        ROBERT J. NEBORSKY MD INC COMBINATION
                                        RETIREMENT TRUST

                                        By:
                                            ------------------------------------

                                        By:
                                            ------------------------------------
                                        Names:
                                               ---------------------------------
                                        Title:
                                               ---------------------------------
                                        Date:
                                              ----------------------------------<PAGE>
                                                                    EXHIBIT 4.33

THIS WARRANT HAS BEEN, AND THE SHARES OF COMMON STOCK WHICH MAY BE RECEIVED
PURSUANT TO THE EXERCISE OF THIS WARRANT WILL BE, ACQUIRED SOLELY FOR INVESTMENT
AND NOT WITH A VIEW TO, OR FOR RESALE IN CONNECTION WITH, ANY DISTRIBUTION
THEREOF. NEITHER THIS WARRANT NOR SUCH SHARES (TOGETHER, THE "SECURITIES") HAVE
BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR ANY
STATE SECURITIES LAWS. SUCH SECURITIES MAY NOT BE SOLD, OFFERED FOR SALE,
PLEDGED OR HYPOTHECATED IN THE ABSENCE OF SUCH REGISTRATION OR AN OPINION OF
COUNSEL REASONABLY SATISFACTORY TO THE COMPANY AND ITS COUNSEL THAT SUCH
DISPOSITION IS EXEMPT FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS
OF THE ACT AND OF ANY APPLICABLE STATE SECURITIES LAWS.

NO. WC-292                INITIAL ISSUE DATE: 12/04/03

REISSUED 06/15/05 AS RESULT OF TRANSFER FROM WC-275

                        WARRANT TO PURCHASE COMMON STOCK

                                   ----------

     THIS CERTIFIES THAT, for good and valuable consideration, S. NEBORSKY AND R
NEBORSKY TTEE ROBERT J. NEBORSKY MD INC COMB RETIREMENT TRUST (the "HOLDER") is
entitled to subscribe for and purchase from Adventrx Pharmaceuticals, Inc., a
Delaware corporation (the "COMPANY"), SIXTY-SEVEN THOUSAND, FIVE HUNDRED
(67,500) fully paid and nonassessable shares of Common Stock, par value $0.001
per share ("COMMON STOCK"), of the Company (as adjusted pursuant to Section 3
hereof) (the "WARRANT SHARES") at a price per share equal to Fifty Cents ($.50)
(as adjusted pursuant to Section 3 hereof) (the "EXERCISE PRICE"), subject to
the provisions and upon the terms and conditions hereinafter set forth.

1. METHOD OF EXERCISE; PAYMENT.

          (A) Exercise Period. The purchase right represented by this Warrant
     may be exercised by the Holder during the term of this Warrant (as set
     forth in Section 9 hereof) at any time after the Commencement Date, as
     defined below, by the surrender of this Warrant (with the notice of
     exercise form attached hereto as Exhibit A (the "NOTICE OF EXERCISE") duly
     executed) at the principal office of the Company. This Warrant may only be
     exercised in whole and not in part.

          (B) Cash Exercise. Upon exercise of this Warrant, the Holder shall pay
     the Company an amount equal to the product of (x) the Exercise Price
     multiplied by (y) the total number of Warrant Shares subject to this
     Warrant, by wire transfer or certified check payable to the order of the
     Company. The person or persons in whose name(s) any certificate(s)
     representing the Warrant Shares shall be issuable upon exercise of this
     Warrant shall be deemed to have become the holder(s) of record of, and
     shall be treated for all purposes as the record holder(s) of, the Warrant
     Shares represented thereby (and such Warrant Shares shall

<PAGE>

     be deemed to have been issued) immediately prior to the close of business
     on the date upon which this Warrant is exercised.

          (C) Stock Certificates. In the event of the exercise of this Warrant,
     certificates for the Warrant Shares so purchased shall be delivered to the
     Holder within a reasonable time after exercise.

2. STOCK FULLY PAID; RESERVATION OF SHARES. All of the Warrant Shares issuable
upon the exercise of the rights represented by this Warrant will, upon issuance
and receipt of the Exercise Price therefor, be fully paid and nonassessable, and
free from all preemptive rights, rights of first refusal or first offer, taxes,
liens and charges with respect to the issuance thereof. During the period within
which the rights represented by this Warrant may be exercised, the Company shall
at all times have authorized and reserved for issuance a sufficient number of
Warrant Shares to provide for the exercise of the rights represented by this
Warrant.

3. ADJUSTMENT OF EXERCISE PRICE AND NUMBER OF SHARES. The number and kind of
Warrant Shares purchasable upon the exercise of this Warrant and the Exercise
Price therefor shall be subject to adjustment from time to time upon the
occurrence of certain events, as follows:

          (A) Reclassification, Consolidation or Reorganization. In case of any
     reclassification of the Common Stock (other than a change in par value, or
     as a result of a subdivision or combination), or in case of any
     consolidation or merger of the Company with or into another corporation
     (other than a Change of Control, as defined below) (any of which is a
     "REORGANIZATION TRANSACTION"), the Company, or such successor corporation
     as the case may be, shall execute a new warrant, providing that the holder
     of this Warrant shall have the right to exercise such new warrant, and
     procure upon such exercise and payment of the same aggregate Exercise
     Price, in lieu of the Warrant Shares theretofore issuable upon exercise of
     this Warrant, the kind and amount of shares of stock, other securities,
     money and property as would be payable for the Warrant Shares issuable upon
     exercise of this Warrant as if such Warrant Shares were outstanding on the
     consummation of the Reorganization Transaction. For purposes of this
     Warrant, the term "CHANGE OF CONTROL" shall mean (i) any acquisition of the
     Company by means of merger, acquisition, or other form of corporate
     reorganization in which outstanding shares of the Company are exchanged for
     securities or other consideration issued, or caused to be issued, by the
     acquiring corporation or its subsidiary or parent (other than a
     reincorporation transaction or change of domicile) and pursuant to which
     the holders of the outstanding voting securities of the Company immediately
     prior to such consolidation, merger or other transaction fail to hold
     equity securities representing a majority of the voting power of the
     Company or surviving entity immediately following such consolidation,
     merger or other transaction (excluding voting securities of the acquiring
     corporation held by such holders prior to such transaction) or (ii) a sale
     of all or substantially all of the assets of the Company.

          (B) Stock Splits, Dividends and Combinations. In the event that the
     Company shall at any time subdivide the outstanding shares of Common Stock,
     or shall issue a stock dividend on its outstanding shares of Common Stock,
     the number of Warrant Shares issuable upon exercise of this Warrant
     immediately prior to such subdivision or to the issuance of such

<PAGE>

     stock dividend shall be proportionately increased, and the Exercise Price
     shall be proportionately decreased, and in the event that the Company shall
     at any time combine the outstanding shares of Common Stock, the number of
     Warrant Shares issuable upon exercise of this Warrant immediately prior to
     such combination shall be proportionately decreased, and the Exercise Price
     shall be proportionately increased, effective at the close of business on
     the date of such subdivision, stock dividend or combination, as the case
     may be.

4. TRANSFER OF WARRANT. This Warrant may only be transferred in compliance with
federal and state securities laws and, except as provided below, may not be
transferred except with the prior written consent of the Company, which shall
not be unreasonably withheld or delayed, and any purported transfer without such
prior written consent shall be null and void; provided, however, that the
Company may withhold its consent to transfer or assignment of this Warrant to
any person or entity who is deemed to be a competitor or prospective competitor
of the Company, such determination to be made in the reasonable judgment of the
Board.

5. CONDITION TO EXERCISE OF WARRANT. Each certificate evidencing the Warrant
Shares issued upon exercise of this Warrant shall be stamped or imprinted with a
legend substantially in the following form:

          THE SHARES REPRESENTED BY THIS CERTIFICATE HAVE BEEN ACQUIRED FOR
          INVESTMENT AND NOT WITH A VIEW TO, OR FOR RESALE IN CONNECTION WITH,
          ANY DISTRIBUTION THEREOF, AND HAVE NOT BEEN REGISTERED UNDER THE
          SECURITIES ACT OF 1933, AS AMENDED (THE "ACT"), OR ANY STATE
          SECURITIES LAWS. SUCH SECURITIES MAY NOT BE SOLD, OFFERED FOR SALE,
          PLEDGED OR HYPOTHECATED IN THE ABSENCE OF SUCH REGISTRATION OR AN
          OPINION OF COUNSEL SATISFACTORY TO THE COMPANY AND ITS COUNSEL THAT
          SUCH REGISTRATION IS NOT REQUIRED UNDER THE ACT OR UNLESS SOLD
          PURSUANT TO RULE 144 OF SUCH ACT.

6. FRACTIONAL SHARES. No fractional Warrant Shares will be issued in connection
with any exercise hereunder, but in lieu of such fractional shares the Company
shall make a cash payment therefor upon the basis of the Exercise Price then in
effect.

7. REPRESENTATIONS AND WARRANTIES BY THE HOLDER. The Holder represents and
warrants to the Company as follows:

          (A) This Warrant is being acquired for the Holder's own account, for
     investment and not with a view to, or for resale in connection with, any
     distribution or public offering thereof within the meaning of the
     Securities Act of 1933, as amended (the "SECURITIES ACT"). Upon exercise of
     this Warrant, the Holder shall, if so requested by the Company, confirm in
     writing, in a form reasonably satisfactory to the Company, that the Warrant
     Shares issuable upon exercise of this Warrant are being acquired for
     investment and not with a view toward distribution or resale. The Holder is
     an "accredited investor" within the meaning of the Securities Act.

<PAGE>

          (B) The Holder understands that this Warrant and the Warrant Shares
     have not been registered under the Securities Act by reason of their
     issuance in a transaction exempt from the registration and prospectus
     delivery requirements of the Securities Act pursuant to Section 4(2)
     thereof and that the Company's reliance upon such exemption is predicated,
     in part, upon the Holder's representations and warranties set forth in this
     Agreement. The Holder understands that this Warrant and the Warrant Shares
     must be held by the Holder indefinitely, and that the Holder must therefore
     bear the economic risk of such investment indefinitely, unless a subsequent
     disposition thereof is registered under the Securities Act or is exempted
     from such registration. The Holder further understands that this Warrant
     and the Warrant Shares have not been registered under the securities laws
     of any state.

          (C) The Holder acknowledges that it is acquiring this Warrant without
     being offered or furnished any offering literature or prospectus. The
     Holder understands that neither the United States Securities and Exchange
     Commission, nor any governmental agency charged with the administration of
     the securities laws of any state nor any other governmental agency has
     passed upon or reviewed the merits or qualifications of, or recommended or
     approved the issuance of this Warrant or the Warrant Shares.

          (D) The Holder understands that, except as provided in Section 10 of
     this Warrant, the Company is under no obligation to register this Warrant
     or the Warrant Shares.

          (E) The Holder is a bona fide resident and domiciliary (not a
     temporary or transient resident) of the state indicated in the signature
     page hereto and the Holder has no present intention of becoming a resident
     of any other state or jurisdiction.

          (F) The Holder has such knowledge and experience in financial and
     business matters that it is capable of evaluating the merits and risks of
     the purchase of this Warrant and the Warrant Shares purchasable pursuant to
     the terms of this Warrant and of protecting its interests in connection
     therewith. The Holder is able to bear the economic risk of the purchase of
     the Warrant Shares pursuant to the terms of this Warrant.

          (G) The Holder does not currently have and will not undertake during
     the term of this Warrant any short position with respect to shares of
     Common Stock of the Company.

8. RIGHTS OF STOCKHOLDERS. No holder of this Warrant shall be entitled, as a
Warrant holder, to vote or receive dividends or be deemed the holder of Warrant
Shares or any other securities of the Company which may at any time be issuable
on the exercise hereof for any purpose, nor shall anything contained herein be
construed to confer upon the Holder any of the rights of a stockholder of the
Company or any right to vote for the election of directors or upon any matter
submitted to stockholders at any meeting thereof, or to give or withhold consent
to any corporate action (whether upon any recapitalization, issuance of stock,
reclassification of stock, change of par value, consolidation, merger,
conveyance, or otherwise) or to receive notice of meetings, or to receive
dividends or subscription rights or otherwise with respect to the Warrant Shares
until this Warrant shall have been exercised and the Warrant Shares purchasable
upon the exercise hereof shall have become deliverable, as provided herein.

<PAGE>

9. TERM OF WARRANT.

          (A) This Warrant shall become exercisable on the date of issuance set
     forth below (the "COMMENCEMENT DATE") and shall no longer be exercisable as
     of the earlier of (i) 5:00 p.m., San Diego, California local time, on
     December 4, 2006 (ii) immediately prior to a Change of Control and (iii)
     5:00 p.m., San Diego, California local time, on the Call Termination Date
     (as defined below).

          (B) Notwithstanding anything herein to the contrary, at any time after
     the Commencement Date, if the closing price of one share of Common Stock
     quoted in the over-the-counter market summary, the Bulletin Board Exchange,
     the Nasdaq National Market or the closing price quoted on a national
     securities exchange, whichever is applicable, is greater than or equal to
     200% of the Exercise Price for a period of 20 consecutive trading days,
     then thereafter the Company shall have the right (the "COMPANY TERMINATION
     RIGHT"), exercisable at the Company's sole discretion, to terminate this
     Warrant with at least 10-days' prior written notice (the "TERMINATION
     NOTICE") which Termination Notice shall state the date this Warrant shall
     terminate (the "CALL TERMINATION DATE"); provided, however, that the
     Company may not exercise the Company Termination Right unless a
     registration statement registering the Warrant Stock has been declared
     effective and is effective from the date of delivery of the Termination
     Notice until the Call Termination Date, provided, further, that if this
     Warrant is terminated pursuant to this Section 9(b), then the Company shall
     use commercially reasonable efforts to maintain the effectiveness of a
     registration statement registering the Warrant Stock until the date that is
     15 days after the Call Termination Date or, if earlier, the date the Holder
     shall have sold all its Warrant Shares covered by such registration
     statement.

10. REGISTRATION RIGHTS.

          (A) Piggy-back Rights. If (but without any obligation to do so) the
     Company proposes to register any shares of Common Stock solely for cash
     pursuant to a registration statement under the Securities Act, other than a
     registration solely in connection with a transaction under Rule 145
     promulgated under the Securities Act (a "PUBLIC OFFERING"), the Company
     shall promptly give the Holder written notice of such Public Offering, at
     least 10 business days prior to the filing of the registration statement
     under the Securities Act regarding such Public Offering. Upon the written
     request of the Holder given within 5 business days after delivery of such
     written notice by the Company, the Company shall, subject to the provisions
     of Section 10(b) below, use its best efforts to cause to be registered
     under the Securities Act all of the Warrant Shares that the Holder has
     requested to be registered.

          (B) Underwriting. If the registration statement under which the
     Company gives notice under this Section 10 is for an underwritten Public
     Offering, the Company shall so advise the Holder. The right of the Holder
     to registration pursuant to Section 10(a) above shall be conditioned upon
     the Holder's participation in such underwriting and the inclusion of the
     Warrant Shares in the underwriting to the extent provided herein. The
     Holder shall (together with the Company and any other holders of Company
     securities distributing their securities through such underwriting) enter
     into an underwriting agreement in customary

<PAGE>

     form with the underwriter or underwriters selected for underwriting by the
     Company. Notwithstanding any other provision of this Section 10, if the
     underwriter determines that marketing factors require a limitation of the
     number of shares to be underwritten, the underwriter may exclude some or
     all of the Warrant Shares from such registration and underwriting.

          (C) Furnish Information. It shall be a condition to the Company's
     obligations to take any action under this Section 10 that the Holder shall
     furnish to the Company such information regarding itself, the Warrant
     Shares, and the intended method of disposition of such Warrant Shares as
     shall be required to effect the registration of any Warrant Shares. In that
     connection, the Holder shall be required to represent to the Company that
     all such information which is given is both complete and accurate in all
     material respects when made.

          (D) Delay of Registration. The Holder shall have no right to obtain or
     seek an injunction restraining or otherwise delaying any such registration
     as the result of any controversy that might arise with respect to the
     interpretation or implementation of this Section 10.

          (E) Termination of Registration Rights. The Company shall have no
     obligation to register Warrant Shares pursuant to this Section 10 with
     respect to any request or requests made by any Holder on or after that date
     which is one year after the date such Warrant Shares were deemed to be
     acquired for purposes of determining the holding period of such Warrant
     Shares under Rule 144 of the Act.

11. MISCELLANEOUS.

          (A) This Warrant is being delivered in the state of California and
     shall be construed and enforced in accordance with and governed by the laws
     of the state of California, without giving effect to principles of
     conflicts of laws.

          (B) The headings in this Warrant are for purposes of reference only,
     and shall not limit or otherwise affect any of the terms hereof.

          (C) The terms of this Warrant shall be binding upon and shall inure to
     the benefit of any successors or assigns of the Company and of the Holder
     and of the Warrant Shares issued or issuable upon the exercise hereof.

          (D) Any notice provided for or permitted under this Warrant shall be
     treated as having been given (a) upon receipt, when delivered personally,
     (b) upon receipt, when sent by confirmed facsimile or telecopy, (c) one day
     after sending, when sent by commercial overnight courier with written
     verification of receipt, or (d) three business days after deposit with the
     United States Postal Service, when mailed postage prepaid by certified or
     registered mail, return receipt requested, addressed (a) if to the Company,
     at 9948 Hibert Street, Suite 100, San Diego, CA 92131, facsimile: (858)
     271-9678, Attention: Nicholas J. Virca, or (b) if to the Holder, at such
     address or facsimile number as the Holder shall have furnished to the
     Company in writing, or at such other place of which the other party has
     been notified in accordance with the provisions of this Section 11(d).

<PAGE>

          (E) This Warrant constitutes the full and entire understanding and
     agreement between the parties with regard to the subjects hereof.

          (F) Upon receipt of evidence reasonably satisfactory to the Company of
     the loss, theft, destruction or mutilation of this Warrant and, in the case
     of any such loss, theft or destruction, upon delivery of an indemnity
     agreement reasonably satisfactory in form and amount to the Company or, in
     the case of any such mutilation, upon surrender and cancellation of such
     Warrant, the Company at the Holder's expense will execute and deliver to
     the holder of record, in lieu thereof, a new Warrant of like date and
     tenor.

          (G) This Warrant and any provision hereof may be amended, waived or
     terminated only by an instrument in writing signed by the Company and the
     Holder.

          (H) Receipt of this Warrant by the Holder shall constitute acceptance
     of and agreement to the foregoing terms and conditions.

                            [Signature page follows.]

<PAGE>

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

                                        ADVENTRX PHARMACEUTICALS, INC.

                                        By: /s/ Carrie Carlander
                                            ------------------------------------
                                        Name: Carrie Carlander
                                        Title: Chief Financial Officer   6/15/05

                                        S. NEBORSKY AND R. NEBORSKY TTEE
                                        ROBERT J. NEBORSKY MD INC COMB
                                        RETIREMENT TRUST

                                        By: /s/ Sandra Neborsky
                                            ------------------------------------

                                        By: /s/ Robert Neborsky
                                            ------------------------------------

                                        Name:
                                              ----------------------------------
                                        Title:
                                               ---------------------------------
                                        Address:
                                                 -------------------------------

                                                 -------------------------------
                                        Facsimile:
                                                   -----------------------------

<PAGE>

                                    EXHIBIT A

                               NOTICE OF EXERCISE

TO: Adventrx Pharmaceuticals, Inc.
    9948 Hibert Street, Suite 100
    San Diego, CA 92131

RE: WC-292

     The undersigned hereby elects to purchase 67,500 shares of Common Stock,
par value $0.001 per share, of the Company ("COMMON STOCK") pursuant to the
terms of Section 1(b) of the Warrant to Purchase Common Stock dated December 4,
2003 (the "WARRANT"), and tenders herewith payment of the purchase price of such
shares in full.

     Please issue a certificate or certificates representing said 67,500 shares
of Common Stock in the name of the undersigned or in such other name as is
specified below:

                                        Name:
                                              ----------------------------------
                                        Address:
                                                 -------------------------------

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

     The undersigned hereby represents and warrants that the aforesaid shares of
Common Stock are being acquired for the account of the undersigned for
investment and not with a view to, or for resale, in connection with the
distribution thereof, and that the undersigned has no present intention of
distributing or reselling such shares, and that all representations and
warranties of the undersigned set forth in Section 7 of the Warrant are true and
correct as of the date hereof.

                                        S. NEBORSKY AND ROBERT J. NEBORSKY TTEE
                                        ROBERT J. NEBORSKY MD INC COMB
                                        RETIREMENT TRUST

                                        By:
                                            ------------------------------------

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

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