Exhibit 4.16

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 THAT SUCH DISPOSITION IS EXEMPT
FROM THE REGISTRATION AND PROSPECTUS DELIVERY REQUIREMENTS OF THE ACT AND OF ANY
APPLICABLE STATE SECURITIES LAWS.

NO. WA2-64                                               ISSUED: APRIL 19, 2004

                      A-2 WARRANT TO PURCHASE COMMON STOCK

                                   ----------

      THIS CERTIFIES THAT, for good and valuable consideration, Franklin M.
Berger (the "HOLDER") is entitled to purchase from Adventrx Pharmaceuticals,
Inc., a Delaware corporation (the "COMPANY"), Thirty-three Thousand Three
Hundred Thirty-three (33,333) 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 Two Dollars and Fifty Cents ($2.50) (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 in whole or part 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) to the principal office of the
      Company. 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 shares of
      Common Stock called for by this Warrant, which new Warrant shall in all
      other respects be identical with this Warrant, or at the request of the
      Holder, appropriate notation may be made on this Warrant and the same
      returned to the Holder.

            (b) 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 purchased pursuant to
      this Warrant, by wire transfer or certified check payable to the order of
      the Company or, at any time following the first anniversary of the Warrant

<PAGE>

      Date, if there is not an effective Registration Statement (as defined in
      the Registration Rights Agreement, dated as of the Warrant Date, between
      the Company and the Holder (the "REGISTRATION RIGHTS AGREEMENT")) with
      respect to all of the Warrant Shares, then at the option of the Holder,
      such amount may be paid by the surrender of a portion of shares of Common
      Stock then held by the Holder or issuable upon such exercise of this
      Warrant, which shall be valued and credited toward such amount due to the
      Company for the exercise of the Warrant based upon the Current Market
      Price of the Common Stock. 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.

            "CURRENT MARKET PRICE" means, in respect of any share of Common
      Stock on any date herein specified,

            (1) if there shall not then be a public market for the Common Stock,
      the higher of

                  (a) the book value per share of Common Stock at such date, and

                  (b) the value per share of Common Stock at such date as
     determined in good faith by the Board,

            or

            (2) if there shall then be a public market for the Common Stock, the
      higher of (x) the book value per share of Common Stock at such date, and
      (y) the average of the daily market prices for the 10 consecutive trading
      days immediately before such date. The daily market price (the "DAILY
      MARKET PRICE") for each such trading day shall be (i) the closing price on
      such day on the principal stock exchange (including Nasdaq) on which such
      Common Stock is then listed or admitted to trading, or quoted, as
      applicable, (ii) if no sale takes place on such day on any such exchange,
      the last reported closing price on such day as officially quoted on any
      such exchange (including Nasdaq), (iii) if the Common Stock is not then
      listed or admitted to trading on any stock exchange, the last reported
      closing bid price on such day in the over-the-counter market, as furnished
      by the National Association of Securities Dealers Automatic Quotation
      System or the National Quotation Bureau, Inc., (iv) if neither such
      corporation at the time is engaged in the business of reporting such
      prices, as furnished by any similar firm then engaged in such business, or
      (v) if there is no such firm, as furnished by any member of the National
      Association of Securities Dealers, Inc. (the "NASD") selected mutually by
      the holder of this Warrant and the Company or, if they cannot agree upon
      such selection, as selected by two such members of the NASD, one of which
      shall be selected by holder of this Warrant and one of which shall be
      selected by the Company.



            (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, but in no
      case later than the date that is three business days following receipt by
      the Company of a Notice of Exercise duly completed and executed.

                                      -2-
<PAGE>

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
shares of its Common Stock 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
      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 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.



                                      -3-
<PAGE>

            (c) Issuance of Additional Shares.

            (I) If at any time after June 30, 2004, the Company shall issue or
            sell any shares of its Common Stock, other than Excluded Shares (as
            that term is defined below) ("ADDITIONAL SHARES"), in exchange for
            consideration in an amount per Additional Share less than the
            Exercise Price at the time the Additional Shares are issued or sold,
            then the Exercise Price immediately prior to such issue or sale
            shall be reduced to a price determined by dividing:

                  (1) an amount equal to the sum of (a) the number of shares of
                  Common Stock outstanding immediately prior to such issue or
                  sale multiplied by the then existing Exercise Price, plus (b)
                  the consideration, if any, received by the Company upon such
                  issue or sale, by

                  (2) the total number of shares of Common Stock outstanding
                  immediately after such issue or sale.

            (II) The provisions of Section 3(c)(i) shall not apply to any deemed
            issuance of Additional Shares for which an adjustment is provided
            under Section 3(a) or 3(b). No adjustment of the number of shares of
            Common Stock acquirable upon exercise of this Warrant shall be made
            under Section 3(c) upon the issuance of any shares of Common Stock
            which are issued pursuant to the exercise of any warrants or other
            subscription or purchase rights or pursuant to the exercise of any
            conversion or exchange rights in any convertible securities, if any
            such adjustment shall previously have been made upon the issuance of
            such warrants or other rights or upon the issuance of such
            convertible securities (or upon the issuance of any warrant or other
            rights therefor) pursuant to Section 3(d).

For purposes of this Warrant the term "EXCLUDED SHARES" means: (i) shares of
Common Stock issuable or issued after the issuance date of this Warrant (the
"WARRANT DATE") (as defined in the Purchase Agreement) to officers, employees,
consultants or directors of the Company directly or pursuant to a stock
purchase, stock option, restricted stock or other written compensation plan or
agreement approved by the Board of Directors of the Company (the "BOARD"); (ii)
shares of Common Stock issued or issuable after the Warrant Date, primarily for
non-equity financing purposes and as approved by the Board, to financial
institutions or lessors in connection with commercial credit arrangements,
equipment financings or similar transactions or to vendors of goods or services
or customers; (iii) shares of Common Stock issuable upon (a) exercise of
warrants, options, notes or other rights to acquire securities of the Company,
in each case, outstanding on the Warrant Date, (b) conversion of shares of the
Company's Preferred Stock, par value $0.01 per share, outstanding on the Warrant
Date, (c) exchange of promissory notes issued by the Company which are
outstanding on the Warrant Date, (iv) the Shares (as such term is defined in the
Common Stock and Warrant Purchase Agreement, dated as of the Warrant Date,
between the Company and the Holder (the "PURCHASE AGREEMENT")); (v) the Warrants
(as such term is defined in the Purchase Agreement); (vi) capital stock or
warrants or options to purchase capital stock issued in connection with bona
fide acquisitions, mergers or similar transactions, the terms of which are


                                      -4-
<PAGE>

approved by the Board; (vii) shares of Common Stock issued or issuable to
licensors of technology of the Company to pay expenses, royalties or milestone
payments for which the Company is obligated under any licensing or related
agreement; (viii) shares of Common Stock issuable or issued pursuant to stock
splits, stock dividends and the like, or (ix) shares of Common Stock issued or
issuable by way of dividend or other distribution on shares of Common Stock
issued pursuant to clauses (i) - (viii) above.

      (d)   Issuance of Common Stock Equivalents.

            (i) If at any time while this Warrant is outstanding the Company
            shall issue or sell any warrants or other rights to subscribe for or
            purchase any additional shares of Common Stock or any securities
            convertible into shares of Common Stock (other than the Additional
            Shares) (collectively, o "COMMON STOCK EQUIVALENTS"), whether or not
            the rights to exchange or convert thereunder are immediately
            exercisable, and the effective price per share for which Common
            Stock is issuable upon the exercise, exchange or conversion of such
            Common Stock Equivalents shall be less than the Exercise Price in
            effect immediately prior to the time of such issue or sale, then the
            Exercise Price shall be adjusted as provided in Section 3(c) on the
            basis that the maximum number of additional shares of Common Stock
            issuable pursuant to all such Common Stock Equivalents shall be
            deemed to have been issued and outstanding and the Company shall
            have received all of the consideration payable therefor, if any, as
            of the date of the actual issuance of such Common Stock Equivalents.
            No further adjustments to the current Warrant Price shall be made
            under this Section 3(d) upon the actual issue of such Common Stock
            upon the exercise, conversion or exchange of such Common Stock
            Equivalents.

            (ii) Upon the expiration or termination of any such Common Stock
            Equivalents, the Exercise Price, to the extent in any way affected
            by or computed using such Common Stock o Equivalents, shall be
            recomputed to reflect the issuance of the total number of shares of
            Common Stock (and convertible or exchangeable securities which
            remain in effect) actually issued upon the exercise, exchange or
            conversion of such Common Stock Equivalents to the extent that this
            Warrant is then outstanding.

      (e) Other Action Affecting Common Stock. In case at any time or from time
to time the Company shall take any action in respect of its Common Stock, other
than the payment of dividends permitted by Section 3 or any other action
described in Section 3, then, unless such action will not have a materially
adverse effect upon the rights of the Holder, the number of shares of Common
Stock or other stock into which this Warrant is exercisable and/or the purchase
price thereof shall be adjusted in such manner as may be equitable in the
circumstances.

      (f) Certificate as to Adjustments. Upon the occurrence of each adjustment
or readjustment of the Exercise Price, the Company, at its expense, shall
promptly compute such adjustment or readjustment in accordance with the terms
hereof and prepare and furnish to the Holder of this Warrant a certificate
setting forth such adjustment or readjustment and showing in detail the facts


                                      -5-
<PAGE>

upon which such adjustment or readjustment is based. The Company shall, upon the
written request at any time of the Holder of this Warrant, furnish or cause to
be furnished to such Holder a like certificate setting forth (i) such
adjustments and readjustments, (ii) the Exercise Price at the time in effect and
(iii) the number of shares of Common Stock and the amount, if any, or other
property which at the time would be received upon the exercise of Warrants owned
by such Holder.

      (g) Notice of Corporate Action. If at any time:

            (i) the Company shall take a record of the holders of its Common
      Stock for the purpose of entitling them to receive a dividend (other than
      a cash dividend payable out of earnings or earned surplus legally
      available for the payment of dividends under the laws of the jurisdiction
      of incorporation of the Company) or other distribution, or any right to
      subscribe for or purchase any evidences of its indebtedness, any shares of
      stock of any class or any other securities or property, or to receive any
      other right, or

            (ii) there shall be any capital reorganization of the Company, any
      reclassification or recapitalization of the capital stock of the Company
      or any consolidation or merger of the Company with, or any sale, transfer
      or other disposition of all or substantially all the property, assets or
      business of the Company to, another corporation, or

            (iii) there shall be a voluntary or involuntary dissolution,
      liquidation or winding up of the Company;

      then, in any one or more of such cases, the Company shall give to the
      Holder (i) at least 10-days' prior written notice of the date on which a
      record date shall be selected for such dividend, distribution or right or
      for determining rights to vote in respect of any such reorganization,
      reclassification, merger, consolidation, sale, transfer, disposition,
      dissolution, liquidation or winding up, and (ii) in the case of any such
      reorganization, reclassification, merger, consolidation, sale, transfer,
      disposition, dissolution, liquidation or winding up, at least 10-days'
      prior written notice of the date when the same shall take place. Such
      notice in accordance with the foregoing clause also shall specify (i) the
      date on which any such record is to be taken for the purpose of such
      dividend, distribution or right, the date on which the holders of Common
      Stock shall be entitled to any such dividend, distribution or right, and
      the amount and character thereof, and (ii) the date on which any such
      reorganization, reclassification, merger, consolidation, sale, transfer,
      disposition, dissolution, liquidation or winding up is to take place and
      the time, if any such time is to be fixed, as of which the holders of
      Common Stock shall be entitled to exchange their shares of Common Stock
      for securities or other property deliverable upon such reorganization,
      reclassification, merger, consolidation, sale, transfer, disposition,
      dissolution, liquidation or winding up. Each such written notice shall be
      sufficiently given if addressed to the Holder at the last address of the
      Holder appearing on the books of the Company and delivered in accordance
      with Section 11(d).

4. TRANSFER OF WARRANT. This Warrant may only be transferred in compliance with
federal and state securities laws; 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.
If, at the time of the surrender of this Warrant in connection with any transfer
of this Warrant or the resale of the Warrant Shares, this Warrant or the Warrant


                                      -6-
<PAGE>

Shares, as applicable, shall not be registered under the Securities Act of 1933,
as amended (the SECURITIES ACT"), the Company may require, as a condition of
allowing such transfer (i) that the Holder or transferee of this Warrant or the
Warrant Shares as the case may be, furnish to the Company a written opinion of
counsel that is reasonably acceptable to the Company to the effect that such
transfer may be made without registration under the Securities Act, (ii) that
the Holder or transferee execute and deliver to the Company an investment letter
in form and substance acceptable to the Company and substantially in the form
attached as Exhibit B hereto and (iii) that the transferee be an "accredited
investor" as defined in Rule 501(a) promulgated under the Securities Act.
Transfer of this Warrant, and all rights hereunder, in whole or in part, in
accordance with the foregoing provisions, shall be registered on the books of
the Company to be maintained for such purpose, upon surrender of this Warrant to
the principal office of the Company or the office or agency designated by the
Company, together with a written assignment of this Warrant substantially in the
form of Exhibit C hereto duly executed by the Holder or its attorney-in-fact 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 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. Following
a transfer that complies with the requirements of this Section 4, the Warrant
may be exercised by a new holder for the purchase of shares of Common Stock
regardless of whether the Company issued or registered a new Warrant on the
books of the Company. This Section 4 shall survive the exercise or expiration of
the Warrant.

5. CONDITIONS TO EXERCISE OF WARRANT.

            (a) 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 SECURITIES REPRESENTED HEREBY HAVE NOT BEEN REGISTERED UNDER THE
      SECURITIES ACT OF 1933 (THE "ACT") AND MAY NOT BE OFFERED, SOLD OR
      OTHERWISE TRANSFERRED, PLEDGED OR HYPOTHECATED UNLESS AND UNTIL REGISTERED
      UNDER THE ACT OR, IN THE OPINION OF COUNSEL IN FORM AND SUBSTANCE
      SATISFACTORY TO THE ISSUER OF THESE SECURITIES, SUCH OFFER, SALE OR
      TRANSFER, PLEDGE OR HYPOTHECATION IS IN COMPLIANCE THEREWITH.

            (b) REMOVAL OF LEGEND AND TRANSFER RESTRICTIONS. Any legend endorsed
      on a certificate pursuant to this Section 5 shall be removed, and the
      Company shall issue a certificate without such legend to the holder of
      such Warrant Shares if (i) such Warrant Shares are resold pursuant to a
      registration statement under the Securities Act, and a prospectus meeting
      the requirements of Section 10 of the Securities Act is delivered or
      deemed delivered to the purchaser of such Warrant Shares, (ii) if such
      holder satisfies the requirements of Rule 144(k) or


                                      -7-
<PAGE>

(iii) if such holder provides the Company with an opinion of counsel for such
holder of the Warrant Shares, reasonably satisfactory to the Company, to the
effect that a sale, transfer or assignment of such Warrant Shares may be made
without registration. This paragraph shall survive any exercise of this Warrant.

            (c) RESTRICTIONS ON EXERCISE AMOUNT. Unless a Holder delivers to the
      Company irrevocable written notice (x) prior to the date of issuance
      hereof or 61 days prior to the effective date of such notice that this
      Section 5(c) shall not apply to such Holder or (y) prior to a Change of
      Control, the Holder may not acquire a number of Warrant Shares to the
      extent that, upon such exercise, the number of shares of Common Stock then
      beneficially owned by such Holder and its affiliates and any other persons
      or entities whose beneficial ownership of Common Stock would be aggregated
      with the Holder's for purposes of Section 13(d) of the Securities Exchange
      Act of 1934, as amended (the "EXCHANGE ACT"), (including shares held by
      any "group" of which the Holder is a member, but excluding shares
      beneficially owned by virtue of the ownership of securities or rights to
      acquire securities that have limitations on the right to convert, exercise
      or purchase similar to the limitation set forth herein) exceeds 9.99% of
      the total number of shares of Common Stock of the Company then issued and
      outstanding. For purposes hereof, "group" has the meaning set forth in
      Section 13(d) of the Exchange Act and applicable regulations of the
      Securities and Exchange Commission (the "COMMISSION"), and the percentage
      held by the holder shall be determined in a manner consistent with the
      provisions of Section 13(d) of the Exchange Act. Each delivery of a notice
      of exercise by a Holder will constitute a representation by such Holder
      that it has evaluated the limitation set forth in this paragraph and
      determined, based on the most recent public filings by the Company with
      the Commission, that the issuance of the full number of Warrant Shares
      requested in such notice of exercise is permitted under this paragraph.

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. REGISTRATION RIGHTS. The Holder shall have the registration rights described
in the Registration Rights Agreement.

8. RIGHTS OF STOCKHOLDERS. No Holder shall be entitled, in its capacity 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 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.

9. TERM OF WARRANT. This Warrant shall become exercisable on the Warrant Date
and shall no longer be exercisable as of the earlier of (i) 5:00 p.m., San
Diego, California local time, on the date that is the five-year anniversary of
the Warrant Date; and (ii) upon consummation of a Change of Control.



                                      -8-
<PAGE>

10. REDEMPTION AT COMPANY'S ELECTION. The Company may at the option of the
Board, by at least seven-days' prior written notice to the Holder (the
"REDEMPTION NOTICE"), redeem this Warrant, in whole or in part, at any time
after June 30, 2004, provided that (i) the Daily Market Price for twenty
consecutive trading days is equal to or greater than the product of (x) 2
multiplied by (y) the Exercise Price, (ii) either (A) all of the Warrant Shares
underlying this Warrant to be redeemed are then registered under an effective
registration statement or (B) may be sold pursuant to Rule 144 during a
three-month period without registration under the Securities Act, (iii)
sufficient shares of Common Stock of the Company are authorized and reserved for
issuance upon the full exercise of this Warrant, (iv) all of the Warrant Shares
issuable upon exercise of this Warrant are then listed on every stock exchange,
market or bulletin board on which any Common Stock of the Company is then listed
and (v) the Company is not in default of any material provision of any
Transaction Agreement (as defined in the Purchase Agreement). The Redemption
Notice shall set forth a date, not less than seven days after the date of the
Redemption Notice, on which the redemption of this Warrant shall occur (the
"REDEMPTION DATE"). On the Redemption Date, (i) the Company shall pay the Holder
by certified check an amount equal to the product of (x) $0.001 (as adjusted in
proportion to any adjustment to the Exercise Price pursuant to Section 3 hereof)
multiplied by (y) the number of Warrant Shares so redeemed; and (ii) the Holder
shall deliver the original copy of this Warrant marked "REDEEMED" to the
Company. If the Company shall redeem this Warrant in part, the Company shall, at
the Redemption Date, provided that the Holder shall have delivered the original
copy of this Warrant marked "REDEEMED" to the Company, deliver to the Holder a
new Warrant evidencing the rights of the Holder to purchase the unredeemed
shares of Common Stock called for by this Warrant, which new Warrant shall in
all other respects be identical with this Warrant. Nothing in this Section 10
shall prevent the exercise of the Warrants at any time prior to the Redemption
Date.

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
      or sent by confirmed facsimile or telecopy, (b) one day after sending,
      when sent by commercial overnight courier with written verification of
      receipt, or (c) three business days after deposit with the United States
      Postal Service, when mailed postage prepaid by certified or registered
      mail, return receipt requested, addressed if to the Company, at 9948
      Hibert Street, Suite 100, San Diego, CA 92131, facsimile: (858) 271-9678,


                                      -9-
<PAGE>

      Attention: Nicholas J. Virca, or, 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).

            (e) Except as may otherwise be provided herein, 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.]


                                      -10-
<PAGE>

                                                                    Exhibit 4.16

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

            Issued :  April 19, 2004.

                                        ADVENTRX PHARMACEUTICALS, INC.

                                        By:    /s/ Evan. M. Levine
                                               ---------------------------------
                                        Name:  Evan. M. Levine
                                               ---------------------------------
                                        Title: Chief Operating Officer
                                               ---------------------------------








           SIGNATURE PAGE TO THE A-2 WARRANT TO PURCHASE COMMON STOCK

<PAGE>


                                    EXHIBIT A

                               NOTICE OF EXERCISE

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

      1. The undersigned hereby elects to purchase ____________ 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 A-2 Warrant to Purchase Common Stock dated
___________ 2004 (the "WARRANT"), and tenders herewith payment of the purchase
price of such shares in full.

      2. The undersigned hereby elects to convert the attached Warrant into
Common Stock of Adventrx Pharmaceuticals, Inc. through "cashless exercise" in
the manner specified in the Warrant. This conversion is exercised with respect
to _____________________ of the Shares covered by the Warrant.

      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:       _________________________________

                                 _________________________________

      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 with respect to the Warrant and Warrant Shares (as
defined in the Warrant) set forth in Section 4 of the Purchase Agreement (as
defined in the Warrant) were true and correct as of the Warrant Date (as defined
in the Warrant) and are true and correct as of the date hereof.

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

                                              By:     _________________________

                                              Name:   _________________________

                                              Title:  _________________________

                                              Date:   _________________________


<PAGE>

                                    EXHIBIT B

                    FORM OF INVESTMENT REPRESENTATION LETTER

In connection with the acquisition of [warrants (the "Warrants") to purchase
_______ shares of Common Stock of Adventrx Pharmaceuticals, Inc. (the
"Company"), par value $0.001 per share (the "Common Stock")][________ shares of
Common Stock of Adventrx Pharmaceuticals, Inc. (the "Company"), par value $0.001
per share (the "Common Stock")], by _______________ (the "Holder") from
_____________, the Holder hereby represents and warrants to the Company as
follows:


The Holder (i) is an "Accredited Investor" as that term is defined in Rule 501
of Regulation D promulgated under the Securities Act of 1933, as amended (the
"Act"); and (ii) has the ability to bear the economic risks of such Holder's
prospective investment, including a complete loss of Holder's investment in the
Warrants and the shares of Common Stock issuable upon the exercise thereof
(collectively, the "Securities").

The Holder, by acceptance of the Warrants, represents and warrants to the
Company that the Warrants and all securities acquired upon any and all exercises
of the Warrants are purchased for the Holder's own account, and not with view to
distribution of either the Warrants or any securities purchasable upon exercise
thereof in violation of applicable securities laws.

The Holder acknowledges that (i) the Securities have not been registered under
the Act, (ii) the Securities are "restricted securities" and the certificate(s)
representing the Securities shall bear the following legend, or a similar legend
to the same effect, until (i) in the case of the shares of Common Stock
underlying the Warrants, such shares shall have been registered for resale by
the Holder under the Act and effectively been disposed of in accordance with a
registration statement that has been declared effective; or (ii) in the opinion
of counsel for the Company such Securities may be sold without registration
under the Act:

"[NEITHER] THE SECURITIES REPRESENTED BY THIS CERTIFICATE [NOR THE SECURITIES
INTO WHICH THEY ARE EXERCISABLE] HAVE [NOT] BEEN REGISTERED UNDER THE SECURITIES
ACT OF 1933, AS AMENDED (THE "ACT"), AND ALL SUCH SECURITIES ARE SUBJECT TO
RESTRICTIONS ON TRANSFERABILITY AS SET FORTH IN THIS CERTIFICATE. [NEITHER] THE
SECURITIES REPRESENTED HEREBY [NOR THE SECURITIES INTO WHICH THEY ARE
EXERCISABLE] MAY [NOT] BE SOLD, TRANSFERRED, OR OTHERWISE DISPOSED OF IN THE
ABSENCE OF AN EFFECTIVE REGISTRATION STATEMENT UNDER THE ACT OR AN OPINION OF
COUNSEL, REASONABLY ACCEPTABLE TO COUNSEL FOR THE COMPANY, TO THE EFFECT THAT
THE PROPOSED SALE, TRANSFER, OR DISPOSITION MAY BE EFFECTUATED WITHOUT
REGISTRATION UNDER THE ACT."

IN WITNESS WHEREOF, the Holder has caused this Investment Representation Letter
to be executed in its corporate name by its duly authorized officer this __ day
of __________ 200_.


[Name]


By:______________________________
Name:
Title:


<PAGE>

                                    EXHIBIT C

                                 ASSIGNMENT FORM

FOR VALUE RECEIVED the undersigned registered owner of this Warrant for the
purchase of shares of Common Stock of Adventrx Pharmaceuticals, Inc. hereby
sells, assigns and transfers unto the Assignee named below all of the rights of
the undersigned under this Warrant, with respect to the number of shares of
common stock set forth below:


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

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

---------------------------------------
(Name and Address of Assignee)

---------------------------------------
(Number of Shares of Common Stock)


and does hereby irrevocably constitute and appoint ____________ attorney-in-fact
to register such transfer on the books of the Company, maintained for the
purpose, with full power of substitution in the premises.


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

--------------------------------------
(Print Name and Title)

--------------------------------------
(Signature)

--------------------------------------
(Witness)


NOTICE: The signature on this assignment must correspond with the name as
written upon the face of the Warrant in every particular, without alteration or
enlargement or any change whatsoever.