FORM OF COMMON STOCK PURCHASE WARRANT

Exhibit 4.1

FORM OF COMMON STOCK PURCHASE WARRANT

To Purchase                      Shares of Common Stock of

CELL THERAPEUTICS, INC.

Initial Issuance Date: May 11, 2009

THIS COMMON STOCK PURCHASE WARRANT (the “ Warrant ”) certifies that, for value received,                                          (the “ Holder ”) is entitled, upon the terms and subject to the limitations on exercise and the conditions hereinafter set forth, at any time on or after the Initial Issuance Date (the “ Initial Exercise Date ”) and on or before the close of business on the fifth anniversary of the Initial Exercise Date (the “ Termination Date ”) but not thereafter, to subscribe for and purchase from Cell Therapeutics, Inc., a Washington corporation (the “ Company ”), up to              shares (the “ Warrant Shares ”) of common stock, no par value per share (the “ Common Stock ”), of the Company. The purchase price of one share of Common Stock under this Warrant shall be equal to the Exercise Price, as defined in Section 2(b).

Section 1 . Definitions . Capitalized terms used and not otherwise defined herein shall have the meanings set forth in that certain Securities Purchase Agreement, dated May 11, 2009 (the “ Purchase Agreement ”), among the Company and the Holder and others.

Section 2 . Exercise .

a) Exercise of Warrant . Exercise of the purchase rights represented by this Warrant may be made, in whole or in part, at any time or times on or after the Initial Exercise Date and on or before the Termination Date by (1) delivery to the Company of a duly executed facsimile copy of the Notice of Exercise Form annexed hereto (or such other office or agency of the Company as it may designate by notice in writing to the registered Holder at the address of the Holder appearing on the books of the Company); provided , however , within 5 Trading Days of the date said Notice of Exercise is delivered to the Company, if this Warrant is exercised in full, the Holder shall have surrendered this Warrant to the Company and (2) the Company shall have received payment of the aggregate Exercise Price of the shares thereby purchased by wire transfer or cashier’s check drawn on a United States bank. Notwithstanding anything herein to the contrary, the Holder shall not be required to physically surrender this Warrant to the Company until the Holder has purchased all of the Warrant Shares available hereunder and the Warrant has been exercised in full. Partial exercises of this Warrant resulting in purchases of a portion of the total number of Warrant Shares available hereunder shall have the effect of lowering the outstanding number of Warrant Shares purchasable hereunder in an amount equal to the applicable number of Warrant Shares purchased. The Holder and the Company shall maintain records showing the number of Warrant Shares purchased and the date of such purchases. The Company shall deliver any objection to any Notice of Exercise Form within 1 Business Day of receipt of such notice. In the event of any dispute or discrepancy, the records of the Holder shall be controlling and determinative in

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the absence of manifest error. The Holder and any assignee, by acceptance of this Warrant, acknowledge and agree that, by reason of the provisions of this paragraph, following the purchase of a portion of the Warrant Shares hereunder, the number of Warrant Shares available for purchase hereunder at any given time may be less than the amount stated on the face hereof .

b) Exercise Price . The exercise price per share of the Common Stock under this Warrant shall be $1.40, subject to adjustment hereunder (the “ Exercise Price ”).

c) Cashless Exercise . If at the time of exercise hereof there is no effective registration statement registering (or the prospectus contained therein is not available for) the issuance of the Warrant Shares to the Holder and also at such time of exercise all of the Warrant Shares are not then registered for resale by the Holder into the market at market prices from time to time on an effective registration statement for use on a continuous basis (or the prospectus contained therein is not available for use), then this Warrant may also be exercised at such time by means of a “cashless exercise” in which the Holder shall be entitled to receive a certificate for the number of Warrant Shares equal to the quotient obtained by dividing [(A-B) (X)] by (A), where:

“ VWAP ” means, for any date, the price determined by the first of the following clauses that applies: (a) if the Common Stock is then listed or quoted on a Trading Market, the daily volume weighted average price of the Common Stock for such date (or the nearest preceding date) on the Trading Market on which the Common Stock is then listed or quoted for trading as reported by Bloomberg L.P. (based on a Trading Day from 9:30 a.m. (New York City time) to 4:02 p.m. (New York City time)); (b) if the Common Stock is then listed or quoted on the OTC Bulletin Board and the OTC Bulletin Board is not a Trading Market, the volume weighted average price of the Common Stock for such date (or the nearest preceding date) on the OTC Bulletin Board; (c) if the Common Stock is not then quoted for trading on the OTC Bulletin Board and if prices for the Common Stock are then reported in the “Pink Sheets” published by Pink OTC Markets, Inc. (or a similar organization or agency succeeding to its functions of reporting prices), the most recent bid price per share of the Common Stock so reported; or (d) in all other cases, the fair market value of a share of Common Stock as determined by an independent appraiser selected in good faith by the Holder and reasonably acceptable to the Company, the fees and expenses of which shall be paid by the Company.

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d) Holder’s Restrictions . Notwithstanding anything to the contrary contained in this Warrant, this Warrant shall not be exercisable by the Holder hereof to the extent (but only to the extent) that the Holder or any of its affiliates would beneficially own in excess of 9.99% (the “ Maximum Percentage ”) of the Common Stock. To the extent the above limitation applies, the determination of whether this Warrant shall be exercisable (vis-à-vis other convertible, exercisable or exchangeable securities owned by the Holder) and of which warrants shall be exercisable (as among all warrants owned by the Holder) shall, subject to such Maximum Percentage limitation, be determined on the basis of the first submission to the Company for conversion, exercise or exchange (as the case may be). No prior inability to exercise this Warrant pursuant to this paragraph shall have any effect on the applicability of the provisions of this paragraph with respect to any subsequent determination of exercisability. For the purposes of this paragraph, beneficial ownership and all determinations and calculations (including, without limitation, with respect to calculations of percentage ownership) shall be determined in accordance with Section 13(d) of the Exchange Act (as defined in the Purchase Agreement) and the rules and regulations promulgated thereunder. The provisions of this paragraph shall be implemented in a manner otherwise than in strict conformity with the terms of this paragraph to correct this paragraph (or any portion hereof) which may be defective or inconsistent with the intended Maximum Percentage beneficial ownership limitation herein contained or to make changes or supplements necessary or desirable to properly give effect to such Maximum Percentage limitation. The limitations contained in this paragraph shall apply to a successor Holder of this Warrant. The holders of Common Stock shall be third party beneficiaries of this paragraph and the Company may not waive this paragraph without the consent of holders of a majority of its Common Stock. For any reason at any time, upon the written or oral request of the Holder, the Company shall within one (1) Business Day confirm orally and in writing to the Holder the number of shares of Common Stock then outstanding, including by virtue of any prior conversion or exercise of convertible or exercisable securities into Common Stock, including, without limitation, pursuant to this Warrant or securities issued pursuant to the Purchase Agreement.

e) Mechanics of Exercise .

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

ii. Delivery of Certificates Upon Exercise . Certificates representing Warrant Shares shall be transmitted by the transfer agent of the Company to the Holder by crediting the account of the Holder’s prime broker with the Depository Trust Company through its Deposit Withdrawal Agent Commission (“ DWAC ”) system if the Company is a participant in such system and either (A) there is an effective Registration Statement permitting the issuance of the Warrant Shares to or resale of the Warrant Shares by the Holder or (B) this Warrant is being exercised, after the first anniversary of the issuance of this Warrant, via cashless

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exercise, and otherwise by physical delivery to the address specified by the Holder in the Notice of Exercise within 3 Business Days from the delivery to the Company of the Notice of Exercise Form, surrender of this Warrant (if required) and payment of the aggregate Exercise Price as set forth above (including, by cashless exercise, if permitted) (“ Warrant Share Delivery Date ”). If all or any portion of a Warrant is exercised at a time when there is an effective registration statement to cover the issuance or resale of the Warrant Shares or if the legend is not required under applicable securities laws, such Warrant Shares shall be issued free of all legends on or before the Warrant Share Delivery Date. This Warrant shall be deemed to have been exercised on the first date on which the Notice of Exercise Form has been delivered to the Company, the Company has received the Exercise Price (or documentation of cashless exercise, if permitted) and all taxes required to be paid by the Holder, if any, pursuant to Section 2(e)(vii) before the issuance of such shares have been paid. The Warrant Shares shall be deemed to have been issued, and Holder or any other person so designated to be named therein shall be deemed to have become a holder of record of such shares for all purposes, on the first date on which the Notice of Exercise Form has been delivered to the Company, the Company has received the Exercise Price (or documentation of cashless exercise, if permitted) and all taxes required to be paid by the Holder, if any, pursuant to Section 2(e)(vii) before the issuance of such shares have been paid.

iii. Delivery of New Warrants Upon Exercise . If this Warrant shall have been exercised in part, the Company shall, at the request of a Holder and upon surrender of this Warrant certificate, at the time of delivery of the certificate or certificates representing Warrant Shares, deliver to Holder a new Warrant evidencing the rights of Holder to purchase the unpurchased Warrant Shares called for by this Warrant, which new Warrant shall in all other respects be identical with this Warrant.

iv. Rescission Rights . If the Company fails to cause its transfer agent to transmit to the Holder a certificate or certificates representing the Warrant Shares pursuant to Section 2 by the Warrant Share Delivery Date, then the Holder will have the right to rescind such exercise.

v. Compensation for Buy-In on Failure to Timely Deliver Certificates Upon Exercise . In addition to any other rights available to the Holder, if the Company fails to cause its transfer agent to transmit to the Holder a certificate or certificates representing the Warrant Shares pursuant to an exercise on or before the Warrant Share Delivery Date pursuant to this Section 2(e), and if after such date the Holder is required by its broker to purchase (in an open market transaction or otherwise) shares of Common Stock to deliver in satisfaction of a sale by the Holder of the Warrant Shares which the Holder anticipated receiving upon such exercise (a “ Buy-In” ), then the Company shall (1) pay in cash to the Holder the amount by which (x) the Holder’s total purchase price (including brokerage commissions, if any) for the shares of Common Stock so purchased exceeds (y) the amount obtained by multiplying (A) the number of Warrant

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Shares that the Company was required to deliver to the Holder in connection with the exercise at issue times (B) the price at which the sell order giving rise to such purchase obligation was executed, and (2) at the option of the Holder, either reinstate the portion of the Warrant and equivalent number of Warrant Shares for which such exercise was not honored or deliver to the Holder the number of shares of Common Stock that would have been issued had the Company timely complied with its exercise and delivery obligations hereunder. For example, if the Holder purchases Common Stock having a total purchase price of $11,000 to cover a Buy-In with respect to an attempted exercise of shares of Common Stock with an aggregate sale price giving rise to such purchase obligation of $10,000, under clause (1) of the immediately preceding sentence the Company shall be required to pay the Holder $1,000. The Holder shall provide the Company written notice indicating the amounts payable to the Holder in respect of the Buy-In, together with applicable confirmations and other evidence reasonably requested by the Company. Nothing herein shall limit a Holder’s right to pursue any other remedies available to it hereunder, at law or in equity including, without limitation, a decree of specific performance and/or injunctive relief with respect to the Company’s failure to timely deliver certificates representing shares of Common Stock upon exercise of the Warrant as required pursuant to the terms hereof.

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

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

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

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