Document:

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                                                                     EXHIBIT 4.4

                               BIOPURE CORPORATION

                                 AGENT'S WARRANT

Warrant No. [_____]                                       Dated: August 10, 2005

      Biopure Corporation, a Delaware corporation (the "COMPANY"), hereby
certifies that, for value received, [_____________] or their registered assigns
(including permitted transferees, the "HOLDER"), is entitled to purchase from
the Company 50,000 shares (as adjusted from time to time as provided in Section
9) of Common Stock (as defined below), together with the associated preferred
stock purchase rights under that certain Rights Agreement (the "RIGHTS
AGREEMENT") dated as of as of September 24, 1999 between the Company and
American Stock Transfer & Trust Company, as rights agent, to the extent the
Rights Agreement is in effect on the date of such purchase, at an exercise price
equal to $1.43 per share (as adjusted from time to time as provided in Section
9, the "EXERCISE PRICE"), at any time and from time to time from and after
January 29, 2006 (the "INITIAL EXERCISE DATE") to and including January 28, 2008
(the "EXPIRATION DATE"), and subject to the following terms and conditions.

      1. Definitions. The capitalized terms used herein and not otherwise
defined shall have the meanings set forth below:

            "AFFILIATE" of any specified Person means any other person or entity
directly or indirectly controlling, controlled by or under direct or indirect
common control with such specified Person. For purposes of this definition,
"CONTROL" means the power to direct the management and policies of such Person
or firm, directly or indirectly, whether through the ownership of voting
securities, by contract or otherwise.

            "COMMISSION" means the United States Securities and Exchange
Commission.

            "COMMON STOCK" means the Class A common stock of the Company, $0.01
par value per share.

            "ELIGIBLE MARKET" means any of the New York Stock Exchange, the
American Stock Exchange or Nasdaq, and any successor markets thereto.

            "EXCHANGE ACT" means the Securities Exchange Act of 1934, as amended

            "MARKET PRICE" shall mean (i) if the principal trading market for
such securities is an exchange, the average of the last reported sale prices per
share for the last ten previous Trading Days in which a sale was reported, as
officially reported on any consolidated tape, (ii) if clause (i) is not
applicable, the average of the closing bid price per share for the last ten
previous Trading Days as set forth by Nasdaq or (iii) if clauses (i) and (ii)
are not applicable, the average

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of the closing bid price per share for the last ten previous Trading Days as set
forth in the National Quotation Bureau sheet listing for such securities.
Notwithstanding the foregoing, if there is no reported sales price or closing
bid price, as the case may be, on any of the ten Trading Days preceding the
event requiring a determination of Market Price hereunder, then the Market Price
shall be determined in good faith after reasonable investigation by resolution
of the Board of Directors of the Company.

            "NASDAQ" means the Nasdaq SmallCap Market or Nasdaq National Market,
and any successor markets thereto.

            "OTHER SECURITIES" refers to any capital stock (other than Common
Stock) and other securities of the Company or any other Person which the Holder
of this Warrant at any time shall be entitled to receive, or shall have
received, pursuant to the terms hereof upon the exercise of this Warrant, in
lieu of or in addition to Common Stock.

            "PERSON" means any court or other federal, state, local or other
governmental authority or other individual or corporation, partnership, trust,
incorporated or unincorporated association, joint venture, limited liability
company, joint stock company, government (or an agency or subdivision thereof)
or other entity of any kind.

            "REGISTRATION STATEMENT" means the Company's Registration Statement
on Form S-3 filed with the Commission on June 19, 2003, as such registration
statement is amended or supplemented.

            "TRADING DAY" means (a) any day on which the Common Stock is listed
or quoted and traded on any Eligible Market or (b) if the Common Stock is not
then quoted and traded on any Eligible Market, then a day on which trading
occurs on the Nasdaq National Market (or any successor thereto).

            "WARRANT SHARES" shall initially mean shares of Common Stock
(together with the associated preferred stock purchase rights under the Rights
Agreement to the extent the Rights Agreement is in effect on the applicable
date) and in addition may include Other Securities and Substituted Property (as
defined in Section 9(e)(x)) issued or issuable from time to time upon exercise
of this Warrant.

      2. Registration of Warrant. The Company shall register this Warrant, upon
records to be maintained by the Company for that purpose (the "WARRANT
REGISTER"), in the name of the record Holder hereof from time to time. The
Company may deem and treat the registered Holder of this Warrant as the absolute
owner hereof for the purpose of any exercise hereof or any distribution to the
Holder, and for all other purposes.

      3. Registration of Transfers. The Company shall register the transfer of
any portion of this Warrant in the Warrant Register, upon surrender of this
Warrant, with the Form of Assignment attached hereto as Appendix A duly
completed and signed, to the Company at its address specified herein. Upon any
such registration and transfer, a new warrant in substantially the form of a
Warrant (any such new warrant, a "NEW WARRANT"), evidencing the portion of this
Warrant so transferred shall be issued to the transferee and a New Warrant
evidencing the remaining portion of this Warrant not so transferred, if any,
shall be issued to the transferring Holder. The acceptance of the New Warrant by
the transferee thereof shall be deemed the acceptance by such transferee of all
of the rights and obligations of a holder of a Warrant.

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      4. Exercise and Duration of Warrant.

            (a) This Warrant shall be exercisable, either in its entirety or for
a portion of the number of Warrant Shares, by the registered Holder at any time
and from time to time from and after the Initial Exercise Date to and including
the Expiration Date. At 5:00 P.M. New York City time on the Expiration Date, the
portion of this Warrant not exercised prior thereto shall be and become void and
of no value, and the Holder hereof shall have no right to purchase any
additional Warrant Shares hereunder.

            (b) A Holder may exercise this Warrant by delivering to the Company,
in accordance with Section 13, this Warrant, together with (i) an exercise
notice, in the form attached hereto as Appendix B (the "EXERCISE NOTICE"),
appropriately completed and duly signed, and (ii) payment of the Exercise Price
for the number of Warrant Shares as to which this Warrant is being exercised (as
set forth in Section 4(c) below), and the date such items are received by the
Company is an "EXERCISE DATE." Execution and delivery of an Exercise Notice in
respect of less than all of the Warrant Shares issuable upon exercise of this
Warrant shall result in the cancellation of the original Warrant and issuance of
a New Warrant evidencing the right to purchase the remaining number of Warrant
Shares.

            (c) The Holder shall pay the Exercise Price in cash, by certified
bank check payable to the order of the Company or by wire transfer of
immediately available funds in accordance with the Company's instructions.

            (d) Except as otherwise provided for herein, this Warrant shall not
entitle the Holder to any voting rights or other rights as a stockholder of the
Company by virtue of the ownership hereof.

      5. Delivery of Warrant Shares.

            (a) Upon exercise of this Warrant, the Company shall promptly, issue
or cause to be issued and deliver or cause to be delivered to the Holder, in
such name or names as the Holder may designate, a certificate for the Warrant
Shares issuable upon such exercise (the "CERTIFICATE") bearing no restrictive
legends. The Holder, or any Person so designated by the Holder to receive the
Warrant Shares, shall be deemed to have become holder of record of such Warrant
Shares as of the Exercise Date. Failure by the Company to deliver the
Certificate (or to instruct DTC to credit the Holder's balance account with DTC
for the Warrant Shares issuable upon such exercise) on or before the tenth day
following the Exercise Date (the "OUTSIDE DATE") shall entitle the Holder to an
amount in cash from the Company for each Trading Day following the Outside Date
until the delivery is effected equal to 1.0% of the product of (i) the Warrant
Shares issuable upon such exercise and (ii) the positive difference between the
Market Price on the Outside Date and the Exercise Price.

            (b) The Warrant and the Warrant Shares will be registered pursuant
to the Registration Statement, and the Company covenants and agrees to maintain
the effectiveness of the Registration Statement until the earlier of (i) such
time as the Warrant Shares have been sold thereunder or (ii) one hundred and
eighty (180) days following the exercise in full of the Warrant or the
expiration of any Warrant Shares not previously exercised thereunder.
Notwithstanding the foregoing, in the event that, prior to such time as all of
the Warrant Shares have been sold by the Holder, the Company ceases to be
eligible under the Securities Act of 1933, as amended (the

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"ACT") or the rules and regulations promulgated thereunder, to maintain a
registration statement on Form S-3, or in the event that the Warrant or the
Warrant Shares cease to be eligible for inclusion in such Registration Statement
to the extent necessary to permit the Holder to exercise the Warrant and sell
the Warrant Shares without restriction under the Act, the Company will promptly
(and in any event within 10 days of the date that the Warrant or any Warrant
Shares cease to be so eligible), amend or file a new registration statement
under the Act on a form eligible for use by the Company for the registration of
such securities and use its best efforts to have such registration statement
declared effective by the Commission as soon as practicable after such filing,
which registration statement shall include such information as may be required
to permit the exercise of the Warrant and the sale of the Warrant Shares without
restriction under the Act. The Holder acknowledges and agrees that the Warrant
shall be exercisable pursuant to any such registration statement only at such
times as the registration statement is effective or in accordance with any
applicable exemption from the registration requirements of the Act. During such
time as the Warrant Shares are registered pursuant to any registration statement
under the Act, the Company further covenants and agrees to make timely filings
of all documents required by be filed under the Act or the Exchange Act in order
to ensure that the registration statement, including the documents incorporated
by reference therein, if any, do not contain an untrue statement of a material
fact or omit to state any material fact required to be stated therein or
necessary in order to make the statements therein not misleading.

            (c) This Warrant is exercisable, either in its entirety or, from
time to time, for a portion of the number of Warrant Shares. Upon surrender of
this Warrant following one or more partial exercises, the Company shall issue or
cause to be issued, at its expense, a New Warrant evidencing the right to
purchase the remaining number of Warrant Shares.

      6. Charges, Taxes and Expenses. Issuance and delivery of certificates for
shares of Common Stock upon exercise of this Warrant shall be made without
charge to the Holder for any issue or transfer tax, withholding tax, transfer
agent fee or other incidental tax or expense in respect of the issuance of such
certificates, all of which taxes and expenses shall be paid by the Company;
provided, however, that the Company shall not be required to pay any tax which
may be payable in respect of any transfer involved in the issue, delivery or
registration of any certificates for Warrant Shares or Warrant in a name other
than that of the Holder and that the Holder will be required to pay any tax with
respect to cash received in lieu of fractional shares. The Holder shall be
responsible for all other tax liability that may arise as a result of holding or
transferring this Warrant or receiving Warrant Shares upon exercise hereof.

      7. Replacement of Warrant. If this Warrant is mutilated, lost, stolen or
destroyed, the Company, at the sole expense of the Holder (such expenses, if any
imposed by the Company to be reasonable), shall issue or cause to be issued in
exchange and substitution for and upon cancellation hereof, or in lieu of and in
substitution for this Warrant, a New Warrant, but only upon receipt of evidence
reasonably satisfactory to the Company of such loss, theft or destruction and
customary and reasonable indemnity, if requested by the Company.

      8. Reservation of Warrant Shares. The Company covenants that it will at
all times reserve and keep available out of the aggregate of its authorized but
unissued and otherwise unreserved Common Stock, solely for the purpose of
enabling it to issue Warrant Shares upon exercise of this Warrant as herein
provided, the number of Warrant Shares which are then issuable and deliverable
upon the exercise of this entire Warrant, free from all taxes, liens, claims,
encumbrances with respect to the issuance of such Warrant Shares and will not be
subject to any pre-emptive rights or similar rights (taking into account the
adjustments and restrictions of

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Section 9 hereof). The Company covenants that all Warrant Shares so issuable and
deliverable shall, upon issuance and the payment of the applicable Exercise
Price in accordance with the terms hereof, be duly and validly authorized,
issued, fully paid and nonassessable. The Company will take all such action as
may be necessary to assure that such shares of Common Stock may be issued as
provided herein without violation of any applicable law or regulation, or of any
requirements of any securities exchange or automated quotation system upon which
the Common Stock may be listed or quoted, as the case may be; provided, however,
that such actions shall only require the Company's best efforts (or other
specified standard) to the extent specifically provided for in this Warrant.

      9. Certain Adjustments. The Exercise Price and number of Warrant Shares
issuable upon exercise of this Warrant are subject to adjustment from time to
time as set forth in this Section 9.

            (a) Stock Dividends. If the Company, at any time while this Warrant
is outstanding, pays a dividend on its Common Stock payable in additional shares
of Common Stock or otherwise makes a distribution on any class of capital stock
that is payable in shares of Common Stock, then in each such case the Exercise
Price shall be multiplied by a fraction, (A) the numerator of which shall be the
number of shares of Common Stock outstanding immediately prior to the opening of
business on the day after the record date for the determination of stockholders
entitled to receive such dividend or distribution and (B) the denominator of
which shall be the number of shares of Common Stock outstanding immediately
after the distribution date of such dividend or distribution. Any adjustment
made pursuant to this Section 9(a) shall become effective immediately after the
record date for the determination of stockholders entitled to receive such
dividend or distribution; provided, however, that if following such record date
the Company rescinds or modifies such dividend or distribution, the Exercise
Price shall be appropriately adjusted (as of the date that the Company
effectively rescinds or modifies such dividend or distribution) to take into
account the effect of such rescinded or modified dividend or distribution on the
Exercise Price pursuant to this Section 9(a).

            (b) Stock Splits. If the Company, at any time while this Warrant is
outstanding, (i) subdivides outstanding shares of Common Stock into a larger
number of shares, or (ii) combines outstanding shares of Common Stock into a
smaller number of shares, then in each such case the Exercise Price shall be
multiplied by a fraction, (A) the numerator of which shall be the number of
shares of Common Stock outstanding immediately before such event and (B) the
denominator of which shall be the number of shares of Common Stock outstanding
immediately after such event. Any adjustment pursuant to this Section 9(b) shall
become effective immediately after the effective date of such subdivision or
combination.

            (c) Reclassifications. A reclassification of the Common Stock (other
than any such reclassification in connection with a merger or consolidation to
which Section 9(e) applies) into shares of any other class of stock shall be
deemed:

                  (i) a distribution by the Company to the holders of its Common
Stock of such shares of such other class of stock for the purposes and within
the meaning of this Section 9; and

                  (ii) if the outstanding shares of Common Stock shall be
changed into a larger or smaller number of shares of Common Stock as part of
such reclassification, such change shall be deemed a subdivision or combination,
as the case may be, of the outstanding

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shares of Common Stock for the purposes and within the meaning of Section 9(b).

            (d) Other Distributions. If the Company, at any time while this
Warrant is outstanding, distributes to holders of Common Stock (i) evidences of
its indebtedness, (ii) shares of any class of capital stock, (iii) rights or
warrants to subscribe for or purchase any shares of any class of capital stock
or (iv) any other asset, other than a distribution of Common Stock covered by
Section 9(a), (in each case, "DISTRIBUTED PROPERTY"), then in each such case the
Exercise Price in effect immediately prior to the record date fixed for
determination of stockholders entitled to receive such distribution (and the
Exercise Price thereafter applicable) shall be adjusted (effective on and after
such record date) to equal the product of such Exercise Price multiplied by a
fraction, (A) the numerator of which shall be Market Price on such record date
less the then fair market value of the Distributed Property distributed in
respect of one outstanding share of Common Stock, which, if the Distributed
Property is other than cash or marketable securities, shall be as determined in
good faith by the Board of Directors of the Company whose determination shall be
described in a board resolution, and (B) the denominator of which shall be the
Market Price on such record date; provided, however, that if following the
record date for such distribution the Company rescinds or modifies such
distribution, the Exercise Price shall be appropriately adjusted (as of the date
that the Company effectively rescinds or modifies such distribution) to take
into account the effect of such rescinded or modified distribution on the
Exercise Price pursuant to this Section 9(d).

            (e) Fundamental Transactions. If, at any time following the Initial
Exercise Date, (i) the Company effects any merger or consolidation of the
Company with or into another Person, (ii) the Company effects any sale of all or
substantially all of its assets in one or a series of related transactions or
(iii) there shall occur any merger of another Person into the Company whereby
the Common Stock is cancelled, converted or reclassified into or exchanged for
other securities, cash or property (in any such case, a "FUNDAMENTAL
TRANSACTION"), then, as a condition to the consummation of such Fundamental
Transaction, the Company shall (or, in the case of any Fundamental Transaction
in which the Company is not the surviving entity, the Company shall take all
reasonable steps to cause such other Person to) execute and deliver to the
Holder of this Warrant a written instrument providing that:

                  (x) so long as this Warrant remains outstanding, upon the
exercise hereof at any time on or after the consummation of such Fundamental
Transaction and on such terms and subject to such conditions as shall be nearly
equivalent as may be practicable to the provisions set forth in this Warrant,
this Warrant shall be exercisable into, in lieu of Common Stock issuable upon
such exercise prior to such consummation, the securities or other property (the
"SUBSTITUTED PROPERTY") that would have been received in connection with such
Fundamental Transaction by a holder of the number of shares of Common Stock into
which this Warrant was exercisable immediately prior to such Fundamental
Transaction, assuming such holder of Common Stock:

                        (A) is not a Person with which the Company consolidated
or into which the Company merged or which merged into the Company or to which
such sale or transfer was made, as the case may be (a "CONSTITUENT PERSON"), or
an Affiliate of a Constituent Person; and

                        (B) failed to exercise such Holder's rights of election,
if any, as to the kind or amount of securities, cash and other property
receivable in connection with such Fundamental Transaction (provided, however,
that if the kind or amount of securities, cash or

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other property receivable in connection with such Fundamental Transaction is not
the same for each share of Common Stock held immediately prior to such
Fundamental Transaction by a Person other than a Constituent Person or an
Affiliate thereof and in respect of which such rights of election shall not have
been exercised (a "NON-ELECTING SHARE"), then, for the purposes of this Section
9(e), the kind and amount of securities, cash and other property receivable in
connection with such Fundamental Transaction by each Non-Electing Share shall be
deemed to be the kind and amount so receivable per share by a plurality of the
Non-Electing Shares); and

                  (y) the rights and obligations of the Company (or, in the
event of a transaction in which the Company is not the surviving Person, such
other Person) and the Holder in respect of Substituted Property shall be as
nearly equivalent as may be practicable to the rights and obligations of the
Company and Holder in respect of Common Stock hereunder.

            Such written instrument shall provide for adjustments which, for
events subsequent to the effective date of such written instrument, shall be as
nearly equivalent as may be practicable to the adjustments provided for in this
Section 9. The above provisions of this Section 9(e) shall similarly apply to
successive Fundamental Transactions.

            (f) Adjustment of Warrant Shares. Simultaneously with any adjustment
to the Exercise Price pursuant to paragraphs (a) through (d) of this Section 9,
the number of Warrant Shares that may be purchased upon exercise of this Warrant
shall be increased or decreased proportionately, so that after such adjustment
the aggregate Exercise Price payable hereunder for the increased or decreased
number of Warrant Shares shall be the same as the aggregate Exercise Price
payable for the Warrant Shares immediately prior to such adjustment.

            (g) Calculations. All calculations under this Section 9 shall be
made to the nearest cent or the nearest 1/100th of a share, as applicable. The
number of shares of Common Stock outstanding at any given time shall not include
shares owned or held by or for the account of the Company, and the disposition
of any such shares shall be considered an issue or sale of Common Stock.

            (h) Adjustments. Notwithstanding any provision of this Section 9, no
adjustment of the Exercise Price shall be required if such adjustment is less
than $0.01; provided, however, that any adjustments which by reason of this
Section 9(h) are not required to be made shall be carried forward and taken into
account for purposes of any subsequent adjustment required to be made hereunder.

            (i) Notice of Adjustments. Upon the occurrence of each adjustment
pursuant to this Section 9, the Company will promptly deliver to the Holder a
certificate executed by the Company's Chief Financial Officer setting forth, in
reasonable detail, the event requiring such adjustment and the method by which
such adjustment was calculated, the adjusted Exercise Price and the adjusted
number or type of Warrant Shares or other securities issuable upon exercise of
this Warrant (as applicable). The Company will retain at its office copies of
all such certificates and cause the same to be available for inspection at said
office during normal business hours by the Holder or any prospective purchaser
of the Warrant designated by the Holder.

            (j) Notice of Corporate Events. If the Company (i) declares a
dividend or any other distribution of cash, securities or other property in
respect of its Common Stock, including, without limitation, any granting of
rights or warrants to subscribe for or purchase any capital stock of the Company
or any subsidiary of the Company, (ii) authorizes, approves, enters into

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any agreement contemplating, or solicits stockholder approval for, any
Fundamental Transaction or (iii) authorizes the voluntary dissolution,
liquidation or winding up of the affairs of the Company, then the Company shall
deliver to the Holder a notice describing the material terms and conditions of
such transaction at least 15 calendar days prior to the applicable record or
effective date on which a Person would need to hold Common Stock in order to
participate in or vote with respect to such transaction, and the Company will
take all steps reasonably necessary in order to ensure that the Holder is given
the practical opportunity to exercise this Warrant prior to such time so as to
participate in or vote with respect to such transaction; provided, however, that
the failure to deliver such notice or any defect therein shall not affect the
validity of the corporate action required to be described in such notice.

      10. Fractional Shares. The Company shall not be required to issue or cause
to be issued fractional Warrant Shares on the exercise of this Warrant. If any
fraction of a Warrant Share would, except for the provisions of this Section 10,
be issuable upon exercise of this Warrant, the Company shall make a cash payment
to the Holder equal to (a) such fraction multiplied by (b) the Market Price on
the Exercise Date of one full Warrant Share.

      11. Listing on Securities Exchanges. The Company has listed, and will use
its best efforts to maintain the listing of, the Warrant Shares on Nasdaq. In
furtherance and not in limitation of any other provision of this Warrant, if the
Company at any time shall list any Common Stock on any Eligible Market other
than Nasdaq, the Company will, at its expense, simultaneously list the Warrant
Shares (and use its best efforts to maintain such listing) on such Eligible
Market, upon official notice of issuance following the exercise of this Warrant;
and the Company will so list, register and use its best efforts to maintain such
listing on any Eligible Market any Other Securities, if and at the time that any
securities of like class or similar type shall be listed on such Eligible Market
by the Company.

      12. Remedies. The Company stipulates that the remedies at law of the
Holder of this Warrant in the event of any default or threatened default by the
Company in the performance of or compliance with any of the terms of this
Warrant are not and will not be adequate, and that such terms may be
specifically enforced by a decree for the specific performance of any agreement
contained herein or by an injunction against a violation of any of the terms
hereof or otherwise.

      13. Notices. Any and all notices or other communications or deliveries
hereunder (including without limitation any Exercise Notice) shall be in writing
and shall be mailed by certified mail, return receipt requested, or by a
nationally recognized courier service or delivered (in person or by facsimile),
against receipt to the party to whom such notice or other communication is to be
given. Any notice or other communication given by means permitted by this
Section 13 shall be deemed given at the time of receipt thereof. The address for
such notices or communications shall be as set forth below:

      If to the Company:      Biopure Corporation
                              11 Hurley Street
                              Cambridge, MA  02141

      If to the Holder:       [___________]

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Or such other address as is provided to such other party in accordance with this
Section 14.

      14. Warrant Agent. The Company shall serve as warrant agent under this
Warrant. Upon 30 days' notice to the Holder, the Company may appoint a new
warrant agent. Any Person into which any new warrant agent may be merged, any
Person resulting from any consolidation to which any new warrant agent shall be
a party or any Person to which any new warrant agent transfers substantially all
of its corporate trust or shareholders services business shall be a successor
warrant agent under this Warrant without any further act. Any such successor
warrant agent shall promptly cause notice of its succession as warrant agent to
be mailed (by first class mail, postage prepaid) to the Holder at the Holder's
last address as shown on the Warrant Register.

      15. Miscellaneous. (a) This Warrant may be assigned by the Holder. This
Warrant may not be assigned by the Company, except to a successor in the event
of a Fundamental Transaction. This Warrant shall be binding on and inure to the
benefit of the parties hereto and their respective successors and assigns.
Subject to the preceding sentence, nothing in this Warrant shall be construed to
give to any Person other than the Company and the Holder any legal or equitable
right, remedy or cause of action under this Warrant. This Warrant may be amended
only in writing signed by the Company and the Holder and their successors and
assigns.

            (b) The Company will not, by amendment of its governing documents or
through any reorganization, transfer of assets, consolidation, merger,
dissolution, issue or sale of securities or any other voluntary action, avoid or
seek to avoid the observance or performance of any of the terms of this Warrant,
but will at all times in good faith assist in the carrying out of all such terms
and in the taking of all such action as may be necessary or appropriate in order
to protect the rights of the Holder against impairment. Without limiting the
generality of the foregoing, the Company (i) will not increase the par value of
any Warrant Shares above the amount payable therefor upon exercise thereof, and
(ii) will take all such action as may be reasonably necessary or appropriate in
order that the Company may validly and legally issue fully paid and
nonassessable Warrant Shares on the exercise of this Warrant, free from all
taxes, liens, claims and encumbrances and (iii) will not close its shareholder
books or records in any manner which interferes with the timely exercise of this
Warrant.

            (c) This Warrant shall be governed by and construed and enforced in
accordance with the laws of the State of New York. Each party hereby irrevocably
submits to the exclusive jurisdiction of the state and Federal courts sitting in
the City of New York, Borough of Manhattan, for the adjudication of any dispute
hereunder or in connection herewith or with any transaction contemplated hereby
or discussed herein, and hereby irrevocably waives, and agrees not to assert in
any suit, action or proceeding that it is not personally subject to the
jurisdiction of any such court or that such suit, action or proceeding is
improper. Each party hereby irrevocably waives personal service of process and
consents to process being served in any such suit, action or proceeding by
mailing a copy thereof via registered or certified mail or overnight delivery
(with evidence of delivery) to such party at the address in effect for notices
to it under this Warrant and agrees that such service shall constitute good and
sufficient service of process and notice thereof. Nothing contained herein shall
be deemed to limit in any way any right to serve process in any manner permitted
by law. THE PARTIES HEREBY WAIVE ALL RIGHTS TO A TRIAL BY JURY.

            (d) Neither party shall be deemed in default of any provision of
this Warrant, to

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the extent that performance of its obligations or attempts to cure a breach
hereof are delayed or prevented by any event reasonably beyond the control of
such party, including, without limitation, war, hostilities, acts of terrorism,
revolution, riot, civil commotion, national emergency, strike, lockout,
unavailability of supplies, epidemic, fire, flood, earthquake, force of nature,
explosion, embargo, or any other Act of God, or any law, proclamation,
regulation, ordinance, or other act or order of any court, government or
governmental agency, provided that such party gives the other party written
notice thereof promptly upon discovery thereof and uses reasonable efforts to
cure or mitigate the delay or failure to perform.

            (e) The headings herein are for convenience only, do not constitute
a part of this Warrant and shall not be deemed to limit or affect any of the
provisions hereof.

            (f) In case any one or more of the provisions of this Warrant shall
be deemed invalid or unenforceable in any respect, the validity and
enforceability of the remaining terms and provisions of this Warrant shall not
in any way be affected or impaired thereby and the parties will attempt in good
faith to agree upon a valid and enforceable provision which shall be a
commercially reasonable substitute therefor, and upon so agreeing, shall
incorporate such substitute provision in this Warrant.

                  [REMAINDER OF PAGE INTENTIONALLY LEFT BLANK,
                             SIGNATURE PAGE FOLLOWS]

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            IN WITNESS WHEREOF, the Company has caused this Warrant to be duly
executed by its authorized officer as of the date first indicated above.

                                      BIOPURE CORPORATION

                                      By:_______________________________________
                                         Name:
                                         Title:

<PAGE>

                                   APPENDIX A

                               FORM OF ASSIGNMENT

           (to be completed and signed only upon transfer of Warrant)

            FOR VALUE RECEIVED, the undersigned hereby sells, assigns and
transfers unto ____________________ the right represented by the within Warrant
to purchase _____________ shares of Common Stock of Biopure Corporation to which
the within warrant relates and appoints __________________________ attorney to
transfer said right on the books of Biopure Corporation with full power of
substitution in the premises.

Dated:____________                       _______________________________________
                                         (Signature must conform in all respects
                                         to name of Holder as specified on face
                                         of the Warrant)

                                         Address of Transferee:

                                         _______________________________

                                         _______________________________

                                         _______________________________

In the presence of:

_________________________________

<PAGE>

                                   APPENDIX B

                             FORM OF EXERCISE NOTICE

(To be executed by the Holder to exercise the right to purchase shares of Common
Stock under the foregoing Warrant)

To:   Biopure Corporation

The undersigned is the Holder of Warrant No. [    ] (the "Warrant") issued by
Biopure Corporation, a Delaware corporation (the "Company"). Capitalized terms
used herein and not otherwise defined have the respective meanings set forth in
the Warrant.

1.    The Warrant is currently exercisable to purchase a total of _________
      Warrant Shares.

2.    The undersigned Holder hereby exercises its right to purchase _________
      Warrant Shares pursuant to the Warrant.

3.    The Holder shall pay the sum of $________ to the Company in accordance
      with the terms of the Warrant.

4.    Pursuant to this exercise, the Company shall deliver to the Holder Warrant
      Shares in accordance with the terms of the Warrant

5.    Following this exercise, the Warrant shall be exercisable to purchase a
      total of __________ Warrant Shares.

Dated: ____________                     Name of Holder:

                                        (Print)_________________________________

                                        By:_____________________________________

                                        Title:__________________________________

                                        (Signature must conform in all respects
                                        to name of Holder as specified on face
                                        of the Warrant)<PAGE>

                                                                   EXHIBIT 4.10
                               Biopure Corporation
                             STOCK PURCHASE WARRANT

                            Dated: February 19, 2004

      This certifies that [__________________] or its permitted transferee (the
"Holder") is entitled to purchase from BIOPURE CORPORATION, a Delaware
corporation (the "Company"), at the price and during the period as hereinafter
specified, [__________] shares, including associated preferred stock purchase
rights under that certain Rights Agreement (the "Rights Agreement") dated as of
as of September 24, 1999 between the Company and American Stock Transfer & Trust
Company, as Rights Agent (such shares collectively with such associated rights,
the "Shares"), of Class A common stock, $0.01 par value per share, of the
Company (the "Common Stock") at an exercise price of $15.00 per share subject to
adjustment as described below (as so adjusted from time to time, the "Exercise
Price"), at any time during the five-year period commencing on the date hereof.

      1. The rights represented by this Stock Purchase Warrant (this "Warrant")
shall be exercisable during the period as follows:

            (a) At any time and from time to time between the Closing Date and
5:00 PM New York City time on the earlier of (i) the fourth anniversary of the
Closing Date and (ii) the Mandatory Exercise Date (the earlier of such dates,
the "Expiration Date") inclusive, the Holder shall have the right to purchase
Shares hereunder at the Exercise Price.

            (b) After the Expiration Date, the Holder shall have no right to
purchase all or any portion of the Shares hereunder.

      2. The rights represented by the this Warrant may be exercised at any time
within the period above specified, in whole or in part, by (i) the surrender of
this Warrant (with the purchase form at the end hereof properly executed) at the
principal executive office of the Company (or such other office or agency of the
Company as it may designate by notice in writing to the Holder at the address of
the Holder appearing on the books of the Company) and (ii) payment to the
Company of the Exercise Price then in effect for the number of Shares specified
in the above-mentioned purchase form together with applicable stock transfer
taxes, if any. This Warrant shall be deemed to have been exercised, in whole or
in part to the extent specified, immediately prior to the close of business on
the date this Warrant is surrendered and payment is made in accordance with the
foregoing provisions of this Section 2 or Section 4, and the person or persons
in whose name or names the certificates for the Shares shall be issuable upon
such exercise shall become the holder or holders of record of such Shares at
that time and date. The Shares and the certificates for the Shares so purchased
shall be delivered to the Holder within a reasonable time, not exceeding ten
Business Days (as defined below), after the rights represented by this Warrant
shall have been so exercised.

      3. Any transfer of this Warrant shall be effected by the Holder by (i)
executing the form of assignment at the end hereof and (ii) surrendering this
Warrant for cancellation at the office or agency of the Company referred to in
Section 2 hereof, accompanied by a written instrument of transfer in form
reasonably satisfactory to the Company, duly executed by the registered Holder
thereof or by the duly appointed legal representative thereof or by a duly
authorized attorney-in-fact. Upon any transfer of this Warrant or any part
thereof in accordance with the first sentence of this Section 3(a), the Company
shall issue, in the name or names specified by the Holder (including the
Holder), a new Warrant or Warrants of like tenor and representing in the
aggregate rights to purchase the same number of Shares as are purchasable
hereunder at such time. No transfer of this Warrant shall be made in the records
of the Company from and after the date that the Company gives a Mandatory
Exercise Notice pursuant to Section 4.

      4. On any Notification Date (as defined below), the Company may deliver a
written notice to the Holder at the address of the Holder appearing on the books
of the Company (the "Mandatory Exercise

<PAGE>

Notice"). The Mandatory Exercise Notice shall set forth the Closing Price of a
share of Common Stock on each of the ten consecutive Trading Days immediately
preceding the date of the Mandatory Exercise Notice and shall state that this
Warrant must be exercised in conformity with Section 2 on or before a date
specified in the Mandatory Exercise Notice (the "Mandatory Exercise Date"),
which shall be at least twenty Business Days after the date of mailing of the
Mandatory Exercise Notice. If the Holder does not exercise this Warrant in full
on or before the Mandatory Exercise Date, then (i) the Holder shall forfeit such
Holder's rights, title and interest under this Warrant or portion thereof not
exercised, (ii) this Warrant or portion thereof not exercised shall be deemed
terminated, and (iii) the Company may treat this Warrant or portion thereof not
exercised as void for all purposes. "Notification Date" shall mean any Business
Day after February 19, 2006 which is immediately preceded by ten consecutive
Trading Days on each of which the daily volume weighted average price ("VWAP")
for the Common Stock was greater than 200% of the Exercise Price. "Business Day"
shall mean any day, other than a Saturday or a Sunday or a day on which banking
institutions in the State of New York are authorized or obligated by law,
regulation or order to close. "Trading Day" shall mean any day on which the
principal United States securities exchange or trading market on which the
Common Stock is listed or traded (the "Principal Market") as reported by
Bloomberg Financial Markets is open for trading.

      5. The Company covenants and agrees that all Shares which may be purchased
hereunder will, upon issuance and delivery against payment therefore of the
requisite purchase price, be duly and validly issued, fully paid and
nonassessable. Unless otherwise indicated, the Shares so purchased shall be
delivered to the Holder by the Company, which shall cause its transfer agent to
electronically transmit the Shares so purchased to the Holder by crediting the
account of the holder or its nominee with the Depository Trust Company through
its Deposit Withdrawal Agent Commission system. The Company further covenants
and agrees that, during the period within which this Warrant may be exercised,
the Company will at all times have authorized and reserved a sufficient number
of shares of its Common Stock to provide for the exercise of this Warrant.

      6. This Warrant shall not entitle the Holder to any voting rights or other
rights, including without limitation notice of meetings of other actions or
receipt of dividends, as a stockholder of the Company.

      7. The Exercise Price in effect at the time and the number and kind of
securities purchasable upon the exercise of this Warrant shall be subject to
adjustment from time to time upon the happening of certain events as follows:

            (a) In case the Company shall (i) declare a dividend or make a
distribution on its outstanding shares of Common Stock in shares of Common
Stock, (ii) subdivide or reclassify its outstanding shares of Common Stock into
a greater number of shares, (iii) combine or reclassify its outstanding shares
of Common Stock into a smaller number of shares, or (iv) enter into any
transaction whereby the outstanding shares of Common Stock of the Company are at
any time changed into or exchanged for a different number or kind of shares or
other security of the Company or of another corporation through reorganization,
merger, consolidation, liquidation or recapitalization, then appropriate
adjustments in the number of Shares (or other securities for which such Shares
have previously been exchanged or converted) subject to this Warrant shall be
made and the Exercise Price in effect at the time of the record date for such
dividend or distribution or of the effective date of such subdivision,
combination, reclassification, reorganization, merger, consolidation,
liquidation or recapitalization shall be proportionately adjusted so that the
Holder of this Warrant exercised after such date shall be entitled to receive
the aggregate number and kind of shares of Common Stock which, if this Warrant
had been exercised by such Holder immediately prior to such date, the Holder
would have been entitled to receive upon such dividend, distribution,
subdivision, combination, reclassification, reorganization, merger,
consolidation, liquidation or recapitalization. For example, if the Company
declares a 2 for 1 stock distribution and the Exercise Price hereof immediately
prior to such event was $4.00 per Share and the number of Shares issuable upon
exercise of this Warrant was 10,000, the adjusted Exercise Price immediately
after such event would be $2.00 per Share and the adjusted number of Shares
issuable upon exercise of this Warrant would be 20,000. Such adjustment shall be
made successively whenever any event listed above shall occur.

                                       2
<PAGE>

            (b) In case the Company shall fix a record date for the issuance of
rights or warrants to all holders of its Common Stock entitling them to
subscribe for or purchase shares of Common Stock (or securities convertible into
Common Stock) at a price (the "Subscription Price") (or having a conversion
price per share) less than the current market price per share of Common Stock as
determined pursuant to Section 7(e) on such record date, the Exercise Price
shall be adjusted so that the same shall equal the price determined by
multiplying the same by a fraction, the numerator of which shall be the sum of
the number of shares of Common Stock outstanding on the record date mentioned
below and the number of additional shares of Common Stock which the aggregate
offering price of the total number of shares of Common Stock so offered (or the
aggregate conversion price of the convertible securities so offered) would
purchase at the current market price per share of Common Stock on such record
date, and the denominator of which shall be the sum of the number of shares of
Common Stock outstanding on the record date mentioned below and the number of
additional shares of Common Stock offered for subscription or purchase (or into
which the convertible securities so offered are convertible). Such adjustment
shall be made successively whenever such rights or warrants are issued and shall
become effective immediately after the record date for the determination of
stockholders entitled to receive such rights or warrants; and to the extent that
shares of Common Stock are not delivered (or securities convertible into Common
Stock are not delivered) after the expiration of such rights or warrants the
Exercise Price shall be readjusted to the Exercise Price which would then be in
effect had the adjustments made upon the issuance of such rights or warrants
been made upon the basis of delivery of only the number of shares of Common
Stock (or securities convertible into Common Stock) actually delivered. This
Section 7(b) shall not apply to the occurrence of a "Distribution Date" under
the Rights Agreement.

            (c) In case the Company shall hereafter distribute to all holders of
its Common Stock evidences of its indebtedness or assets (excluding cash
dividends or distributions and dividends or distributions referred to in Section
7(a) above) or subscription rights or warrants (excluding those referred to in
Section 7(b) above), then in each such case the Exercise Price shall be adjusted
by multiplying the same by a fraction, the numerator of which shall be the total
number of shares of Common Stock then outstanding multiplied by the current
market price per share of Common Stock (as defined in Section 7(e) below), less
the fair market value (as determined by the Company's Board of Directors) of
said assets, or evidences of indebtedness so distributed or of such rights or
warrants, and the denominator of which shall be the total number of shares of
Common Stock outstanding multiplied by such current market price per share of
Common Stock. Such adjustment shall be made whenever any such distribution is
made and shall become effective immediately after the record date for the
determination of stockholders entitled to receive such distribution and to the
extent that any subscription rights or warrants are not exercised before the
expiration of such rights or warrants the Exercise Price shall be readjusted to
the Exercise Price which would then be in effect had the adjustments made upon
the issuance of such rights or warrants been made upon the basis of delivery of
only the number of rights or warrants actually exercised. This Section 7(c)
shall not apply to the occurrence of a "Distribution Date" under the Rights
Agreement.

            (d) Whenever the Exercise Price payable upon exercise of this
Warrant is adjusted pursuant to Sections (a), (b) or (c) above, the number of
Shares purchasable upon exercise of this Warrant shall simultaneously be
adjusted by multiplying the number of Shares issuable upon exercise of this
Warrant by the Exercise Price in effect immediately prior to such adjustment and
dividing the product so obtained by the Exercise Price, as adjusted.

            (e) For the purpose of any computation under Subsection (c) above,
the current market price per share of Common Stock at any date shall be deemed
to be the closing price on the Trading Day immediately preceding the date as of
which the current market price is being determined, provided that if the Common
Stock is not then listed on any market or exchange, then the current market
price shall be the average of the closing bid prices for the Common Stock on the
OTC Bulletin Board, or, if such is not available, the Pink Sheets LLC (formerly
the National Quotation Bureau), or otherwise the average of the closing bid
prices for the Common Stock quoted by two market-makers of the Common Stock, or
otherwise such Market Price shall be the fair market value of one share of
Common Stock as reasonably determined in good faith by the Company and the
Holders. "Closing price" shall mean the last sale price for the Common Stock on
the Principal Market on any particular Trading Day.

                                       3
<PAGE>

            (f) No adjustment in the Exercise Price shall be required unless
such adjustment would require an increase or decrease of at least five cents
($0.05) in such price; provided, however, that any adjustments which may by
reason of this Section 7(f) not be required to be made shall be carried forward
and taken into account in any subsequent adjustment required to be made
hereunder. All calculations under this Section 7 shall be made to the nearest
cent or to the nearest one-hundredth of a share, as the case may be. Anything in
this Section 7 to the contrary notwithstanding, the Company shall be entitled,
but shall not be required, to make such changes in the Exercise Price, in
addition to those required by this Section 7, as it shall determine, in its sole
discretion, to be advisable in order that any dividend or distribution in shares
of Common Stock, or any subdivision, reclassification or combination of Common
Stock hereafter made by the Company shall not result in any Federal income tax
liability to the holders of the Common Stock or securities convertible into
Common Stock.

            (g) Whenever the Exercise Price is adjusted, as herein provided, the
Company shall promptly cause a notice setting forth the adjusted Exercise Price
and adjusted number of Shares issuable upon exercise of this Warrant to be
mailed to the Holder, at its address set forth herein, and shall cause a
certified copy thereof to be mailed to the Company's transfer agent, if any. The
Company may retain a firm of independent certified public accountants selected
by the Board of Directors (who may be the regular accountants employed by the
Company) to make any computation required by this Section 7, and a certificate
signed by such firm shall be conclusive evidence of the correctness of such
adjustment.

            (h) In the event that at any time, as a result of an adjustment made
pursuant to the provisions of this Section 7, the Holder of this Warrant
thereafter shall become entitled to receive any shares of the Company other than
Common Stock, thereafter the number of such other shares so receivable upon
exercise of this Warrant shall be subject to adjustment from time to time in a
manner and on terms as nearly equivalent as practicable to the provisions with
respect to the Common Stock contained in Sections 7(a) to (f), inclusive, above.

      8. This Warrant shall be governed by and in accordance with the laws of
the State of Delaware without regard to conflict of laws principles thereof.

      9. In case of any consolidation of the Company with, or merger of the
Company into, any other entity, or in case of any sale or conveyance of all or
substantially all of the assets of the Company other than in connection with a
plan of complete liquidation of the Company at any time prior to the Expiration
Date, then as a condition of such consolidation, merger or sale or conveyance,
the Company shall give written notice of consolidation, merger, sale or
conveyance to the Holder and, from and after the effective date of such
consolidation, merger, sale or conveyance this Warrant shall represent only the
right to receive the consideration that would have been issuable in respect of
the Shares underlying this Warrant in such consolidation, merger, sale or
conveyance had this Warrant been exercised in full immediately prior to such
effective time and the Holder shall have no further rights under this Warrant
other than the right to receive such consideration.

         [The remainder of this page has been intentionally left blank.]

                            [Signature Page Follows]

                                       4
<PAGE>

      IN WITNESS WHEREOF, the Company has caused this Warrant to be signed by
its duly authorized officer under its corporate seal, and this Warrant to be
dated February 19, 2004.

                                         BIOPURE CORPORATION

                                         By: __________________________________
                                             Name: Francis H. Murphy
                                             Title: Chief Financial Officer

                                       5
<PAGE>

                                  PURCHASE FORM

                  (To be signed only upon exercise of Warrant)

      The undersigned, the holder of the foregoing Warrant, hereby irrevocably
elects to exercise the purchase rights represented by such Warrant for, and to
purchase thereunder, _______________ Shares of Class A Common Stock, $0.01 par
value per share (the "Shares"), of BIOPURE CORPORATION and tenders herewith
payment of the aggregate Exercise Price in respect of the Shares in full, in the
amount of $_________; and requests that the certificates for the Shares be
issued in the name(s) of, and delivered to _________________, whose address(es)
is (are):

Dated: _______________, ____

                                                     By: _____________________

                                                     _________________________

                                                     _________________________
                                                     Address

<PAGE>

                                  TRANSFER FORM

                  (To be signed only upon transfer of Warrant)

      For value received, the undersigned hereby sells, assigns, and transfers
unto ____________________ the right to purchase Shares represented by the
foregoing Warrant to the extent of __________ Shares, and appoints
_________________________ attorney to transfer such rights on the books of
Biopure Corporation, with full power of substitution in the premises.

Dated: _______________, ____

                                                     By:______________________

                                                     _________________________

                                                     _________________________
                                                     Address

In the presence of:

_________________________

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