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EXHIBIT 4.4




ARDEA BIOSCIENCES, INC.

and

, AS WARRANT AGENT




FORM OF COMMON STOCK

WARRANT AGREEMENT



 









 





ARDEA BIOSCIENCES, INC.




COMMON STOCK WARRANT AGREEMENT



     COMMON STOCK WARRANT AGREEMENT (this “Agreement”), dated as of                 between ARDEA
BIOSCIENCES, INC., a Delaware corporation (the “Company”) and, a [corporation] [national banking
association] organized and existing under the laws of                and having a corporate trust
office in                , as warrant agent (the “Warrant Agent”).



     WHEREAS, the Company proposes to sell [if Warrants are sold with other securities—[title of
such other securities being offered] (the “Other Securities”) with] warrant certificates evidencing
one or more warrants (the “Warrants” or, individually, a “Warrant”) representing the right to
purchase Common Stock of the Company, par value $0.001 per share (the “Warrant Securities”), such
warrant certificates and other warrant certificates issued pursuant to this Agreement being herein
called the “Warrant Certificates”; and



     WHEREAS, the Company desires the Warrant Agent to act on behalf of the Company, and the
Warrant Agent is willing so to act, in connection with the issuance, registration, transfer,
exchange, exercise and replacement of the Warrant Certificates, and in this Agreement wishes to set
forth, among other things, the form and provisions of the Warrant Certificates and the terms and
conditions on which they may be issued, registered, transferred, exchanged, exercised and replaced.



     NOW THEREFORE, in consideration of the premises and of the mutual agreements herein contained,
the parties hereto agree as follows:



ARTICLE 1




ISSUANCE OF WARRANTS AND EXECUTION AND DELIVERY OF WARRANT CERTIFICATES



     1.1 Issuance Of Warrants. [If Warrants alone—Upon issuance, each Warrant Certificate shall
evidence one or more Warrants.] [If Other Securities and Warrants—Warrant Certificates shall be
[initially] issued in connection with the issuance of the Other Securities [but shall be separately
transferable on and after                (the “Detachable Date”)] [and shall not be separately
transferable] and each Warrant Certificate shall evidence one or more Warrants.] Each Warrant
evidenced thereby shall represent the right, subject to the provisions contained herein and
therein, to purchase one Warrant Security. [If Other Securities and Warrants—Warrant Certificates
shall be initially issued in units with the Other Securities and each Warrant Certificate included
in such a unit shall evidence                Warrants for each [ $                principal amount] [
               shares] of Other Securities included in such unit.]



     1.2 Execution And Delivery Of Warrant Certificates. Each Warrant Certificate, whenever issued,
shall be in registered form substantially in the form set forth in Exhibit A hereto, shall be dated
the date of its countersignature by the Warrant Agent and may have such letters, numbers, or other
marks of identification or designation and such legends or endorsements printed, lithographed or
engraved thereon as the officers of the Company executing the same may approve (execution thereof
to be conclusive evidence of such approval) and as are not inconsistent with the provisions of this
Agreement, or as may be required to comply with any law or with any rule or regulation made
pursuant thereto or with any rule or regulation of any securities exchange on which the Warrants
may be listed, or to conform to usage. The Warrant Certificates shall be signed on behalf of the
Company by any of its present or future chief executive officers, presidents, senior vice
presidents, vice presidents, chief financial officers, chief legal officers, treasurers, assistant
treasurers, controllers, assistant controllers, secretaries or assistant secretaries under its
corporate seal reproduced thereon. Such signatures may be manual or facsimile signatures of such
authorized officers and may be imprinted or otherwise reproduced on the Warrant Certificates. The
seal of the Company may be in the form of a facsimile thereof and may be impressed, affixed,
imprinted or otherwise reproduced on the Warrant Certificates.



     No Warrant Certificate shall be valid for any purpose, and no Warrant evidenced
thereby shall be exercisable, until such Warrant Certificate has been countersigned by the manual
signature of the Warrant Agent. Such signature



 









 







by the Warrant Agent upon any Warrant Certificate executed by the Company shall be conclusive evidence that the Warrant Certificate so countersigned
has been duly issued hereunder.



     In case any officer of the Company who shall have signed any of the Warrant Certificates
either manually or by facsimile signature shall cease to be such officer before the Warrant
Certificates so signed shall have been countersigned and delivered by the Warrant Agent, such
Warrant Certificates may be countersigned and delivered notwithstanding that the person who signed
Warrant Certificates ceased to be such officer of the Company; and any Warrant Certificate may be
signed on behalf of the Company by such persons as, at the actual date of the execution of such
Warrant Certificate, shall be the proper officers of the Company, although at the date of the
execution of this Agreement any such person was not such officer.



     The term “holder” or “holder of a Warrant Certificate” as used herein shall mean any person in
whose name at the time any Warrant Certificate shall be registered upon the books to be maintained
by the Warrant Agent for that purpose [If Other Securities and Warrants are not immediately
detachable—or upon the registration of the Other Securities prior to the Detachable Date. Prior to
the Detachable Date, the Company will, or will cause the registrar of the Other Securities to, make
available at all times to the Warrant Agent such information as to holders of the Other Securities
as may be necessary to keep the Warrant Agent’s records up to date].



     1.3 Issuance Of Warrant Certificates. Warrant Certificates evidencing the right to purchase
Warrant Securities may be executed by the Company and delivered to the Warrant Agent upon the
execution of this Warrant Agreement or from time to time thereafter. The Warrant Agent shall, upon
receipt of Warrant Certificates duly executed on behalf of the Company, countersign such Warrant
Certificates and shall deliver such Warrant Certificates to or upon the order of the Company.



ARTICLE 2




WARRANT PRICE, DURATION AND EXERCISE OF WARRANTS



     2.1 Warrant Price. During the period specified in Section 2.2, each Warrant shall, subject to
the terms of this Warrant Agreement and the applicable Warrant Certificate, entitle the holder
thereof to purchase the number of Warrant Securities specified in the applicable Warrant
Certificate at an exercise price of $  per Warrant Security, subject to adjustment upon the
occurrence of certain events, as hereinafter provided. Such purchase price per Warrant Security is
referred to in this Agreement as the “Warrant Price.”



     2.2 Duration Of Warrants. Each Warrant may be exercised in whole or in part at any time, as
specified herein, on or after [the date thereof] [               ] and at or before [               ]
p.m., [City] time, on                or such later date as the Company may designate by notice to
the Warrant Agent and the holders of Warrant Certificates mailed to their addresses as set forth in
the record books of the Warrant Agent (the “Expiration Date”). Each Warrant not exercised at or
before [               ] p.m., [City] time, on the Expiration Date shall become void, and all rights of
the holder of the Warrant Certificate evidencing such Warrant under this Agreement shall cease.



     2.3 Exercise Of Warrants.



          (a) During the period specified in Section 2.2, the Warrants may be exercised to purchase a
whole number of Warrant Securities in registered form by providing certain information as set forth
on the reverse side of the Warrant Certificate and by paying in full, in lawful money of the United
States of America, [in cash or by certified check or official bank check in New York Clearing House
funds] [by bank wire transfer in immediately available funds] the Warrant Price for each Warrant
Security with respect to which a Warrant is being exercised to the Warrant Agent at its corporate
trust office, provided that such exercise is subject to receipt within five business days of such
payment by the Warrant Agent of the Warrant Certificate with the form of election to purchase
Warrant Securities set forth on the reverse side of the Warrant Certificate properly completed and
duly executed. The date on which payment in full of the Warrant Price is received by the Warrant
Agent shall, subject to receipt of the Warrant Certificate as aforesaid, be deemed to be the date
on which the Warrant is exercised; provided, however, that if, at the date of receipt of such



 









 







Warrant Certificates and payment in full of the Warrant Price, the transfer books for the
Warrant Securities purchasable upon the exercise of such Warrants shall be closed, no such receipt
of such Warrant Certificates and no such payment of such Warrant Price shall be effective to
constitute the person so designated to be named as the holder of record of such Warrant Securities on such date, but shall be effective to constitute such
person as the holder of record of such Warrant Securities for all purposes at the opening of
business on the next succeeding day on which the transfer books for the Warrant Securities
purchasable upon the exercise of such Warrants shall be opened, and the certificates for the
Warrant Securities in respect of which such Warrants are then exercised shall be issuable as of the
date on such next succeeding day on which the transfer books shall next be opened, and until such
date the Company shall be under no duty to deliver any certificate for such Warrant Securities. The
Warrant Agent shall deposit all funds received by it in payment of the Warrant Price in an account
of the Company maintained with it and shall advise the Company by telephone at the end of each day
on which a payment for the exercise of Warrants is received of the amount so deposited to its
account. The Warrant Agent shall promptly confirm such telephone advice to the Company in writing.



          (b) The Warrant Agent shall, from time to time, as promptly as practicable, advise the Company
of (i) the number of Warrant Securities with respect to which Warrants were exercised, (ii) the
instructions of each holder of the Warrant Certificates evidencing such Warrants with respect to
delivery of the Warrant Securities to which such holder is entitled upon such exercise, (iii)
delivery of Warrant Certificates evidencing the balance, if any, of the Warrants for the remaining
Warrant Securities after such exercise, and (iv) such other information as the Company shall
reasonably require.



          (c) As soon as practicable after the exercise of any Warrant, the Company shall issue to or
upon the order of the holder of the Warrant Certificate evidencing such Warrant the Warrant
Securities to which such holder is entitled, in fully registered form, registered in such name or
names as may be directed by such holder. If fewer than all of the Warrants evidenced by such
Warrant Certificate are exercised, the Company shall execute, and an authorized officer of the
Warrant Agent shall manually countersign and deliver, a new Warrant Certificate evidencing Warrants
for the number of Warrant Securities remaining unexercised.



          (d) The Company shall not be required to pay any stamp or other tax or other governmental
charge required to be paid in connection with any transfer involved in the issue of the Warrant
Securities, and in the event that any such transfer is involved, the Company shall not be required
to issue or deliver any Warrant Security until such tax or other charge shall have been paid or it
has been established to the Company’s satisfaction that no such tax or other charge is due.



          (e) Prior to the issuance of any Warrants there shall have been reserved, and the Company
shall at all times through the Expiration Date keep reserved, out of its authorized but unissued
Warrant Securities, a number of shares sufficient to provide for the exercise of the Warrants.



ARTICLE 3




OTHER PROVISIONS RELATING TO RIGHTS OF HOLDERS OF WARRANT CERTIFICATES



     3.1 No Rights As Warrant Securityholder Conferred By Warrants Or Warrant Certificates. No
Warrant Certificate or Warrant evidenced thereby shall entitle the holder thereof to any of the
rights of a holder of Warrant Securities, including, without limitation, the right to receive the
payment of dividends or distributions, if any, on the Warrant Securities or to exercise any voting
rights, except to the extent expressly set forth in this Agreement or the applicable Warrant
Certificate.



     3.2 Lost, Stolen, Mutilated Or Destroyed Warrant Certificates. Upon receipt by the Warrant
Agent of evidence reasonably satisfactory to it and the Company of the ownership of and the loss,
theft, destruction or mutilation of any Warrant Certificate and/or indemnity reasonably
satisfactory to the Warrant Agent and the Company and, in the case of mutilation, upon surrender of
the mutilated Warrant Certificate to the Warrant Agent for cancellation, then, in the absence of
notice to the Company or the Warrant Agent that such Warrant Certificate has been acquired by a
bona fide purchaser, the Company shall execute, and an authorized officer of the Warrant Agent
shall manually countersign and deliver, in exchange for or in lieu of the lost, stolen, destroyed
or mutilated Warrant Certificate, a new Warrant Certificate of the same tenor and evidencing
Warrants for a like number of



 









 







Warrant Securities. Upon the issuance of any new Warrant Certificate
under this Section 3.2, the Company may require the payment of a sum sufficient to cover any tax or
other governmental charge that may be imposed in relation thereto and any other expenses (including
the fees and expenses of the Warrant Agent) in connection therewith. Every substitute Warrant Certificate executed and delivered pursuant to this Section 3.2
in lieu of any lost, stolen or destroyed Warrant Certificate shall represent an additional
contractual obligation of the Company, whether or not the lost, stolen or destroyed Warrant
Certificate shall be at any time enforceable by anyone, and shall be entitled to the benefits of
this Agreement equally and proportionately with any and all other Warrant Certificates duly
executed and delivered hereunder. The provisions of this Section 3.2 are exclusive and shall
preclude (to the extent lawful) all other rights and remedies with respect to the replacement of
mutilated, lost, stolen or destroyed Warrant Certificates.



     3.3 Holder Of Warrant Certificate May Enforce Rights. Notwithstanding any of the provisions of
this Agreement, any holder of a Warrant Certificate, without the consent of the Warrant Agent, the
holder of any Warrant Securities or the holder of any other Warrant Certificate, may, in such
holder’s own behalf and for such holder’s own benefit, enforce, and may institute and maintain any
suit, action or proceeding against the Company suitable to enforce, or otherwise in respect of,
such holder’s right to exercise the Warrants evidenced by such holder’s Warrant Certificate in the
manner provided in such holder’s Warrant Certificate and in this Agreement.



     3.4 Adjustments.



          (a) In case the Company shall at any time subdivide its outstanding shares of Common Stock
into a greater number of shares, the Warrant Price in effect immediately prior to such subdivision
shall be proportionately reduced and the number of Warrant Securities purchasable under the
Warrants shall be proportionately increased. Conversely, in case the outstanding shares of Common
Stock of the Company shall be combined into a smaller number of shares, the Warrant Price in effect
immediately prior to such combination shall be proportionately increased and the number of Warrant
Securities purchasable under the Warrants shall be proportionately decreased.



          (b) If at any time or from time to time the holders of Common Stock (or any shares of stock or
other securities at the time receivable upon the exercise of the Warrants) shall have received or
become entitled to receive, without payment therefore,



               (i) Common Stock or any shares of stock or other securities which are at any time directly or
indirectly convertible into or exchangeable for Common Stock, or any rights or options to subscribe
for, purchase or otherwise acquire any of the foregoing by way of dividend or other distribution;



               (ii) any cash paid or payable otherwise than as a cash dividend paid or payable out of the
Company’s current or retained earnings;



               (iii) any evidence of the Company’s indebtedness or rights to subscribe for or purchase the
Company’s indebtedness; or



               (iv) Common Stock or additional stock or other securities or property (including cash) by way
of spinoff, split-up, reclassification, combination of shares or similar corporate rearrangement
(other than shares of Common Stock issued as a stock split or adjustments in respect of which shall
be covered by the terms of Section 3.4(a) above), then and in each such case, the holder of each
Warrant shall, upon the exercise of the Warrant, be entitled to receive, in addition to the number
of Warrant Securities receivable thereupon, and without payment of any additional consideration
therefore, the amount of stock and other securities and property (including cash and indebtedness
or rights to subscribe for or purchase indebtedness) which such holder would hold on the date of
such exercise had he been the holder of record of such Warrant Securities as of the date on which
holders of Common Stock received or became entitled to receive such shares or all other additional
stock and other securities and property.



          (c) In case of (i) any reclassification, capital reorganization, or change in the Common Stock
of the Company (other than as a result of a subdivision, combination, or stock dividend provided
for in Section 3.4(a) or Section 3.4(b) above), (ii) share exchange, merger or similar transaction
of the Company with or into another person or entity (other than a share exchange, merger or
similar transaction in which the Company is the acquiring or



 









 







surviving corporation and which does not result in any change in the Common Stock other than the issuance of additional shares of Common
Stock) or (iii) the sale, exchange, lease, transfer or other disposition of all or substantially
all of the properties and assets of the Company as an entirety (in any such case, a “Reorganization
Event”), then, as a condition of such Reorganization Event, lawful provisions shall be made, and
duly executed documents evidencing the same from the Company or its successor shall be delivered to
the holders of the Warrants, so that the holders of the Warrants shall have the right at any time
prior to the expiration of the Warrants to purchase, at a total price equal to that payable upon
the exercise of the Warrants, the kind and amount of shares of stock and other securities and
property receivable in connection with such Reorganization Event by a holder of the same number of
Warrant Securities as were purchasable by the holders of the Warrants immediately prior to such
Reorganization Event. In any such case appropriate provisions shall be made with respect to the
rights and interests of the holders of the Warrants so that the provisions hereof shall thereafter
be applicable with respect to any shares of stock or other securities and property deliverable upon
exercise the Warrants, and appropriate adjustments shall be made to the Warrant Price payable
hereunder provided the aggregate purchase price shall remain the same. In the case of any
transaction described in clauses (ii) and (iii) above, the Company shall thereupon be relieved of
any further obligation hereunder or under the Warrants, and the Company as the predecessor
corporation may thereupon or at any time thereafter be dissolved, wound up or liquidated. Such
successor or assuming entity thereupon may cause to be signed, and may issue either in its own name
or in the name of the Company, any or all of the Warrants issuable hereunder which heretofore shall
not have been signed by the Company, and may execute and deliver securities in its own name, in
fulfillment of its obligations to deliver Warrant Securities upon exercise of the Warrants. All the
Warrants so issued shall in all respects have the same legal rank and benefit under this Agreement
as the Warrants theretofore or thereafter issued in accordance with the terms of this Agreement as
though all of such Warrants had been issued at the date of the execution hereof. In any case of any
such Reorganization Event, such changes in phraseology and form (but not in substance) may be made
in the Warrants thereafter to be issued as may be appropriate.



     The Warrant Agent may receive a written opinion of legal counsel as conclusive evidence that
any such Reorganization Event complies with the provisions of this Section 3.4.



          (d) The Company may, at its option, at any time until the Expiration Date, reduce the then
current Warrant Price to any amount deemed appropriate by the Board of Directors of the Company for
any period not exceeding twenty consecutive days (as evidenced in a resolution adopted by such
Board of Directors), but only upon giving the notices required by Section 3.5 at least ten days
prior to taking such action.



          (e) Except as herein otherwise expressly provided, no adjustment in the Warrant Price shall be
made by reason of the issuance of shares of Common Stock, or securities convertible into or
exchangeable for shares of Common Stock, or securities carrying the right to purchase any of the
foregoing or for any other reason whatsoever.



          (f) No fractional Warrant Securities shall be issued upon the exercise of Warrants. If more
than one Warrant shall be exercised at one time by the same holder, the number of full Warrant
Securities which shall be issuable upon such exercise shall be computed on the basis of the
aggregate number of Warrant Securities purchased pursuant to the Warrants so exercised. Instead of
any fractional Warrant Security which would otherwise be issuable upon exercise of any Warrant, the
Company shall pay a cash adjustment in respect of such fraction in an amount equal to the same
fraction of the last reported sale price (or bid price if there were no sales) per Warrant
Security, in either case as reported on the principal registered national securities exchange on
which the Warrant Securities are listed or admitted to trading on the business day that next
precedes the day of exercise or, if the Warrant Securities are not then listed or admitted to
trading on any registered national securities exchange, the average of the closing high bid and low
asked prices as reported on the OTC Bulletin Board Service (the “OTC Bulletin Board”) operated by
the Financial Industry Regulatory Authority, Inc. (“FINRA”) or, if not available on the OTC
Bulletin Board, then the average of the closing high bid and low asked prices as reported on any
other U.S. quotation medium or inter-dealer quotation system on such date, or if on any such date
the Warrant Securities are not listed or admitted to trading on a registered national securities
exchange, are not included in the OTC Bulletin Board, and are not quoted on any other U.S.
quotation medium or inter-dealer quotation system, an amount equal to the same fraction of the
average of the closing bid and asked prices as furnished by any FINRA member firm selected from
time to time by the Company for that purpose at the close of business on the business day that next
precedes the day of exercise.



 









 





          (g) Whenever the Warrant Price then in effect is adjusted as herein
provided, the Company shall mail to each holder of the Warrants at such holder’s address as it
shall appear on the books of the Company a statement setting forth the adjusted Warrant Price then
and thereafter effective under the provisions hereof, together with the facts, in reasonable
detail, upon which such adjustment is based.



     3.5 Notice To Warrantholders. In case the Company shall (a) effect any dividend or
distribution described in Section 3.4(b), (b) effect any Reorganization Event, (c) make any
distribution on or in respect of the Common Stock in connection with the dissolution, liquidation
or winding up of the Company, or (d) reduce the then current Warrant Price pursuant to Section
3.4(d), then the Company shall mail to each holder of Warrants at such holder’s address as it shall
appear on the books of the Warrant Agent, at least ten days prior to the applicable date
hereinafter specified, a notice stating (x) the record date for such dividend or distribution, or,
if a record is not to be taken, the date as of which the holders of record of Common Stock that
will be entitled to such dividend or distribution are to be determined, (y) the date on which such
Reorganization Event, dissolution, liquidation or winding up is expected to become effective, and
the date as of which it is expected that holders of Common Stock of record shall be entitled to
exchange their shares of Common Stock for securities or other property deliverable upon such
Reorganization Event, dissolution, liquidation or winding up, or (z) the first date on which the
then current Warrant Price shall be reduced pursuant to Section 3.4(d). No failure to mail such
notice nor any defect therein or in the mailing thereof shall affect any such transaction or any
adjustment in the Warrant Price required by Section 3.4.



     3.6 [If The Warrants Are Subject To Acceleration By The Company, Insert—Acceleration Of
Warrants By The Company.



          (a) At any time on or after      , the Company shall have the right to
accelerate any or all Warrants at any time by causing them to expire at the close of business on
the day next preceding a specified date (the “Acceleration Date”), if the Market Price (as
hereinafter defined) of the Common Stock equals or exceeds            percent
(            %) of the then effective Warrant Price on any twenty Trading Days (as hereinafter defined)
within a period of thirty consecutive Trading Days ending no more than five Trading Days prior to
the date on which the Company gives notice to the Warrant Agent of its election to accelerate the
Warrants.



          (b) “Market Price” for each Trading Day shall be, if the Common Stock is listed or admitted to
trading on any registered national securities exchange, the last reported sale price, regular way
(or, if no such price is reported, the average of the reported closing bid and asked prices,
regular way) of Common Stock, in either case as reported on the principal registered national
securities exchange on which the Common Stock is listed or admitted to trading or, if not listed or
admitted to trading on any registered national securities exchange, the average of the closing high
bid and low asked prices as reported on the OTC Bulletin Board operated by FINRA, or if not
available on the OTC Bulletin Board, then the average of the closing high bid and low asked prices
as reported on any other U.S. quotation medium or inter-dealer quotation system, or if on any such
date the shares of Common Stock are not listed or admitted to trading on a registered national
securities exchange, are not included in the OTC Bulletin Board, and are not quoted on any other
U.S. quotation medium or inter-dealer quotation system, the average of the closing bid and asked
prices as furnished by any FINRA member firm selected from time to time by the Company for that
purpose. “Trading Day” shall be each Monday through Friday, other than any day on which securities
are not traded in the system or on the exchange that is the principal market for the Common Stock,
as determined by the Board of Directors of the Company.



          (c) In the event of an acceleration of less than all of the Warrants, the Warrant Agent shall
select the Warrants to be accelerated by lot, pro rata or in such other manner as it deems, in its
discretion, to be fair and appropriate.



          (d) Notice of an acceleration specifying the Acceleration Date shall be sent by mail first
class, postage prepaid, to each registered holder of a Warrant Certificate representing a Warrant
accelerated at such holder’s address appearing on the books of the Warrant Agent not more than
sixty days nor less than thirty days before the Acceleration Date. Such notice of an acceleration
also shall be given no more than twenty days, and no less than ten days, prior to the mailing of
notice to registered holders of Warrants pursuant to this Section 3.6, by publication at least once
in a newspaper of general circulation in the City of New York.



          (e) Any Warrant accelerated may be exercised until [             ] p.m., [City] time, on the
business day next preceding the Acceleration Date. The Warrant Price shall be payable as provided
in Section 2.]



 









 





ARTICLE 4




EXCHANGE AND TRANSFER OF WARRANT CERTIFICATES



     4.1 Exchange And Transfer Of Warrant Certificates. [If Other Securities with Warrants which
are immediately detachable—Upon] [If Other Securities with Warrants which are not immediately
detachable—Prior to the Detachable Date, a Warrant Certificate may be exchanged or transferred
only together with the Other Security to which the Warrant Certificate was initially attached, and
only for the purpose of effecting or in conjunction with an exchange or transfer of such Other
Security. Prior to any Detachable Date, each transfer of the Other Security shall operate also to
transfer the related Warrant Certificates. After the Detachable Date, upon] surrender at the
corporate trust office of the Warrant Agent, Warrant Certificates evidencing Warrants may be
exchanged for Warrant Certificates in other denominations evidencing such Warrants or the transfer
thereof may be registered in whole or in part; provided that such other Warrant Certificates
evidence Warrants for the same aggregate number of Warrant Securities as the Warrant Certificates
so surrendered. The Warrant Agent shall keep, at its corporate trust office, books in which,
subject to such reasonable regulations as it may prescribe, it shall register Warrant Certificates
and exchanges and transfers of outstanding Warrant Certificates, upon surrender of the Warrant
Certificates to the Warrant Agent at its corporate trust office for exchange or registration of
transfer, properly endorsed or accompanied by appropriate instruments of registration of transfer
and written instructions for transfer, all in form satisfactory to the Company and the Warrant
Agent. No service charge shall be made for any exchange or registration of transfer of Warrant
Certificates, but the Company may require payment of a sum sufficient to cover any stamp or other
tax or other governmental charge that may be imposed in connection with any such exchange or
registration of transfer. Whenever any Warrant Certificates are so surrendered for exchange or
registration of transfer, an authorized officer of the Warrant Agent shall manually countersign and
deliver to the person or persons entitled thereto a Warrant Certificate or Warrant Certificates
duly authorized and executed by the Company, as so requested. The Warrant Agent shall not be
required to effect any exchange or registration of transfer which will result in the issuance of a
Warrant Certificate evidencing a Warrant for a fraction of a Warrant Security or a number of
Warrants for a whole number of Warrant Securities and a fraction of a Warrant Security. All Warrant
Certificates issued upon any exchange or registration of transfer of Warrant Certificates shall be
the valid obligations of the Company, evidencing the same obligations and entitled to the same
benefits under this Agreement as the Warrant Certificate surrendered for such exchange or
registration of transfer.



     4.2 Treatment Of Holders Of Warrant Certificates. [If Other Securities and Warrants are not
immediately detachable—Prior to the Detachable Date, the Company, the Warrant Agent and all other
persons may treat the owner of the Other Security as the owner of the Warrant Certificates
initially attached thereto for any purpose and as the person entitled to exercise the rights
represented by the Warrants evidenced by such Warrant Certificates, any notice to the contrary
notwithstanding. After the Detachable Date and prior to due presentment of a Warrant Certificate
for registration of transfer, the] [The] Company, the Warrant Agent and all other persons may treat
the registered holder of a Warrant Certificate as the absolute owner thereof for any purpose and as
the person entitled to exercise the rights represented by the Warrants evidenced thereby, any
notice to the contrary notwithstanding.



     4.3 Cancellation Of Warrant Certificates. Any Warrant Certificate surrendered for exchange,
registration of transfer or exercise of the Warrants evidenced thereby shall, if surrendered to the
Company, be delivered to the Warrant Agent and all Warrant Certificates surrendered or so delivered
to the Warrant Agent shall be promptly canceled by the Warrant Agent and shall not be reissued and,
except as expressly permitted by this Agreement, no Warrant Certificate shall be issued hereunder
in exchange therefor or in lieu thereof.



     The Warrant Agent shall deliver to the Company from time to time or otherwise dispose of
canceled Warrant Certificates in a manner satisfactory to the Company.



ARTICLE 5




CONCERNING THE WARRANT AGENT



     5.1 Warrant Agent. The Company hereby appoints                as Warrant Agent of the
Company in respect of the Warrants and the Warrant Certificates upon the terms and subject to the
conditions herein set forth, and



 









 







               hereby accepts such appointment. The Warrant Agent shall have the powers and authority granted to and conferred upon it in the Warrant
Certificates and hereby and such further powers and authority to act on behalf of the Company as
the Company may hereafter grant to or confer upon it. All of the terms and provisions with respect
to such powers and authority contained in the Warrant Certificates are subject to and governed by the
terms and provisions hereof.



     5.2 Conditions Of Warrant Agent’s Obligations. The Warrant Agent accepts its obligations
herein set forth upon the terms and conditions hereof, including the following to all of which the
Company agrees and to all of which the rights hereunder of the holders from time to time of the
Warrant Certificates shall be subject:



          (a) Compensation And Indemnification. The Company agrees promptly to pay the Warrant Agent the
compensation to be agreed upon with the Company for all services rendered by the Warrant Agent and
to reimburse the Warrant Agent for reasonable out-of-pocket expenses (including reasonable counsel
fees) incurred without negligence, bad faith or willful misconduct by the Warrant Agent in
connection with the services rendered hereunder by the Warrant Agent. The Company also agrees to
indemnify the Warrant Agent for, and to hold it harmless against, any loss, liability or expense
incurred without negligence, bad faith or willful misconduct on the part of the Warrant Agent,
arising out of or in connection with its acting as Warrant Agent hereunder, including the
reasonable costs and expenses of defending against any claim of such liability.



          (b) Agent For The Company. In acting under this Warrant Agreement and in connection with the
Warrant Certificates, the Warrant Agent is acting solely as agent of the Company and does not
assume any obligations or relationship of agency or trust for or with any of the holders of Warrant
Certificates or beneficial owners of Warrants.



          (c) Counsel. The Warrant Agent may consult with counsel satisfactory to it, which may include
counsel for the Company, and the written advice of such counsel shall be full and complete
authorization and protection in respect of any action taken, suffered or omitted by it hereunder in
good faith and in accordance with the advice of such counsel.



          (d) Documents. The Warrant Agent shall be protected and shall incur no liability for or in
respect of any action taken or omitted by it in reliance upon any Warrant Certificate, notice,
direction, consent, certificate, affidavit, statement or other paper or document reasonably
believed by it to be genuine and to have been presented or signed by the proper parties.



          (e) Certain Transactions. The Warrant Agent, and its officers, directors and employees, may
become the owner of, or acquire any interest in, Warrants, with the same rights that it or they
would have if it were not the Warrant Agent hereunder, and, to the extent permitted by applicable
law, it or they may engage or be interested in any financial or other transaction with the Company
and may act on, or as depositary, trustee or agent for, any committee or body of holders of Warrant
Securities or other obligations of the Company as freely as if it were not the Warrant Agent
hereunder. Nothing in this Warrant Agreement shall be deemed to prevent the Warrant Agent from
acting as trustee under any indenture to which the Company is a party.



          (f) No Liability For Interest. Unless otherwise agreed with the Company, the Warrant Agent
shall have no liability for interest on any monies at any time received by it pursuant to any of
the provisions of this Agreement or of the Warrant Certificates.



          (g) No Liability For Invalidity. The Warrant Agent shall have no liability with respect to any
invalidity of this Agreement or any of the Warrant Certificates (except as to the Warrant Agent’s
countersignature thereon).



          (h) No Responsibility For Representations. The Warrant Agent shall not be responsible for any
of the recitals or representations herein or in the Warrant Certificates (except as to the Warrant
Agent’s countersignature thereon), all of which are made solely by the Company.



          (i) No Implied Obligations. The Warrant Agent shall be obligated to perform only such duties
as are herein and in the Warrant Certificates specifically set forth and no implied duties or
obligations shall be read into this Agreement or the Warrant Certificates against the Warrant
Agent. The Warrant Agent shall not be under any



 









 







obligation to take any action hereunder which may tend to involve it in any expense or liability, the payment of which within a reasonable time is
not, in its reasonable opinion, assured to it. The Warrant Agent shall not be accountable or under
any duty or responsibility for the use by the Company of any of the Warrant Certificates authenticated by the Warrant Agent and delivered by it to the Company pursuant to this Agreement or
for the application by the Company of the proceeds of the Warrant Certificates. The Warrant Agent
shall have no duty or responsibility in case of any default by the Company in the performance of
its covenants or agreements contained herein or in the Warrant Certificates or in the case of the
receipt of any written demand from a holder of a Warrant Certificate with respect to such default,
including, without limiting the generality of the foregoing, any duty or responsibility to initiate
or attempt to initiate any proceedings at law or otherwise or, except as provided in Section 6.2
hereof, to make any demand upon the Company.



     5.3 Resignation, Removal And Appointment Of Successors.



          (a) The Company agrees, for the benefit of the holders from time to time of the Warrant
Certificates, that there shall at all times be a Warrant Agent hereunder until all the Warrants
have been exercised or are no longer exercisable.



          (b) The Warrant Agent may at any time resign as agent by giving written notice to the Company
of such intention on its part, specifying the date on which its desired resignation shall become
effective; provided that such date shall not be less than three months after the date on which such
notice is given unless the Company otherwise agrees. The Warrant Agent hereunder may be removed at
any time by the filing with it of an instrument in writing signed by or on behalf of the Company
and specifying such removal and the intended date when it shall become effective. Such resignation
or removal shall take effect upon the appointment by the Company, as hereinafter provided, of a
successor Warrant Agent (which shall be a bank or trust company authorized under the laws of the
jurisdiction of its organization to exercise corporate trust powers) and the acceptance of such
appointment by such successor Warrant Agent. The obligation of the Company under Section 5.2(a)
shall continue to the extent set forth therein notwithstanding the resignation or removal of the
Warrant Agent.



          (c) In case at any time the Warrant Agent shall resign, or shall be removed, or shall become
incapable of acting, or shall be adjudged a bankrupt or insolvent, or shall commence a voluntary
case under the Federal bankruptcy laws, as now or hereafter constituted, or under any other
applicable Federal or state bankruptcy, insolvency or similar law or shall consent to the
appointment of or taking possession by a receiver, custodian, liquidator, assignee, trustee,
sequestrator (or other similar official) of the Warrant Agent or its property or affairs, or shall
make an assignment for the benefit of creditors, or shall admit in writing its inability to pay its
debts generally as they become due, or shall take corporate action in furtherance of any such
action, or a decree or order for relief by a court having jurisdiction in the premises shall have
been entered in respect of the Warrant Agent in an involuntary case under the Federal bankruptcy
laws, as now or hereafter constituted, or any other applicable Federal or state bankruptcy,
insolvency or similar law, or a decree or order by a court having jurisdiction in the premises
shall have been entered for the appointment of a receiver, custodian, liquidator, assignee,
trustee, sequestrator (or similar official) of the Warrant Agent or of its property or affairs, or
any public officer shall take charge or control of the Warrant Agent or of its property or affairs
for the purpose of rehabilitation, conservation, winding up or liquidation, a successor Warrant
Agent, qualified as aforesaid, shall be appointed by the Company by an instrument in writing, filed
with the successor Warrant Agent. Upon the appointment as aforesaid of a successor Warrant Agent
and acceptance by the successor Warrant Agent of such appointment, the Warrant Agent shall cease to
be Warrant Agent hereunder.



          (d) Any successor Warrant Agent appointed hereunder shall execute, acknowledge and deliver to
its predecessor and to the Company an instrument accepting such appointment hereunder, and
thereupon such successor Warrant Agent, without any further act, deed or conveyance, shall become
vested with all the authority, rights, powers, trusts, immunities, duties and obligations of such
predecessor with like effect as if originally named as Warrant Agent hereunder, and such
predecessor, upon payment of its charges and disbursements then unpaid, shall thereupon become
obligated to transfer, deliver and pay over, and such successor Warrant Agent shall be entitled to
receive, all monies, securities and other property on deposit with or held by such predecessor, as
Warrant Agent hereunder.



 









 





          (e) Any corporation into which the Warrant Agent hereunder may be merged or
converted or any corporation with which the Warrant Agent may be consolidated, or any corporation
resulting from any merger, conversion or consolidation to which the Warrant Agent shall be a party,
or any corporation to which the Warrant Agent shall sell or otherwise transfer all or substantially
all the assets and business of the Warrant Agent, provided that it shall be qualified as aforesaid, shall be the successor Warrant Agent under this Agreement without the
execution or filing of any paper or any further act on the part of any of the parties hereto.



ARTICLE 6




MISCELLANEOUS



     6.1 Amendment. This Agreement may be amended by the parties hereto, without the consent of the
holder of any Warrant Certificate, for the purpose of curing any ambiguity, or of curing,
correcting or supplementing any defective provision contained herein, or making any other
provisions with respect to matters or questions arising under this Agreement as the Company and the
Warrant Agent may deem necessary or desirable; provided that such action shall not materially
adversely affect the interests of the holders of the Warrant Certificates.



     6.2 Notices And Demands To The Company And Warrant Agent. If the Warrant Agent shall receive
any notice or demand addressed to the Company by the holder of a Warrant Certificate pursuant to
the provisions of the Warrant Certificates, the Warrant Agent shall promptly forward such notice or
demand to the Company.



     6.3 Addresses. Any communication from the Company to the Warrant Agent with respect to this
Agreement shall be addressed to                , Attention:                and any communication
from the Warrant Agent to the Company with respect to this Agreement shall be addressed to Ardea
Biosciences, Inc., 4939 Directors Place, San Diego, California, 92121, Attention: Corporate
Secretary (or such other address as shall be specified in writing by the Warrant Agent or by the
Company).



     6.4 Governing Law. This Agreement and each Warrant Certificate issued hereunder shall be
governed by and construed in accordance with the laws of the State of New York.



     6.5 Delivery Of Prospectus. The Company shall furnish to the Warrant Agent sufficient copies
of a prospectus meeting the requirements of the Securities Act of 1933, as amended, relating to the
Warrant Securities deliverable upon exercise of the Warrants (the “Prospectus”), and the Warrant
Agent agrees that upon the exercise of any Warrant, the Warrant Agent will deliver to the holder of
the Warrant Certificate evidencing such Warrant, prior to or concurrently with the delivery of the
Warrant Securities issued upon such exercise, a Prospectus.



     The Warrant Agent shall not, by reason of any such delivery, assume any responsibility for the
accuracy or adequacy of such Prospectus.



     6.6 Obtaining Of Governmental Approvals. The Company will from time to time take all action
which may be necessary to obtain and keep effective any and all permits, consents and approvals of
governmental agencies and authorities and securities act filings under United States Federal and
state laws (including without limitation a registration statement in respect of the Warrants and
Warrant Securities under the Securities Act of 1933, as amended), which may be or become requisite
in connection with the issuance, sale, transfer, and delivery of the Warrant Securities issued upon
exercise of the Warrants, the issuance, sale, transfer and delivery of the Warrants or upon the
expiration of the period during which the Warrants are exercisable.



     6.7 Persons Having Rights Under Warrant Agreement. Nothing in this Agreement shall give to any
person other than the Company, the Warrant Agent and the holders of the Warrant Certificates any
right, remedy or claim under or by reason of this Agreement.



     6.8 Headings. The descriptive headings of the several Articles and Sections of this Agreement
are inserted for convenience only and shall not control or affect the meaning or construction of
any of the provisions hereof.



 









 





     6.9 Counterparts. This Agreement may be executed in any number of counterparts, each
of which as so executed shall be deemed to be an original, but such counterparts shall together
constitute but one and the same instrument.



     6.10 Inspection Of Agreement. A copy of this Agreement shall be available at all reasonable
times at the principal corporate trust office of the Warrant Agent for inspection by the holder of
any Warrant Certificate. The Warrant Agent may require such holder to submit his Warrant
Certificate for inspection by it.



     IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be duly executed, all as
of the day and year first above written.




	 	 	 	 	 
	 	ARDEA BIOSCIENCES, INC.

 	 
	 	By  	 	 
	 	 	Its 	 	 
	 



Attest:




	 	 	 	 	 
	 	Warrant Agent 

 	 
	 	By  	 	 
	 	 	Its 	 	 
	 



Attest:




[SIGNATURE PAGE TO COMMON STOCK WARRANT AGREEMENT]









 









 








EXHIBIT A




FORM OF WARRANT CERTIFICATE



[FACE OF WARRANT CERTIFICATE]



	 	 	 

	[[Form if Warrants are attached
to Other Securities and are not immediately detachable.]

	 	[Prior to                , this Warrant
Certificate cannot be transferred or exchanged unless attached to
a [Title of Other Securities].]
	 
	 	 
	[Form of Legend if Warrants are not immediately
exercisable.]

	 	[Prior to                , Warrant evidenced by this
Warrant Certificate cannot be exercised.]






EXERCISABLE ONLY IF COUNTERSIGNED BY THE WARRANT AGENT AS PROVIDED HEREIN

VOID AFTER [          ] P.M., [CITY] TIME, ON                ,








 









 








ARDEA BIOSCIENCES, INC.




WARRANT CERTIFICATE REPRESENTING

WARRANTS TO PURCHASE

COMMON STOCK, PAR VALUE $0.001 PER SHARE



	 	 	 

	No.

	 	Warrants






     This certifies that                or registered assigns is the registered owner of the above
indicated number of Warrants, each Warrant entitling such owner [if Warrants are attached to Other
Securities and are not immediately detachable—, subject to the registered owner qualifying as a
“Holder” of this Warrant Certificate, as hereinafter defined),] to purchase, at any time [after [          ] p.m., [City] time, on            and] on or before [          ] p.m., [City] time, on
          ,            shares of Common Stock, par value $0.001 per share (the “Warrant
Securities”), of Ardea Biosciences, Inc. (the “Company”) on the following basis: during the period
from                , through and including                , the exercise price per Warrant
Security will be $           , subject to adjustment as provided in the Warrant Agreement (as hereinafter
defined) (the “Warrant Price”). The Holder may exercise the Warrants evidenced hereby by providing
certain information set forth on the back hereof and by paying in full, in lawful money of the
United States of America, [in cash or by certified check or official bank check in New York
Clearing House funds] [by bank wire transfer in immediately available funds], the Warrant Price for
each Warrant Security with respect to which this Warrant is exercised to the Warrant Agent (as
hereinafter defined) and by surrendering this Warrant Certificate, with the purchase form on the
back hereof duly executed, at the corporate trust office of [name of Warrant Agent], or its
successor as warrant agent (the “Warrant Agent”), which is, on the date hereof, at the address
specified on the reverse hereof, and upon compliance with and subject to the conditions set forth
herein and in the Warrant Agreement (as hereinafter defined).



     The term “Holder” as used herein shall mean [if Warrants are attached to Other Securities and
are not immediately detachable—prior to                ,                (the “Detachable
Date”), the registered owner of the Company’s [title of Other Securities] to which this Warrant
Certificate was initially attached, and after such Detachable Date,] the person in whose name at
the time this Warrant Certificate shall be registered upon the books to be maintained by the
Warrant Agent for that purpose pursuant to Section 4 of the Warrant Agreement.



     The Warrants evidenced by this Warrant Certificate may be exercised to purchase a whole number
of Warrant Securities in registered form. Upon any exercise of fewer than all of the Warrants
evidenced by this Warrant Certificate, there shall be issued to the Holder hereof a new Warrant
Certificate evidencing Warrants for the number of Warrant Securities remaining unexercised.



     This Warrant Certificate is issued under and in accordance with the Warrant Agreement dated as
of                ,                (the “Warrant Agreement”), between the Company and the
Warrant Agent and is subject to the terms and provisions contained in the Warrant Agreement, to all
of which terms and provisions the Holder of this Warrant Certificate consents by acceptance hereof.
Copies of the Warrant Agreement are on file at the above-mentioned office of the Warrant Agent.



     [If Warrants are attached to Other Securities and are not immediately detachable — Prior to
the Detachable Date, this Warrant Certificate may be exchanged or transferred only together with
the [Title of Other Securities] (the “Other Securities”) to which this Warrant Certificate was
initially attached, and only for the purpose of effecting or in conjunction with, an exchange or
transfer of such Other Security. Additionally, on or prior to the Detachable Date, each transfer of
such Other Security on the register of the Other Securities shall operate also to transfer this
Warrant Certificate. After such date, transfer of this] [If Warrants are attached to Other
Securities and are immediately detachable — Transfer of this] Warrant Certificate may be
registered when this Warrant Certificate is surrendered at the corporate trust office of the
Warrant Agent by the registered owner or such owner’s assigns, in the manner and subject to the
limitations provided in the Warrant Agreement.



     [If Other Securities with Warrants which are not immediately detachable — Except as
provided in the immediately preceding paragraph, after] [If Other Securities with Warrants which
are immediately detachable or Warrants alone — After] countersignature by the Warrant Agent and
prior to the expiration of this Warrant



 









 




Certificate, this Warrant Certificate may be exchanged at the corporate trust office of the Warrant
Agent for Warrant Certificates representing Warrants for the same aggregate number of Warrant
Securities.




     This Warrant Certificate shall not entitle the Holder hereof to any of the rights of a holder
of the Warrant Securities, including, without limitation, the right to receive payments of
dividends or distributions, if any, on the Warrant Securities (except to the extent set forth in
the Warrant Agreement) or to exercise any voting rights.



     Reference is hereby made to the further provisions of this Warrant Certificate set forth on
the reverse hereof, which further provisions shall for all purposes have the same effect as if set
forth at this place.



     This Warrant Certificate shall not be valid or obligatory for any purpose until countersigned
by the Warrant Agent.



     IN WITNESS WHEREOF, the Company has caused this Warrant to be executed in its name and on its
behalf by the facsimile signatures of its duly authorized officers.



Dated:




	 	 	 	 	 
	 	ARDEA BIOSCIENCES, INC. 

 	 
	 	By  	 	 
	 	 	Its 	 	 
	 



Attest:




	 	 	 	 	 
	 	Countersigned: 



As Warrant Agent 

 	 
	 	By  	 	 
	 	 	Authorized Signature 	 
	 	 	 	 



 









 






	 	 	 	 	 



[REVERSE OF WARRANT CERTIFICATE]




(Instructions for Exercise of Warrant)




     To exercise any Warrants evidenced hereby for Warrant Securities (as hereinafter defined), the
Holder must pay, in lawful money of the United States of America, [in cash or by certified check or
official bank check in New York Clearing House funds] [by bank wire transfer in immediately
available funds], the Warrant Price in full for Warrants exercised, to [Warrant Agent] [address of
Warrant Agent], Attn:                , which payment must specify the name of the Holder and the
number of Warrants exercised by such Holder. In addition, the Holder must complete the information
required below and present this Warrant Certificate in person or by mail (certified or registered
mail is recommended) to the Warrant Agent at the appropriate address set forth above. This Warrant
Certificate, completed and duly executed, must be received by the Warrant Agent within five
business days of the payment.



(To be executed upon exercise of Warrants)




     The undersigned hereby irrevocably elects to exercise                Warrants, evidenced by
this Warrant Certificate, to purchase                shares of the Common Stock, par value $0.001
per share (the “Warrant Securities”), of Ardea Biosciences, Inc. and represents that he has
tendered payment for such Warrant Securities, in lawful money of the United States of America, [in
cash or by certified check or official bank check in New York Clearing House funds] [by bank wire
transfer in immediately available funds], to the order of Ardea Biosciences, Inc., c/o [insert name
and address of Warrant Agent], in the amount of $           in accordance with the terms hereof. The
undersigned requests that said Warrant Securities be in fully registered form in the authorized
denominations, registered in such names and delivered all as specified in accordance with the
instructions set forth below.



     If the number of Warrants exercised is less than all of the Warrants evidenced hereby, the
undersigned requests that a new Warrant Certificate evidencing the Warrants for the number of
Warrant Securities remaining unexercised be issued and delivered to the undersigned unless
otherwise specified in the instructions below.



	 	 	 	 	 	 	 

	Dated
	 	 	 	Name	 	 
	 
	 	 	 	 
	 

	 	 	 	 	 	Please Print
	 
	 	 	 	 	 	 
	Address:
	 	 	 	 	 	 
	 
	 	 	 	 	 	 
	 	 	 	 	 
	(Insert Social Security or Other
Identifying Number of Holder)	 	 	 	 
	 
	 	 	 	 	 	 
	Signature 

Guaranteed
	 	 	 	 	 	 
	 

	 	 	 	 	 	 
	 

	 	Signature	 	 	 	 






 









 





(Signature must conform in all respects to name of holder as specified on the face of this Warrant
Certificate and must bear a signature guarantee by a bank, trust company or member broker of the
New York, Midwest or Pacific Stock Exchange).



This Warrant may be exercised at the following addresses:




By hand

at




By mail

at



[Instructions as to form and delivery of Warrant Securities and, if applicable, Warrant Certificates evidencing
Warrants for the number of Warrant Securities remaining unexercised—complete as appropriate.]











 









 








ASSIGNMENT




[Form of assignment to be executed if Warrant Holder desires to transfer Warrant)


FOR VALUE RECEIVED,           hereby sells, assigns and transfers unto:




	 	 	 

	(Please print name and address including zip code)

	 	Please print Social Security or other identifying number





the right represented by the within Warrant to purchase                 shares of [Title of
Warrant Securities] of Ardea Biosciences, Inc. to which the within Warrant relates and appoints
attorney to transfer such right on the books of the Warrant Agent with full
power of substitution in the premises.




	 	 	 	 	 

	Dated

	 	 	 	 
	 

	 	 
	 	 
	 

	 	 	 	Signature






(Signature must conform in all respects to name of holder as specified on the face of the Warrant)



Signature Guaranteed