<PAGE>

                                                                     EXHIBIT 4.3

NEITHER THIS SECURITY NOR THE SECURITIES FOR WHICH THIS SECURITY IS EXERCISABLE
HAVE BEEN REGISTERED WITH THE SECURITIES AND EXCHANGE COMMISSION OR THE
SECURITIES COMMISSION OF ANY STATE IN RELIANCE UPON AN EXEMPTION FROM
REGISTRATION UNDER THE SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES
ACT"), AND, ACCORDINGLY, MAY NOT BE OFFERED OR SOLD EXCEPT PURSUANT TO AN
EFFECTIVE REGISTRATION STATEMENT UNDER THE SECURITIES ACT OR PURSUANT TO AN
AVAILABLE EXEMPTION FROM, OR IN A TRANSACTION NOT SUBJECT TO, THE REGISTRATION
REQUIREMENTS OF THE SECURITIES ACT AND IN ACCORDANCE WITH APPLICABLE STATE
SECURITIES LAWS AS EVIDENCED BY A LEGAL OPINION OF COUNSEL TO THE TRANSFEROR TO
SUCH EFFECT, THE SUBSTANCE OF WHICH SHALL BE REASONABLY ACCEPTABLE TO THE
COMPANY. THIS SECURITY AND THE SECURITIES ISSUABLE UPON EXERCISE OF THIS
SECURITY MAY BE PLEDGED IN CONNECTION WITH A BONA FIDE MARGIN ACCOUNT OR OTHER
LOAN SECURED BY SUCH SECURITIES

                          COMMON STOCK PURCHASE WARRANT

                To Purchase __________ Shares of Common Stock of

                             EPOCH BIOSCIENCES, INC.

Warrant No. W-2004-[ ]              Date of Original Issuance: February 23, 2004

         THIS COMMON STOCK PURCHASE WARRANT CERTIFIES that, for value received,
_____________ (the "Holder"), is entitled, upon the terms and subject to the
limitations on exercise and the conditions hereinafter set forth, at any time on
or after February 23, 2004 (the "Initial Exercise Date") and on or prior to the
close of business on February 23, 2009 (the "Termination Date") but not
thereafter, to subscribe for and purchase from Epoch Biosciences, Inc, a
corporation incorporated in the State of Delaware (the "Company"), up to
____________ shares (the "Warrant Shares") of Common Stock, par value $0.01 per
share, of the Company (the "Common Stock"). The purchase price of one share of
Common Stock (the "Exercise Price") under this Warrant shall be $3.89, subject
to adjustment hereunder. The Exercise Price and the number of Warrant Shares for
which the Warrant is exercisable shall be subject to adjustment as provided
herein. CAPITALIZED TERMS USED AND NOT OTHERWISE DEFINED HEREIN SHALL HAVE THE
MEANINGS SET FORTH IN THAT CERTAIN SECURITIES PURCHASE AGREEMENT (THE "PURCHASE
AGREEMENT"), DATED FEBRUARY 23, 2004, BETWEEN THE COMPANY AND THE PURCHASERS
SIGNATORY THERETO.

         1.       Title to Warrant. Prior to the Termination Date and subject to
compliance with applicable laws and Section 7 of this Warrant, this Warrant and
all rights hereunder are transferable, in whole or in part, at the office or
agency of the Company by the Holder in person or by duly authorized attorney,
upon surrender of this Warrant together with the Assignment Form annexed hereto
properly endorsed. The transferee shall sign an investment letter in form and
substance reasonably satisfactory to the Company.

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

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<PAGE>

         3.       Exercise of Warrant.

                  (a)      Exercise of the purchase rights represented by this
Warrant may be made at any time or times on or after the Initial Exercise Date
and on or before the Termination Date by the surrender of the Notice of Exercise
Form annexed hereto duly executed, at the office of the Company (or such other
office or agency of the Company as it may designate by notice in writing to the
registered Holder at the address of such Holder appearing on the books of the
Company) and upon payment of the Exercise Price of the shares thereby purchased
by wire transfer or cashier's check drawn on a United States bank or by means of
a cashless exercise pursuant to Section 3(d), the Holder shall be entitled to
receive a certificate for the number of Warrant Shares so purchased. The Holder
shall not be required to deliver the original Warrant in order to effect an
exercise hereunder. Execution and delivery of the Exercise Notice shall have the
same effect as cancellation of the original Warrant and issuance of a New
Warrant evidencing the right to purchase the remaining number of Warrant Shares,
provided that the Holder delivers the original Warrant for cancellation or
reissuance within five Trading Days of the delivery of the Notice of Exercise
Form. Certificates for shares purchased hereunder shall be delivered to the
Holder within three (3) Trading Days after the date on which this Warrant shall
have been exercised as aforesaid. This Warrant shall be deemed to have been
exercised and such certificate or certificates shall be deemed to have been
issued, and the Holder or any other person so designated to be named therein
shall be deemed to have become a holder of record of such shares for all
purposes, as of the date the Warrant has been exercised by payment to the
Company of the Exercise Price and all taxes required to be paid by the Holder,
if any, pursuant to Section 5 prior to the issuance of such shares, have been
paid. If the Company fails to deliver to the Holder a certificate or
certificates representing the Warrant Shares pursuant to this Section 3(a) by
the close of business on the third Trading Day after the date of exercise, then
the Holder will have the right to rescind such exercise. In addition to any
other rights available to the Holder, if the Company fails to deliver to the
Holder a certificate or certificates representing the Warrant Shares pursuant to
an exercise by the close of business on the third Trading Day after the date of
exercise, and if after such third Trading Day the Holder purchases (in an open
market transaction or otherwise) shares of Common Stock to deliver in
satisfaction of a sale by the Holder of the Warrant Shares which the Holder
anticipated receiving upon such exercise (a "Buy-In"), then the Company shall
(1) pay in cash to the Holder the amount by which (x) the Holder's total
purchase price (including brokerage commissions, if any) for the shares of
Common Stock so purchased exceeds (y) the amount obtained by multiplying (A) the
number of Warrant Shares that the Company was required to deliver to the Holder
in connection with the exercise at issue times (B) the price at which the sell
order giving rise to such purchase obligation was executed, and (2) at the
option of the Holder, either reinstate the portion of the Warrant and equivalent
number of Warrant Shares for which such exercise was not honored or deliver to
the Holder the number of shares of Common Stock that would have been issued had
the Company timely complied with its exercise and delivery obligations
hereunder. For example, if the Holder purchases Common Stock having a total
purchase price of $11,000 to cover a Buy-In with respect to an attempted
exercise of shares of Common Stock with an aggregate sale price giving rise to
such purchase obligation of $10,000, under clause (1) of the immediately
preceding sentence the Company shall be required to pay the Holder $1,000. The
Holder shall provide the Company written notice indicating the amounts payable
to the Holder in respect of the Buy-In, together with applicable confirmations
and other evidence reasonably requested by the Company. The Company's
obligations to issue and deliver Warrant Shares in accordance with the terms
hereof are absolute and unconditional, irrespective of any action or inaction by
the Holder to enforce the same, any waiver or consent with respect to any
provision

                                       2
<PAGE>

hereof, the recovery of any judgment against any Person or any action to enforce
the same, or any setoff, counterclaim, recoupment, limitation or termination, or
any breach or alleged breach by the Holder or any other Person of any obligation
to the Company or any violation or alleged violation of law by the Holder or any
other Person, and irrespective of any other circumstance which might otherwise
limit such obligation of the Company to the Holder in connection with the
issuance of Warrant Shares. Nothing herein shall limit a Holder's right to
pursue any other remedies available to it hereunder, at law or in equity
including, without limitation, a decree of specific performance and/or
injunctive relief with respect to the Company's failure to timely deliver
certificates representing shares of Common Stock upon exercise of the Warrant as
required pursuant to the terms hereof.

                  (b)      If this Warrant shall have been exercised in part,
the Company shall, at the time of delivery of the certificate or certificates
representing Warrant Shares, deliver to Holder a new Warrant evidencing the
rights of Holder to purchase the unpurchased Warrant Shares called for by this
Warrant, which new Warrant shall in all other respects be identical with this
Warrant.

                  (c)      Notwithstanding anything to the contrary contained
herein, the number of shares of Common Stock that may be acquired by the Holder
upon any exercise of this Warrant (or otherwise in respect hereof) shall be
limited to the extent necessary to insure that, following such exercise (or
other issuance), the total number of shares of Common Stock then beneficially
owned by such Holder and its Affiliates and any other Persons whose beneficial
ownership of Common Stock would be aggregated with the Holder's for purposes of
Section 13(d) of the Exchange Act, does not exceed 4.999% (the "MAXIMUM
PERCENTAGE") of the total number of issued and outstanding shares of Common
Stock (including for such purpose the shares of Common Stock issuable upon such
exercise). For such purposes, beneficial ownership shall be determined in
accordance with Section 13(d) of the Exchange Act and the rules and regulations
promulgated thereunder. Each delivery of an Exercise Notice hereunder will
constitute a representation by the Holder that it has evaluated the limitation
set forth in this paragraph and determined that issuance of the full number of
Warrant Shares requested in such Exercise Notice is permitted under this
paragraph. The Company's obligation to issue shares of Common Stock in excess of
the limitation referred to in this Section shall be suspended (and shall not
terminate or expire notwithstanding any contrary provisions hereof) until such
time, if any, as such shares of Common Stock may be issued in compliance with
such limitation. By written notice to the Company, the Holder may waive the
provisions of this Section or increase or decrease the Maximum Percentage to any
other percentage specified in such notice, but (i) any such waiver or increase
will not be effective until the 61st day after such notice is delivered to the
Company, and (ii) any such waiver or increase or decrease will apply only to the
Holder and not to any other holder of Warrants.

                  (d)      If, but only if, at any time after one (1) year from
the date of issuance of this Warrant there is no effective Registration
Statement registering the resale of the Warrant Shares by the Holder, this
Warrant may also be exercised by means of a "cashless exercise" in which the
Holder shall be entitled to receive a certificate for the number of Warrant
Shares equal to the quotient obtained by dividing [(A-B) (X)] by (A), where:

                           (A) = the Closing Price on the Trading Day preceding
                           the date of such election;

                           (B) = the Exercise Price of the Warrants, as
                           adjusted; and

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<PAGE>

                           (X) = the number of Warrant Shares issuable upon
                           exercise of the Warrants in accordance with the terms
                           of this Warrant.

         For purposes of Rule 144 promulgated under the Securities Act, it is
intended, understood and acknowledged that the Warrant Shares issued in a
cashless exercise transaction shall be deemed to have been acquired by the
Holder, and the holding period for the Warrant Shares shall be deemed to have
commenced, on the date this Warrant was originally issued pursuant to the
Purchase Agreement.

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

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

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

         7.       Transfer, Division and Combination.

                  (a)      Subject to compliance with any applicable securities
laws and the conditions set forth in Sections 1 and 7(e) hereof and to the
provisions of Section 4.1 of the Purchase Agreement, this Warrant and all rights
hereunder are transferable, in whole or in part, so long as the amount of
Warrant Shares transferred is either (i) equal to at least 10,000 shares (as
adjusted for any stock splits, stock combinations, stock dividends and other
similar events), or (ii) the total amount then held by such Holder (in each
case, on an as-exercised basis), upon surrender of this Warrant at the principal
office of the Company, together with a written assignment of this Warrant
substantially in the form attached hereto duly executed by the Holder or its
agent or attorney and funds sufficient to pay any transfer taxes payable upon
the making of such transfer. Upon such surrender and, if required, such payment,
the Company shall execute and deliver a new Warrant or Warrants in the name of
the assignee or assignees and in the denomination or denominations specified in
such instrument of assignment, and shall issue to the assignor a new Warrant
evidencing the portion of this Warrant not so assigned, and this Warrant shall
promptly be cancelled. A Warrant, if properly assigned, may be exercised by a
new holder for the purchase of Warrant Shares without having a new Warrant
issued.

                  (b)      This Warrant may be divided or combined with other
Warrants upon presentation hereof at the aforesaid office of the Company,
together with a written notice specifying

                                       4
<PAGE>

the names and denominations in which new Warrants are to be issued, signed by
the Holder or its agent or attorney. Subject to compliance with Section 7(a), as
to any transfer which may be involved in such division or combination, the
Company shall execute and deliver a new Warrant or Warrants in exchange for the
Warrant or Warrants to be divided or combined in accordance with such notice.

                  (c)      The Company shall prepare, issue and deliver at its
own expense (other than transfer taxes) the new Warrant or Warrants under this
Section 7.

                  (d)      The Company agrees to maintain, at its aforesaid
office, books for the registration and the registration of transfer of the
Warrants.

                  (e)      If, at the time of the surrender of this Warrant in
connection with any transfer of this Warrant, the transfer of this Warrant shall
not be registered pursuant to an effective registration statement under the
Securities Act and under applicable state securities or blue sky laws, the
Company may require, as a condition of allowing such transfer (i) that the
Holder or transferee of this Warrant, as the case may be, furnish to the Company
a written opinion of counsel (which opinion shall be in form, substance and
scope customary for opinions of counsel in comparable transactions) to the
effect that such transfer may be made without registration under the Securities
Act and under applicable state securities or blue sky laws, (ii) that the holder
or transferee execute and deliver to the Company an investment letter in form
and substance acceptable to the Company and (iii) that the transferee be an
"accredited investor" as defined in Rule 501(a) promulgated under the Securities
Act.

         8.       No Rights as Shareholder until Exercise. This Warrant does not
entitle the Holder to any voting rights or other rights as a shareholder of the
Company prior to the exercise hereof. Upon the surrender of this Warrant and the
payment of the aggregate Exercise Price (or by means of a cashless exercise),
the Warrant Shares so purchased shall be and be deemed to be issued to such
Holder as the record owner of such shares as of the close of business on the
later of the date of such surrender or payment.

         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 and Splits. If the Company, at any
time while this Warrant is outstanding, (i) pays a stock dividend on its Common
Stock or otherwise makes a distribution on any class of capital stock that is
payable in shares of Common Stock, (ii) subdivides outstanding shares of Common
Stock into a larger number of shares, or (iii) 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 of which the numerator shall be
the number of shares of Common Stock outstanding immediately before such event
and of which the denominator shall be the number of shares of Common Stock
outstanding immediately after such event. Any adjustment made pursuant to clause
(i) of this paragraph shall become effective immediately after the record date
for the determination of stockholders entitled to receive such dividend or
distribution, and any adjustment pursuant to clause (ii) or (iii) of this
paragraph shall become effective immediately after the effective date of such
subdivision or combination.

                                       5
<PAGE>

                  (b)      Pro Rata Distributions. If the Company, at any time
while this Warrant is outstanding, distributes to holders of Common Stock (i)
evidences of its indebtedness, (ii) any security (other than a distribution of
Common Stock covered by the preceding paragraph), (iii) rights or warrants to
subscribe for or purchase any security, or (iv) any other asset (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 shall be adjusted (effective on such
record date) to equal the product of such Exercise Price times a fraction of
which the denominator shall be the average of the Closing Prices for the five
Trading Days immediately prior to (but not including) such record date and of
which the numerator shall be such average less the then fair market value of the
Distributed Property distributed in respect of one outstanding share of Common
Stock, as determined by the Company's independent certified public accountants
that regularly examine the financial statements of the Company (an "APPRAISER").
In such event, the Holder, after receipt of the determination by the Appraiser,
shall have the right to select an additional appraiser (which shall be a
nationally recognized accounting firm), in which case such fair market value
shall be deemed to equal the average of the values determined by each of the
Appraiser and such appraiser. As an alternative to the foregoing adjustment to
the Exercise Price, at the request of the Holder delivered before the 90th day
after such record date, the Company will deliver to such Holder, within five
Trading Days after such request (or, if later, on the effective date of such
distribution), the Distributed Property that such Holder would have been
entitled to receive in respect of the Warrant Shares for which this Warrant
could have been exercised immediately prior to such record date. If such
Distributed Property is not delivered to a Holder pursuant to the preceding
sentence, then upon expiration of or any exercise of this Warrant that occurs
after such record date, such Holder shall remain entitled to receive, in
addition to the Warrant Shares otherwise issuable upon such exercise (if
applicable), such Distributed Property.

                  (c)      Fundamental Transactions. If, at any time while this
Warrant is outstanding, (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, (iii) any tender offer or exchange offer (whether by the Company
or another Person) is completed pursuant to which holders of Common Stock are
permitted to tender or exchange their shares for other securities, cash or
property, or (iv) the Company effects any reclassification of the Common Stock
or any compulsory share exchange pursuant to which the Common Stock is
effectively converted into or exchanged for other securities, cash or property
(other than as a result of a subdivision or combination of shares of Common
Stock covered by Section 9(a) above) (in any such case, a "FUNDAMENTAL
TRANSACTION"), then the Holder shall have the right thereafter to receive, upon
exercise of this Warrant, the same amount and kind of securities, cash or
property as it would have been entitled to receive upon the occurrence of such
Fundamental Transaction if it had been, immediately prior to such Fundamental
Transaction, the holder of the number of Warrant Shares then issuable upon
exercise in full of this Warrant (the "ALTERNATE CONSIDERATION"). The aggregate
Exercise Price for this Warrant will not be affected by any such Fundamental
Transaction, but the Company shall apportion such aggregate Exercise Price among
the Alternate Consideration in a reasonable manner reflecting the relative value
of any different components of the Alternate Consideration. If holders of Common
Stock are given any choice as to the securities, cash or property to be received
in a Fundamental Transaction, then the Holder shall be given the same choice as
to the Alternate Consideration it receives upon any exercise of this Warrant
following such Fundamental Transaction. At the Holder's request, any successor
to the Company or surviving entity in such Fundamental Transaction shall issue
to the Holder a new warrant consistent with the

                                       6
<PAGE>

foregoing provisions and evidencing the Holder's right to purchase the Alternate
Consideration for the aggregate Exercise Price upon exercise thereof. The terms
of any agreement pursuant to which a Fundamental Transaction is effected shall
include terms requiring any such successor or surviving entity to comply with
the provisions of this paragraph (c) and insuring that this Warrant (or any such
replacement security) will be similarly adjusted upon any subsequent transaction
analogous to a Fundamental Transaction. If any Fundamental Transaction
constitutes or results in a Change of Control (other than an acquisition of the
Company solely for shares that are publicly traded on a Trading Market, in which
event the Holder shall be entitled to a "like-kind warrant" as described above),
then at the request of the Holder delivered before the 90th day after such
Fundamental Transaction, the Company (or any such successor or surviving entity)
will purchase this Warrant from the Holder for a purchase price, payable in cash
within five Trading Days after such request (or, if later, on the effective date
of the Fundamental Transaction), equal to the Black-Scholes value of the
remaining unexercised portion of this Warrant on the date of such request (it
being understood that in calculating the Black-Scholes value, the "volatility"
shall be the lesser of the historical volatility of the prior 365 day period, or
50%).

                  (d)      Subsequent Equity Sales.

                           (i)      If, at any time while this Warrant is
         outstanding, the Company or any Subsidiary issues additional shares of
         Common Stock or rights, warrants, options or other securities or debt
         convertible, exercisable or exchangeable for shares of Common Stock or
         otherwise entitling any Person to acquire shares of Common Stock
         (collectively, "COMMON STOCK EQUIVALENTS") at an effective net price to
         the Company per share of Common Stock (the "EFFECTIVE PRICE") less than
         the lesser of (i) $2.50 (as adjusted for any stock splits, stock
         combinations, stock dividends and other similar events) or (ii) the
         Exercise Price (as adjusted hereunder to such date), then the Exercise
         Price shall be reduced to equal the product of (A) the Exercise Price
         in effect immediately prior to such issuance of Common Stock or Common
         Stock Equivalents times (B) a fraction, the numerator of which is the
         sum of (1) the number of shares of Common Stock outstanding immediately
         prior to such issuance, plus (2) the number of shares of Common Stock
         which the aggregate Effective Price of the Common Stock issued (or
         deemed to be issued) would purchase at the Adjustment Price, and the
         denominator of which is the aggregate number of shares of Common Stock
         outstanding or deemed to be outstanding immediately after such
         issuance. For purposes of this paragraph, in connection with any
         issuance of any Common Stock Equivalents, (A) the maximum number of
         shares of Common Stock potentially issuable at any time upon
         conversion, exercise or exchange of such Common Stock Equivalents (the
         "DEEMED NUMBER") shall be deemed to be outstanding upon issuance of
         such Common Stock Equivalents, (B) the Effective Price applicable to
         such Common Stock shall equal the minimum dollar value of consideration
         payable to the Company to purchase such Common Stock Equivalents and to
         convert, exercise or exchange them into Common Stock (net of any
         discounts, fees, commissions and other expenses), divided by the Deemed
         Number, and (C) no further adjustment shall be made to the Exercise
         Price upon the actual issuance of Common Stock upon conversion,
         exercise or exchange of such Common Stock Equivalents.

                           (ii)     If, at any time while this Warrant is
         outstanding, the Company or any Subsidiary issues Common Stock
         Equivalents with an Effective Price or a number of underlying shares
         that floats or resets or otherwise varies or is subject to adjustment
         based (directly or indirectly) on market prices of the Common Stock (a
         "FLOATING PRICE SECURITY"),

                                       7
<PAGE>


         then for purposes of applying the preceding paragraph in connection
         with any subsequent exercise, the Effective Price will be determined
         separately on each Exercise Date and will be deemed to equal the lowest
         Effective Price at which any holder of such Floating Price Security is
         entitled to acquire Common Stock on such Exercise Date (regardless of
         whether any such holder actually acquires any shares on such date).

                           (iii)    Notwithstanding the foregoing, no adjustment
         will be made under this paragraph (d) in respect of any Excluded Stock.

                   (iv)     In the event that any Holder's receipt of shares of
         Common Stock upon exercise of this Warrant would require stockholder
         approval under applicable Trading Market rules, then, the Company shall
         use commercially reasonable best efforts to obtain the required
         stockholder approval necessary to permit the issuance of such shares as
         soon as is reasonably possible. No shares of Common Stock that were
         issued pursuant to the Transaction Documents may be entitled to vote to
         approve the issuance of such Excess Shares. No shares may be issued in
         excess of such amount without such required stockholder approval.

                  (e)      Number of Warrant Shares. Simultaneously with any
adjustment to the Exercise Price pursuant to paragraphs (a), (b) or (d) of this
Section, 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 in effect immediately prior to such adjustment.

                  (f)      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.

                  (g)      Notice of Adjustments. Upon the occurrence of each
adjustment pursuant to this Section 9, the Company at its expense will promptly
compute such adjustment in accordance with the terms of this Warrant and prepare
a certificate setting forth such adjustment, including a statement of the
adjusted Exercise Price and adjusted number or type of Warrant Shares or other
securities issuable upon exercise of this Warrant (as applicable), describing
the transactions giving rise to such adjustments and showing in detail the facts
upon which such adjustment is based. Upon written request, the Company will
promptly deliver a copy of each such certificate to the Holder and to the
Company's Transfer Agent.

         10.      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 generally to its holders of common stock to subscribe for or
purchase any capital stock of the Company or any Subsidiary, (ii) authorizes or
approves, enters into 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

                                       8
<PAGE>

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 insure 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.

         11.      Loss, Theft, Destruction or Mutilation of Warrant. The Company
covenants that upon receipt by the Company of evidence reasonably satisfactory
to it of the loss, theft, destruction or mutilation of this Warrant or any stock
certificate relating to the Warrant Shares, and in case of loss, theft or
destruction, of indemnity or security reasonably satisfactory to it and upon
surrender and cancellation of such Warrant or stock certificate, if mutilated,
the Company will make and deliver a new Warrant or stock certificate of like
tenor and dated as of such cancellation, in lieu of such Warrant or stock
certificate.

         12.      Saturdays, Sundays, Holidays, etc. If the last or appointed
day for the taking of any action or the expiration of any right required or
granted herein shall be a Saturday, Sunday or a legal holiday, then such action
may be taken or such right may be exercised on the next succeeding day not a
Saturday, Sunday or legal holiday.

         13.      Voluntary Adjustment by the Company. The Company may at any
time during the term of this Warrant reduce the then current Exercise Price to
any amount and for any period of time deemed appropriate by the Board of
Directors of the Company.

         14.      Authorized Shares. The Company covenants that during the
period the Warrant is outstanding, it will reserve from its authorized and
unissued Common Stock a sufficient number of shares to provide for the issuance
of the Warrant Shares upon the exercise of any purchase rights under this
Warrant. The Company further covenants that its issuance of this Warrant shall
constitute full authority to its officers who are charged with the duty of
executing stock certificates to execute and issue the necessary certificates for
the Warrant Shares upon the exercise of the purchase rights under this Warrant.
The Company will take all such reasonable action as may be necessary to assure
that such Warrant Shares may be issued as provided herein without violation of
any applicable law or regulation, or of any requirements of the Trading Market
upon which the Common Stock may be listed.

         Except and to the extent as waived or consented to by the Holder, the
Company shall not by any action, including, without limitation, amending its
certificate of incorporation 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 actions as may be
necessary or appropriate to protect the rights of Holder as set forth in this
Warrant against impairment. Without limiting the generality of the foregoing,
the Company will (a) not increase the par value of any Warrant Shares above the
amount payable therefor upon such exercise immediately prior to such increase in
par value, (b) take all such action as may be necessary or appropriate in order
that the Company may validly and legally issue fully paid and nonassessable
Warrant Shares upon the exercise of this Warrant, and (c) use commercially
reasonable efforts to obtain all such authorizations, exemptions or consents
from any public

                                       9
<PAGE>

regulatory body having jurisdiction thereof as may be necessary to enable the
Company to perform its obligations under this Warrant.

         Before taking any action which would result in an adjustment in the
number of Warrant Shares for which this Warrant is exercisable or in the
Exercise Price, the Company shall obtain all such authorizations or exemptions
thereof, or consents thereto, as may be necessary from any public regulatory
body or bodies having jurisdiction thereof.

         15.      Miscellaneous.

                  (a)      Jurisdiction. All questions concerning the
construction, validity, enforcement and interpretation of this Warrant shall be
determined in accordance with the provisions of the Purchase Agreement.

                  (b)      Restrictions. The Holder acknowledges that the
Warrant Shares acquired upon the exercise of this Warrant, if not registered,
will have restrictions upon resale imposed by state and federal securities laws.

                  (c)      Nonwaiver and Expenses. No course of dealing or any
delay or failure to exercise any right hereunder on the part of Holder shall
operate as a waiver of such right or otherwise prejudice Holder's rights, powers
or remedies, notwithstanding all rights hereunder terminate on the Termination
Date. If the Company willfully and knowingly fails to comply with any provision
of this Warrant, which results in any material damages to the Holder, the
Company shall pay to Holder such amounts as shall be sufficient to cover any
costs and expenses including, but not limited to, reasonable attorneys' fees,
including those of appellate proceedings, incurred by Holder in collecting any
amounts due pursuant hereto or in otherwise enforcing any of its rights, powers
or remedies hereunder.

                  (d)      Notices. Any notice, request or other document
required or permitted to be given or delivered to the Holder by the Company
shall be delivered in accordance with the notice provisions of the Purchase
Agreement; provided upon any permitted assignment of this Warrant, the assignee
shall promptly provide the Company with its contact information.

                  (e)      Limitation of Liability. No provision hereof, in the
absence of any affirmative action by Holder to exercise this Warrant or purchase
Warrant Shares, and no enumeration herein of the rights or privileges of Holder,
shall give rise to any liability of Holder for the purchase price of any Common
Stock or as a stockholder of the Company, whether such liability is asserted by
the Company or by creditors of the Company.

                  (f)      Remedies. Holder, in addition to being entitled to
exercise all rights granted by law, including recovery of damages, will be
entitled to specific performance of its rights under this Warrant. The Company
agrees that monetary damages would not be adequate compensation for any loss
incurred by reason of a breach by it of the provisions of this Warrant and
hereby agrees to waive the defense in any action for specific performance that a
remedy at law would be adequate.

                  (g)      Successors and Assigns. Subject to applicable
securities laws, this Warrant and the rights and obligations evidenced hereby
shall inure to the benefit of and be binding upon the successors of the Company
and the successors and permitted assigns of Holder. The provisions of

                                       10
<PAGE>

this Warrant are intended to be for the benefit of all Holders from time to time
of this Warrant and shall be enforceable by any such Holder or holder of Warrant
Shares.

                  (h)      Amendment. This Warrant may be modified or amended or
the provisions hereof waived with the written consent of the Company and the
Holder.

                  (i)      Severability. Wherever possible, each provision of
this Warrant shall be interpreted in such manner as to be effective and valid
under applicable law, but if any provision of this Warrant shall be prohibited
by or invalid under applicable law, such provision shall be ineffective to the
extent of such prohibition or invalidity, without invalidating the remainder of
such provisions or the remaining provisions of this Warrant.

                  (j)      Headings. The headings used in this Warrant are for
the convenience of reference only and shall not, for any purpose, be deemed a
part of this Warrant.

                              ********************

                                       11
<PAGE>

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

Dated: February 23, 2004

                                          EPOCH BIOSCIENCES, INC.

                                          By: __________________________________
                                                 Name:
                                                 Title:

                                       12
<PAGE>

                               NOTICE OF EXERCISE

To:      Epoch Biosciences, Inc.

         (1)      The undersigned hereby elects to purchase ________ Warrant
Shares of Epoch Biosciences, Inc. pursuant to the terms of the attached Warrant
(only if exercised in full), and tenders herewith payment of the exercise price
in full, together with all applicable transfer taxes, if any.

         (2)      Payment shall take the form of (check applicable box):

                  [ ] in lawful money of the United States; or.

                  [ ] the cancellation of such number of Warrant Shares as is
                      necessary, in accordance with the formula set forth in
                      subsection 3(d), to exercise this Warrant with respect to
                      the maximum number of Warrant Shares purchasable pursuant
                      to the cashless exercise procedure set forth in subsection
                      3(d).

         (3)      Please issue a certificate or certificates representing said
Warrant Shares in the name of the undersigned or in such other name as is
specified below:

                  _______________________________

The Warrant Shares shall be delivered to the following:

                  _______________________________

                  _______________________________

                  _______________________________

         (4)      Accredited Investor. The undersigned is an "accredited
investor" as defined in Regulation D promulgated under the Securities Act of
1933, as amended.

                                                [PURCHASER]

                                                By: ____________________________
                                                      Name:
                                                      Title:

                                                Dated: _________________________

<PAGE>

                                 ASSIGNMENT FORM

                    (To assign the foregoing warrant, execute
                   this form and supply required information.
                 Do not use this form to exercise the warrant.)

         FOR VALUE RECEIVED, the foregoing Warrant and all rights evidenced
thereby are hereby assigned to

_______________________________________________ whose address is

_________________________________________________________________.

_________________________________________________________________

                                                Dated: ______________, _______

                           Holder's Signature:_____________________________

                           Holder's Address:  _____________________________

                                              _____________________________

Signature Guaranteed: ___________________________________________

NOTE: The signature to this Assignment Form must correspond with the name as it
appears on the face of the Warrant, without alteration or enlargement or any
change whatsoever, and must be guaranteed by a bank or trust company. Officers
of corporations and those acting in a fiduciary or other representative capacity
should file proper evidence of authority to assign the foregoing Warrant.