<PAGE>

                                                                    EXHIBIT 10.6

                     FORM OF 4.25% CONVERTIBLE SUBORDINATED
                             NOTE DUE JULY 1, 2008

                                 [FORM OF FACE]

         [THE FOLLOWING LEGEND (THE "RESTRICTED SECURITIES LEGEND") SHALL APPEAR
ON THE FACE OF EACH RESTRICTED SECURITY:

THIS NOTE AND ANY COMMON STOCK ISSUABLE UPON THE CONVERSION OF THIS NOTE HAVE
NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE
"SECURITIES ACT"), AND MAY NOT BE SOLD OR OTHERWISE TRANSFERRED IN THE ABSENCE
OF SUCH REGISTRATION OR AN APPLICABLE EXEMPTION THEREFROM. EACH PURCHASER OF
THIS NOTE IS HEREBY NOTIFIED THAT THE SELLER OF THIS NOTE MAY BE RELYING ON THE
EXEMPTION FROM THE PROVISIONS OF SECTION 5 OF THE SECURITIES ACT PROVIDED BY
RULE 144A THEREUNDER.

THIS NOTE AND ANY COMMON STOCK ISSUABLE UPON CONVERSION OF THIS NOTE MAY NOT BE
OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT (A) (1) TO A PERSON WHO
THE TRANSFEROR REASONABLY BELIEVES IS A QUALIFIED INSTITUTIONAL BUYER WITHIN THE
MEANING OF RULE 144A UNDER THE SECURITIES ACT ACQUIRING FOR ITS OWN ACCOUNT OR
THE ACCOUNT OF A QUALIFIED INSTITUTIONAL BUYER IN A TRANSACTION MEETING THE
REQUIREMENTS OF RULE 144A, (2) PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER
THE SECURITIES ACT PROVIDED BY RULE 144 THEREUNDER (IF AVAILABLE), (3) TO AN
INSTITUTIONAL INVESTOR THAT IS AN "ACCREDITED INVESTOR" WITHIN THE MEANING OF
RULE 501(A)(1), (2), (3) OR (7) OF REGULATION D UNDER THE SECURITIES ACT
PURSUANT TO AN EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT (IF
AVAILABLE) OR (4) PURSUANT TO AN EFFECTIVE REGISTRATION STATEMENT UNDER THE
SECURITIES ACT, AND (B) IN ACCORDANCE WITH ALL APPLICABLE SECURITIES LAWS OF THE
STATES OF THE UNITED STATES AND OTHER JURISDICTIONS.

THIS NOTE, ANY SHARES OF COMMON STOCK ISSUABLE UPON ITS CONVERSION AND ANY
RELATED DOCUMENTATION MAY BE AMENDED OR SUPPLEMENTED FROM TIME TO TIME TO MODIFY
THE RESTRICTIONS ON RESALES AND OTHER TRANSFERS OF THIS NOTE AND ANY SUCH SHARES
TO REFLECT ANY CHANGE IN APPLICABLE LAW OR REGULATION (OR THE INTERPRETATION
THEREOF) OR IN PRACTICES RELATING TO THE RESALE OR TRANSFER OF RESTRICTED
SECURITIES GENERALLY. THE HOLDER OF THIS NOTE AND ANY SUCH SHARES SHALL BE
DEEMED BY THE ACCEPTANCE OF THIS NOTE AND ANY SUCH SHARES TO HAVE AGREED TO ANY
SUCH AMENDMENT OR SUPPLEMENT.]

         [THE FOLLOWING LEGEND SHALL APPEAR ON THE FACE OF EACH GLOBAL SECURITY:

<PAGE>

THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE
HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME OF THE DEPOSITARY OR A
NOMINEE OF THE DEPOSITARY, WHICH MAY BE TREATED BY THE COMPANY, THE TRUSTEE AND
ANY AGENT THEREOF AS OWNER AND HOLDER OF THIS SECURITY FOR ALL PURPOSES.

UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO THE COMPANY OR ITS
AGENT FOR REGISTRATION OF TRANSFER, EXCHANGE OR PAYMENT, AND ANY CERTIFICATE
ISSUED IS REGISTERED IN THE NAME OF CEDE & CO. OR IN SUCH OTHER NAME AS IS
REQUESTED BY AN AUTHORIZED REPRESENTATIVE OF DTC (AND ANY PAYMENT IS MADE TO
CEDE & CO. OR TO SUCH OTHER ENTITY AS IS REQUESTED BY AN AUTHORIZED
REPRESENTATIVE OF DTC), ANY TRANSFER, PLEDGE OR OTHER USE HEREOF FOR VALUE OR
OTHERWISE BY OR TO ANY PERSON IS WRONGFUL INASMUCH AS THE REGISTERED OWNER
HEREOF, CEDE & CO., HAS AN INTEREST HEREIN.

UNLESS AND UNTIL IT IS EXCHANGED IN WHOLE OR IN PART FOR SECURITIES IN
DEFINITIVE REGISTERED FORM IN THE LIMITED CIRCUMSTANCES REFERRED TO IN THE
INDENTURE, THIS GLOBAL SECURITY MAY NOT BE TRANSFERRED EXCEPT AS A WHOLE BY THE
DEPOSITARY TO A NOMINEE OF THE DEPOSITARY OR BY A NOMINEE OF THE DEPOSITARY TO
THE DEPOSITARY OR ANOTHER NOMINEE OF THE DEPOSITARY OR BY THE DEPOSITARY OR ANY
SUCH NOMINEE TO A SUCCESSOR DEPOSITARY OR A NOMINEE OF SUCH SUCCESSOR
DEPOSITARY.]

<PAGE>

                               CORIXA CORPORATION

              4.25% CONVERTIBLE SUBORDINATED NOTE DUE JULY 1, 2008

No. _______________________                                   $ ________________

CUSIP NO. [__________]

         CORIXA CORPORATION, a corporation duly organized and existing under the
laws of the State of Delaware (herein called the "Company", which term includes
any successor Person under the Indenture referred to on the reverse hereof), for
value received, hereby promises to pay to _________________, or registered
assigns, the principal sum of ________ United States Dollars (U.S.$______ )
(which principal amount may from time to time be increased or decreased to such
other principal amounts (which, taken together with the principal amounts of all
other Outstanding Securities, shall not exceed $85,000,000 by adjustments made
on the records of the Trustee hereinafter referred to in accordance with the
Indenture) on July 1, 2008 and to pay interest thereon, from June 13, 2003, or
from the most recent Interest Payment Date (as defined below) to which interest
has been paid or duly provided for, semi-annually in arrears on January 1 and
July 1 in each year (each, an "Interest Payment Date"), commencing January 1,
2004, at the rate of 4.25% per annum, until the principal hereof is due, and at
the rate of 4.25% per annum on any overdue principal and premium, if any, and,
to the extent permitted by law, on any overdue interest. The interest so
payable, and punctually paid or duly provided for, on any Interest Payment Date
will, as provided in the Indenture, be paid to the Person in whose name this
Security (or one or more Predecessor Securities) is registered at the close of
business on the Regular Record Date for such interest, which shall be the
December 15 or June 15 (whether or not a Business Day), as the case may be, next
preceding such Interest Payment Date. Except as otherwise provided in the
Indenture, any such interest not so punctually paid or duly provided for will
forthwith cease to be payable to the Holder on such Regular Record Date and may
either be paid to the Person in whose name this Security (or one or more
Predecessor Securities) is registered at the close of business on a Special
Record Date for the payment of such Defaulted Interest to be fixed by the
Company, notice whereof shall be given to Holders of Securities not less than 10
days prior to the Special Record Date, or be paid at any time in any other
lawful manner not inconsistent with the requirements of any automated quotation
system or securities exchange on which the Securities may be quoted or listed,
and upon such notice as may be required by such exchange, all as more fully
provided in the Indenture. Payments of principal shall be made upon the
surrender of this Security at the option of the Holder at the Corporate Trust
Office of the Trustee, or at such other office or agency of the Company as may
be designated by it for such purpose in the Borough of Manhattan, The City of
New York, in such lawful monies of the United States of America as at the time
of payment shall be legal tender for the payment of public and private debts, or
at such other offices or agencies as the Company may designate, by United States
Dollar check drawn on, or wire transfer to, a United States Dollar account (such
a transfer to be made only to a Holder of an aggregate principal amount of
Securities in excess of U.S.$2,000,000 and only if such Holder shall have
furnished wire instructions in writing to the Trustee no later than 15 days
prior to the relevant payment date). Payment of interest on this Security may be
made by United States Dollar check mailed to the address of the Person entitled
thereto as such address shall appear in the Security Register, or, upon written
application by the Holder to the Security Registrar setting forth wire
instructions not later than the relevant Record

<PAGE>

Date, by transfer to a United States Dollar account (such a transfer to be made
only to a Holder of an aggregate principal amount of Securities in excess of
U.S.$2,000,000 and only if such Holder shall have furnished wire instructions in
writing to the Trustee no later than 15 days prior to the relevant payment
date).

         Except as specifically provided herein and in the Indenture, the
Company shall not be required to make any payment with respect to any tax,
assessment or other governmental charge imposed by any government or any
political subdivision or taxing authority thereof or therein.

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

         Unless the certificate of authentication hereon has been executed by
the Trustee referred to on the reverse hereof or an Authenticating Agent by the
manual signature of one of their respective authorized signatories, this
Security shall not be entitled to any benefit under the Indenture or be valid or
obligatory for any purpose.

<PAGE>

IN WITNESS WHEREOF, the Company has caused this Security to be duly executed.

                                        CORIXA CORPORATION,

                                        By: ____________________________________

                                        Name: Michelle Burris
                                        Title: Chief Financial Officer
Attest:

By: _________________________________________________

Name: Kathleen N. McKereghan
Title: Secretary

TRUSTEE'S CERTIFICATE OF AUTHENTICATION

This is one of the Securities referred to in the within-mentioned Indenture.
Dated:

WELLS FARGO BANK,
NATIONAL ASSOCIATION,
as Trustee

By: _________________________________________________

         Authorized Signatory

<PAGE>

                                [FORM OF REVERSE]

         This Security is one of a duly authorized issue of securities of the
Company designated as its "4.25% Convertible Subordinated Notes due July 1,
2008" (herein called the "Securities"), limited in aggregate principal amount to
U.S. $[__________], issued and to be issued under an Indenture, dated as of June
13, 2003 (herein called the "Indenture"), between the Company and Wells Fargo
Bank, National Association, as Trustee (herein called the "Trustee," which term
includes any successor trustee under the Indenture), to which Indenture and all
indentures supplemental thereto reference is hereby made for a statement of the
respective rights, limitations of rights, duties and immunities thereunder of
the Company, the Trustee, the holders of Senior Debt and the Holders of the
Securities and of the terms upon which the Securities are, and are to be,
authenticated and delivered. As provided in the Indenture and subject to certain
limitations therein set forth, Securities are exchangeable for a like aggregate
principal amount of Securities of any authorized denominations as requested by
the Holder surrendering the same upon surrender of the Security or Securities to
be exchanged, at the Corporate Trust Office of the Trustee. The Trustee upon
such surrender by the Holder will issue the new Securities in the requested
denominations.

         No sinking fund is provided for the Securities.

         The Company may not redeem the Securities prior to July 5, 2005. The
Securities are subject to redemption at the option of the Company at any time on
or after July 5, 2005, in whole or in part, at a Redemption Price equal to 100%
of the principal amount (provided, however, that if the Redemption Date is
before July 1, 2007, the Company may redeem the Securities only if the Closing
Price Per Share of the Company's Common Stock exceeds 140% of the Conversion
Price for at least 20 Trading Days in any consecutive 30 day trading period upon
not less than 30 nor more than 60 days' notice to the Holders prior to the
Redemption Date) at a Redemption Price equal to 100% of the principal amount,
together with accrued interest to, but excluding, the Redemption Date; provided,
however, that interest installments on Securities whose Stated Maturity is on or
prior to such Redemption Date will be payable to the Holders of such Securities,
or one or more Predecessor Securities, of record at the close of business on the
relevant Record Dates referred to on the face hereof, all as provided in the
Indenture.

         In the event of a redemption of the Securities, the Company will not be
required (a) to register the transfer or exchange of Securities for a period of
15 days immediately preceding the date notice is given identifying the serial
numbers of the Securities called for such redemption or (b) to register the
transfer or exchange of any Security, or portion thereof, called for redemption.

         In any case where the due date for the payment of the principal of,
premium, if any, interest, or Liquidated Damages on any Security or the last day
on which a Holder of a Security has a right to convert his Security shall be, at
any Place of Payment or Place of Conversion as the case may be, a day on which
banking institutions at such Place of Payment or Place of Conversion are
authorized or obligated by law or executive order to close, then payment of
principal, premium, if any, interest, or Liquidated Damages, or delivery for
conversion of such Security need not be made on or by such date at such place
but may be made on or by the next succeeding day at such place which is not a
day on which banking institutions are authorized or obligated by law or
executive order to close, with the same force and effect as if made on the

<PAGE>

date for such payment or the date fixed for redemption or repurchase, or by such
last day for conversion, and no interest shall accrue on the amount so payable
for the period after such date.

         Subject to and upon compliance with the provisions of the Indenture,
the Holder of this Security is entitled, at his option, at any time on or before
the close of business on the date of Maturity, or in case this Security or a
portion hereof is called for redemption or the Holder hereof has exercised his
right to require the Company to repurchase this Security or such portion hereof,
then in respect of this Security until the Business Day immediately preceding,
but (unless the Company defaults in making the payment due upon redemption or
repurchase, as the case may be) not after, the close of business on the Business
Day immediately preceding the Redemption Date or the Repurchase Date, as the
case may be, to convert this Security (or any portion of the principal amount
hereof that is an integral multiple of U.S.$1,000, provided that the unconverted
portion of such principal amount is U.S.$1,000 or any integral multiple of
U.S.$1,000 in excess thereof) into fully paid and nonassessable shares of Common
Stock of the Company at an initial Conversion Rate of 108.9918 shares of Common
Stock for each U.S.$1,000 principal amount of Securities (or at the current
adjusted Conversion Rate if an adjustment has been made as provided in the
Indenture) by surrender of this Security, duly endorsed or assigned to the
Company or in blank and, in case such surrender shall be made during the period
from the close of business on any Regular Record Date next preceding any
Interest Payment Date to the opening of business on such succeeding Interest
Payment Date (except if this Security or portion thereof has been called for
redemption or if a Change in Control has occurred and an offer to repurchase the
Securities is pending), also accompanied by payment in New York Clearing House
or other funds acceptable to the Company of an amount equal to the interest
payable on such Interest Payment Date on the principal amount of this Security
then being converted, and also the conversion notice hereon duly executed, to
the Company at the Corporate Trust Office of the Trustee, or at such other
office or agency of the Company, subject to any laws or regulations applicable
thereto and subject to the right of the Company to terminate the appointment of
any Conversion Agent (as defined below) as may be designated by it for such
purpose in the Borough of Manhattan, The City of New York, or at such other
offices or agencies as the Company may designate (each a "Conversion Agent").
The interest that is payable on such Interest Payment Date with respect to any
Security (or portion thereof, if applicable) that is surrendered for conversion
during the Record Date Period shall be paid to the Holder of such Security as of
such Regular Record Date in an amount equal to the interest that would have been
payable on such Security if such Security had been converted as of the close of
business on such Interest Payment Date. Subject to the provisions of the
preceding sentence and, in the case of a conversion after the close of business
on the Regular Record Date next preceding any Interest Payment Date and on or
before the close of business on such Interest Payment Date, to the right of the
Holder of this Security (or any Predecessor Security of record as of such
Regular Record Date) to receive the related installment of interest to the
extent and under the circumstances provided in the Indenture, no cash payment or
adjustment is to be made on conversion for interest accrued hereon from the
Interest Payment Date next preceding the day of conversion, or for dividends on
the Common Stock issued on conversion hereof. The Company shall thereafter
deliver to the Holder the fixed number of shares of Common Stock (together with
any cash adjustment, as provided in the Indenture) into which this Security is
convertible and such delivery will be deemed to satisfy the Company's obligation
to pay the principal amount of this Security. No fractions of shares or scrip
representing fractions of shares will be issued on conversion, but instead of
any fractional interest (calculated to the nearest 1/100th of a share) the

<PAGE>

Company shall pay a cash adjustment as provided in the Indenture. The Conversion
Rate is subject to adjustment as provided in the Indenture. In addition, the
Indenture provides that in case of certain consolidations or mergers to which
the Company is a party (other than a consolidation or merger that does not
result in any reclassification, conversion, exchange or cancellation of the
Common Stock) or the conveyance, transfer, sale or lease of all or substantially
all of the property and assets of the Company, the Indenture shall be amended,
without the consent of any Holders of Securities, so that this Security, if then
Outstanding, will be convertible thereafter, during the period this Security
shall be convertible as specified above, only into the kind and amount of
securities, cash and other property receivable upon such consolidation, merger,
conveyance, transfer, sale or lease by a holder of the number of shares of
Common Stock of the Company into which this Security could have been converted
immediately prior to such consolidation, merger, conveyance, transfer, sale or
lease (assuming such holder of Common Stock is not a Constituent Person or an
Affiliate of a Constituent Person, failed to exercise any rights of election and
received per share the kind and amount received per share by a plurality of
Non-electing Shares). No adjustment in the Conversion Rate will be made until
such adjustment would require an increase or decrease of at least one percent of
such rate, provided that any adjustment that would otherwise be made will be
carried forward and taken into account in the computation of any subsequent
adjustment.

         If this Security is a Registrable Security (as defined in the
Indenture), then the Holder of this Security (including any Person that has a
beneficial interest in this Security) and the Common Stock of the Company
issuable upon conversion hereof is entitled to the benefits of a Registration
Rights Agreement, dated as of June 13, 2003, executed by the Company (the
"Registration Rights Agreement"). Pursuant to the Registration Rights Agreement,
the Company has agreed for the benefit of the Holders from time to time of the
Registrable Securities that it will, at its expense, (a) within 90 days after
the Issue Date file a shelf registration statement (the "Shelf Registration
Statement") with the Commission with respect to resales of the Registrable
Securities, (b) use its reasonable efforts to cause such Shelf Registration
Statement to be declared effective by the Commission within 180 days after the
Issue Date, provided, however, that the Company may, upon written notice to all
the Holders, postpone having the Shelf Registration Statement declared effective
for a reasonable period not to exceed 90 days if the Company possesses material
non-public information, the disclosure of which would have a material adverse
effect on the Company and its subsidiaries taken as a whole, and (c) use its
reasonable efforts to maintain such Shelf Registration Statement effective under
the Securities Act of 1933, as amended, until the second annual anniversary of
the Issue Date or, if earlier, until there are no outstanding Registrable
Securities (the "Effectiveness Period"). The Company will be permitted to
suspend the use of the prospectus which is part of the Shelf Registration
Statement during certain periods of time as provided in the Registration Rights
Agreement.

         If (i) on or prior to 90 days following the Issue Date, a Shelf
Registration Statement has not been filed with the Commission, or (ii) on or
prior to the 180th day following the Issue Date, such Shelf Registration
Statement is not declared effective (each, a "Registration Default"), additional
interest ("Liquidated Damages") will accrue on the Registrable Securities from
and including the day following such Registration Default to but excluding the
day on which such Registration Default has been cured. Liquidated Damages will
be paid semi-annually in arrears, with the first semi-annual payment due on the
first Interest Payment Date, as applicable, in respect of the Registrable
Securities following the date on which such Liquidated Damages begin

<PAGE>

to accrue, and will accrue at a rate per annum equal to one-quarter of one
percent (0.25%) of the principal amount of the Registrable Securities to and
including the 90th day following such Registration Default and at a rate per
annum equal to one-half of one percent (0.50%) thereof from and after the 91st
day following such Registration Default. Pursuant to the Registration Rights
Agreement, in the event that the Shelf Registration Statement ceases to be
effective (or the Holders of Registrable Securities are otherwise prevented or
restricted by the Company from effecting sales pursuant thereto) (an "Effective
Failure") during the Effectiveness Period for more than 45 days, whether or not
consecutive, during any 90-day period or for more than 90 days, whether or not
consecutive, during any 365-day period, then the interest rate borne by the
Registrable Securities shall increase by an additional one-quarter of one
percent (0.25%) per annum from the 46th day of the applicable 90-day period or
shall increase by an additional one-half of one percent (0.50%) per annum from
the 91st day of the applicable 365-day period until the earlier of (A) such time
as the Effective Failure is cured or (B) the Effectiveness Period expires.
Liquidated Damages will accrue (1) with respect to a Restricted Security at the
rates set forth above, as applicable, on the principal amount of the Restricted
Securities and (2) in respect of the Common Sock issued upon conversion of the
Restricted Securities, at the rates set forth above, as applicable, applied to
the Conversion Price at that time. In no event shall the Company be required to
pay Liquidated Damages in excess of the applicable maximum amount of one-half of
one percent (0.5%) set forth above regardless of whether one or multiple
Registration Defaults exist.

         Whenever in this Security there is a reference, in any context, to the
payment of the principal of, premium, if any, or interest on, or in respect of,
any Security, such mention shall be deemed to include mention of the payment of
Liquidated Damages payable as described in the preceding paragraph to the extent
that, in such context, Liquidated Damages are, were or would be payable in
respect of such Security and express mention of the payment of Liquidated
Damages (if applicable) in any provisions of this Security shall not be
construed as excluding Liquidated Damages in those provisions of this Security
where such express mention is not made.

         If this Security is a Registrable Security and the Holder of this
Security (including any Person that has a beneficial interest in this Security)
elects to sell this Security pursuant to the Shelf Registration Statement then,
by its acceptance hereof, such Holder of this Security agrees to be bound by the
terms of the Registration Rights Agreement relating to the Registrable
Securities which are the subject of such election.

         If a Change in Control occurs, the Holder of this Security, at the
Holder's option, shall have the right, in accordance with the provisions of the
Indenture, to require the Company to repurchase this Security (or any portion of
the principal amount hereof that is at least $1,000 or an integral multiple of
$1,000 in excess thereof, provided that the portion of the principal amount of
this Security to be Outstanding after such repurchase is at least equal to
U.S.$1,000) for cash at a Repurchase Price equal to 100% of the principal amount
thereof plus interest accrued to the Repurchase Date. Whenever in this Security
there is a reference, in any context, to the principal of any Security as of any
time, such reference shall be deemed to include reference to the Repurchase
Price payable in respect of such Security to the extent that such Repurchase
Price is, was or would be so payable at such time, and express mention of the
Repurchase Price in any

<PAGE>

provision of this Security shall not be construed as excluding the Repurchase
Price so payable in those provisions of this Security when such express mention
is not made.

         In the event of a deposit or withdrawal of an interest in this
Security, including an exchange, transfer, redemption, repurchase or conversion
of this Security in part only, the Trustee, as custodian of the Depositary,
shall make an adjustment on its records to reflect such deposit or withdrawal in
accordance with the Applicable Procedures.

         The indebtedness evidenced by this Security is, to the extent and in
the manner provided in the Indenture, subordinate and subject in right of
payment to the prior payment in full of all Senior Debt of the Company, and this
Security is issued subject to such provisions of the Indenture with respect
thereto. Each Holder of this Security, by accepting the same, (a) agrees to and
shall be bound by such provisions, (b) authorizes and directs the Trustee on his
behalf to take such action as may be necessary or appropriate to effectuate the
subordination so provided and (c) appoints the Trustee his attorney-in-fact for
any and all such purposes.

         If an Event of Default shall occur and be continuing, the principal of
all the Securities, together with accrued interest to the date of declaration,
may be declared due and payable in the manner and with the effect provided in
the Indenture. Upon payment (i) of the amount of principal so declared due and
payable, together with accrued interest to the date of declaration, and (ii) of
interest on any overdue principal and, to the extent permitted by applicable
law, overdue interest, all of the Company's obligations in respect of the
payment of the principal of and interest on the Securities shall terminate.

         The Indenture permits, with certain exceptions as therein provided, the
amendment thereof and the modification of the rights and obligations of the
Company and the rights of the Holders of the Securities under the Indenture at
any time by the Company and the Trustee with either (a) the written consent of
the Holders of not less than a majority in principal amount of the Securities at
the time Outstanding, or (b) by the adoption of a resolution, at a meeting of
Holders of the Outstanding Securities at which a quorum is present, by the
Holders of at least 66 2/3% in aggregate principal amount of the Outstanding
Securities represented and entitled to vote at such meeting. The Indenture also
contains provisions permitting the Holders of specified percentages in principal
amount of the Securities at the time Outstanding, on behalf of the Holders of
all the Securities, to waive compliance by the Company with certain provisions
of the Indenture and certain past defaults under the Indenture and their
consequences. Any such consent or waiver by the Holder of this Security shall be
conclusive and binding upon such Holder and upon all future Holders of this
Security and of any Security issued in exchange therefore or in lieu hereof
whether or not notation of such consent or waiver is made upon this Security or
such other Security. Certain modifications or amendments to the Indenture
require the consent of the Holder of each Outstanding Security affected.

         As provided in and subject to the provisions of the Indenture, the
Holder of this Security shall not have the right to institute any proceeding
with respect to the Indenture or for the appointment of a receiver or trustee or
for any other remedy thereunder, unless such Holder shall have previously given
the Trustee written notice of a continuing Event of Default, the Holders of not
less than 25% in principal amount of the Outstanding Securities shall have made
written request to the Trustee to institute proceedings in respect of such Event
of Default as Trustee and

<PAGE>

offered the Trustee reasonable indemnity and the Trustee shall not have received
from the Holders of a majority in principal amount of the Securities Outstanding
a direction inconsistent with such request, and shall have failed to institute
any such proceeding, for 60 days after receipt of such notice, request and offer
of indemnity. The foregoing shall not apply to any suit instituted by the Holder
of this Security for the enforcement of any payment of principal hereof,
premiums if any, or interest (including Liquidated Damages) hereon on or after
the respective due dates expressed herein or for the enforcement of the right to
convert this Security as provided in the Indenture.

         No reference herein to the Indenture and no provision of this Security
or of the Indenture shall alter or impair the obligation of the Company, which
is absolute and unconditional, to pay the principal of, premium, if any, and
interest (including Liquidated Damages) on this Security at the times, places
and rate, and in the coin or currency, herein prescribed or to convert this
Security as provided in the Indenture.

         As provided in the Indenture and subject to certain limitations therein
set forth, the transfer of this Security is registrable on the Security Register
upon surrender of this Security for registration of transfer at the Corporate
Trust Office of the Trustee or at such other office or agency of the Company as
may be designated by it for such purpose in the Borough of Manhattan, The City
of New York (which shall initially be an office or agency of the Trustee), or at
such other offices or agencies as the Company may designate, duly endorsed by,
or accompanied by a written instrument of transfer in form satisfactory to the
Company and the Security Registrar duly executed by, the Holder thereof or his
attorney duly authorized in writing, and thereupon one or more new Securities,
of authorized denominations and for the same aggregate principal amount, will be
issued to the designated transferee or transferees by the Registrar. No service
charge shall be made for any such registration of transfer or exchange, but the
Company may require payment of a sum sufficient to recover any tax or other
governmental charge payable in connection therewith.

         Prior to due presentation of this Security for registration of
transfer, the Company, the Trustee and any agent of the Company or the Trustee
may treat the Person in whose name such Security is registered, as the owner
thereof for all purposes, whether or not such Security be overdue, and neither
the Company, the Trustee nor any such agent shall be affected by notice to the
contrary.

         No recourse for the payment of the principal (and premium, if any) or
interest on this Security and no recourse under or upon any obligation, covenant
or agreement of the Company in the Indenture or any indenture supplemental
thereto or in any Security, or because of the creation of any indebtedness
represented thereby, shall be had against any incorporator, stockholder,
employee, agent, officer or director or subsidiary, as such, past, present or
future, of the Company or of any successor corporation, either directly or
through the Company or any successor corporation, whether by virtue of any
constitution, statute or rule of law or by the enforcement of any assessment or
penalty or otherwise, all such liability being, by the acceptance hereof and as
part of consideration for the issue hereof, expressly waived and released.

<PAGE>

         THE INDENTURE AND THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN
ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, UNITED STATES OF AMERICA.

         All terms used in this Security which are defined in the Indenture
shall have the meanings assigned to them in the Indenture.

<PAGE>

                                  ABBREVIATIONS

The following abbreviations, when used in the inscription of the face of this
Security, shall be construed as though they were written out in full according
to applicable laws or regulations:

<TABLE>
<S>                <C>                                         <C>                           <C>
TEN COM            as tenant in common                         UNIF GIFT MIN ACT             ____ Custodian ____
TEN ENT            as tenants by the entireties (Cust)                                           (Cust)         (Minor)
JT TEN             as joint tenants with right of                                            under Uniform Gifts to
                   survivorship and not as tenants in common                                 Minors Act _______
                                                                                                         (State)
</TABLE>

Additional abbreviations may also be used though not in the above list.

<PAGE>

                    ELECTION OF HOLDER TO REQUIRE REPURCHASE

         (1)      Pursuant to Section 14.1 of the Indenture, the undersigned
hereby elects to have this Security repurchased by the Company.

         (2)      The undersigned hereby directs the Trustee or the Company to
pay it or ______________ an amount in cash or, at the Company's election, Common
Stock valued as set forth in the Indenture, equal to 100% of the principal
amount to be repurchased (as set forth below), plus interest accrued to, but
excluding, the Repurchase Date, as provided in the Indenture.

Dated: ________________________

_______________________________

Signature(s)

Signature(s) must be guaranteed by an Eligible
Guarantor Institution with membership in an
approved signature guarantee program pursuant
to Rule 17Ad-15 under the Securities Exchange
Act of 1934.

_______________________________

Signature Guaranteed

Principal amount to be repurchased (at least
U.S.$1,000 or an integral multiple of $1,000
in excess thereof): ___________________

Remaining principal amount following such
repurchase (not less than U.S.$1,000):
________________

NOTICE: The signature to the foregoing Election must correspond to the Name as
written upon the face of this Security in every particular, without alteration
or any change whatsoever.