<PAGE>

                                                                     Exhibit 4.3


                                                                  EXECUTION COPY


--------------------------------------------------------------------------------

                                MEDAREX, INC.,

                                  AS ISSUER,

                                      TO

                           WILMINGTON TRUST COMPANY,

                        a national banking association,

                                  AS TRUSTEE

                              ___________________

                                   INDENTURE

                           DATED AS OF JUNE 26, 2001

                              ___________________


                 Up to $201,250,000 Aggregate Principal Amount

                 4.50% CONVERTIBLE SUBORDINATED NOTES DUE 2006

--------------------------------------------------------------------------------
<PAGE>

                               TABLE OF CONTENTS

<TABLE>
<CAPTION>
                                                                                                                 Page
                                                                                                                 ----
<S>                                                                                                              <C>
RECITALS OF THE COMPANY.....................................................................................        1

ARTICLE I           DEFINITIONS AND OTHER PROVISIONS OF GENERAL APPLICATION.................................        1
     SECTION 1.1             Definitions....................................................................        1
     SECTION 1.2             Compliance Certificates and Opinions...........................................       10
     SECTION 1.3             Form of Documents Delivered to the Trustee.....................................       11
     SECTION 1.4             Acts of Holders of Securities..................................................       12
     SECTION 1.5             Notices, Etc., to Trustee and Company..........................................       14
     SECTION 1.6             Notice to Holders of Securities; Waiver........................................       14
     SECTION 1.7             Effect of Headings and Table of Contents.......................................       15
     SECTION 1.8             Successors and Assigns.........................................................       15
     SECTION 1.9             Separability Clause............................................................       15
     SECTION 1.10            Benefits of Indenture..........................................................       15
     SECTION 1.11            Governing Law..................................................................       15
     SECTION 1.12            Legal Holidays.................................................................       16
     SECTION 1.13            Conflict with Trust Indenture Act..............................................       16

ARTICLE II          SECURITY FORMS..........................................................................       16
     SECTION 2.1             Form Generally.................................................................       16
     SECTION 2.2             Form of Security...............................................................       17
     SECTION 2.3             Form of Certificate of Authentication..........................................       27
     SECTION 2.4             Form of Conversion Notice......................................................       27
     SECTION 2.5             Form of Election of Holder to Require Repurchase...............................       29

ARTICLE III         THE SECURITIES..........................................................................       30
     SECTION 3.1             Title and Terms................................................................       30
     SECTION 3.2             Denominations..................................................................       31
     SECTION 3.3             Execution, Authentication, Delivery and Dating.................................       31
     SECTION 3.4             Global Securities; Temporary Securities........................................       32
     SECTION 3.5             Registration, Registration of Transfer and Exchange............................       34
     SECTION 3.6             Mutilated, Destroyed, Lost or Stolen Securities................................       35
     SECTION 3.7             Payment of Interest; Interest Rights Preserved.................................       36
     SECTION 3.8             Persons Deemed Owners..........................................................       37
     SECTION 3.9             Cancellation...................................................................       37
     SECTION 3.10            Computation of Interest........................................................       37
     SECTION 3.11            CUSIP Numbers..................................................................       38
</TABLE>

                                      -i-
<PAGE>

<TABLE>
<CAPTION>
                                                                                                                 Page
                                                                                                                 ----
<S>                                                                                                              <C>
ARTICLE IV          SATISFACTION AND DISCHARGE..............................................................       38
     SECTION 4.1             Satisfaction and Discharge of Indenture........................................       38
     SECTION 4.2             Application of Trust Money.....................................................       39

ARTICLE V           REMEDIES................................................................................       40
     SECTION 5.1             Events of Default..............................................................       40
     SECTION 5.2             Acceleration of Maturity; Rescission and Annulment.............................       41
     SECTION 5.3             Collection of Indebtedness and Suits for Enforcement by Trustee................       42
     SECTION 5.4             Trustee May File Proofs of Claim...............................................       43
     SECTION 5.5             Trustee May Enforce Claims Without Possession of Securities....................       44
     SECTION 5.6             Application of Money Collected.................................................       44
     SECTION 5.7             Limitation on Suits............................................................       45
     SECTION 5.8             Unconditional Right of Holders to Receive Principal, Premium and Interest
                             and to Convert.................................................................       45
     SECTION 5.9             Restoration of Rights and Remedies.............................................       46
     SECTION 5.10            Rights and Remedies Cumulative.................................................       46
     SECTION 5.11            Delay or Omission Not Waiver...................................................       46
     SECTION 5.12            Control by Holders of Securities...............................................       46
     SECTION 5.13            Waiver of Past Defaults........................................................       47
     SECTION 5.14            Undertaking for Costs..........................................................       47

ARTICLE VI          THE TRUSTEE.............................................................................       48
     SECTION 6.1             Certain Duties and Responsibilities............................................       48
     SECTION 6.2             Notice of Defaults.............................................................       49
     SECTION 6.3             Certain Rights of Trustee......................................................       49
     SECTION 6.4             Not Responsible for Recitals or Issuance of Securities.........................       51
     SECTION 6.5             May Hold Securities, Act as Trustee Under Other Indentures.....................       51
     SECTION 6.6             Money Held in Trust............................................................       51
     SECTION 6.7             Compensation and Reimbursement.................................................       51
     SECTION 6.8             Corporate Trustee Required; Eligibility........................................       52
     SECTION 6.9             Resignation and Removal; Appointment of Successor..............................       53
     SECTION 6.10            Acceptance of Appointment by Successor.........................................       54
     SECTION 6.11            Merger, Conversion, Consolidation or Succession to Business....................       55
     SECTION 6.12            Authenticating Agents..........................................................       55
     SECTION 6.13            Disqualification; Conflicting Interests........................................       56
     SECTION 6.14            Preferential Collection of Claims Against Company..............................       56
</TABLE>

                                     -ii-
<PAGE>

<TABLE>
<CAPTION>
                                                                                                                 Page
                                                                                                                 ----
<S>                                                                                                              <C>
ARTICLE VII         CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE....................................       57
     SECTION 7.1             Company May Consolidate, Etc., Only on Certain Terms...........................       57
     SECTION 7.2             Successor Substituted..........................................................       58

ARTICLE VIII        SUPPLEMENTAL INDENTURES.................................................................       58
     SECTION 8.1             Supplemental Indentures Without Consent of Holders of Securities...............       58
     SECTION 8.2             Supplemental Indentures with Consent of Holders of Securities..................       59
     SECTION 8.3             Execution of Supplemental Indentures...........................................       60
     SECTION 8.4             Effect of Supplemental Indentures..............................................       60
     SECTION 8.5             Reference in Securities to Supplemental Indentures.............................       61
     SECTION 8.6             Notice of Supplemental Indentures..............................................       61

ARTICLE IX          COVENANTS...............................................................................       61
     SECTION 9.1             Payment of Principal, Premium and Interest.....................................       61
     SECTION 9.2             Maintenance of Offices or Agencies.............................................       61
     SECTION 9.3             Money for Security Payments To Be Held in Trust................................       62
     SECTION 9.4             Existence......................................................................       63
     SECTION 9.5             Maintenance of Properties......................................................       64
     SECTION 9.6             Payment of Taxes and Other Claims..............................................       64
     SECTION 9.7             Statement by Officers as to Default............................................       64
     SECTION 9.8             Waiver of Certain Covenants....................................................       65

ARTICLE X           REDEMPTION OF SECURITIES................................................................       65
     SECTION  10.1           Right of Redemption............................................................       65
     SECTION  10.2           Applicability of Article.......................................................       65
     SECTION  10.3           Election to Redeem; Notice to Trustee..........................................       65
     SECTION  10.4           Selection by Trustee of Securities To Be Redeemed..............................       66
     SECTION  10.5           Notice of Redemption...........................................................       66
     SECTION  10.6           Deposit of Redemption Price or Make-Whole Payment..............................       68
     SECTION  10.7           Securities Payable on Redemption Date..........................................       68
     SECTION  10.8           Securities Redeemed in Part....................................................       69
     SECTION  10.9           Conversion Arrangement on Call for Redemption..................................       70
     SECTION  10.10          Conditions to the Company's Election to Pay the Make-Whole Payment in
                             Common Stock...................................................................       71
</TABLE>

                                     -iii-
<PAGE>

<TABLE>
<CAPTION>
                                                                                                                 Page
                                                                                                                 ----
<S>                                                                                                              <C>
ARTICLE XI          CONVERSION OF SECURITIES................................................................       72
     SECTION 11.1            Conversion Privilege and Conversion Rate.......................................       72
     SECTION 11.2            Exercise of Conversion Privilege...............................................       72
     SECTION 11.3            Fractions of Shares............................................................       73
     SECTION 11.4            Adjustment of Conversion Rate..................................................       74
     SECTION 11.5            Notice of Adjustments of Conversion Rate.......................................       79
     SECTION 11.6            Notice of Certain Corporate Action.............................................       79
     SECTION 11.7            Company to Reserve Common Stock................................................       81
     SECTION 11.8            Taxes on Conversions...........................................................       81
     SECTION 11.9            Covenant as to Common Stock....................................................       81
     SECTION 11.10           Cancellation of Converted Securities...........................................       81
     SECTION 11.11           Provision in Case of Consolidation, Merger or Sale of Assets...................       81
     SECTION 11.12           Responsibility of Trustee for Conversion Provisions............................       82

ARTICLE XII         SUBORDINATION OF SECURITIES.............................................................       83
     SECTION 12.1            Securities Subordinate to Senior Debt..........................................       83
     SECTION 12.2            No Payments in Certain Circumstances; Payment Over of Proceeds Upon
                             Dissolution, Etc...............................................................       83
     SECTION 12.3            Trustee to Effectuate Subordination............................................       86
     SECTION 12.4            No Waiver of Subordination Provisions..........................................       86
     SECTION 12.5            Notice to Trustee..............................................................       86
     SECTION 12.6            Reliance on Judicial Order or Certificate of Liquidating Agent.................       87
     SECTION 12.7            Trustee Not Fiduciary for Holders of Senior Debt...............................       87
     SECTION 12.8            Reliance by Holders of Senior Debt on Subordination Provisions.................       88
     SECTION 12.9            Rights of Trustee as Holder of Senior Debt; Preservation of Trustee's Rights...       88
     SECTION 12.10           Article Applicable to Paying Agents............................................       88
     SECTION 12.11           Certain Conversions and Repurchases Deemed Payment.............................       89

ARTICLE XIII        REPURCHASE OF SECURITIES AT THE OPTION OF THE HOLDER UPON A CHANGE IN CONTROL...........       89
     SECTION 13.1            Right to Require Repurchase....................................................       89
     SECTION 13.2            Conditions to the Company's Election to Pay the Repurchase Price in Common
                             Stock..........................................................................       90
     SECTION 13.3            Notices; Method of Exercising Repurchase Right, Etc............................       91
     SECTION 13.4            Certain Definitions............................................................       94
</TABLE>

                                     -iv-
<PAGE>

<TABLE>
<CAPTION>
                                                                                                                 Page
                                                                                                                 ----
<S>                                                                                                              <C>
ARTICLE XIV         HOLDERS LISTS AND REPORTS BY TRUSTEE AND COMPANY; NON-RECOURSE..........................       96
     SECTION 14.1            Company to Furnish Trustee Names and Addresses of Holders......................       96
     SECTION 14.2            Preservation of Information....................................................       96
     SECTION 14.3            No Recourse Against Others.....................................................       97
     SECTION 14.4            Reports by Trustee.............................................................       97
     SECTION 14.5            Reports by Company.............................................................       97

ARTICLE XV          IMMUNITY................................................................................       98
     SECTION 15.1            Personal Immunity of Incorporators, Shareholders, Directors and Officers.......       98
     SIGNATURES
</TABLE>

                                      -v-
<PAGE>

     SUBORDINATED DEBT INDENTURE, dated as of June 26, 2001, between Medarex,
Inc., a corporation duly organized and existing under the laws of the State of
New Jersey, having its principal office at 707 State Road #206, Princeton, NJ
08540 (herein called the "Company"), and Wilmington Trust Company, a national
banking association, as Trustee hereunder (herein called the "Trustee").

                            RECITALS OF THE COMPANY

     The Company has duly authorized the creation of an issue of its 4.50%
Convertible Subordinated Notes due 2006 (herein called the "Securities") of
substantially the tenor and amount hereinafter set forth, and to provide
therefor the Company has duly authorized the execution and delivery of this
Indenture.

     All things necessary to make the Securities, when the Securities are
executed by the Company and authenticated and delivered hereunder, the valid
obligations of the Company, and to make this Indenture a valid agreement of the
Company, in accordance with their and its terms, have been done. Further, all
things necessary to duly authorize the issuance of the Common Stock of the
Company issuable upon the conversion of the Securities, and to duly reserve for
issuance the number of shares of Common Stock issuable upon such conversion,
have been done.

                  NOW, THEREFORE, THIS INDENTURE WITNESSETH:

     For and in consideration of the premises and the purchase of the Securities
by the Holders thereof, it is mutually covenanted and agreed, for the equal and
proportionate benefit of all Holders of the Securities, as follows:


                                   ARTICLE I

                       DEFINITIONS AND OTHER PROVISIONS
                            OF GENERAL APPLICATION

SECTION 1.1     Definitions.
                -----------

     For all purposes of this Indenture, except as otherwise expressly provided
or unless the context otherwise requires:

     (1)    the terms defined in this Article have the meanings assigned to them
in this Article and include the plural as well as the singular;

     (2)    all accounting terms not otherwise defined herein have the meanings
assigned to them in accordance with generally accepted accounting principles in
the United States, and,
<PAGE>

except as otherwise herein expressly provided, the term "generally accepted
accounting principles" with respect to any computation required or permitted
hereunder shall mean such accounting principles as are generally accepted at the
date of such computation; and

     (3)     the words "herein," "hereof" and "hereunder" and other words of
similar import refer to this Indenture as a whole and not to any particular
Article, Section or other subdivision.

     "Act," when used with respect to any Holder of a Security, has the meaning
specified in Section 1.4.
             -----------

     "Affiliate" of any specified Person means any other Person directly or
indirectly controlling or controlled by or under direct or indirect common
control with such specified Person. For the purposes of this definition,
"control," when used with respect to any specified Person, means the power to
direct the management and policies of such Person, directly or indirectly,
whether through the ownership of voting securities, by contract or otherwise;
and the terms "controlling" and "controlled" have meanings correlative to the
foregoing.

     "Agent Member" means any member of, or participant in, the Depositary.

     "Applicable Procedures" means, with respect to any transfer or transaction
involving a Global Security or beneficial interest therein, the rules and
procedures of the Depositary for such Security, to the extent applicable to such
transaction and as in effect from time to time.

     "Authenticating Agent" means any Person authorized pursuant to Section 6.12
                                                                    ------------
to act on behalf of the Trustee to authenticate Securities.

     "Authorized Newspaper" means a newspaper in the English language,
customarily published on each Monday, Tuesday, Wednesday, Thursday and Friday,
whether or not published on Saturdays, Sundays or holidays, and of general
circulation in a Place of Payment.

     "Board of Directors" means either the board of directors of the Company or
any duly authorized committee of that board.

     "Board Resolution" means a resolution duly adopted by the Board of
Directors, a copy of which, certified by the Secretary or an Assistant Secretary
of the Company to have been duly adopted by the Board of Directors and to be in
full force and effect on the date of such certification, shall have been
delivered to the Trustee.

     "Business Day," when used with respect to any Place of Payment, Place of
Conversion, New York, New York or any other place, as the case may be, means
each Monday, Tuesday, Wednesday, Thursday and Friday which is not a day on which
banking institutions in such Place of Payment, Place of Conversion or other
place, as the case may be, are authorized or obligated

                                      -2-
<PAGE>

by law or executive order to close; provided, however, that a day on which
                                    --------  -------
banking institutions in New York, New York are authorized or obligated by law or
executive order to close shall not be a Business Day for purposes of Section
                                                                     -------
10.6.
----

     "Change in Control" has the meaning specified in Section 13.4(b).
                                                      ---------------

     "Closing Price Per Share" means, with respect to the Common Stock, for any
day, (i) the last reported sale price regular way on The Nasdaq National Market,
or if no sale occurred on such date, the average of the reported closing bid and
asked prices regular way, or, (ii) if the Common Stock is not quoted on The
Nasdaq National Market, the last reported sale price regular way per share or,
in case no such reported sale takes place on such day, the average of the
reported closing bid and asked prices regular way, in either case, on the
principal national securities exchange on which the Common Stock is listed or
admitted to trading, or (iii) if the Common Stock is not quoted on the Nasdaq
National Market or listed or admitted to trading on any national securities
exchange, the average of the closing bid prices in the over-the-counter market
as furnished by any New York Stock Exchange member firm selected from time to
time by the Company for that purpose.

     "Code" has the meaning specified in Section 2.1.
                                         -----------

     "Commission" means the United States Securities and Exchange Commission, as
from time to time constituted, created under the Exchange Act, or, if at any
time after the execution of this instrument such Commission is not existing and
performing the duties now assigned to it under the Trust Indenture Act, then the
body performing such duties at such time.

     "Common Stock" means the common stock, par value $0.01 per share, of the
Company authorized at the date of this instrument as originally executed or as
such stock may be constituted from time to time. Subject to the provisions of

Section 11.11, shares issuable on conversion or repurchase of Securities shall
-------------
include only shares of Common Stock or shares of any class or classes of common
stock resulting from any reclassification or reclassifications thereof;

provided, however, that if at any time there shall be more than one such
--------  -------
resulting class, the shares so issuable on conversion of Securities shall
include shares of all such classes, and the shares of each such class then so
issuable shall be substantially in the proportion which the total number of
shares of each such class resulting from all such reclassifications bears to the
total number of shares of all such classes resulting from all such
reclassifications.

     "Company" means the Person named as the "Company" in the first paragraph of
this instrument until a successor Person shall have become such pursuant to the
applicable provisions of this Indenture, and thereafter "Company" shall mean
such successor Person.

     "Company Notice" has the meaning specified in Section 13.3.
                                                   ------------

                                      -3-
<PAGE>

     "Company Request" or "Company Order" means a written request or order
signed in the name of the Company by its Chairman of the Board, its Vice
Chairman of the Board, its Chief Executive Officer, its President, its Chief
Financial Officer or a Vice President, and by its Treasurer, an Assistant
Treasurer, its Secretary or an Assistant Secretary, and delivered to the
Trustee.

     "Constituent Person" has the meaning specified in Section 11.11.
                                                       -------------

     "Conversion Agent" means any Person authorized by the Company to convert
Securities in accordance with Article Eleven.  The Company has initially
                              --------------
appointed the Trustee as its Conversion Agent.

     "Conversion Price" has the meaning specified in Section 11.4(10).
                                                     ----------------

     "Conversion Rate" has the meaning specified in Section 11.1.
                                                    ------------

     "Corporate Trust Office" means the office of the Trustee at which at any
particular time its corporate trust business shall be principally administered
(which at the date of this Indenture is located at Rodney Square North, 1100
North Market Street, Wilmington, Delaware 19890).

     "Corporation" means a corporation, company, association, joint-stock
company or business trust.

     "Defaulted Interest" has the meaning specified in Section 3.7.
                                                       -----------

     "Depositary" means, with respect to any Securities, a clearing agency that
is registered as such under the Exchange Act and is designated by the Company to
act as Depositary for such Securities (or any successor securities clearing
agency so registered) as contemplated by Section 3.4.
                                         -----------

     "Designated Senior Debt" means any Senior Debt in which the instrument
creating or evidencing the same or the assumption or guarantee thereof (or
related agreements or documents to which the Company is a party) expressly
provides that such indebtedness shall be "Designated Senior Debt" for purposes
of this Indenture (provided that such instrument, agreement or other document
may place limitations and conditions on the right of such Senior Debt to
exercise the rights of Designated Senior Debt).

     "Dollar" or "U.S.$" means a dollar or other equivalent unit in such coin or
currency of the United States as at the time shall be legal tender for the
payment of public and private debts.

     "DTC" means The Depository Trust Company, a New York corporation.

                                      -4-
<PAGE>

     "Event of Default" has the meaning specified in Section 5.1.
                                                     -----------

     "Exchange Act" means the United States Securities Exchange Act of 1934 (or
any successor statute), as amended from time to time.

     "Global Security" means a Security that is registered in the Security
Register in the name of a Depositary or a nominee thereof.

     "Holder" means the Person in whose name the Security is registered in the
Security Register.

     "Indenture" means this instrument as originally executed or as it may from
time to time be supplemented or amended by one or more indentures supplemental
hereto entered into pursuant to the applicable provisions hereof, including, for
all purposes of this instrument and any such supplemental indenture, the
provisions of the Trust Indenture Act that are deemed to be a part of and govern
this instrument and any such supplemental indenture, respectively.

     "Interest Payment Date" means the Stated Maturity for any installment of
interest on the Securities thereof.

     "Make-Whole Payment" has the meaning specified in Section 2.2.
                                                       -----------

     "Maturity," when used with respect to any Security, means the date on which
the principal of such Security becomes due and payable as therein or herein
provided, whether at the Stated Maturity or by declaration of acceleration, call
for redemption, exercise of the repurchase right set forth in Article Thirteen
                                                              ----------------
or otherwise.

     "Non-electing Share" has the meaning specified in Section 11.11.
                                                       -------------

     "Notice Date" has the meaning specified in Section 2.2.
                                                -----------

     "Notice of Default" has the meaning specified in Section 5.1.
                                                      -----------

     "Officers' Certificate" means a certificate signed by the Chairman of the
Board, a Vice Chairman of the Board, the Chief Executive Officer, the President
or a Vice President and by the principal financial officer, the Treasurer, an
Assistant Treasurer, the Secretary or an Assistant Secretary of the Company, and
delivered to the Trustee.

     "Opinion of Counsel" means a written opinion of counsel, who may be counsel
for the Company and who shall be acceptable to the Trustee.

     "Optional Redemption" has the meaning specified in Section 2.2.
                                                        -----------

                                      -5-
<PAGE>

     "Outstanding," when used with respect to Securities, means, as of the date
of determination, all Securities theretofore authenticated and delivered under
this Indenture, except:
                ------

          (i)   Securities theretofore cancelled by the Trustee or delivered to
     the Trustee for cancellation;

          (ii)  Securities for the payment or redemption of which money in the
     necessary amount has been theretofore deposited with the Trustee or any
     Paying Agent (other than the Company) in trust or set aside and segregated
     in trust by the Company (if the Company shall act as its own Paying Agent)
     for the Holders of such Securities, provided that if such Securities are to
                                         --------
     be redeemed, notice of such redemption has been duly given pursuant to this
     Indenture or irrevocable instructions have been given to the Trustee to
     give such notice; and

          (iii) Securities which have been paid pursuant to Section 3.6 or
                                                            ------------
     in exchange for or in lieu of which other Securities have been
     authenticated and delivered pursuant to this Indenture, other than any such
     Securities in respect of which there shall have been presented to the
     Trustee proof satisfactory to it that such Securities are held by a bona
     fide purchaser in whose hands such Securities are valid obligations of the
     Company;

provided, however, that in determining whether the Holders of the requisite
--------  -------
aggregate principal amount of Outstanding Securities are present at a meeting of
Holders of Securities for quorum purposes or have given any request, demand,
authorization, direction, notice, consent or waiver hereunder, Securities owned
by the Company or any other obligor upon the Securities or any Affiliate of the
Company or such other obligor shall be disregarded and deemed not to be
Outstanding, except that, in determining whether the Trustee shall be protected
in relying upon any such determination as to the presence of a quorum or upon
any such request, demand, authorization, direction, notice, consent or waiver,
only Securities which a Responsible Officer of the Trustee actually knows to be
so owned shall be so disregarded. Securities so owned which have been pledged in
good faith may be regarded as Outstanding if the pledgee establishes to the
satisfaction of the Trustee the pledgee's right so to act with respect to such
Securities and that the pledgee is not the Company or any other obligor upon the
Securities or any Affiliate of the Company or such other obligor.

     "Paying Agent" means any Person authorized by the Company to pay the
principal of, and premium, if any (including the Make-Whole Payment, if
applicable), or interest on any Securities on behalf of the Company and, except
as otherwise specifically set forth herein, such term shall include the Company
if it shall act as its own Paying Agent. The Company has initially appointed the
Trustee as its Paying Agent.

                                      -6-
<PAGE>

     "Person" means any individual, corporation, limited liability company,
partnership, joint venture, trust, estate, unincorporated organization or
government or any agency or political subdivision thereof.

     "Place of Conversion" has the meaning specified in Section 3.1.
                                                        -----------

     "Place of Payment" has the meaning specified in Section 3.1.
                                                     -----------

     "Predecessor Security" of any particular Security means every previous
Security evidencing all or a portion of the same debt as that evidenced by such
particular Security; and, for the purposes of this definition, any Security
authenticated and delivered under Section 3.6 in exchange for or in lieu of a
                                  -----------
mutilated, destroyed, lost or stolen Security shall be deemed to evidence the
same debt as the mutilated, destroyed, lost or stolen Security.

     "Press Release" shall mean any press release issued by the Company and
disseminated through Reuters Business News Services and Bloomberg Business News.

     "Provisional Redemption" has the meaning specified in Section 2.2.
                                                           -----------

     "Record Date" means any Regular Record Date or Special Record Date.

     "Record Date Period" means the period from the close of business of any
Regular Record Date next preceding any Interest Payment Date to the opening of
business on such Interest Payment Date.

     "Redemption Date," when used with respect to any Security to be redeemed,
means the date fixed for such redemption by or pursuant to this Indenture.

     "Redemption Price," when used with respect to any Security to be redeemed,
means the price at which it is to be redeemed pursuant to this Indenture.

     "Registered Securities" has the meaning specified in Section 2.1.
                                                          -----------

     "Regular Record Date" for interest payable in respect of any Security on
any Interest Payment Date means the January 1 or July 1 (whether or not a
Business Day), as the case may be, next preceding such Interest Payment Date.

     "Repurchase Date" has the meaning specified in Section 13.1.
                                                    ------------

     "Repurchase Price" has the meaning specified in Section 13.1.
                                                     ------------

                                      -7-
<PAGE>

     "Responsible Officer," when used with respect to the Trustee, means any
Officer within the Corporate Trust Office of the Trustee, including, without
limitation, any vice president, assistant vice president, assistant treasurer,
corporate trust officer or other employee of the Trustee customarily performing
functions similar to those performed by any of the above designated officers,
and also means, with respect to a particular corporate trust matter, any other
officer to whom such matter is referred because of his knowledge and familiarity
with the particular subject.

     "Securities" has the meaning ascribed to it in the first paragraph hereof
under the caption "Recitals of the Company."

     "Securities Act" means the United States Securities Act of 1933 (or any
successor statute), as amended from time to time.

     "Security Register" and "Security Registrar" have the respective meanings
specified in Section 3.5.
             -----------

     "Senior Debt" means the principal of (and premium, if any) and interest
(including all interest accruing subsequent to the commencement of any
bankruptcy or similar proceeding, whether or not a claim for post-petition
interest is allowable as a claim in any such proceeding) on, and all fees and
other amounts payable in connection with, the following, whether absolute or
contingent, secured or unsecured, due or to become due, outstanding on the date
of this Indenture or thereafter created, incurred or assumed: (a) indebtedness
of the Company evidenced by credit or loan agreements, notes, bonds, debentures,
or other similar instrument, (b) all obligations of the Company for money
borrowed, (c) obligations of the Company as lessee under leases required to be
capitalized on the balance sheet of the lessee under generally accepted
accounting principles, except for obligations of the Company as lessee under any
facility leases, (d) obligations of the Company under interest rate and currency
swaps, caps, floors, collars, hedge agreements, forward contracts, or similar
agreements or arrangements intended to protect the Company against fluctuations
in interest or currency exchange rates or commodity prices, (e) all obligations
with respect to letters of credit, bank guarantees, bankers' acceptances and
similar facilities issued for the account of the Company and all reimbursement
obligations of the Company with respect to the foregoing, (f) all obligations of
the Company issued or assumed as the deferred purchase price of any business,
property, assets (including intangibles) or services (but excluding trade
accounts payable that constitute liabilities arising in the ordinary course of
business), (g) all obligations of the type referred to in clauses (a) through
(f) above of another Person and all dividends of another Person, the payment of
which, in either case, the Company has assumed or guaranteed, or for which the
Company is responsible or liable, directly or indirectly, jointly or severally,
as obligor, guarantor or otherwise, or which is secured by a lien on property of
the Company, and (h) renewals, extensions, modifications, replacements,
restatements and refundings of, or any indebtedness or obligation issued in
exchange for, any such indebtedness or obligation described in clauses (a)
through (g) of this paragraph; provided,
                               --------

                                      -8-
<PAGE>

however, that Senior Debt shall not include the Securities or any such
-------
indebtedness or obligation if the terms of such indebtedness or obligation (or
the terms of the instrument under which, or pursuant to which it is issued)
expressly provides that such indebtedness or obligation is not superior in right
of payment to the Securities; and provided, further, that Senior Debt shall not
                                  --------  -------
include any indebtedness or obligation owed by the Company to any direct or
indirect Subsidiary.

     "Significant Subsidiary" means, with respect to any Person, a Subsidiary of
such Person that would constitute a "significant subsidiary" as such term is
defined under Rule 1-02 of Regulation S-X of the Commission.

     "Special Record Date" for the payment of any Defaulted Interest means a
date fixed by the Company pursuant to Section 3.7.
                                      -----------

     "Stated Maturity," when used with respect to any Security or any
installment of interest thereon, means the date specified in such Security as
the fixed date on which the principal of such Security or such installment of
interest is due and payable.

     "Subsidiary" means a corporation more than 50% of the outstanding voting
stock of which is owned, directly or indirectly, by the Company or by one or
more other Subsidiaries, or by the Company and one or more other Subsidiaries.
For the purposes of this definition, "voting stock" means stock or other similar
interests in the corporation which ordinarily has or have voting power for the
election of directors, or persons performing similar functions, whether at all
times or only so long as no senior class of stock or other interests has or have
such voting power by reason of any contingency.

     "Successor Security" of any particular Security means every Security issued
after, and evidencing all or a portion of the same debt as that evidenced by,
such particular Security; and, for the purposes of this definition, any Security
authenticated and delivered under Section 3.6 in exchange for or in lieu of a
                                  -----------
mutilated, destroyed, lost or stolen Security shall be deemed to evidence the
same debt as the mutilated, destroyed, lost or stolen Security.

     "Time of Delivery" means 9:30 a.m. New York City time on June 26, 2001.

     "Trading Days" means (i) if the Common Stock is listed or admitted for
trading on any national securities exchange, days on which such national
securities exchange is open for business; (ii) if the Common Stock is quoted on
The Nasdaq National Market or any other system of automated dissemination of
quotations of securities prices, days on which trades may be effected through
such system; or (iii) if the Common Stock is not listed or admitted for trading
on any national securities exchange or quoted on The Nasdaq National Market or
any other system of automated dissemination of quotation of securities prices,
days on which the Common

                                      -9-
<PAGE>

Stock is traded regular way in the over-the-counter market and for which a
closing bid and a closing asked price for the Common Stock are available.

     "Trigger Event" shall have the meaning set forth in Section 11.4(7).
                                                         ---------------

     "Trust Indenture Act" means the Trust Indenture Act of 1939 as in force at
the date as of which this instrument was executed; provided, however, that in
                                                   --------  -------
the event the Trust Indenture Act of 1939 is amended after such date, "Trust
Indenture Act" means, to the extent required by any such amendment, the Trust
Indenture Act of 1939 as so amended.

     "Trustee" means the Person named as the "Trustee" in the first paragraph of
this instrument until a successor Trustee shall have become such pursuant to the
applicable provisions of this Indenture, and thereafter "Trustee" shall mean
such successor Trustee.

     "United States" means the United States of America (including the States
and the District of Columbia), its territories, its possessions and other areas
subject to its jurisdiction (its "possessions" including Puerto Rico, the U.S.
Virgin Islands, Guam, American Samoa, Wake Island and the Northern Mariana
Islands).

     "Vice President," when used with respect to the Company, means any vice
president, whether or not designated by a number or a word or words added before
or after the title "vice president."

SECTION 1.2      Compliance Certificates and Opinions.
                 ------------------------------------

     Upon any application or request by the Company to the Trustee to take any
action under any provision of this Indenture, the Company shall furnish to the
Trustee an Officers' Certificate stating that all conditions precedent, if any,
provided for in this Indenture relating to the proposed action have been
complied with and, upon the Trustee's request, an Opinion of Counsel stating
that in the opinion of such counsel all such conditions precedent, if any, have
been complied with, except that in the case of any such application or request
as to which the furnishing of such documents is specifically required by any
provision of this Indenture relating to such particular application or request,
no additional certificate or opinion need be furnished.

     Every certificate or opinion with respect to compliance with a condition or
covenant provided for in this Indenture (including certificates provided for in

Section 9.7) shall include:
-----------

     (1)    a statement that each individual signing such certificate or opinion
has read such covenant or condition and the definitions herein relating thereto;

     (2)    a brief statement as to the nature and scope of the examination or
investigation upon which the statements or opinions contained in such
certificate or opinion are based;

                                      -10-
<PAGE>

     (3)    a statement that, in the opinion of such individual, he has made
such examination or investigation as is necessary to enable him to express an
informed opinion as to whether or not such covenant or condition has been
complied with; and


     (4)    a statement as to whether, in the opinion of each such individual,
such condition or covenant has been complied with.

SECTION 1.3     Form of Documents Delivered to the Trustee.
                ------------------------------------------

     In any case where several matters are required to be certified by, or
covered by an opinion of, any specified Person, it is not necessary that all
such matters be certified by, or covered by the opinion of, only one such
Person, or that they be so certified or covered by only one document, but one
such Person may certify or give an opinion with respect to some matters and one
or more other such Persons as to other matters, and any such Person may certify
or give an opinion as to such matters in one or several documents.

     Any certificate or opinion of an officer of the Company may be based,
insofar as it relates to legal matters, upon a certificate or opinion of, or
representations by, counsel, unless such officer knows, or in the exercise of
reasonable care should know, that the certificate or opinion or representations
with respect to the matters upon which such certificate or opinion is based are
erroneous. Any such certificate or opinion of counsel may be based, insofar as
it relates to factual matters, upon a certificate or opinion of, or
representations by, an officer or officers of the Company or any other Person
stating that the information with respect to such factual matters is in the
possession of the Company or such other Person, unless such counsel knows, or in
the exercise of reasonable care should know, that the certificate or opinion or
representations with respect to such matters are erroneous.

     Where any Person is required to make, give or execute two or more
applications, requests, consents, certificates, statements, opinions or other
instruments under this Indenture, they may, but need not, be consolidated and
form one instrument.

SECTION 1.4     Acts of Holders of Securities.
                -----------------------------

     (a)     Any request, demand, authorization, direction, notice, consent,
waiver or other action provided or permitted by this Indenture to be given or
taken by Holders of Securities may be embodied in and evidenced by one or more
instruments of substantially similar tenor signed by such Holders in person or
by an agent or proxy duly appointed in writing by such Holders. Such action
shall become effective when such instrument or instruments is delivered to the
Trustee and, where it is hereby expressly required, to the Company. The Trustee
shall promptly deliver to the Company copies of all such instruments delivered
to the Trustee. Such instrument or instruments (and the action embodied therein
and evidenced thereby) are herein sometimes referred to as the "Act" of the
Holders of Securities signing such instrument or instruments.

                                      -11-
<PAGE>

Proof of execution of any such instrument or of a writing appointing any such
agent or proxy, or of the holding by any Person of a Security, shall be
sufficient for any purpose of this Indenture and (subject to Section 6.1)
                                                             -----------
conclusive in favor of the Trustee and the Company if made in the manner
provided in this Section.

     (b)    The fact and date of the execution by any Person of any such
instrument or writing may be proved by the affidavit of a witness of such
execution or by a certificate of a notary public or other officer authorized by
law to take acknowledgments of deeds, certifying that the individual signing
such instrument or writing acknowledged to him the execution thereof. Where such
execution is by a signer acting in a capacity other than his individual
capacity, such certificate or affidavit shall also constitute sufficient proof
of his authority.

     (c)    The principal amount and serial number of any Security held by any
Person, the date of his holding the same, and the ownership of Securities
generally shall be proved by the Security Register.

     (d)    The fact and date of execution of any such instrument or writing and
the authority of the Person executing the same may also be proved in any other
manner which the Trustee deems sufficient; and the Trustee may in any instance
require further proof with respect to any of the matters referred to in this
Section 1.4.
-----------

     (e)    The Company may set any day as the record date for the purpose of
determining the Holders entitled to give or take any request, demand,
authorization, direction, notice, consent, waiver or other action, or to vote on
any action, authorized or permitted by this Indenture to be given or taken by
Holders. Promptly and in any case not later than ten days after setting a record
date, the Company shall notify the Trustee and the Holders of such record date.
If not set by the Company prior to the first solicitation of a Holder made by
any Person in respect of any such action, or, in the case of any such vote,
prior to such vote, the record date for any such action or vote shall be the
30th day (or, if later, the date of the most recent list of Holders required to
be provided pursuant to Section 14.1) prior to such first solicitation or vote,
                        ------------
as the case may be. With regard to any record date, the Holders on such date (or
their duly appointed agents or proxies), and only such Persons, shall be
entitled to give or take, or vote on, the relevant action, whether or not such
Holders remain Holders after such record date. Notwithstanding the foregoing,
the Company shall not set a record date for, and the provisions of this
paragraph shall not apply with respect to, any notice, declaration or direction
referred to in the next paragraph.

     Upon receipt by the Trustee from any Holder of (i) any notice of default or
breach referred to in Section 5.1(4), if such default or breach has occurred and
                      --------------
is continuing and the Trustee shall not have given such a notice to the Company,
(ii) any declaration of acceleration referred to in Section 5.2, if an Event of
                                                    -----------
Default has occurred and is continuing and the Trustee shall not have given such
a declaration to the Company, or (iii) any direction referred to in Section
                                                                    -------
5.12, if the Trustee shall not have taken the action specified in such
----
direction, then, with

                                      -12-
<PAGE>

respect to clauses (ii) and (iii), a record date shall automatically and without
any action by the Company or the Trustee be set for determining the Holders
entitled to join in such declaration or direction, which record date shall be
the close of business on the tenth day (or, if such day is not a Business Day,
the first Business Day thereafter) following the day on which the Trustee
receives such declaration or direction, and, with respect to clause (i) the
Trustee may set any day as a record date for the purpose of determining the
Holders entitled to join in such notice of default. Promptly after such receipt
by the Trustee of any such declaration or direction referred to in clause (ii)
or (iii), and promptly after setting any record date with respect to clause (i),
and as soon as practicable thereafter, the Trustee shall notify the Company and
the Holders of any such record date so fixed. The Holders on such record date
(or their duly appointed agents or proxies), and only such Persons, shall be
entitled to join in such notice, declaration or direction, whether or not such
Holders remain Holders after such record date; provided that, unless such
                                               --------
notice, declaration or direction shall have become effective by virtue of
Holders of the requisite principal amount of Securities on such record date (or
their duly appointed agents or proxies) having joined therein on or prior to the
180th day after such record date, such notice, declaration or direction shall
automatically and without any action by any Person be cancelled and of no
further effect. Nothing in this paragraph shall be construed to prevent a Holder
(or a duly appointed agent or proxy thereof) from giving, before or after the
expiration of such 180 day period, a notice, declaration or direction contrary
to or different from, or, after the expiration of such period, identical to, the
notice, declaration or direction to which such record date relates, in which
event a new record date in respect thereof shall be set pursuant to this
paragraph. In addition, nothing in this paragraph shall be construed to render
ineffective any notice, declaration or direction of the type referred to in this
paragraph given at any time to the Trustee and the Company by Holders (or their
duly appointed agents or proxies) of the requisite principal amount of
Securities on the date such notice, declaration or direction is so given.

     (f)    Except as provided in Sections 5.12 and 5.13, any request, demand,
                                  -------------     ----
authorization, direction, notice, consent, election, waiver or other Act of the
Holder of any Security shall bind every future Holder of the same Security and
the Holder of every Security issued upon the registration of transfer thereof or
in exchange therefor or in lieu thereof in respect of anything done, omitted or
suffered to be done by the Trustee or the Company in reliance thereon, whether
or not notation of such action is made upon such Security.

SECTION 1.5     Notices, Etc., to Trustee and Company.
                -------------------------------------

     Any request, demand, authorization, direction, notice, consent, election,
waiver or other Act of Holders of Securities or other document provided or
permitted by this Indenture to be made upon, given or furnished to, or filed
with,

     (1)     the Trustee by any Holder of Securities or by the Company shall be
sufficient for every purpose hereunder if made, given, furnished or filed in
writing to or with the Trustee and

                                      -13-
<PAGE>

received at its Corporate Trust Office, Attention: Medarex, Inc. - 4.50%
Convertible Subordinated Notes due 2006, and shall be deemed given when
received.

     (2)    the Company by the Trustee or by any Holder of Securities shall be
sufficient for every purpose hereunder (unless otherwise herein expressly
provided) if in writing, mailed, first-class postage prepaid, or telecopied and
confirmed by mail, first-class postage prepaid, or delivered by hand or
overnight courier, addressed to the Company at 707 State Road #206, Princeton,
New Jersey 08540, or at any other address previously furnished in writing to the
Trustee by the Company, and shall be deemed given when received.

     Any request, demand, authorization, direction, notice, consent, election or
waiver required or permitted under this Indenture shall be in the English
language, except that any published notice may be in an official language of the
country of publication.

SECTION 1.6     Notice to Holders of Securities; Waiver.
                ---------------------------------------

     Except as otherwise expressly provided herein, where this Indenture
provides for notice to Holders of Securities of any event, such notice shall be
sufficiently given to Holders if in writing and mailed, first-class postage
prepaid, to each Holder of a Security affected by such event, at the address of
such Holder as it appears in the Security Register, not earlier than the
earliest date and not later than the latest date prescribed for the giving of
such notice.

     Neither the failure to mail such notice, nor any defect in any notice so
mailed, to any particular Holder of a Security shall affect the sufficiency of
such notice with respect to other Holders of Securities. In case by reason of
the suspension of regular mail service or by reason of any other cause it shall
be impracticable to give such notice by mail, then such notification to Holders
of Securities as shall be made with the approval of the Trustee, which approval
shall not be unreasonably withheld, shall constitute a sufficient notification
to such Holders for every purpose hereunder.

     Such notice shall be deemed to have been given when such notice is mailed.

     Where this Indenture provides for notice in any manner, such notice may be
waived in writing by the Person entitled to receive such notice, either before
or after the event, and such waiver shall be the equivalent of such notice.
Waivers of notice by Holders of Securities shall be filed with the Trustee, but
such filing shall not be a condition precedent to the validity of any action
taken in reliance upon such waiver.

                                      -14-
<PAGE>

SECTION 1.7    Effect of Headings and Table of Contents.
               ----------------------------------------

     The Article and Section headings herein and the Table of Contents are for
convenience only and shall not affect the construction hereof.

SECTION 1.8    Successors and Assigns.
               ----------------------

     All covenants and agreements in this Indenture by the Company shall bind
its successors and assigns, whether so expressed or not.

SECTION 1.9    Separability Clause.
               -------------------

     In case any provision in this Indenture or the Securities shall be invalid,
illegal or unenforceable, the validity, legality and enforceability of the
remaining provisions shall not in any way be affected or impaired thereby.

SECTION 1.10   Benefits of Indenture.
               ---------------------

     Except as provided in the next sentence, nothing in this Indenture or in
the Securities, express or implied, shall give to any Person, other than the
parties hereto and their successors and assigns hereunder and the Holders of
Securities, any benefit or legal or equitable right, remedy or claim under this
Indenture.  The provisions of Article Twelve are intended to be for the benefit
                              --------------
of, and shall be enforceable directly by, the holders of Senior Debt, except as
otherwise provided in Section 12.3.

SECTION 1.11   Governing Law.
               -------------

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

SECTION 1.12   Legal Holidays.
               --------------

     In any case where any Interest Payment Date, Redemption Date, Repurchase
Date or Stated Maturity of any Security or the last day on which a Holder of a
Security has a right to convert his Security shall not be a Business Day, then
(notwithstanding any other provision of this Indenture or of the Securities)
payment of principal of, premium, if any (including the Make-Whole Payment, if
any), or interest on, or the payment of the Repurchase Price (whether the same
is payable in cash or in shares of Common Stock) with respect to, or delivery
for conversion of, such Security need not be made on or by such day, but may be
made on or by the next succeeding Business Day with the same force and effect as
if made on the Interest Payment Date, Redemption Date or Repurchase Date, or at
the Stated Maturity or by such last day for

                                      -15-
<PAGE>

conversion; provided, however, that in the case that payment is made on such
            --------  -------
succeeding Business Day, no interest shall accrue on the amount so payable for
the period from and after such Interest Payment Date, Redemption Date,
Repurchase Date, Stated Maturity or last day for conversion, as the case may be.

SECTION 1.13   Conflict with Trust Indenture Act.
               ---------------------------------

     If any provision hereof limits, qualifies or conflicts with a provision of
the Trust Indenture Act that is required under such Act to be a part of and
govern this Indenture, the latter provision shall control.  If any provision of
this Indenture modifies or excludes any provision of the Trust Indenture Act
that may be so modified or excluded, the latter provision shall be deemed to
apply to this Indenture as so modified or to be excluded, as the case may be.

                                  ARTICLE II

                                SECURITY FORMS

SECTION 2.1    Form Generally.
               --------------

     The Securities shall be in substantially the form set forth in this
Article, with such appropriate insertions, omissions, substitutions and other
variations as are required or permitted by this Indenture, and may have such
letters, numbers or other marks of identification and such legends or
endorsements placed thereon as may be required to comply with the rules of any
securities exchange or the Internal Revenue Code of 1986, as amended, and
regulations thereunder (the "Code"), or as may, consistently herewith, be
determined by the officers executing such Securities, as evidenced by their
execution thereof.  All Securities shall be issued in registered form, as
opposed to bearer form, and shall sometimes be referred to as "Registered
Securities".

     The Trustee's certificates of authentication shall be in substantially the
form set forth in Section 2.3.
                  -----------

     Conversion notices shall be in substantially the form set forth in Section
                                                                        -------
2.4.
---

     Repurchase notices shall be substantially in the form set forth in Section
                                                                        -------
2.5.
---

     The Securities shall be printed, lithographed, typewritten or engraved or
produced by any combination of these methods on steel engraved borders if so
required by any securities exchange upon which the Securities may be listed, or
may be produced in any other manner permitted by the rules of any such
securities exchange, or, if the Securities are not listed on a securities
exchange, in any other manner approved by the Company, all as determined by the
officers executing such Securities, as evidenced by their execution thereof.

                                      -16-
<PAGE>

     Upon their original issuance, Securities shall be issued in the form of one
or more Global Securities without interest coupons and shall be registered in
the name of DTC, as Depositary, or its nominee and deposited with the Trustee,
as custodian for DTC, for credit by DTC to the respective accounts of beneficial
owners of the Securities represented thereby (or such other accounts as they may
direct).  Such Global Security, together with its Successor Securities which are
Global Securities, are collectively herein called the "Restricted Global
Security."

SECTION 2.2    Form of Security.
               ----------------

                                [FORM OF FACE]

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

     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.]

     [THE FOLLOWING LEGEND SHALL APPEAR ON THE FACE OF EACH GLOBAL SECURITY FOR
WHICH THE DEPOSITORY TRUST COMPANY IS TO BE THE DEPOSITARY:

     UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE
DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION ("DTC"), TO ISSUER 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.]

                                      -17-
<PAGE>

                                 MEDAREX, INC.

                 4.50% Convertible Subordinated Notes due 2006

No. _______________                                              U.S.$ _______

CUSIP No. 583916 AA 9

     Medarex, Inc., a corporation duly organized and existing under the laws of
the State of New Jersey (herein called the "Company," which term includes any
successor Person to the Company 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 decreased by
adjustments made on the records of the Trustee hereinafter referred to in
accordance with the Indenture) on July 1, 2006 and to pay interest thereon, from
June 26, 2001, 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, 2002, at the rate of 4.50% per annum, until the principal
hereof is due, and at the rate of 4.50% 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 such Special Record Date, or be paid at any time
in any other lawful manner not inconsistent with the requirements of any
securities exchange on which the Securities may be 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, in such coin or currency 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 wire 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) maintained by the payee with a bank in the
Borough of Manhattan, The City of New York. Payment of interest on this Security

                                      -18-
<PAGE>

may be made by United States Dollar check drawn on a bank in the Borough of
Manhattan, The City of New York 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 Date, by wire transfer to a
United States Dollar account (such a wire 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) maintained by
the payee with a bank in the Borough of Manhattan, The City of New York.

     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.

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

                         MEDAREX, INC.



                         By: __________________________________
                             Name:
                             Title:

                                      -19-
<PAGE>

                               [FORM OF REVERSE]

     This Security is one of a duly authorized issue of securities of the
Company designated as its 4.50% Convertible Subordinated Notes due 2006 (herein
called the "Securities"), limited in aggregate principal amount not to exceed
U.S.$175,000,000 as such amount may be increased, but not by an amount in excess
of $26,250,000, solely as a result of the exercise of the underwriters' over-
allotment option granted by the Company under the underwriting agreement, dated
June 21, 2001, among the Company, Goldman, Sachs & Co., Credit Suisse First
Boston Corporation, J.P. Morgan Securities Inc., Morgan Stanley & Co.
Incorporated, Bear Stearns & Co., Inc. and Dain Rauscher Incorporated (the
"Underwriters") to the several Underwriters, issued and to be issued under an
Indenture, dated as of June 26, 2001  (herein called the "Indenture"), between
the Company and Wilmington Trust Company, a national banking 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 Securities are subject to provisional redemption by the Company
("Provisional Redemption"), in whole or in part, at any time prior to July 1,
2004, upon notice as set forth in Section 10.5 of the Indenture, at a Redemption
Price equal to the principal amount of the Securities to be redeemed plus
accrued and unpaid interest, if any, to the Redemption Date if the Closing Price
of the Common Stock shall have exceeded 150% of the Conversion Price then in
effect for at least 20 Trading Days in any consecutive 30-day Trading Day period
ending on the Trading Day prior to the date mailing of the notice of Provisional
Redemption pursuant to Section 10.5 of the Indenture (the "Notice Date").  Upon
any such Provisional Redemption, the Company shall make an additional payment
(the "Make-Whole Payment") in cash or, at the election of the Company upon
satisfaction of the conditions in Section 10.10 of the Indenture, in Common
Stock, as specified in the notice of redemption, with respect to the Securities
called for redemption to holders on the Notice Date in an amount equal to $135
per $1,000 aggregate principal amount of Security, less the amount of any
interest actually paid or accrued and unpaid on such Security prior to the
Notice Date.  The Make-Whole Payment will not be reduced by the amount of
interest accrued and unpaid prior to the Notice Date in the case of a Security
converted into Common Stock after the Notice Date.  The Company shall make the
Make-Whole Payment on all Securities called for Provisional Redemption,
including any Securities converted into

                                      -20-
<PAGE>

Common Stock pursuant to the terms of the Indenture after the Notice Date and
prior to the Redemption Date. For purposes of this paragraph, the payments made
in Common Stock will be determined by the Company and each share of Common Stock
to be delivered shall be valued at an amount equal to 95% of the average of the
Closing Price Per Share of the Common Stock for the five consecutive Trading
Days immediately preceding and including the third Trading Day prior to the
Redemption Date.

     The Securities are also subject to redemption at the option of the Company
("Optional Redemption") at any time on or after July 1, 2004, in whole or in
part, upon not less than 30 nor more than 60 days' notice to the Holders prior
to the Redemption Date at the following Redemption Prices (expressed as
percentages of the principal amount) for the twelve-month period beginning on
July 1 of the following years:

<TABLE>
<CAPTION>
                         Year           Redemption Price
                        ------          -----------------
                   <S>                  <C>
                   2004.............          101.8%
                   2005.............          100.9%
</TABLE>

and at a Redemption Price equal to 100% of the principal amount on and after
July 1, 2006, together, in each case, with accrued interest to 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.

     Notice to the Holders will be given not less than 30 nor more than 60 days
prior to the Redemption Date as provided in the Indenture.

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

                                      -21-
<PAGE>

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 following the
original issue date of the Securities and on or before the close of business on
July 1, 2006, or in case this Security or a portion hereof is called for
redemption or the Holder hereof has exercised its right to require the Company
to repurchase this Security or such portion hereof, then in respect of this
Security until and including, 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 34.6789 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 Interest Payment Date (except if this Security has been called
for redemption on a Redemption Date or is repurchasable on a Repurchase Date
occurring, in either case, during such period and is surrendered for such
conversion during such period), also accompanied by payment in New York Clearing
House or other funds acceptable to the Company of an amount equal to the
interest otherwise 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"), provided, that if this Security or portion hereof has been
                     --------
called for redemption on a Redemption Date or is repurchasable on a Repurchase
Date occurring, in either case, 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 and is surrendered for
conversion during such period, then the Holder of this Security shall not be
required to pay such interest upon surrender of this Security for conversion.
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

                                      -22-
<PAGE>

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 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 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, 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 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 equal to U.S.$1,000 or any integral multiple
of 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.  At the option of
the Company, the Repurchase Price may be paid in cash or, subject to the
conditions provided in the Indenture, by delivery of shares of Common Stock
having a fair market value equal to the Repurchase Price.  For purposes of this
paragraph, the fair market value of shares of Common Stock shall be determined
by the Company and shall be equal to 95% of the average of the Closing Price Per
Share for the five consecutive Trading Days immediately preceding and including
the third Trading Day prior 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 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; provided, however, that, for the purposes
                                       --------  -------
of the second succeeding

                                      -23-
<PAGE>

paragraph, such reference shall be deemed to include reference to the Repurchase
Price only to the extent the Repurchase Price is payable in cash.

     [The following paragraph shall appear in each Security that is not a Global
Security:

     In the event of redemption, repurchase or conversion of this Security in
part only, a new Security or Securities for the unredeemed, unrepurchased or
unconverted portion hereof will be issued in the name of the Holder hereof.]

     [The following paragraph shall appear in each Global Security:

     In the event of a withdrawal of an interest in this Security resulting from
any 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 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 the written consent of the Holders
of a majority in aggregate principal amount of the Securities at the time
Outstanding.  The Indenture also contains provisions permitting the Holders of
specified percentages in aggregate 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

                                      -24-
<PAGE>

Holder and upon all future Holders of this Security and of any Security issued
in exchange herefor or in lieu hereof, whether or not notation of such consent
or waiver is made upon this Security or such other Security.

     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 aggregate 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 furnished the Trustee reasonable indemnity, and
shall have failed to institute any such proceeding, for 60 days after receipt of
such notice, request and furnishing 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, premium, if any, or interest 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, as between the Company and any Holder, alter or impair
the obligation of the Company, which is absolute and unconditional, to pay the
principal of, premium, if any (including the Make-Whole Payment, if any), and
interest 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 Securities is registrable on the Security Register upon
surrender of a 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, 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 Security 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 a 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.

                                      -25-
<PAGE>

     Interest on the Securities shall be computed on the basis of a 360-day year
of twelve 30-day months.

     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.

SECTION 2.3    Form of Certificate of Authentication.
               -------------------------------------

     The Trustee's certificates of authentication shall be in substantially the
     following form:

     Dated:    [Date of Authentication]

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

                         Wilmington Trust Company, as Trustee

                         By:  _________________________________
                                    Authorized Signatory

SECTION 2.4    Form of Conversion Notice.
               -------------------------

                               CONVERSION NOTICE

     The undersigned Holder of this Security hereby irrevocably exercises the
option to convert this Security, or any portion of the principal amount hereof
(which is an integral multiple of U.S.$1,000) below designated, into shares of
Common Stock in accordance with the terms of the Indenture referred to in this
Security, and directs that such shares, together with a check in payment for any
fractional share and any Securities representing any unconverted principal
amount hereof, be delivered to and be registered in the name of the undersigned
unless a different name has been indicated below. If shares of Common Stock or
Securities are to be registered in the name of a Person other than the
undersigned, the undersigned will pay all transfer taxes payable with respect
thereto. Any amount required to be paid by the undersigned on account of
interest accompanies this Security.


Dated: ___________________________


                                    ___________________________________
                                              Signature

                                      -26-
<PAGE>

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

<TABLE>
<S>                                                <C>
If shares or Securities are to be registered in    If only a portion of the Securities is to
the name of a Person other than the Holder,        be converted, please indicate:
please print such Person's name and address:

________________________________________________   1.  Principal amount to be converted:
                Name
                                                   U.S.$_______
________________________________________________
              Address                              2.  Principal amount and denomination
                                                   of Securities representing unconverted
________________________________________________   principal amount to be issued:
Social Security or other Taxpayer
Identification Number, if any                      Amount:  U.S.$_______

________________________________________________   Denominations:
                                                   U.S.$_______
                                                   (any integral multiple of U.S.$1,000)

                                                   ____________________________________
                                                                  Signature


                                                   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
</TABLE>

SECTION 2.5    Form of Election of Holder to Require Repurchase.
               ------------------------------------------------

                   ELECTION OF HOLDER TO REQUIRE REPURCHASE

     1.   Pursuant to Section 13.1 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

                                      -27-
<PAGE>

set forth in the Indenture, equal to 100% of the principal amount to be
repurchased (as set forth below), plus interest accrued to the Repurchase Date,
as provided in the Indenture.

                              Dated:    ________________________________

                                        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

                                        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


Principal amount to be repurchased
(an amount of U.S. $1,000 or an integral
multiple of U.S.$1,000):


Remaining principal amount following such repurchase:


                                        ___________________________
                                                  Signature

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.

                                      -28-
<PAGE>

                                  ARTICLE III

                                THE SECURITIES

SECTION 3.1    Title and Terms.
               ---------------

     The aggregate principal amount of Securities which may be authenticated and
delivered under this Indenture is limited to U.S.$175,000,000, as such amount
may be increased, but not by an amount in excess of $26,250,000, solely as a
result of the purchase of additional Securities pursuant to the underwriters'
over-allotment option granted by the Company under the underwriting agreement,
dated June 21, 2001 (the "Underwriting Agreement"), among the Company, Goldman,
Sachs & Co., Credit Suisse First Boston Corporation, J.P. Morgan Securities
Inc., Morgan Stanley & Co. Incorporated, Bear Stearns & Co., Inc. and Dain
Rauscher Incorporated (collectively, the "Underwriters"), to the several
Underwriters (referred to in the Underwriting Agreement and this Indenture as
the "Additional Securities") except for Securities authenticated and delivered
in exchange for, or in lieu of, other Securities pursuant to Section 3.4, 3.5,
                                                             -----------  ---
3.6, 8.5, 10.8, 11.2 or 13.3(e).
---  ---  ----  ----    -------

     The Securities shall be known and designated as the "4.50% Convertible
Subordinated Notes due 2006" of the Company.  Their Stated Maturity shall be
July 1, 2006 and they shall bear interest on their principal amount from the
date of the Time of Delivery, payable semi-annually in arrears on January 1 and
July 1 each year, commencing January 1, 2002, at the rate of 4.50% per annum
until the principal thereof is due and at the rate of 4.50% per annum on any
overdue principal and, to the extent permitted by law, on any overdue interest;
provided, however, that payments shall only be made on Business Days as provided
--------  -------
in Section 1.12.
   ------------

     Upon receipt by the Trustee of an Officers' Certificate stating that the
Underwriters have elected to purchase from the Company a specified aggregate
principal amount of Additional Securities not to exceed a total of $26,250,000
all such elections in accordance with this paragraph pursuant to the
Underwriting Agreement, the Trustee shall authenticate and make available for
delivery such specified aggregate principal amount of such Additional Securities
to or upon a Company Request, and such specified aggregate principal amount of
such Additional Securities shall be considered part of the original aggregate
principal amount of the Securities.

     The principal of, premium, if any (including the Make-Whole Payment, if
any), and interest on the Securities shall be payable as provided in the form of
Securities set forth in Section 2.2, and the Repurchase Price, whether payable
                        -----------
in cash or in shares of Common Stock, shall be payable at such places as are
identified in the Company Notice given pursuant to Section 13.3 (any city in
                                                   ------------
which any Paying Agent is located being herein called a "Place of Payment").

                                      -29-
<PAGE>

     The Securities shall be redeemable at the option of the Company, as
provided in Article Ten and shall be issued in the form of Securities set forth
            -----------
in Section 2.2.
   -----------

     The Securities shall be convertible as provided in Article Eleven (any city
                                                        --------------
in which any Conversion Agent is located being herein called a "Place of
Conversion").

     The Securities shall be subordinated in right of payment to Senior Debt of
the Company as provided in Article Twelve.
                           --------------

     The Securities shall be subject to repurchase by the Company at the option
of the Holders as provided in Article Thirteen.
                              ----------------

SECTION 3.2    Denominations.
               -------------

     The Securities shall be issuable only in registered form, without coupons,
in denominations of U.S.$1,000 and integral multiples thereof.

SECTION 3.3    Execution, Authentication, Delivery and Dating.
               ----------------------------------------------

     The Securities shall be executed on behalf of the Company by its Chairman
of the Board, its Vice Chairman of the Board, its Chief Executive Officer, its
President, its Chief Financial Officer or one of its Vice Presidents, under a
facsimile of its corporate seal reproduced thereon attested by its Secretary or
one of its Assistant Secretaries.  Any such signature may be manual or
facsimile.

     Securities bearing the manual or facsimile signature of individuals who
were at any time the proper officers of the Company shall bind the Company,
notwithstanding that such individuals or any of them have ceased to hold such
offices prior to the authentication and delivery of such Securities or did not
hold such offices at the date of such Securities.

     At any time and from time to time after the execution and delivery of this
Indenture, the Company may deliver Securities executed by the Company to the
Trustee or to its order for authentication, together with a Company Order for
the authentication and delivery of such Securities, and the Trustee in
accordance with such Company Order shall authenticate and make available for
delivery such Securities as in this Indenture provided and not otherwise.

     Each Security shall be dated the date of its authentication.

     No Security shall be entitled to any benefit under this Indenture or be
valid or obligatory for any purpose unless there appears on such Security a
certificate of authentication substantially in the form provided for herein
executed by the Trustee by manual signature of an authorized

                                      -30-
<PAGE>

signatory, and such certificate upon any Security shall be conclusive evidence,
and the only evidence, that such Security has been duly authenticated and
delivered hereunder.

SECTION 3.4    Global Securities; Temporary Securities.
               ---------------------------------------

(A)  Global Securities

     (a)  Each Global Security authenticated under this Indenture shall be
registered in the name of the Depositary designated by the Company for such
Global Security or a nominee thereof and delivered to such Depositary or a
nominee thereof or custodian therefor, and each such Global Security shall
constitute a single Security for all purposes of this Indenture.  The Company
hereby appoints DTC as the Depositary.

     (b)  Notwithstanding any other provision in this Indenture, no Global
Security may be exchanged in whole or in part for Securities registered, and no
transfer of a Global Security in whole or in part may be registered, in the name
of any Person other than the Depositary for such Global Security or a nominee
thereof unless (i) such Depositary (A) has notified the Company that it is
unwilling or unable to continue as Depositary for such Global Security or (B)
has ceased to be a clearing agency registered as such under the Exchange Act or
announces an intention permanently to cease business or does in fact do so or
(ii) there shall have occurred and be continuing an Event of Default with
respect to such Global Security.

     (c)  Every Security authenticated and delivered upon registration of
transfer of, or in exchange for or in lieu of, a Global Security or any portion
thereof, whether pursuant to this Article Three or otherwise, shall be
                                  -------------
authenticated and delivered in the form of, and shall be a registered Global
Security, unless such Security is registered in the name of a Person other than
the Depositary for such Global Security or a nominee thereof, in which case such
Security shall be authenticated and delivered in definitive, fully registered
form, without interest coupons.

     (d)  The Depositary or its nominee, as registered owner of a Global
Security, shall be the Holder of such Global Security for all purposes under the
Indenture and the Securities, and owners of beneficial interests in a Global
Security shall hold such interests pursuant to the Applicable Procedures.
Accordingly, any such owner's beneficial interest in a Global Security will be
shown only on, and the transfer of such interest shall be effected only through,
records maintained by the Depositary or its nominee or its Agent Members and
such owners of beneficial interests in a Global Security will not be considered
the owners or holders thereof.

     (e)   If any Global Security is to be cancelled in part as a result of the
redemption, repurchase or conversion of such security in part only, then the
principal amount thereof shall be reduced by an amount equal to the portion
thereof to be so cancelled by means of an appropriate adjustment made on the
records of the Trustee, as Security Registrar, whereupon the Trustee, in
accordance with the Applicable Procedures, shall instruct the Depositary or its
authorized

                                      -31-
<PAGE>

representative to make a corresponding adjustment to its records. The Trustee
shall be entitled to rely upon any order, direction or request of the Depositary
or its authorized representative which is given or made pursuant to this Article
                                                                         -------
Three if such order, direction or request is given or made in accordance with
-----
the Applicable Procedures.

(B)  Temporary Securities
     --------------------

     Pending the preparation of definitive Securities, the Company may execute,
and upon Company Order the Trustee shall authenticate and make available for
delivery, temporary Securities which are printed, lithographed, typewritten,
mimeographed or otherwise produced, in any authorized denomination,
substantially of the tenor of the definitive Securities in lieu of which they
are issued and with such appropriate insertions, omissions, substitutions and
other variations as the officers executing such Securities may determine, as
evidenced by their execution of such Securities.

     If temporary Securities are issued, the Company will cause definitive
Securities to be prepared without unreasonable delay.  After the preparation of
definitive Securities, the temporary Securities shall be exchangeable for
definitive Securities upon surrender of the temporary Securities at any office
or agency of the Company designated pursuant to Section 9.2, without charge to
                                                -----------
the Holder.  Upon surrender for cancellation of any one or more temporary
Securities the Company shall execute and the Trustee shall authenticate and make
available for delivery in exchange therefor a like principal amount of
definitive Securities of authorized denominations.  Until so exchanged the
temporary Securities shall in all respects be entitled to the same benefits
under this Indenture as definitive Securities.

SECTION 3.5    Registration, Registration of Transfer and Exchange.
               ---------------------------------------------------

     The Company shall cause to be kept at the Corporate Trust Office of the
Trustee a register (the register maintained in such office and in any other
office or agency of the Company designated pursuant to Section 9.2 being herein
                                                       -----------
sometimes collectively referred to as the "Security Register") in which, subject
to such reasonable regulations as it may prescribe and provide to the Trustee in
writing, the Company shall provide for the registration of Securities and of
transfers of Securities.  The Trustee is hereby appointed "Security Registrar"
for the purpose of registering Securities and transfers and exchanges of
Securities as herein provided.

     Upon surrender for registration of transfer of any Security at an office or
agency of the Company designated pursuant to Section 9.2 for such purpose, the
                                             -----------
Company shall execute, and the Trustee shall authenticate and deliver, in the
name of the designated transferee or transferees, one or more new Securities of
any authorized denominations and of a like aggregate principal amount and
bearing such restrictive legends as may be required by this Indenture.

                                      -32-
<PAGE>

     At the option of the Holder, and subject to the other provisions of this
Section 3.5, Securities may be exchanged for other Securities of any authorized
-----------
denomination and of a like aggregate principal amount, upon surrender of the
Securities to be exchanged at any such office or agency.  Whenever any
Securities are so surrendered for exchange, and subject to the other provisions
of this Section 3.5, the Company shall execute, and the Trustee shall
        -----------
authenticate and make available for delivery, the Securities which the Holder
making the exchange is entitled to receive.  Every Security presented or
surrendered for registration of transfer or for exchange shall (if so required
by the Company or the Security Registrar) be duly endorsed, or be accompanied by
a written instrument of transfer in form satisfactory to the Security Registrar
duly executed, by the Holder thereof or his attorney duly authorized in writing.

     All Securities issued upon any registration of transfer or exchange of
Securities shall be the valid obligations of the Company, evidencing the same
debt, and subject to the other provisions of this Section 3.5, entitled to the
                                                  -----------
same benefits under this Indenture, as the Securities surrendered upon such
registration of transfer or exchange.

     No service charge shall be made for any registration of transfer or
exchange of Securities except as provided in Section 3.6, but the Company may
                                             -----------
require payment of a sum sufficient to cover any tax or other governmental
charge that may be imposed in connection with any registration of transfer or
exchange of Securities, other than exchanges pursuant to Section 3.4, 10.8, 11.2
                                                         -----------  ----  ----
or 13.3 (other than where the shares of Common Stock are to be issued or
   ----
delivered in a name other than that of the Holder of the Security) not involving
any transfer and other than any stamp and other duties, if any, which may be
imposed in connection with any such transfer or exchange by the United States or
any political subdivision thereof or therein, which shall be paid by the
Company.

     In the event of a redemption of the Securities, the Company will not be
required (a) to register the transfer of or exchange 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 of or exchange any Security, or portion thereof, called for redemption.

SECTION 3.6    Mutilated, Destroyed, Lost or Stolen Securities.
               -----------------------------------------------

     If any mutilated Security is surrendered to the Trustee, the Company shall
execute and the Trustee shall authenticate and make available for delivery in
exchange therefor a new Security of like tenor and principal amount and bearing
a number not contemporaneously outstanding.

     If there be delivered to the Company and to the Trustee:

     (1) evidence to their satisfaction of the destruction, loss or theft of any
Security, and

                                      -33-
<PAGE>

     (2) such security or indemnity as may be satisfactory to the Company and
the Trustee to save each of them and any agent of either of them harmless,

then, in the absence of actual notice to the Company or the Trustee that such
Security has been acquired by a bona fide purchaser, the Company shall execute
and the Trustee shall authenticate and make available for delivery, in lieu of
any such destroyed, lost or stolen Security, a new Security of like tenor and
principal amount and bearing a number not contemporaneously outstanding.

     In case any such mutilated, destroyed, lost or stolen Security has become
or is about to become due and payable, the Company in its discretion, but
subject to any conversion rights, may, instead of issuing a new Security, pay
such Security, upon satisfaction of the conditions set forth in the preceding
paragraph.

     Upon the issuance of any new Security under this Section 3.6, 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 (other than any
stamp and other duties, if any, which may be imposed in connection therewith by
the United States or any political subdivision thereof or therein, which shall
be paid by the Company) and any other expenses (including the fees and expenses
of the Trustee) connected therewith.

     Every new Security issued pursuant to this Section 3.6 in lieu of any
                                                -----------
mutilated, destroyed, lost or stolen Security shall constitute an original
additional contractual obligation of the Company, whether or not the mutilated,
destroyed, lost or stolen Security shall be at any time enforceable by anyone,
and such new Security shall be entitled to all the benefits of this Indenture
equally and proportionately with any and all other Securities duly issued
hereunder.

     The provisions of this Section 3.6 are exclusive and shall preclude (to the
                            -----------
extent lawful) all other rights and remedies of any Holder with respect to the
replacement or payment of mutilated, destroyed, lost or stolen Securities.

SECTION 3.7    Payment of Interest; Interest Rights Preserved.
               ----------------------------------------------

     Subject to the last paragraph of this Section, interest on any Security
which is payable, and is punctually paid or duly provided for, on any Interest
Payment Date shall be paid to the Person in whose name that Security (or one or
more Predecessor Securities) is registered at the close of business on the
Regular Record Date for such interest.

     Any interest on any Security which is payable, but is not punctually paid
or duly provided for, on any Interest Payment Date (herein called "Defaulted
Interest") shall forthwith cease to be payable to the Holder on the relevant
Regular Record Date by virtue of having been such Holder,

                                      -34-
<PAGE>

and such Defaulted Interest may be paid by the Company, at its election in each
case, as provided in Clause (1) or (2) below:

     (1)  The Company may elect to make payment of any Defaulted Interest to the
Persons in whose names the Securities (or their respective Predecessor
Securities) are registered at the close of business on a Special Record Date for
the payment of such Defaulted Interest, which shall be fixed in the following
manner.  The Company shall notify the Trustee in writing of the amount of
Defaulted Interest proposed to be paid on each Security, the date of the
proposed payment and the Special Record Date, and at the same time the Company
shall deposit with the Trustee an amount of money equal to the aggregate amount
proposed to be paid in respect of such Defaulted Interest or shall make
arrangements satisfactory to the Trustee for such deposit prior to the date of
the proposed payment, such money when deposited to be held in trust for the
benefit of the Persons entitled to such Defaulted Interest as in this Clause
provided.  The Special Record Date for the payment of such Defaulted Interest
shall be not more than 15 days and not less than 10 days prior to the date of
the proposed payment and not less than 12 days after the receipt by the Trustee
of the notice of the proposed payment.  The Trustee, in the name and at the
expense of the Company, shall cause notice of the proposed payment of such
Defaulted Interest and the Special Record Date therefor to be mailed, first-
class postage prepaid, to each Holder at such Holder's address as it appears in
the Security Register, not less than 10 days prior to such Special Record Date.
Notice of the proposed payment of such Defaulted Interest and the Special Record
Date therefor having been so mailed, such Defaulted Interest shall be paid to
the Persons in whose names the Securities (or their respective Predecessor
Securities) are registered at the close of business on such Special Record Date
and shall no longer be payable pursuant to the following Clause (2).

     (2) The Company may make payment of any Defaulted Interest in any other
lawful manner not inconsistent with the requirements of any securities exchange
on which the Securities may be listed, and upon such notice as may be required
by such exchange, if, after notice given by the Company to the Trustee of the
proposed payment pursuant to this Clause, such manner of payment shall be deemed
practicable by the Trustee.

     Subject to the foregoing and following provisions of this Section and
Section 3.5, each Security delivered under this Indenture upon registration of
-----------
transfer of or in exchange for or in lieu of any other Security shall carry the
rights to interest accrued and unpaid, and to accrue, which were carried by such
other Security.

     Interest on any Security which is converted in accordance with Section 11.2
                                                                    ------------
during a Record Date Period shall be payable in accordance with the provisions
of Section 11.2.
   ------------

                                      -35-
<PAGE>

SECTION 3.8    Persons Deemed Owners.
               ---------------------

     Prior to due presentment of a 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 of such Security
for the purpose of receiving payment of principal of, premium, if any (including
the Make-Whole Payment, if any), and (subject to Section 3.7) interest on such
                                                 -----------
Security and for all other purposes whatsoever, whether or not such Security be
overdue, and neither the Company, the Trustee nor any agent of the Company or
the Trustee shall be affected by notice to the contrary.

SECTION 3.9    Cancellation.
               ------------

     All Securities surrendered for payment, redemption, repurchase,
registration of transfer or exchange or conversion shall, if surrendered to any
Person other than the Trustee, be delivered to the Trustee.  All Securities so
delivered to the Trustee shall be canceled promptly by the Trustee.  No
Securities shall be authenticated in lieu of or in exchange for any Securities
canceled as provided in this Section 3.9.  The Trustee shall destroy all
                             -----------
canceled Securities in accordance with its customary practices in effect from
time to time and shall deliver a certificate of such destruction to the Company.

SECTION 3.10   Computation of Interest.
               -----------------------

     Interest on the Securities shall be computed on the basis of a 360-day year
of twelve 30-day months.

SECTION 3.11   CUSIP Numbers.
               -------------

     The Company in issuing Securities may use "CUSIP" numbers (if then
generally in use) in addition to serial numbers; the Trustee shall use such
CUSIP numbers in addition to serial numbers in notices of redemption and
repurchase as a convenience to Holders; provided that any such notice may state
                                        ---------
that no representation is made as to the correctness of such CUSIP numbers
either as printed on the Securities or as contained in any notice of a
redemption or repurchase and that reliance may be placed only on the serial or
other identification numbers printed on the Securities, and any such redemption
or repurchase shall not be affected by any defect in or omission of such CUSIP
numbers.  The Company shall promptly notify the Trustee in writing of any change
in any such CUSIP number.

                                      -36-
<PAGE>

                                  ARTICLE IV

                          SATISFACTION AND DISCHARGE

SECTION 4.1    Satisfaction and Discharge of Indenture.
               ---------------------------------------

     This Indenture shall upon Company Request cease to be of further effect
(except as to any surviving rights of conversion, or registration of transfer or
exchange, or replacement of Securities herein expressly provided for and the
Company's obligations to the Trustee pursuant to Section 6.7), and the Trustee,
                                                 -----------
at the expense of the Company, shall execute proper instruments in form and
substance satisfactory to the Trustee acknowledging satisfaction and discharge
of this Indenture, when

     (1)  either

          (A) all Securities theretofore authenticated and delivered (other than
(i) Securities which have been destroyed, lost or stolen and which have been
replaced or paid as provided in Section 3.6 and (ii) Securities for whose
                                -----------
payment money has theretofore been deposited in trust or segregated and held in
trust by the Company and thereafter repaid to the Company or discharged from
such trust, as provided in Section 9.3) have been delivered to the Trustee for
                           -----------
cancellation; or

          (B) all such Securities not theretofore delivered to the Trustee or
its agent for cancellation (other than Securities referred to in clauses (i) and
(ii) of clause (1)(A) above)

              (i)   have become due and payable, or

              (ii)  will have become due and payable at their Stated Maturity
within one year, or

              (iii) are to be called for redemption within one year under
arrangements satisfactory to the Trustee for the giving of notice of redemption
by the Trustee in the name, and at the expense, of the Company, and the Company,
in the case of clause (i), (ii) or (iii) of this Clause 1(B), has deposited or
caused to be deposited with the Trustee as trust funds (immediately available to
the Holders in the case of clause (i)) in trust for the purpose an amount
sufficient to pay and discharge the entire indebtedness on such Securities not
theretofore delivered to the Trustee for cancellation, for principal, premium,
if any (including the Make-Whole Payment, if any), and interest to the date of
such deposit (in the case of Securities which have become due and payable) or to
the Stated Maturity or Redemption Date, as the case may be;

                                      -37-
<PAGE>

     (2)  the Company has paid or caused to be paid all other sums payable
hereunder by the Company; and

     (3)  the Company has delivered to the Trustee an Officers' Certificate and
an Opinion of Counsel, each stating that all conditions precedent herein
provided for relating to the satisfaction and discharge of this Indenture have
been complied with.

     Notwithstanding the satisfaction and discharge of this Indenture, the
obligations of the Company to the Trustee under Section 6.7, the obligations of
                                                -----------
the Company to any Authenticating Agent under Section 6.12, the obligations of
                                              ------------
the Trustee under Section 4.2 and the last paragraph of Section 9.3 and the
                  -----------                           -----------
obligations of the Company and the Trustee under Section 3.5 and Article Eleven
                                                 -----------     --------------
shall survive.  Funds held in trust pursuant to this Section are not subject to
the provisions of Article Twelve.
                  --------------

SECTION 4.2    Application of Trust Money.
               --------------------------

     Subject to the provisions of the last paragraph of Section 9.3, all money
                                                        -----------
deposited with the Trustee pursuant to Section 4.1 shall be held in trust and
                                       -----------
applied by it, in accordance with the provisions of the Securities and this
Indenture, to the payment, either directly or through any Paying Agent
(including the Company acting as its own Paying Agent), to the Persons entitled
thereto, of the principal, premium, if any (including the Make-Whole Payment, if
any), and interest for whose payment such money has been deposited with the
Trustee.

     All moneys deposited with the Trustee pursuant to Section 4.1 (and held by
                                                       -----------
it or any Paying Agent) for the payment of Securities subsequently converted
shall be returned to the Company upon Company Request.

                                   ARTICLE V

                                   REMEDIES

SECTION 5.1    Events of Default.
               -----------------

     "Event of Default," wherever used herein, means any one of the following
events (whatever the reason for such Event of Default and whether it shall be
occasioned by the provisions of Article Twelve or be voluntary or involuntary or
                                --------------
be effected by operation of law or pursuant to any judgment, decree or order of
any court or any order, rule or regulation of any administrative or governmental
body):

     (1)  default in the payment of the principal of or premium, if any
(including the Make-Whole Payment, if any), on any Security at its Maturity,
whether or not the such payment is prohibited by the subordination provisions of
this Indenture; or

                                      -38-
<PAGE>

     (2)  default in the payment of any interest upon any Security when it
becomes due and payable, and continuance of such default for a period of 30
days, whether or not the such payment is prohibited by the subordination
provisions of this Indenture; or

     (3)  failure by the Company to give the Company Notice, if required, in
accordance with Section 13.3; or
                ------------

     (4)  default in the performance, or breach, of any covenant or warranty of
the Company in this Indenture (other than a covenant or warranty a default in
the performance or breach of which is specifically dealt with elsewhere in this
Section), and continuance of such default or breach for a period of 60 days
after there has been given, by registered or certified mail, to the Company by
the Trustee or to the Company and the Trustee by the Holders of at least 25% in
principal amount of the Outstanding Securities a written notice specifying such
default or breach and requiring it to be remedied and stating that such notice
is a "Notice of Default" hereunder; or

     (5)  a default in the payment when due (after expiration of any applicable
grace period) under any bond, debenture, note or other evidence of any
indebtedness for money borrowed by the Company or any Subsidiary of the Company
or under any mortgage, indenture or instrument under which there may be issued
or by which there may be secured or evidenced any indebtedness for money
borrowed by the Company or any Subsidiary of the Company of a principal amount
in excess of U.S. $10 million, whether such indebtedness now exists or shall
hereafter be created, or a default under any bond, debenture, note or other
evidence of indebtedness for money borrowed by the Company or any Subsidiary of
the Company or under any mortgage, indenture or instrument under which there may
be issued or by which there may be secured or evidenced any indebtedness for
money borrowed by the Company or any Subsidiary of the Company resulting in the
acceleration of such indebtedness in excess of U.S. $10 million, if the
indebtedness is not discharged, or the acceleration is not annulled, within 30
days after written notice to the Company by the Trustee or the holders of at
least 25% in aggregate principal amount of the outstanding notes; or

     (6)  the entry by a court having jurisdiction in the premises of (A) a
decree or order for relief in respect of the Company in an involuntary case or
proceeding under any applicable Federal or State bankruptcy, insolvency,
reorganization or other similar law or (B) a decree or order adjudging the
Company a bankrupt or insolvent, or approving as properly filed a petition
seeking reorganization, arrangement, adjustment or composition of or in respect
of the Company under any applicable Federal or State law, or appointing a
custodian, receiver, liquidator, assignee, trustee, sequestrator or other
similar official of the Company or of any substantial part of its property, or
ordering the winding up or liquidation of its affairs, and the continuance of
any such decree or order for relief or any such other decree or order unstayed
and in effect for a period of 90 consecutive days; or

                                      -39-
<PAGE>

     (7)  the commencement by the Company of a voluntary case or proceeding
under any applicable Federal or State bankruptcy, insolvency, reorganization or
other similar law or of any other case or proceeding to be adjudicated a
bankrupt or insolvent, or the consent by it to the entry of a decree or order
for relief in respect of the Company in an involuntary case or proceeding under
any applicable Federal or State bankruptcy, insolvency, reorganization or other
similar law or to the commencement of any bankruptcy or insolvency case or
proceeding against it, or the filing by it of a petition or answer or consent
seeking reorganization or similar relief under any applicable Federal or State
law, or the consent by it to the filing of such petition or to the appointment
of or taking possession by a custodian, receiver, liquidator, assignee, trustee,
sequestrator or other similar official of the Company or of any substantial part
of its property, or the making by it of an assignment for the benefit of
creditors, or the admission by it in writing of its inability to pay its debts
generally as they become due, or the taking of corporate action by the Company
in furtherance of any such action.

SECTION 5.2    Acceleration of Maturity; Rescission and Annulment.
               --------------------------------------------------

     If an Event of Default (other than an Event of Default specified in Section
                                                                         -------
5.1(6) or 5.1(7)) occurs and is continuing, then in every such case the Trustee
------    ------
or the Holders of not less than 25% in principal amount of the Outstanding
Securities may declare the principal of all the Securities to be due and payable
immediately, by a notice in writing to the Company (and to the Trustee if given
by the Holders), and upon any such declaration such principal and all accrued
interest thereon shall become immediately due and payable.  If an Event of
Default specified in Section 5.1(6) or 5.1(7) occurs, the principal of, and
                     --------------    ------
accrued interest on, all the Securities shall ipso facto become immediately due
                                              ---- -----
and payable without any declaration or other Act of the Holder or any act on the
part of the Trustee.

     At any time after such declaration of acceleration has been made and before
a judgment or decree for payment of the money due has been obtained by the
Trustee as hereinafter in this Article Five provided, the Holders of a majority
                               ------------
in aggregate principal amount of the Outstanding Securities, by written notice
to the Company and the Trustee, may rescind and annul such declaration and its
consequences if

     (1)  the Company has paid or deposited with the Trustee a sum sufficient to
pay

          (A) all overdue interest on all Securities,

          (B) the principal of and premium, if any (including the Make-Whole
Payment, if any), on any Securities which have become due otherwise than by such
declaration of acceleration and any interest thereon at the rate borne by the
Securities,

          (C) to the extent permitted by applicable law, interest upon overdue
interest at a rate of 4.50% per annum, and

                                      -40-
<PAGE>

          (D) all sums paid or advanced by the Trustee hereunder and the
reasonable compensation, expenses, disbursements and advances of the Trustee,
its agents and counsel; and

     (2)  all Events of Default, other than the nonpayment of the principal of,
and any premium and interest on, Securities which have become due solely by such
declaration of acceleration, have been cured or waived as provided in Section
                                                                      -------
5.13.
----

     No rescission or annulment referred to above shall affect any subsequent
default or impair any right consequent thereon.

SECTION 5.3    Collection of Indebtedness and Suits for Enforcement by Trustee.
               ---------------------------------------------------------------

     The Company covenants that if

     (1)  default is made in the payment of any interest on any Security when it
becomes due and payable and such default continues for a period of 30 days, or

     (2)  default is made in the payment of the principal of or premium, if any
(including the Make-Whole Payment, if any), on any Security at the Maturity
thereof,

the Company will upon demand of the Trustee pay to it, for the benefit of the
Holders of such Securities the whole amount then due and payable on such
Securities for principal and interest and interest on any overdue principal and
premium, if any (including the Make-Whole Payment, if any), and, to the extent
permitted by applicable law, on any overdue interest, at a rate of 4.50% per
annum, and in addition thereto, such further amount as shall be sufficient to
cover the reasonable costs and expenses of collection, including the reasonable
compensation, expenses, disbursements and advances of the Trustee, its agents
and counsel.

     If the Company fails to pay such amounts forthwith upon such demand, the
Trustee, in its own name and as trustee of an express trust, may institute a
judicial proceeding for the collection of the sums so due and unpaid, may
prosecute such proceeding to judgment or final decree and may enforce the same
against the Company or any other obligor upon the Securities and collect the
moneys adjudged or decreed to be payable in the manner provided by law out of
the property of the Company or any other obligor upon the Securities, wherever
situated.

     If an Event of Default occurs and is continuing, the Trustee may in its
discretion proceed to protect and enforce its rights and the rights of the
Holders of Securities by such appropriate judicial proceedings as the Trustee
shall deem most effectual to protect and enforce any such rights, whether for
the specific enforcement of any covenant or agreement in this Indenture or in
aid of the exercise of any power granted herein, or to enforce any other proper
remedy.

                                      -41-
<PAGE>

SECTION 5.4    Trustee May File Proofs of Claim.
               --------------------------------

     In case of the pendency of any receivership, insolvency, liquidation,
bankruptcy, reorganization, arrangement, adjustment, composition or other
judicial proceeding relative to the Company or any other obligor upon the
Securities or the property of the Company or of such other obligor or the
creditors of either, the Trustee (irrespective of whether the principal of, and
any interest on, the Securities shall then be due and payable as therein
expressed or by declaration or otherwise and irrespective of whether the Trustee
shall have made any demand on the Company for the payment of overdue principal
or interest) shall be entitled and empowered, by intervention in such proceeding
or otherwise,

     (1)  to file and prove a claim for the whole amount of principal, premium,
if any, and interest owing and unpaid in respect of the Securities and take such
other actions, including participating as a member, voting or otherwise, of any
official committee of creditors appointed in such matter, and to file such other
papers or documents, in each of the foregoing cases, as may be necessary or
advisable in order to have the claims of the Trustee (including any claim for
the reasonable compensation, expenses, disbursements and advances of the
Trustee, its agents and counsel) and of the Holders of Securities allowed in
such judicial proceeding, and

     (2)  to collect and receive any moneys or other property payable or
deliverable on any such claim and to distribute the same;

and any custodian, receiver, assignee, trustee, liquidator, sequestrator or
other similar official in any such judicial proceeding is hereby authorized by
each Holder of Securities to make such payments to the Trustee and, in the event
that the Trustee shall consent to the making of such payments directly to the
Holders of Securities, to pay to the Trustee any amount due to it for the
reasonable compensation, expenses, disbursements and advances of the Trustee,
its agents and counsel and any other amounts due the Trustee under Section 6.7.
                                                                   -----------

     Nothing herein contained shall be deemed to authorize the Trustee to
authorize or consent to or accept or adopt on behalf of any Holder of a Security
any plan of reorganization, arrangement, adjustment or composition affecting the
Securities or the rights of any Holder thereof or to authorize the Trustee to
vote in respect of the claim of any Holder of a Security in any such proceeding;
provided, however, that the Trustee may, on behalf of such Holders, vote for the
 -------  -------
election of a trustee in bankruptcy or similar official.

SECTION 5.5    Trustee May Enforce Claims Without Possession of Securities.
               -----------------------------------------------------------

     All rights of action and claims under this Indenture (including the amounts
provided for in Section 6.7) or the Securities may be prosecuted and enforced by
the Trustee without the possession of any of the Securities or the production
thereof in any proceeding relating thereto, and any such proceeding instituted
by the Trustee shall be brought in its own name as trustee of

                                      -42-
<PAGE>

an express trust, and any recovery of judgment shall, after provision for the
payment of the reasonable compensation, expenses, disbursements and advances of
the Trustee, its agents and counsel, be for the ratable benefit of the Holders
of the Securities in respect of which judgment has been recovered.

SECTION 5.6    Application of Money Collected.
               ------------------------------

     Subject to Article Twelve, any money collected by the Trustee pursuant to
                --------------
this Article Five shall be applied in the following order, at the date or dates
     ------------
fixed by the Trustee and, in case of the distribution of such money on account
of principal, premium, if any (including the Make-Whole Payment, if any), or
interest, upon presentation of the Securities and the notation thereon of the
payment if only partially paid and upon surrender thereof if fully paid:

     FIRST: To the payment of all amounts due the Trustee under Section 6.7;
                                                                -----------

     SECOND: To the payment of the amounts then due and unpaid for principal of,
premium, if any (including the Make-Whole Payment, if any), or interest on, the
Securities in respect of which or for the benefit of which such money has been
collected, ratably, without preference or priority of any kind, according to the
amounts due and payable on such Securities for principal, premium, if any
(including the Make-Whole Payment, if any), and interest, respectively; and

     THIRD: Any remaining amounts shall be repaid to the Company.

SECTION 5.7    Limitation on Suits.
               -------------------

     No Holder of any Security shall have any right to institute any proceeding,
judicial or otherwise, with respect to this Indenture, or for the appointment of
a receiver or trustee, or for any other remedy hereunder, unless:

     (1)  such Holder has previously given written notice to the Trustee of an
Event of Default that is continuing at the time of such institution;

     (2)  the Holders of not less than 25% in aggregate principal amount of the
Outstanding Securities shall have made written request to the Trustee to
institute proceedings in respect of such Event of Default in its own name as
Trustee hereunder;

     (3)  such Holder or Holders have furnished to the Trustee reasonable
indemnity against the costs, expenses and liabilities to be incurred in
compliance with such request; and

     (4)  the Trustee for 60 days after its receipt of such notice, request and
furnishing of indemnity has failed to institute any such proceeding;

                                      -43-
<PAGE>

it being understood and intended that no one or more of such Holders shall have
any right in any manner whatever by virtue of, or by availing of, any provision
of this Indenture to affect, disturb or prejudice the rights of any other of
such Holders, or to obtain or seek to obtain priority or preference over any
other of such Holders or to enforce any right under this Indenture, except in
the manner herein provided and for the equal and ratable benefit of all such
Holders.

SECTION 5.8    Unconditional Right of Holders to Receive Principal, Premium and
               ----------------------------------------------------------------
               Interest and to Convert.
               -----------------------

     Notwithstanding any other provision in this Indenture, the Holder of any
Security shall have the right, which is absolute and unconditional, to receive
payment of the principal of, premium, if any (including the Make-Whole Payment,
if any), and (subject to Section 3.7) interest on such Security on the
                         -----------
respective Stated Maturities expressed in such Security (or, in the case of
redemption or repurchase, on the Redemption Date or Repurchase Date, as the case
may be), and to convert such Security in accordance with Article Eleven, and to
                                                         --------------
institute suit for the enforcement of any such payment and right to convert, and
such rights shall not be impaired without the consent of such Holder.

SECTION 5,9    Restoration of Rights and Remedies.
               ----------------------------------

     If the Trustee or any Holder of a Security has instituted any proceeding to
enforce any right or remedy under this Indenture and such proceeding has been
discontinued or abandoned for any reason, or has been determined adversely to
the Trustee or to such Holder, then and in every such case, subject to any
determination in such proceeding, the Company, the Trustee and the Holders of
Securities shall be restored severally and respectively to their former
positions hereunder and thereafter all rights and remedies of the Trustee and
such Holders shall continue as though no such proceeding had been instituted.

SECTION 5.10   Rights and Remedies Cumulative.
               ------------------------------

     Except as otherwise provided with respect to the replacement or payment of
mutilated, destroyed, lost or stolen Securities in the last paragraph of Section
                                                                         -------
3.6, no right or remedy herein conferred upon or reserved to the Trustee or to
---
the Holders of Securities is intended to be exclusive of any other right or
remedy, and every right and remedy shall, to the extent permitted by law, be
cumulative and in addition to every other right and remedy given hereunder or
now or hereafter existing at law or in equity or otherwise.  The assertion or
employment of any right or remedy hereunder, or otherwise, shall not prevent the
concurrent assertion or employment of any other appropriate right or remedy.

                                      -44-
<PAGE>

SECTION 5.11   Delay or Omission Not Waiver.
               ----------------------------

     No delay or omission of the Trustee or of any Holder of any Security to
exercise any right or remedy accruing upon any Event of Default shall impair any
such right or remedy or constitute a waiver of any such Event of Default or any
acquiescence therein.  Every right and remedy given by this Article Five or by
                                                            ------------
law to the Trustee or to the Holders of Securities may be exercised from time to
time, and as often as may be deemed expedient, by the Trustee or (subject to the
limitations contained in this Indenture) by the Holders of Securities as the
case may be.

SECTION 5.12   Control by Holders of Securities.
               --------------------------------

     The Holders of a majority in principal amount of the Outstanding Securities
shall have the right to direct the time, method and place of conducting any
proceeding for any remedy available to the Trustee or exercising any trust or
power conferred on the Trustee, provided that
                                --------

     (1)  such direction shall not be in conflict with any rule of law or with
this Indenture, and

     (2)  the Trustee may take any other action deemed proper by the Trustee
which is not inconsistent with such direction.

In the event of such direction, the Trustee shall have no duty to ascertain
whether such actions or forbearances are unduly prejudicial to any Holders.

SECTION 5.13   Waiver of Past Defaults.
               -----------------------

     The Holders, either (a) through the written consent of not less than a
majority in principal amount of the Outstanding Securities, 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 a majority in principal
amount of the Outstanding Securities represented at such meeting, may on behalf
of the Holders of all the Securities waive any past default hereunder and its
consequences, except a default (1) in the payment of the principal of, premium,
if any (including the Make-Whole Payment, if any), or interest on any Security,
or (2) in respect of a covenant or provision hereof which under Article Eight
                                                                -------------
cannot be modified or amended without the consent of the Holder of each
Outstanding Security affected.

     Upon any such waiver, such default shall cease to exist, and any Event of
Default arising therefrom shall be deemed to have been cured, for every purpose
of this Indenture; but no such waiver shall extend to any subsequent or other
default or impair any right consequent thereon.

                                      -45-
<PAGE>

SECTION 5.14   Undertaking for Costs.
               ---------------------

     All parties to this Indenture agree, and each Holder of any Security by its
acceptance thereof shall be deemed to have agreed, that any court may in its
discretion require, in any suit for the enforcement of any right or remedy under
this Indenture, or in any suit against the Trustee for any action taken,
suffered or omitted by it as Trustee, the filing by any party litigant in such
suit of an undertaking to pay the costs of such suit, and that such court may in
its discretion assess reasonable costs, including reasonable attorneys' fees and
expenses, against any party litigant in such suit, having due regard to the
merits and good faith of the claims or defenses made by such party litigant; but
the provisions of this Section 5.14 shall not apply to any suit instituted by
                       -------------
the Company, to any suit instituted by the Trustee, to any suit instituted by
any Holder, or group of Holders, holding in the aggregate more than 10% in
principal amount of the Outstanding Securities, or to any suit instituted by any
Holder of any Security for the enforcement of the payment of the principal of,
premium, if any, or interest on any Security on or after the respective Stated
Maturity or Maturities expressed in such Security (or, in the case of redemption
or repurchase, on or after the Redemption Date or Repurchase Date, as the case
may be) or for the enforcement of the right to convert any Security in
accordance with Article Eleven.
                --------------

                                  ARTICLE VI

                                  THE TRUSTEE

SECTION 6.1    Certain Duties and Responsibilities.
               -----------------------------------

     (a)  Except during the continuance of an Event of Default,

          (1) the Trustee undertakes to perform such duties and only such duties
as are specifically set forth in this Indenture, and no implied covenants or
obligations shall be read into this Indenture against the Trustee; and

          (2) in the absence of bad faith on its part, the Trustee may
conclusively rely, as to the truth of the statements and the correctness of the
opinions expressed therein, upon certificates or opinions furnished to the
Trustee and conforming to the requirements of this Indenture; but in the case of
any such certificates or opinions which by any provision hereof are specifically
required to be furnished to the Trustee, the Trustee shall be under a duty to
examine the same to determine whether or not they conform on their face to the
requirements of this Indenture, but not to verify the contents thereof.

     (b)  In case an Event of Default has occurred and is continuing, the
Trustee shall exercise such of the rights and powers vested in it by this
Indenture, and use the same degree of care and skill in their exercise, as a
prudent man would exercise or use under the circumstances in the conduct of his
own affairs.

                                      -46-
<PAGE>

     (c)  No provision of this Indenture shall be construed to relieve the
Trustee from liability for its own negligent action, its own negligent failure
to act, or its own willful misconduct, except that
                                       ------

          (1) this paragraph (c) shall not be construed to limit the effect of
paragraph (a) of this Section;

          (2) the Trustee shall not be liable for any error of judgment made in
good faith by a Responsible Officer, unless it shall be proved that the Trustee
was negligent in ascertaining the pertinent facts;

          (3) the Trustee shall not be liable with respect to any action taken
or omitted to be taken by it in good faith in accordance with the direction of
the Holders of a majority in aggregate principal amount of the Outstanding
Securities relating to the time, method and place of conducting any proceeding
for any remedy available to the Trustee, or exercising any trust or power
conferred upon the Trustee, under this Indenture;

          (4) no provision of this Indenture shall require the Trustee to expend
or risk its own funds or otherwise incur any financial liability in the
performance of any of its duties hereunder, or in the exercise of any of its
rights or powers, if it shall have reasonable grounds for believing that
repayment of such funds or adequate indemnity against such risk or liability is
not reasonably assured to it; and

          (5) the Trustee shall not be liable for interest on any money received
by it acting in its capacity as Trustee hereunder except as the Trustee may
agree in writing with the Company.

     (d)  In the absence of negligence or willful misconduct on the part of the
Trustee, the Trustee shall not be responsible for the applications of any money
by any Paying Agent other than the Trustee.

     (e)  Whether or not therein expressly so provided, every provision of this
Indenture relating to the conduct or affecting the liability of or affording
protection to the Trustee shall be subject to the provisions of this Section and
the Trust Indenture Act.

SECTION 6.2    Notice of Defaults.
               ------------------

     Within 90 days after a Responsible Officer becomes aware of the occurrence
of any default hereunder as to which the Trustee has actually received written
notice, the Trustee shall give to all Holders of Securities, in the manner
provided in Section 1.6, notice of such default, unless such default shall have
            -----------
been cured or waived; provided, however, that, except in the case of a default
                      --------  -------
in the payment of the principal of, premium, if any, or interest on any Security
the

                                      -47-
<PAGE>

Trustee shall be protected in withholding such notice if and so long as the
board of directors, the executive committee or a trust committee of directors or
Responsible Officers of the Trustee in good faith determine that the withholding
of such notice is in the interest of the Holders; and provided, further, that in
                                                      --------  -------
the case of any default of the character specified in Section 5.1(4), no such
                                                      --------------
notice to Holders of Securities shall be given until at least 60 days after the
occurrence thereof.  For the purpose of this Section, the term "default" means
any event which is, or after notice or lapse of time or both would become, an
Event of Default.

SECTION  6.3   Certain Rights of Trustee.
               -------------------------

     Subject to the provisions of Section 6.1:
                                  -----------

     (1)  the Trustee may rely and shall be protected in acting or refraining
from acting upon any resolution, Officers' Certificate, other certificate,
statement, instrument, opinion, report, notice, request, direction, consent,
order, bond, debenture, note, coupon, other evidence of indebtedness or other
paper or document believed by it to be genuine and to have been signed or
presented by the proper party or parties;

     (2)  any request or direction of the Company mentioned herein shall be
sufficiently evidenced by a Company Request or Company Order and any resolution
of the Board of Directors shall be sufficiently evidenced by a Board Resolution;

     (3)  whenever in the administration of this Indenture the Trustee shall
deem it desirable that a matter be proved or established prior to taking,
suffering or omitting any action hereunder, the Trustee (unless other evidence
be herein specifically prescribed) may, in the absence of bad faith on its part,
request and rely upon an Officers' Certificate and the Trustee shall not be
liable for any action it takes or omits to take in good faith in reliance on the
Officer's Certificate;

     (4)  the Trustee may consult with counsel of its selection (at the expense
of the Company) and the advice of such counsel or any Opinion of 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 reliance
thereon;

     (5)  the Trustee shall be under no obligation to exercise any of the rights
or powers vested in it by this Indenture at the request or direction of any of
the Holders of Securities pursuant to this Indenture, unless such Holders shall
have furnished to the Trustee reasonable security or indemnity against the
costs, expenses and liabilities which might be incurred by it in compliance with
such request or direction;

     (6)  the Trustee shall not be bound to make any investigation into the
facts or matters stated in any resolution, certificate, statement, instrument,
opinion, report, notice, request,

                                      -48-
<PAGE>

direction, consent, order, bond, debenture, note, coupon, other evidence of
indebtedness or other paper or document, but the Trustee may make such further
inquiry or investigation into such facts or matters as it may see fit, and, if
the Trustee shall determine to make such further inquiry or investigation, it
shall be entitled to examine the books, records and premises of the Company,
personally or by agent or attorney;

     (7)  the Trustee may execute any of the trusts or powers hereunder or
perform any duties hereunder either directly or by or through agents or
attorneys and the Trustee shall not be responsible for any misconduct or
negligence on the part of any agent or attorney appointed with due care by it
hereunder;

     (8)  the Trustee shall not be liable for any action it takes or omits to
take in good faith which it reasonably believes to be authorized or within its
rights or powers; provided, however, that the Trustee's action or omission does
                  --------  -------
not constitute willful misconduct or negligence;

     (9)  any permissive right of the Trustee hereunder shall not be construed
to be a duty; and

     (10) the Trustee shall not be charged with knowledge of any Event of
Default, other than as described in Section 5.1(1) or (2), unless and except to
                                    --------------    ---
the extent actually known to a Responsible Officer or written notice thereof is
received by the Trustee at its Corporate Trust Office.

SECTION 6.4    Not Responsible for Recitals or Issuance of Securities.
               ------------------------------------------------------

     The recitals contained herein and in the Securities (except the Trustee's
certificates of authentication) shall be taken as the statements of the Company,
and the Trustee assumes no responsibility for their correctness.  The Trustee
makes no representations as to the validity or sufficiency of this Indenture, of
the Securities or of the Common Stock issuable upon the conversion of the
Securities.  The Trustee shall not be accountable for the use or application by
the Company of Securities or the proceeds thereof.

SECTION 6.5    May Hold Securities, Act as Trustee Under Other Indentures.
               ----------------------------------------------------------

     The Trustee, any Authenticating Agent, any Paying Agent, any Conversion
Agent or any other agent of the Company or the Trustee, in its individual or any
other capacity, may become the owner or pledgee of Securities and may otherwise
deal with the Company with the same rights it would have if it were not Trustee,
Authenticating Agent, Paying Agent, Conversion Agent or such other agent.

                                      -49-
<PAGE>

     The Trustee may become and act as trustee under other indentures under
which other securities, or certificates of interest or participation in other
securities, of the Company are outstanding in the same manner as if it were not
Trustee hereunder.

SECTION 6.6    Money Held in Trust.
               -------------------

     Money held by the Trustee in trust hereunder need not be segregated from
other funds except to the extent required by law.  The Trustee shall be under no
liability for interest on any money received by it hereunder except as otherwise
agreed in writing with the Company.

SECTION 6.7    Compensation and Reimbursement.
               ------------------------------

     The Company agrees

     (1)  pay to the Trustee from time to time such compensation as the Company
and the Trustee shall from time to time agree in writing for all services
rendered by it hereunder (which compensation shall not be limited by any
provision of law in regard to the compensation of a trustee of an express
trust);

     (2)  except as otherwise expressly provided herein, to reimburse the
Trustee upon its request for all reasonable expenses, disbursements and advances
incurred or made by the Trustee in accordance with any provision of this
Indenture (including the reasonable compensation and the expenses and
disbursements of its agents, accountants, experts and counsel), except any such
expense, disbursement or advance as may be attributable to its negligence or bad
faith; and

     (3)  to indemnify the Trustee (and its directors, officers, employees and
agents) for, and to hold it harmless against, any and all loss, damage, claim,
liability or expense, including taxes (other than taxes based on the income of
the Trustee), incurred without negligence or bad faith on its part, arising out
of or in connection with the acceptance or administration of this trust,
including the reasonable costs, expenses and reasonable attorneys' fees of
defending itself against any claim or liability in connection with the exercise
or performance of any of its powers or duties hereunder.

     When the Trustee incurs expenses or renders services in connection with an
Event of Default specified in Section 5.1(6) or Section 5.1(7), the expenses
                              --------------    --------------
(including the reasonable charges of its counsel) and the compensation for the
services are intended to constitute expenses of the administration under any
applicable Federal or State bankruptcy, insolvency or other similar law.

     The Trustee is hereby granted a security interest in and a lien prior to
the Securities as to all property and funds held by it hereunder for any amount
owing it or any predecessor Trustee

                                      -50-
<PAGE>

pursuant to this Section 6.7, except with respect to funds held in trust for the
                 -----------
benefit of the Holders of particular Securities.

     The provisions of this Section shall survive the termination of this
Indenture or the earlier resignation or removal of the Trustee.

SECTION 6.8    Corporate Trustee Required; Eligibility.
               ---------------------------------------

     There shall at all times be a Trustee hereunder which shall be a Person
that is eligible pursuant to the Trust Indenture Act to act as such, having a
combined capital and surplus of at least U.S.$250,000,000, subject to
supervision or examination by Federal or State authority, in good standing and
having an established place of business in the Borough of Manhattan, The City of
New York.  If such corporation publishes reports of condition at least annually,
pursuant to law or to the requirements of said supervising or examining
authority, then for the purposes of this Section, the combined capital and
surplus of such corporation shall be deemed to be its combined capital and
surplus as set forth in its most recent report of condition so published. If at
any time the Trustee shall cease to be eligible in accordance with the
provisions of this Section, it shall resign immediately in the manner and with
the effect hereinafter specified in this Article and a successor shall be
appointed pursuant to Section 6.9.
                      -----------

SECTION 6.9    Resignation and Removal; Appointment of Successor.
               -------------------------------------------------

          (a)  No resignation or removal of the Trustee and no appointment of a
successor Trustee pursuant to this Article shall become effective until the
acceptance of appointment by the successor Trustee in accordance with the
applicable requirements of Section 6.10.
                           ------------

          (b)  The Trustee may resign at any time by giving written notice
thereof to the Company. If the instrument of acceptance by a successor Trustee
required by Section 6.10 shall not have been delivered to the Trustee within 30
            ------------
days after the giving of such notice of resignation, the resigning Trustee may
petition any court of competent jurisdiction for the appointment of a successor
Trustee.

          (c)  The Trustee may be removed at any time by Act of the Holders of a
majority in aggregate principal amount of the Outstanding Securities, delivered
to the Trustee and the Company.  If the instrument of acceptance by a successor
Trustee required by Section 6.10 shall not have been delivered to the Trustee
                    ------------
within 30 days after the giving of such notice of removal, the removed Trustee
may petition any court of competent jurisdiction for the appointment of a
successor Trustee.

                                      -51-
<PAGE>

          (d)  If at any time:

               (1) the Trustee shall cease to be eligible under Section 6.8 and
                                                                -----------
shall fail to resign after written request therefor by the Company or by any
Holder of a Security who has been a bona fide Holder of a Security for at least
six months, or

               (2) the Trustee shall become incapable of acting or shall be
adjudged a bankrupt or insolvent or a receiver of the Trustee or of its property
shall be appointed or any public officer shall take charge or control of the
Trustee or of its property or affairs for the purpose of rehabilitation,
conservation or liquidation,

then, in any such case (i) the Company by a Board Resolution may remove the
Trustee, or (ii) subject to Section 5.14, any Holder of a Security who has been
                            ------------
a bona fide Holder of a Security for at least six months may, on behalf of
himself and all others similarly situated, petition any court of competent
jurisdiction for the removal of the Trustee and the appointment of a successor
Trustee.

          (e)  If the Trustee shall resign, be removed or become incapable of
acting, or if a vacancy shall occur in the office of Trustee for any cause, the
Company, by a Board Resolution, shall promptly appoint a successor Trustee and
shall comply with the applicable requirements of this Section and Section 6.10.
                                                                  ------------
If, within one year after such resignation, removal or incapability, or
occurrence of such vacancy, a successor Trustee shall be appointed by Act of the
Holders of a majority in aggregate principal amount of the Outstanding
Securities delivered to the Company and the retiring Trustee, the successor
Trustee so appointed shall, forthwith upon its acceptance of such appointment in
accordance with the applicable requirements of Section 6.10 become the successor
                                               ------------
Trustee and supersede the successor Trustee appointed by the Company. If no
successor Trustee shall have been so appointed by the Company or the Holders of
Securities and accepted appointment in the manner required by this Section and
Section 6.10, any Holder of a Security who has been a bona fide Holder of a
------------
Security for at least six months may, on behalf of himself and all others
similarly situated, petition any court of competent jurisdiction for the
appointment of a successor Trustee.

          (f)  The Company shall give notice of each resignation and each
removal of the Trustee and each appointment of a successor Trustee to all
Holders of Securities in the manner provided in Section 1.6. Each notice shall
                                                -----------
include the name of the successor Trustee and the address of its Corporate Trust
Office.

SECTION 6.10   Acceptance of Appointment by Successor.
               --------------------------------------

          Every successor Trustee appointed hereunder shall execute, acknowledge
and deliver to the Company and to the retiring Trustee an instrument accepting
such appointment, and thereupon the resignation or removal of the retiring
Trustee shall become effective and such

                                      -52-
<PAGE>

successor Trustee, without any further act, deed or conveyance, shall become
vested with all the rights, powers, trusts and duties of the retiring Trustee;
but, on the request of the Company or the successor Trustee, such retiring
Trustee shall, upon payment of its charges, execute and deliver an instrument
transferring to such successor Trustee all the rights, powers and trusts of the
retiring Trustee and shall duly assign, transfer and deliver to such successor
Trustee all property and money held by such retiring Trustee hereunder, subject
to the lien provided for in Section 6.7. Upon request of any such successor
Trustee, the Company shall execute any and all instruments for more fully and
certainly vesting in and confirming to such successor Trustee all such rights,
powers and trusts.

     No successor Trustee shall accept its appointment unless at the time of
such acceptance such successor Trustee shall be eligible under this Article.

SECTION 6.11   Merger, Conversion, Consolidation or Succession to Business.
               -----------------------------------------------------------

     Any corporation into which the Trustee may be merged or converted or with
which it may be consolidated, or any corporation resulting from any merger,
conversion or consolidation to which the Trustee shall be a party, or any
corporation succeeding to all or substantially all of the corporate trust
business of the Trustee, shall be the successor of the Trustee hereunder,
provided such corporation shall be otherwise eligible under this Article,
--------
without the execution or filing of any paper or any further act on the part of
any of the parties hereto.  In case any Securities shall have been
authenticated, but not delivered, by the Trustee then in office, any successor
by merger, conversion or consolidation to such authenticating Trustee may adopt
such authentication and deliver the Securities so authenticated with the same
effect as if such successor Trustee had itself authenticated such Securities.

SECTION 6.12   Authenticating Agents.
               ---------------------

     The Trustee may, with the consent of the Company, appoint an Authenticating
Agent or Agents acceptable to the Company with respect to the Securities which
shall be authorized to act on behalf of the Trustee to authenticate Securities
issued upon exchange or substitution pursuant to this Indenture.

     Securities authenticated by an Authenticating Agent shall be entitled to
the benefits of this Indenture and shall be valid and obligatory for all
purposes as if authenticated by the Trustee hereunder, and every reference in
this Indenture to the authentication and delivery of Securities by the Trustee
or the Trustee's certificate of authentication shall be deemed to include
authentication and delivery on behalf of the Trustee by an Authenticating Agent
and a certificate of authentication executed on behalf of the Trustee by an
Authenticating Agent.  Each Authenticating Agent shall be subject to acceptance
by the Company and shall at all times be a corporation organized and doing
business under the laws of the United States of America, any State thereof or
the District of Columbia, authorized under such laws to act as Authenticating

                                      -53-
<PAGE>

Agent and subject to supervision or examination by government or other fiscal
authority.  If at any time an Authenticating Agent shall cease to be eligible in
accordance with the provisions of this Section 6.12 such Authenticating Agent
                                       ------------
shall resign immediately in the manner and with the effect specified in this
Section 6.12.
------------

     Any corporation into which an Authenticating Agent may be merged or
converted or with which it may be consolidated, or any corporation resulting
from any merger, conversion or consolidation to which such Authenticating Agent
shall be a party, or any corporation succeeding to the corporate agency or
corporate trust business of an Authenticating Agent, shall continue to be an
Authenticating Agent, provided such corporation shall be otherwise eligible
                      --------
under this Section 6.12, without the execution or filing of any paper or any
           ------------
further act on the part of the Trustee or the Authenticating Agent.

     An Authenticating Agent may resign at any time by giving written notice
thereof to the Trustee and to the Company.  The Trustee may at any time
terminate the agency of an Authenticating Agent by giving written notice thereof
to such Authenticating Agent and to the Company.  Upon receiving such a notice
of resignation or upon such a termination, or in case at any time such
Authenticating Agent shall cease to be eligible in accordance with the
provisions of this Section 6.12, the Trustee may appoint a successor
                   ------------
Authenticating Agent which shall be subject to acceptance by the Company.  Any
successor Authenticating Agent upon acceptance of its appointment hereunder
shall become vested with all the rights, powers and duties of its predecessor
hereunder, with like effect as if originally named as an Authenticating Agent.
No successor Authenticating Agent shall be appointed unless eligible under the
provisions of this Section 6.12.
                   ------------

     The Company agrees to pay to each Authenticating Agent from time to time
reasonable compensation for its services under this Section 6.12.
                                                    ------------

     If an Authenticating Agent is appointed with respect to the Securities
pursuant to this Section 6.12, the Securities may have endorsed thereon, in
                 ------------
addition to or in lieu of the Trustee's certification of authentication, an
alternative certificate of authentication in the following form:

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

                              Wilmington Trust Company,
                              as Trustee
                              By [Authenticating Agent],
                              as Authenticating Agent

                              By  ___________________________________
                                    Authorized Signature

                                      -54-
<PAGE>

SECTION 6.13   Disqualification; Conflicting Interests.
               ---------------------------------------

     If the Trustee has or shall acquire a conflicting interest within the
meaning of the Trust Indenture Act, the Trustee shall either eliminate such
interest or resign, to the extent and in the manner provided by, and subject to
the provisions of, the Trust Indenture Act and this Indenture.

SECTION 6.14   Preferential Collection of Claims Against Company.
               -------------------------------------------------

     If and when the Trustee shall be or become a creditor of the Company (or
any other obligor upon the Securities), the Trustee shall be subject to the
provisions of the Trust Indenture Act regarding the collection of claims against
the Company (or any such other obligor).

                                  ARTICLE VII

             CONSOLIDATION, MERGER, CONVEYANCE, TRANSFER OR LEASE

SECTION 7.1    Company May Consolidate, Etc., Only on Certain Terms.
               ----------------------------------------------------

     The Company shall not consolidate with or merge into any other Person or
convey, transfer or lease all its properties and assets substantially as an
entirety to any Person, and the Company shall not permit any Person to
consolidate with or merge into the Company or convey, transfer or lease all or
substantially all of its properties and assets substantially as an entirety to
the Company, unless:

     (1)  in case the Company shall consolidate with or merge into another
Person or convey, transfer or lease its properties and assets substantially as
an entirety to any Person, the Person formed by such consolidation or into which
the Company is merged, or the Person which acquires by conveyance or transfer,
or which leases the properties and assets of the Company substantially as an
entirety, shall (i) be a corporation, limited liability company, partnership or
trust, (ii) shall be an entity (A) organized and validly existing under the laws
of the United States of America, any State thereof or the District of Columbia
or (B) organized and validly existing under the laws of jurisdiction outside of
the United States of America, with its common stock, or American Depositary
Shares representing such shares of common stock, traded on a national securities
exchange in the United States of America or through Nasdaq and an average
worldwide total market capitalization of its equity securities, before giving
effect to such Merger of consolidation, of at least U.S. $5 billion during the
five consecutive Trading Days immediately preceding the date of the transaction
and (iii)  shall expressly assume, by an indenture supplemental hereto, executed
and delivered to the Trustee, in form satisfactory to the Trustee, the due and
punctual payment of the principal of, premium, if any (including the Make-Whole
Payment, if any), and interest on all of the Securities as applicable, and the
performance or observance of every covenant of this Indenture on the part of the
Company to be performed or

                                      -55-
<PAGE>

observed and shall have provided for conversion rights substantially in
accordance with Article Eleven;
                --------------

     (2)  immediately after giving effect to such transaction, no Event of
Default, and no event that after notice or lapse of time or both, would become
an Event of Default, shall have happened and be continuing; and

     (3)  the Company has delivered to the Trustee an Officers' Certificate and
an Opinion of Counsel, each stating that such consolidation, merger, conveyance,
transfer or lease and, if a supplemental indenture is required in connection
with such transaction, such supplemental indenture comply with this Article and
that all conditions precedent provided for in this Article relating to such
transaction have been complied with, together with any documents required under
Section 8.3.
-----------

SECTION 7.2    Successor Substituted.
               ---------------------

     Upon any consolidation of the Company with, or merger of the Company into
any other Person or any conveyance, transfer or lease of the properties and
assets of the Company substantially as an entirety in accordance with Section
                                                                      -------
7.1, the successor Person formed by such consolidation or into or with which the
---
Company is merged or to which such conveyance, transfer or lease is made shall
succeed to, and be substituted for, and may exercise every right and power of,
the Company under this Indenture with the same effect as if such successor
Person had been named as the Company herein, and thereafter, except in the case
of a lease, the predecessor Person shall be relieved of all obligations and
covenants under this Indenture and the Securities.

                                 ARTICLE VIII

                            SUPPLEMENTAL INDENTURES

SECTION 8.1    Supplemental Indentures Without Consent of Holders of Securities.
               ----------------------------------------------------------------

     Without the consent of any Holders of Securities, the Company, when
authorized by a Board Resolution, and the Trustee, at any time and from time to
time, may enter into one or more indentures supplemental hereto for any of the
following purposes:

     (1)  to evidence the succession of another Person to the Company and the
assumption by any such successor of the covenants and obligations of the Company
herein and in the Securities as permitted by this Indenture; or

     (2)  to add to the covenants of the Company for the benefit of the Holders
of Securities or to surrender any right or power herein conferred upon the
Company; or

                                      -56-
<PAGE>

     (3)  to secure the Securities; or

     (4)  to make provision with respect to the conversion rights of Holders of
Securities pursuant to Section 11.11; or
                       -------------

     (5)  to comply with the requirements of the Trust Indenture Act or the
rules and regulations of the Commission thereunder in order to effect or
maintain the qualification of this Indenture under the Trust Indenture Act, as
contemplated by this Indenture or otherwise; or

     (6)  to evidence and provide for the acceptance of appointment hereunder by
a successor Trustee; or

     (7)  to cure any ambiguity, to correct or supplement any provision herein
which may be inconsistent with any other provision herein or which is otherwise
defective, or to make any other provisions with respect to matters or questions
arising under this Indenture as the Company and the Trustee may deem necessary
or desirable, provided such action pursuant to this clause (7) shall not
              --------
adversely affect the interests of the Holders of Securities in any material
respect.

     Upon Company Request, accompanied by a Board Resolution authorizing the
execution of any such supplemental indenture, and subject to and upon receipt by
the Trustee of the documents described in Section 8.3 hereof, the Trustee shall
                                          -----------
join with the Company in the execution of any supplemental indenture authorized
or permitted by the terms of this Indenture and to make any further appropriate
agreements and stipulations which may be therein contained.

SECTION 8.2    Supplemental Indentures with Consent of Holders of Securities.
               -------------------------------------------------------------

     With either (a) the written consent of the Holders of not less than a
majority in principal amount of the Outstanding Securities, by the Act of said
Holders delivered to the Company and the Trustee, or (b) the adoption of a
resolution, at a meeting of Holders of the Outstanding Securities at which a
quorum is present, by the Holders of a majority in principal amount of the
Outstanding Securities represented at such meeting, the Company, when authorized
by a Board Resolution, and the Trustee may enter into an indenture or indentures
supplemental hereto for the purpose of adding any provisions to or changing in
any manner or eliminating any of the provisions of this Indenture or of
modifying in any manner the rights of the Holders of Securities under this
Indenture; provided, however, that no such supplemental indenture shall, without
           -----------------
the consent or affirmative vote of the Holder of each Outstanding Security
affected thereby,

     (1)  change the Stated Maturity of the principal of, or any installment of
interest on, any Security, or reduce the principal amount or the rate of
interest payable thereon or any amount (including the Make-Whole Payment)
payable upon redemption or repurchase pursuant to Article Thirteen thereof, or
                                                  ----------------
change the place at which any payment on any Security is payable, or change the
coin or currency in which any Security or the interest or any premium (including
the

                                      -57-
<PAGE>

Make-Whole Payment) thereon or any other amount in respect thereof is payable,
or impair the right to institute suit for the enforcement of any payment in
respect of any Security on or after the Stated Maturity thereof (or, in the case
of redemption or any repurchase, on or after the Redemption Date or Repurchase
Date, as the case may be) or, except as permitted by Section 11.11, adversely
                                                     -------------
affect the right to convert any Security as provided in Article Eleven, or
                                                        --------------
modify the provisions of this Indenture with respect to the subordination of the
Securities in a manner adverse to the Holders of Securities; or

     (2)  reduce the percentage in principal amount of the Outstanding
Securities the consent of whose Holders is required for any such supplemental
indenture or the consent of whose Holders is required for any waiver (of
compliance with certain provisions of this Indenture or certain defaults
hereunder and their consequences) provided for in this Indenture; or

     (3)  modify any of the provisions of this Section and Section 5.13 except
                                                           ------------
to increase any percentage contained herein or therein or to provide that
certain other provisions of this Indenture cannot be modified or waived without
the consent of the Holder of each Outstanding Security affected thereby; or

     (4)  modify the provisions of Article Thirteen in a manner adverse to the
                                   ----------------
Holders; or

     (5)  modify any of the provisions of Section 9.8.
                                          -----------

     It shall not be necessary for any Act of Holders of Securities under this
Section to approve the particular form of any proposed supplemental indenture,
but it shall be sufficient if such Act shall approve the substance thereof.

SECTION 8.3    Execution of Supplemental Indentures.
               ------------------------------------

     In executing, or accepting the additional trusts created by, any
supplemental indenture permitted by this Article or the modifications thereby of
the trusts created by this Indenture, the Trustee shall be entitled to receive,
and (subject to Sections 6.1 and 6.3) shall be fully protected in relying upon,
                ------------     ---
an Opinion of Counsel stating that the execution of such supplemental indenture
is authorized or permitted by this Indenture, and that such supplemental
indenture has been duly authorized, executed and delivered by the Company and
constitutes a valid and legally binding obligation of the Company enforceable
against the Company in accordance with its terms.  The Trustee may, but shall
not be obligated to, enter into any such supplemental indenture which affects
the Trustee's own rights, duties or immunities under this Indenture or
otherwise.

                                      -58-
<PAGE>

SECTION 8.4    Effect of Supplemental Indentures.
               ---------------------------------

     Upon the execution of any supplemental indenture under this Article, this
Indenture shall be modified in accordance therewith, and such supplemental
indenture shall form a part of this Indenture for all purposes; and every Holder
of Securities theretofore or thereafter authenticated and delivered hereunder
appertaining thereto shall be bound thereby.

SECTION 8.5    Reference in Securities to Supplemental Indentures.
               --------------------------------------------------

     Securities authenticated and delivered after the execution of any
supplemental indenture pursuant to this Article may, and shall if required by
the Trustee, bear a notation in form approved by the Trustee as to any matter
provided for in such supplemental indenture.  If the Company shall so determine,
new Securities so modified as to conform, in the opinion of the Company and the
Trustee, to any such supplemental indenture may be prepared and executed by the
Company and authenticated and delivered by the Trustee in exchange for
Outstanding Securities.

SECTION 8.6    Notice of Supplemental Indentures.
               ---------------------------------

     Promptly after the execution by the Company and the Trustee of any
supplemental indenture pursuant to the provisions of Section 8.2, the Company
                                                     -----------
shall give notice to all Holders of Securities of such fact, setting forth in
general terms the substance of such supplemental indenture in the manner
provided in Section 1.6.  Any failure of the Company to give such notice, or any
            -----------
defect therein, shall not in any way impair or affect the validity of any such
supplemental indenture.

                                    ARTICLE

                                   COVENANTS

SECTION 9.1    Payment of Principal, Premium and Interest.
               ------------------------------------------

     The Company covenants and agrees that it will duly and punctually pay the
principal of and premium, if any (including the Make-Whole Payment, if any), and
interest on the Securities in accordance with the terms of the Securities and
this Indenture.  The Company will deposit or cause to be deposited with the
Trustee, no later than the opening of business on the date of the Stated
Maturity of any Security or no later than the opening of business on the due
date for any installment of interest, all payments so due, which payments shall
be in immediately available funds on the date of such Stated Maturity or due
date, as the case may be.

                                      -59-
<PAGE>

SECTION 9.2    Maintenance of Offices or Agencies.
               ----------------------------------

     The Company hereby appoints the Corporate Trust Office of the Trustee,
where Securities may be presented or surrendered for payment, where Securities
may be surrendered for registration of transfer or exchange, where Securities
may be surrendered for conversion, and where notices and demands to or upon the
Company in respect of the Securities and this Indenture may be served.

     The Company may at any time and from time to time vary or terminate the
appointment of any such agent or appoint any additional agents for any or all of
such purposes; provided, however, that until all of the Securities have been
               --------  -------
delivered to the Trustee for cancellation, or moneys sufficient to pay the
principal of, premium, if any (including the Make-Whole Payment, if any), and
interest on the Securities have been made available for payment and either paid
or returned to the Company pursuant to the provisions of Section 9.3, the
                                                         -----------
Company will maintain in the Borough of Manhattan, The City of New York an
office or agency where Securities may be presented or surrendered for payment
and conversion, where Securities may be surrendered for registration of transfer
or exchange and where notices and demands to or upon the Company in respect of
the Securities and this Indenture may be served.  The Company will give prompt
written notice to the Trustee, and notice to the Holders in accordance with
Section 1.6, of the appointment or termination of any such agents and of the
-----------
location and any change in the location of any such office or agency.

     If at any time the Company shall fail to maintain any such required office
or agency, or shall fail to furnish the Trustee with the address thereof,
presentations and surrenders may be made and notices and demands may be served
on the Corporate Trust Office of the Trustee.

SECTION 9.3    Money for Security Payments To Be Held in Trust.
               -----------------------------------------------

     If the Company shall act as its own Paying Agent, it will, on or before
each due date of the principal of, premium, if any, or interest on any of the
Securities, segregate and hold in trust for the benefit of the Persons entitled
thereto a sum sufficient to pay the principal, premium, if any (including the
Make-Whole Payment, if any), or interest so becoming due until such sums shall
be paid to such Persons or otherwise disposed of as herein provided and the
Company will promptly notify the Trustee of its action or failure so to act.

     Whenever the Company shall have one or more Paying Agents, it will, no
later than the opening of business on each due date of the principal of,
premium, if any (including the Make-Whole Payment, if any), or interest on any
Securities, deposit with the Trustee a sum sufficient to pay the principal,
premium, if any, or interest so becoming due, such sum to be held for the
benefit of the Persons entitled to such principal, premium, if any (including
the Make-Whole Payment, if any), or interest, and (unless such Paying Agent is
the Trustee) the Company will promptly notify the Trustee of any failure so to
act.

                                      -60-
<PAGE>

     The Company will cause each Paying Agent other than the Trustee to execute
and deliver to the Trustee an instrument in which such Paying Agent shall agree
with the Trustee, subject to the provisions of this Section, that such Paying
Agent will:

     (1)  hold all sums held by it for the payment of the principal of, premium,
if any (including the Make-Whole Payment, if any), or interest on Securities for
the benefit of the Persons entitled thereto until such sums shall be paid to
such Persons or otherwise disposed of as herein provided;

     (2)  give the Trustee notice of any default by the Company (or any other
obligor upon the Securities) in the making of any payment of principal, premium,
if any (including the Make-Whole Payment, if any), or interest; and

     (3)  at any time during the continuance of any such default, upon the
written request of the Trustee, forthwith pay to the Trustee all sums so held by
such Paying Agent.

     The Company may at any time, for the purpose of obtaining the satisfaction
and discharge of this Indenture or for any other purpose, pay, or by Company
Order direct any Paying Agent to pay, to the Trustee all sums held in trust by
the Company or such Paying Agent, such sums to be held by the Trustee upon the
same trusts as those upon which such sums were held by the Company or such
Paying Agent; and, upon such payment by any Paying Agent to the Trustee, such
Paying Agent shall be released from all further liability with respect to such
money.

     Any money deposited with the Trustee or any Paying Agent, or then held by
the Company, in trust for the payment of the principal of, premium, if any
(including the Make-Whole Payment, if any), or interest on any Security and
remaining unclaimed for two years after such principal, premium, if any, or
interest has become due and payable shall be paid within 60 days of such date by
the Trustee to the Company on Company Request, as its property free from trust,
or (if then held by the Company) shall be discharged from such trust; and the
Holder of such Security shall thereafter, as an unsecured general creditor, look
only to the Company for payment thereof, and all liability of the Trustee or
such Paying Agent with respect to such trust money, and all liability of the
Company as trustee thereof, shall thereupon cease; provided, however, that the
                                                   --------  -------
Trustee or such Paying Agent, before being required to make any such repayment,
may at the expense of the Company cause to be published once, in an Authorized
Newspaper in each Place of Payment, notice that such money remains unclaimed and
that, after a date specified therein, which shall not be less than 30 days from
the date of such publication, any unclaimed balance of such money then remaining
will be repaid to the Company.

                                      -61-
<PAGE>

SECTION 9.4    Existence.
               ---------

     Subject to Article Seven, the Company will do or cause to be done all
                -------------
things necessary to preserve and keep in full force and effect its existence,
rights (charter and statutory) and franchises; provided, however, that the
                                               --------  -------
Company shall not be required to preserve any such right or franchise if the
Board of Directors shall determine that the preservation thereof is no longer
desirable in the conduct of the business of the Company and that the loss
thereof is not disadvantageous in any material respect to the Holders.

SECTION 9.5    Maintenance of Properties.
               -------------------------

     The Company will cause all properties used or useful in the conduct of its
business or the business of any Significant Subsidiary to be maintained and in
good condition, repair and working order and supplied with all necessary
equipment and will cause to be made all necessary repairs, renewals,
replacements, betterments and improvements thereof, all as in the judgment of
the Company may be necessary so that the business of the Company or such
Significant Subsidiary may be properly and advantageously conducted at all
times; provided, however, that nothing in this Section shall prevent the Company
from discontinuing the operation or maintenance of any of such properties if
such discontinuance is, in the judgment of the Company, desirable in the conduct
of its business or the business of any Significant Subsidiary and not
disadvantageous in any material respects to the Holders.

SECTION 9.6    Payment of Taxes and Other Claims.
               ---------------------------------

     The Company will pay or discharge, or cause to be paid or discharged,
before the same may become delinquent, (1) all taxes, assessments and
governmental charges levied or imposed upon the Company or any Subsidiary or
upon the income, profits or property of the Company or any Subsidiary, and (2)
subject to Sections 11.8 and 13.3(h), all stamps and other duties, if any, which
           -------------     -------
may be imposed by the United States or any political subdivision thereof or
therein in connection with the issuance, transfer, exchange or conversion of any
Securities or with respect to this Indenture; provided, however, that, in the
                                              --------  -------
case of clause (1), the Company shall not be required to pay or discharge or
cause to be paid or discharged any such tax, assessment, charge or claim (a) if
the failure to do so will not, in the aggregate, have a material adverse impact
on the Company, or (b) if the amount, applicability or validity is being
contested in good faith by appropriate proceedings.

SECTION 9.7    Statement by Officers as to Default.
               -----------------------------------

     The Company shall deliver to the Trustee, within 120 days after the end of
each fiscal year of the Company ending after the date hereof, an Officers'
Certificate (one of the signers of which shall be the Company's principal
executive, principal financial or principal accounting officer), stating whether
or not to the best knowledge of the signers thereof the Company is in

                                      -62-
<PAGE>

default in the performance and observance of any of the terms, provisions and
conditions of this Indenture (without regard to any period of grace or
requirement of notice provided hereunder) and, if the Company shall be in
default, specifying all such defaults and the nature and status thereof of which
they may have knowledge.

     The Company will deliver to the Trustee, forthwith upon becoming aware of
any default in the performance or observance of any covenant, agreement or
condition contained in this Indenture, or any Event of Default, an Officers'
Certificate specifying with particularity such default or Event of Default and
further stating what action the Company has taken, is taking or proposes to take
with respect thereto.

     Any notice required to be given under this Section 9.7 shall be delivered
                                                -----------
to the Trustee at its Corporate Trust Office.

SECTION 9.8    Waiver of Certain Covenants.
               ---------------------------

     The Company may omit in any particular instance to comply with any covenant
or conditions set forth in Sections 9.5 to 9.7 or otherwise in this Indenture
(other than a covenant or condition which under Article Eight cannot be modified
                                                -------------
or amended without the consent of the Holder of each Outstanding Security
affected), if before the time for such compliance the Holders shall, through the
written consent of, not less than a majority in principal amount of the
Outstanding Securities, either waive such compliance in such instance or
generally waive compliance with such covenant or condition, but no such waiver
shall extend to or affect such covenant or condition except to the extent so
expressly waived, and, until such waiver shall become effective, the obligations
of the Company and the duties of the Trustee or any Paying or Conversion Agent
in respect of any such covenant or condition shall remain in full force and
effect.

                                    ARTICLE

                           REDEMPTION OF SECURITIES

SECTION 10.1   Right of Redemption.
               -------------------

     The Securities may be redeemed in accordance with the provisions of the
form of Securities set forth in Section 2.2.
                                -----------

SECTION 10.2   Applicability of Article.
               ------------------------

     Redemption of Securities at the election of the Company or otherwise, as
permitted or required by any provision of the Securities or this Indenture,
shall be made in accordance with such provisions and this Article Ten.
                                                          -----------

                                      -63-
<PAGE>

SECTION 10.3   Election to Redeem; Notice to Trustee.
               -------------------------------------

     The election of the Company to redeem any Securities shall be evidenced by
a Board Resolution.  In case of any redemption at the election of the Company of
any of the Securities, the Company shall, at least 60 days prior to the
Redemption Date fixed by the Company (unless a shorter notice shall be
satisfactory to the Trustee), notify the Trustee in writing of such Redemption
Date.

SECTION 10.4   Selection by Trustee of Securities To Be Redeemed.
               -------------------------------------------------

     If less than all the Securities are to be redeemed, the particular
Securities to be redeemed shall be selected by the Trustee within three Business
Days after it receives the notice described in Section 10.3, from the
                                               ------------
Outstanding Securities not previously called for redemption, by such method as
the Trustee may deem fair and appropriate.

     If any Security selected for partial redemption is converted in part before
termination of the conversion right with respect to the portion of the Security
so selected, the converted portion of such Security shall be deemed (so far as
may be) to be the portion selected for redemption.  Securities which have been
converted during a selection of Securities to be redeemed may be treated by the
Trustee as Outstanding for the purpose of such selection.

     The Trustee shall promptly notify the Company and each Security Registrar
in writing of the Securities selected for redemption and, in the case of any
Securities selected for partial redemption, the principal amount and certificate
numbers thereof to be redeemed.

     For all purposes of this Indenture, unless the context otherwise requires,
all provisions relating to the redemption of Securities shall relate, in the
case of any Securities redeemed or to be redeemed only in part, to the portion
of the principal amount of such Securities which has been or is to be redeemed.

SECTION 10.5   Notice of Redemption.
               --------------------

     Notice of redemption shall be given by the Company in the manner provided
in Section 1.6 to the Holders of Securities to be redeemed not less than 30 nor
   -----------
more than 60 days prior to the Redemption Date, and such notice shall be
irrevocable.

     All notices of redemption shall identify the Securities to be redeemed
(including CUSIP numbers) and shall state:

     (1)  the Redemption Date,

     (2)  the Redemption Price, and accrued interest, if any,

                                      -64-
<PAGE>

     (3)  if less than all Outstanding Securities are to be redeemed, the
aggregate principal amount of Securities to be redeemed,

     (4)  that on the Redemption Date the Redemption Price, and accrued
interest, if any, will become due and payable upon each such Security to be
redeemed, and that interest thereon shall cease to accrue on and after said
date,

     (5)  the Conversion Rate, the date on which the right to convert the
Securities to be redeemed will terminate and the places where such Securities
may be surrendered for conversion,

     (6)  the place or places where such Securities are to be surrendered for
payment of the Redemption Price and accrued interest, if any,

     (7)  the CUSIP number printed on the Securities being redeemed,

     (8)  that no representation is made as to the correctness or accuracy of
the CUSIP number, if any, listed in such notice or printed on the Securities,

     (9)  whether the redemption is a Provisional Redemption or an Optional
Redemption,

     (10) if such a redemption is a Provisional Redemption, the amount of the
Make-Whole Payment, and

     (11) whether the Make-Whole Payment will be paid in Common Stock, cash or a
combination of cash and Common Stock.

     Notice of redemption of Securities to be redeemed at the election of the
Company shall be given by the Company or, at the Company's written request, by
the Trustee in the name of and at the expense of the Company.  Notice of
redemption of Securities to be redeemed at the election of the Company received
by the Trustee shall be given by the Trustee to each Paying Agent in the name of
and at the expense of the Company.

SECTION 10.6   Deposit of Redemption Price or Make-Whole Payment.
               -------------------------------------------------

     Not less than one Business Day prior to any Redemption Date, the Company
shall deposit with the Trustee (or, if the Company is acting as its own Paying
Agent, segregate and hold in trust as provided in Section 9.3) (i) an amount of
                                                  -----------
money (which shall be in immediately available funds on such Redemption Date)
sufficient to pay the Redemption Price of, and (except if the Redemption Date
shall be an Interest Payment Date) accrued interest on, all the Securities which
are to be redeemed on that date other than any Securities called for redemption
on that date which have been converted prior to the date of such deposit and
(ii) with respect to Securities called for Provisional Redemption pursuant to
Section 10.1, an amount of money (which shall be

                                      -65-
<PAGE>

in immediately available funds on the Redemption Date) or Common Stock
sufficient to pay the Make-Whole Payment for all the Securities (or portions
thereof) called for redemption (including those surrendered for conversion into
Common Stock after the Notice Date and prior to the Redemption Date in respect
thereof); provided that if such payment is made on the Redemption Date, it must
be received by the Trustee or Paying Agent, as the case may be, by 10:00 a.m.
New York City time on such date.

     If any Security called for redemption is converted, any money deposited
with the Trustee or with any Paying Agent or so segregated and held in trust for
the redemption of such Security shall (subject to any right of the Holder of
such Security or any Predecessor Security to receive interest as provided in the
last paragraph of Section 3.7) be paid to the Company on Company Request or, if
then held by the Company, shall be released from such trust; provided that, with
respect to a Provisional Redemption, any money or Common Stock so deposited for
payment of the Make-Whole Payment shall remain segregated and held in trust for
payment of the Make-Whole Payment which shall be made on all Securities called
for Provisional Redemption, including Securities converted into Common Stock
after the Notice Date and prior to the Redemption Date in respect of such
Provisional Redemption.

SECTION 10.7   Securities Payable on Redemption Date.
               -------------------------------------

     (a)  Notice of redemption having been given as aforesaid, the Securities so
to be redeemed shall, on the Redemption Date, become due and payable at the
Redemption Price therein specified, and, with respect to Securities called for
Provisional Redemption, the Make-Whole Payment, and from and after such date
(unless the Company shall default in the payment of the Redemption Price,
including accrued interest or the Make-Whole Payment, if any) such Securities
shall cease to bear or accrue any interest.  Upon surrender of any such Security
for redemption in accordance with said notice, such Security shall be paid by
the Company at the Redemption Price, together with any accrued and unpaid
interest to (but not including) the Redemption Date and, with respect to
Securities called for Provisional Redemption (including Securities converted
into Common Stock pursuant to the terms hereof after the Notice Date and prior
to the Redemption Date in respect thereof), the Make-Whole Payment; provided,
however, that installments of interest whose Stated Maturity is on or prior to
the Redemption Date shall be payable to the Holders of such Securities, or one
or more Predecessor Securities, registered as such at the close of business on
the relevant Record Dates according to their terms and the provisions of Section
3.7; and provided further that, with respect to a Provisional Redemption, the
holder of any Securities converted into Common Stock pursuant to the terms of
this Indenture after the Notice Date and prior to the Redemption Date in respect
thereof shall have the right to the Make-Whole Payment, if any, with respect to
such Securities regardless of the conversion of such Securities.

     If the Company shall fail to deposit the Redemption Price (and Make-Whole
Payment, if any) with the Trustee and any Security called for redemption shall
not be so paid upon surrender

                                      -66-
<PAGE>

thereof for redemption, the principal and premium, if any (including the Make-
Whole Payment, if any) shall, until paid, bear and accrue interest from the
Redemption Date at the rate borne by the Security.

     (b)  Any issuance of shares of Common Stock in respect of the Make-Whole
Payment shall be deemed to have been effected immediately prior to the close of
business on the Redemption Date and the Person or Persons in whose name or names
any certificate or certificates for shares of Common Stock shall be issuable
upon such repurchase shall be deemed to have become on the Redemption Date the
holder or holders of record of the shares represented thereby.

     (c)  No fractions of shares shall be issued upon Provisional Redemption of
Securities.  If more than one Security shall be so redeemed from the same Holder
and all or any portion of the Make-Whole Payment shall be payable in shares of
Common Stock, the number of full shares which shall be issuable upon such
repurchase shall be computed on the basis of the aggregate principal amount of
the Securities so repurchased. Instead of any fractional share of Common Stock
which would otherwise be issuable on the Provisional Redemption of any Security
or Securities, the Company will deliver to the applicable Holder its check for
the value of such fractional share.  The value of a fraction of a share shall be
determined by multiplying the value of a share of Common Stock for purposes of
the Provisional Redemption by the fraction, and rounding the result to the
nearest cent.

     (d)  Any issuance and delivery of certificates for shares of Common Stock
on Provisional Redemption of Securities shall be made without charge to the
Holder of Securities being redeemed for such certificates or for any tax or duty
in respect of the issuance or delivery of such certificates or the securities
represented thereby; provided, however, that the Company shall not be required
                     --------  -------
to pay any tax or duty which may be payable in respect of (i) income of the
Holder or (ii) any transfer involved in the issuance or delivery of certificates
for shares of Common Stock in a name other than that of the Holder of the
Securities being redeemed, and no such issuance or delivery shall be made unless
and until the Person requesting such issuance or delivery has paid to the
Company the amount of any such tax or duty or has established, to the
satisfaction of the Company, that such tax or duty has been paid.

SECTION 10.8   Securities Redeemed in Part.
               ---------------------------

     Any Security which is to be redeemed only in part shall be surrendered at
an office or agency of the Company designated for that purpose pursuant to
Section 9.2 (with, if the Company or the Trustee so requires, due endorsement
-----------
by, or a written instrument of transfer in form satisfactory to the Trustee duly
executed by, the Holder thereof or his attorney duly authorized in writing), and
the Company shall execute, and the Trustee shall authenticate and make available
for delivery to the Holder of such Security without service charge, a new
Security or Securities, of any authorized denomination as requested by such
Holder, in aggregate principal

                                      -67-
<PAGE>

amount equal to and in exchange for the unredeemed portion of the principal of
the Security so surrendered.  Upon redemption, interests in Global Securities
shall be reduced in accordance with the Applicable Procedures.

SECTION 10.9   Conversion Arrangement on Call for Redemption.
               ---------------------------------------------

     In connection with any redemption of the Securities, the Company may
arrange for the purchase and conversion of any Securities by an agreement with
one or more investment bankers or other purchasers (the "Purchasers") to
purchase such Securities by paying to the Trustee in trust for the Holders, on
or before the Redemption Date, an amount not less than the applicable Redemption
Price, together with any interest accrued and unpaid to the Redemption Date, of
such Securities, and, in connection with a Provisional Redemption, the Make-
Whole Payment.  Notwithstanding anything to the contrary contained in this
Article Ten, the obligation of the Company to pay the Redemption Price, together
-----------
with any interest accrued and unpaid to the Redemption Date, and, in connection
with a Provisional Redemption, the Make-Whole Payment, shall be deemed to be
satisfied and discharged to the extent such amount is so paid by such
Purchasers.  If such an agreement is entered into (a copy of which shall be
filed with the Trustee prior to the close of business on the second Business Day
immediately prior to the Redemption Date), any Securities called for redemption
that are not duly surrendered for conversion by the Holders thereof may, at the
option of the Company, be deemed, to the fullest extent permitted by law, and
consistent with any agreement or agreements with such Purchasers, to be acquired
by such Purchasers from such Holders and (notwithstanding anything to the
contrary contained in this Article Ten) surrendered by such Purchasers for
                           -----------
conversion, all as of immediately prior to the close of business on the
Redemption Date (and the right to convert any such Securities shall be extended
through such time), subject to payment of the above amount as aforesaid,
including the Make-Whole Payment, if any, with respect to all Securities called
for Provisional Redemption.  At the direction of the Company, the Trustee shall
hold and dispose of any such amount paid to it by the Purchasers to the Holders
in the same manner as it would monies deposited with it by the Company for the
redemption of Securities.  Without the Trustee's prior written consent, no
arrangement between the Company and such Purchasers for the purchase and
conversion of any Securities shall increase or otherwise affect any of the
powers, duties, responsibilities or obligations of the Trustee as set forth in
this Indenture, and the Company agrees to indemnify the Trustee from, and hold
it harmless against, any loss, liability or expense arising out of or in
connection with any such arrangement for the purchase and conversion of any
Securities between the Company and such Purchasers, including the costs and
expenses, including reasonable legal fees, incurred by the Trustee in the
defense of any claim or liability arising out of or in connection with the
exercise or performance of any of its powers, duties, responsibilities or
obligations under this Indenture.

                                      -68-
<PAGE>

SECTION 10.10  Conditions to the Company's Election to Pay the Make-Whole
               ----------------------------------------------------------
               Payment in Common Stock.
               -----------------------

     The Company may elect to pay all or a portion of the Make-Whole Payment by
delivery of shares of Common Stock if and only if the following conditions shall
have been satisfied:

     (a)  The shares of Common Stock deliverable in payment of the Make-Whole
Payment shall have a value, as determined in the following sentence, as of the
Repurchase Date of not less than the amount of the Make-Whole Payment.  For
purposes of this Section 10.10, the value of shares of Common Stock shall be
                 -------------
determined by the Company and shall be equal to 95% of the average of the
Closing Price Per Share for the five consecutive Trading Days immediately
preceding and including the third Trading Day prior to the Redemption Date in
respect of such Provisional Redemption;

     (b)  The Make-Whole Payment shall be paid only in cash in the event any
shares of Common Stock to be issued upon redemption of Securities hereunder (i)
require registration under any federal securities law before such shares may be
freely transferable without being subject to any transfer restrictions under the
Securities Act upon redemption and if such registration is not completed or does
not become effective prior to the Redemption Date in respect of such Provisional
Redemption, and/or (ii) require registration with or approval of any
governmental authority under any state law or any other federal law before such
shares may be validly issued or delivered upon repurchase and if such
registration is not completed or does not become effective or such approval is
not obtained prior to the Redemption Date in respect of such Provisional
Redemption;

     (c)  Payment of the Make-Whole Payment may not be made in Common Stock
unless such stock is, or shall have been, approved for quotation on the Nasdaq
National Market or listing or quotation on a national securities exchange or
quotation system, in either case, prior to the Redemption Date in respect of
such Provisional Redemption; and

     (d)  All shares of Common Stock which may be issued upon Provisional
Redemption of Securities will be issued out of the Company's authorized but
unissued Common Stock and, will upon issue, be duly and validly issued and fully
paid and non-assessable and free of any preemptive rights.

     Prior to making all or any portion of a Make-Whole Payment in Common Stock,
the Company shall certify to the Trustee in an Officer's Certificate that all of
the conditions set forth in this Section 10.10 are satisfied in accordance with
                                 -------------
the terms thereof and shall deliver to the Trustee an opinion of counsel to the
Company to the effect that the shares of Common Stock to be issued upon
Provisional Redemption are not subject to any restrictions on transfer under the
Securities Act.

                                      -69-
<PAGE>

                                  ARTICLE XI

                           CONVERSION OF SECURITIES

SECTION 11.1          Conversion Privilege and Conversion Rate.
                      ----------------------------------------

     Subject to and upon compliance with the provisions of this Article, at the
option of the Holder thereof, any Security or any portion of the principal
amount thereof that is U.S.$1,000 or an integral multiple of U.S.$1,000 may be
converted into fully paid and nonassessable shares (calculated as to each
conversion to the nearest 1/100th of a share) of Common Stock of the Company at
the Conversion Rate, determined as hereinafter provided, in effect at the time
of conversion. Such conversion right shall commence upon the original issuance
of the Securities and expire at the close of business on July 1, 2006, subject,
in the case of conversion of any Global Security, to any Applicable Procedures.
In case a Security or portion thereof is called for redemption at the election
of the Company or the Holder thereof exercises his right to require the Company
to repurchase the Security, such conversion right in respect of the Security, or
portion thereof so called, shall expire at the close of business on the Business
Day immediately preceding the Redemption Date or the Repurchase Date, as the
case may be, unless the Company defaults in making the payment due upon
redemption or repurchase, as the case may be (in each case subject as aforesaid
to any Applicable Procedures with respect to any Global Security).

     The rate at which shares of Common Stock shall be delivered upon conversion
(herein called the "Conversion Rate") shall be initially 34.6789 shares of
Common Stock for each U.S.$1,000 principal amount of Securities. The Conversion
Rate shall be adjusted in certain instances as provided in this Article Eleven.
                                                                --------------

SECTION 11.2          Exercise of Conversion Privilege.
                      --------------------------------

     In order to exercise the conversion privilege, the Holder of any Security
to be converted shall surrender such Security, duly endorsed or assigned to the
Company or in blank, at any office or agency of the Company maintained for that
purpose pursuant to Section 9.2, accompanied by a duly signed conversion notice
                    -----------
substantially in the form set forth in Section 2.4 stating that the Holder
                                       -----------
elects to convert such Security or, if less than the entire principal amount
thereof is to be converted, the portion thereof to be converted.  Each Security
surrendered for conversion (in whole or in part) during a Record Date Period
shall (except in the case of any Security or portion thereof which has been
called for redemption or repurchase if the Holder's conversion right would
terminate because of the redemption or repurchase during the Record Date Period)
be accompanied by payment in New York Clearing House funds 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 such Security (or part thereof,
as the case may be) being surrendered for conversion. The interest payable on an
Interest Payment Date with respect to any Security (or portion thereof, if
applicable) which is surrendered for conversion during the Record

                                      -70-
<PAGE>

Date Period corresponding to such Interest Payment Date, shall be paid to the
Holder of such Security as of the Regular Record Date for such Interest Payment
Date in an amount equal to the interest that would have been payable on such
Security if such Security (or a portion thereof) had not been converted.
Interest payable in respect of any Security surrendered for conversion on an
Interest Payment Date shall be paid to the Holder of such Security as of the
next preceding Regular Record Date, notwithstanding the exercise of the right of
conversion. Except as provided in this paragraph and subject to the last
paragraph of Section 3.7, no cash payment or adjustment shall be made upon any
             -----------
conversion on account of any interest accrued from the Interest Payment Date
next preceding the conversion date, in respect of any Security (or part thereof,
as the case may be) surrendered for conversion, or on account of any dividends
on the Common Stock issued upon conversion. The Company's delivery to the Holder
of the number of shares of Common Stock (and cash in lieu of fractions thereof,
as provided in this Indenture) into which a Security is convertible will be
deemed to satisfy the Company's obligation to pay the principal amount of the
Security.

     Securities shall be deemed to have been converted on the day of surrender
of such Securities for conversion in accordance with the foregoing provisions,
and at such time the rights of the Holders of such Securities as Holders shall
cease, and the Person or Persons entitled to receive the Common Stock issuable
upon conversion shall be treated for all purposes as the record holder or
holders of such Common Stock at such time. As promptly as practicable on or
after the conversion date, the Company shall issue and deliver to the Trustee,
for delivery to the Holder (unless a different Person is indicated on the
Conversion Notice), a certificate or certificates for the number of full shares
of Common Stock issuable upon conversion, together with payment in lieu of any
fraction of a share, as provided in Section 11.3.
                                    ------------

     In the case of any Security which is converted in part only, upon such
conversion the Company shall execute and the Trustee shall authenticate and make
available for delivery to the Holder thereof, at the expense of the Company, a
new Security or Securities of authorized denominations in an aggregate principal
amount equal to the unconverted portion of the principal amount of such
Security. A Security may be converted in part, but only if the principal amount
of such Security to be converted is any integral multiple of U.S.$1,000 and the
principal amount of such security to remain Outstanding after such conversion is
equal to U.S.$1,000 or any integral multiple of U.S.$1,000 in excess thereof.

SECTION 11.3          Fractions of Shares.
                      -------------------

     No fractional shares of Common Stock shall be issued upon conversion of any
Security or Securities. If more than one Security shall be surrendered for
conversion at one time by the same Holder, the number of full shares which shall
be issuable upon conversion thereof shall be computed on the basis of the
aggregate principal amount of the Securities (or specified portions thereof) so
surrendered. Instead of any fractional share of Common Stock which would
otherwise be issuable upon conversion of any Security or Securities (or
specified portions

                                      -71-
<PAGE>

thereof), the Company shall calculate and pay a cash adjustment in respect of
such fraction (calculated to the nearest 1/100th of a share) in an amount equal
to the same fraction of the Closing Price Per Share at the close of business on
the day of conversion.

SECTION 11.4          Adjustment of Conversion Rate.
                      -----------------------------

     The Conversion Rate shall be subject to adjustments from time to time as
follows:

     (1)    In case the Company shall pay or make a dividend or other
distribution on any class of capital stock of the Company payable in shares of
Common Stock, the Conversion Rate in effect at the opening of business on the
day following the date fixed for the determination of shareholders entitled to
receive such dividend or other distribution shall be increased by dividing such
Conversion Rate by a fraction of which the numerator shall be the number of
shares of Common Stock outstanding at the close of business on the date fixed
for such determination and the denominator shall be the sum of such number of
shares and the total number of shares constituting such dividend or other
distribution, such increase to become effective immediately after the opening of
business on the day following the date fixed for such determination. If, after
any such date fixed for determination, any dividend or distribution is not in
fact paid, the Conversion Rate shall be immediately readjusted, effective as of
the date the Board of Directors determines not to pay such dividend or
distribution, to the Conversion Rate that would have been in effect if such
determination date had not been fixed. For the purposes of this paragraph (1),
the number of shares of Common Stock at any time outstanding shall not include
shares held in the treasury of the Company but shall include shares issuable in
respect of scrip certificates issued in lieu of fractions of shares of Common
Stock. The Company will not pay any dividend or make any distribution on shares
of Common Stock held in the treasury of the Company.

     (2)    Subject to the last sentence of paragraph (7), in case the Company
shall issue rights, options or warrants to all holders of its Common Stock
entitling them to subscribe for or purchase shares of Common Stock at a price
per share less than the current market price per share (determined as provided
in paragraph (8) of this Section 11.4) of the Common Stock on the date fixed for
                         ------------
the determination of stockholders entitled to receive such rights, options or
warrants (other than any rights, options or warrants that by their terms will
also be issued to any Holder upon conversion of a Security into shares of Common
Stock without any action required by the Company or any other Person), the
Conversion Rate in effect at the opening of business on the day following the
date fixed for such determination shall be increased by dividing such Conversion
Rate by a fraction of which the numerator shall be the number of shares of
Common Stock outstanding at the close of business on the date fixed for such
determination plus the number of shares of Common Stock which the aggregate of
the offering price of the total number of shares of Common Stock so offered for
subscription or purchase would purchase at such current market price and the
denominator shall be the number of shares of Common Stock outstanding at the
close of business on the date fixed for such determination plus the number of
shares of Common Stock so offered for subscription or purchase, such increase to
become

                                      -72-
<PAGE>

effective immediately after the opening of business on the day following the
date fixed for such determination. If, after any such date fixed for
determination, any such rights, options or warrants are not in fact issued, the
Conversion Rate shall be immediately readjusted, effective as of the date the
Board of Directors determines not to issue such rights, options or warrants, to
the Conversion Rate that would have been in effect if such determination date
had not been fixed. For the purposes of this paragraph (2), the number of shares
of Common Stock at any time outstanding shall not include shares held in the
treasury of the Company but shall include shares issuable in respect of scrip
certificates issued in lieu of fractions of shares of Common Stock. The Company
will not issue any rights, options or warrants in respect of shares of Common
Stock held in the treasury of the Company.

     (3)    In case outstanding shares of Common Stock shall be subdivided into
a greater number of shares of Common Stock, the Conversion Rate in effect at the
opening of business on the day following the day upon which such subdivision
becomes effective shall be proportionately increased, and, conversely, in case
outstanding shares of Common Stock shall each be combined into a smaller number
of shares of Common Stock, the Conversion Rate in effect at the opening of
business on the day following the day upon which such combination becomes
effective shall be proportionately reduced, such increase or reduction, as the
case may be, to become effective immediately after the opening of business on
the day following the day upon which such subdivision or combination becomes
effective.

     (4)    Subject to the last sentence of paragraph (7), in case the Company
shall, by dividend or otherwise, distribute to all holders of its Common Stock
evidences of its indebtedness, shares of any class of capital stock, or rights,
options or warrants to subscribe for or purchase shares of any class of capital
stock (other than any rights, options or warrants that by their terms will also
be issued to any Holder upon conversion of a Security into shares of Common
Stock without any action required by the Company or any other Person) or other
property (including cash or assets or securities, but excluding (i) any rights,
options or warrants referred to in paragraph (2) of this Section, (ii) any
dividend or distribution paid exclusively in cash, (iii) any dividend or
distribution referred to in paragraph (1) of this Section and (iv) any
consideration distributed in any merger or consolidation to which Section 11.11
                                                                  -------------
applies), the Conversion Rate shall be adjusted so that the same shall equal the
rate determined by dividing the Conversion Rate in effect immediately prior to
the close of business on the date fixed for the determination of stockholders
entitled to receive such distribution by a fraction of which the numerator shall
be the current market price per share (determined as provided in paragraph (8)
of this Section 11.4) of the Common Stock on the date fixed for such
        -------------
determination less the then fair market value (as determined by the Board of
Directors, whose determination shall be conclusive and described in a Board
Resolution filed with the Trustee) of the portion of the assets, shares or
evidences of indebtedness or rights, options or warrants so distributed
applicable to one share of Common Stock and the denominator shall be such
current market price per share of the Common Stock, such adjustment to become
effective immediately prior to the opening of business on the day following the
date fixed for the determination of stockholders entitled to

                                      -73-
<PAGE>

receive such distribution. If, after any such date fixed for determination, any
such distribution is not in fact made, the Conversion Rate shall be immediately
readjusted, effective as of the date the Board of Directors determines not to
make such distribution, to the Conversion Rate that would have been in effect if
such determination date had not been fixed.

     (5)    In case the Company shall, by dividend or otherwise, distribute to
all holders of its Common Stock cash (excluding any cash that is distributed
upon a merger or consolidation to which Section 11.11 applies or as part of a
                                        -------------
distribution referred to in paragraph (4) of this Section) in an aggregate
amount that, combined together with (I) the aggregate amount of any other cash
distributions to all holders of its Common Stock made exclusively in cash within
the 12 months preceding the date of payment of such distribution and in respect
of which no adjustment pursuant to this paragraph (5) has been made and (II) the
aggregate of any cash plus the fair market value (as determined by the Board of
Directors, whose determination shall be conclusive and described in a Board
Resolution) of other  consideration payable in respect of any tender offer by
the Company or any of its subsidiaries for all or any portion of the Common
Stock concluded within the 12 months preceding the date of payment of such
distribution and in respect of which no adjustment pursuant to paragraph (6) of
this Section 11.4 has been made (the "combined cash and tender amount") exceeds
     ------------
10% of the product of the current market price per share (determined as provided
in paragraph (8) of this Section 11.4) of the Common Stock on the date for the
                         ------------
determination of holders of shares of Common Stock entitled to receive such
distribution times the number of shares of Common Stock outstanding on such date
(the "threshold amount"), then, and in each such case, immediately after the
close of business on such date for determination, the Conversion Rate shall be
adjusted so that the same shall equal the rate determined by dividing the
Conversion Rate in effect immediately prior to the close of business on the date
fixed for determination of the stockholders entitled to receive such
distribution by a fraction (i) the numerator of which shall be equal to the
current market price per share (determined as provided in paragraph (8) of this
Section) of the Common Stock on the date fixed for such determination less an
amount equal to the quotient of (x) the excess of such combined cash and tender
amount over such threshold amount divided by (y) the number of shares of Common
Stock outstanding on such date for determination and (ii) the denominator of
which shall be equal to the current market price per share (determined as
provided in paragraph (8) of this Section 11.4) of the Common Stock on such date
                                  ------------
for determination.

     (6)    In case a tender offer made by the Company or any Subsidiary for all
or any portion of the Common Stock shall expire and such tender offer (as
amended upon the expiration thereof) shall require the payment to stockholders
(based on the acceptance (up to any maximum specified in the terms of the tender
offer) of Purchased Shares (as defined below)) of an aggregate consideration
having a fair market value (as determined by the Board of Directors, whose
determination shall be conclusive and described in a Board Resolution) that
combined together with (I) the aggregate of the cash plus the fair market value
(as determined by the Board of Directors, whose determination shall be
conclusive and described in a Board Resolution), as of the expiration of such
tender offer, of consideration payable in respect of any other tender offer

                                      -74-
<PAGE>

by the Company or any Subsidiary for all or any portion of the Common Stock
expiring within the 12 months preceding the expiration of such tender offer and
in respect of which no adjustment pursuant to this paragraph (6) has been made
and (II) the aggregate amount of any cash distributions to all holders of the
Company's Common Stock within 12 months preceding the expiration of such tender
offer and in respect of which no adjustment pursuant to paragraph (5) of this
Section has been made (the "combined tender and cash amount") exceeds 10% of the
product of the current market price per share of the Common Stock (determined as
provided in paragraph (8) of this Section 11.4) as of the last time (the
                                  ------------
"Expiration Time") tenders could have been made pursuant to such tender offer
(as it may be amended) times the number of shares of Common Stock outstanding
(including any tendered shares) as of the Expiration Time, then, and in each
such case, immediately prior to the opening of business on the day after the
date of the Expiration Time, the Conversion Rate shall be adjusted so that the
same shall equal the rate determined by dividing the Conversion Rate immediately
prior to close of business on the date of the Expiration Time by a fraction (i)
the numerator of which shall be equal to (A) the product of (I) the current
market price per share of the Common Stock (determined as provided in paragraph
(8) of this Section 11.4) on the date of the Expiration Time multiplied by (II)
            ------------
the number of shares of Common Stock outstanding (including any tendered shares)
on the Expiration Time less (B) the combined tender and cash amount, and (ii)
the denominator of which shall be equal to the product of (A) the current market
price per share of the Common Stock (determined as provided in paragraph (8) of
this Section 11.4) as of the Expiration Time multiplied by (B) the number of
     ------------
shares of Common Stock outstanding (including any tendered shares) as of the
Expiration Time less the number of all shares validly tendered and not withdrawn
as of the Expiration Time (the shares deemed so accepted up to any such maximum,
being referred to as the "Purchased Shares").

     (7)    The reclassification of Common Stock into securities other than
Common Stock (other than any reclassification upon a consolidation or merger to
which Section 11.11 applies) shall be deemed to involve (a) a distribution of
      -------------
such securities other than Common Stock to all holders of Common Stock (and the
effective date of such reclassification shall be deemed to be "the date fixed
for the determination of stockholders entitled to receive such distribution" and
"the date fixed for such determination" within the meaning of paragraph (4) of
this Section), and (b) a subdivision or combination, as the case may be, of the
number of shares of Common Stock outstanding immediately prior to such
reclassification into the number of shares of Common Stock outstanding
immediately thereafter (and the effective date of such reclassification shall be
deemed to be "the day upon which such subdivision becomes effective" or "the day
upon which such combination becomes effective," as the case may be, and "the day
upon which such subdivision or combination becomes effective" within the meaning
of paragraph (3) of this Section 11.4). Rights, options or warrants issued by
                         ------------
the Company to all holders of its Common Stock entitling the holders thereof to
subscribe for or purchase shares of capital stock of the Company, which rights,
options or warrants (i) are deemed to be transferred with such shares of Common
Stock, (ii) are not exercisable and (iii) are also issued in respect of future
issuances of shares of capital stock, in each case in clauses (i) through (iii)
until the occurrence of a specified

                                      -75-
<PAGE>

event or events ("Trigger Event"), shall for purposes of this Section 11.4 not
                                                              ------------
be deemed issued or distributed until the occurrence of the earliest Trigger
Event.

     (8)    For the purpose of any computation under paragraphs (2), (4), (5) or
(6) of this Section 11.4, the current market price per share of Common Stock on
            ------------
any date shall be calculated by the Company and be deemed to be the average of
the daily Closing Prices Per Share for the five consecutive Trading Days
selected by the Company commencing not more than 10 Trading Days before, and
ending not later than, the earlier of the day in question and the day before the
"ex date" with respect to the issuance or distribution requiring such
computation. For purposes of this paragraph, the term "ex date," when used with
respect to any issuance or distribution, means the first date on which the
Common Stock trades regular way in the applicable securities market or on the
applicable securities exchange without the right to receive such issuance or
distribution.

     (9)    No adjustment in the Conversion Rate shall be required unless such
adjustment (plus any adjustments not previously made by reason of this paragraph
(9)) would require an increase or decrease of at least one percent in such rate;
provided, however, that any adjustments which by reason of this paragraph (9)
--------  -------
are not required to be made shall be carried forward and taken into account in
any subsequent adjustment. All calculations under this Article shall be made to
the nearest cent or to the nearest one-hundredth of a share, as the case may be.

     (10)   The Company may make such increases in the Conversion Rate, for the
remaining term of the Securities or any shorter term, in addition to those
required by paragraphs (1), (2), (3), (4), (5) and (6) of this Section 11.4, as
                                                               ------------
it considers to be advisable in order to avoid or diminish any income tax
liability to any holders of shares of Common Stock resulting from any dividend
or distribution of Common Stock or issuance of rights or warrants to purchase or
subscribe for Common Stock or from any event treated as such for income tax
purposes.

     To the extent permitted by applicable law, the Company from time to time
may increase the Conversion Rate by any amount for any period of time if the
period is at least twenty (20) days and the Board of Directors shall have made a
determination that such increase would be in the best interests of the Company,
which determination shall be conclusive; provided, however, that such increase
                                         --------  -------
shall not be taken into account for purposes of determining whether the Closing
Price Per Share of the Common Stock exceeds the Conversion Price by 105% in
connection with an event which would otherwise be a Change in Control. Whenever
the Conversion Rate is increased pursuant to the preceding sentence, the Company
shall give notice of the increase to the Holders of Securities in the manner
provided in Section 1.6 at least fifteen (15) days prior to the date the
increased Conversion Rate takes effect, and such notice shall state the
increased Conversion Rate and the period during which it will be in effect. The
"Conversion Price" shall equal U.S.$1,000 divided by the Conversion Rate
(rounded to the nearest cent).

                                      -76-
<PAGE>

     (11)   Notwithstanding the foregoing provisions of this Section, no
adjustment of the Conversion Rate shall be required to be made (a) upon the
issuance of shares of Common Stock pursuant to any present or future plan for
the reinvestment of dividends or (b) because of a tender or exchange offer of
the character described in Rule 13e-4(h)(5) under the Exchange Act or any
successor rule thereto.

SECTION 11.5     Notice of Adjustments of Conversion Rate.
                 ----------------------------------------

     Whenever the Conversion Rate is adjusted as herein provided:

     (1)    the Company shall compute the adjusted Conversion Rate in accordance
with Section 11.4 and shall prepare a certificate signed by the Chief Financial
     ------------
Officer of the Company setting forth the adjusted Conversion Rate and showing in
reasonable detail the facts upon which such adjustment is based, and such
certificate shall promptly be filed with the Trustee and with each Conversion
Agent; and

     (2)    upon each such adjustment, a notice stating that the Conversion Rate
has been adjusted and setting forth the adjusted Conversion Rate shall be
required, and as soon as practicable after it is required, such notice shall be
provided by the Company to all Holders in accordance with Section 1.6.
                                                          -----------

Neither the Trustee nor any Conversion Agent shall be under any duty or
responsibility with respect to any such certificate or the information and
calculations contained therein, except to exhibit the same to any Holder of
Securities desiring inspection thereof at its office during normal business
hours.

SECTION 11.6     Notice of Certain Corporate Action.
                 ----------------------------------


     In case:

     (a)    the Company shall declare a dividend (or any other distribution) on
its Common Stock payable (i) otherwise than exclusively in cash or (ii)
exclusively in cash in an amount that would require any adjustment pursuant to
Section 11.4; or
------------

     (b)    the Company shall authorize the granting to the holders of its
Common Stock of rights, options or warrants to subscribe for or purchase any
shares of capital stock of any class or of any other rights (other than rights,
options or warrants described in the last sentence of Section 11.4(7); or
                                                      ---------------

     (c)    of any reclassification of the Common Stock of the Company, or of
any consolidation, merger or share exchange to which the Company is a party and
for which approval

                                      -77-
<PAGE>

of any stockholders of the Company is required, or of the conveyance, sale,
transfer or lease of all or substantially all of the assets of the Company; or

     (d)    of the voluntary or involuntary dissolution, liquidation or winding
up of the Company;

then the Company shall cause to be filed at each office or agency maintained for
the purpose of conversion of Securities pursuant to Section 9.2, and shall cause
                                                    -----------
to be provided to all Holders in accordance with Section 1.6, at least 20 days
                                                 -----------
(or 10 days in any case specified in clause (a) or (b) above) prior to the
applicable record or effective date hereinafter specified, a notice stating (x)
the date on which a record is to be taken for the purpose of such dividend,
distribution, rights, options or warrants, or, if a record is not to be taken,
the date as of which the holders of Common Stock of record to be entitled to
such dividend, distribution, rights, options or warrants are to be determined or
(y) the date on which such reclassification, consolidation, merger, conveyance,
transfer, sale, lease, 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, cash or other property deliverable upon such reclassification,
consolidation, merger, conveyance, transfer, sale, lease, dissolution,
liquidation or winding up. Neither the failure to give such notice or the notice
referred to in the following paragraph nor any defect therein shall affect the
legality or validity of the proceedings described in clauses (a) through (d) of
this Section 11.6.  If at the time the Trustee shall not be the Conversion
     ------------
Agent, a copy of such notice shall also forthwith be filed by the Company with
the Trustee.

     The Company shall cause to be filed at each office or agency maintained for
the purpose of conversion of Securities pursuant to Section 9.2, and shall cause
                                                    -----------
to be provided to all Holders in accordance with Section 1.6, notice of any
                                                 -----------
tender offer by the Company or any Subsidiary for all or any portion of the
Common Stock at or about the time that such notice of tender offer is provided
to the public generally.

SECTION 11.7          Company to Reserve Common Stock.
                      -------------------------------

     The Company shall at all times reserve and keep available, free from
preemptive rights, out of its authorized but unissued Common Stock, for the
purpose of effecting the conversion of Securities, the full number of shares of
Common Stock then issuable upon the conversion of all Outstanding Securities.

SECTION 11.8          Taxes on Conversions.
                      --------------------

     Except as provided in the next sentence, the Company will pay any and all
taxes and duties that may be payable in respect of the issue or delivery of
shares of Common Stock on conversion of Securities pursuant hereto. The Company
shall not, however, be required to pay

                                      -78-
<PAGE>

any tax or duty which may be payable in respect of (i) income of the Holder or
(ii) any transfer involved in the issue and delivery of shares of Common Stock
in a name other than that of the Holder of the Security or Securities to be
converted, and no such issue or delivery shall be made unless and until the
Person requesting such issue has paid to the Company the amount of any such tax
or duty, or has established to the satisfaction of the Company that such tax or
duty has been paid.

SECTION 11.9          Covenant as to Common Stock.
                      ---------------------------

     The Company agrees that all shares of Common Stock which may be delivered
upon conversion of Securities, upon such delivery, will have been duly
authorized and validly issued and will be fully paid and nonassessable and,
except as provided in Section 11.8, the Company will pay all taxes, liens and
                      ------------
charges with respect to the issue thereof.

SECTION 11.10         Cancellation of Converted Securities.
                      ------------------------------------

     All Securities delivered for conversion shall be delivered to the Trustee
or its agent to be canceled by or at the direction of the Trustee, which shall
dispose of the same as provided in Section 3.9.
                                   -----------

SECTION 11.11         Provision in Case of Consolidation, Merger or Sale of
                      -----------------------------------------------------
                      Assets.
                      ------


     In case of any consolidation or merger of the Company with or into any
other Person, any merger of another Person with or into the Company (other than
a merger which does not result in any reclassification, conversion, exchange or
cancellation of outstanding shares of Common Stock of the Company) or any
conveyance, sale, transfer or lease of all or substantially all of the assets of
the Company, the Person formed by such consolidation or resulting from such
merger or which acquires such assets, as the case may be, shall execute and
deliver to the Trustee a supplemental indenture providing that the Holder of
which Security then Outstanding shall have the right thereafter, during the
period such Security shall be convertible as specified in the Section 11.1, to
                                                              ------------
convert such Security only into the kind and amount of securities, cash and
other property receivable upon such consolidation, merger, conveyance, sale,
transfer, or lease assuming such holder of Common Stock of the Company (i) is
not a Person with which the Company consolidated or merged with or into or
which merged into or with the Company or to which such conveyance, sale,
transfer or lease was made, as the case may be ("Constituent Person"), or an
Affiliate of a Constituent Person and (ii) failed to exercise his rights of
election, if any, as to the kind or amount of securities, cash and other
property receivable upon such consolidation, merger, conveyance, sale, transfer
or lease (provided that if the kind or amount of securities, cash and other
          --------
property receivable upon such consolidation, merger, conveyance, sale, transfer,
or lease is not the same for each share of Common Stock of

                                      -79-
<PAGE>

the Company held immediately prior to such consolidation, merger, conveyance,
sale, transfer or lease by others than a Constituent Person or an Affiliate
thereof and in respect of which such rights of election shall not have been
exercised ("Non-electing Share"), then for the purpose of this Section 11.11 the
                                                               -------------
kind and amount of securities, cash and other property receivable upon such
consolidation, merger, conveyance, sale, transfer or lease by the holders of
each Non-electing Share shall be deemed to be the kind and amount so receivable
per share by a plurality of the Non-electing Shares). Such supplemental
indenture shall provide for adjustments which, for events subsequent to the
effective date of such supplemental indenture, shall be as nearly equivalent as
may be practicable to the adjustments provided for in this Article. The above
provisions of this Section 11.11 shall similarly apply to successive
                   -------------
consolidations, mergers, conveyances, sales, transfers or leases. Notice of the
execution of such a supplemental indenture shall be given by the Company to the
Holder of each Security as provided in Section 1.6 promptly upon such execution.
                                       -----------

     Neither the Trustee nor any Conversion Agent shall be under any
responsibility to determine the correctness of any provisions contained in any
such supplemental indenture relating either to the kind or amount of shares of
stock or other securities or property or cash receivable by Holders of
Securities upon the conversion of their Securities after any such consolidation,
merger, conveyance, transfer, sale or lease or to any such adjustment, but may
accept as conclusive evidence of the correctness of any such provisions, and
shall be protected in relying upon, an Opinion of Counsel with respect thereto,
which the Company shall cause to be furnished to the Trustee upon request.


SECTION 11.2          Responsibility of Trustee for Conversion Provisions.
                      ---------------------------------------------------

     The Trustee, subject to the provisions of Section 6.1 and any Conversion
                                               -----------
Agent shall not at any time be under any duty or responsibility to any Holder of
Securities to determine whether any facts exist which may require any adjustment
of the Conversion Rate, or with respect to the nature or extent of any such
adjustment when made, or with respect to the method employed, or herein or in
any supplemental indenture provided to be employed, in making the same, or
whether a supplemental indenture need be entered into or to recalculate or
verify the content of any certificate filed with it by the Company pursuant to
the terms of this Article Eleven. Neither the Trustee, subject to the provisions
of Section 6.1, nor any Conversion Agent shall be accountable with respect to
   -----------
the validity or value (or the kind or amount) of any Common Stock, or of any
other securities or property or cash, which may at any time be issued or
delivered upon the conversion of any Security; and it or they do not make any
representation with respect thereto. Neither the Trustee, subject to the
provisions of Section 6.1, nor any Conversion Agent shall be responsible for any
failure of the Company to make or calculate any cash payment or to issue,
transfer or deliver any shares of Common Stock or share certificates or other
securities or property or cash upon the surrender of any Security for the
purpose of conversion; and the Trustee, subject to the provisions of Section
                                                                     -------
6.1, and any Conversion Agent shall not be
---

                                      -80-
<PAGE>

responsible for any failure of the Company to comply with any of the covenants
of the Company contained in this Article.

                                  ARTICLE XII

                          SUBORDINATION OF SECURITIES

SECTION 12.1          Securities Subordinate to Senior Debt.
                      -------------------------------------

     The Company covenants and agrees, and each Holder of a Security, by its
acceptance thereof, likewise covenants and agrees, that, to the extent and in
the manner hereinafter set forth in this Article (subject to the provisions of
Article Four), the indebtedness represented by the Securities and the payment of
------------
the principal of (and premium, if any) and interest on and any payment of the
Repurchase Price with respect to, each and all of the Securities are hereby
expressly made subordinate and subject in right of payment to the prior payment
in full of all Senior Debt.

SECTION 12.2          No Payments in Certain Circumstances; Payment Over of
                      -----------------------------------------------------
                      Proceeds Upon Dissolution, Etc.
                      ------------------------------

     No payment on account of principal of, premium, if any, or interest on, or
redemption or repurchase of, the Securities shall be made if either of the
following occurs:  (i) the Company defaults in its obligation to pay principal,
premium, if any (including the Make-Whole Payment, if any), or interest or other
amounts on its Senior Debt, including default under any redemption or repurchase
obligation, and the default continues beyond any grace period that the Company
may have to make those payments, unless and until such default shall have been
cured or waived, or shall have ceased to exist, or (ii) any other default occurs
and is continuing on any Designated Senior Debt and (1) the default permits the
holders of the Designated Senior Debt to accelerate its maturity and (2) the
Trustee has received a notice of the default (a "Payment Blockage Notice") from
the Company or any other Person permitted to give such notice pursuant to
Sections 12.5 and 12.6 hereof.
-------------     ----

     Notwithstanding the foregoing, the Company may make, and the Trustee may
receive and shall apply, any payment in respect of the Securities (for
principal, premium, if any, interest, or repurchase) if such payment was made
prior to the occurrence of any of the contingencies specified in clauses (i) and
(ii) above.

     If the Trustee receives any Payment Blockage Notice pursuant to clause (ii)
above, no subsequent Payment Blockage Notice shall be effective for purposes of
this Section unless and until (A) at least 365 days shall have elapsed since the
effectiveness of the immediately prior Payment Blockage Notice, and (B) all
scheduled payments of principal, premium, if any (including the Make-Whole
Payment, if any), and interest on the Securities that have come due

                                      -81-
<PAGE>

have been paid in full. No default, other than a payment default, that existed
or was continuing on the date of delivery of any Payment Blockage Notice to the
Trustee shall be, or be made, the basis for a subsequent Payment Blockage
Notice.

     The Company may and shall resume payments on and distributions in respect
of the Securities upon the earlier of: (i) the date upon which the default is
cured or waived, or (ii) in the case of a default referred to in clause (ii) of
the third preceding paragraph, 179 days pass after notice is received if the
maturity of such Designated Senior Debt has not been accelerated, unless this
Article otherwise prohibits the payment or distribution at the time of such
payment or distribution.

     Upon (i) any acceleration of the principal amount due on the Securities or
(ii) any payment or distribution of assets of the Company of any kind or
character, whether in cash, property or securities, to creditors upon any
dissolution, winding up or total or partial liquidation or reorganization of the
Company, whether voluntary or involuntary, or in bankruptcy, insolvency,
receivership or other proceedings, all principal of, premium, if any, sinking
fund and interest or other amounts due or to become due upon all Senior Debt
shall first be paid in full, or payment thereof provided for in money or money's
worth in accordance with its terms, before any payment is made on account of the
principal of, premium, if any (including the Make-Whole Payment, if any), or
interest on, or repurchase of, the indebtedness evidenced by the Securities or
any coupon appertaining thereto, and upon any such dissolution or winding up or
liquidation or reorganization any payment or distribution of assets of the
Company of any kind or character, whether in cash, property or securities, to
which the Holders of the Securities or any coupons appertaining thereto or the
Trustee under this Indenture would be entitled, except for the provisions
hereof, shall be paid by the Company or by any receiver, trustee in bankruptcy,
liquidating trustee, agent or other Person making such payment or distribution,
or by the Holders of the Securities or any coupons appertaining thereto or by
the Trustee under this Indenture if received by them or it, as the case may be,
directly to the holders of Senior Debt (pro rata to each such holder on the
basis of the respective amounts of Senior Debt held by such Holder) or their
representatives, to the extent necessary to pay all Senior Debt in full, in
money or money's worth, after giving effect to any concurrent payment or
distribution to or for the holders of Senior Debt, before any payment or
distribution is made to the Holders of the Securities or any coupons
appertaining thereto or to the Trustee under this Indenture.

     In the event that, contrary to the foregoing, any payment or distribution
of assets of the Company of any kind or character, whether in cash, property or
securities, other than junior securities described in Section 12.11, shall be
received by the Trustee or the Holders of the Securities before all Senior Debt
is paid in full or provision made for such payment, in accordance with its
terms, such payment or distribution shall be paid over or delivered to, the
holders of such Senior Debt or their representative or representatives, or to
the trustee or trustees under any indenture pursuant to which any instruments
evidencing any of such Senior Debt have been issued, as their respective
interests may appear, for application to the payment of all Senior

                                      -82-
<PAGE>

Debt remaining unpaid to the extent necessary to pay all such Senior Debt in
full in accordance with its terms, after giving effect to any concurrent payment
or distribution to or for the holders of such Senior Debt.

     Subject to the payment in full of all Senior Debt, the Holders of the
Securities and any coupons (together with the holders of any other indebtedness
of the Company which is subordinated in right of payment to the payment in full
of all Senior Debt, but which is not subordinated in right of payment to the
Securities and which by its terms grants such right of subrogation to the
holders thereof) shall be subrogated to the rights of the holders of Senior Debt
to receive payments or distribution of assets of the Company made on the Senior
Debt until the principal of, premium, if any (including the Make-Whole Payment,
if any), and interest on, or amounts payable upon repurchase of, the Securities
shall be paid in full; and, for the purposes of such subrogation, no payments or
distributions to the holders of Senior Debt of any cash, property or securities
to which the Holders of the Securities and any coupons appertaining thereto or
the Trustee would be entitled except for the provisions of this Article, and no
payment over pursuant to the provisions of this Article to the holders of Senior
Debt by the Holders of the Securities or any coupon or the Trustee, shall, as
between the Company, its creditors other than the holders of Senior Debt, and
the Holders of Securities and coupons, be deemed to be a payment by the Company
to the holders of or on account of Senior Debt, it being understood that the
provisions of this Article are and are intended solely for the purpose of
defining the relative rights of the Holders of the Securities and coupons, on
the one hand, and the holders of Senior Debt, on the other hand.


SECTION 12.3          Trustee to Effectuate Subordination.
                      -----------------------------------

     Each holder of a Security by his acceptance thereof authorizes and directs
the Trustee on his behalf to take such action as may be necessary or appropriate
to effectuate the subordination provided in this Article and appoints the
Trustee his attorney-in-fact for any and all such purposes.

SECTION 12.4          No Waiver of Subordination Provisions.
                      -------------------------------------

     No right of any present or future holder of any Senior Debt to enforce
subordination as herein provided shall at any time in any way be prejudiced or
impaired by any act or failure to act on the part of the Company or by any act
or failure to act, in good faith, by any such holder of any Senior Debt, or by
any non-compliance by the Company with the terms, provisions and covenants of
this Indenture, regardless of any knowledge thereof any such holder may have or
be otherwise charged with.

     Without in any way limiting the generality of the foregoing paragraph, the
holders of Senior Debt may, at any time and from time to time, without the
consent of or notice to the Trustee or the Holders of the Securities, without
incurring responsibility to the Holders of the

                                      -83-
<PAGE>

Securities and without impairing or releasing the subordination provided in this
Article or the obligations hereunder of the Holders of the Securities to the
holders of Senior Debt, do any one or more of the following: (i) change the
manner, place or terms of payment or extend the time of payment of, or renew or
alter, Senior Debt, or otherwise amend or supplement in any manner Senior Debt
or any instrument evidencing the same or any agreement under which Senior Debt
is outstanding; (ii) sell, exchange, release or otherwise deal with any property
pledged, mortgaged or otherwise securing Senior Debt; (iii) release any Person
liable in any manner for the collection of Senior Debt; and (iv) exercise or
refrain from exercising any rights against the Company and any other Person.

SECTION 12.5          Notice to Trustee.
                      -----------------

     The Company shall give prompt written notice to the Trustee of any fact
known to the Company which would prohibit the making of any payment to or by the
Trustee in respect of the Securities. Notwithstanding the provisions of this
Article or any other provision of this Indenture, the Trustee shall not be
charged with knowledge of the existence of any facts which would prohibit the
making of any payment to or by the Trustee in respect of the Securities, unless
and until the Trustee shall have received written notice thereof from the
Company or a holder of Senior Debt or from any trustee, agent or representative
therefor; and, prior to the receipt of any such written notice, the Trustee,
subject to the provisions of Section 6.1, shall be entitled in all respects to
                             -----------
assume that no such facts exist; provided, however, that if the Trustee shall
                                 --------  -------
not have received the notice provided for in this Section 12.5 prior to the date
                                                  ------------
upon which by the terms hereof any money may become payable for any purpose
(including, without limitation, the payment of the principal of, premium, if any
(including the Make-Whole Payment, if any) or interest on any Security, then,
anything herein contained to the contrary notwithstanding the Trustee shall have
full power and authority to receive such money and to apply the same to the
purpose for which such money was received and shall not be affected by any
notice to the contrary which may be received by it within two Business Days
prior to such date or after such date.

     Subject to the provisions of Section 6.1, the Trustee shall be entitled to
                                  -----------
rely on the delivery to it of a written notice by a Person representing himself
to be a holder of Senior Debt (or a trustee, agent or representative therefor)
to establish that such notice has been given by a holder of Senior Debt (or a
trustee, agent or representative therefor). In the event that the Trustee
determines in good faith that further evidence is required with respect to the
right of any Person as a holder of Senior Debt to participate in any payment or
distribution pursuant to this Article, the Trustee may request such Person to
furnish evidence to the reasonable satisfaction of the Trustee as to the amount
of Senior Debt held by such Person, the extent to which such Person is entitled
to participate in such payment or distribution and any other facts pertinent to
the rights of such Person under this Article, and if such evidence is not
furnished, the Trustee may defer any payment to such Person pending judicial
determination as to the right of such Person to receive

                                      -84-
<PAGE>

such payment, and during such deferral to also defer application of said payment
for which such money was received pursuant to this Indenture.

SECTION 12.6  Reliance on Judicial Order or Certificate of Liquidating
              --------------------------------------------------------
              Agent.
              -----

     Upon any payment or distribution of assets of the Company referred to in
this Article, the Trustee, subject to the provisions of Section 6.1, and the
                                                        -----------
Holders of the Securities shall be entitled to rely upon any order or decree
entered by any court of competent jurisdiction in which such insolvency,
bankruptcy, receivership, liquidation, reorganization, dissolution, winding up
or similar case or proceeding is pending, or a certificate of the trustee in
bankruptcy, receiver, liquidating trustee, custodian, assignee for the benefit
of creditors, agent or other Person making such payment or distribution,
delivered to the Trustee or to the Holders of Securities, for the purpose of
ascertaining the Persons entitled to participate in such payment or
distribution, the holders of the Senior Debt and other indebtedness of the
Company, the amount thereof or payable thereon, the amount or amounts paid or
distributed thereon and all other facts pertinent thereto or to this Article.

SECTION 12.7  Trustee Not Fiduciary for Holders of Senior Debt.
              ------------------------------------------------

     The Trustee shall not be deemed to owe any fiduciary duty to the holders of
Senior Debt and shall not be liable to any such holders if it shall in good
faith mistakenly pay over or distribute to Holders of Securities or to the
Company or to any other Person cash, property or securities to which any holders
of Senior Debt shall be entitled by virtue of this Article or otherwise. With
respect to the holders of Senior Debt, the Trustee undertakes to perform or to
observe only such of its covenants or obligations as are specifically set forth
in this Article Twelve, and no implied covenants or obligations with respect to
        --------------
holders of Senior Debt shall be read into this Indenture against the Trustee.

SECTION 12.8  Reliance by Holders of Senior Debt on Subordination
              ---------------------------------------------------
              Provisions.
              ----------

     Each Holder by accepting a Security acknowledges and agrees that the
foregoing subordination provisions are, and are intended to be, an inducement
and a consideration to each holder of any Senior Debt, whether such Senior Debt
was created or acquired before or after the issuance of the Securities, to
acquire and continue to hold, or to continue to hold, such Senior Debt and such
holder of Senior Debt shall be deemed conclusively to have relied on such
subordination provisions in acquiring and continuing to hold, or in continuing
to hold, such Senior Debt.

                                      -85-
<PAGE>

SECTION 12.9    Rights of Trustee as Holder of Senior Debt; Preservation of
                -----------------------------------------------------------
                Trustee's Rights.
                -----------------

     The Trustee in its individual capacity shall be entitled to all the rights
set forth in this Article with respect to any Senior Debt which may at any time
be held by it, to the same extent as any other holder of Senior Debt, and
nothing in this Indenture shall deprive the Trustee of any of its rights as such
holder.

     Nothing in this Article shall apply to claims of, or payments to, the
Trustee under or pursuant to Section 6.7.
                             -----------

SECTION 12.10   Article Applicable to Paying Agents.
                -----------------------------------

     In case at any time any Paying Agent other than the Trustee shall have been
appointed by the Company and be then acting hereunder, the term "Trustee" as
used in this Article shall in such case (unless the context otherwise requires)
be construed as extending to and including such Paying Agent within its meaning
as fully for all intents and purposes as if such Paying Agent were named in this
Article in addition to or in place of the Trustee; provided, however, that
                                                   --------  -------
Section 12.9 shall not apply to the Company or any Affiliate of the Company if
------------
it or such Affiliate acts as Paying Agent.

SECTION 12.11   Certain Conversions and Repurchases Deemed Payment.
                --------------------------------------------------

     For the purposes of this Article only, (1) the issuance and delivery of
junior securities upon conversion of Securities in accordance with Article
                                                                   -------
Eleven or upon the repurchase of Securities in accordance with Article Thirteen
------                                                         ----------------
shall not be deemed to constitute a payment or distribution on account of the
principal of or premium, if any (including the Make-Whole Payment, if any) or
interest on Securities or on account of the purchase or other acquisition of
Securities, and (2) the payment, issuance or delivery of cash, property or
securities (other than junior securities) upon conversion of a Security shall be
deemed to constitute payment on account of the principal of such Security.  For
the purposes of this Section, the term "junior securities" means (a) shares of
any stock of any class of the Company and any cash, property or securities into
which the Securities are convertible pursuant to Article Eleven and (b)
                                                 --------------
securities of the Company which are subordinated in right of payment to all
Senior Debt which may be outstanding at the time of issuance or delivery of such
securities to substantially the same extent as, or to a greater extent than, the
Securities are so subordinated as provided in this Article.  Nothing contained
in this Article or elsewhere in this Indenture or in the Securities is intended
to or shall impair, as among the Company, its creditors other than holders of
Senior Debt and the Holders of the Securities, the right, which is absolute and
unconditional, of the Holder of any Security to convert such Security in
accordance with Article Eleven or to exchange such Security for Common Stock in
                --------------
accordance with Article Thirteen if the Company elects to satisfy the
                ----------------
obligations under Article Thirteen by the delivery of Common Stock.
                  ----------------

                                      -86-
<PAGE>

                                 ARTICLE XIII

                 REPURCHASE OF SECURITIES AT THE OPTION OF THE
                        HOLDER UPON A CHANGE IN CONTROL

SECTION 13.1   Right to Require Repurchase.
               ---------------------------

     In the event that a Change in Control (as hereinafter defined) shall occur,
then each Holder shall have the right, at the Holder's option, but subject to
the provisions of Section 13.2, to require the Company to repurchase, and upon
                  ------------
the exercise of such right the Company shall repurchase, all of such Holder's
Securities not theretofore called for redemption, or any portion of the
principal amount thereof that is equal to U.S.$1,000 or any integral multiple of
U.S.$1,000, on the date (the "Repurchase Date") that is 45 days after the date
of the Company Notice (as defined in Section 13.3) at a purchase price equal to
                                     ------------
100% of the principal amount of the Securities to be repurchased plus interest
accrued to the Repurchase Date (the "Repurchase Price"); provided, however, that
                                                         --------  -------
installments of interest on Securities whose Stated Maturity is on or prior to
the Repurchase Date shall be payable to the Holders of such Securities, or one
or more Predecessor Securities, registered as such on the relevant Record Date
according to their terms and the provisions of Section 3.7.  Such right to
                                               -----------
require the repurchase of the Securities shall not continue after a discharge of
the Company from its obligations with respect to the Securities in accordance
with Article Four, unless a Change in Control shall have occurred prior to such
     ------------
discharge. At the option of the Company, the Repurchase Price may be paid in
cash or, subject to the fulfillment by the Company of the conditions set forth
Section 13.2, by delivery of shares of Common Stock having a fair market value
------------
equal to the Repurchase Price. Whenever in this Indenture (including Sections
                                                                     --------
2.2, 3.1, 5.1(1) and 5.8) 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 provision of this Indenture
shall not be construed as excluding the Repurchase Price in those provisions of
this Indenture when such express mention is not made; provided, however, that
                                                      ----------------
for the purposes of Article Thirteen such reference shall be deemed to include
                    ----------------
reference to the Repurchase Price only to the extent the Repurchase Price is
payable in cash.

SECTION 13.2   Conditions to the Company's Election to Pay the Repurchase Price
               ----------------------------------------------------------------
               in Common Stock.
               ---------------

     The Company may elect to pay the Repurchase Price by delivery of shares of
Common Stock pursuant to Section 13.1 if and only if the following conditions
                         ------------
shall have been satisfied:

     (a)  The shares of Common Stock deliverable in payment of the Repurchase
Price shall have a fair market value as of the Repurchase Date of not less than
the Repurchase Price.  For purposes of Section 13.1 and this Section 13.2, the
                                       ------------          ------------
fair market value of shares of Common

                                      -87-
<PAGE>

Stock shall be determined by the Company and shall be equal to 95% of the
average of the Closing Price Per Share for the five consecutive Trading Days
immediately preceding and including the third Trading Day prior to the
Repurchase Date;

     (b)  The Repurchase Price shall be paid only in cash in the event any
shares of Common Stock to be issued upon repurchase of Securities hereunder (i)
require registration under any federal securities law before such shares may be
freely transferable without being subject to any transfer restrictions under the
Securities Act upon repurchase and if such registration is not completed or does
not become effective prior to the Repurchase Date, and/or (ii) require
registration with or approval of any governmental authority under any state law
or any other federal law before such shares may be validly issued or delivered
upon repurchase and if such registration is not completed or does not become
effective or such approval is not obtained prior to the Repurchase Date.  Prior
to paying all or any portion of the Repurchase Price in Common Stock, the
Company shall deliver to the Trustee an opinion of counsel to the Company to the
effect that the shares of Common Stock to be issued upon repurchase (other than
any shares to be issued to any Affiliate of the Company) are not subject to any
restrictions on transfer under the Securities Act;

     (c)  Payment of the Repurchase Price may not be made in Common Stock unless
such stock is, or shall have been, approved for quotation on the Nasdaq National
Market or listing or quotation on a national securities exchange or quotation
system, in either case, prior to the Repurchase Date; and

     (d)  All shares of Common Stock which may be issued upon repurchase of
Securities will be issued out of the Company's authorized but unissued Common
Stock and, will upon issue, be duly and validly issued and fully paid and non-
assessable and free of any preemptive rights.

     If all of the conditions set forth in this Section 13.2 are not satisfied
                                                ------------
in accordance with the terms thereof, the Company shall so certify to the
Trustee in an Officer's Certificate and the Repurchase Price shall be paid by
the Company only in cash.

SECTION 13.3    Notices; Method of Exercising Repurchase Right, Etc.
                ----------------------------------------------------

     (a)  Unless the Company shall have theretofore called for redemption all of
the Outstanding Securities, on or before the 30th day after the occurrence of a
Change in Control, the Company or, at the request and expense of the Company on
or before the 30th day after such occurrence, the Trustee, shall give to all
Holders of Securities, in the manner provided in Section 1.6, notice (the
                                                 -----------
"Company Notice") of the occurrence of the Change of Control and of the
repurchase right set forth herein arising as a result thereof and the Company
shall issue a Press Release including all relevant information required to be
included in such Company

                                      -88-
<PAGE>

Notice. The Company shall also deliver a copy of such notice of a repurchase
right to the Trustee.

     Each notice of a repurchase right shall state:

          (1)   the Repurchase Date,

          (2)   the date by which the repurchase right must be exercised,

          (3)   the Repurchase Price, and whether the Repurchase Price shall be
paid by the Company in cash or by delivery of shares of Common Stock.

          (4)   a description of the procedure which a Holder must follow to
exercise a repurchase right, and the place or places where such Securities are
to be surrendered for payment of the Repurchase Price and accrued interest, if
any,

          (5)   that on the Repurchase Date the Repurchase Price, and accrued
interest, if any, will become due and payable upon each such Security designated
by the Holder to be repurchased, and that interest thereon shall cease to accrue
on and after said date,

          (6)   the Conversion Rate then in effect, the date on which the right
to convert the principal amount of the Securities to be repurchased will
terminate and the place or places where such Securities may be surrendered for
conversion,

          (7)   the place or places that the certificate required by Section 2.2
shall be delivered, and

          (8)   the CUSIP number or numbers of such Securities.

     No failure of the Company to give the foregoing notices or defect therein
shall limit any Holder's right to exercise a repurchase right or affect the
validity of the proceedings for the repurchase of Securities.

     If any of the foregoing provisions or other provisions of this Article
                                                                    -------
Thirteen are inconsistent with applicable law, such law shall govern.
--------

     (b)  To exercise a repurchase right, a Holder shall deliver to the Trustee
on or before the 30th day after the date of the Company Notice (i) written
notice of the Holder's exercise of such right, which notice shall set forth the
name of the Holder, the principal amount of the Securities to be repurchased
(and, if any Security is to repurchased in part, the serial number thereof, the
portion of the principal amount thereof to be repurchased and the name of the
Person in which the portion thereof to remain Outstanding after such repurchase
is to be registered) and

                                      -89-
<PAGE>

a statement that an election to exercise the repurchase right is being made
thereby, and, in the event that the Repurchase Price shall be paid in shares of
Common Stock, the name or names (with addresses) in which the certificate or
certificates for shares of Common Stock shall be issued, and (ii) the Securities
with respect to which the repurchase right is being exercised. Such written
notice shall be irrevocable, except that the right of the Holder to convert the
Securities with respect to which the repurchase right is being exercised shall
continue until the close of business on the Repurchase Date.

     (C)  In the event a repurchase right shall be exercised in accordance with
the terms hereof, the Company shall pay or cause to be paid to the Trustee the
Repurchase Price in cash or shares of Common Stock, as provided above, for
payment to the Holder on the Repurchase Date or, if shares of Common Stock are
to be paid, as promptly after the Repurchase Date as practicable; provided,
                                                                  --------
however, that installments of interest on the Securities whose Stated Maturity
-------
is on or prior to the Repurchase Date shall be payable in cash to the Holders of
such Securities, or one or more Predecessor Securities, registered as such at
the close of business on the relevant Record Date.

     (d)  If any Security (or portion thereof) surrendered for repurchase shall
not be so paid on the Repurchase Date, the principal amount of such Security (or
portion thereof, as the case may be) shall, until paid, bear interest to the
extent permitted by applicable law from the Repurchase Date at the rate then in
effect per annum, and each Security shall remain convertible into Common Stock
until the principal of such Security (or portion thereof, as the case may be)
shall have been paid or duly provided for.

     (e)  Any Security which is to be repurchased only in part shall be
surrendered to the Trustee (with, if the Company or the Trustee so requires, due
endorsement by, or a written instrument of transfer in form satisfactory to the
Company and the Trustee duly executed by, the Holder thereof or his attorney
duly authorized in writing), and the Company shall execute, and the Trustee
shall authenticate and make available for delivery to the Holder of such
Security without service charge, a new Security or Securities, containing
identical terms and conditions, each in an authorized denomination in aggregate
principal amount equal to and in exchange for the unrepurchased portion of the
principal of the Security so surrendered.

     (f)  Any issuance of shares of Common Stock in respect of the Repurchase
Price shall be deemed to have been effected immediately prior to the close of
business on the Repurchase Date and the Person or Persons in whose name or names
any certificate or certificates for shares of Common Stock shall be issuable
upon such repurchase shall be deemed to have become on the Repurchase Date the
holder or holders of record of the shares represented thereby; provided,
                                                               --------
however, that any surrender for repurchase on a date when the stock transfer
-------
books of the Company shall be closed shall constitute the Person or Persons in
whose name or names the certificate or certificates for such shares are to be
issued as the record holder or holders thereof for all purposes at the opening
of business on the next succeeding day on which such stock

                                      -90-
<PAGE>

transfer books are open. No payment or adjustment shall be made for dividends or
distributions on any Common Stock issued upon repurchase of any Security
declared prior to the Repurchase Date.

     (g)  No fractions of shares shall be issued upon repurchase of Securities.
If more than one Security shall be repurchased from the same Holder and the
Repurchase Price shall be payable in shares of Common Stock, the number of full
shares which shall be issuable upon such repurchase shall be computed on the
basis of the aggregate principal amount of the Securities so repurchased.
Instead of any fractional share of Common Stock which would otherwise be
issuable on the repurchase of any Security or Securities, the Company will
deliver to the applicable Holder its check for the current market value of such
fractional share.  The current market value of a fraction of a share is
determined by multiplying the current market price of a full share by the
fraction, and rounding the result to the nearest cent.  For purposes of this
Section, the current market price of a share of Common Stock is the Closing
Price Per Share of the Common Stock on the Trading Day immediately preceding the
Repurchase Date.

     (h)  Any issuance and delivery of certificates for shares of Common Stock
on repurchase of Securities shall be made without charge to the Holder of
Securities being repurchased for such certificates or for any tax or duty in
respect of the issuance or delivery of such certificates or the securities
represented thereby; provided, however, that the Company shall not be required
                     --------  -------
to pay any tax or duty which may be payable in respect of (i) income of the
Holder or (ii) any transfer involved in the issuance or delivery of certificates
for shares of Common Stock in a name other than that of the Holder of the
Securities being repurchased, and no such issuance or delivery shall be made
unless and until the Person requesting such issuance or delivery has paid to the
Company the amount of any such tax or duty or has established, to the
satisfaction of the Company, that such tax or duty has been paid.

     (i)  All Securities delivered for repurchase shall be delivered to the
Trustee to be canceled by the Trustee and disposed of as provided in Section
                                                                     -------
3.9.
---


SECTION 13.4   Certain Definitions.
               -------------------

     For purposes of this Article Thirteen,
                          ----------------

     (a)    the term "beneficial owner" shall be determined in accordance with
Rule 13d-3, as in effect on the date of the original execution of this
Indenture, promulgated by the Commission pursuant to the Exchange Act;

     (b)    a "Change in Control" will be deemed to have occurred at the time
after the Securities are originally issued that any of the following occurs:

                                      -91-
<PAGE>

          (i)    any Person, including any syndicate or group deemed to be a
"person" under Section 13(d)(3) of the Exchange Act, acquires beneficial
ownership, directly or indirectly, through a purchase, merger or other
acquisition transaction or series of transactions, of shares of the Company's
capital stock entitling that Person to exercise 50% or more of the total voting
power of all shares of the Company's capital stock entitled to vote generally in
elections of directors; however, any acquisition by the Company, any Subsidiary
of the Company or any employee benefit plan of the Company and any merger or
consolidation that is not a Change in Control under clause (ii) below will not
trigger this provision;

         (ii)    the Company consolidates with or merges with or into any other
Person or another Person merges into the Company, except if the transaction
satisfies any of the following: (x) the holders of 50% or more of the total
voting power of all shares of the Company's capital stock entitled to vote
generally in elections of directors immediately prior to the transaction have,
directly or indirectly, 50% or more of the total voting power of all shares of
capital stock of the continuing or surviving corporation entitled to vote
generally in elections of directors of the continuing or surviving corporation
immediately after the transaction; (y) the transaction is a merger which does
not result in any reclassification, conversion, exchange or cancellation of
outstanding shares of the Company's capital stock; or (z) the transaction is a
merger effected only to change the Company's jurisdiction of incorporation and
it results in a reclassification, conversion or exchange of outstanding shares
of the Company's common stock only into other shares of Common Stock or shares
of common stock of another corporation; or

        (iii)    the Company conveys, transfers, sells, leases or otherwise
disposes of all or substantially all of its assets to another Person, unless the
holders of 50% or more of the total voting power of all shares of capital stock
of the Company entitled to vote generally in elections of directors immediately
prior to the consummation of such transaction have, directly or indirectly, 50%
or more of the total voting power of all shares of capital stock of such Person
entitled to vote generally in elections of directors immediately after the
consummation of such transaction.

     However, a Change in Control shall not be deemed to have occurred if (x)
the Closing Price Per Share on any five Trading Days within the period of 10
consecutive Trading Days ending immediately after the later of the date of the
Change in Control or the date of the public announcement of the Change in
Control (in the case of a Change in Control under Clause (i) above), or within
the period of 10 consecutive Trading Days ending immediately prior to the date
the Change in Control (in the case of a Change in Control under Clause (ii) or
(iii) above), shall in the case of each of such five Trading Days equal or
exceed 105% of the Conversion Price of the Securities in effect on such Trading
Day or (y) all of the consideration, excluding cash payments for fractional
shares and cash payments made pursuant to dissenters' appraisal rights, in a
merger or consolidation otherwise constituting a Change in Control under Section
13.4(b)(i) or (ii) consists of shares of common stock traded on a national
securities exchange or quoted on the Nasdaq National Market, or will be so
traded or quoted immediately following such merger

                                      -92-
<PAGE>

or consolidation as a result of such merger or consolidation the Securities
become convertible solely into such common stock.

     (c)   the term "Conversion Price" shall equal U.S.$1,000 divided by the
Conversion Rate; and

     (d)   for purposes of Section 13.4(b)(i), the term "Person" shall include
                          ------------------
any syndicate or group which would be deemed to be a "Person" under Section
13(d)(3) of the Exchange Act, as in effect on the date of the original execution
of this Indenture.

                                  ARTICLE XIV

                           HOLDERS LISTS AND REPORTS
                     BY TRUSTEE AND COMPANY; NON-RECOURSE

SECTION 14.1   Company to Furnish Trustee Names and Addresses of Holders.
               ---------------------------------------------------------

     The Company will furnish or cause to be furnished to the Trustee:

      (a)  semi-annually, not more than 15 days after the Regular Record Date, a
list, in such form as the Trustee may reasonably require, of the names and
addresses of the Holders of Securities as of such Regular Record Date, and

      (b)  at such other times as the Trustee may reasonably request in writing,
within 30 days after the receipt by the Company of any such request, a list of
similar form and content as of a date not more than 15 days prior to the time
such list is furnished;

excluding from any such list names and addresses received by the Trustee in its
capacity as Security Registrar.

SECTION 14.2   Preservation of Information.
               ---------------------------

      (a)  The Trustee shall preserve, in as current a form as is reasonably
practicable, the names and addresses of Holders contained in the most recent
list furnished to the Trustee as provided in Section 14.1 and the names and
                                             ------------
addresses of Holders received by the Trustee in its capacity as Security
Registrar.  The Trustee may destroy any list furnished to it as provided in
Section 14.1 upon receipt of a new list so furnished.
------------

      (b)  After this Indenture has been qualified under the Trust Indenture
Act, the rights of Holders to communicate with other Holders with respect to
their rights under this Indenture or under the Securities, and the corresponding
rights and duties of the Trustee, shall be as provided by the Trust Indenture
Act.

                                      -93-
<PAGE>

      (c)  Every Holder of Securities, by receiving and holding the same, agrees
with the Company and the Trustee that neither the Company nor the Trustee nor
any agent of either of them shall be held accountable by reason of any
disclosure of information as to names and addresses of Holders made pursuant to
the Trust Indenture Act.


SECTION 14.3   No Recourse Against Others.
               --------------------------

     An incorporator or any past, present or future director, officer, employee
or stockholder, as such, of the Company shall not have any liability for any
obligations of the Company under the Securities or this Indenture or for any
claim based on, in respect of or by reason of such obligations or their
creation.  By accepting a Security, each Holder shall waive and release all such
liability.  Such waiver and release shall be part of the consideration for the
issue of the Securities.

SECTION 14.4   Reports by Trustee.
               ------------------

      (a)  The Trustee shall transmit to Holders such reports concerning the
Trustee and its actions under this Indenture as may be required pursuant to the
Trust Indenture Act at the times and in the manner provided pursuant thereto.
If required by Section 313(a) of the Trust Indenture Act, the Trustee shall,
within sixty days after each September  15 following the date of this Indenture,
deliver to Holders a brief report, dated as of such September  15, which
complies with the provisions of such Section 313(a).
                                     --------------

      (b)  A copy of each such report shall, at the time of such transmission to
Holders, be filed by the Trustee with each stock exchange upon which the
Securities are listed, with the Commission and with the Company.  The Company
will promptly notify the Trustee when the Securities are listed on any stock
exchange.

SECTION 14.5   Reports by Company.
               ------------------

     The Company shall file with the Trustee and the Commission, and transmit to
Holders, such information, documents and other reports, and such summaries
thereof, as may be required pursuant to the Trust Indenture Act at the times and
in the manner provided pursuant thereto; provided that any such information,
                                         --------
documents or reports required to be filed with the Commission pursuant to
Section 13 or 15(d) of the Exchange Act shall be filed with the Trustee within
15 days after the same is so required to be filed with the Commission.

     Delivery of such reports, information and documents to the Trustee is for
informational purposes only and the Trustee's receipt thereof shall not
constitute constructive notice of any information contained therein or
determinable from information contained therein, including the Company's
compliance with any of its covenants hereunder (as to which the Trustee is
entitled to rely exclusively on Officers' Certificates).

                                      -94-
<PAGE>

                                  ARTICLE XV

                                   IMMUNITY

SECTION 15.1   Personal Immunity of Incorporators, Shareholders, Directors and
               ---------------------------------------------------------------
               Officers.
               --------

     No recourse for the payment of the principal of or interest on the
Securities, and no recourse under or upon any obligation, covenant or agreement
contained in this Indenture or in any indenture supplemental hereto, or in the
Securities, or because of any indebtedness evidenced thereby, shall be had
against any incorporator, or against any past, present or future shareholder,
officer or director, as such,  of the Company or any successor corporation,
either directly or through the Company or any successor corporation, under any
rule of law, statute or constitutional provision or by the enforcement of any
assessment or by any legal or equitable proceeding or otherwise, all such
liability being expressly waived and released by the acceptance of the
Securities by the Holders thereof and as part of the consideration for the issue
of the Securities.  Each and every Holder of the Securities, by receiving and
holding the same, agrees to the provisions of this Section 15.1 and waives and
releases any and all such recourse, claim and liability.

                          ___________________________

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

                                      -95-
<PAGE>

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

                              MEDAREX, INC.


                              By: /s/ Christian Schade
                                  ------------------------------------
                                  Name:  Christian Schade
                                  Title: Chief Financial Officer



                              WILMINGTON TRUST COMPANY, as Trustee


                              By: /s/ Michael W. Diaz
                                  ------------------------------------
                                  Name:  Michael W. Diaz
                                  Title: Authorized Signer



                                      -96-