Document:

Seventeenth Supplemental Indenture

 EXHIBIT 4.1 

 D.R. HORTON, INC. AND THE GUARANTORS PARTY HERETO 
  
 5.875% Senior Notes due 2013 
  

  
 Seventeenth Supplemental Indenture

  
 Dated as of June 25, 2003 
  

  
 AMERICAN STOCK TRANSFER & TRUST COMPANY, 
 Trustee 
  

 TABLE OF CONTENTS 
  

	 	  	Page

		
	 ARTICLE ONE Scope of Supplemental Indenture; General
	  	2
		
	 ARTICLE TWO Certain Definitions
	  	2
		
	 ARTICLE THREE Covenants
	  	25
			
	 Section 3.01.
	  	Repurchase of Notes upon Change of Control.	  	25
	 Section 3.02.
	  	Limitations on Indebtedness.	  	26
	 Section 3.03.
	  	Limitations on Restricted Payments.	  	27
	 Section 3.04.
	  	Limitations on Transactions with Affiliates.	  	29
	 Section 3.05.
	  	Limitations on Dispositions of Assets.	  	30
	 Section 3.06.
	  	Limitations on Liens.	  	31
	 Section 3.07.
	  	Limitations on Restrictions Affecting Restricted Subsidiaries.	  	31
	 Section 3.08.
	  	Limitations on Mergers, Consolidations and Sales of Assets.	  	32
	 Section 3.09.
	  	Reports to Holders of Notes.	  	33
		
	 ARTICLE FOUR Miscellaneous
	  	33
			
	 Section 4.01.
	  	Governing Law.	  	33
	 Section 4.02.
	  	No Adverse Interpretation of Other Agreements.	  	33
	 Section 4.03.
	  	No Recourse Against Others.	  	34
	 Section 4.04.
	  	Successors and Assigns.	  	34
	 Section 4.05.
	  	Duplicate Originals.	  	34
	 Section 4.06.
	  	Severability.	  	34

  

 i 

 SEVENTEENTH SUPPLEMENTAL INDENTURE dated as of June 25, 2003 (“Supplemental Indenture”),
to the Indenture dated as of June 9, 1997 (as amended, modified or supplemented from time to time in accordance therewith, the “Indenture”), by and among D.R. HORTON, INC., a Delaware corporation (the “Company”),
each of the Guarantors (as defined herein) and AMERICAN STOCK TRANSFER & TRUST COMPANY, as trustee (the “Trustee”). 
  
 Each party agrees as follows for the benefit of the other party and for the equal and ratable benefit of the holders of Notes (as defined herein):

  
 WHEREAS, the Company, the Guarantors and the Trustee have
duly authorized the execution and delivery of the Indenture to provide for the issuance from time to time of senior debt securities (the “Securities”) to be issued in one or more series as in the Indenture provided; 
  
 WHEREAS, the Company and the Guarantors desire and have requested the Trustee
to join them in the execution and delivery of this Supplemental Indenture in order to establish and provide for the issuance by the Company of a series of Securities designated as its 5.875% Senior Notes due 2013, substantially in the form attached
hereto as Exhibit A (the “Notes”), guaranteed by the Guarantors, on the terms set forth herein; 
  
 WHEREAS, Section 2.01 of the Indenture provides that a supplemental indenture may be entered into by the Company, the Guarantors and the Trustee for such
purpose provided certain conditions are met; 
  
 WHEREAS, the
conditions set forth in the Indenture for the execution and delivery of this Supplemental Indenture have been complied with; and 
  
 WHEREAS, all things necessary to make this Supplemental Indenture a valid agreement of the Company, the Guarantors and the Trustee, in accordance with its
terms, and a valid amendment of, and supplement to, the Indenture have been done; 
  
 NOW, THEREFORE: 
  
 In
consideration of the premises and the purchase and acceptance of the Notes by the holders thereof the Company and the Guarantors mutually covenant and agree with the Trustee, for the equal and ratable benefit of the holders, that the Indenture is
supplemented and amended, to the extent expressed herein, as follows: 

 ARTICLE ONE 
  
 Scope of Supplemental Indenture; General 
  
 The changes, modifications and supplements to the Indenture effected by this Supplemental Indenture shall be applicable only
with respect to, and govern the terms of, the Notes, which shall not be limited in aggregate principal amount, and shall not apply to any other Securities that may be issued under the Indenture unless a supplemental indenture with respect to such
other Securities specifically incorporates such changes, modifications and supplements. Pursuant to this Supplemental Indenture, there is hereby created and designated a series of Securities under the Indenture entitled “5.875% Senior Notes due
2013.” The Notes shall be in the form of Exhibit A hereto. The Notes shall be guaranteed by the Guarantors as provided in such form and the Indenture. If required, the Notes may bear an appropriate legend regarding original issue
discount for federal income tax purposes. 
  
 In the event that
less than all of the Notes are to be redeemed at any time pursuant to an optional redemption, selection of the Notes for redemption will be made by the Trustee in compliance with the requirements of the principal national securities exchange, if
any, on which the Notes are listed or, if the Notes are not then listed on a national security exchange, on a pro rata basis, by lot or by such method as the Trustee shall deem fair and appropriate. In addition, if a partial redemption is made
pursuant to paragraph 5(b) of the Notes, selection of the Notes or portions thereof for redemption shall be made by the Trustee only on a pro rata basis or on as nearly a optional redemption basis as is practicable (subject to the procedures of the
Depository Trust Company), unless that method is otherwise prohibited. 
  
 ARTICLE TWO 
  
 Certain Definitions

  
 The following terms have the meanings set forth below in
this Supplemental Indenture. Capitalized terms used but not defined herein have the meanings ascribed to such terms in the Indenture. To the extent terms defined herein differ from the Indenture the terms defined herein will govern. 
  
 “Acquired Indebtedness” means (i) with respect to any Person
that becomes a Restricted Subsidiary (or is merged into the Company or any Restricted Subsidiary) after the Issue Date, Indebtedness of such Person or any of its Subsidiaries existing at the time such Person becomes a Restricted Subsidiary (or is
merged into the Company or any Restricted Subsidiary) that was not incurred in connection with, or in contemplation of, such Person becoming a Restricted Subsidiary (or being merged into the Company or any Restricted Subsidiary) and (ii) with
respect to the Company or any Restricted Subsidiary, any Indebtedness expressly assumed 

  

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by the Company or any Restricted Subsidiary in connection with the acquisition of any assets from another Person (other than the Company or any Restricted
Subsidiary), which Indebtedness was not incurred by such other Person in connection with or in contemplation of such acquisition. Indebtedness incurred in connection with or in contemplation of any transaction described in clause (i) or (ii) of the
preceding sentence shall be deemed to have been incurred by the Company or a Restricted Subsidiary, as the case may be, at the time such Person becomes a Restricted Subsidiary (or is merged into the Company or any Restricted Subsidiary) in the case
of clause (i) or at the time of the acquisition of such assets in the case of clause (ii), but shall not be deemed Acquired Indebtedness. 
  
 “Affiliate” means, when used with reference to a specified Person, any Person directly or indirectly controlling or controlled by or
under direct or indirect common control with the Person specified. 
  
 “Affiliate Transaction” has the meaning set forth in Section 3.03 hereof. 
  
 “Asset Acquisition” means (i) an Investment by the Company or any Restricted Subsidiary in any other Person if, as a result of such
Investment, such Person shall become a Restricted Subsidiary or shall be consolidated or merged with or into the Company or any Restricted Subsidiary or (ii) the acquisition by the Company or any Restricted Subsidiary of the assets of any Person,
which constitute all or substantially all of the assets or of an operating unit or line of business of such Person or which is otherwise outside the ordinary course of business. 
  
 “Asset Disposition” means any sale, transfer, conveyance, lease or other disposition (including, without
limitation, by way of merger, consolidation or sale and leaseback or sale of shares of Capital Stock in any Subsidiary) (each, a “transaction”) by the Company or any Restricted Subsidiary to any Person of any Property having a fair
market value in any transaction or series of related transactions of at least $10 million. The term “Asset Disposition” shall not include (i) a transaction between the Company and any Restricted Subsidiary or a transaction between
Restricted Subsidiaries, (ii) a transaction in the ordinary course of business, including, without limitation, sales (directly or indirectly), dedications and other donations to governmental authorities, leases and sales and leasebacks of (A) homes,
improved land and unimproved land and (B) real estate (including related amenities and improvements), (iii) a transaction involving the sale of Capital Stock of, or the disposition of assets in, an Unrestricted Subsidiary, (iv) any exchange or swap
of assets of the Company or any Restricted Subsidiary for assets that (x) are to be used by the Company or any Restricted Subsidiary in the ordinary course of its Real Estate Business and (y) have a Fair Market Value not less than the Fair Market
Value of the assets exchanged or swapped, (v) any sale, transfer, conveyance, lease or other disposition of assets and properties of the Company that is governed by Section 3.08 hereof, or (iv) dispositions of mortgage loans and related assets and

  

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3.08 hereof, or (iv) dispositions of mortgage loans and related assets and mortgage-backed securities in the ordinary course of a mortgage lending business.

  
 “Attributable Debt” means, with respect to
any Capitalized Lease Obligations, the capitalized amount thereof determined in accordance with GAAP. 
  
 “Bankruptcy Law” means title 11 of the United States Code, as amended, or any similar federal or state law for the relief of debtors.

  
 “Business Day” means each Monday, Tuesday,
Wednesday, Thursday and Friday which is not a day on which banking institutions in New York, New York are authorized or obligated by law or executive order to close. 
  
 “Capital Stock” means, with respect to any Person, any and all shares, interests, participations or other
equivalents (however designated) of or in such Person’s capital stock or other equity interests, and options, rights or warrants to purchase such capital stock or other equity interests, whether now outstanding or issued after the Issue Date,
including, without limitation, all Disqualified Stock and Preferred Stock. 
  
 “Capitalized Lease Obligations” of any Person means the obligations of such Person to pay rent or other amounts under a lease that is required to be capitalized for financial reporting purposes in
accordance with GAAP, and the amount of such obligations will be the capitalized amount thereof determined in accordance with GAAP. 
  
 “Cash Equivalents” means: (a) U.S. dollars; (b) securities issued or directly and fully guaranteed or insured by the U.S. government or
any agency or instrumentality thereof having maturities of one year or less from the date of acquisition; (c) certificates of deposit and eurodollar time deposits with maturities of one year or less from the date of acquisition, bankers’
acceptances with maturities not exceeding six months and overnight bank deposits, in each case with any domestic commercial bank having capital and surplus in excess of $500 million; (d) repurchase obligations with a term of not more than seven days
for underlying securities of the types described in clauses (b) and (c) entered into with any financial institution meeting the qualifications specified in clause (c) above; (e) commercial paper rated P-1, A-1 or the equivalent thereof by
Moody’s Investors Service, Inc. or Standard & Poor’s Ratings Group, respectively, and in each case maturing within six months after the date of acquisition; and (f) investments in money market funds substantially all of the assets of
which consist of securities described in the foregoing clauses (a) through (e). 
  
 “Change of Control” means (i) any sale, lease or other transfer (in one transaction or a series of transactions) of all or substantially all of the consolidated assets of the Company and its
Restricted Subsidiaries to any Person (other than a Restricted Subsidiary); 

  

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provided, however, that a transaction where the holders of all classes of Common Equity of the Company immediately prior to such transaction
own, directly or indirectly, more than 50% of all classes of Common Equity of such Person immediately after such transaction shall not be a Change of Control; (ii) a “person” or “group” (within the meaning of Section 13(d) of the
Exchange Act (other than (x) the Company or (y) Donald R. Horton, Terrill J. Horton, or their respective wives, children, grandchildren and other descendants, or any trust or other entity formed or controlled by any of such individuals)) becomes the
“beneficial owner” (as defined in Rule 13d-3 under the Exchange Act) of Common Equity of the Company representing more than 50% of the voting power of the Common Equity of the Company; (iii) Continuing Directors cease to constitute at
least a majority of the Board of Directors of the Company; or (iv) the stockholders of the Company approve any plan or proposal for the liquidation or dissolution of the Company; provided, however, that a liquidation or dissolution of
the Company which is part of a transaction that does not constitute a Change of Control under the proviso contained in clause (i) above shall not constitute a Change of Control. 
  
 “Common Equity” of any Person means Capital Stock of such Person that is generally entitled to (i) vote in
the election of directors of such Person or (ii) if such Person is not a corporation, vote or otherwise participate in the selection of the governing body, partners, managers or others that will control the management or policies of such Person.

  
 “Consolidated Adjusted Tangible Assets” of
the Company as of any date means the Consolidated Tangible Assets of the Company and the Restricted Subsidiaries at the end of the fiscal quarter immediately preceding the date less any assets securing any Non-Recourse Indebtedness, as determined in
accordance with GAAP. 
  
 “Consolidated Cash Flow
Available for Fixed Charges” means, for any period, on a consolidated basis for the Company and the Restricted Subsidiaries, Consolidated Net Income for such period plus (each to the extent deducted in calculating such Consolidated Net
Income and determined in accordance with GAAP) (a) the sum for such period, without duplication, of (i) income taxes, (ii) Consolidated Interest Expense, (iii) depreciation and amortization expenses and other non-cash charges to earnings and (iv)
interest and financing fees and expenses which were previously capitalized and which are amortized to cost of sales, minus (b) all other non-cash items (other than the receipt of notes receivable) increasing such Consolidated Net Income. 

 
 “Consolidated Fixed Charge Coverage Ratio” means, with
respect to any determination date, the ratio of (x) Consolidated Cash Flow Available for Fixed Charges for the prior four full fiscal quarters (the “Four Quarter Period”) for which financial results have been reported immediately
preceding the determination date (the “Transaction Date”), to (y) the aggregate Consolidated Interest Incurred for the Four Quarter Period. For purposes of this 

  

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definition, “Consolidated Cash Flow Available for Fixed Charges” and “Consolidated Interest Incurred” shall be calculated after giving
effect on a pro forma basis for the period of such calculation to (i) the incurrence or the repayment, repurchase, defeasance or other discharge or the assumption by another Person that is not an Affiliate (collectively,
“repayment”) of any Indebtedness of the Company or any Restricted Subsidiary (and the application of the proceeds thereof) giving rise to the need to make such calculation, and any incurrence or repayment of other Indebtedness (and
the application of the proceeds thereof), at any time on or after the first day of the Four Quarter Period and on or prior to the Transaction Date, as if such incurrence or repayment, as the case may be (and the application of the proceeds thereof),
occurred on the first day of the Four Quarter Period, except that Indebtedness under revolving credit facilities shall be deemed to be the average daily balance of such Indebtedness during the Four Quarter Period (as reduced on such pro
forma basis by the application of any proceeds of the incurrence of Indebtedness giving rise to the need to make such calculation); (ii) any Asset Disposition or Asset Acquisition (including, without limitation, any Asset Acquisition giving
rise to the need to make such calculation as a result of the Company or any Restricted Subsidiary (including any Person that becomes a Restricted Subsidiary as a result of any such Asset Acquisition) incurring Acquired Indebtedness at any time on or
after the first day of the Four Quarter Period and on or prior to the Transaction Date), as if such Asset Disposition or Asset Acquisition (including the incurrence or repayment of any such Indebtedness) and the inclusion, notwithstanding clause
(ii) of the definition of “Consolidated Net Income,” of any Consolidated Cash Flow Available for Fixed Charges associated with such Asset Acquisition as if it occurred on the first day of the Four Quarter Period; provided,
however, that the Consolidated Cash Flow Available for Fixed Charges associated with any Asset Acquisition shall not be included to the extent the net income so associated would be excluded pursuant to the definition of “Consolidated Net
Income,” other than clause (ii) thereof, as if it applied to the Person or assets involved before they were acquired; and (iii) the Consolidated Cash Flow Available for Fixed Charges and the Consolidated Interest Incurred attributable to
discontinued operations, as determined in accordance with GAAP, shall be excluded. Furthermore, in calculating “Consolidated Cash Flow Available for Fixed Charges” for purposes of determining the denominator (but not the numerator) of this
“Consolidated Fixed Charge Coverage Ratio,” (1) interest on Indebtedness in respect of which a pro forma calculation is required that is determined on a fluctuating basis as of the Transaction Date (including Indebtedness
actually incurred on the Transaction Date) and which will continue to be so determined thereafter shall be deemed to have accrued at a fixed rate per annum equal to the rate of interest on such Indebtedness in effect on the Transaction
Date; and (2) notwithstanding clause (1) above, interest on such Indebtedness determined on a fluctuating basis, to the extent such interest is covered by agreements relating to Interest Protection Agreements, shall be deemed to accrue at the rate
per annum resulting after giving effect to the operation of such agreements. 
  

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 “Consolidated Interest Expense” of the Company for any period means the Interest Expense
of the Company and the Restricted Subsidiaries for such period, determined on a consolidated basis in accordance with GAAP. 
  
 “Consolidated Interest Incurred” for any period means the Interest Incurred of the Company and the Restricted Subsidiaries for such
period, determined on a consolidated basis in accordance with GAAP. 
  
 “Consolidated Net Income” for any period means the aggregate net income (or loss) of the Company and its Subsidiaries for such period, determined on a consolidated basis in accordance with GAAP; provided that there
will be excluded from such net income (loss) (to the extent otherwise included therein), without duplication: (i) the net income (or loss) of (x) any Unrestricted Subsidiary (other than a Mortgage Subsidiary) or (y) any Person (other than a
Restricted Subsidiary) in which any Person other than the Company or any Restricted Subsidiary has an ownership interest, except, in each case, to the extent that any such income has actually been received by the Company or any Restricted Subsidiary
in the form of cash dividends or similar cash distributions during such period, which dividends or distributions are not in excess of the Company’s or such Restricted Subsidiary’s (as applicable) pro rata share of such Unrestricted
Subsidiary’s or such other Person’s net income earned during such period, (ii) except to the extent includable in Consolidated Net Income pursuant to the foregoing clause (i), the net income (or loss) of any Person that accrued prior to
the date that (a) such Person becomes a Restricted Subsidiary or is merged with or into or consolidated with the Company or any of its Restricted Subsidiaries (except, in the case of an Unrestricted Subsidiary that is redesignated a Restricted
Subsidiary during such period, to the extent of its retained earnings from the beginning of such period to the date of such redesignation) or (b) the assets of such Person are acquired by the Company or any Restricted Subsidiary, (iii) the net
income of any Restricted Subsidiary to the extent that (but only so long as) the declaration or payment of dividends or similar distributions by such Restricted Subsidiary of that income is not permitted by operation of the terms of its charter or
any agreement, instrument, judgment, decree, order, statute, rule or governmental regulation applicable to that Restricted Subsidiary during such period, (iv) the gains or losses, together with any related provision for taxes, realized during such
period by the Company or any Restricted Subsidiary resulting from (a) the acquisition of securities, or extinguishment of Indebtedness, of the Company or any Restricted Subsidiary or (b) any Asset Disposition by the Company or any Restricted
Subsidiary, (v) any extraordinary gain or loss together with any related provision for taxes, realized by the Company or any Restricted Subsidiary and (vi) any non-recurring expense recorded by the Company or any Restricted Subsidiary in connection
with a merger accounted for as a “pooling-of-interests” transaction; provided, further, that for purposes of calculating Consolidated Net Income solely as it relates to clause (iii) of Section 3.03(a) hereof, clause (iv)(b)
above shall not be applicable. 
  

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 “Consolidated Net Worth” of any Person as of any date means the stockholders’
equity (including any Preferred Stock that is classified as equity under GAAP, other than Disqualified Stock) of such Person and its Restricted Subsidiaries on a consolidated basis at the end of the fiscal quarter immediately preceding such date, as
determined in accordance with GAAP, less any amount attributable to Unrestricted Subsidiaries. 
  
 “Consolidated Tangible Assets” of the Company as of any date means the total amount of assets of the Company and its Restricted Subsidiaries (less applicable reserves) on a consolidated basis at the
end of the fiscal quarter immediately preceding such date, as determined in accordance with GAAP, less: (i) Intangible Assets and (ii) appropriate adjustments on account of minority interests of other Persons holding equity investments in Restricted
Subsidiaries. 
  
 “Continuing Director” means a
director who either was a member of the Board of Directors of the Company on the Issue Date or who became a director of the Company subsequent to such date and whose election, or nomination for election by the Company’s stockholders, was duly
approved by a majority of the Continuing Directors on the Board of Directors of the Company at the time of such approval, either by a specific vote or by approval of the proxy statement issued by the Company on behalf of the entire Board of
Directors of the Company in which such individual is named as nominee for director. 
  
 “control”, when used with respect to any 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. 
  
 “Credit Facilities” means, collectively, each of the credit facilities of the Company or one or more Restricted Subsidiaries in existence
on the Issue Date and one or more other facilities among or between the Company or one or more Restricted Subsidiaries and one or more lenders pursuant to which the Company or any Restricted Subsidiary may incur indebtedness for working capital and
general corporate purposes (including acquisitions), as any such facility or line of credit may be amended, restated, supplemented or otherwise modified from time to time, and includes any agreement extending the maturity of, increasing the amount
of, or restructuring, all or any portion of the Indebtedness under any such facility or line of credit or any successor facilities or lines of credit and includes any facility or line of credit with one or more lenders refinancing or replacing all
or any portion of the Indebtedness under such facility or line of credit or any successor facility or line of credit. 
  
 “Currency Agreement” of any Person means any foreign exchange contract, currency swap agreement or other similar agreement or arrangement
designed to protect such Person or any of its Subsidiaries against fluctuations in currency values. 
  

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 “Custodian” means any receiver, trustee, assignee, liquidator or similar official under
any Bankruptcy Law. 
  
 “Default” means any
event, act or condition that is, or after notice or the passage of time or both would be, an Event of Default. 
  
 “Designation Amount” has the meaning provided in the definition of Unrestricted Subsidiary. 
  
 “Disqualified Stock” means any Capital Stock that, by its
terms (or by the terms of any security into which it is convertible or for which it is exchangeable), or upon the happening of any event, (i) matures or is mandatorily redeemable, pursuant to a sinking fund obligation or otherwise, or is redeemable
at the option of the holder thereof, in whole or in part, on or prior to the final maturity date of the Notes or (ii) is convertible into or exchangeable or exercisable for (whether at the option of the issuer or the holder thereof) (a) debt
securities or (b) any Capital Stock referred to in (i) above, in each case, at any time prior to the final maturity date of the Notes provided, however, that any Capital Stock that would not constitute Disqualified Stock but for
provisions thereof giving holders thereof (or the holders of any security into or for which such Capital Stock is convertible, exchangeable or exercisable) the right to require the Company to repurchase or redeem such Capital Stock upon the
occurrence of a change in control occurring prior to the final maturity date of the Notes shall not constitute Disqualified Stock if the change in control provisions applicable to such Capital Stock are no more favorable to such holders than Section
3.01 hereof and such Capital Stock specifically provides that the Company will not repurchase or redeem any such Capital Stock pursuant to such provisions prior to the Company’s repurchase of the Notes as are required pursuant to Section 3.01
hereof. 
  
 “Dollars” and “$”
mean United States Dollars. 
  
 “Event of
Default” means: 
  
 (1) the failure by
the Company to pay interest on any Note when the same becomes due and payable and the continuance of any such failure for a period of 30 days; 
  
 (2) the failure by the Company to pay the principal or premium of any Note when the same becomes due and payable at maturity, upon
acceleration or otherwise; 
  
 (3) the failure by
the Company or any Restricted Subsidiary to comply with any of its agreements or covenants in, or provisions of, the Notes, the Guarantees 
  

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or the Indenture and such failure continues for the period and after the notice specified below (except in the case of a default under Section 3.01 or 3.08,
which will constitute Events of Default with notice but without passage of time); 
  
 (4) the acceleration of any Indebtedness (other than Non-Recourse Indebtedness) of the Company or any Restricted Subsidiary that has an
outstanding principal amount of $25 million or more, individually or in the aggregate, and such acceleration does not cease to exist, or such Indebtedness is not satisfied, in either case within 30 days after such acceleration; 
  
 (5) the failure by the Company or any Restricted Subsidiary
to make any principal or interest payment in an amount of $25 million or more, individually or in the aggregate, in respect of Indebtedness (other than Non-Recourse Indebtedness) of the Company or any Restricted Subsidiary within 30 days of such
principal or interest becoming due and payable (after giving effect to any applicable grace period set forth in the documents governing such Indebtedness); 
  
 (6) a final judgment or judgments that exceed $25 million or more, individually or in the aggregate, for the payment of money having been
entered by a court or courts of competent jurisdiction against the Company or any of its Restricted Subsidiaries and such judgment or judgments is not satisfied, stayed, annulled or rescinded within 60 days of being entered; 
  
 (7) the Company or any Restricted Subsidiary that is a
Significant Subsidiary pursuant to or within the meaning of any Bankruptcy Law: 
  
 (A) commences a voluntary case, 
  
 (B) consents to the entry of an order for relief against it in an involuntary case, 
  
 (C) consents to the appointment of a Custodian of it or for
all or substantially all of its property, or 
  
 (D) makes a general assignment for the benefit of its creditors; 
  
 (8) a court of competent jurisdiction enters an order or decree under any Bankruptcy Law that: 
  
 (A) is for relief against the Company or any Restricted Subsidiary that is a Significant Subsidiary as debtor in an involuntary case,

  

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 (B) appoints a Custodian of the Company or any Restricted Subsidiary that is a
Significant Subsidiary or a Custodian for all or substantially all of the property of the Company or any Restricted Subsidiary that is a Significant Subsidiary, or 
  
 (C) orders the liquidation of the Company or any Restricted Subsidiary that is a Significant Subsidiary,

  
 and the order or decree remains unstayed and
in effect for 60 days; or 
  
 (9) any Guarantee
of a Guarantor which is a Significant Subsidiary ceases to be in full force and effect (other than in accordance with the terms of such Guarantee and the Indenture) or is declared null and void and unenforceable or found to be invalid or any
Guarantor denies its liability under its Guarantee (other than by reason of release of a Guarantor from its Guarantee in accordance with the terms of the Indenture and the Guarantee). 
  
 “Fair Market Value” means, with respect to any asset, the price (after taking into account any liabilities
relating to such assets) that would be negotiated in an arm’s-length transaction for cash between a willing seller and a willing and able buyer, neither of which is under any compulsion to complete the transaction, as such price is determined
in good faith by the Board of Directors of the Company or a duly authorized committee thereof, as evidenced by a resolution of such Board or committee. 
  
 “GAAP” means generally accepted accounting principles set forth in the opinions and pronouncements of the Accounting Principles Board of
the American Institute of Certified Public Accountants and statements and pronouncements of the Financial Accounting Standards Board or in such other statements by such other entity as may be approved by a significant segment of the accounting
profession of the United States, as in effect from time to time. 
  
 “Guarantors” means (i) initially, each of: 
  
 Allegra, LLC, a California limited liability company; 
 APLAM, LLC, a California limited liability company; 
 AP LHI, Inc., a California corporation; 
 AP
Western GP Corporation, a Delaware corporation; 
 AP WP Operating Corporation, a Delaware corporation; 
 AP WP Partners, L.P., a Delaware limited partnership; 
 C. Richard Dobson Builders, Inc., a Virginia corporation; 
 CH Investments of Texas, Inc., a Delaware corporation; 
  

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 CHI Construction Company, an Arizona corporation; 
 CHTEX of Texas, Inc., a Delaware corporation; 
 The Club at Pradera, Inc., a Delaware corporation (formerly DRH Regrem II, Inc.); 
 Continental Homes, Inc., a Delaware corporation;

 Continental Homes of Texas, L.P., a Texas limited partnership; 
 Continental Residential, Inc., a California corporation; 
 D.R. Horton, Inc.-Birmingham, an Alabama corporation; 
 D.R. Horton, Inc.-Chicago, a Delaware corporation;

 D.R. Horton, Inc.-Denver, a Delaware corporation; 
 D.R. Horton, Inc.-Dietz-Crane, a Delaware corporation; 
 D.R. Horton, Inc.-Greensboro, a Delaware
corporation; 
 D.R. Horton, Inc.-Jacksonville, a Delaware corporation; 
 D.R. Horton, Inc.-Louisville, a Delaware corporation; 
 D.R. Horton, Inc.-Minnesota, a Delaware corporation; 
 D.R. Horton, Inc.-New Jersey, a Delaware corporation; 
 D.R. Horton, Inc.-Portland, a Delaware corporation; 
 D.R. Horton, Inc.-Sacramento, a California corporation; 
 D.R. Horton, Inc.-Torrey, a Delaware corporation; 
 D.R. Horton Los Angeles Holding Company, Inc., a California corporation; 
 D.R. Horton Management Company, Ltd., a Texas limited partnership; 
 D.R. Horton Materials, Inc., a Delaware
corporation (formerly DRH Regrem III, Inc.); 
 D.R. Horton San Diego Holding Company, Inc., a California corporation; 
 D.R. Horton-Emerald, Ltd., a Texas limited partnership; 
 D.R. Horton-Schuler Homes, LLC, a Delaware limited liability company; 
 D.R. Horton-Texas, Ltd., a Texas
limited partnership; 
 DRH Cambridge Homes, LLC, a Delaware limited liability company; 
 DRH Cambridge Homes, Inc., a California corporation; 
 DRH Construction, Inc., a Delaware corporation; 
 DRH Regrem IV, Inc., a Delaware corporation; 
 DRH Regrem V, Inc., a Delaware corporation; 
 DRH Regrem VII, LP, a Texas limited partnership; 
 DRH Regrem VIII, LLC, a Delaware limited liability company; 
 DRH Southwest Construction, Inc., a California corporation; 
 DRH Title Company of Colorado, Inc., a Colorado corporation; 
 DRH Tucson Construction, Inc., a Delaware
corporation; 
 DRHI, Inc., a Delaware corporation; 
 HPH Homebuilders 2000 L.P., a California limited partnership; 
 KDB Homes, Inc., a Delaware corporation;

  

 12 

 Lamco Housing, Inc., a California corporation; 
 Meadows I, Ltd., a Delaware corporation; 
 Meadows II, Ltd., a Delaware corporation; 
 Meadows VIII, Ltd., a Delaware corporation; 
 Meadows IX, Inc., a New Jersey corporation; 
 Meadows X, Inc., a New Jersey corporation; 
 Melody Homes, Inc., a Delaware corporation; 
 Melmort Co., a Colorado corporation; 
 Porter
GP LLC, a Delaware limited liability company; 
 Schuler Homes of Arizona, LLC, a Delaware limited liability company; 
 Schuler Homes of California, Inc., a California corporation; 
 Schuler Homes of Oregon, Inc., an Oregon corporation; 
 Schuler Homes of Washington, Inc., a Washington
corporation; 
 Schuler Mortgage, Inc., a Delaware corporation; 
 Schuler Realty Hawaii, Inc., a Hawaii corporation; 
 SGS Communities at Grande Quay, LLC, a New Jersey
limited liability company; 
 SHA Construction LLC, a Delaware limited liability company; 
 SHLR of California, Inc., a California corporation; 
 SHLR of Colorado, Inc., a Colorado corporation; 
 SHLR of Nevada, Inc., a Nevada corporation; 
 SHLR of Utah, Inc., a Utah corporation; 
 SHLR
of Washington, Inc., a Washington corporation; 
 SRHI LLC, a Delaware limited liability company; 
 SSHI LLC, a Delaware limited liability company; 
 Vertical Construction Corporation, a Delaware corporation; 
 Western Pacific Funding, Inc., a California corporation; 
 Western Pacific Housing, Inc., a Delaware corporation; 
 Western Pacific Housing Management, Inc., a California corporation; 
 Western Pacific Housing Co., a
California corporation; 
 Western Pacific Housing-Antigua, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Aviara, L.P., a California limited partnership; 
 Western Pacific Housing-Boardwalk, LLC, a Delaware limited liability company; 
 Western Pacific
Housing-Broadway, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Canyon Park, LLC, a Delaware limited liability
company; 
 Western Pacific Housing-Carmel, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Carrillo, LLC, a Delaware limited liability company; 
  

 13 

 Western Pacific Housing-Communications Hill, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Copper Canyon, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Creekside, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Culver City, L.P., a California limited partnership; 
 Western Pacific Housing-Del Valle, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Lomas
Verdes, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Lost Hills Park, LLC, a Delaware limited liability company;

 Western Pacific Housing-McGonigle Canyon, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Mountaingate, L.P., a California limited partnership; 
 Western Pacific Housing-Norco Estates, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Oso, L.P., a California limited partnership; 
 Western Pacific Housing-Pacific Park II, LLC, a Delaware limited liability company; 
 Western Pacific
Housing-Poinsettia, L.P., a California limited partnership; 
 Western Pacific Housing-Park Avenue East, LLC, a Delaware limited liability
company; 
 Western Pacific Housing-Park Avenue West, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Playa Vista, LLC, a Delaware limited liability company; 
 Western Pacific Housing-River Ridge, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Robinhood Ridge, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Santa Fe, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Scripps II, LLC, a Delaware limited liability company; 
 Western Pacific
Housing-Scripps, L.P., a California limited partnership; 
 Western Pacific Housing-Seacove, L.P., a California limited partnership;

 Western Pacific Housing-Studio 528, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Terra Bay Duets, LLC, a Delaware limited liability company; 
  

 14 

 Western Pacific Housing-Torrance, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Torrey Commercial, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Torrey Meadows, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Torrey Multi-Family, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Torrey Village Center, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Vineyard Terrace, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Windemere, LLC, a Delaware limited liability company; 
 Western Pacific Housing-Windflower, L.P., a California limited partnership; 
 WPH-Camino Ruiz, LLC, a Delaware limited liability company; 
 WPH-HPH, LLC, a Delaware limited liability
company; 
  
 and (ii) each of the Company’s Subsidiaries which becomes a
guarantor of the Notes pursuant to the provisions of the Indenture. An Unrestricted Subsidiary may become a Guarantor if it (x) is so designated by resolution of the Board of Directors of the Company and (y) executes a supplemental indenture
satisfactory to the Trustee. 
  
 “Holder” means
the Person in whose name a Note is registered in the books of the Registrar for the Notes. 
  
 “incurrence” has the meaning set forth in Section 3.02. 
  
 “Indebtedness” of any Person means, without duplication, (i) any liability of such Person (a) for borrowed money or under any
reimbursement obligation relating to a letter of credit or other similar instruments (other than standby letters of credit or similar instrument issued for the benefit of or surety, performance, completion or payment bonds, earnest money notes or
similar purpose undertakings or indemnifications issued by, such Person in the ordinary course of business), (b) evidenced by a bond, note, debenture or similar instrument (including a purchase money obligation) given in connection with the
acquisition of any businesses, properties or assets of any kind or with services incurred in connection with capital expenditures (other than any obligation to pay a contingent purchase price which, as of the date of incurrence thereof is not
required to be recorded as a liability in accordance with GAAP), or (c) in respect of Capitalized Lease Obligations (to the extent of the Attributable Debt in respect thereof), (ii) any Indebtedness of others that such Person has guaranteed to the
extent of the guarantee, (iii) to the extent not otherwise included, the obligations of such Per- 
  

 15 

 
son under Currency Agreements or Interest Protection Agreements to the extent recorded as liabilities not constituting Interest Incurred, net of amounts
recorded as assets in respect of such agreements, in accordance with GAAP, and (iv) all Indebtedness of others secured by a Lien on any asset of such Person, whether or not such Indebtedness is assumed by such Person; provided, that
Indebtedness shall not include accounts payable, liabilities to trade creditors of such Person or other accrued expenses arising in the ordinary course of business. The amount of Indebtedness of any Person at any date shall be (a) the outstanding
balance at such date of all unconditional obligations as described above, net of any unamortized discount to be accounted for as Interest Expense, in accordance with GAAP, (b) the maximum liability of such Person for any contingent obligations under
clause (ii) above at such date, net of, any unamortized discount to be accounted for as Interest Expense in accordance with GAAP and (c) in the case of clause (iv) above, the lesser of (1) the fair market value of any asset subject to a Lien
securing the Indebtedness of others on the date that the Lien attaches and (2) the amount of the Indebtedness secured. 
  
 “Indenture” has the meaning provided in the Recitals. 
  
 “Intangible Assets” of the Company means all unamortized debt discount and expense, unamortized deferred
charges, goodwill, patents, trademarks, service marks, trade names, copyrights, writeups of assets over their prior carrying value (other than write-ups which occurred prior to the Issue Date and other than, in connection with the acquisition of an
asset, the write-up of the value of such asset (within one year of its acquisition) to its fair market value in accordance with GAAP) and all other items which would be treated as intangibles on the consolidated balance sheet of the Company and the
Restricted Subsidiaries prepared in accordance with GAAP. 
  
 “Interest Expense” of any Person for any period means, without duplication, the aggregate amount of (i) interest which, in conformity with GAAP, would be set opposite the caption “interest expense” or any like
caption on an income statement for such Person (including, without limitation, imputed interest included in Capitalized Lease Obligations, all commissions, discounts and other fees and charges owed with respect to letters of credit and bankers’
acceptance financing, the net costs (but reduced by net gains) associated with Currency Agreements and Interest Protection Agreements, amortization of other financing fees and expenses, the interest portion of any deferred payment obligation,
amortization of discount or premium, if any, and all other noncash interest expense other than interest and other charges amortized to cost of sales), and (ii) all interest actually paid by the Company or a Restricted Subsidiary under any guarantee
of Indebtedness (including, without limitation, a guarantee of principal, interest or any combination thereof) of any Person other than the Company or any Restricted Subsidiary during such period; provided, that Interest Expense shall exclude

  

 16 

 
shall exclude any expense associated with the complete write-off of financing fees and expenses in connection with the repayment of any Indebtedness.

  
 “Interest Incurred” of any Person for any
period means, without duplication, the aggregate amount of (i) Interest Expense and (ii) all capitalized interest and amortized debt issuance costs. 
  
 “Interest Protection Agreement” of any Person means any interest rate swap agreement, interest rate collar agreement, option or futures
contract or other similar agreement or arrangement designed to protect such Person or any of its Subsidiaries against fluctuations in interest rates with respect to Indebtedness permitted to be incurred under this Supplemental Indenture. 

 
 “Investment Grade” shall mean BBB- or higher by S&P
or Baa3 or higher by Moody’s or the equivalent of such ratings by S&P or Moody’s. 
  
 “Investments” of any Person means (i) all investments by such Person in any other Person in the form of loans, advances or capital
contributions, (ii) all guarantees of Indebtedness or other obligations of any other Person by such Person, (iii) all purchases (or other acquisitions for consideration) by such Person of Indebtedness, Capital Stock or other securities of any other
Person and (iv) all other items that would be classified as investments in any other Person (including, without limitation, purchases of assets outside the ordinary course of business) on a balance sheet of such Person prepared in accordance with
GAAP. 
  
 “Issue Date” means the date on which
the Notes are originally issued under this Supplemental Indenture. 
  
 “Lien” means, with respect to any Property, any mortgage, lien, pledge, charge, security interest or encumbrance of any kind in respect of such Property. For purposes of this definition, a Person shall be deemed to own,
subject to a Lien, any Property which it has acquired or holds subject to the interest of a vendor or lessor under any conditional sale agreement, capital lease or other title retention agreement relating to such Property. 
  
 “Marketable Securities” means (a) equity securities that are
listed on the New York Stock Exchange, the American Stock Exchange or The Nasdaq National Market and (b) debt securities that are rated by a nationally recognized rating agency, listed on the New York Stock Exchange or the American Stock Exchange or
covered by at least two reputable market makers. 
  
 “Moody’s” means Moody’s Investors Service, Inc. or any successor to its debt rating business. 
  

 17 

 “Mortgage Subsidiary” means any Subsidiary of the Company substantially all of whose
operations consist of the mortgage lending business. 
  
 “Net Cash Proceeds” means, with respect to an Asset Disposition, cash payments received (including any cash payments received by way of deferred payment of principal pursuant to a note or installment receivable or otherwise
(including any cash received upon sale or disposition of such note or receivable), but only as and when received), excluding any other consideration received in the form of assumption by the acquiring Person of Indebtedness or other obligations
relating to the Property disposed of in such Asset Disposition or received in any other non-cash form unless and until such non-cash consideration is converted into cash therefrom, in each case, net of all legal, title and recording tax expenses,
commissions and other fees and expenses incurred, and all federal, state and local taxes required to be accrued as a liability under GAAP as a consequence of such Asset Disposition, and in each case net of a reasonable reserve for the after-tax cost
of any indemnification or other payments (fixed and contingent) attributable to the seller’s indemnities or other obligations to the purchaser undertaken by the Company or any of its Restricted Subsidiaries in connection with such Asset
Disposition, and net of all payments made on any Indebtedness which is secured by or relates to such Property, in accordance with the terms of any Lien or agreement upon or with respect to such Property or which must by its terms or by applicable
law be repaid out of the proceeds from such Asset Disposition, and net of all contractually required distributions and payments made to minority interest holders in Restricted Subsidiaries or joint ventures as a result of such Asset Disposition.

  
 “Non-Recourse Indebtedness” with respect to
any Person means Indebtedness of such Person for which (i) the sole legal recourse for collection of principal and interest on such Indebtedness is against the specific property identified in the instruments evidencing or securing such Indebtedness
and such property was acquired with the proceeds of such Indebtedness or such Indebtedness was incurred within 90 days after the acquisition of such property and (ii) no other assets of such Person may be realized upon in collection of principal or
interest on such Indebtedness. Indebtedness which is otherwise Non-Recourse Indebtedness will not lose its character as Non-Recourse Indebtedness because there is recourse to the borrower, any guarantor or any other Person for (i) environmental
warranties and indemnities, or (ii) indemnities for and liabilities arising from fraud, misrepresentation, misapplication or non-payment of rents, profits, insurance and condemnation proceeds and other sums actually received by the borrower from
secured assets to be paid to the lender, waste and mechanics’ liens. 
  
 “Notes” has the meaning provided in the Recitals. 
  
 “Paying Agent” means the Trustee or any successor paying agent. 
  

 18 

 “Permitted Indebtedness” means (i) Indebtedness under Credit Facilities which does not
exceed $1.0 billion principal amount outstanding at any one time; (ii) Indebtedness in respect of obligations of the Company and its Subsidiaries to the trustees under indentures for debt securities; (iii) intercompany debt obligations of the
Company to any Restricted Subsidiary and of any Restricted Subsidiary to the Company or any other Restricted Subsidiary; provided, however, that any Indebtedness of any Restricted Subsidiary or the Company owed to any Restricted
Subsidiary or that ceases to be a Restricted Subsidiary shall be deemed to be incurred and shall be treated as an incurrence for purposes of the first paragraph of the covenant described under “Limitations on Indebtedness” at the time the
Restricted Subsidiary in question ceases to be a Restricted Subsidiary; (iv) Indebtedness of the Company or any Restricted Subsidiary under any Currency Agreements or Interest Protection Agreements in a notional amount no greater than the payments
due (at the time the related Currency Agreement or Interest Protection Agreement is entered into) with respect to the Indebtedness or currency being hedged; (v) Purchase Money Indebtedness; (vi) Capitalized Lease Obligations; (vii) obligations for,
pledge of assets in respect of, and guaranties of, bond financings of political subdivisions or enterprises thereof in the ordinary course of business; (viii) Indebtedness secured only by office buildings owned or occupied by the Company or any
Restricted Subsidiary, which Indebtedness does not exceed $20 million aggregate principal amount outstanding at any one time; (ix) Indebtedness under warehouse lines of credit, repurchase agreements and Indebtedness secured by mortgage loans and
related assets of mortgage lending Subsidiaries in the ordinary course of a mortgage lending business; and (x) Indebtedness of the Company or any Restricted Subsidiary which, together with all other Indebtedness under this clause (x), does not
exceed $30 million aggregate principal amount outstanding at any one time. 
  
 “Permitted Investment” means (i) Cash Equivalents; (ii) any Investment in the Company or any Restricted Subsidiary or any Person that becomes a Restricted Subsidiary as a result of such Investment or
that is consolidated or merged with or into, or transfers all or substantially all of the assets of it or an operating unit or line of business to, the Company or a Restricted Subsidiary; (iii) any receivables, loans or other consideration taken by
the Company or any Restricted Subsidiary in connection with any asset sale otherwise permitted by the Indenture; (iv) Investments received in connection with any bankruptcy or reorganization proceeding, or as a result of foreclosure, perfection or
enforcement of any Lien or any judgment or settlement of any Person in exchange for or satisfaction of Indebtedness or other obligations or other property received from such Person, or for other liabilities or obligations of such Person created, in
accordance with the terms of the Indenture; (v) Investments in Currency Agreements or Interest Protection Agreements described in the definition of Permitted Indebtedness; (vi) any loan or advance to an executive officer or director of the Company
or any Restricted Subsidiary made in the ordinary course of business; provided, however, that any such loan or advance exceeding $1 million shall have been approved by the Board of Di- 

  

 19 

 
rectors of the Company or a committee thereof consisting of disinterested members; (vii) Investments in joint ventures in a Real Estate Business with
unaffiliated third parties in an aggregate amount at any time outstanding not to exceed 10% of Consolidated Tangible Assets at such time; (viii) Investments in interests in issuances of collateralized mortgage obligations, mortgages, mortgage loan
securities or other mortgage related assets; and (ix) Investments in an aggregate amount outstanding not to exceed $100 million. 
  
 “Permitted Liens” means (i) Liens for taxes, assessments or governmental or quasi-government charges or claims that (a) are not yet
delinquent, (b) are being contested in good faith by appropriate proceedings and as to which appropriate reserves have been established or other provisions have been made in accordance with GAAP, if required, or (c) encumber solely property
abandoned or in the process of being abandoned, (ii) statutory Liens of landlords and carriers’, warehousemen’s, mechanics’, suppliers’, materialmen’s, repairmen’s or other Liens imposed by law and arising in the
ordinary course of business and with respect to amounts that, to the extent applicable, either (a) are not yet delinquent or (b) are being contested in good faith by appropriate proceedings and as to which appropriate reserves have been established
or other provisions have been made in accordance with GAAP, if required, (iii) Liens (other than any Lien imposed by the Employee Retirement Income Security Act of 1974, as amended) incurred or deposits made in the ordinary course of business in
connection with workers’ compensation, unemployment insurance and other types of social security, (iv) Liens incurred or deposits made to secure the performance of tenders, bids, leases, statutory obligations, surety and appeal bonds,
development obligations, progress payments, government contacts, utility services, developer’s or other obligations to make on-site or off-site improvements and other obligations of like nature (exclusive of obligations for the payment of
borrowed money but including the items referred to in the parenthetical in clause (i)(a) of the definition of “Indebtedness”), in each case incurred in the ordinary course of business of the Company and the Restricted Subsidiaries, (v)
attachment or judgment Liens not giving rise to a Default or an Event of Default, (vi) easements, dedications, assessment district or similar liens in connection with municipal or special district financing, rights-of-way, restrictions,
reservations, other similar charges, burdens, and other similar charges or encumbrances not materially interfering with the ordinary course of business of the Company and the Restricted Subsidiaries, (vii) zoning restrictions, licenses, restrictions
on the use of real property or minor irregularities in title thereto, which do not materially impair the use of such real property in the ordinary course of business of the Company and the Restricted Subsidiaries, (viii) Liens securing Indebtedness
incurred pursuant to clause (viii) or (ix) of the definition of Permitted Indebtedness, (ix) Liens securing Indebtedness of the Company or any Restricted Subsidiary permitted to be incurred under the Indenture; provided, that the aggregate
amount of all consolidated Indebtedness of the Company and the Restricted Subsidiaries (including, with respect to Capitalized Lease Obligations, the Attributable Debt in respect thereof) secured by Liens (other than Non-Recourse Indebtedness and
Indebtedness incurred 

  

 20 

 
pursuant to clause (ix) of the definition of Permitted Indebtedness) shall not exceed 40% of Consolidated Adjusted Tangible Assets at any one time
outstanding (after giving effect to the incurrence of such Indebtedness and the use of the proceeds thereof), (x) Liens securing Non-Recourse Indebtedness of the Company or any Restricted Subsidiary; provided, that such Liens apply only to
the property financed out of the net proceeds of such Non-Recourse Indebtedness within 90 days after the incurrence of such Non-Recourse Indebtedness, (xi) Liens securing Purchase Money Indebtedness; provided that such Liens apply only to the
property acquired, constructed or improved with the proceeds of such Purchase Money Indebtedness within 90 days after the incurrence of such Purchase Money Indebtedness, (xii) Liens on property or assets of the Company or any Restricted Subsidiary
securing Indebtedness of the Company or any Restricted Subsidiary owing to the Company or one or more Restricted Subsidiaries, (xiii) leases or subleases granted to others not materially interfering with the ordinary course of business of the
Company and the Restricted Subsidiaries, (xiv) purchase money security interests (including, without limitation, Capitalized Lease Obligations); provided, that such Liens apply only to the Property acquired and the related Indebtedness is
incurred within 90 days after the acquisition of such Property, (xv) any right of first refusal, right of first offer, option, contract or other agreement to sell an asset; provided, that such sale is not otherwise prohibited under the
Indenture, (xvi) any right of a lender or lenders to which the Company or a Restricted Subsidiary may be indebted to offset against, or appropriate and apply to the payment of such, Indebtedness any and all balances, credits, deposits, accounts or
money of the Company or a Restricted Subsidiary with or held by such lender or lenders or its Affiliates, (xvii) any pledge or deposit of cash or property in conjunction with obtaining surety, performance, completion or payment bonds and letters of
credit or other similar instruments or providing earnest money obligations, escrows or similar purpose undertakings or indemnifications in the ordinary course of business of the Company and its Restricted Subsidiaries, (xviii) Liens for homeowner
and property owner association developments and assessments, (xix) Liens securing Refinancing Indebtedness; provided, that such Liens extend only to the assets securing the Indebtedness being refinanced, and (xx) Liens incurred in the
ordinary course of business as security for the obligations of the Company and its Restricted Subsidiaries with respect to indemnification in respect of title insurance providers. 
  
 “Person” means any individual, corporation, partnership, limited liability company, joint venture,
incorporated or unincorporated association, joint stock company, trust, unincorporated organization or government or any agency or political subdivision thereof. 
  
 “Preferred Stock” of any Person means all Capital Stock of such Person which has a preference in
liquidation or with respect to the payment of dividends. 
  

 21 

 “Property” of any Person means all types of real, personal, tangible, intangible or
mixed property owned by such Person, whether or not included in the most recent consolidated balance sheet of such Person and its Subsidiaries under GAAP. 
  
 “Public Equity Offering” means an underwritten public offering of Common Equity of the Company pursuant to an effective registration
statement filed under the Securities Act (excluding registration statements filed on Form S-8 or any successor form). 
  
 “Purchase Money Indebtedness” means Indebtedness of the Company or any Restricted Subsidiary incurred for the purpose of financing all or
any part of the purchase price, or the cost of construction or improvement, of any property to be used in the ordinary course of business by the Company and the Restricted Subsidiaries; provided, however, that (i) the aggregate
principal amount of such Indebtedness shall not exceed such purchase price or cost and (ii) such Indebtedness shall be incurred no later than 90 days after the acquisition of such property or completion of such construction or improvement.

  
 “Qualified Stock” means Capital Stock of the
Company other than Disqualified Stock. 
  
 “Rating
Agencies” shall mean (1) S&P and (2) Moody’s. 
  
 “Real Estate Business” means homebuilding, housing construction, real estate development or construction and related real estate activities, including the provision of mortgage financing or title insurance. 
  
 “Refinancing Indebtedness” means Indebtedness (to the extent
not Permitted Indebtedness) that refunds, refinances or extends any Indebtedness of the Company or any Restricted Subsidiary (to the extent not Permitted Indebtedness) outstanding on the Issue Date or other Indebtedness (to the extent not Permitted
Indebtedness) permitted to be incurred by the Company or any Restricted Subsidiary pursuant to the terms of this Indenture, but only to the extent that (i) the Refinancing Indebtedness is subordinated to the Notes or the Guarantees, as the case may
be, to the same extent as the Indebtedness being refunded, refinanced or extended, if at all, (ii) the Refinancing Indebtedness is scheduled to mature either (a) no earlier than the Indebtedness being refunded, refinanced or extended or (b) after
the maturity date of the Notes, (iii) the portion, if any, of the Refinancing Indebtedness that is scheduled to mature on or prior to the maturity date of the Notes has a Weighted Average Life to Maturity at the time such Refinancing Indebtedness is
incurred that is equal to or greater than the Weighted Average Life to Maturity of the portion of the Indebtedness being refunded, refinanced or extended that is scheduled to mature on or prior to the maturity date of the Notes, and (iv) such
Refinancing Indebtedness is in an aggregate principal amount that is equal to or 

  

 22 

 
less than the aggregate principal amount then outstanding under the Indebtedness being refunded, refinanced or extended. 
  
 “Registrar” means American Stock Transfer & Trust
Company or any successor registrar of the Notes. 
  
 “Restricted Payment” means any of the following: (i) the declaration or payment of any dividend or any other distribution on Capital Stock of the Company or any Restricted Subsidiary or any payment made to the direct or
indirect holders (in their capacities as such) of Capital Stock of the Company or any Restricted Subsidiary (other than (a) dividends or distributions payable solely in Qualified Stock and (b) in the case of Restricted Subsidiaries, dividends or
distributions payable to the Company or to a Restricted Subsidiary); (ii) the purchase, redemption or other acquisition or retirement for value of any Capital Stock of the Company or any Restricted Subsidiary (other than a payment made to the
Company or any Restricted Subsidiary); and (iii) any Investment (other than any Permitted Investment), including any Investment in an Unrestricted Subsidiary (including by the designation of a Subsidiary of the Company as an Unrestricted
Subsidiary). 
  
 “Restricted Subsidiary” means
any Subsidiary of the Company which is not an Unrestricted Subsidiary. 
  
 “S&P” means Standard and Poor’s Ratings Group or any successor to its debt rating business. 
  
 “Significant Subsidiary” means any Subsidiary of the Company which would constitute a “significant subsidiary” as defined in
Rule 1-02 of Regulation S-X under the Securities Act and the Exchange Act. 
  
 “Subsidiary” of any Person means any corporation or other entity of which a majority of the Capital Stock having ordinary voting power to elect a majority of the Board of Directors or other persons
performing similar functions is at the time directly or indirectly owned or controlled by such Person. 
  
 “Successor” has the meaning set forth in Section 3.08. 
  
 “Supplemental Indenture” has the meaning provided in the Preamble. 
  
 “Trustee” means the party named as such above until a
successor replaces such party in accordance with the applicable provisions of this Indenture and thereafter means the successor serving hereunder. 
  

 23 

 “Unrestricted Subsidiary” means any Subsidiary of the Company so designated by a
resolution adopted by the Board of Directors of the Company or a duly authorized committee thereof as provided below; provided that (a) the holders of Indebtedness thereof do not have direct or indirect recourse against the Company or any
Restricted Subsidiary, and neither the Company nor any Restricted Subsidiary otherwise has liability, for any payment obligations in respect of such Indebtedness (including any undertaking, agreement or instrument evidencing such Indebtedness),
except, (i) in each case, to the extent that the amount thereof constitutes a Restricted Payment permitted by the Indenture, (ii) in the case of Non-Recourse Indebtedness, to the extent such recourse or liability is for the matters discussed in the
last sentence of the definition of “Non-Recourse Indebtedness,” or (iii) to the extent such Indebtedness is a guarantee by such Subsidiary of Indebtedness of the Company or a Restricted Subsidiary and (b) no holder of any Indebtedness of
such Subsidiary shall have a right to declare a default on such Indebtedness or cause the payment thereof to be accelerated or payable prior to its stated maturity as a result of a default on any Indebtedness of the Company or any Restricted
Subsidiary. Subject to the foregoing, the Board of Directors of the Company or a duly authorized committee thereof may designate any Subsidiary to be an Unrestricted Subsidiary; provided, however, that (i) the net amount (the
“Designation Amount”) then outstanding of all previous Investments by the Company and the Restricted Subsidiaries in such Subsidiary will be deemed to be a Restricted Payment at the time of such designation and will reduce the
amount available for Restricted Payments under Section 3.03 hereof, to the extent provided therein, (ii) the Company must be permitted under Section 3.03 hereof to make the Restricted Payment deemed to have been made pursuant to clause (i), and
(iii) after giving effect to such designation, no Default or Event of Default shall have occurred and be continuing. In accordance with the foregoing, and not in limitation thereof, Investments made by any Person in any Subsidiary of such Person
prior to such Person’s merger with the Company or any Restricted Subsidiary (but not in contemplation or anticipation of such merger) shall not be counted as an Investment by the Company or such Restricted Subsidiary if such Subsidiary of such
Person is designated as an Unrestricted Subsidiary. The Board of Directors of the Company or a duly authorized committee thereof may also redesignate an Unrestricted Subsidiary to be a Restricted Subsidiary; provided, however, that (i)
the Indebtedness of such Unrestricted Subsidiary as of the date of such redesignation could then be incurred under Section 3.02 hereof and (ii) immediately after giving effect to such redesignation and the incurrence of any such additional
Indebtedness, the Company and the Restricted Subsidiaries could incur $1.00 of additional Indebtedness under Section 3.02(a) hereof. Any such designation or redesignation by the Board of Directors of the Company or a committee thereof will be
evidenced to the Trustee by the filing with the Trustee of a certified copy of the resolution of the Board of Directors of the Company or a committee thereof giving effect to such designation or redesignation and an Officers’ Certificate
certifying that such designation or redesignation complied with the foregoing conditions and setting forth the underlying calculations of such Officers’ Certificate. The designation of any Person as an Unrestricted Subsidiary shall be 

  

 24 

 
deemed to include a designation of all Subsidiaries of such Person as Unrestricted Subsidiaries; provided, however, that the ownership of the
general partnership interest (or a similar member’s interest in a limited liability company) by an Unrestricted Subsidiary shall not cause a Subsidiary of the Company of which more than 95% of the equity interest is held by the Company or one
or more Restricted Subsidiaries to be deemed an Unrestricted Subsidiary. 
  
 “Weighted Average Life to Maturity” means, when applied to any Indebtedness or portion thereof at any date, the number of years obtained by dividing (i) the sum of the products obtained by multiplying
(a) the amount of each then remaining installment, sinking fund, serial maturity or other required payment of principal, including, without limitation, payment at final maturity, in respect thereof, by (b) the number of years (calculated to the
nearest one-twelfth) that will elapse between such date and the making of such payment by (ii) the sum of all such payments described in clause (i)(a) above. 
  
 ARTICLE THREE 
  
 Covenants 
  
 Section
3.01. Repurchase of Notes upon Change of Control. 
  
 (a)
In the event that there shall occur a Change of Control, each Holder of Notes shall have the right, at such Holder’s option, to require the Company to purchase all or any part of such Holder’s Notes on a date (the “Repurchase
Date”) that is no later than 90 days after notice of the Change of Control, at 101% of the principal amount thereof plus accrued interest to the Repurchase Date. 
  
 (b) On or before the thirtieth day after any Change of Control, the Company is obligated to mail, or cause to be mailed, to
all Holders of record of Notes a notice regarding the Change of Control and the repurchase right. The notice shall state the Repurchase Date, the date by which the repurchase right must be exercised, the price for the Notes and the procedure which
the Holder must follow to exercise such right. Substantially simultaneously with mailing of the notice, the Company shall cause a copy of such notice to be published in a newspaper of general circulation in the Borough of Manhattan, The City of New
York. To exercise such right, the Holder of such Note must deliver at least ten days prior to the Repurchase Date written notice to the Company (or an agent designated by the Company for such purpose) of the Holder’s exercise of such right,
together with the Note with respect to which the right is being exercised, duly endorsed for transfer; provided, however, that if mandated by applicable law, a Holder may be permitted to deliver such written notice nearer to the
Repurchase Date than may be specified by the Company. 
  

 25 

 (c) The Company will comply with applicable law, including Section 14(e) of the Exchange Act and Rule
14e-1 thereunder, if applicable, if the Company is required to give a notice of right of repurchase as a result of a Change of Control. 
  
 Section 3.02. Limitations on Indebtedness. 
  
 (a) Until the Notes are rated Investment Grade by both Rating Agencies (after which time the following covenant will no longer be in effect), the Company
will not, and will not cause or permit any Restricted Subsidiary, directly or indirectly, to, create, incur, assume, become liable for or guarantee the payment of (collectively, an “incurrence”) any Indebtedness (including Acquired
Indebtedness) unless, after giving effect thereto and the application of the proceeds therefrom, the Consolidated Fixed Charge Coverage Ratio on the date thereof would be at least 2.0 to 1.0. 
  
 (b) Notwithstanding the foregoing, the provisions of this Supplemental
Indenture will not prevent the incurrence of: (i) Permitted Indebtedness, (ii) Refinancing Indebtedness, (iii) Non-Recourse Indebtedness, (iv) any Guarantee of Indebtedness of the Company represented by the Notes and (v) any guarantee of
Indebtedness incurred under Credit Facilities in compliance with this Indenture. 
  
 (c) For purposes of determining compliance with this covenant, in the event that an item of Indebtedness may be incurred through the first paragraph of this covenant or by meeting the criteria of one or more of the
types of Indebtedness described in the second paragraph of this covenant (or the definitions of the terms used therein), the Company, in its sole discretion, (i) may classify such item of Indebtedness under and comply with either of such paragraphs
(or any of such definitions), as applicable, (ii) may classify and divide such item of Indebtedness into more than one of such paragraphs (or definitions), as applicable, and (iii) may elect to comply with such paragraphs (or definitions), as
applicable, in any order. 
  
 (d) The Company will not, and will
not cause or permit any Guarantor to, directly or indirectly, in any event incur any Indebtedness that purports to be by its terms (or by the terms of any agreement governing such Indebtedness) subordinated to any other Indebtedness of the Company
or of such Guarantor, as the case may be, unless such Indebtedness is also by its terms (or by the terms of any agreement governing such Indebtedness) made expressly subordinated to the Notes or the Guarantee of such Guarantor, as the case may be,
to the same extent and in the same manner as such Indebtedness is subordinated to such other Indebtedness of the Company or such Guarantor, as the case may be. 
  

 26 

 Section 3.03. Limitations on Restricted Payments. 
  
 (a) Until the Notes are rated Investment Grade by both Rating Agencies (after which time the following covenant will no
longer be in effect), the Company will not, and will not cause or permit any Restricted Subsidiary to, directly or indirectly, make any Restricted Payment unless: 
  
 (i) no Default or Event of Default shall have occurred and be continuing at the time of or immediately after
giving effect to such Restricted Payment; 
  
 (ii) immediately after giving effect to such Restricted Payment, the Company could incur at least $1.00 of Indebtedness pursuant to Section 3.02(a) hereof; and 
  
 (iii) immediately after giving effect to such Restricted Payment, the aggregate amount of all Restricted
Payments (including the Fair Market Value of any non-cash Restricted Payment) declared or made after the Issue Date does not exceed the sum of (a) 50% of the Consolidated Net Income of the Company on a cumulative basis during the period (taken as
one accounting period) from and including April 1, 1998 and ending on the last day of the Company’s fiscal quarter immediately preceding the date of such Restricted Payment (or in the event such Consolidated Net Income shall be a deficit, minus
100% of such deficit), plus (b) 100% of the aggregate net cash proceeds of and the fair market value of Property received by the Company from (1) any capital contribution to the Company after June 9, 1997 or any issue or sale after June 9,
1997 of Qualified Stock (other than to any Subsidiary of the Company) and (2) the issue or sale after June 9, 1997 of any Indebtedness or other securities of the Company convertible into or exercisable for Qualified Stock of the Company that have
been so converted or exercised, as the case may be, plus (c) $86.0 million, which is equal to the aggregate principal amount of the Company’s 6-7/8% Convertible Subordinated Notes due 2002 that were converted into the Company’s
Common Equity prior to the Issue Date, plus (d) in the case of the disposition or repayment of any Investment constituting a Restricted Payment made after the June 9, 1997, an amount (to the extent not included in the calculation of the Consolidated
Net Income referred to in (a)) equal to the lesser of (x) the return of capital with respect to such Investment (including by dividend, distribution or sale of Capital Stock) and (y) the amount of such Investment that was treated as a Restricted
Payment, in either case, less the cost of the disposition or repayment of such Investment (to the extent not included in the calculation of the Consolidated Net Income referred to in (a)), plus (e) with respect to any Unrestricted Subsidiary
that is redesignated as a Restricted Subsidiary after June 9, 1997 in accordance with the definition of Unrestricted Subsidiary (so long as the designation of such Subsidiary as an Unrestricted Subsidiary was treated as a Restricted Payment 

  

 27 

 
made after June 9, 1997 and only to the extent not included in the calculation of the Consolidated Net Income referred to in (a)), an amount equal to the
lesser of (x) the proportionate interest of the Company or a Restricted Subsidiary in an amount equal to the excess of (I) the total assets of such Subsidiary, valued on an aggregate basis at the lesser of book value and Fair Market Value thereof,
over (II) the total liabilities of such Subsidiary, determined in accordance with GAAP, and (y) the Designation Amount at the time of such Subsidiary’s designation as an Unrestricted Subsidiary, plus (f) $50 million minus (g) the
aggregate amount of all Restricted Payments (other than Restricted Payments referred to in clause (C) of the immediately succeeding paragraph) made after June 9, 1997 through the Issue Date. 
  
 (b) Clauses (ii) and (iii) of paragraph (a) will not prohibit: (A) the
payment of any dividend within 60 days of its declaration if such dividend could have been made on the date of its declaration without violation of the provisions of this Indenture; (B) the repurchase, redemption or retirement of any shares of
Capital Stock of the Company in exchange for, or out of the net proceeds of the substantially concurrent sale (other than to a Subsidiary of the Company) of, other shares of Qualified Stock; and (C) the purchase, redemption or other acquisition,
cancellation or retirement for value of Capital Stock, or options, warrants, equity appreciation rights or other rights to purchase or acquire Capital Stock, of the Company or any Subsidiary held by officers or employees or former officers or
employees of the Company or any Subsidiary (or their estates or beneficiaries under their estates) not to exceed $20 million in the aggregate since the Issue Date; provided, however, that each Restricted Payment described in clauses
(A) and (B) of this sentence shall be taken into account for purposes of computing the aggregate amount of all Restricted Payments pursuant to clause (iii) of paragraph (a). 
  
 (c) For purposes of determining the aggregate and permitted amounts of Restricted Payments made, the amount of any guarantee
of any Investment in any Person that was initially treated as a Restricted Payment and which was subsequently terminated or expired, net of any amounts paid by the Company or any Restricted Subsidiary in respect of such guarantee, shall be deducted.

  
 (d) In determining the “fair market value of
Property” for purposes of clause (iii) of the paragraph (a), Property other than cash, Cash Equivalents and Marketable Securities shall be deemed to be equal in value to the “equity value” of the Capital Stock or other securities
issued in exchange therefor. The “equity value” of such Capital Stock or other securities shall be equal to (i) the number of shares of Common Equity issued in the transaction (or issuable upon conversion or exercise of the Capital Stock
or other securities issued in the transaction) multiplied by the closing sale price of the Common Equity on its principal market on the date of the transaction (less, in the case of Capital Stock or other secu- 

  

 28 

 
rities which require the payment of consideration at the time of conversion or exercise, the aggregate consideration payable thereupon) or (ii) if the Common
Equity is not then traded on the New York Stock Exchange, American Stock Exchange or Nasdaq National Market, or if the Capital Stock or other securities issued in the transaction do not consist of Common Equity (or Capital Stock or other securities
convertible into or exercisable for Common Equity), the value of such Capital Stock or other securities as determined by a nationally recognized investment banking firm retained by the Board of Directors of the Company. 
  
 Section 3.04. Limitations on Transactions with Affiliates. 
  
 (a) Until the Notes are rated Investment Grade by both Rating Agencies
(after which time the following covenant will no longer be in effect), the Company will not, and will not cause or permit any Restricted Subsidiary to, make any loan, advance, guarantee or capital contribution to, or for the benefit of, or sell,
lease, transfer or otherwise dispose of any property or assets to, or for the benefit of, or purchase or lease any property or assets from, or enter into or amend any contract, agreement or understanding with, or for the benefit of, any Affiliate of
the Company or any Affiliate of any of the Company’s Subsidiaries or any holder of 10% or more of the Common Equity of the Company (including any Affiliates of such holders), in a single transaction or series of related transactions (each, an
“Affiliate Transaction”), except for any Affiliate Transaction the terms of which are at least as favorable as the terms which could be obtained by the Company or such Restricted Subsidiary, as the case may be, in a comparable
transaction made on an arm’s length basis with Persons who are not such a holder, an Affiliate of such a holder or an Affiliate of the Company or any of the Company’s Subsidiaries. 
  
 (b) In addition, the Company will not, and will not cause or permit any
Restricted Subsidiary to, enter into an Affiliate Transaction unless (i) with respect to any such Affiliate Transaction involving or having a value of more than $10 million, the Company shall have (x) obtained the approval of a majority of the Board
of Directors of the Company and (y) either obtained the approval of a majority of the Company’s disinterested directors or obtained an opinion of a qualified independent financial advisor to the effect that such Affiliate Transaction is fair to
the Company or such Restricted Subsidiary, as the case may be, from a financial point of view and (ii) with respect to any such Affiliate Transaction involving or having a value of more than $50 million, the Company shall have (x) obtained the
approval of a majority of the Board of Directors of the Company and (y) delivered to the Trustee an opinion of a qualified independent financial advisor to the effect that such Affiliate Transaction is fair to the Company or such Restricted
Subsidiary, as the case may be, from a financial point of view. 
  

 29 

 (c) Notwithstanding the foregoing, an Affiliate Transaction will not include (i) any contract, agreement
or understanding with, or for the benefit of, or plan for the benefit of employees of the Company or its Subsidiaries generally (in their capacities as such) that has been approved by the Board of Directors of the Company, (ii) Capital Stock
issuances to directors, officers and employees of the Company or its Subsidiaries pursuant to plans approved by the stockholders of the Company, (iii) any Restricted Payment otherwise permitted under Section 3.03, (iv) any transaction between or
among the Company and one or more Restricted Subsidiaries or between or among Restricted Subsidiaries (provided, however, no such transaction shall involve any other Affiliate of the Company (other than an Unrestricted Subsidiary to
the extent the applicable amount constitutes a Restricted Payment permitted by this Indenture)) and (v) any transaction between one or more Restricted Subsidiaries and one or more Unrestricted Subsidiaries where all of the payments to, or other
benefits conferred upon, such Unrestricted Subsidiaries are substantially contemporaneously dividended, or otherwise distributed or transferred without charge, to the Company or a Restricted Subsidiary. 
  
 Section 3.05. Limitations on Dispositions of Assets. 
  
 Until the Notes are rated Investment Grade by both Rating Agencies (after
which time the following covenant will no longer be in effect), the Company will not, and will not cause or permit any Restricted Subsidiary to, make any Asset Disposition unless (x) the Company (or such Restricted Subsidiary, as the case may be)
receives consideration at the time of such Asset Disposition at least equal to the Fair Market Value thereof, and (y) not less than 70% of the consideration received by the Company (or such Restricted Subsidiary, as the case may be) is in the form
of cash, Cash Equivalents and Marketable Securities. The amount of any Indebtedness (other than any Indebtedness subordinated to the Notes) of the Company or any Restricted Subsidiary that is actually assumed by the transferee in such Asset
Disposition shall be deemed to be consideration required by clause (y) above for purposes of determining the percentage of such consideration received by the Company or the Restricted Subsidiaries. The Net Cash Proceeds of an Asset Disposition
shall, within one year, at the Company’s election, (a) be used by the Company or a Restricted Subsidiary in the business of the construction and sale of homes conducted by the Company and the Restricted Subsidiaries or any other business of the
Company or a Restricted Subsidiary existing at the time of such Asset Disposition or (b) to the extent not so used, be applied to make a Net Cash Proceeds Offer for the Notes and, if the Company or a Restricted Subsidiary elects or is required to do
so, repay, purchase or redeem any other unsubordinated Indebtedness (on a pro rata basis if the amount available for such repayment, purchase or redemption is less than the aggregate amount of (i) the principal amount of the Notes tendered in such
Net Cash Proceeds Offer and (ii) the lesser of the principal amount, or accreted value, of such other unsubordinated Indebtedness, plus, in each case accrued interest to the date of repayment, purchase or redemption) at 100% of the principal amount
or accreted value thereof, as the case may be, plus accrued 

  

 30 

 
interest to the date of repurchase or repayment. Notwithstanding the foregoing, (A) the Company will not be required to apply such Net Cash Proceeds to the
repurchase of Notes in accordance with clause (b) of the preceding sentence except to the extent that such Net Cash Proceeds, together with the aggregate Net Cash Proceeds of prior Asset Dispositions (other than those so used) which have not been
applied in accordance with this provision and as to which no prior Net Cash Proceeds Offer shall have been made, exceed 5% of Consolidated Tangible Assets and (B) in connection with any Asset Disposition, the Company and the Restricted Subsidiaries
will not be required to comply with the requirements of clause (y) of the first sentence of this paragraph to the extent that the aggregate non-cash consideration received in connection with such Asset Disposition, together with the sum of all
non-cash consideration received in connection with all prior Asset Dispositions that has not yet been converted into cash, does not exceed 5% of Consolidated Tangible Assets; provided, however, that when any non-cash consideration is
converted into cash, such cash shall constitute Net Cash Proceeds and be subject to the preceding sentence. 
  
 Section 3.06. Limitations on Liens. 
  
 The Company will not, and will not cause or permit any Restricted Subsidiary to, create, incur, assume or suffer to exist any Liens, other than Permitted Liens, on any of its Property, or on any shares of Capital
Stock or Indebtedness of any Restricted Subsidiary, unless contemporaneously therewith or prior thereto all payments due under this Indenture and the Notes are secured on an equal and ratable basis with the obligation or liability so secured until
such time as such obligation or liability is no longer secured by a Lien. 
  
 Section 3.07. Limitations on Restrictions Affecting Restricted Subsidiaries. 
  
 The Company will not, and will not cause or permit any Restricted Subsidiary to, create, assume or otherwise cause or suffer to exist or become effective any consensual encumbrance or restriction (other than
encumbrances or restrictions imposed by law or by judicial or regulatory action or by provisions of leases and other agreements that restrict the assignability thereof) on the ability of any Restricted Subsidiary to (i) pay dividends or make any
other distributions on its Capital Stock or any other interest or participation in, or measured by, its profits, owned by the Company or any other Restricted Subsidiary, or pay interest on or principal of any Indebtedness owed to the Company or any
other Restricted Subsidiary, (ii) make loans or advances to the Company or any other Restricted Subsidiary, or (iii) transfer any of its properties or assets to the Company or any other Restricted Subsidiary, except for (a) encumbrances or
restrictions existing under or by reason of applicable law, (b) covenants or restrictions contained in Indebtedness in effect on the Issue Date as such covenants or restrictions are in effect on such date, (c) any restrictions or encumbrances
arising under Acquired Indebtedness; provided, that such encumbrance or restriction applies only to either the 

  

 31 

 
assets that were subject to the restriction or encumbrance at the time of the acquisition or the obligor on such Indebtedness and its Subsidiaries, (d) any
restrictions or encumbrances arising in connection with Refinancing Indebtedness; provided, however, that any restrictions and encumbrances of the type described in this clause (d) that arise under such Refinancing Indebtedness shall
not be materially more restrictive than those under the agreement creating or evidencing the Indebtedness being refunded, refinanced, replaced or extended, (e) any Permitted Lien, or any other agreement restricting the sale or other disposition of
property, securing Indebtedness permitted by this Indenture if such Permitted Lien or agreement does not expressly restrict the ability of a Subsidiary of the Company to pay dividends or make or repay loans or advances prior to default thereunder,
(f) reasonable and customary borrowing base covenants set forth in agreements evidencing Indebtedness otherwise permitted by this Indenture, (g) customary provisions restricting subletting or assignment of any lease governing a leasehold interest of
the Company or any Restricted Subsidiary, and (h) any restriction with respect to a Restricted Subsidiary imposed pursuant to an agreement entered into for the sale or disposition of all or substantially all of the Capital Stock or assets of such
Restricted Subsidiary pending the closing of such sale or disposition. 
  
 Section
3.08. Limitations on Mergers, Consolidations and Sales of Assets. 
  
 Neither the Company nor any Guarantor will consolidate or merge with or into, or sell, lease, convey or otherwise dispose of all or substantially all of its assets (including, without limitation, by way of liquidation
or dissolution), or assign any of its obligations under the Notes, the Guarantees or this Indenture (as an entirety or substantially in one transaction or in a series of related transactions), to any Person (in each case other than in a transaction
in which the Company or a Restricted Subsidiary is the survivor of a consolidation or merger, or the transferee in a sale, lease, conveyance or other disposition) unless: (i) the Person formed by or surviving such consolidation or merger (if other
than the Company or the Guarantor, as the case may be), or to which such sale, lease, conveyance or other disposition or assignment will be made (collectively, the “Successor”), is a corporation or other legal entity organized and
existing under the laws of the United States or any state thereof or the District of Columbia, and the Successor assumes by supplemental indenture in a form reasonably satisfactory to the Trustee all of the obligations of the Company or the
Guarantor, as the case may be, under the Notes or a Guarantee, as the case may be, and the Indenture, (ii) immediately after giving effect to such transaction, no Default or Event of Default has occurred and is continuing, (iii) immediately after
giving effect to such transaction and the use of any net proceeds therefrom, on a pro forma basis, the Consolidated Net Worth of the Company or the Successor (in the case of a transaction involving the Company), as the case may be,
would be at least equal to the Consolidated Net Worth of the Company immediately prior to such transaction (exclusive of any adjustments to Consolidated Net Worth attributable to transaction costs) less any amount treated as a Restricted Payment in
connection with such transaction in accordance 

  

 32 

 
with this Indenture and (iv) unless prior to such transaction the Notes are rated Investment Grade by both Rating Agencies (after which this clause (iv)
shall not apply), immediately after giving effect to such transaction, the Company could incur at least $1.00 of Indebtedness pursuant to Section 3.02(a) hereof. The foregoing provisions shall not apply to (i) a transaction involving the sale or
disposition of Capital Stock of a Guarantor, or the consolidation or merger of a Guarantor, or the sale, lease, conveyance or other disposition of all or substantially all of the assets of a Guarantor, that in any such case results in such Guarantor
being released from its Guarantee pursuant to the Indenture or (ii) a transaction the purpose of which is to change the state of incorporation of the Company or any Guarantor. 
  
 Section 3.09. Reports to Holders of Notes. 
  

The Company will file with the Commission the annual reports and the information, documents and other reports required to be filed pursuant to Section
13 or 15(d) of the Exchange Act. The Company will file with the Trustee and mail to each Holder of record of Notes such reports, information and documents within 15 days after it files them with the Commission. In the event that the Company is no
longer subject to these periodic requirements of the Exchange Act, it will nonetheless continue to file reports with the Commission and the Trustee and mail such reports to each Holder of Notes as if it were subject to such reporting requirements.
Regardless of whether the Company is required to furnish such reports to its stockholders pursuant to the Exchange Act, the Company will cause its consolidated financial statements and a “Management’s Discussion and Analysis of Results of
Operations and Financial Condition” written report, similar to those that would have been required to appear in annual or quarterly reports, to be delivered to Holders of Notes. 
  
 ARTICLE FOUR 
  
 Miscellaneous 
  
 Section 4.01. Governing Law. 
  
 The laws of the State of New York shall govern this Supplemental Indenture, the Securities of each Series and the Guarantees. 
  
 Section 4.02. No Adverse Interpretation of Other Agreements. 
  
 This Supplemental Indenture may not be used to interpret another indenture,
loan or debt agreement of the Company or a Subsidiary. Any such indenture, loan or debt agreement may not be used to interpret this Supplemental Indenture. 
  

 33 

 Section 4.03. No Recourse Against Others. 
  
 All liability described in paragraph 12 of the Notes of any director, officer, employee or stockholder, as such, of the
Company or any Guarantor is waived and released. 
  
 Section 4.04. Successors
and Assigns. 
  
 All covenants and agreements of the Company
and the Guarantors in this Supplemental Indenture and the Notes shall bind its successors and assigns. All agreements of the Trustee in this Supplemental Indenture shall bind its successors and assigns. 
  
 Section 4.05. Duplicate Originals. 
  
 The parties may sign any number of copies of this Supplemental Indenture.
Each signed copy shall be an original, but all of them together represent the same agreement. 
  
 Section 4.06. Severability. 
  
 In case any one or more of the provisions contained in this Supplemental Indenture or in the Notes shall for any reason be held to be invalid, illegal or unenforceable in any respect, such invalidity, illegality or unenforceability shall
not affect any other provisions of this Supplemental Indenture or of the Notes. 
  

 34 

 SIGNATURES 
  
 IN WITNESS WHEREOF, the parties have caused this Supplemental Indenture to be duly executed, all as of the date first above written. 
  

	D.R. HORTON, INC.
		
	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 Samuel R. Fuller
 Executive Vice President, Treasurer and
 Chief Financial Officer

  

	 GUARANTORS:
  
 C. RICHARD DOBSON BUILDERS, INC.
 CHI CONSTRUCTION COMPANY
 CHTEX OF TEXAS, INC.
 CONTINENTAL HOMES, INC.
 CONTINENTAL RESIDENTIAL, INC.
 D.R. HORTON, INC.—BIRMINGHAM
 D.R. HORTON, INC.—CHICAGO
 D.R. HORTON, INC.—DENVER
 D.R. HORTON, INC.—DIETZ-CRANE
 D.R. HORTON, INC.—GREENSBORO
 D.R. HORTON, INC.—JACKSONVILLE
 D.R. HORTON, INC.—LOUISVILLE
 D.R. HORTON, INC.—MINNESOTA
 D.R. HORTON, INC.—NEW JERSEY
 D.R. HORTON, INC.—PORTLAND
 D.R. HORTON, INC.—SACRAMENTO
 D.R. HORTON, INC.—TORREY
 D.R. HORTON LOS ANGELES HOLDING COMPANY, INC.
 D.R. HORTON MATERIALS, INC. (formerly DRH REGREM III, INC.)
 D.R. HORTON SAN DIEGO HOLDING COMPANY, INC.
 DRH CAMBRIDGE HOMES, INC.
 DRH CONSTRUCTION, INC.
 DRH
REGREM IV, INC.
 DRH REGREM V, INC.
 DRH SOUTHWEST CONSTRUCTION, INC.
 DRH TITLE COMPANY OF COLORADO, INC.
 DRH TUCSON CONSTRUCTION, INC.
 DRHI, INC.
 KDB HOMES, INC.
 MEADOWS I, LTD.
 MEADOWS VIII, LTD.
 MEADOWS IX, INC.
 MEADOWS X,
INC.
 THE CLUB AT PRADERA, INC. (formerly DRH REGREM II, INC.)

		
	 By:
	 	 /s/    SAMUEL R. FULLER

	 	 	 Samuel R. Fuller
 Treasurer

  

	 CH INVESTMENTS OF TEXAS, INC.
 MEADOWS II, LTD.

		
	 By:
	 	 /s/    Robert E. Coltin
        

	 	 	 Robert E. Coltin
 Vice President, Secretary and Treasurer

	CONTINENTAL HOMES OF TEXAS, L.P.
		
	 By:
	 	 CHTEX of Texas, Inc., its general partner

		
	 By:
	 	 /s/    SAMUEL R.
FULLER        

	 	 	Samuel R. Fuller, Treasurer
	
	 D.R. HORTON MANAGEMENT COMPANY, LTD.
 D.R. HORTON—EMERALD, LTD.
 D.R. HORTON—TEXAS,
LTD.
 DRH REGREM VII, LP

		
	 By:
	 	 Meadows I, Ltd., its general partner

		
	 By:
	 	 /s/    SAMUEL R.
FULLER        

	 	 	Samuel R. Fuller, Treasurer
	
	SGS COMMUNITIES AT GRANDE QUAY, LLC
		
	 By:
	 	 Meadows IX, Inc., a member

		
	 By:
	 	 /s/    SAMUEL R.
FULLER        

	 	 	Samuel R. Fuller, Treasurer
	 By:  
	 	 and
  
 Meadows X, Inc., a member

	 	 	 
		
	 By:
	 	 /s/    SAMUEL R.
FULLER        

	 	 	Samuel R. Fuller, Treasurer
	
	 DRH CAMBRIDGE HOMES, LLC
 DRH REGREM VIII, LLC

		
	 By:
	 	 D.R. Horton, Inc.—Chicago, a member

		
	 By:
	 	 /s/    SAMUEL R.
FULLER        

	 	 	Samuel R. Fuller, Treasurer

	 ALLEGRA, LLC
 APLAM, LLC
 WESTERN PACIFIC HOUSING CO.
 WESTERN PACIFIC HOUSING-ANTIGUA, LLC
 WESTERN PACIFIC HOUSING-AVIARA, L.P.
 WESTERN PACIFIC HOUSING-BOARDWALK, LLC
 WESTERN PACIFIC
HOUSING-BROADWAY, LLC
 WESTERN PACIFIC HOUSING-CANYON PARK, LLC
 WESTERN PACIFIC HOUSING-CARMEL, LLC
 WESTERN PACIFIC HOUSING-CARRILLO, LLC
 WESTERN PACIFIC HOUSING-COMMUNICATIONS HILL, LLC
 WESTERN PACIFIC
HOUSING-CREEKSIDE, LLC
 WESTERN PACIFIC HOUSING-CULVER CITY, L.P.
 WESTERN PACIFIC HOUSING-LOMAS VERDES, LLC
 WESTERN PACIFIC HOUSING-LOST HILLS PARK, LLC
 WESTERN PACIFIC HOUSING-MCGONIGLE CANYON, LLC
 WESTERN PACIFIC
HOUSING-MOUNTAINGATE, L.P.
 WESTERN PACIFIC HOUSING-NORCO ESTATES, LLC
 WESTERN PACIFIC HOUSING-OSO, L.P.
 WESTERN PACIFIC HOUSING-PARK AVENUE EAST, LLC
 WESTERN PACIFIC HOUSING-PARK AVENUE WEST, LLC
 WESTERN PACIFIC
HOUSING-PLAYA VISTA, LLC
 WESTERN PACIFIC HOUSING-ROBINHOOD RIDGE, LLC
 WESTERN PACIFIC HOUSING-SANTA FE, LLC
 WESTERN PACIFIC HOUSING-SCRIPPS II, LLC
 WESTERN PACIFIC HOUSING-SCRIPPS, L.P.
 WESTERN PACIFIC
HOUSING-SEACOVE, L.P.
 WESTERN PACIFIC HOUSING-STUDIO 528, LLC
 WESTERN PACIFIC HOUSING-TERRA BAY DUETS, LLC
 WESTERN PACIFIC HOUSING-TORRANCE, LLC
 WESTERN PACIFIC HOUSING-TORREY COMMERCIAL, LLC
 WESTERN PACIFIC
HOUSING-TORREY MEADOWS, LLC
 WESTERN PACIFIC HOUSING-TORREY MULTI-FAMILY, LLC
 WESTERN PACIFIC HOUSING-TORREY VILLAGE CENTER, LLC
 WESTERN PACIFIC HOUSING-VINEYARD TERRACE, LLC
 WESTERN PACIFIC HOUSING-WINDEMERE, LLC
 WESTERN PACIFIC
HOUSING-WINDFLOWER, L.P.
 WPH-CAMINO RUIZ, LLC
 WPH-HPH, LLC

		
	 By:
	 	 LAMCO Housing, Inc.,
 its Member or General Partner

	 	 	 
		
	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 Samuel R. Fuller
 Vice President

	 SCHULER HOMES OF ARIZONA LLC
 SHA CONSTRUCTION LLC

		
	 By:
	 	 SRHI LLC,
 its Member

		
	 By:
	 	 SLHR of Nevada, Inc.,
 its Member

		
	 By:
	 	 /s/    Samuel R. Fuller

Samuel R. Fuller
 Vice President

	
	 HPH HOMEBUILDERS 2000 L.P.
 PORTER GP LLC

		
	 By:
	 	 WPH-HPH, LLC,
 its General Partner or Member

		
	 By:
	 	 LAMCO Housing, Inc.,
 its Member

		
	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 Samuel R. Fuller
 Vice President

	 AP LHI, INC.
 AP WESTERN GP CORPORATION
 AP WP OPERATING CORPORATION
 LAMCO HOUSING, INC.
 MELODY HOMES, INC.
 MELMORT
CO.
 SCHULER HOMES OF CALIFORNIA, INC.
 SCHULER HOMES OF OREGON, INC.
 SCHULER HOMES OF WASHINGTON, INC.
 SCHULER MORTGAGE, INC.
 SCHULER REALTY HAWAII, INC.
 SHLR OF CALIFORNIA, INC.
 SHLR OF COLORADO, INC.
 SHLR
OF NEVADA, INC.
 SHLR OF UTAH, INC.
 SHLR OF WASHINGTON, INC.
 VERTICAL CONSTRUCTION CORPORATION
 WESTERN PACIFIC FUNDING, INC.
 WESTERN PACIFIC HOUSING MANAGEMENT, INC. 
 WESTERN PACIFIC HOUSING, INC.

		
	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 Samuel R. Fuller
 Vice President

  

	
	D.R. HORTON-SCHULER HOMES, LLC
		
	 By:
	 	 Vertical Construction Corporation,
 its
Manager

  

	 	 	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 	 	 Samuel R. Fuller
 Vice President

  

	
	SRHI LLC
		
	 By:
	 	 SHLR of Nevada, Inc.,
 its Member

  

			
	 	 	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 	 	 Samuel R. Fuller
 Vice President

  

	
	SSHI LLC
		
	 By:
	 	 SHLR of Washington, Inc.,
 its Member

  

	 	 	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 	 	 Samuel R. Fuller
 Vice President

  

	
	 WESTERN PACIFIC HOUSING-COPPER CANYON, LLC
 WESTERN PACIFIC HOUSING-PACIFIC PARK II, LLC
 WESTERN PACIFIC HOUSING-POINSETTIA, L.P.
 WESTERN PACIFIC HOUSING-DEL VALLE, LLC

		
	 By:
	 	 AP Western GP Corporation,
 its Member or General Partner

  

	 	 	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 	 	 Samuel R. Fuller
 Vice President

	WESTERN PACIFIC HOUSING-RIVER RIDGE, LLC
		
	 By:
	 	 AP LHI, Inc.,
 its Member 

			
	 	 	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 	 	 Samuel R. Fuller
 Vice President

	
	AP WP PARTNERS, L.P.
		
	 By:
	 	 AP WP Operating Corporation,
 its General Partner 

			
	 	 	 By:
	 	 /s/    Samuel R. Fuller

	 	 	 	 	 Samuel R. Fuller
 Vice President

 AMERICAN STOCK TRANSFER & TRUST 
 COMPANY, as Trustee 

		
	 By:
	 	 /s/    Herbert J. Lemmer

	 	 	 Name:  Herbert J. Lemmer
 Title:  Vice President

 Exhibit A 
  
 THIS SECURITY IS A GLOBAL SECURITY WITHIN THE MEANING OF THE INDENTURE HEREINAFTER REFERRED TO AND IS REGISTERED IN THE NAME
OF A DEPOSITORY OR A NOMINEE OF A DEPOSITORY OR A SUCCESSOR DEPOSITORY. THIS SECURITY IS NOT EXCHANGEABLE FOR SECURITIES REGISTERED IN THE NAME OF A PERSON OTHER THAN THE DEPOSITORY OR ITS NOMINEE EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE
INDENTURE, AND NO TRANSFER OF THIS SECURITY (OTHER THAN A TRANSFER OF THIS SECURITY AS A WHOLE BY THE DEPOSITORY TO A NOMINEE OF THE DEPOSITORY OR BY A NOMINEE OF THE DEPOSITORY TO THE DEPOSITORY OR ANOTHER NOMINEE OF THE DEPOSITORY) MAY BE
REGISTERED EXCEPT IN THE LIMITED CIRCUMSTANCES DESCRIBED IN THE INDENTURE. 
  
 UNLESS THIS CERTIFICATE IS PRESENTED BY AN AUTHORIZED REPRESENTATIVE OF THE DEPOSITORY TRUST COMPANY, A NEW YORK CORPORATION (“DTC”), TO THE 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. 
  

 A-1 

 D.R. HORTON, INC. 
  
 5.875% SENIOR NOTES DUE 2013 
  

	No.	 	CUSIP No.:

  
 D.R. Horton, Inc., a Delaware
corporation, promises to pay to
                                        
     
  

	 or registered assigns
	 	 	  	 
	 the principal sum of
	 	 	  	Dollars on July 1, 2013

  
 Interest Payment Dates: January 1 and
July 1 commencing January 1, 2004 
  
 Interest Record Dates: December 15 and June
15 
  

	 Dated:
  

	D.R. HORTON, INC.
		
	 By:
	 	  

	 	 	 Name:
 Title:

  

		
	 By:
	 	  

	 	 	 Name:
 Title:

  
 American Stock Transfer &
Trust Company, as Trustee, certifies that this is 
 one of the Securities referred to in the within mentioned Indenture. 
  

		
	 	 	 Date:

		
	 By:
	 	  

	 	 	Authorized Signatory

  

 A-2 

 D.R. HORTON, INC. 
  
 5.875% Senior Notes due 2013 
  

	1.	 	Interest. 

  
 D.R. HORTON, INC. (the “Company”), a Delaware corporation, promises to pay interest on the principal amount of this Security at the rate per
annum shown above. The Company will pay interest semiannually on January 1 and July 1 of each year, commencing January 1, 2004, until the principal is paid or made available for payment. Interest on the Securities will accrue from the most recent
date to which interest has been paid or duly provided for or, if no interest has been paid, from the date of original issuance, provided that, if there is no existing default in the payment of interest, and if this Security is authenticated between
a record date referred to on the face hereof and the next succeeding interest payment date, interest shall accrue from such interest payment date. Interest will be computed on the basis of a 360-day year of twelve 30-day months. 
  

	2.	 	Method of Payment. 

  
 The Company will pay interest on the Securities (except defaulted interest, if any, which will be paid on such special payment date to Holders of record
on such special record date as may be fixed by the Company) to the persons who are registered Holders of Securities at the close of business on the December 15 and June 15 immediately preceding the interest payment date. Holders must surrender
Securities to a Paying Agent to collect principal payments. The Company will pay principal and interest in money of the United States that at the time of payment is legal tender for payment of public and private debts. 
  

	3.	 	Paying Agent and Registrar. 

  
 Initially, American Stock Transfer & Trust Company (the “Trustee”) will act as Paying Agent and Registrar. The Company may change or appoint
any Paying Agent, Registrar or co-Registrar without notice. The Company or any of its Subsidiaries or any of their Affiliates may act as Paying Agent, Registrar or co-registrar. 
  

	4.	 	Indenture. 

  
 The Company issued the Securities under an Indenture dated as of June 9, 1997 among the Company, the Guarantors and the Trustee, as supplemented (the
“Indenture”). The terms of the Securities and the Guarantees include those stated in the Indenture and those made part of the Indenture by reference to the Trust Indenture Act of 1939 (“TIA”) as in effect on the date of the
Indenture. The Securities and the Guarantees are subject to all such terms, and Holders are referred to the Indenture and the Act for a statement of them. Capitalized terms not defined herein have the meanings given to those terms in the Indenture.

  
 The Company will furnish to any Holder upon written request
and without charge a copy of the Indenture and the applicable Authorizing Resolution or supplemental indenture. Requests may be made to: D.R. Horton, Inc., 1901 Ascension Blvd., Suite 100, Arlington, Texas 76006, Attention: Chief Financial Officer.

  

 A-3 

	5.	 	Optional Redemption. 

  
 (a) Except as set forth below, the Securities are not redeemable prior to July 1, 2008. Thereafter, the Securities will be redeemable in whole or in part,
from time to time at the option of the Company, at the following redemption prices (expressed as percentages of principal amount) if redeemed during the twelve month period beginning with July 1 of the year indicated below, in each case together
with accrued and unpaid interest thereon, if any, to the date of redemption: 
  

	 Year

	  	Percentage

	 
	 2008
	  	102.938	%
	 2009
	  	101.958	%
	 2010
	  	100.979	%
	 2011 and thereafter
	  	100.000	%

  
 (b) In addition, at
any time and from time to time prior to July 1, 2006, the Company may redeem Securities with the net cash proceeds of one or more Public Equity Offerings by the Company, at a redemption price equal to 105.875% of the principal amount of such
Securities, plus accrued and unpaid interest thereon, if any, to the date of redemption; provided, that at least 65% of the aggregate principal amount of Securities, excluding any Securities held by the Company or any of its Affiliates,
remains outstanding immediately after the occurrence of such redemption. Notice of any such redemption must be given within 60 days after the date of the closing of the relevant Public Equity Offering. 
  

	6.	 	Selection and Notice of Redemption 

  
 Selection of the Securities or portions thereof for redemption pursuant to the foregoing shall be made by the Trustee only on a pro rata basis or on as
nearly a pro rata basis as is practicable (subject to the procedures of The Depository Trust Company), unless such method is otherwise prohibited. Notice of redemption will be mailed at least 30 days but not more than 60 days before the redemption
date to each Holder whose Securities are to be redeemed at the registered address of such Holder. Securities in denominations larger than $1,000 may be redeemed in part. On and after the redemption date, interest ceases to accrue on the Securities
or portions thereof called for redemption, provided that if the Company shall default in the payment of such Securities at the redemption price together with accrued interest, interest shall continue to accrue at the rate borne by the Securities.

  

	7.	 	Denominations, Transfer, Exchange. 

  
 The Securities are in registered form only without coupons in denominations of $1,000 and integral multiples of $1,000. A Holder may transfer or exchange
Securities by presentation of such Securities to the Registrar or a co-Registrar with a request to register the transfer or to exchange them for an equal principal amount of Securities of other denominations. The Registrar may require a Holder,
among other things, to furnish appropriate endorsements and transfer documents and to pay any taxes and fees required by law or permitted by the Indenture. The Registrar need not transfer or exchange any Security selected for redemption, except the
unredeemed part thereof if the Security is redeemed in part, or transfer or exchange any Securities for a period of 15 days before a selection of Securities to be redeemed. 
  

 A-4 

	8.	 	Persons Deemed Owners. 

  
 The registered Holder of this Security shall be treated as the owner of it for all purposes. 
  

	9.	 	Unclaimed Money. 

  
 If money for the payment of principal or interest remains unclaimed for two years, the Trustee or Paying Agent will pay the money back to the Company at
its request. After that, Holders entitled to the money must look to the Company for payment unless an abandoned property law designates another person. 
  

	10.	 	Amendment, Supplement, Waiver. 

  
 Subject to certain exceptions, the Indenture or the Securities may be amended or supplemented with the consent of the Holders of at least a majority in
principal amount of the outstanding Securities and any past default or compliance with any provision relating to the Securities may be waived in a particular instance with the consent of the Holders of a majority in principal amount of the
outstanding Securities. Without the consent of any Holder, the Company and the Trustee may amend or supplement the Indenture or the Securities to cure any ambiguity, defect or inconsistency, to provide for uncertificated Securities in addition to or
in place of certificated Securities, to create a Series and establish its terms, to remove a Guarantor which, in accordance with the terms of the Indenture, ceases to be liable in respect of its Guarantee, or to make any other change, provided such
action does not adversely affect the rights of any Holder. 
  

	11.	 	Successor Corporation. 

  
 When a successor corporation assumes all the obligations of its predecessor under the Securities and the Indenture, the predecessor corporation will be
released from those obligations. 
  

	12.	 	Trustee Dealings With Company. 

  
 American Stock Transfer & Trust Company, the Trustee under the Indenture, in its individual or any other capacity, may make loans to, accept deposits
from, and perform services for the Company or its affiliates, and may otherwise deal with the Company or its affiliates, as if it were not Trustee. 
  

	13.	 	No Recourse Against Others. 

  
 A 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 the Indenture or for any claim based on, in respect of or by reason of, such obligations or their creation. Each Holder by accepting a Security waives and releases all such liability. The waiver and release are part of the consideration for the
issue of the Securities. 
  

	14.	 	Discharge of Indenture. 

  
 The Indenture contains certain provisions pertaining to defeasance, which provisions shall for all purposes have the same effect as if set forth herein.

  

 A-5 

	15.	 	Authentication. 

  
 This Security shall not be valid until the Trustee signs the certificate of authentication on the other side of this Security. 
  

	16.	 	Abbreviations. 

  
 Customary abbreviations may be used in the name of a Holder or an assignee, such as: TEN COM (= tenants in common), TEN ENT (= tenants by the entireties),
JT TEN (= joint tenants with right of survivorship and not as tenants in common), CUST (= custodian), and U/G/M/A (= Uniform Gift to Minors Act). 
  

 A-6 

 ASSIGNMENT FORM 
  

	
	 If you the Holder want to assign this Security, fill in the form below:

	
	 I or we assign and transfer this Security to

	
	

	
	

	(Insert assignee’s social security or tax ID number)

  
  

	
	

	
	

	
	

	(Print or type assignee’s name, address, and zip code)

  
 and irrevocably appoint 
  

	
	

	agent to transfer this Security on the books of the Company. The agent may substitute another to act for him.
	
	

  

		
	 Date:                            
	 	 Your
signature:                                      
                                  

		
	 	 	 (Sign exactly as your name appears on the other side of this Security)

		
	 	 	 
	
	 Signature Guarantee:    
                                       
                                        
                                        
                                        
             

		
	 	 	Signature must be guaranteed by participant in a recognized Signature Guarantee Medallion Program (or other signature guarantor program reasonably acceptable to the
Trustee)

  

 A-7 

 [FORM OF NOTATION ON SECURITY RELATING TO GUARANTEE] 
  
 GUARANTEE 
  
 The undersigned (the “Guarantors”) have unconditionally guaranteed, jointly and severally (such guarantee by each
Guarantor being referred to herein as the “Guarantee”) (i) the due and punctual payment of the principal of and interest on the Securities, whether at maturity, by acceleration or otherwise, the due and punctual payment of interest on the
overdue principal and interest, if any, on the Securities, to the extent lawful, and the due and punctual performance of all other obligations of the Company to the Holders or the Trustee all in accordance with the terms set forth in Article Nine of
the Indenture and (ii) in case of any extension of time of payment or renewal of any Securities or any of such other obligations, that the same will be promptly paid in full when due or performed in accordance with the terms of the extension or
renewal, whether at stated maturity, by acceleration or otherwise. 
  
 No past, present or future stockholder, officer, director, employee or incorporator, as such, of any of the Guarantors shall have any liability under the Guarantee by reason of such person’s status as stockholder, officer, director,
employee or incorporator. Each holder of a Security by accepting a Security waives and releases all such liability. This waiver and release are part of the consideration for the issuance of the Guarantees. 
  
 Each holder of a Security by accepting a Security agrees that any Guarantor
named below shall have no further liability with respect to its Guarantee if such Guarantor otherwise ceases to be liable in respect of its Guarantee in accordance with the terms of the Indenture. 
  

 A-8 

 The Guarantee shall not be valid or obligatory for any purpose until the certificate of authentication on
the Securities upon which the Guarantee is noted shall have been executed by the Trustee under the Indenture by the manual signature of one of its authorized officers. 
  

	 [Guarantors]

		
	 By:
	 	  

	 	 	 Title:

  

 A-9<PAGE>

                                                                    EXHIBIT 10.1

*Certain confidential information contained in this document, marked by
brackets, has been omitted and filed with the Securities and Exchange Commission
pursuant to Rule 24b-2 of the Securities Exchange Act of 1934, as amended.

                             BEXXAR SUPPLY AGREEMENT

                                     between

              MDS (Canada) Inc., through its division, MDS Nordion,

                                       and

                          Coulter Pharmaceutical, Inc.

                             and Corixa Corporation

                            Dated as of July 1, 2003

<PAGE>

                             BEXXAR SUPPLY AGREEMENT

         THIS SUPPLY AGREEMENT (this "Agreement") is made, effective as of the
1st day of July, 2003 (the "Effective Date"), between MDS (Canada) Inc., through
its division, MDS Nordion ("Nordion"), and Coulter Pharmaceutical, Inc.
("Coulter") and Corixa Corporation (together with Coulter, collectively
"Corixa"), each a "Party" and collectively, the "Parties."

                                    RECITALS

         WHEREAS, Nordion and Coulter, a subsidiary of Corixa, entered into that
certain Development Agreement, dated November 15, 1995 (the "Development
Agreement"), that certain Facilities Agreement, dated August 31, 1998 (the
"Facilities Agreement"), and that certain Supply Agreement, dated August 31,
1998 (the "Previous Supply Agreement") (collectively, the Development Agreement,
the Facilities Agreement and the Previous Supply Agreement shall be referred to
herein as the "Previous Agreements"); and

         WHEREAS, the Parties wish to terminate the Previous Agreements and
continue the relationship contemplated by the Facilities Agreement and the
Previous Supply Agreement in accordance with the terms contained herein;

         NOW, THEREFORE, in consideration of the foregoing and the mutual
promises contained in this Agreement, the Parties agree as follows:

1.       Definitions.

         As used in this Agreement, the following terms shall have the meanings
set forth below:

         1.1      "Affiliate" shall mean any entity or person which controls, is
controlled by or is under common control with either Party. For purposes of this
Section 1.1, control shall mean (a) in the case of corporate entities, the
direct or indirect ownership of more than one-half of the stock or participating
shares entitled to vote for the election of directors, and (b) in the case of a
partnership, the power to direct the management and policies of such
partnership.

         1.2      "Adverse Events" shall mean any undesirable event or reaction
reported to or known by the Parties regarding the Labeled Drug that is
determined to be potentially associated with the use of the Labeled Drug in
humans.

         1.3      "[*]" shall have the meaning given to it in Section 4.7(a).

         1.4      "Authorization to Manufacture" shall have the meaning given to
it in Section 3.1(e).

         1.5      "Agreement" shall have the meaning given to it in the first
paragraph hereof.

         1.6      "B1 Antibody" shall mean the IgG2a anti-CD-20 murine
monoclonal antibody meeting the specifications in Exhibit 1.6 supplied by Corixa
to Nordion for the purposes of this Agreement.

----------------------------------
* Confidential treatment requested.

<PAGE>

         1.7      "Background Technology" shall mean all Nordion proprietary
technology, including patents, know-how, techniques, methods, processes and
trade secrets, which are licensed to Nordion by a party other than Corixa, or
owned, or controlled by Nordion and which Nordion owned or controlled or
received a license to prior to July 10, 1995 as evidenced by a writing or
prototype or as otherwise can be demonstrated by Nordion to have been owned or
controlled or licensed by it prior to July 10, 1995.

         1.8      "Batch" shall mean a production batch of Labeled Drug
manufactured under this Agreement.

         1.9      "Batch Capacity" shall mean the capacity of the Facility to
produce Labeled Drug.

         1.10     "Bexxar Equipment" shall mean the Corixa Equipment and the
Nordion Equipment.

         1.11     "Bexxar Freezer Carrier" shall mean the freezer trailer
located at the Nordion Site used for storage (or transport) of the Labeled Drug,
which trailer is owned by Corixa, and at Corixa's request is operated by Nordion
or its agents.

         1.12     "BLA" shall mean a Biologics License Application, as defined
by the regulations promulgated under the FD&C Act and the United States Public
Health Services Act, and any supplements thereunder, as amended from time to
time, with respect to Labeled Drug.

         1.13     "Breach Notice" shall have the meaning given to it in Section
11.4.

         1.14     "Carrier" shall mean a carrier approved in advance by Corixa.

         1.15     "Carrier Hub Delivery" shall have the meaning given to it in
Section 3.2(c)(ii).

         1.16     "CD-20 Antigen Cells" shall mean the CD20-positive indicator
cell line used for the determination of final drug product potency in the
Immunoreactive Fraction Assay, meeting the specifications in Exhibit 1.16,
supplied by Corixa to Nordion for the purposes of this Agreement.

         1.17     "cGMP" shall mean the current good manufacturing practices
required by the FDA and set forth in the FD&C Act or FDA regulations, policies,
or guidelines in effect at a particular time for the manufacture, testing and
quality control of pharmaceutical materials as applied to biologics, together
with any other applicable regulations, except to the extent that the standards
for the manufacture, testing and quality control of pharmaceutical materials as
applied to biologics, or other applicable regulations, are higher or more
stringent in any other country, state or locality in the Territory than those
required by the FDA, in which case such country, state or locality's standards
will apply.

         1.18     "Change Control Operating Procedure" shall have the meaning
given to it in Section 4.5.

         1.19     "Claim" shall have the meaning given to it in Section 13.4.

                                       -2-

<PAGE>

         1.20     "Clinical Trial(s)" shall mean any trial for clinical
development of pharmaceutical products defined as "Phase I," "Phase II," "Phase
III," or "Treatment IND" in FDA regulations, as amended from time to time.

         1.21     "CMC" shall have the meaning given to it in Section 5.11(b).

         1.22     "Commercial Forecast" shall have the meaning given to it in
Section 3.1(c).

         1.23     "Commercial Forecast Period" shall have the meaning given to
it in Section 3.1(c).

         1.24     "Commercial Supply" shall mean the supply of Labeled Drug by
Nordion to Corixa for sale after regulatory approval of Labeled Drug has been
received by Corixa from the FDA in the United States.

         1.25     "Complaint" shall mean any commentary, verbal or written,
received regarding dissatisfaction with the performance of the Labeled Drug in
relation to an Adverse Event, quality, transportation, quantity received versus
quantity ordered, scheduling, packaging or other situations not captured by the
foregoing headings.

         1.26     "Confidential Information" shall have the meaning given to it
in Section 14.1.

         1.27     "Corixa" shall have the meaning given to it in the first
paragraph of this Agreement.

         1.28     "Corixa Equipment" shall mean that equipment and other items
listed on Exhibit 1.28.

         1.29     "Corixa IP" shall mean any and all patents, trade secrets,
know-how, copyrights, trademarks and other intellectual property rights,
wherever existing, owned, controlled or licensed by Corixa.

         1.30     "Coulter" shall have the meaning given to it in the first
paragraph of this Agreement.

         1.31     "CPI" shall mean the Canadian Consumer Price Index.

         1.32     "Delay" shall have the meaning given it in Section 6.1(a).

         1.33     "Delay Cost" shall have the meaning given it in Section
6.1(c).

         1.34     "Development Agreement" shall have the meaning given to it in
the Recitals.

         1.35     "Deviations" shall mean unplanned events or departures from
approved procedures used in the manufacture or testing of Labeled Drug.

         1.36     "Dispute" shall have the meaning given to it in Section
15.3(a).

         1.37     "DMF" shall have the meaning given to it in Section 5.11(b).

         1.38     "Effective Date" shall have the meaning given to it in the
first paragraph of this Agreement.

                                       -3-

<PAGE>

         1.39     "Environmental Regulations" shall mean any federal, state,
provincial, territorial or local environmental, health and safety and radiation
safety laws or regulations which are applicable to the manufacture of Labeled
Drug, or the removal of Bexxar Equipment and supplies and space used by or for
Nordion in the development, manufacture, storage, packaging, testing or delivery
of Labeled Drug, safely from service and render such equipment, supplies and
space safe, or dispose of it, as required by applicable laws and regulations.

         1.40     "Extended Term" shall have the meaning given to it in Section
11.2.

         1.41     "Facility" shall mean the rooms and areas at the Nordion Site
where Labeled Drug is actually manufactured, processed, handled, inspected,
stored or delivered (including, without limitation, the Bexxar Freezer Carrier
when Labeled Drug is stored in such carrier and delivered therefrom).

         1.42     "Facilities Agreement" shall have the meaning given to it in
the Recitals.

         1.43     "FDA" shall mean the United States Food and Drug
Administration or any successor agency thereto.

         1.44     "FD&C Act" shall mean the United States Federal Food, Drug and
Cosmetic Act, as amended.

         1.45     "Final Destination" shall have the meaning given to it in
Section 3.2(c)(i).

         1.46     "Final Destination Delivery Time" shall have the meaning given
to it in Section 3.2(c)(i).

         1.47     "Firm Order" shall have the meaning given to it in Section
3.1(d).

         1.48     "Forecast" shall have the meaning given to it in Section
3.1(b).

         1.49     "Forecast Period" shall have the meaning given to it in
Section 3.1(b).

         1.50     "Force Majeure" shall have the meaning given to it in Section
16.9.

         1.51     "General Claims Against Corixa" shall have the meaning given
to it in Section 13.2(a).

         1.52     "General Claims Against Nordion" shall have the meaning given
to it in Section 13.1(a).

         1.53     "Hot Cells" shall mean the lead and stainless steel enclosed
structure which provides for the containment of radioactive materials identified
as cells 26, 28 and 29 at the Facility.

         1.54     "IND" shall mean an Investigational New Drug application and
any supplements thereto, as defined in FDA regulations, as amended from time to
time.

         1.55     "Indemnitee" shall have the meaning given to it in Section
13.4.

         1.56     "Indemnitor" shall have the meaning given to it in Section
13.4.

                                       -4-

<PAGE>

         1.57     "Initial Term" shall have the meaning given to it in Section
11.1.

         1.58     "Iodine Supply Agreement" shall have the meaning given to it
in Section 2.3.

         1.59     "IP Claims Against Corixa" shall have the meaning given to it
in Section 13.3(a).

         1.60     "IP Claims Against Nordion" shall have the meaning given to it
in Section 13.3(b).

         1.61     "Isotope" shall mean iodine (131)I.

         1.62     "Isotope Specification" shall mean those specifications set
out in Exhibit 1.61(a) for [*] Isotope or set out in Exhibit 1.61(b) for [*]
Isotope, as appropriate.

         1.63     "Labeled Drug" shall mean a pharmaceutical product containing
the Isotope-labeled B1 Antibody in either dosimetric or therapeutic final dosage
form meeting Specifications, for use in Clinical Trials or for commercial sale,
which has been, or is being, manufactured in accordance with the Process,
compounded, formulated, finished, filled, labeled, packaged and/or delivered by
Nordion pursuant to this Agreement.

         1.64     "Maximum Batch Size" shall mean a [*] Ci (Curie) Batch for
therapeutic Labeled Drug and a [*] Ci (Curie) Batch for dosimetric Labeled Drug.

         1.65     "Nonconformity" shall mean a failure of the Labeled Drug to
meet Specifications.

         1.66     "Nordion" shall have the meaning given to it in the first
paragraph of this Agreement.

         1.67     "Nordion Equipment" shall mean the equipment owned or
controlled by Nordion, excluding Corixa Equipment identified in Exhibit 1.28,
used in the manufacture, packaging or testing of Labeled Drug.

         1.68     "Nordion IP" shall mean any and all patents, trade secrets,
know-how, copyrights, trademarks and other intellectual property rights,
wherever existing, owned, controlled or licensed by Nordion.

         1.69     "Nordion Quality Policies" shall have the meaning given to it
in Section 5.1.

         1.70     "Nordion Site" shall mean Nordion's plant (including, without
limitation, the Facility) located in Ottawa, Ontario, Canada.

         1.71     "Nordion Site Delivery" shall have the meaning given to it in
Section 3.2(c)(i).

         1.72     "Party" or "Parties" shall have the meaning given to it in
this first paragraph of this Agreement.

         1.73     [*] shall mean [*] described at Exhibit 5.12(c).

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         1.74     "Post-Commercialization Firm Order" shall have the meaning
given to it in Section 3.1(c).

         1.75     "Pre-Commercialization Firm Order" shall have the meaning
given to it in Section 3.1(b).

         1.76     "Previous Agreements" shall have the meaning given to it in
the Recitals.

         1.77     "Previous Supply Agreement" shall have the meaning given to it
in the Recitals.

         1.78     "Process" shall mean the process of formulation and dispensing
described in Nordion's Standard Operating Procedure 960702.SOP and 960703.SOP.

         1.79     "Proposed Response" shall have the meaning given to it in
Section 5.12(a)(ii).

         1.80     "Quality Policy Manual" shall mean that manual which provides
(i) how the Corixa Quality Assurance and Nordion Quality Assurance/Quality
Control departments interact with each other and (ii) the quality assurance
responsibilities of each in relation to the manufacturing, labeling, Release and
delivery of Labeled Drug.

         1.81     "Recall" shall have the meaning given to it in Section 6.1(b).

         1.82     "Release" shall mean the written quality assurance
authorization to deliver Labeled Drug, which is initially approved by Nordion
and finally approved by Corixa, pursuant to Section 5.2 and applicable
protocols.

         1.83     "Scheduled Batch Completion Date" shall mean [*] with respect
to a therapeutic Batch and [*] with respect to a dosimetric Batch and such other
scheduled production day as agreed pursuant to a Forecast, Commercial Forecast
or Firm Order.

         1.84     "Scheduled Vials" means, with respect to a Batch that is the
subject of a Delay, the total number of vials of Labeled Drug (i) ordered by
Corixa pursuant to an Authorization to Manufacture, and any changes thereto made
in accordance with Section 3.1(f), and (ii) finalized for delivery pursuant to
Section 3.2 (a). For the avoidance of doubt, with respect to the dosimetric form
of Labeled Drug, Scheduled Vials shall not include any vials of the dosimetric
form scheduled to be allocated into inventory and not scheduled for delivery
until at least the week following the scheduled date of Release of such Delayed
Batch.

         1.85     "SOW" shall have the meaning given to it in Section 4.7(a).

         1.86     "Specifications" shall mean the Labeled Drug specifications as
set forth in Exhibit 1.86.

         1.87     "Territory" shall mean the United States of America and Canada
and any other countries mutually agreed to by the Parties.

         1.88     "Territory DMF" shall have the meaning given to it in Section
5.11(b).

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         1.89     "Validation" or "Validate" or "Validated" shall mean the
program mutually agreed to by the Parties by which documented evidence provides
a high degree of assurance that the Process, Bexxar Equipment and Facility meet
applicable regulatory requirements for validation and will consistently produce
Labeled Drug that meets Specifications and quality attributes as mutually agreed
by the Parties and the Process is effective and reproducible.

2.       Supply.

         2.1      Labeled Drug.

                  (a)      General Terms. Nordion shall use the Process to
radiolabel B1 Antibody with Isotope to produce Labeled Drug that meets the
Specifications and is manufactured in conformity with cGMP requirements and all
other applicable laws, rules and regulations of the Territory and shall deliver
Labeled Drug for shipment as directed by Corixa. During the term of this
Agreement and any renewals thereof, Nordion shall manufacture and provide Corixa
with Labeled Drug that may be ordered by Corixa under this Agreement for the
purposes of Clinical Trial and commercial sale of Labeled Drug in the Territory.

                  (b)      Batch Capacity and Maximum Batch Size. Nordion shall
maintain the Batch Capacity necessary to produce [*] Batches per [*] period, up
to a maximum of [*] Batches per year. Nordion hereby agrees to produce such
Batches of Labeled Drug up to a Maximum Batch Size at the Facility to the extent
ordered by Corixa. It is understood and agreed that Corixa may order a Batch
that is smaller than the Maximum Batch Size in accordance with the Process. In
the event Corixa's requirements for Batch Capacity or Maximum Batch Size
increase, the Parties shall meet in good faith to discuss increasing the Batch
Capacity or the Maximum Batch Size.

         2.2      B1 Antibody.

                  (a)      General Terms. Corixa or, at Corixa's discretion, its
designee shall provide B1 Antibody and CD-20 Antigen Cells to Nordion, [*], in
sufficient quantities and quality to allow Nordion to meet its obligations
hereunder. Nordion shall store, [*], B1 Antibody and CD-20 Antigen Cells in
accordance with the specifications designated by Corixa. Corixa shall at all
times own, including while remaining a raw material or used in the manufacture
of Labeled Drug at the Nordion Site, (i) the B1 Antibody, and (ii) the CD-20
Antigen Cells. Nordion agrees that it will use the CD-20 Antigen Cells and the
B1 Antibody provided by Corixa only for production of Labeled Drug, unless
otherwise instructed in writing by Corixa.

                  (b)      Unavailability or Scarcity of B1 Antibody. It is
understood that Corixa's obligation to supply B1 Antibody and CD-20 Antigen
Cells to Nordion is conditional upon its ability to obtain a sufficient supply
of the B1 Antibody and CD-20 Antigen Cells. Corixa will use commercially
reasonable efforts to notify Nordion upon Corixa's knowledge of a shortage of
the B1 Antibody or CD-20 Antigen Cells if such shortage will impact the
manufacture of Labeled Drug. Corixa shall not be liable for any delays in the
supply of B1 Antibody or CD-20 Antigen Cells under Section 2.2(a); provided,
however, that any such delays in the supply of B1 Antibody or CD-20 Antigen
Cells will excuse Nordion's performance of actions related to such B1 Antibody
or CD-20 Antigen Cells to the extent Nordion's non-performance was caused by
such delay in the supply of B1 Antibody or CD-20

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Antigen Cells and that such delay or failure to supply B1 Antibody or CD-20
Antigen Cells (unless due to a Force Majeure) will not impact Corixa's minimum
purchase commitment.

         2.3      Isotope. The supply of [*] Isotope shall be governed by the
Iodine Supply Agreement dated September 13, 2000 between Nordion and Coulter
(the "Iodine Supply Agreement"). Upon termination or expiration of the Iodine
Supply Agreement, Corixa shall be entitled to purchase [*] Isotope from Nordion
in accordance with the pricing set out in Exhibit 9.1, or at Corixa's option,
and upon Isotope specifications and conditions to be agreed with Nordion, shall
be permitted to purchase [*] Isotope from a third party for use by Nordion in
the manufacture of Labeled Drug. [*] Isotope supplied by Nordion for use in
Labeled Drug shall conform to the [*] Isotope Specifications set out in Exhibit
1.61(b).

3.       Orders and Delivery.

         3.1      Forecasts.

                  (a)      [*] Forecasting. No later than [*] prior to the
commencement of each [*] during the term of this Agreement, Corixa shall
identify the number of Batches of Labeled Drug per week that Corixa estimates it
may need for the next [*]. Such estimate is non-binding and for planning
purposes only in order to allow Nordion to ensure it has all the materials
necessary to manufacture Labeled Drug, including, without limitation, enough
available Isotope.

                  (b)      Pre-Commercialization Firm Order. During the period
up to the [*] of commencement of Commercial Supply, Corixa on the [*], shall
provide Nordion with a written forecast of Corixa's Clinical Trial and/or
Commercial Supply requirements (the "Forecast") for Labeled Drug for the next[*]
(the "Forecast Period"). Nordion, at its cost, shall maintain in inventory
sufficient ingredients to manufacture the identified number of Batches provided
for in the most recent Forecast. The Forecast shall include an estimated size of
each Batch and the type of label to be used and shall set out Scheduled Batch
Completion Dates. The first [*] of Scheduled Batch Completion Dates provided by
Corixa in each Forecast shall be binding (the "Pre-Commercialization Firm
Order").

                  (c)      Post-Commercialization Firm Order. During the period
commencing after the [*] of Commercial Supply, Corixa on the [*], shall provide
Nordion with a written forecast of Corixa's Clinical Trial and/or Commercial
Supply requirements (the "Commercial Forecast") for Labeled Drug for the next
[*] (the "Commercial Forecast Period"). Nordion, at its cost, shall maintain in
inventory sufficient ingredients to manufacture the identified number of Batches
provided for in the most recent Commercial Forecast. The Forecast shall include
an estimated size of each Batch and the type of label to be used and shall set
out Scheduled Batch Completion Dates. The first [*] of Scheduled Batch
Completion Dates in each Commercial Forecast shall be binding (the
"Post-Commercialization Firm Order").

                  (d)      Firm Order. Each Pre-Commercialization Firm Order and
Post-Commercialization Firm Order shall be known as a "Firm Order". For the
avoidance of doubt, the term "binding" as used in Sections 3.1(b) and (c) refers
to the requirement for Labeled Drug to be produced on the Scheduled Batch
Completion Dates, but not to Batch size. By way of example, Exhibit 3.1 provides
a schematic outlining the procedure provided for in Section 3.1 (b) and (c)
above.

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                  (e)      Authorization to Manufacture. At least [*]
immediately prior to the Scheduled Batch Completion Date, Corixa will provide an
authorization to manufacture setting forth the Batch size and type(s) of label
(the "Authorization to Manufacture").

                  (f)      Changes. At any time until [*] Eastern Time on the
day that is at least [*] prior to the Scheduled Batch Completion Date, Corixa
may make changes to the [*] as set out in the Authorization to Manufacture.
Under extraordinary circumstances, Nordion will manufacture on days other than
normally scheduled production runs. The Parties will agree on a holiday schedule
and modify the production schedule accordingly.

                  (g)      Minimum Purchase Requirements. During the period
prior to Commercial Supply of Labeled Drug, Corixa shall [*] During the [*]
period of Commercial Supply of Labeled Drug, Corixa shall purchase at least [*]
Batches. Following the [*] period of Commercial Supply of Labeled Drug and
during each succeeding [*] period during the term of this Agreement, Corixa
shall purchase at least [*] Batches. It is expressly understood and agreed that
except for the commitments contained in this Section 3.1(g), Corixa has no
specific or minimum commitment to purchase any amounts of Labeled Drug. The
Parties further understand and agree that the minimum commitment for a given [*]
period will be reduced by a pro rata amount (rounded to the nearest whole Batch)
in the event that the Batch Capacity is reduced during such [*] period for
reasons due to Force Majeure or attributable to Nordion. By way of example only,
if the Facility were only open for [*] in a [*] period (rather than [*] then the
minimum commitment for such [*] period would be reduced by [*] percent [*] or
[*] Batches if such Batch Capacity reduction occurs during the first [*] of
Commercial Supply and [*] Batches if such Batch capacity reduction occurs
thereafter.

                  (h)      Cancellation Fees. A Batch which is the subject of a
Firm Order shall be subject to the cancellation fee specified in Section 9.2.

         3.2      Shipment and Delivery.

                  (a)      Finalizing Orders. By [*]. Eastern Time, no later
than [*] prior to the Scheduled Batch Completion Date, or at such time as
otherwise mutually agreed in writing by the Parties, Corixa will finalize [*]
and [*]. Nordion shall not ship any Batch of Labeled Drug that fails to meet
Specifications, subject to Corixa's rights under this Agreement. Nordion
reserves the right to refuse to make available for delivery Labeled Drug to a
shipping address that has not been previously licensed.

                  (b)      Designation of Final Destinations. Corixa will
provide Nordion with a list of destinations to which Nordion may be requested by
Corixa to ship Labeled Drug, no later than [*] prior to the first shipment of
Labeled Drug to any such site(s), or at such time as otherwise mutually agreed
in writing by the Parties. Nordion will promptly review each site(s) license
with respect to its ability to receive Isotope and shall advise Corixa of any
regulatory requirements for documentation establishing the legal authority of
such site(s) to receive and possess Isotope. Corixa shall promptly provide
Nordion with such documentation as Nordion may reasonably require confirming
compliance with regulatory requirements.

                  (c)      Delivery. Nordion shall make delivery of the Labeled
Drug, as follows:

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                           (i)      Except as otherwise provided below, Labeled
Drug supplied under this Agreement shall be delivered FCA (Incoterms 2000)
Carrier's vehicle at the Nordion Site by the cut off date and time the Carrier
specifies to Nordion that the Labeled Drug must be made available to such
Carrier for pick up at the Nordion Site for Carrier to be able to deliver such
Labeled Drug to the Final Destination by the Final Destination Delivery Time
("Nordion Site Delivery"). For purposes of this Section 3.2(c), the "Final
Destination" shall mean the destination specified by Corixa for delivery of the
Labeled Drug and "Final Destination Delivery Time" shall mean [*] on the date
designated by Corixa for delivery of Labeled Drug to the Final Destination, such
date to be at least [*] following the Scheduled Batch Completion Date. For the
destinations of Hawaii, Alaska and Puerto Rico, the date and [*] shall be
replaced with the date and time designated by the Carrier for delivery of
Labeled Drug to such Final Destination to meet Corixa's requirements.

                           (ii)     In the event that Nordion cannot make the
Nordion Site Delivery, such Labeled Drug may be delivered by Nordion FCA
Carrier's distribution center or hub by the cut off date and time the Carrier
specifies to Nordion the Labeled Drug must be made available to the Carrier at
the Carrier's distribution center or hub for Carrier to deliver such Labeled
Drug to the Final Destination by the Final Destination Delivery Time ("Carrier
Hub Delivery").

                           (iii)    In the event that Nordion cannot make the
Nordion Site Delivery or Carrier Hub Delivery as provided above, Nordion may
have such Labeled Drug delivered FCA the Final Destination.

4.       Manufacture.

         4.1      Failure To Meet Material Obligations. In the event that
Nordion fails to meet one or more of the material obligations under this
Agreement (except to the extent caused by Corixa or its agents during the term
hereof) or Corixa determines that Nordion will not be able to meet one or more
of the material obligations, Nordion and Corixa shall immediately meet to
discuss the matter in good faith. At such meeting, Nordion shall provide Corixa
with its best estimate as to when it will be able to meet such obligations.
Unless Nordion is able to provide Corixa with reasonable assurances, within [*]
of such meeting, that such material obligations will be met, [*] following the
notice and remedial period (if such obligations remain unremedied) contained in
Section 11.4. Nothing in this Section 4.1 shall be read to limit any of Corixa's
rights under Section 6 or otherwise. [*].

         4.2      Compliance with Law; Handling of Labeled Drug. While the B1
Antibody, Isotope and Labeled Drug are in its possession or under its control,
Nordion shall be responsible for complying with all applicable statutory and
regulatory requirements of the Territory regarding the manufacture, handling,
storage, labeling, packaging and transportation of Labeled Drug. In performing
its obligations under this Agreement, Nordion shall comply with all applicable
environmental and health and safety laws.

         4.3      Site of Manufacture. Nordion shall manufacture and package
Labeled Drug in the Facility and shall do so in compliance with all applicable
Environmental Regulations.

         4.4      Approval of Manufacturing Changes.

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                  (a)      General. Either Party may request a Specifications
change intended to maintain high standards. The Parties shall discuss in good
faith the implementation of any such requested changes; provided, however, that
Nordion shall not make any revisions to any aspect of the manufacturing or
Labeled Drug handling process without the prior written consent of Corixa in
accordance with the Change Control Operating Procedure. Corixa retains the right
and responsibility for final approval of the Specifications and labels for the
Labeled Drug. Either Party may request a Specifications change required for
compliance with a regulatory act or legal requirement imposed by an applicable
governmental entity with jurisdiction in the Territory.

                  (b)      Capital Expenditures.

                           (i)      In the event a material cGMP, legal or
regulatory change (required by regulation) to the Facility and/or pharmaceutical
areas(s) used in association with the Facility requires a capital expenditure of
an amount up to [*] US dollars [*] per regulatory event, [*] responsible for
such capital expenditure.

                           (ii)     In the event a material cGMP or legal or
regulatory change (required by regulation) to the Facility and/or pharmaceutical
areas(s) used in association with the Facility requires a capital expenditure in
excess of [*] US dollars ([*] per regulatory event, the Parties shall agree upon
the changes to be made and the amount of any necessary capital expenditure. If
the Parties disagree on the changes required to comply or costs related to a
cGMP or regulatory change, then the Parties shall agree on an independent third
party to determine the issue and the most cost effective way to achieve the
desired result. The amount of such cost in excess of [*] U.S. dollars ([*] will
be [*]. Notwithstanding the foregoing, in no event shall either Party be
required to make any such required capital expenditures in excess of [*] US
dollars [*] if Corixa determines, in its reasonable discretion, that such
required capital expenditure is not economically feasible or would otherwise
render this Agreement no longer economically viable. For the avoidance of doubt,
in the event that Nordion is unable to manufacture Labeled Drug in conformance
with cGMP requirements or applicable laws, rules or regulations, due to Corixa's
decision, pursuant to this section, not to make the required capital
expenditures to bring the Facility into conformance with cGMP requirements or
applicable laws, rules or regulations, this Agreement shall forthwith terminate.
Such termination shall not constitute a termination under Section 6, 11.3 or
11.4 and Corixa shall not be obligated to pay any termination fee in connection
with such termination.

                  (c)      Labeling and Packaging Changes. From time to time
Corixa may require labeling or packaging changes that will affect all or
substantially all of the Labeled Drug. These changes may either be initiated by
Corixa or may be a requirement resulting from changes in cGMPs. Unless such
change is required to meet cGMP requirements as provided in Section 4.4(b)
above, Corixa will reimburse Nordion for its costs associated with such a change
at a rate that is mutually agreed upon by the Parties

         4.5      Change Control Operating Procedure. The procedure to be
followed if either Corixa or Nordion desires to change any aspect of the
manufacturing procedure for Labeled Drug, including without limitation, any
change in Validation requirements, the Specifications as described in Section
4.4(a) above, the B1 Antibody specifications or the CD-20 Antigen Cell
specifications is set forth in

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the Quality Policy Manual (such procedure is hereinafter referred to as the
"Change Control Operating Procedure"). Until such time as the Change Control
Operating Procedure is agreed to by the Parties, they shall continue to follow
the existing change control procedures. In addition, Nordion undertakes not to
implement any change to the Isotope Specifications or modification to the
Isotope process that could impact the quality or safety of the Isotope or the
Labeled Drug or impact the BLA without the prior written consent of Corixa, not
to be unreasonably withheld. The Parties agree to comply with the terms of the
Quality Policy Manual, including, without limitation, such Change Control
Operating Procedure.

         4.6      Scheduled Maintenance. Subject to the remainder of this
Section 4.6, Nordion shall be entitled, at its own expense, [*] notice, to shut
down the Facility for scheduled maintenance for a maximum period not to [*]
period during any calendar year, unless otherwise mutually agreed. The shut down
shall occur during the [*], unless otherwise mutually agreed. The scheduling of
the shut down shall not interfere with Nordion's ability to deliver Labeled Drug
pursuant to a Firm Order issued by Corixa prior to Corixa's receipt of a notice
of the exact shut down dates. Corixa shall be entitled to approve the date of
such scheduled maintenance or to request that such date be rescheduled. Corixa's
approval of such scheduled maintenance shall not be unreasonably withheld.

         4.7      [*].

                  (a)      [*]. Corixa shall have the right to [*] Nordion
agrees to use commercially reasonable efforts to assist Corixa in that regard,
at Corixa's expense, upon commercially reasonable terms as agreed to in a
Statement of Work (an "SOW").

                  (b)      Process Development Work. Corixa shall have the right
to [*].

         4.8      Continuous Improvement. Any continuous improvement made by
Nordion under an SOW in the manufacture of Labeled Drug which [*] between the
Parties as agreed to in the applicable SOW.

5.       Quality Assurance and Regulatory Matters.

         5.1      Quality Assurance; Quality Control. Nordion shall implement
and perform operating procedures and controls for sampling, stability and other
testing of materials, and for Validation, documentation and Release of the
Labeled Drug and such other quality assurance and quality control procedures as
are consistent with the cGMPs and the Nordion quality policies and
documentations (collectively, "Nordion Quality Policies").

         5.2      Product Release. In connection with each Release, Nordion
shall certify in writing that each Batch of Labeled Drug was produced and tested
in compliance with (i) the Specifications, (ii) cGMP requirements, (iii) the IND
or BLA, as applicable, and (iv) all other applicable regulatory requirements, in
accordance with procedures agreed between Corixa and Nordion. Nordion will
provide Corixa with the applicable Batch records, including without limitation,
a copy of any applicable Deviation or other investigatory reports and product
information sheet, in final form, and/or any other certificate required by the
applicable regulatory authorities for Release of each Batch of the Labeled Drug.
The format and routing of these documents are further described in the Quality
Policy

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Manual. Corixa may, in its reasonable discretion, withhold Release based upon
the contents of any of these records.

         5.3      Quality Control Program. [*].

         5.4      Compliance Standards.

                  (a)      Nordion Quality Policies. Throughout the term of this
Agreement, Nordion shall notify Corixa in advance of any material change in the
Nordion Quality Policies which directly has an impact on the Labeled Drug.
Further, Corixa, at its expense, shall have the right to access the Nordion
Quality Policies during Corixa's annual audit described in Section 5.12 (b) (ii)
for the purpose of verifying Nordion's compliance with the Nordion Quality
Policies.

                  (b)      Compliance with cGMPs, Nordion Quality Policies,
Legal Requirements or Regulatory Acts. Nordion shall be responsible for
identifying and implementing, in accordance with its obligations under Sections
4 and 5, any actions required to bring Nordion into compliance with cGMPs,
Nordion Quality Policies or any regulatory act or legal requirement imposed by
an applicable governmental entity with jurisdiction in the Territory. Subject to
Section 4.4(b)(ii), Nordion shall have the sole responsibility for reviewing
cGMPs, legal requirements and regulatory acts in order to identify and implement
any actions required for compliance therewith. Nordion shall implement any such
changes as promptly as practicable after the changes are adopted (but in no
event later than the effective date of such change), unless the effective date
falls after a termination of this Agreement for which notice has been previously
given.

                  (c)      Compliance with Health, Safety and Environmental
Guidelines. In the performance of its obligations under this Agreement, Nordion
shall comply with any and all regulatory acts or legal requirements imposed by
an applicable governmental entity with jurisdiction in the Territory related to
health, safety or the environment or Environmental Regulations. Nordion is
solely responsible for the safety and health of its employees and shall take
such actions as are necessary to protect its employees' safety and health,
including, without limitation, providing its employees with all required
information and training concerning any potential hazards involved in the
manufacture, packaging, storage and supply of the Labeled Drug and taking any
precautionary measures to protect its employees from any such hazards.

         5.5      Corixa Holds and Rejections. Corixa shall notify Nordion of
Corixa's investigation of a Nonconformity or a Deviation (and any related
report). Corixa will give Nordion any such notice within thirty (30) days after
receipt of such Labeled Drug by Corixa or Corixa's designee that received such
Labeled Drug. Corixa's notice shall state the basis for such investigation and
Corixa will be permitted to investigate such deviations and nonconformity.

         5.6      Deviation; Nonconformity. Labeled Drug, as well as
intermediate drug product related to the Labeled Drug which are in Nonconformity
or subject to a Deviation will be segregated from conforming products in a
manner consistent with cGMP, the Quality Policy Manual and the Nordion Quality
Policies. The existence of any Nonconformity and Deviations and their related
investigations will be reported to Corixa promptly in writing.

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         5.7      Complaints and Adverse Events.

                  (a)      Notification. Nordion shall notify Corixa as soon as
possible, but at least within one (1) business day of receipt or becoming aware
of information that may be an Adverse Event. Nordion shall in each successive
quarter notify Corixa of Complaints received by Nordion in the prior quarter
during the term of this Agreement.

                  (b)      Investigations. Nordion will cooperate and support
Corixa in its investigation of Complaints, Adverse Events, Deviations and
Nonconformities in a timely manner.

         5.8      Certain Labeled Drug Events.

                  (a)      Notification and Cooperation. In the event either
Party shall be required (or shall voluntarily decide) to initiate a recall,
withdrawal or field correction of, or a field alert report or comparable report
with respect to any Labeled Drug manufactured by Nordion pursuant to this
Agreement, whether or not such recall, withdrawal, field correction or field
alert report has been requested or ordered by any governmental body, the
initiating Party shall notify the other Party's most senior quality assurance
officer, and the Parties shall fully cooperate to implement the same.

                  (b)      Coordination of Efforts. In the event Nordion
believes that a recall, withdrawal, field correction, field alert report or
comparable report with respect to any Labeled Drug may be necessary and/or
appropriate, Nordion shall immediately notify Corixa. The Parties shall
cooperate with each other in determining the necessity and nature of such
action; provided, however, that Nordion shall take no action to effect the same
without the written concurrence of Corixa. If Corixa does not concur with any
recall, withdrawal, field correction, field alert report or comparable report
recommended by Nordion, then, without limiting any liability Corixa otherwise
has under this Agreement, Corixa shall be liable under this Section 5.8 for any
losses incurred by Nordion or Corixa that could have been avoided but for the
delay, except to any extent Nordion withheld material information or
misrepresented the material information upon which Corixa made its
determination.

                  (c)      Records and Recalls. Corixa and/or its designee shall
maintain records of all sales of Labeled Drug and customers sufficient to
adequately administer a recall, market withdrawal or correction for a period of
five (5) years after termination or expiration of this Agreement. Except as
required by law, Corixa and/or its designee shall serve as the sole point of
contact with the FDA or other applicable governmental entity or regulatory
authority concerning any recalls, market withdrawals or corrections with respect
to Labeled Drug.

         5.9      Reporting, Contacts and Statements. Corixa will be solely
responsible for communicating Complaints, Adverse Events and the results of
investigations related thereto, to the public and/or regulatory authorities. In
the event that Nordion is contacted by the public and/or regulatory authorities
regarding Complaints, Adverse Events or the results of investigations related
thereto, Nordion shall make no comment, unless otherwise required by law,
regulation or order and shall refer such inquiry to Corixa. Corixa will use
commercially reasonable efforts to keep Nordion appropriately informed prior to
any such communication with the public or authorities that relates to Nordion's
activities under this Agreement. In the event Corixa communicates any
Complaints, Adverse Events or the results of investigations related thereto to
the public and/or regulatory authorities which mentions Nordion by name or by
inference, Nordion shall be entitled to respond to such

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communication. With respect to any recall, withdrawal, field correction, field
alert report or comparable report related to any Labeled Drug, Corixa shall be
entitled to make contact with the applicable governmental body and/or regulatory
authority and shall be responsible for coordinating all of the necessary
activities in connection with any such recall, withdrawal, field correction,
field alert report or comparable report. Nordion shall collaborate with Corixa
on the content of any such statement. In the event that Nordion is required to
communicate with the FDA with respect to a recall of Labeled Drug or otherwise
regarding Labeled Drug, Nordion shall immediately notify Corixa of such
communication with the FDA.

         5.10     Regulatory Approvals.

                  (a)      Updates and Notices. Upon Nordion's reasonable
request, Corixa shall provide updates to Nordion of (i) the progress of clinical
development of the Labeled Drug as it relates to manufacturing operations; (ii)
the fact of any IND or BLA submissions to the FDA relating to Labeled Drug, and
(iii) copies of the applicable sections of any regulatory filings which
reference Nordion or Nordion activities. In addition, Corixa shall promptly
advise Nordion, at Nordion's request, in matters pertaining to U.S. regulatory
requirements relating to Nordion's activities hereunder. Corixa shall also
provide to Nordion reasonable advance notice of any regulatory submission
containing information or data provided by Nordion to Corixa that Corixa intends
and is permitted to disclose to regulatory agencies under this Agreement.
Nordion shall also provide to Corixa reasonable advance notice of any regulatory
submission containing information or data provided by Corixa to Nordion that
Nordion intends and is permitted to disclose to regulatory agencies under this
Agreement.

                  (b)      Regulatory Changes. Each Party shall promptly notify
the other of new or amended regulatory requirements of which it becomes aware
that are relevant to the manufacture of Labeled Drug under this Agreement and
that are required by the FDA, and any other applicable governmental entity in
the Territory, or other applicable laws or governmental regulations and shall
confer with each other and agree with respect to the best means to comply with
such requirements. Any changes required by the forgoing sentence that are to the
Corixa Equipment, Process or Specifications shall be paid for by Nordion,
subject to the provisions of Section 4.4(b)(ii) and the SOWs attached hereto as
Exhibit 7.

         5.11     Registrations, Listings, Authorizations and Approvals.

                  (a)      Labeled Drug. Corixa or its designee shall be
responsible for obtaining and maintaining such drug licenses, registrations,
listings, authorizations and approvals as the FDA or any other applicable
governmental entity may require to enable use of Labeled Drug in Clinical Trials
and marketing of Labeled Drug wherever such activities will occur. Nordion
shall, to the extent it has information in it possession, provide assistance to
Corixa in obtaining and maintaining all licenses, registrations, listings,
authorizations and approvals of any governmental entities necessary for the use
of Labeled Drug in Clinical Trials and marketing of Labeled Drug wherever such
activities will occur. Corixa and/or its designee shall serve as the point of
contact with the FDA and any other applicable governmental entity concerning
licenses, registration, authorizations or approvals required to use Labeled Drug
in Clinical Trials or market Labeled Drug, but may, as appropriate, request
Nordion's assistance with the FDA and/or other applicable governmental entity
communications.

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                  (b)      Drug Master Files. Nordion shall, at Nordion's
expense, update its Isotope Drug Master File with the FDA ("DMF"), as may be
required for the chemistry, manufacture and control ("CMC") section for the IND
or BLA for the Labeled Drug, or corresponding portions of any submission for a
license, registration, authorization or approval required by other applicable
governmental entities in the Territory for Clinical Trials or for marketing
Labeled Drug ("Territory DMF").. Upon Corixa's request, and subject to Nordion's
prior review and approval of the submission that references the DMF or Territory
DMF, which approval shall not be unreasonably withheld or delayed, Nordion shall
grant to Corixa a right of reference to such DMF or Territory DMF and shall
provide Corixa:

                           (i)      A letter of access to the DMF and the
Territory DMF allowing regulatory review of the DMF and the Territory DMF by the
FDA, Health Canada or equivalent agency in the Territory in conjunction with
Corixa's Labeled Drug regulatory submission; and

                           (ii)     Any information related to the Process
required for CMC purposes or for comparable purposes in the Territory. In the
event that Nordion is contacted by the FDA, Health Canada or equivalent agency
in the Territory regarding the DMF or Territory DMF to the extent it has an
impact on Labeled Drug, Nordion shall promptly provide Corixa with notice of
such contact and provide written confirmation to Corixa within five (5) business
days that Nordion received inquiries from the FDA, Health Canada or equivalent
agency in the Territory and shall advise Corixa of the estimated time and
proposed nature of Nordion's response. Nordion shall respond promptly to any and
all such inquiries from the FDA, Health Canada or equivalent agency in the
Territory.

                  (c)      Nordion Site. Nordion shall, at Nordion's expense,
obtain and maintain all necessary licenses, registrations, authorizations and
approvals, with respect to the Nordion Site, which are necessary to develop,
manufacture, handle, store, label, package, transport and deliver Labeled Drug
under cGMP conditions and other regulatory requirements, including without
limitation, the use and handling of radioactive materials and Nordion Site
licenses. Except with respect to correspondence relating directly to the DMF or
Territory DMF, Nordion shall provide Corixa with summaries or copies of any
correspondence sent from Nordion to governmental entities relating to Labeled
Drug at the time such correspondence is sent by Nordion, purged of Nordion
proprietary and/or confidential information and trade secrets. Nordion shall
provide Corixa with summaries or copies of any comments, responses, notices or
other correspondence received by Nordion from any governmental entity relating
to Labeled Drug within five (5) business days of receipt of such correspondence
by Nordion, purged of any Nordion proprietary information and/or trade secrets.

         5.12     Inspections.

                  (a)      By Governmental Entities.

                           (i)      Upon the request of any governmental entity
or any third party entity authorized by a governmental entity, such entity shall
have access to observe and inspect the Nordion Site and procedures used for the
storage of B1 Antibody for the Labeled Drug and the manufacture, testing,
storage or shipment of Labeled Drug, including without limitation, manufacturing
operations, and to audit such facilities for compliance with cGMP and/or other
applicable regulatory standards. To the extent it has advance notice, Nordion
shall give Corixa notice of any inspections or audits by a governmental entity
(or a third party authorized by a governmental entity) of the above-mentioned

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facilities or procedures within at least twenty-four (24) hours prior to the
commencement of said inspection or audit. In all events, Nordion shall provide
Corixa with a verbal summary of such inspection or audit at the end of each day
in which inspection activity occurs and a written report within five (5)
business days of the inspection or audit. Such summary and report will be
subject to the confidentiality requirements of Section 14.

                           (ii)     Nordion shall notify Corixa within five (5)
business days of any written or oral inquiries, notifications with respect to
inspection activity by any governmental entity (or any third party authorized by
a governmental entity) on matters that could adversely affect, whether directly
or indirectly, Nordion's ability to perform under this Agreement. Nordion shall
provide a reasonable description to Corixa of any such governmental inquiries,
notifications or inspections promptly (but in no event later than five (5)
business days) after such visit or inquiry. Nordion shall furnish to Corixa
within five (5) business days after receipt, a summary of any report or
correspondence issued by the governmental entity (or a third party authorized by
a governmental entity) in connection with such visit or inquiry, including
without limitation, any FDA Form 483 (List of Inspectional Observations) or
warning letter with respect to Labeled Drug. Nordion shall also furnish to
Corixa not later than five (5) business days after the time it provides such to
a governmental entity, summaries of any and all proposed responses or
explanations relating to the items set forth above (each a "Proposed Response"),
in each case purged only of trade secrets or other Nordion Confidential
Information. After the filing of a response with the appropriate governmental
entity, Nordion shall notify Corixa of any further oral and/or written contacts
with the governmental entity or its representative relating to Nordion's
production of Labeled Drug.

                           (iii)    Nordion shall promptly rectify or resolve
any deficiencies noted by a governmental entity or its third party
representative in a report or correspondence issued to Nordion, provided such
deficiency is not related to any new or amended regulatory requirement as
described in Section 5.10(b) in which case Section 5.10(b) applies.

                  (b)      By Corixa, its Affiliates and/or Representatives.
Corixa, its Affiliates or representatives as mutually agreed (subject to
execution of a confidentiality agreement in the form attached hereto as Exhibit
5.12(b)), shall have reasonable access to the Facility and related Labeled Drug
procedures for the purpose of:

                           (i)      At least once per calendar quarter, and more
frequently in Corixa's reasonable discretion, observing the Process relating to
Labeled Drug; and

                           (ii)     Annually auditing the Facility for
compliance with Specifications, cGMP and other applicable regulatory
requirements and standards relating to the Labeled Drug. Such audit shall not
exceed three (3) days in duration unless mutually agreed otherwise.

                  (c)      [*].

[*].

         5.13     Records and Reports. Nordion shall maintain all records
necessary to evidence compliance with (i) all applicable laws, regulations and
other requirements of applicable governmental

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entities in the Territory relating to the manufacture of Labeled Drug; (ii)
relevant sections of the applicable IND or BLA relevant to Labeled Drug and
corresponding licenses, registrations, authorizations or approvals for foreign
jurisdiction(s) as advised by Corixa and agreed between the Parties; (iii) the
Specifications and Isotope Specifications; and (iv) material obligations and
performance under this Agreement. All such records shall be maintained at
Nordion for at least that amount of time as required by law, regulation or cGMP.
Prior to destruction of any record after such time, Nordion shall give written
notice to Corixa upon which Corixa shall have the right to request that Nordion
maintain such records in an off-site storage facility for such longer period as
Corixa requests, provided that Corixa pays all reasonable costs associated with
such off-site storage. Upon Corixa's prior written request and at Corixa's sole
expense, Nordion agrees to provide Corixa with access to such records that are
stored at an off-site facility. Nordion will provide, on a quarterly basis,
manufacturing overview reports for discussion and review with Corixa at
quarterly manufacturing meetings.

6.       Failure to Supply.

         6.1      Batch Default.

                  (a)      Definition of Delay. For purposes of this Agreement,
"Delay" shall mean a failure by Nordion to make delivery, pursuant to the
provisions of Section 3.2(c), of a Batch which meets Specifications and shall
not include any such failure caused by an act or omission of Corixa or its
agents or representatives. For the avoidance of doubt, such a failure of
delivery with respect [*] within a Batch shall constitute a Delay with respect
to such Batch.

                  (b)      Definition of Recall. For purposes of this Agreement,
"Recall" shall mean a recall or market withdrawal or correction of Labeled Drug
due to Nordion's error, factors within Nordion or its agent's control, including
without limitation, Nordion or its agent's handling, manufacture, packaging or
storage of Labeled Drug, the Labeled Drug's failure to meet Specifications
(provided such failure to meet Specifications is not caused by the B1 Antibody,
the CD-20 Antigen Cells or an act or omission of Corixa or its agents or
representatives) or to the failure of Isotope used in the manufacture of Labeled
Drug to meet the Isotope Specifications.

                  (c)      Definition of Delay Cost. For purposes of this
Agreement, "Delay Cost" shall mean, for any Batch which is subject to a Delay,
the sum of (i) the actual, documented cost [*] in such Batch and [*]; and (ii)
an amount equal to the [*] of: (v) the product of [*] (for a Delay of [*] or
less) or [*]) (for a Delay of more than [*]) multiplied by the Scheduled Vials;
or (w) [*] per Batch of Labeled Drug subject of a Delay. The [*] provided for in
Section 6.1(c) (ii) above shall automatically increase once per year on each
anniversary of the Effective Date as follows: (x) on the first anniversary of
the Effective Date by an amount equal to the [*] of the percentage increase in
CPI in the previous twelve (12) month period and [*] percent [*] (y) on the
second anniversary of the Effective Date by an amount equal to the [*] of the
percentage increase in CPI in the previous twelve (12) month period and [*]
percent [*] and (z) on each of the third and following anniversaries of the
Effective Date of the Agreement by an amount equal to the [*] of the percentage
increase in CPI in the previous twelve (12) month period and [*].

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         6.2      Remedies for Delay.

                  (a)      Dosimetric or Therapeutic Supply. Notwithstanding
anything in this Agreement to the contrary, Corixa shall not be required to pay
for any Batches which are not delivered pursuant to Section 3.2(c) regardless of
whether such Batch is manufactured; provided, however, if Corixa would otherwise
be required to pay for a Batch which Nordion attempts to deliver pursuant to
Section 3.2(c)(i) and such Batch would have been successfully delivered but for
a failure of the Carrier to arrive after Nordion contacted such Carrier in a
timely manner, Corixa shall pay for such Batch. In the event a dosimetric or
therapeutic Batch is the subject of a Delay of less than or equal to [*], the
purchase price for the affected Batch, replacement Batch or next Batch shall be
reduced by the sum of [*] percent [*] of such purchase price plus the Delay
Costs. In the event a dosimetric or therapeutic Batch is the subject of a Delay
of more than [*] but less than [*], the purchase price for the affected Batch,
replacement Batch or next Batch shall be reduced by the sum of [*] percent [*]
of such purchase price plus the Delay Costs. In the event a dosimetric or
therapeutic Batch is the subject of a Delay of more than [*], the purchase price
for the affected Batch, replacement Batch or next Batch shall be reduced by the
sum of [*] percent [*] of such purchase price plus the Delay Costs. The
discounts set out in this section are not cumulative.

                  (b)      Termination. In the event that either: (i) [*] or
more dosimetric Batches are the subject of a Delay in any [*]; or (ii) [*] or
more therapeutic Batches are the subject of a Delay in any [*], Corixa may, at
its option, terminate this Agreement upon [*] days written notice at any time
within [*] days of the date of the last Delay giving rise to Corixa's right to
terminate.

                  (c)      Reduction in Minimums. Corixa's minimum purchase
commitments described at Section 3.1(g) for any given [*] period will be reduced
by [*] for each dosimetric Batch which is subject to a Delay enduring more than
[*]. For each therapeutic Batch which is subject to a Delay enduring more than
[*], the minimum purchase commitment for the [*] period in which such
therapeutic Batch Delay occurs, will be reduced by [*].

         6.3      Remedies for Recall. In the event of a Recall, Corixa shall be
relieved of any obligation to pay the purchase price for such Batch, and Nordion
shall indemnify Corixa for the following out-of-pocket costs incurred in
connection with such Recall: (i) Delay Costs; (ii) the out of pocket cost of
return of Labeled Drug to Nordion (if applicable); (iii) Isotope costs incurred
in connection with any Recalled Batch under the Iodine Supply Agreement for
Iodine used in the production of the Batch subject of the Recall; and (iv) the
actual cost to Corixa of B1 Antibody and CD-20 Antigen Cells. In the event of a
Recall, [*].

7.       Statements of Work. The Parties are currently performing under certain
signed SOWs. The Parties acknowledge and agree that, unless otherwise agreed by
the Parties, no additional engineering, development or other work will be
required to implement the terms of this Agreement other than that work required
by the SOWs listed on Exhibit 7. If Nordion and Corixa cannot agree on a SOW
within [*] of Corixa's receipt of Nordion's proposal, the matter shall be
referred to the executive steering committee currently constituted and born from
past practice between Corixa and Nordion with respect to executive management of
Labeled Drug operations.

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8.       Maintenance, Facility Use and Asset Ownership.

         8.1      Maintenance.

         (a)      Prior to the implementation and completion of the work with
                  respect to each piece of equipment set out in the following
                  [*] SOWs[*], as identified in Exhibit 7 [*] (i) Nordion shall
                  in accordance with cGMPs [*] repair, maintenance and service
                  contracts of all equipment excluding the equipment subject of
                  a [*] and (ii) Corixa and Nordion shall, [*] of repair,
                  maintenance and service contracts of those pieces of equipment
                  subject of a [*].

                  In the event that the [*] is agreed to by Corixa and Nordion
                  prior to [*], the [*] set out in item (ii) above shall only
                  continue until the completion of the [*] or [*], whichever
                  occurs first. In the event that agreement is not reached on a
                  [*] prior to [*] that agreement is not reached, [*] set out in
                  item (ii) above shall be [*]. Corixa shall not, pursuant to
                  item (ii) above, be liable for the expense of repair,
                  maintenance and service contracts in excess of [*] United
                  States dollars [*] in each [*].

                  In addition, Nordion and Corixa shall [*] of implementation
                  and completion of [*]. For the avoidance of doubt all work
                  carried out under an applicable [*] shall be in accordance
                  with the terms of that [*].

                  The labor rate applicable by Nordion for the purpose of this
                  section shall be [*] United States dollars [*] per hour.

         (b)      After completion and implementation of the work with respect
                  to each piece of equipment in a [*] under the [*], Nordion
                  shall in accordance with cGMPs as of such date, bear the
                  expense of repair, maintenance and service contracts of such
                  piece of equipment.

         8.2      Facility Use.

                  (a)      Radiolabeling B1 Antibody. The Facility shall use the
Process to radiolabel B1 Antibody in accordance with cGMP and all other
requirements set forth in this Agreement in those Batch sizes according to the
I-131 quantity set forth in Exhibit 9.1.

                  (b)      Restrictions on Use of Facility. During the term of
this Agreement, Nordion may not use those portions of the Facility that are
solely dedicated to the manufacturing or packaging of Labeled Drug for any
purpose other than producing Labeled Drug for Corixa or for conducting
additional experiments at Corixa's direction per an agreed upon SOW.

                  (c)      Facility Validated. Nordion acknowledges and agrees
that the Process has been Validated at the Facility and that Nordion is capable
of producing the Labeled Drug in accordance with the Process. Nordion shall be
responsible for all cost arising from producing the Labeled Drug in accordance
with the Validated Process.

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         8.3      Corixa Equipment. Subject to Sections 8.4,11.7(b) and/or as
otherwise set out in this this Agreement, all right, title and interest in and
to the Corixa Equipment shall belong to and remain the property of Corixa.
Subject to the foregoing and Section 8.4, Nordion shall own all other assets
purchased under the Previous Agreements.

         8.4      Hot Cell Ownership. Nordion has purchased the Hot Cells on
behalf of Corixa. Until transfer of the Hot Cells to Nordion in accordance with
this Agreement, Corixa shall retain all right, title and interest in and to such
Hot Cells; provided that Nordion shall have the exclusive right to use the Hot
Cells for the sole purpose of producing and supplying Labeled Drug to Corixa
pursuant to this Agreement. Corixa represents and warrants that the Hot Cells
are not encumbered, and shall, during the term of this Agreement, remain free
and clear of any and all encumbrances, including, without limitation, mortgages,
charges and liens. Corixa shall use commercially reasonable efforts to ensure
that no effective financing statement or other instrument similar in effect
covering all or any part of the Hot Cells is on file in any recording office. In
the event of termination (for any reason ) or expiration of this Agreement, or
effective May 31, 2004, whichever is earlier, in consideration of $1.00 and
other valuable consideration, the receipt and sufficiency of which are hereby
acknowledged, Corixa hereby transfers to Nordion (without any further formality
of conveyance) ownership of the Hot Cells. During the term of this Agreement,
the Hot Cells shall be used by Nordion for the purpose of producing and
supplying Labeled Drug to Corixa in accordance with this Agreement. Until such
time as Corixa has transferred the Hot Cells to Nordion, Nordion is hereby
granted a continuing first priority security interest in the Hot Cells securing
the obligation of Corixa to effect transfer of the Hot Cells to Nordion and the
obligation of Corixa to not create any interest in the Hot Cells that would
constitute an encumbrance, charge, lien or other impediment to the transfer of
the Hot Cells to Nordion. The security interest in the Hot Cells, effective
January 1, 1996, under the Facilities Agreement continues under this Agreement
and is perfected by the continuous and ongoing possession of the Hot Cells by
Nordion. Notwithstanding the applicable law set out in this Agreement, the laws
of Ontario, Canada shall govern the security interest created herein.

9.       Payments.

         9.1      Pricing. The purchase price for each Batch of Labeled Drug
that is produced by Nordion in accordance with a Firm Order and that meets
Specifications is provided in Exhibit 9.1. Upon expiration or early termination
of the Iodine Supply Agreement, the purchase price for each Batch of Labeled
Drug shall be adjusted as provided for in Exhibit 9.1. In the event that Corixa
purchases more than [*] Batches in a given [*] period, the Parties will meet to
discuss changing the per-Batch purchase price for the Labeled Drug.

         9.2      Cancellation Fees. Subject to any additional payments set
forth in this Section 9.2, Corixa may cancel a scheduled Batch at any time prior
to the Scheduled Batch Completion Date. In the event of a cancellation by Corixa
of a Batch subject to a Firm Order during the period prior to the [*] of the
Commercial Supply, Corixa agrees to pay Nordion a fee of [*] percent [*] of the
applicable Batch price. Without limiting Corixa's obligation with respect to the
minimum purchase commitments under this Agreement, in the event that Corixa
cancels a Batch subject to a Firm Order after the [*] of Commercial Supply,
Corixa, subject to a reconciliation as set out below, shall pay Nordion a fee of
[*] percent [*] of the applicable Batch price. [*]. The cancellation fees
referenced in this Section 9.2 shall

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be invoiced by Nordion on an ongoing basis, and a reconciliation shall occur at
the end of each successive [*] period after the [*] of the commencement of
Commercial Supply. [*].

         9.3      Invoicing and Payment.

                  (a)      Nordion. No more frequently than monthly, Nordion
will provide Corixa with an invoice for the purchase price for each Batch of
Labeled Drug delivered to Corixa or Corixa's designees and maintenance cost and
expense as per Section 8.1, not previously invoiced. Such invoices will be due
and payable within [*] of receipt by Corixa.

                  (b)      Corixa. No more frequently than monthly, Corixa will
provide Nordion with an invoice for any amounts payable to Corixa pursuant to
this Agreement. Such invoices will be due and payable within [*] of receipt by
Nordion.

         9.4      Price Increase. All amounts due to Nordion pursuant to this
Agreement shall be payable in U.S. dollars. Nordion may increase the amounts
payable from Corixa to Nordion hereunder no more than once per year as follows:
(a) on the [*] of the Effective Date by an amount equal to the [*] of the
percentage increase in CPI in the previous twelve (12) month period and [*]
percent [*] (b) on the [*] of the Effective Date by an amount equal to the [*]
of the percentage increase in CPI in the previous twelve (12) month period and
[*] percent [*] and (c) on each of the [*] and [*] of the Effective Date of this
Agreement by an amount equal to the [*] of the percentage increase in CPI in the
previous twelve (12) month period and [*].

         9.5      Supporting Documentation. Any amounts requested or invoiced by
Corixa to Nordion, including without limitation, other payments, credits or
price reductions provided due to Delays or Recalls, shall be supported by
accompanying documentation in support of the amounts invoiced or claimed.

         9.6      Record Retention; Audits.

                  (a)      Record Keeping. Nordion shall keep accurate books and
accounts of records in connection with amounts invoiced to Corixa under this
Agreement (excluding fixed price items agreed to by Corixa and Nordion) or any
SOW (excluding fixed price items agreed to by Corixa and Nordion) in sufficient
detail to permit accurate determination of all figures necessary for
verification of all compensation invoiced to Corixa hereunder or thereunder.
Nordion shall maintain such records for a period of three (3) years after the
end of the year in which they were generated.

                  (b)      Audits. Upon reasonable notice to Nordion, Corixa
shall have the right to have an independent certified public accountant,
selected by Corixa and acceptable to Nordion, acting reasonably, to audit
Nordion's records pertaining to amounts invoiced to Corixa. If the Parties agree
that Nordion is to provide goods or services at a fixed price (as opposed to on
a time and materials basis) such items shall not be subject to audit. Such audit
shall take place during normal business hours; provided, however, that such
audit shall not take place more frequently than [*] and shall not cover such
records for more than the preceding [*]. Such audit shall be at Corixa's
expense; provided, however, that if such audit yields a discrepancy of [*] or
greater in Nordion's favor, [*] the amount of over-payment within thirty (30)
days of the final audit report. Upon reasonable notice to Corixa, for

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the purposes of sections 6.1 (c) and 6.3, Nordion may require and Corixa shall
provide a statement executed by Corixa's Chief Financial Officer certifying as
true and correct any costs claimed from Nordion pursuant to such sections.

10.      Intellectual Property.

         10.1     Licensing.

                  (a)      Limited License to Nordion. Corixa hereby grants to
Nordion a non-exclusive, nontransferable, non-sublicensable, royalty-free
license during the term of this Agreement to use data, information and
technology provided by Corixa to Nordion that relates to B1 Antibody
radiolabeling, for the limited purpose of assisting Nordion to carry out its
obligations under this Agreement. The data, information and technology licensed
hereunder shall be Corixa Confidential Information as that term is used at
Section 14.1 of this Agreement.

                  (b)      Limited License to Corixa. Nordion hereby grants to
Corixa a worldwide, nonexclusive, royalty free, perpetual license, with right to
sublicense, to use any Nordion IP used in the process of manufacturing Labeled
Drug as disclosed in the BLA, for the sole and limited purpose of selling,
having sold, distributing, having distributed, manufacturing and having
manufactured Isotope radiolabeled B-1 Antibody, except for any Nordion IP
related to [*].

                  (c)      No Other Grant. It is agreed that disclosure of data,
information or technology by Nordion or Corixa to the other during the term of
this Agreement shall not, except to the extent granted herein, constitute any
grant, option or license under any patent, technology or other rights held by
Nordion or Corixa.

                  (d)      Licensing Related Indemnification. Corixa shall
defend, indemnify and hold Nordion, its Affiliates and their respective
directors, officers, employees and agents, harmless from and against any
damages, claims, liabilities and expenses, (including without limitation,
reasonable attorney's fees) resulting from a claim or suit arising out of any
proceeding (including without limitation, any proceeding claiming infringement
of patents or other proprietary rights of third parties) instituted by a third
party, other than an Affiliate or licensee of Nordion, based on Corixa's or any
of its sublicensees' use of the Nordion IP licensed to Corixa pursuant to
Section 10.1(b). Nordion shall defend, indemnify and hold Corixa, its Affiliates
and their respective directors, officers, employees and agents, harmless from
and against any damages, claims, liabilities and expenses, (including without
limitation, reasonable attorney's fees) resulting from a claim or suit arising
out of any proceeding (including without limitation, any proceeding claiming
infringement of patents or other proprietary rights of third parties) instituted
by a third party, other than an Affiliate or licensee of Corixa, based on
Nordion's or any of its sublicensees' use of the Corixa IP licensed to Nordion
pursuant to Section 10.2(d).

         10.2     Ownership.

                  (a)      Nordion IP. The Parties acknowledge and agree that as
between the Parties, the Nordion IP is and shall remain the property of Nordion.

                  (b)      Corixa IP. The Parties acknowledge and agree that as
between the Parties, the Corixa IP is and shall remain the property of Corixa.

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                  (c)      Technology Developed Under this Agreement or Previous
Agreements. Nordion agrees and Corixa acknowledges that any and all ideas,
improvements, inventions and works of authorship, and any and all intellectual
property rights in any of the foregoing, conceived, written, created or first
reduced to practice in the performance of this Agreement, or the Previous
Agreements, except to the extent that it embodies the Background Technology or
improvements to the Background Technology, shall be the sole and exclusive
property of Corixa. Except as set forth in this Section 10.2, Corixa is and
shall be vested with all right, title and interest, including without
limitation, any intellectual property rights, in such ideas, improvements,
inventions and works of authorship. Nordion hereby assigns to Corixa all right,
title and interest in and to any and all such ideas, improvements, inventions
and works of authorship.

                  (d)      Additional Limited License to Nordion. Corixa hereby
grants to Nordion a non-exclusive, [*], worldwide, royalty-free, perpetual
license to exploit all ideas, improvements, inventions and works of authorship
assigned to or vested in Corixa as described in Section 10.2(c) for any
application, except the development or manufacture of [*].

         10.3     Corixa Proprietary Information. All data, information or
technology supplied to Nordion by Corixa to assist Nordion in carrying out its
obligations hereunder or under the Previous Agreements shall remain the property
of Corixa and shall be returned by Nordion to Corixa upon expiration or early
termination of this Agreement.

         10.4     Patent Applications. Nordion shall execute all papers and
documents, including without limitation, patent applications, invention
assignments and copyright assignments, and otherwise shall assist Corixa as
reasonably required to perfect in Corixa the rights, title and other interests
in Nordion's work product expressly granted to Corixa under this Agreement.
Reasonable costs related to such assistance, if required, shall be paid by
Corixa.

11.      Term and Termination.

         11.1     Term. The term of this Agreement shall commence upon the
Effective Date, and unless terminated earlier or extended as provided hereunder,
shall expire seven (7) years thereafter (the "Initial Term").

         11.2     Extension of Term. The term of this Agreement may be extended
for an additional three (3)-year period (the "Extended Term"), at either
Parties' request following the third anniversary of the Effective Date, by
providing written notification that the requesting Party wishes to extend the
term of this Agreement to the non-requesting Party not less than two (2) years
prior to the expiration of the Initial Term. The non-requesting Party shall have
one hundred and eighty (180) days from the date of receipt, to agree to the
Extended Term, otherwise the Agreement will terminate at the end of the Initial
Term. Any notice given pursuant to this Section 11.2 shall be made to the Chief
Executive Officer and General Counsel of the non-requesting Party and shall be
sent via certified mail with a return receipt requested.

         11.3     Termination by Corixa. Corixa may terminate this Agreement for
convenience at any time on or after the [*] of the Effective Date. Such notice
of termination shall provide Nordion at least [*] prior written notice. In the
event Corixa elects to terminate under this Section 11.3, Corixa shall pay
Nordion the applicable fee, as provided below, on the date such termination
becomes effective. If Corixa's termination of this Agreement is effective on the
[*] of the Effective Date, Corixa shall pay

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Nordion a fee of [*] US dollars [*] Thereafter such fee shall be reduced by [*]
US dollars [*] per year as follows: if Corixa's termination of this Agreement is
effective during the [*] year of this Agreement, the fee shall be [*] US dollars
[*]; if Corixa's termination of this Agreement is effective during the [*] year
of this Agreement, the fee shall be [*] US dollars [*] if Corixa's termination
of this Agreement is effective during the [*] year of this Agreement, the fee
shall be [*] US dollars [*] and if Corixa's termination of this Agreement is
effective during the [*] year of this Agreement, the fee shall be [*] US dollars
[*] After the [*] year of the Agreement, there shall be no further termination
fee.

         11.4     Termination for Breach. This Agreement may be terminated by
either Party in the event of the material breach by the other Party of the terms
and conditions herein; provided, however, the other Party shall first give to
the breaching Party written notice of the proposed termination of this Agreement
(a "Breach Notice"), specifying the grounds therefor. An event of material
breach by Nordion shall include without limitation, a failure by Nordion to meet
the obligations as set forth in Section 4.1. Upon receipt of the Breach Notice,
the breaching Party shall have sixty (60) days to respond by curing such breach
within such cure period (or thirty (30) days with respect to failure by Corixa
to pay any amounts hereunder when due, other than with respect to those amounts
which Corixa in good faith disputes are due to Nordion). If the breaching Party
does not cure such breach, the other Party may immediately terminate this
Agreement. Termination of this Agreement pursuant to this Section shall not
affect any other rights or remedies which may be available to the non-breaching
Party. In the event of material breach by Corixa which is not remedied in
accordance with this Section 11.4, Nordion shall be entitled to suspend supply
of Labeled Drug in addition to any other recourse it may have.

         11.5     Termination for Failure to obtain BLA Approval. This Agreement
may be terminated by either Party in the event that regulatory approval by the
FDA for the commercial sale of Labeled Drug does not occur by [*].

         11.6     Termination for Insolvency. A Party may terminate this
Agreement upon the occurrence of either of the following:

                  (a)      Involuntary Bankruptcy Filing. The other Party is
subject to the entry of a decree or order for relief by a court having
jurisdiction in the premises in respect of such Party in an involuntary case
under the Federal Bankruptcy Code in the United States of America or the
Bankruptcy and Insolvency Act in Canada, as now constituted or hereafter
amended, or any other applicable national, federal or state insolvency or other
similar law and the continuance of any such decree or order unstayed and in
effect for a period of sixty (60) consecutive days; or

                  (b)      Voluntary Bankruptcy Filing. The filing by the other
Party of a petition for relief under the Federal Bankruptcy Code in the United
States of America or the Bankruptcy and Insolvency Act in Canada, as now
constituted or hereafter amended, or any other applicable federal or state
insolvency or other similar law.

         11.7     Consequences of Expiration or Early Termination.

                  (a)      Post-Expiration/Termination Supply. Upon expiration
or early termination of this Agreement, Nordion (except if the Agreement is
terminated by Nordion due to material breach by

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Corixa pursuant to Section 11.4 or termination for bankruptcy pursuant to
section 11.6, in which case Nordion may elect to discontinue manufacture and
supply of Labeled Drug) shall manufacture and supply, and Corixa shall purchase
in accordance with the provisions hereof (provided that Nordion is able to
manufacture Labeled Drug and is not prevented from manufacturing or supplying
Labeled Drug for regulatory reasons or Force Majeure), any and all amounts of
Labeled Drug ordered pursuant to a Firm Order by Corixa prior to the date on
which such notice of termination is given; provided, however, that Corixa may
cancel any such order and pay a cancellation fee if required by Section 9.2 of
this Agreement.

                  (b)      Post-Expiration/Termination Rights and Obligations.
Upon expiration or termination of this Agreement for any reason, including,
without limitation, termination pursuant to Sections 6 (Failure to Supply), 11.3
(termination by Corixa for convenience), 11.4 (breach), 11.5 (BLA non-approval),
11.6 (bankruptcy) or 16.8 (Force Majeure), in addition to the respective rights
of each Party contained in this Agreement: (i) Nordion shall be entitled to
receive and Corixa shall pay all amounts due and owing by Corixa, [*] by Corixa
for all amounts Nordion owes to Corixa; (ii) Nordion shall, within seventy-five
(75) days after termination or expiration (subject to decontamination and/or
disposal (if applicable)), return, except as provided below, the Corixa
Equipment in Nordion's possession, provided that the transfer, decontamination
and/or disposal costs of the Corixa Equipment shall be at Corixa's cost and
expense unless the termination is by Corixa pursuant to Sections 6, 11.4 or
16.8, in which case Nordion shall pay for such transfer, decontamination and/or
disposal costs; (iii) Nordion shall, within one hundred and twenty (120) days
after termination or expiration, [*] (subject to any regulatory requirement to
the contrary), excluding Nordion IP related [*] provided that preparation of the
documents for delivery to Corixa in this subitem (iii) shall be at Corixa's cost
and expense, unless the termination is by Corixa pursuant to Section 6, 11.4 or
16.8, in which case Nordion shall bear such costs, (iv) Nordion shall receive or
retain ownership of the Hot Cells in accordance with Section 8.4; (v) Nordion
shall return the BLA to Corixa, and (vi), Nordion shall return to Corixa all
remaining B1 Antibody and CD-20 Antigen Cells; provided that such transfer shall
be at Corixa's cost and expense unless the termination is by Corixa pursuant to
Section 6, 11.4 or 16.8, in which case Nordion shall pay for such transfer.
Notwithstanding the foregoing, Nordion shall, for a period of one (1) year after
termination or expiration of this Agreement, as soon as reasonably practicable
but in no event later than thirty (30) days after receipt of written notice from
Corixa, deliver to Corixa a copy of those records, reports and other documents
within Nordion's possession or control that are required by the regulatory
agency to be delivered or maintained by Corixa in order for Corixa to remain in
compliance with applicable regulatory requirements in the Territory. If Corixa
fails to acknowledge its intent to take delivery of the Corixa Equipment, B1
Antibody or CD-20 Antigen Cells, within thirty (30) days of the receipt of
Nordion's notice of intention to ship such equipment, B1 Antibody, or CD-20
Antigen Cells and/or Corixa does not accept such shipment(s), all right, title
and interest in and to such equipment shall immediately transfer to Nordion and
Nordion shall destroy all B1 Antibody and CD-20 Antigen Cells in its possession
or control.

                  (c)      Survival. Upon expiration or termination of this
Agreement, any claims or causes of action arising hereunder prior to such
expiration or termination together with the rights and obligations of the
Parties under Sections 1, 4.2, 5.7, 5.8, 5.9, 5.13, 8.3, 8.4, 9.6, 10.1 (b), (c)
and (d), 10.2, 10.3, 10.4, 11.3, 11.4, 11.7, 12, 13.1, 13.2, 13.3, 13.4, 13.5,
13.6, 14, 15 and 16 shall survive such expiration or termination in accordance
with their terms.

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12.      Representations, Warranties and Disclaimers.

         12.1     Corixa. Corixa represents and warrants and covenants that:

                  (a)      B1 Antibody and CD-20 Antigen Cells. The B1 Antibody
and CD-20 Antigen Cells when supplied to Nordion shall (i) be manufactured in
accordance with cGMP and all applicable FDA regulations, including, without
limitation, the submission of appropriate regulatory documents, (ii) not be
misbranded or otherwise of a nature that may not be introduced into United
States interstate commerce, and (iii) meet the specifications respectively set
out in Exhibit 1.6 and 1.16;

                  (b)      Corixa IP. Except as set forth in Exhibit 12.1, as of
the Effective Date and to Corixa's best information and belief, (i) Corixa is
the owner or licensee of Corixa IP used in connection with this Agreement, (ii)
the Corixa IP used in connection with this Agreement does not infringe any
patents, copyright or other industrial or intellectual property rights of third
parties, (iii) Corixa has the right to grant the license set forth in Section
10.1 and the right to permit Nordion to use the Corixa IP used in connection
with this Agreement to carry out Nordion's obligations as contemplated herein,
and (iv) Corixa has not received any notice or adverse claim of infringement of
any patent contained in the Corixa IP used in connection with this Agreement;
and

                  (c)      Infringement. Except as set forth in Exhibit 12.1, as
of the Effective Date, to the best of Corixa's knowledge, there are no
intellectual property rights, including, without limitation, valid United States
patents, that would be infringed by the manufacture, use or sale of Labeled Drug
or the use of the Process. Notwithstanding the preceding sentence, Corixa makes
no warranty with respect to intellectual property rights relating to any
processes performed by Nordion hereunder except for that portion of any process
contributed by Corixa.

         12.2     Nordion. Nordion represents and warrants and covenants that:

                  (a)      Labeled Drug. Provided Corixa is in compliance with
its warranty under Section 12.1, and provided the Labeled Drug is not subject to
misuse, abuse or improper storage following delivery, the Labeled Drug,
including, without limitation, any labeling and other packaging for the Labeled
Drug, for the period from the date of manufacture to the expiry date set out on
each vial of Labeled Drug, (i) will conform to the Specifications, (ii) has been
manufactured, handled, stored, labeled, packaged and delivered in accordance
with the Specifications and applicable standard operating procedures and this
Agreement, (iii) has been manufactured, handled, stored, labeled, packaged and
delivered in accordance with cGMP and all other applicable laws, regulations and
other requirements of all applicable governmental entities in the Territory,
(iv) has been manufactured consistent with relevant sections of the IND or BLA,
as applicable, and corresponding licenses, registrations, authorizations or
approvals for Labeled Drug for each foreign jurisdiction, as previously advised
by Corixa and agreed by the Parties, and (v) will not be (A) misbranded by
Nordion within the meaning of the FD&C Act, or (B) of a nature that may not be
introduced into United States interstate commerce. Furthermore, Nordion
represents, warrants and covenants that it will comply with all Environmental
Regulations.

                  (b)      Nordion IP. As of the Effective Date, to Nordion's
best information and belief, (i) Nordion is the owner of the Nordion IP used in
connection with this Agreement, (ii) the Nordion IP used in connection with this
Agreement does not infringe any patents, copyright or other industrial or

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<PAGE>

intellectual property rights of third parties, (iii) Nordion has the right to
use the Nordion IP used in connection with this Agreement to carry out its
obligations as contemplated herein, (iv) Nordion has not received any notice of
adverse claim or infringement of any patent relating to the Nordion IP used in
connection with this Agreement, and (v) there is no action or proceeding pending
or insofar as Nordion knows or ought to know, threatened against Nordion before
any court, administrative agency or other tribunal which might have a material
adverse effect on Nordion's business.

                  (c)      Destroyed or Returned Items. Exhibit 1.28 provides a
complete and accurate list of all items and equipment owned by Corixa which are
located at the Nordion Site. Exhibit 12.2(c) contains a complete and accurate
list of items or equipment, that as of the Effective Date, (i) were owned by
Corixa but which have been destroyed or (ii) are owned by Corixa and have been
returned to Corixa by or on behalf of Nordion.

         12.3     Mutual. Each Party hereby represents and warrants to the other
that this Agreement is legal and valid and the obligations binding upon such
Party are enforceable in accordance with their terms, and that the execution,
delivery and performance of this Agreement does not conflict with any agreement,
instrument or understanding, oral or written, to which such Party may be bound,
nor to its knowledge violate any law or regulation of any court, governmental
body or administrative or other agency having jurisdiction over it.

         12.4     No Other Warranties. Except as expressly provided in this
Agreement, neither Party makes any representations or warranties to the other
Party and each Party disclaims all other warranties, whether express or implied,
statutory or otherwise, including without limitation, any implied warranties of
merchantability or fitness for a particular purpose.

13.      Indemnification.

         13.1     By Corixa.

                  (a)      Indemnification Obligation. Subject to Nordion's
compliance with Section 13.4, Corixa agrees to indemnify, defend and hold
Nordion and its Affiliates and their respective directors, officers, employees
and agents harmless from and against any damages, claims, liabilities and
expenses, including, without limitation, reasonable attorneys' fees, resulting
from any third party claims or suits ("General Claims Against Nordion") arising
out of (i) the use, handling, shipment, marketing or sale of Labeled Drug, (ii)
Corixa's breach of any of its covenants, warranties or representations
hereunder, or (iii) Corixa's negligent acts or omissions or willful misconduct.

                  (b)      Exceptions to Indemnification Obligations.
Notwithstanding the foregoing, Corixa will not be required to indemnify, defend
or hold Nordion or its Affiliates and their respective directors, officers,
employees and agents harmless from and against any General Claims Against
Nordion to the extent arising out of (i) Nordion's breach of any of its
warranties or representations hereunder; (ii) Nordion's negligent acts or
omissions or willful misconduct; (iii) any failure by Nordion to manufacture
Labeled Drug to meet the Specifications; (iv) any failure of Nordion to
manufacture, handle, store, label, package, or transport Labeled Drug in
accordance with cGMP or any other applicable laws, regulations or other
requirements of any applicable governmental entity in the Territory; or (v) any
failure of Nordion to manufacture Labeled Drug consistent with the applicable
sections of the IND or BLA, as applicable, and any corresponding licenses,
registrations, authorizations

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<PAGE>

or approvals in the Territory. Notwithstanding anything in this Section 13.1,
General Claims Against Nordion shall not include IP Claims Against Nordion.

         13.2     By Nordion.

                  (a)      Indemnification Obligation. Subject to Corixa's
compliance with Section 13.4, Nordion agrees to indemnify, defend and hold
Corixa and its Affiliates and their respective directors, officers, employees
and agents harmless from and against any damages, claims, liabilities and
expenses, including, without limitation, reasonable attorneys' fees, resulting
from any third party claims or suits ("General Claims Against Corixa") arising
out of (i) Nordion's manufacture, handling, storage, labeling, packaging or
delivery of Labeled Drug; (ii) Nordion's breach of any of its covenants,
warranties or representations hereunder; (iii) Nordion's negligent acts or
omissions or willful misconduct; (iv) any failure by Nordion to manufacture
Labeled Drug to meet the Specifications; (v) any failure of Nordion to
manufacture, handle, store, label, package, or transport Labeled Drug in
accordance with cGMP or any other applicable laws, regulations or other
requirements of any applicable governmental entity in the Territory; or (vi) any
failure of Nordion to manufacture Labeled Drug consistent with the applicable
sections of the IND or BLA, as applicable, and any corresponding licenses,
registrations, authorizations or approvals in the Territory.

                  (b)      Exceptions to Indemnification Obligations.
Notwithstanding the foregoing, Nordion will not be required to indemnify, defend
and hold Corixa or its Affiliates and their respective directors, officers,
employees and agents harmless from and against any General Claims Against Corixa
to the extent arising out of (i) Corixa's breach of any of its warranties or
representations hereunder, or (ii) Corixa's negligent acts or omissions or
willful misconduct. Notwithstanding anything in this Section 13.2, General
Claims Against Corixa shall not include IP Claims Against Corixa.

         13.3     Intellectual Property Claims.

                  (a)      Indemnification by Nordion. Subject to Corixa's
compliance with Section 13.4, Nordion agrees to indemnify, defend and hold
Corixa and its Affiliates and their respective directors, officers, employees
and agents harmless from and against any damages, claims, liabilities and
expenses (including without limitation, reasonable attorneys' fees) resulting
from any third party claims or suits arising out of any proceeding instituted by
or on behalf of a third party based upon a claim that the Process used in
manufacturing the Labeled Drug infringes a patent in the Territory or any other
proprietary rights of a third party ("IP Claims Against Corixa").
Notwithstanding the foregoing, Nordion will not be required to indemnify, defend
and hold Corixa or its Affiliates and their respective directors, officers,
employees and agents harmless from and against any IP Claims Against Corixa
arising out of the infringement of any third party intellectual property right
by the manufacturing Process to the extent developed solely by Corixa.

                  (b)      Indemnification by Corixa. Subject to Nordion's
compliance with Section 13.4, Corixa agrees to indemnify, defend and hold
Nordion and its Affiliates and their respective directors, officers, employees
and agents harmless from and against any damages, claims, liabilities and
expenses (including without limitation reasonable attorneys' fees) resulting
from any third party claims or suits (including without limitation those claims
and suits listed in Exhibit 12.1) arising out of any proceeding instituted by or
on behalf of a third party based upon a claim that the manufacture, use or sale
of

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Labeled Drug infringes a patent in the Territory or any other proprietary rights
of a third party ("IP Claims Against Nordion"). Notwithstanding the foregoing,
Corixa will not be required to indemnify, defend and hold Nordion and its
Affiliates and their respective directors, officers, employees and agents
harmless from and against any IP Claims Against Nordion arising out of the
infringement of any third party intellectual property right by any manufacturing
processes to the extent (i) developed by Nordion, either alone or with one or
more third parties, (ii) developed for Nordion by one or more third parties, or
(iii) jointly developed by Corixa and Nordion.

         13.4     Indemnification Procedures. A Party (the "Indemnitee") which
intends to claim indemnification under this Section 13 or Section 10.1(d) shall
promptly notify the other Party (the "Indemnitor") in writing of any action,
claim or other matter (a "Claim") in respect of which the Indemnitee or any of
its Affiliates, or any of their respective directors, officers, employees or
agents intend to claim such indemnification; provided, however, the failure to
provide such notice within a reasonable period of time shall not relieve the
Indemnitor of any of its obligations hereunder, except to the extent the
Indemnitor is prejudiced by such failure. The Indemnitee agrees to the complete
control of the defense of such Claim by the Indemnitor. The Indemnitee, its
Affiliates and their respective directors, officers, employees and agents shall
cooperate fully with the Indemnitor and its legal representatives at the
Indemnitor's sole cost and expense in the investigation and defense of any such
Claim.

         13.5     Right to Participate in Defense. Without limiting Section
13.4, any Indemnitee shall be entitled to participate in, but not control, the
defense of such Claims and to engage counsel of its choice for such purpose;
provided, however, that such engagement shall be at the Indemnitee's own expense
unless (a) the engagement thereof has been specifically authorized by the
Indemnitor in writing, (b) the Indemnitor has failed to assume the defense and
engage counsel in accordance with Section 13.4 (in which case the Indemnitee
shall control the defense), or (c) in the reasonable judgment of Indemnitee's
legal counsel, a material conflict of interest between the Indemnitee and the
Indemnitor exists in respect of any such Claim, provided that, in any event, the
other provisions of this Section 13 shall continue to apply to such Claim.

         13.6     Settlement. With respect to any losses relating solely to the
payment of money damages in connection with a Claim covered by this Section 13
or Section 10.1(d) and that will not result in the Indemnitee's becoming subject
to injunctive or other relief or otherwise adversely affect the business of the
Indemnitee in any manner, and as to which the Indemnitor shall have acknowledged
in writing the obligation to indemnify the Indemnitee hereunder, the Indemnitor
shall have the sole right to consent to the entry of any judgment, enter into
any settlement or otherwise dispose of such Claim, on such terms as the
Indemnitor, in its sole discretion, shall deem appropriate. With respect to all
other such Claims, where the Indemnitor has assumed the defense of such Claims
in accordance with this Section 13, the Indemnitor shall have authority to
consent to the entry of any judgment, enter into any settlement or otherwise
dispose of such Claims provided it obtains the prior written consent of the
Indemnitee (which consent shall not be unreasonably withheld or delayed). The
Indemnitor shall not be liable for any settlement or other disposition that is
reached without the prior written consent of the Indemnitor. Regardless of
whether the Indemnitor chooses to defend or prosecute any third party claim, no
Indemnitee or any of its Affiliates, or any of their respective directors,
officers, employees or agents shall admit any liability with respect to, or
settle, compromise or discharge, any such Claims without the prior written
consent of the Indemnitor.

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         13.7     Nordion Insurance. Nordion shall at all times during the term
of this Agreement maintain in full force and effect with a reputable insurance
carrier(s) the following policies of insurance:

                  (a)      Commercial General Liability. Commercial General
Liability Insurance, covering products liability, including bodily injury and
property damage to third parties. The initial limits of coverage shall be a
minimum of [*] US dollars [*] per occurrence and in the aggregate for bodily
injury/property damage (which insurance may be on a claims made or occurrence
basis). Nordion and Corixa agree to, at least on an annual basis, review the
coverage limits. Corixa shall be added as an additional insured on such general
liability policy as its interest may appear. Nordion shall upon request provide
to Corixa a certificate(s) of insurance evidencing such coverage. The policy
shall contain a cross liability clause and shall provide for severability of
interest such that breach of a policy condition by any one insured shall not
affect the rights of the other insured.

                  (b)      Property Insurance. Property Insurance covering
damage to B1 Antibody and Corixa Equipment while it remains on Nordion's
premises or in Nordion's possession and control, in amounts not less than the
replacement cost thereof, and provided further that any such proceeds shall be
used to repair or replace such damaged or destroyed assets. Such policy shall
designate Corixa as a loss payee where its interests may appear in the event of
any insured loss or damage to B1 Antibody or Corixa Equipment. Nordion shall
upon request provide to Corixa a certificate(s) of insurance evidencing such
coverage. The policy shall contain a cross liability clause and shall provide
for severability of interest such that breach of a policy condition by any one
insured shall not affect the rights of the other insured.

                  (c)      Self Insurance; Termination of Insurance.
Notwithstanding the foregoing with respect to such General Liability and/or
Property Insurance policies, [*], provided that Nordion still must provide
Corixa with a certificate regarding such insurance. In the event that any such
insurance policy held by Nordion pursuant to this section is to be terminated or
cancelled by the insurer or Nordion, Nordion shall (to the extent possible)
provide notice to Corixa at least thirty (30) days prior to such termination or
cancellation. Nothing in this section shall serve to limit in any way the
indemnification provisions set out in this Agreement.

         13.8     Corixa Insurance. Corixa shall at all times during the term of
this Agreement maintain in full force and effect with a reputable insurance
carrier(s) the following policies of insurance:

                  (a)      Commercial General Liability Insurance. Commercial
General Liability Insurance, covering products liability, including bodily
injury and property damage to third parties. The initial limits of coverage
shall be a minimum of [*] US dollars [*] per occurrence and in the aggregate for
bodily injury/property damage (which insurance may be on a claims made or
occurrence basis). Corixa and Nordion agree to, at least on an annual basis,
review the coverage limits. Nordion shall be added as an additional insured on
such general liability policy as its interest may appear. Corixa shall, upon
request, provide to Nordion a certificate(s) of insurance evidencing such
coverage. The policy shall contain a cross liability clause and shall provide
for severability of interest such that breach of a policy condition by any one
insured shall not affect the rights of the other insured.

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                  (b)      Property Insurance. Property Insurance covering
damage to B1 Antibody, while the B1 Antibody remains on Corixa's premises or in
Corixa's possession and control, in amounts not less than the replacement cost
thereof, and provided further that any such proceeds shall be used to repair or
replace such damaged or destroyed assets. The insurance policy shall designate
Corixa as a loss payee where its interests may appear in the event of any
insured loss or damage to B1 Antibody. Corixa shall upon request provide to
Nordion a certificate(s) of insurance evidencing such coverage. The policy shall
contain a cross liability clause and shall provide for severability of interest
such that breach of a policy condition by any one insured shall not affect the
rights of the other insured.

                  (c)      Self Insurance; Termination of Insurance.
Notwithstanding the foregoing with respect to such General Liability and/or
Property Insurance policies, [*], provided that Corixa still must provide
Nordion with a certificate regarding such insurance. In the event that any such
insurance policy held by Corixa pursuant to this section is to be terminated or
cancelled by the insurer or Corixa, Corixa shall, (to the extent possible)
provide notice to Nordion at least thirty (30) days prior to such termination or
cancellation. Nothing in this section shall serve to limit in any way the
indemnification provisions set out in this Agreement.

14.      Confidentiality.

         14.1     Obligations. Except as set forth below, all information
disclosed by one Party to the other Party in connection with this Agreement or
the Previous Agreements hereunder shall be deemed to be the disclosing Party's
"Confidential Information." Confidential Information shall include, but not be
limited to, information relating to the B1 Antibody and the structure of Labeled
Drug, any know-how relating to the process for the production of Labeled Drug,
and the manufacturing cost and other financial arrangements made pursuant to
this Agreement. Each Party agrees that it will take the same steps to protect
the confidentiality of the other Party's Confidential Information as it takes to
protect its own proprietary and confidential information, which shall in no
event be less than reasonable steps. Each Party and its employees and agents
shall protect and keep confidential and shall not use, publish or otherwise
disclose to any third party, except as permitted by this Agreement, or with the
other Party's written consent, the other Party's Confidential Information.
Except as provided in Section 14.2, Corixa's Confidential Information includes,
without limitation, the Corixa IP, the Specifications, the Process, and the
content of Corixa's BLA and IND applications, except to the extent it contains
Nordion Confidential Information. Except as provided in Section 14.2, Nordion's
Confidential Information includes, without limitation, the Nordion IP (including
improvements to Nordion IP), Isotope Specifications, and Background Technology
(including improvements thereto). The content of this Agreement and Quality
Policy Manual shall be deemed to be the Confidential Information of both
Parties.

         14.2     Exceptions. For the purposes of this Agreement, Confidential
Information shall not include such information that:

                  (a)      Was already known to the receiving Party at the time
of disclosure by the other Party, other than under an obligation of
confidentiality; or

                  (b)      Was generally available to the public or was
otherwise part of the public domain at the time of disclosure or became
generally available to the public or otherwise part of the public

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domain after disclosure other than through any act or omission of the receiving
Party in breach of this Agreement;

                  (c)      Was lawfully disclosed to the receiving Party, other
than under an obligation of confidentiality, by a third party who had no
obligation not to disclose such information to others; or

                  (d)      Was independently developed by or for the receiving
Party without the aid, application or use of Confidential Information, as can be
shown by the receiving Party through documentary evidence.

         14.3     Authorized Disclosure. Each Party may disclose Confidential
Information hereunder to the extent such disclosure is reasonably necessary for
prosecuting or defending against litigation, complying with applicable
government laws or regulations or conducting preclinical or Clinical Trials,
provided that if a Party is required by law or regulation to make any such
disclosure of the other Party's Confidential Information, it will, except where
impracticable for necessary disclosures (for example, in the event of medical
emergency), give reasonable advance notice to the other Party of such disclosure
requirement and will use its reasonable efforts to secure confidential treatment
of such Confidential Information required to be disclosed. In addition, upon
prior written approval of Nordion, Corixa may disclose, under a comparable
obligation of confidentiality and on a need-to-know basis, information received
under this Agreement to its other partners for the development or
commercialization of Labeled Drug. Neither Party shall disclose Confidential
Information of the other Party in any patent filings without the prior written
consent of the other Party.

         14.4     External Communications. Subject to Section 5.9 governing
communications of Complaints, Adverse Events and results of investigations
related thereto to the public and/or regulatory authorities, any other press
releases or other similar public communication by either Party relating to this
Agreement shall be approved in advance by the other Party, which approval shall
not be unreasonably withheld or delayed. Those press releases or other similar
public communications required by applicable laws, regulations, rules or orders
may be provided without advance written consent of the other party, provided (i)
the communication is provided to such Party as soon as practicable after the
release or communication thereof, and (ii) any such disclosure does not contain
the Confidential Information of such Party. If such communication contains
Confidential Information of a Party, such Party shall be entitled to receive the
communication in advance of its release and, to the extent permitted by law,
purge the communication of its Confidential Information. Any disclosures of
information for which consent has previously been obtained (and information of a
similar nature to that which has been previously disclosed publicly with respect
to this Agreement), shall not require advance approval.

         14.5     Survival. All obligations of confidentiality and non-use
imposed upon the Parties under this Agreement shall expire ten (10) years after
the expiration or termination of this Agreement.

15.      Governing Law; Dispute Resolution.

         15.1     Governing Law. This Agreement will be governed by, construed
and enforced in accordance with the laws of the State of New York without regard
to principles of conflicts of law, as applied to contracts executed and
performed in New York by New York residents. The application of the United
Nations Convention for the International Sale of Goods is expressly excluded.

                                      -33-

<PAGE>

         15.2     Consent to Jurisdiction. Each of the Parties hereby submits to
the nonexclusive jurisdiction of the United States federal and state courts
located in the City, State and County of New York solely in respect of the
interpretation and enforcement of the provisions of this Agreement, and hereby
waives, and agrees not to assert, as a defense in any action, suit or proceeding
for the interpretation or enforcement of this Agreement, that it is not subject
thereto or that such action, suit or proceeding may not be brought or is not
maintainable in such courts or that this Agreement may not be enforced in or by
such courts or that its property is exempt or immune from jurisdiction execution
or enforcement, that the suit, action or proceeding is brought in an
inconvenient forum, or that the venue of the suit, action or proceeding is
improper.

         15.3     Dispute Resolution.

                  (a)      Good Faith Negotiations. If the Parties fail to
resolve any claim, dispute, or controversy ("Dispute") of whatever nature
arising out of or relating to this Agreement (other than one relating to the
validity, enforceability, infringement or misappropriation of intellectual
property rights, which shall not be subject to this Section 15.3(a)), or
concerning the interpretation, effect, termination, validity, performance,
and/or breach of this Agreement, either Party may refer the Dispute, to such
officers as the Parties may designate in writing from time to time, for
attempted resolution by good faith negotiations within thirty (30) days after
such notice is received. If such Dispute is not solved by the end of such thirty
(30) day period, the Parties shall be free to pursue any legal or equitable
remedy available to them. Each Party will bear its own attorneys' fees and other
costs and expenses.

                  (b)      Intellectual Property. Notwithstanding anything to
the contrary, any disputes regarding the validity, scope, enforceability,
infringement or misappropriation of patents, copyright, trade secrets or
trademarks shall be submitted to a court of competent jurisdiction in the
territory in which such rights apply.

16.      General Provisions.

         16.1     Independent Contractors. Corixa and Nordion shall be
independent contractors and shall not be deemed to be partners, joint venturers
or each other's agents, and neither Party shall have the right to act on behalf
of the other, except as is expressly set forth in this Agreement.

         16.2     Disclaimer of Consequential Damages. Except for damages
arising out of a breach of Section 10 (Intellectual Property) or 14
(Confidentiality), in no event shall either Party be liable to the other Party
or its Affiliates for indirect, contingent, incidental, special or consequential
damages, including without limitation, any claim for damages based on lost
profits, cost of capital, loss of business opportunity or loss of time.

         16.3     Entire Agreement; Amendment.

                  (a)      Entire Agreement. This Agreement, which includes the
attached Exhibits, contains the sole and entire understanding of the Parties
related to its subject matter and supersedes all prior or contemporaneous oral
or written agreements concerning the subject matter as of the Effective Date.

                  (b)      Amendment. This Agreement cannot be changed orally
and no modification of this Agreement will be recognized or have any effect,
unless the writing in which it is set forth is

                                      -34-

<PAGE>

signed by authorized representatives of Nordion and Corixa, nor will any waiver
of any of the provisions of this Agreement be effective unless in writing and
signed by the Party to be charged therewith.

                  (c)      Survival Under Previous Agreements. The Parties agree
that the Previous Agreements are hereby terminated and of no further force and
effect. Notwithstanding the forgoing, Sections 8, 9, 14 and 21 of the
Development Agreement, Sections 2.6(c), 5.3, 5.4, 11.2, 11.3, 11.5, 11.6 and
Article 7 of the Facilities Agreement and Sections 8.6, 9.3, 10.3, 10.4, 16.2,
16.4, 16.6 and Article 12 (except Sections 12.5 and 12.6) of the Previous Supply
Agreement, shall survive in accordance with their terms.

         16.4     No Conflicts. To the extent that the terms of the Iodine
Supply Agreement or the Quality Policy Manual are inconsistent with the terms of
this Agreement, the terms of this Agreement shall govern.

         16.5     Assignment. This Agreement shall inure to the benefit of, and
be binding upon, the respective successors and assigns of the Parties. Without
the written consent of the other Party hereto, which shall not be unreasonably
withheld, neither Party shall sell, transfer, assign, pledge or otherwise
dispose of, whether voluntarily, involuntarily, by operation of law or
otherwise, this Agreement or any of its rights or duties hereunder; provided,
however, that either party may assign or transfer this Agreement or any of its
rights or obligations hereunder without the consent of the other Party (a) to
any Affiliate of such Party, subject to the assigning Party remaining jointly
and severally liable under this Agreement with such Affiliate assignee or (b) to
any third party with which it merges or consolidates, or to which it transfers
all or substantially all of its assets to which this Agreement relates; provided
further that in any such event ((a) or (b)) such Affiliate assignee, third party
assignee or surviving entity assumes in writing all of the assigning Party's
obligations under this Agreement. Any purported assignment or transfer in
violation of this Section shall be void ab initio and of no force or effect.

         16.6     Waiver. Failure or delay by either Party to enforce at any
time any of the provisions of this Agreement shall not be construed as a waiver
of its rights hereunder. Any waiver of a breach of any provision hereof shall
not affect either Party's rights in the event of any additional breach.

         16.7     Notice. All notices under this Agreement must be made in
writing and mailed or delivered to the following:

         Corixa:           Corixa Corporation
                           1124 Columbia Street, Suite 200
                           Seattle, WA 98104 U.S.A.
                           Attn: Chief Executive Officer
                           Copy: General Counsel

                                      -35-

<PAGE>

         Nordion:.         MDS Nordion.
                           447 March Road
                           Ottawa, Ontario K2K 1X8 CANADA
                           Attn: Senior Vice President, Nuclear Medicine
                           Copy: General Counsel

         16.8     Force Majeure. If the performance of any part of this
Agreement by either Party, or of any obligation under this Agreement, including,
without limitation, Section 6, is prevented, restricted, interfered with or
delayed by reason of an event of Force Majeure, the Party so affected shall,
upon giving written notice to the other Party, be excused from such performance
to the extent and for the duration of such prevention, restriction, interference
or delay; provided, however, that the affected Party shall use commercially
reasonable efforts to avoid or remove such event of Force Majeure and shall
continue performance with the utmost dispatch whenever such causes are removed.
In the event a Force Majeure prevents either Party from carrying out its
obligations for a period in excess of sixty (60) days, then the other Party may
terminate this Agreement upon thirty (30) days prior written notice; provided,
however, that any such termination by Corixa shall not be deemed a termination
under Section 11.3. Without limiting the generality of the foregoing and for the
avoidance of doubt, a Force Majeure event affecting Nordion shall result in a
reduction of the applicable minimum purchase commitment provided for in Section
3.1(g).

         16.9     Definition of Force Majeure. "Force Majeure" shall mean an
event beyond the reasonable control of a Party which prevents, delays or
interferes with the performance by such Party of any of its obligations
hereunder, if such event occurs by reason of: an act of God; flood; fire;
explosion; casualty or accident; war; revolution; civil commotion; acts of
public enemies; blockade or embargo; terrorist act; or any law, order or
proclamation of any government; failure of suppliers to provide materials,
services, equipment or machinery; interruption of or delay in transportation;
strike or labor disruption; or any other cause, whether similar or dissimilar to
those above enumerated.

         16.10    No Subcontracting.

                  (a)      Prohibition. Under no circumstances will Nordion
subcontract out to a third party all or any part of the development,
manufacturing or testing of (i) Labeled Drug, or (ii) the B1 Antibody without
the prior written consent of Corixa.

                  (b)      Exceptions. Except as set forth in subsection (a),
Nordion may subcontract out to a third party the development, manufacturing or
testing of any materials used in the manufacture of Labeled Drug, provided that
(i) Nordion provides Corixa with prior written notice of such subcontracting
arrangement and any subsequent changes thereto, (ii) Corixa may audit Nordion's
subcontractor qualification criteria and review Nordion's subcontractor audits,
and (iii) Corixa may direct a replacement of such subcontractor in its
reasonable discretion and reimburse Nordion for all incremental costs associated
with such replacement, unless such direction from Corixa is due to a failure to
perform by such subcontractor.

         16.11    Headings. The headings herein are for the purpose of
convenience of reference only and are not intended to define or limit the
contents of this Agreement.

                                      -36-

<PAGE>

         16.12    Remedies. All remedies contained herein shall be cumulative
and in addition to any other rights or remedies that may be available to such
Party.

         16.13    Time is of the Essence. Any reference to a specific number of
days or to the "delivery" or "Release" of any item or to any action which is
required to be taken hereunder shall be interpreted in the context that time is
of the essence in this Agreement.

         16.14    Cooperation. Each of he Parties shall, and shall cause their
respective Affiliates, if applicable, to cooperate with the other with respect
to the filing and maintenance of any and all regulatory approvals relating to
Labeled Drug required by any relevant governmental agency or entity. Upon
reasonable request of a Party, such cooperation shall include access during
normal business hours afforded to the records and information that are
reasonably relevant to such approvals, and making employees and agents available
on a mutually convenient basis to provide additional information and explanation
of any material provided hereunder, and the Party seeking regulatory approval
shall reimburse the other Party for all its reasonable out-of-pocket expenses in
connection therewith.

         16.15    Advice of Legal Counsel. Each Party acknowledges and
represents that, in executing this Agreement, it has had the opportunity to seek
advice as to its legal rights from legal counsel and that the person signing on
its behalf has read and understood all of the terms and provisions of this
Agreement. This Agreement shall not be construed against either Party by reason
of the drafting or preparation thereof.

         16.16    Severability. In the event that any one or more of the
provisions contained in this Agreement should be held invalid, illegal or
unenforceable in any respect, the validity, legality and enforceability of the
remaining provisions contained herein shall not in any way be affected or
impaired thereby. The Parties agree to replace any invalid provision or parts
thereof by new provision(s) which closely approximate the economic and
proprietary results intended by the Parties.

         16.17    Currency. All amounts set out in this Agreement shall be in
United States dollars.

         16.18    Compliance. This Agreement shall be carried out in compliance
with all applicable laws, rules, regulations and orders of federal, state,
provincial, territorial or local governments and in compliance with the
applicable by-laws and/or articles of the Parties.

                  [Remainder of Page Intentionally Left Blank]

                                      -37-

<PAGE>

         16.18    Counterparts. This Agreement may be signed in counterparts,
each of which shall be deemed an original and all of which shall together
constitute one document.

         IN WITNESS WHEREOF, the Parties have caused this Agreement to be
executed by their respective duly authorized officers as of the date first
written above.

MDS (CANADA) INC., through its division,      CORIXA CORPORATION
MDS NORDION

By:    /s/ Iain Trevena                              By:  /s/ Michelle Burris
   ------------------------------                       ------------------------
Name:  Iain Trevena                           Name:  Michelle Burris
Title: Senior Vice President,                 Title: Senior Vice President and
       Nuclear Medicine                              Chief Financial Officer

                                              COULTER PHARMACEUTICAL, INC.

                                              By:    /s/ Michelle Burris
                                                 -------------------------------
                                              Name:  Michelle Burris
                                              Title: Chief Financial Officer

                                      -38-

<PAGE>

                                   Exhibit 1.6
                           B1 Antibody Specifications

<TABLE>
<CAPTION>
Attribute        Test Method        Specification
<S>              <C>                <C>
   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]
</TABLE>

-----------------------------------
* Confidential treatment requested.

<PAGE>

B1 Antibody Specifications (cont's) End of Shelf-Life Specifications:

<TABLE>
<CAPTION>
Attribute        Test Method        Specification
<S>              <C>                <C>
   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]

   [*]               [*]                 [*]
</TABLE>

* Performed at Packaged Bulk expiry

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                  Exhibit 1.16
                        CD-20 Antigen Cells Specification

<TABLE>
<CAPTION>
=================================================
Attribute        Test Method        Specification
=================================================
<S>              <C>                <C>
   [*]               [*]                 [*]
=================================================
</TABLE>

B-1 Antibody End of Shelf-Life Specifications

<TABLE>
<CAPTION>
=================================================
Attribute        Test Method        Specification
=================================================
<S>              <C>                <C>
   [*]               [*]                 [*]
=================================================
</TABLE>

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                  Exhibit 1.28
                                Corixa Equipment

<TABLE>
<CAPTION>
PURCH     YR IN                       MDSN
 YEAR      SRV      PO#     PS#     INVOICE #     VENDOR     DESCRIPTION     FACILITY     COMMENTS
-----     -----     ---     ---     ---------     ------     -----------     --------     --------
<S>       <C>       <C>     <C>     <C>           <C>        <C>             <C>          <C>
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
[*]       [*]       [*]     [*]     [*]           [*]        [*]             [*]          [*]
</TABLE>

-----------------------------------
* Confidential treatment requested.
<PAGE>

                                 Exhibit 1.61(a)
                [*] ISOTOPE SPECIFICATIONS (SODIUM IODIDE I-131)

<TABLE>
<CAPTION>
--------------------------------
Characteristic
--------------------------------
<S>                          <C>
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
</TABLE>

     [*]

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                 Exhibit 1.61(b)
                [*] Isotope Specifications (Sodium Iodide I-131)

<TABLE>
<CAPTION>
--------------------------------
Characteristic
--------------------------------
<S>                          <C>
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
      [*]                    [*]
--------------------------------
</TABLE>

     [*]

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                  Exhibit 1.86
                                 Specifications

================================================================================
                Labeled Drug Dosimetric Dosage Form (960702.SPE)
================================================================================

     [*]

-----------------------------------
* Confidential treatment requested.

<PAGE>

================================================================================
                Labeled Drug Therapeutic Dosage Form (960703.SPE)
================================================================================

     [*]

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                   Exhibit 3.1
                       Forecasts and Firm Order Schematic

<TABLE>
<CAPTION>
-------------------------------------------------------------------------------------------
        [*]                             [*]                                    [*]
-------------------------------------------------------------------------------------------
                              [*]                 [*]                [*]                [*]
-------------------------------------------------------------------------------------------
<S>                           <C>                 <C>                <C>                <C>
[*]                           [*]
-------------------------------------------------------------------------------------------
[*]                           [*]                                                       [*]
-------------------------------------------------------------------------------------------
[*]                           [*]                 [*]                [*]                [*]
-------------------------------------------------------------------------------------------
[*]                           [*]                 [*]                [*]                [*]
-------------------------------------------------------------------------------------------
[*]                           [*]                 [*]                [*]                [*]
-------------------------------------------------------------------------------------------
[*]                           [*]                 [*]                [*]                [*]
-------------------------------------------------------------------------------------------
[*]                           [*]                 [*]                [*]                [*]
-------------------------------------------------------------------------------------------
[*]                           [*]                 [*]                [*]                [*]
-------------------------------------------------------------------------------------------
[*]                           [*]                 [*]                [*]                [*]
-------------------------------------------------------------------------------------------
[*]                                               [*]                [*]                [*]
-------------------------------------------------------------------------------------------
[*]                                               [*]                [*]                [*]
-------------------------------------------------------------------------------------------
</TABLE>

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                   Exhibit 5.3

                              QUALITY POLICY MANUAL

                                      [[*]]

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                 Exhibit 5.12(b)

                            CONFIDENTIALITY AGREEMENT
                      (Corixa, Affiliates, Representatives)

TO:      MDS Nordion, a division of MDS (Canada) Inc.
         447 March Road
         Ottawa, ON K2K 1X8
         Canada

         ("Nordion")

WHEREAS:

(i)      Corixa Corporation and Coulter Pharmaceutical, Inc., (collectively
         referred to as "Corixa") and Nordion, have entered into a Bexxar Supply
         Agreement dated as of the ____ day of ____ 2003 (the "Agreement"),

(ii)     Pursuant to and in accordance with the terms and conditions of section
         5.12 (b) of the Agreement Corixa, its Affiliates and representatives as
         mutually agreed, shall have access to Nordion's I-131 labeled B-1
         Antibody ("Labeled Drug") manufacturing facility (the "Facility") and
         related Labeled Drug procedures, and

(iii)    Pursuant to the Agreement it has been agreed that access to the
         Facility by such persons shall only be permitted by Nordion subject to
         execution of a confidentiality agreement.

NOW, THEREFORE, in consideration of Nordion permitting ___________________,
("Recipient") having place of business at ____________, access to the Facility,
Recipient agrees and undertakes as follows:

1.       Preservation of Confidential Information

         Recipient agrees to preserve as confidential all Confidential
         Information which it may obtain while having access to Nordion's plant,
         the Facility and/or to Nordion's Labeled Drug procedures.

2.       Permissible Disclosure

         The Confidential Information shall only be used for the purpose of
         observation of the Process (as defined in the Agreement), and/or audit
         for determination of compliance of the Facility to specifications,
         cGMPs and other regulatory requirements as related to Labeled Drug and
         not for any other use or purpose, commercial or otherwise (the
         "Purpose"). Recipient shall not without the prior written consent of
         Nordion, disclose any of the Confidential Information to any third
         party, save to Recipient's directors, officers, or employees who have a
         need to know such information to accomplish the Purpose and who shall
         be informed of the confidential nature of the information and who shall
         be bound by a similar obligation of confidentiality.

<PAGE>

3.       Return of Confidential Information

         All right title and interest in and to the Confidential Information
         shall be retained by Nordion. All Confidential Information including
         copies, summaries and notes related thereto, shall be promptly
         surrendered to Nordion upon expiration or termination of this agreement
         or such earlier date as requested by Nordion in writing.

4.       Limitations of Confidentiality

         "Confidential Information" means all information, whether disclosed
         orally, in writing, via other media or tangible form, or obtained by
         observation or inspection, concerning the functionality and operations
         of Nordion's plant, Facility layout, Nordion's data, trade secrets,
         patents, software, processes, methods, know how, technical information,
         designs, drawings, formulas, concepts, reports, product development
         activities, material samples, business plans, forecasts, marketing
         plans, customer and supplier lists, business strategies and financial
         information, and such other information as by its nature or designation
         is confidential or proprietary information.

         Notwithstanding the foregoing "Confidential Information" shall not
         include information which:

         (a)      at the time of disclosure to the Recipient is or thereafter
                  becomes part of the public domain through no act or omission
                  of Recipient or its employees, agents or representatives,

         (b)      at the time of disclosure to the Recipient has been or
                  thereafter is lawfully disclosed to Recipient by a person
                  under no obligation of confidentiality to Nordion with respect
                  to such information,

         (c)      is independently developed as shown by written records, by an
                  agent or employee of the Recipient having no knowledge of or
                  access to any Confidential Information disclosed hereunder,

         (d)      is required to be disclosed due to judicial process or
                  authority, provided that Recipient shall provide Nordion
                  prompt written notice thereof in order to permit Nordion to
                  seek a protective order,

         (e)      was known to Recipient, without restriction, at the time of
                  disclosure, as demonstrated by files in existence at the time
                  of disclosure,

         (f)      is disclosed with the prior written approval of Nordion, or

         (g)      is disclosed generally to third parties by Nordion without
                  restrictions similar to those contained in this Agreement.

         The Recipient shall have the burden of demonstrating that information
         which would otherwise constitute Confidential Information is within the
         scope of the above exceptions to confidentiality.

5.       Term

         Recipient shall maintain the Confidential Information in confidence for
         a period of ten (10) years from the date of signature set out below.
         This agreement may be terminated by either party at any time upon
         written notice to the other party. Termination of this agreement shall
         not affect

<PAGE>

         Recipient's continuing obligations hereunder, with respect to
         Confidential Information received up to the date of termination.

6.       Injunctive Relief

         Recipient acknowledges that the Confidential Information constitutes
         and contains confidential and proprietary information of a special and
         unique nature and value. Recipient also acknowledges that Nordion may
         suffer irreparable harm in the event of breach of Recipient's
         obligations and that monetary damages may be inadequate to compensate
         Nordion for such breach. Recipient accordingly agrees that in the event
         of a breach or threatened breach of its obligations under this
         Agreement, Nordion shall in addition to any other remedies available,
         be entitled to seek injunctive relief.

7.       No License

         The disclosure of Confidential Information to Recipient shall not be
         construed as granting Recipient any right or license with respect to
         the Confidential Information.

8.       Severability

         This agreement contains the entire agreement with respect to its
         subject matter and no modification or waiver shall be binding unless
         set out in writing. If any provision of this agreement is held to be
         invalid, illegal, or unenforceable, such invalidity, illegality or
         unenforceability shall not affect any other portion of this agreement
         and there shall be deemed substituted therefor such provision as will
         most fully realize the intent of the parties expressed in this
         agreement to the fullest extent permitted by applicable law.

9.       Assignment

         This agreement shall not be assigned by Recipient in whole or in part
         without the prior written consent of Nordion and shall be binding upon
         the parties, their respective successors and permitted assigns.

10.      Applicable Law

         This Agreement will be governed by, construed and enforced in
         accordance with the laws of the the Province of Ontario, Canada without
         regard to principles of conflicts of law.

<PAGE>

IN WITNESS whereof the Recipient has executed this Agreement as of the _____ day
of _____.

(RECIPIENT)

By: ___________________________

<PAGE>

                                 Exhibit 5.12(c)

[*]

-----------------------------------
* Confidential treatment requested.

<PAGE>

                              Exhibit 5.12 (c)(vi)

[*]

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                    Exhibit 7

                               STATEMENTS OF WORK

[*]

-----------------------------------
* Confidential treatment requested.

<PAGE>

                         EXHIBIT 9.1 BATCH PRICING ($US)

[*]

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------
                           [*]                                 [*]                                 [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
                  [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
<S>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
</TABLE>

[*]

<TABLE>
<CAPTION>
------------------------------------------------------------------------------------------------------------------------
                           [*]                                     [*]                                  [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
                  [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
<S>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>      <C>
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
[*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]      [*]
------------------------------------------------------------------------------------------------------------------------
                                                                                                                     [*]
------------------------------------------------------------------------------------------------------------------------
</TABLE>

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                  Exhibit 12.1
                          Schedule of Claims and Suits

1. On September 10, 2001, IDEC Pharmaceuticals ("IDEC") filed a complaint
against Corixa and the University of Michigan in the US District Court for the
Southern District of California, case docket #01CV1637IEG (RBB), seeking to
invalidate seven of Corixa's US patents (US Patent Nos. 5,595,721, 5,843,398,
6,015,542, 6,022,521, 6,090,365, 6,251,362, and 6,287,537) that claim
compositions of matter comprising Bexxar(R) and methods of treating B-cell
non-Hodgkin's lymphoma with same therapy. (There are no foreign counterparts to
these patents.) On September 11, 2001, Corixa and the University of Michigan
filed a counterclaim against IDEC in the US District Court for the District of
Delaware, asserting that IDEC's marketing of its product, Zevalin(R) (a murine,
radiolabeled, anti-CD20 antibody), infringes four of the seven Corixa US
patents-in-suit in the suit that IDEC filed (US Patent Nos. 5,595,721,
6,015,542, 6,090,365, and 6,287,537). On July 16, 2002, following an order
transferring the second case to the US District Court for the Southern District
of California, these two actions were consolidated and are still pending in the
US District Court for the Southern District of California.

2. On June 2, 2003, IDEC moved to amend its complaint to add a claim for
declaratory judgment relief of non-infringement and invalidity of our US Patent
No. 6,565,827. Issued Patent No. 6,565,827 covers composition of matter used in
the treatment of B-cell non-Hodgkin's lymphoma. Also on June 2, 2003, IDEC filed
a separate lawsuit in the US District Court for the Southern District of
California, seeking declaratory judgment of non-infringement and invalidity of
issued Patent No. 6,565,827.

3. On February 25, 2003, IDEC filed a complaint against Corixa and
GlaxoSmithKline, case docket #03CV00380J, for patent infringement of the US
Reissue patent, US RE38,008, which claims methods of enhancing the delivery of
conjugated antibodies to solid tumor target cells. (There are equivalent patents
to US RE 38,008 that have issued in Canada and in the European Union, but IDEC
has not filed suit against Corixa or GlaxoSmithKline on either of these
patents).

-----------------------------------
* Confidential treatment requested.

<PAGE>

                                 Exhibit 12.2(c)
                           Returned or Destroyed Items

<TABLE>
<CAPTION>
Purch      Yr In                          MDSN
Year        Srv       PO#      PS#      Invoice #          Vendor             Description                 Facility         Comments
-----      -----      ---      ---      ---------          ------             -----------                 --------         --------

<S>        <C>        <C>      <C>      <C>                <C>                <C>                         <C>              <C>

[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]
[*]        [*]         [*]     [*]        [*]               [*]                 [*]                          [*]             [*]

</TABLE>

---------------
*Confidential treatment requested.

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00053-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00053-of-00352.parquet"}]]