PURCHASE AGREEMENT AND ESCROW INSTRUCTIONS

THIS PURCHASE AGREEMENT AND ESCROW INSTRUCTIONS ("Agreement") is made as of August 31, 2000 (the "Effective Date"), by and between IVEY RANCH DEVELOPMENT COMPANY, LLC, a California limited liability company ("Seller"), and IDEC PHARMACEUTICALS CORPORATION, a Delaware corporation ("Buyer"), as follows:

1. PURCHASE AND SALE. Upon all the terms and conditions contained herein, Buyer hereby agrees to purchase from Seller and Seller agrees to acquire from the existing fee owner, Ivey Ranch, Inc. (the "Fee Owner"), or to cause the Fee Owner to convey directly to Buyer, and to sell to Buyer that certain real property (the "Land") (a) located within the area commonly referred to as Ocean Ranch in the City of Oceanside, California, (b) consisting of approximately sixty and 4/10 (60.4) acres of net usable land and (c) depicted on Exhibit A attached hereto and incorporated herein by this reference. The Land is identified as Parcel 4 of proposed Lot Line Adjustment No. PLA-10-2000 (the "Lot Line Adjustment"). Buyer acknowledges that the Lot Line Adjustment will need to be recorded in the Official Records of San Diego County, California to cause the Land to be one or more separate legal parcels pursuant to the California Subdivision Map Act, all as contemplated by Section 7 (d) below. Buyer shall have the right to approve the recorded Lot Line Adjustment, but approval shall not be unreasonably withheld if it is insubstantial conformance with the depiction on Exhibit A.

2. OPENING OF ESCROW. Within two (2) business days of the execution of this Agreement, Seller and Buyer shall open an escrow (the "Escrow") with First American Title Insurance Company at Two First American Way, Santa Ana, California 92707 (the "Escrow Holder") by delivering a fully executed copy of this Agreement to Escrow Holder. Escrow Holder will execute copies of this Agreement and return fully executed copies hereof to Buyer and Seller when Escrow has opened. Escrow shall be deemed open upon Escrow Holder's execution hereof. In addition, the parties agree to be bound by the standard escrow General Provisions attached hereto as Exhibit B and incorporated herein by this reference. In the event of any inconsistency between this Agreement and such General Provisions, the provisions of this Agreement shall prevail.

3. CLOSING OF ESCROW. The closing (the "Closing") of the purchase and sale of the Land shall take place through Escrow three (3) business days after recordation of the Lot Line Adjustment, but in no event later than September 1, 2000 (the "Closing Date").

4. PURCHASE PRICE. The purchase price for the Land (the "Purchase Price") shall be Eighteen Million Four Hundred Seventeen Thousand One Hundred Sixty-Eight Dollars ($18,417,168). The Purchase Price shall be payable as follows:

(a) INITIAL DEPOSIT. Concurrently with the opening of Escrow, Buyer shall deposit into Escrow cash in the amount of Two Hundred Thousand Dollars ($200,000).

(b) ADDITIONAL DEPOSIT. On or before the expiration of the Due Diligence Period (as defined in Section 7 below), Buyer shall deposit into Escrow additional cash in the amount of One Hundred Fifty Thousand Dollars ($150,000). Escrow Holder shall invest the initial and additional deposits (collectively, the "Deposit"), upon receipt, in an interest-bearing account approved by Buyer, and, except as set forth in Section 11 (b) below, all interest thereon shall be credited to Buyer. Buyers hall pay all costs and assume all risks in connection with the investment of the Deposit.

(c) CASH AT CLOSING. The remainder of the Purchase Price (after credit for the deposits made pursuant to Sections 4 (a) and (b)) shall be deposited into Escrow, in cash or by federal wire transfer of immediately available funds, by Buyer at or prior to Closing.

5. COSTS AND PRORATIONS.

(a) ESCROW AND TITLE FEES. Buyer and Seller shall each pay one-half (1/2) of the Escrow fees. Seller shall bear the cost of (i) all documentary transfer taxes, (ii) the premium which would be required for an ALTA Standard Coverage Owner's Policy of Title Insurance With Regional Exceptions if issued by the Title Company (as defined below) insuring Buyer's title to the Land in the amount of the Purchase Price, including a mechanics' lien endorsement as described in Section 8 (c) below and (iii) the cost of recording the Grant Deed (as defined below). Buyer shall bear the cost of any increased premium attributable to other endorsements and the delivery of an extended coverage, ALTA Owner's Policy of Title Insurance. All other costs or expenses not otherwise provided for in this Agreement shall be apportioned oral located between Buyer and Seller in the manner customary in San Diego County, California.

(b) TAXES AND ASSESSMENTS. All current real property taxes and all payments on general and special bonds and assessments on the Land shall be prorated through Escrow between Buyer and Seller as of Closing based upon the latest available tax information, using the customary escrow procedures. Any taxes levied under the Supplemental Tax Roll and attributable to the period prior to Closing shall be paid by Seller, and any such taxes attributable to the period from and after Closing shall be paid by Buyer. If the Land is part of a larger tax parcel which remains unsegregated on the San Diego, California Tax Assessors' Rolls for the coming fiscal tax year and any installment of tax becomes due before such segregation is made, then, prior to the later of (i) thirty (30) days after notice from Seller, or (ii) two (2) business days prior to the date such taxes become due and payable, Buyers hall pay Seller for the percentage of taxes and assessments as regards the Land on an acreage basis which is equal to the percentage obtained by dividing the acreage of the Land by the acreage for the entire tax parcel. Notwithstanding the foregoing, Buyer shall be fully and solely responsible for the payment of all taxes levied under the Supplemental Tax Roll relating to the Land, and if Seller pays for any such taxes, Buyer shall reimburse Seller for such amounts upon thirty (30) days notice from Seller. Additionally, if any portion of such tax parcel is reassessed due to improvements constructed thereon, the owner of the portion of such tax parcel upon which such improvements are constructed shall be fully and solely responsible for such increased assessment, and if Seller pays for any such taxes which are Buyer's responsibility, Buyer shall reimburse Seller for such amounts upon thirty (30) days notice from Seller. If the Land is not separately assessed and segregated at Closing, Buyer and Seller agree to cause the Land thereafter to be separately assessed and segregated in Buyer's name on the current tax roll as provided by applicable statutes.

6. HOLDBACK ACCOUNT.

(a) HOLDBACK AMOUNT. At Closing, ninety percent (90%) of the Purchase Price (the "Holdback Amount") shall not be disbursed by Escrow Holder to Seller, but shall be held in Escrow and disbursed as provided herein. The remainder of the Purchase Price shall be disbursed to Seller at Closing, after payment of Seller's share of Closing costs as provided herein. Of the Holdback Amount, an amount equal to One Million Three Hundred Fifteen Thousand Five Hundred Twelve Dollars ($1,315,512) shall be set aside to be utilized as set forth in Section 6 (b) below (the "Government Funds and Other Savings Account"). The excess of the Holdback Amount over the Government Funds and Other Savings Account shall be set aside to be utilized as set forth in Section 6 (c) below (the "Improvements Account"). Both the Government Funds and Other Savings Account and the Improvements Account shall be invested by Escrow Holder in separate FDIC-insured money-market accounts, which accounts may be withdrawn immediately upon demand and do not carry any early withdrawal penalties or other monetary penalties or charges. Any interest earned with respect to the Government Funds and Other Savings Account or the Improvements Account shall be for the benefit of Buyer.

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