EXHIBIT 10.20 THIS SECURITY AND THE COMMON STOCK ISSUABLE UPON ITS CONVERSION HAVE NOT BEEN REGISTERED UNDER THE U.S. SECURITIES ACT OF 1933, AS AMENDED (THE "SECURITIES ACT"), AND MAY NOT BE OFFERED, SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT PURSUANT TO AN AVAILABLE EXEMPTION FROM REGISTRATION UNDER THE SECURITIES ACT AND IN ACCORDANCE WITH ALL APPLICABLE SECURITIES LAWS OF THE STATES OF THE UNITED STATES AND OTHER JURISDICTIONS. CELGENE CORPORATION 9.25 % CONVERTIBLE NOTE DUE SEPTEMBER 16, 2003 No. R-1 $8,750,000 CELGENE CORPORATION, a corporation duly organized and existing under the laws of Delaware (the "Company") for value received, hereby promises to pay to Warburg Dillon Read LLC, or registered assigns, the principal sum of eight million, seven hundred and fifty thousand Dollars ($8,750,000) on September 16, 2003 and to pay interest thereon, from September 16, 1998, or from the most recent interest payment date to which interest has been paid or duly provided for, semiannually on March 16 and September 16 in each year, commencing March 16, 1999, at the rate of 9.25% per annum, until the principal hereof is due, and at the rate of 9.25% per annum on any overdue principal and premium, if any, and, to the extent permitted by law, on any overdue interest. The interest so payable, and punctually paid or duly provided for, on any interest payment date will be paid to the person in whose name this Security (or one or more predecessor Securities) is registered at the close of business on the regular record date for such interest, which shall be the March 1 or September 1 (whether or not a business day), as the case may be, next preceding such interest payment date. Payment of the principal of (and premium, if any, on) this Security shall be made upon the surrender of this Security to the Company, at its office at 7 Powder Horn Drive, Warren, NJ 07059 (or such other office within the United States as shall be notified by the Company to the holder hereof) (the "Designated Office"), in such coin or currency of the United States of America as at the time of payment shall be legal tender for the payment of public and private debts, by transfer to a U.S. dollar account maintained by the payee with a bank in the United States of America. Payment of interest on this Security shall be made by wire transfer to a U.S. dollar account maintained by the payee with a bank in the United States of America, provided that if the holder shall not have furnished wire instructions in writing to the Company no later than the record date relating to an interest payment date, such payment may be made by U.S. dollar check mailed to the address of the person entitled thereto as such address shall appear in the Company security register. In respect of any interest payment date, the Company may, at its election but subject to fulfillment of the conditions set forth in Section 6 and subject to the limitations set forth therein, pay all or a portion of the interest on this Security in shares of Common Stock having a fair market value equal to the amount then payable hereunder, as described in Section 6. 1. Redemption. This Security is subject to redemption upon not less than 30 nor more than 60 days' notice by mail, at any time on or after September 16, 2000, as a whole or in part, (in any amount that is an integral multiple of $1000) at the election of the Company, at a redemption price of 103% the principal amount thereof, together with accrued interest to the redemption date, but interest installments whose stated maturity is on or prior to such redemption date will be payable to the holder of this Security, or one or more predecessor Securities, of record at the close of business on the relevant record dates referred to on the face hereof; provided, however, that the Company may not redeem this Security on or prior to September 16, 2001 unless the Closing Price of the Common Stock exceeds 225% of the Conversion Price for each Trading Day in a period of 20 Consecutive Trading Days commencing not earlier than September 16, 2000. The term "Conversion Price" on any day shall equal $1,000 divided by the Conversion Rate in effect on each such day. 2. Conversion. (a) The holder of this Security is entitled at any time on or after September 16, 1999 and before the close of business on September 16, 2003 (or, in case this Security or a portion hereof is called for redemption or the holder hereof has exercised his right to require the Company to repurchase this Security or a portion hereof, then in respect of this Security or such portion hereof, as the case may be, until and including, but (unless the Company defaults in making the payment due upon redemption or repurchase, as the case may be) not after, the close of business on the redemption date or the Repurchase Date, as the case may be) to convert this Security (or any portion of the principal amount hereof that is an integral multiple of $1,000), into fully paid and nonassessable 1,000 shares (calculated as to each conversion to the nearest 1/100 of a share) of Common Stock of the Company at the rate of 90.91 shares of Common Stock for each $1,000 principal amount of Security (or at the current adjusted rate if an adjustment has been made as provided below) (the "Conversion Rate") by surrender of this Security, duly endorsed or assigned to the Company or in blank to the Company at the Designated Office, accompanied by written notice to the Company that the holder hereof elects to convert this Security (or if less than the entire principal amount hereof is to be converted, specifying the portion hereof to be converted). Upon surrender of this Security for conversion, the holder will be entitled to receive the interest accruing on the principal amount of this Security then being converted from the interest payment date next preceding the date of such conversion to such date of conversion. No payment or adjustment is to be made on conversion for dividends on the Common Stock issued on conversion hereof. No fractions of shares or scrip representing fractions of shares will be issued on conversion, but instead of any fractional interest, the Company shall pay a cash adjustment, computed on the basis of the Closing Price of the Common Stock on the date of conversion, or, at its option, the Company shall round up to the next higher whole share. Notwithstanding the foregoing, at no time will the holder be entitled to convert this Security into shares of Common Stock that, together with the number of shares of Common Stock owned (or deemed for bank regulatory purposes to be owned) by such holder and its affiliates as set forth in the notice of conversion, represent more than 4.9% of the Common Stock then outstanding. If at any time the Conversion Rate and the principal amount of this Security would result in a greater number of shares being issuable upon conversion, then for so long as such condition shall exist, upon exercise of the conversion right the holder shall receive (i) up to that number of shares of Common 2 Stock that, together with the number of shares of Common Stock owned (or deemed for bank regulatory purposes to be owned) by such holder and its affiliates as set forth in the notice of conversion, represent 4.9% of the Common Stock then outstanding, and (ii) an amount (in cash but not less than zero), payable in immediately available funds, determined pursuant to the formula: C = (P/CR - I) x CP where C = the cash amount receivable by the holder; P = the principal amount of this Security being converted; CR = the Conversion Rate; I = the number of shares issuable pursuant to clause (i) above; and CP = the Closing Price of the Common Stock on the date of conversion. (b) The Conversion Rate shall be subject to adjustments from time to time as follows: (1) In case the Company shall pay or make a dividend or other distribution on any class of capital stock of the Company payable in shares of Common Stock, the Conversion Rate in effect at the opening of business on the day following the Determination Date for such dividend or other distribution shall be increased by dividing such Conversion Rate by a fraction of which the numerator shall be the number of shares of Common Stock outstanding at the close of business on such Determination Date and the denominator shall be the sum of such number of shares and the total number of shares constituting such dividend or other distribution, such increase to become effective immediately after the opening of business on the day following such Determination Date. For the purposes of this paragraph (1), the number of shares of Common Stock at any time outstanding shall not include shares held in the treasury of the Company but shall include shares issuable in respect of scrip certificates issued in lieu of fractions of shares of Common Stock. The Company will not pay any dividend or make any distribution on shares of Common Stock held in the treasury of the Company. (2) Subject to the last sentence of paragraph (7) of this Section 2(b), in case the Company shall issue rights, options or warrants to all holders of its Common Stock entitling them to subscribe for or purchase shares of Common Stock at a price per share less than the current market price per share (determined as provided in paragraph (8) of this Section 2(b)) of the Common Stock on the Determination Date for such distribution, the Conversion Rate in effect at the opening of business on the day following such Determination Date shall be increased by dividing such Conversion Rate by a fraction of which the numerator shall be the number of shares of Common Stock outstanding at the close of business on such Determination Date plus the number of shares of Common Stock which the aggregate of the offering price of the total number of shares of Common Stock so offered for subscription or purchase would purchase at such current market price and the denominator shall be the number of shares of Common Stock outstanding at the close of business on such Determination Date plus the 3 number of shares of Common Stock so offered for subscription or purchase, such increase to become effective immediately after the opening of business on the day following such Determination Date. For the purposes of this paragraph (2), the number of shares of Common Stock at any time outstanding shall not include shares held in the treasury of the Company but shall include shares issuable in respect of scrip certificates issued in lieu of fractions of shares of Common Stock. The Company will not issue any rights, options or warrants in respect of shares of Common Stock held in the treasury of the Company. (3) In case outstanding shares of Common Stock shall be subdivided into a greater number of shares of Common Stock, the Conversion Rate in effect at the opening of business on the day following the day upon which such subdivision becomes effective shall be proportionately increased, and, conversely, in case outstanding shares of Common Stock shall each be combined into a smaller number of shares of Common Stock, the Conversion Rate in effect at the opening of business on the day following the day upon which such combination becomes effective shall be proportionately reduced, such increase or reduction, as the case may be, to become effective immediately after the opening of business on the day following the day upon which such subdivision or combination becomes effective. (4) Subject to the last sentence of paragraph (7) of this Section 2(b), in case the Company shall, by dividend or otherwise, distribute to all holders of its Common Stock evidences of its indebtedness, shares of any class of capital stock, or other property (including securities, but excluding (i) any rights, options or warrants referred to in paragraph (2) of this Section 2(b) (ii) any dividend or distribution paid exclusively in cash, (iii) any dividend or distribution referred to in paragraph (1) of this Section 2(b) and (iv) any merger or consolidation to which Section 2(h) applies), the Conversion Rate shall be adjusted so that the same shall equal the rate determined by dividing the Conversion Rate in effect immediately prior to the close of business on the Determination Date for such distribution by a fraction of which the numerator shall be the current market price per share (determined as provided in paragraph (8) of this Section 2(b)) of the Common Stock on such Determination Date less the then fair market value (as determined in good faith by the Board of Directors of the Company) of the portion of the assets, shares or evidences of indebtedness so distributed applicable to one share of Common Stock and the denominator shall be such current market price per share of the Common Stock, such adjustment to become effective immediately prior to the opening of business on the day following such Determination Date. If the Board of Directors determines the fair market value of any distribution for purposes of this paragraph (4) by reference to the actual or when issued trading market for any securities comprising such distribution, it must in doing so consider the prices in such market over the same period used in computing the current market price per share pursuant to paragraph (8) of this Section 2(b). (5) In case the Company shall, by dividend or otherwise, make a Cash Distribution, then, and in each such case, immediately after the close of business on the Determination Date for such Cash Distribution, the Conversion Rate shall be adjusted so that the same shall equal the rate determined by dividing the Conversion Rate in effect immediately prior to the close of business on such Determination Date by a fraction (a) the numerator of which shall be equal to the current market price per share (determined as provided in paragraph (8) of this Section 2(b)) of the Common Stock on such Determination Date less an amount equal to the quotient of 4 (1) the amount of such Cash Distribution divided by (2) the number of shares of Common Stock outstanding on such Determination Date and (b) the denominator of which shall be equal to the current market price per share (determined as provided in paragraph (8) of this Section 2(b)) of the Common Stock on such Determination Date. (6) In case the Company or any Subsidiary shall make an Excess Purchase Payment, then, and in each such case, immediately prior to the opening of business on the day after the tender offer in respect of which such Excess Purchase Payment is to be made expires, the Conversion Rate shall be adjusted so that the same shall equal the rate determined by dividing the Conversion Rate in effect immediately prior to the close of business on the Determination Date for such tender offer by a fraction (a) the numerator of which shall be equal to the current market price per share (determined as provided in paragraph (8) of this Section 2(b)) of the Common Stock on such Determination Date less an amount equal to the quotient of (A) the Excess Purchase Payment divided by (B) the number of shares of Common Stock outstanding (including any tendered shares) as of the Determination Date less the number of all shares validly tendered and not withdrawn as of the Determination Date and (b) the denominator of which shall be equal to the current market price per share (determined as provided in paragraph (8) of this Section 2(b)) of the Common Stock as of such Determination Date. (7) The reclassification of Common Stock into securities other than Common Stock (other than any reclassification upon a consolidation or merger to which Section 2(h) applies) shall be deemed to involve (a) a distribution of such securities other than Common Stock to all holders of Common Stock (and the effective date of such reclassification shall be deemed to be the Determination Date), and (b) a subdivision or combination, as the case may be, of the number of shares of Common Stock outstanding immediately prior to such reclassification into the number of shares of Common Stock outstanding immediately thereafter (and the effective date of such reclassification shall be deemed to be "the day upon which such subdivision becomes effective" or "the day upon which such combination becomes effective", as the case may be, and "the day upon which such subdivision or combination becomes effective"' within the meaning of paragraph (3) of this Section 2(b)). Rights or warrants issued by the Company to all holders of its Common Stock entitling the holders thereof to subscribe for or purchase shares of Common Stock, which rights or warrants (i) are deemed to be transferred with such shares of Common Stock, (ii) are not exercisable and (iii) are also issued in respect, of future issuances of Common Stock, in each case in clauses (i) through (iii) until the occurrence of a specified event or events ("Trigger Event"), shall for purposes of this Section 2(b) not be deemed issued until the occurrence of the earliest Trigger Event. (8) For the purpose of any computation under paragraphs (2), (4), (5) or (6) of this Section 2(b) the current market price per share of Common Stock on any date shall be calculated by the Company and be deemed to be the average of the daily Closing Prices for the five consecutive Trading Days selected by the Company commencing not more than 10 Trading Days before, and ending not later than, the earlier of the day in question and the day before the "ex" date with respect to the issuance or distribution requiring such computation. For purposes of this paragraph, the term "ex date", when used with respect to any issuance or distribution, means the first date on which the Common Stock trades regular way in the applicable securities 5 market or on the applicable securities exchange without the right to receive such issuance or distribution. (9) No adjustment in the Conversion Rate shall be required unless such adjustment (plus any adjustments not previously made by reason of this paragraph (9)) would require an increase or decrease of at least one percent in such rate; provided, however, that any adjustments which by reason of this paragraph (9) are not required to be made shall be carried forward and taken into account in any subsequent adjustment. All calculations under this Section 2 shall be made to the nearest cent or to the nearest one-hundredth of a share, as the case may be. (10) The Company may make such increases in the Conversion Rate, for the remaining term of the Securities or any shorter term, in addition to those required by paragraphs (1), (2), (3), (4), (5) and (6) of this Section 2(b) as it considers to be advisable in order to avoid or diminish any income tax to any holders of shares of Common Stock resulting from any dividend or distribution of stock or issuance of rights or warrants to purchase or subscribe for stock or from any event treated as such for income tax purposes. (c) Whenever the Conversion Rate is adjusted as provided in Section 2(b), the Company shall compute the adjusted Conversion Rate in accordance with Section 2(b) and shall prepare a certificate signed by the chief financial officer of the Company setting forth the adjusted Conversion Rate and showing in reasonable detail the facts upon which such adjustment is based, and shall promptly deliver such certificate to the holder of this Security. (d) In case: (1) the Company shall declare a dividend or other distribution on its Common Stock payable (i) otherwise than exclusively in cash or (ii) exclusively in cash in an amount that would require any adjustment pursuant to Section 2(b); or (2) the Company shall authorize the granting to the holders of its Common Stock of rights, options or warrants to subscribe for or purchase any shares of capital stock of any class or of any other rights; or (3) of any reclassification of the Common Stock of the Company, or of any consolidation, merger or share exchange to which the Company is a party and for which approval of any shareholders of the Company is required, or of the conveyance, sale, transfer or lease of all or substantially all of the assets of the Company; or (4) of the voluntary or involuntary dissolution, liquidation or winding up of the Company; or (5) the Company or any Subsidiary shall commence a tender offer for all or a portion of the Company's outstanding shares of Common Stock (or shall amend any such tender offer); 6 then the Company shall cause to be delivered to the holder of this Security, at least 20 days (or 10 days in any case specified in clause (1) or (2) above) prior to the applicable record, expiration or effective date hereinafter specified, a notice stating (x) the date on which a record is to be taken for the purpose of such dividend, distribution, rights, options or warrants, or, if a record is not to be taken, the date as of which the holders of Common Stock of record to be entitled to such dividend, distribution, rights, options or warrants are to be determined, (y) the date on which the right to make tenders under such tender offer expires or (z) the date on which such reclassification, consolidation, merger, conveyance, transfer, sale, lease, dissolution, liquidation or winding up is expected to become effective, and the date as of which it is expected that holders of Common Stock of record shall be entitled to exchange their shares of Common Stock for securities, cash or other property deliverable upon such reclassification, consolidation, merger, conveyance, transfer, sale, lease, dissolution, liquidation or winding up. Neither the failure to give such notice nor any defect therein shall affect the legality or validity of the proceedings described in clauses (1) through (5) of this Section 2(d). (e) The Company shall at all times reserve and keep available, free from preemptive rights, out of its authorized but unissued Common Stock, for the purpose of effecting the conversion of the Security, the full number of shares of Common Stock then issuable upon the conversion of this Security. (f) Except as provided in the next sentence, the Company will pay any and all taxes and duties that may be payable in respect of the issue or delivery of shares of Common Stock on conversion of this Security. The Company shall not, however, be required to pay any tax or duty which may be payable in respect of any transfer involved in the issue and delivery of shares of Common Stock in a name other than that of the holder of this Security, and no such issue or delivery shall be made unless and until the person requesting such issue has paid to the Company the amount of any such tax or duty, or has established to the satisfaction of the Company that such tax or duty has been paid. (g) The Company agrees that all shares of Common Stock which may be delivered upon conversion of the Security, upon such delivery, will have been duly authorized and validly issued and will be fully paid and nonassessable (and shall be issued out of the Company's authorized but unissued Common Stock) and, except as provided in Section 2(f), the Company will pay all taxes, liens and charges with respect to the issue thereof. (h) In ease of any consolidation of the Company with any other person, any merger of the Company into another person or of another person into the Company (other than a merger which does not result in any reclassification, conversion, exchange or cancellation of outstanding shares of Common Stock of the Company) or any conveyance, sale, transfer or lease of all or substantially all of the properties and assets of the Company, the person formed by such consolidation or resulting from such merger or which acquires such properties and assets, as the case may be, shall execute and deliver to the holder of this Security a supplemental agreement providing that such holder has the right thereafter, during the period this Security shall be convertible as specified in Section 2(a), to convert this Security only into the kind and amount of securities, cash and other property receivable upon such consolidation, merger, conveyance, sale, transfer or lease (including any Common Stock retainable) by a holder of the number of shares of Common Stock of the Company into which this Security might have been converted immediately prior to such consolidation, merger, conveyance, sale, transfer or 7 lease, assuming such holder of Common Stock of the Company (i) is not a person with which the Company consolidated, into which the Company merged or which merged into the Company or to which such conveyance, sale, transfer or lease was made, as the case may be (a "Constituent Person"), or an Affiliate of a Constituent Person and (ii) failed to exercise his rights of election, if any, as to the kind or amount of securities, cash and other property receivable upon such consolidation, merger, conveyance, sale, transfer or lease (provided that if the kind or amount of securities, cash and other property receivable upon such consolidation, merger, conveyance, sale, transfer, or lease is not the same for each share of Common Stock of the Company held immediately prior to such consolidation, merger, conveyance, sale, transfer or lease by others than a Constituent Person or an Affiliate thereof and in respect of which such rights of election shall not have been exercised ("Non-electing Share"), then for the purpose of this Section 2(h) the kind and amount of securities, cash and other property receivable upon such consolidation, merger, conveyance, sale, transfer or lease by the holders of each Non-electing Share shall be deemed to be the kind and amount so receivable per share by a plurality of the Non-electing Shares). Such supplemental agreement shall provide for adjustments which, for events subsequent to the effective date of such supplemental agreement, shall be as nearly equivalent as may be practicable to the adjustments provided for in this Section 2. The above provisions of this Section 2(h) shall similarly apply to successive consolidations, mergers, conveyances, sales, transfers or leases. In this paragraph, "securities of the kind receivable" upon such consolidation, merger, conveyance, transfer, sale or lease by a holder of Common Stock means securities that, among other things, are registered and transferable under the Securities Act, and listed and approved for quotation in all securities markets, in each case to the same extent as such securities so receivable by a holder of Common Stock. (i) The Company (i) will effect all registrations with, and obtain all approvals by, all governmental authorities that may be necessary under any United States Federal or state law (including the Securities Act of 1933, the Securities Exchange Act of 1934 and state securities and Blue Sky laws) for the shares of Common Stock issuable upon conversion of this Security to be lawfully issued and delivered as provided herein, and thereafter publicly traded (if permissible under such Securities Act) and qualified or listed as contemplated by clause (ii) (it being understood that the Company shall not be required to register the Common Stock issuable on conversion hereof under the Securities Act, except pursuant to the Registration Rights Agreement between the Company and the initial holder of this Security); and (ii) will list the shares of Common Stock required to be issued and delivered upon conversion of Securities, prior to such issuance or delivery, on each national Securities exchange on which outstanding Common Stock is listed or quoted at the time of such delivery, or if the Common Stock is not then listed on any securities exchange, to qualify the Common Stock for quotation on the Nasdaq National Market or such other inter-dealer quotation system, if any, on which the Common Stock is then quoted. (j) For purposes hereof: "Affiliate" of any specified person means any other person directly or indirectly controlling or controlled by or under direct or indirect common control with such specified person. For the purposes of this definition, "control", when used with respect to any specified person, means the power to direct the management and policies of such person, directly or indirectly, whether through the ownership of voting securities, by contract or otherwise; and the terms "controlling" and "controlled" have meanings correlative to the foregoing. 8 "Cash Distribution" means the distribution by the Company to all holders of its Common Stock of cash, other than any cash that is distributed upon a merger or consolidation to which Section 2(h) applies or as part of a distribution referred to in paragraph (4) of Section 2(b). "Closing Price" means, with respect to the Common Stock of the Company, for any day, the reported last sale price per share on the Nasdaq National Market, or, if the Common Stock is not admitted to trading on the Nasdaq National Market, on the principal national securities exchange or inter-dealer quotation system on which the Common Stock is listed or admitted to trading, or if not admitted to trading on the Nasdaq National Market, or listed or admitted to trading on any national securities exchange or inter-dealer quotation system, the average of the closing bid and asked prices per share in the over-the-counter market as furnished by any New York Stock Exchange member firm selected from time to time by the Company for that purpose. "Common Stock" means the Common Stock, par value $.01 per share, of the Company authorized at the date of this instrument as originally executed. Subject to the provisions of Section 2(h), shares issuable on conversion or repurchase of this Security shall include only shares of Common Stock or shares of any class or classes of common stock resulting from any reclassification or reclassifications thereof; provided, however, that if at any time there shall be more than one such resulting class, the shares so issuable on conversion of this Security shall include shares of all such classes, and the shares of each such class then so issuable shall be substantially in the proportion which the total number of shares of such class resulting from all such reclassifications bears to the total number of shares of all such classes resulting from all such reclassifications. "Determination Date" means, in the case of a dividend or other distribution, including the issuance of rights, options or warrants, to shareholders, the date fixed for the determination of shareholders entitled to receive such dividend or other distribution and, in the case of a tender offer, the last time that tenders could have been made pursuant to such tender offer. "Excess Purchase Payment" means the product of (A) the excess, if any, of (i) the amount of cash plus the fair market value (as determined in good faith by the Company's Board of Directors) of any non-cash consideration required to be paid with respect to one share of Common Stock acquired or to be acquired in a tender offer made by the Company or any subsidiary of the Company for all or any portion of the Common Stock over (ii) the current market price per share as of the last time that tenders could have been made pursuant to such tender offer and (B) the number of shares validly tendered and not withdrawn as of the Determination Date in respect of such tender offer. "Trading Day" means (i) if the Common Stock is admitted to trading on the Nasdaq National Market or any other system of automated dissemination of quotations of securities prices, a day on which trades may be effected through such system; (ii) if the Common Stock is listed or admitted for trading on the New York Stock Exchange or any other national securities exchange, a day on which such exchange is open for business; or (iii) if the Common Stock is not admitted to trading on the Nasdaq National Market or listed or admitted for trading on any national securities exchange or any other system of automated dissemination of quotation of securities prices, a day on which the Common Stock is traded regular way in the over-the-counter market and for which a closing bid and a closing asked price for the Common Stock are available. 9 3. Right to Require Repurchase. (a) In the event that a Change in Control (as hereinafter defined) shall occur, then the holder of this Security shall have the right, at such holder's option, to require the Company to repurchase, and upon the exercise of such right the Company shall repurchase, this Security, or any portion of the principal amount hereof that is equal to $1,000 or any integral multiple thereof, on the date (the "Repurchase Date") that is fifteen Trading Days after the date on which the Company gives notice thereof to the holder of this Security, at a purchase price equal to 100% of the principal amount of this Security to be repurchased plus interest accrued to the Repurchase Date (the "Repurchase Price"); provided, however, that installments of interest on this Security whose stated maturity is on or prior to the Repurchase Date shall be payable to the holder of this Security, or one or more predecessor Securities, registered as such on the relevant Record Date according to their terms. At the option of the Company, the Repurchase Price may be paid in cash or, subject to the fulfillment by the Company of the conditions set forth in Section 6 and subject to the limitations set forth therein, by delivery of shares of Common Stock having a fair market value equal to the Repurchase Price as described in Section 6. The Company agrees to give the holder of this Security notice of any Change in Control, by facsimile transmission confirmed in writing by overnight courier service, promptly and in any event within two Trading Days of the occurrence thereof. (b) To exercise a repurchase right, the holder shall deliver to the Company on or before the 10th trading day prior to the Repurchase Date, together with this Security, written notice of the holder's exercise of such right, which notice shall set forth the name of the holder, the number of shares of Common Stock then owned by such holder and its affiliates, the principal amount of this Security to be repurchased (and, if this Security is to be repurchased in part, the portion of the principal amount thereof to be repurchased and the name of the person in which the portion thereof to remain outstanding after such repurchase is to be registered) and a statement that an election to exercise the repurchase right is being made thereby, and, in the event that the Repurchase Price shall be paid in shares of Common Stock, the name or names (with addresses) in which the certificates for shares of Common Stock shall be issued. Such written notice shall be irrevocable, except that the right of the holder to convert this Security (or the portion hereof with respect to which the repurchase right is being exercised) shall continue until the close of business on the Repurchase Date (or if the Company elects to pay the Repurchase Price by delivery of shares of Common Stock, until the close of business on the Trading Day immediately preceding the first delivery of Common Stock in respect thereof). (c) In the event a repurchase right shall be exercised in accordance with the terms hereof, the Company shall pay or cause to be paid to the holder the Repurchase Price in cash or shares of Common Stock, as provided above, together with accrued and unpaid interest to the Repurchase Date; provided, however, that installments of interest that mature on or prior to the Repurchase Date shall be payable in cash, to the holders of this Security, or one or more predecessor Securities, registered as such at the close of business on the relevant regular record date. (d) If this Security (or portion thereof) is surrendered for repurchase and is not so paid on or prior to the Repurchase Date, the principal amount of this Security (or such portion hereof, as the case may be) shall, until paid, bear interest to the extent permitted by applicable law from the Repurchase Date at the rate per annum borne by this Security, and shall remain convertible into Common Stock until the principal of this Security (or portion thereof, as the case may be) shall have been paid or duly provided for. 10 (e) If this Security is to be repurchased only in part, it shall be surrendered to the Company at the Designated Office (with, if the Company so requires, due endorsement by, or a written instrument of transfer in form satisfactory to the Company duly executed by, the holder hereof or his attorney duly authorized in writing), and the Company shall execute and make available for delivery to the holder without service charge, a new Security or Securities, containing identical terms and conditions, each in an authorized denomination in aggregate principal amount equal to and in exchange for the unrepurchased portion of the principal of the Security so surrendered. (f) For purposes of this Section 3. (1) the term "beneficial owner" shall be determined in accordance with Rule 13d-3 promulgated by the Securities and Exchange Commission pursuant to the Securities Exchange Act of 1934; and (2) a "Change in Control" shall be deemed to have occurred at the time, after the original issuance of this Security, of: (i) the acquisition by any person of beneficial ownership, directly or indirectly, through a purchase, merger or other acquisition transaction or series of transactions, of shares of capital stock of the Company entitling such person to exercise 50% or more of the total voting power of all shares of capital stock of the Company entitled to vote generally in the elections of directors (any shares of voting stock of which such person is the beneficial owner that are not then outstanding being deemed outstanding for purposes of calculating such percentage) other than any such acquisition by the Company or any employee benefit plan of the Company; or (ii) any consolidation or merger of the Company with or into, any other person, any merger of another person with or into the Company, or any conveyance, transfer, sale, lease or other disposition of all or substantially all of the assets of the Company to another person (other than (a) any such transaction (x) which does not result in any reclassification, conversion, exchange or cancellation of outstanding shares of Common Stock and (y) pursuant to which holders of Common Stock immediately prior to such transaction have the entitlement to exercise, directly or indirectly, 50% or more of the total voting power of all shares of capital stock entitled to vote generally in the election of directors of the continuing or surviving person immediately after such transaction and (b) any merger which is effected solely to change the jurisdiction of incorporation of the Company and results in a reclassification, conversion or exchange of outstanding shares of Common Stock into solely shares of common stock); provided, however, that a Change in Control shall not be deemed to have occurred if the Closing Price for any five Trading Days within the period of 10 consecutive Trading Days (x) ending immediately after the later of the date of the Change in Control or the date of the public announcement of the Change in Control (in the case of a Change in Control under Clause (i) above) or (y) ending immediately prior to the date of the Change in Control (in the case of a Change in Control under Clause (ii) above) shall equal or exceed 105% of the Conversion Price in effect on each such Trading Day. 11 4. Events of Default. (a) "Event of Default", wherever used herein, means any one of the following events (whatever the reason for such Event of Default and whether it shall be voluntary or involuntary or be effected by operation of law or pursuant to any judgment, decree or order of any court or any order, rule or regulation of any administrative or governmental body): (1) default in the payment of any interest upon this Security when it becomes due and payable, and continuance of such default for a period of 30 days; or (2) default by the Company in the performance of its obligations in respect of any conversion of this Security (or any portion hereof) in accordance with Section 2; or (3) failure by the Company to give any notice of a Change of Control required to be delivered in accordance with Section 3(a); or (4) default in the performance, or breach, of any material covenant or warranty of the Company herein (other than a covenant or warranty a default in the performance or breach of which is specifically dealt with elsewhere in this Section 4(a)) and continuance of such default or breach for a period of 30 days after there has been given, by registered or certified mail, to the Company by the holder of this Security a written notice specifying such default or breach and requiring it to be remedied and stating that such notice is a "Notice of Default" hereunder; or (5) a default under any bond, debenture, note or other evidence of indebtedness for money borrowed by the Company, or under any agreement, mortgage, indenture or instrument under which there may be issued or by which there may be secured or evidenced any indebtedness for money borrowed by the Company, with a principal amount then outstanding in excess of $1,000,000, whether such indebtedness now exists or shall hereafter be created, which default shall constitute a failure to pay the principal of such indebtedness (in whole or in any part greater than $1,000,000) when due and payable or shall have resulted in such indebtedness (in whole or in any part greater than $1,000,000) becoming or being declared due and payable prior to the date on which it would otherwise have become due and payable, without such indebtedness having been discharged, or such acceleration having been rescinded or annulled, within a period of 15 days after there shall have been given, by registered or certified mail, to the Company by the holder of this Security a written notice specifying such default and requiring the Company to cause such indebtedness to be discharged or cause such acceleration to be rescinded or annulled and stating that such notice is a "Notice of Default" hereunder; or (6) the entry by a court having jurisdiction in the premises of (A) a decree or order for relief in respect of the Company in an involuntary case or proceeding under any applicable Federal or State bankruptcy, insolvency, reorganization or other similar law or (B) a decree or order adjudging the Company a bankrupt or insolvent, or approving as properly filed a petition seeking reorganization, arrangement, adjustment or composition of or in respect of the Company under any applicable Federal or State law, or appointing a custodian, receiver, liquidator, assignee, trustee, sequestrator or other similar official of the Company or of any substantial part of its property, or ordering the winding up or liquidation of its affairs, and the 12 continuance of any such decree or order for relief or any such other decree or order unstayed and in effect for a period of 60 consecutive days; or (7) the commencement by the Company of a voluntary case or proceeding under any applicable Federal or State bankruptcy, insolvency, reorganization or other similar law or of any other case or proceeding to be adjudicated a bankrupt or insolvent, or the consent by it to the entry of a decree or order for relief in respect of the Company in an involuntary case or proceeding under any applicable Federal or State bankruptcy, insolvency, reorganization or other similar law or to the commencement of any bankruptcy or insolvency case or proceeding against it, or the filing by it of a petition or answer or consent seeking reorganization or similar relief under any applicable Federal or State law, or the consent by it to the filing of such petition or to the appointment of or taking possession by a custodian, receiver, liquidator, assignee, trustee, sequestrator or other similar official of the Company or of any substantial part of its property, or the making by it of an assignment for the benefit of creditors, or the admission by it in writing of its inability to pay its debts generally as they become due, or the taking of corporate action by the Company in furtherance of any such action. (b) If an Event of Default (other than an Event of Default specified in Section 4(a)(6) or 4(a)(7)) occurs and is continuing, then in every such case the holder of this Security may declare the principal hereof to be due and payable immediately, by a notice in writing to the Company, and upon any such declaration such principal and all accrued interest thereon shall become immediately due and payable. If an Event of Default specified in Section 4(a)(6) or 4(a)(7) occurs and is continuing, the principal of, and accrued interest on, this Security shall ipso facto become immediately due and payable without any declaration or other act of the holders. 5. Consolidation, Merger, Etc. (a) The Company shall not consolidate with or merge into any other person or, directly or indirectly, convey, transfer, sell or lease all or substantially all of its properties and assets to any person, and the Company shall not permit any person to consolidate with or merge into the Company or, directly or indirectly, convey, transfer, sell or lease all or substantially all of its properties and assets to the Company, unless: (1) in case the Company shall consolidate with or merge into another person or convey, transfer, sell or lease all or substantially all of its properties and assets to any person, the person formed by such consolidation or into which the Company is merged or the person which acquires by conveyance, transfer or sale, or which leases, all or substantially all the properties and assets of the Company shall be a corporation, limited liability company, partnership or trust, shall be organized and validly existing under the laws of the United States of America, any State thereof or the District of Columbia and shall expressly assume, by an agreement supplemental hereto, executed and delivered to the holder of this Security in form satisfactory to the holder, the due and punctual payment of the principal of (and premium, if any) and interest on this Security and the performance or observance of every covenant of this Security on the part of the Company to be performed or observed, including the conversion rights provided herein (which shall thereafter relate to common stock of such successor, on a basis reasonably designed to preserve the economic value to the holder of this Security of such conversion rights); 13 (2) immediately after giving effect to such transaction and treating any indebtedness which becomes an obligation of the Company or a subsidiary of the Company as a result of such transaction as having been incurred by the Company or such subsidiary of the Company at the time of such transaction, no Event of Default, and no event which, after notice or lapse of time or both, would become an Event of Default, shall have happened and be continuing; (3) the Company has delivered to the holder of this Security an officers' certificate stating that such consolidation, merger, conveyance, transfer, sale or lease and, if a supplemental agreement is required in connection with such transaction, such supplemental agreement, comply with this Section and that all conditions precedent herein provided for relating to such transaction have been complied with; and (4) counsel for the Company has delivered to the holder of this Security an opinion of such counsel with respect to such consolidation, merger, conveyance, transfer, sale or lease, and if a supplemental agreement is required in connection with such transaction, such supplemental agreement, which opinion shall be, in form and substance, reasonably acceptable to such holder and its counsel. (b) Upon any consolidation of the Company with, or merger of the Company into, any other person or any conveyance, transfer, sale or lease of all or substantially all of the properties and assets of the Company in accordance with Section 5(a), the successor person formed by such consolidation or into which the Company is merged or to which such conveyance, transfer, sale or lease is made shall succeed to, and be substituted for, and may exercise every right and power of, the Company under this Security with the same effect as if such successor person had been named as the Company herein, and thereafter, except in the case of a lease, the predecessor person shall be relieved of all obligations and covenants under this Security. 6. Payment in Stock. (a) The Company may elect to pay any amount due hereunder in respect of interest or Repurchase Price in respect hereof by delivery of shares of Common Stock if and only if the following conditions have been satisfied: (1) Any such payment shall be made in five equal installments, on each of the five consecutive Trading Days ending on and including the third Trading Day immediately preceding the date when cash payment would otherwise be due, and the shares of Common Stock deliverable in payment of each such installment shall have a fair market value as of the date of such installment of not less than 20% of the amount of such payment due hereunder. For purposes of this Section 6, the fair market value of shares of Common Stock shall be equal to 95% of the Closing Price for the immediately preceding Trading Day; (2) In the event any shares of Common Stock to be issued in respect of such amount due hereunder require registration under any Federal securities law before such shares may be freely transferrable without being subject to any transfer restrictions under the Securities Act of 1933 upon issuance, such registration shall have been completed and shall have become effective prior to the date of the first such installment; 14 (3) In the event any shares of Common Stock to be issued in respect of such amount due hereunder require registration with or approval of any governmental authority under any State law or any other Federal law before such shares may be validly issued or delivered upon issuance, such registration shall have been completed or have become effective and such approval shall have been obtained, in each case, prior to the date of the first such installment; (4) The shares of Common Stock deliverable in payment of such amount due hereunder shall have been approved for quotation in the Nasdaq National Market immediately prior to the date of the first such installment; (5) All shares of Common Stock deliverable in payment of such amount due hereunder shall, upon issue, be duly and validly issued and fully paid and non-assessable and free of any preemptive rights; and (6) In respect of each such payment date, the Company shall have given the holder of this Security not less than 10 nor more than 15 Trading Days' notice of its election to effect payment in respect of such payment date by delivery of shares of Common Stock; provided that any such notice in respect of amounts payable on a Repurchase Date shall accompany the Company's notice of a Change of Control relating thereto. If all of the conditions set forth in this Section 6(a) are not satisfied in accordance with the terms thereof, any such amount due hereunder shall be paid by the Company only in cash. Notwithstanding the foregoing, at no time will the Company deliver shares of Common Stock to any holder in satisfaction of an obligation to pay interest or Repurchase Price if the number of shares so delivered, together with the number of shares of Common Stock owned (or deemed for bank regulatory purposes to be owned) by such holder and its affiliates as theretofore notified to the Company (in a notice delivered not less than five Trading Days prior to the relevant interest payment date, in the case of interest, or as set forth in the election of holder to require repurchase, in the case of Repurchase Price), represent more than 4.9% of the Common Stock then outstanding. If the limitation set forth in the previous sentence would apply to any payment of interest or Repurchase Price, the Company may elect (by notice to the holder delivered not less than three Trading Days prior to the relevant interest payment date, in the case of interest, or not less than eight Trading Days prior to the Repurchase Date, in the case of Repurchase Price) to satisfy a portion of such payment in shares of Common Stock (up to the maximum number of shares permitted under the limitation set forth in the previous sentence) and the balance in cash. (b) Any issuance of shares of Common Stock in respect of any installment due hereunder pursuant to this Section 6 shall be deemed to have been effected immediately prior to the close of business on the date of delivery of such installment and the person or persons in whose name or names any certificate or certificates for shares of Common Stock shall be issuable upon such delivery shall be deemed to have become on such date the holder or holders of record of the shares represented thereby; provided, however, that in case any installment shall be due on a date when the stock transfer books of the Company shall be closed, the person or persons in whose name or names the certificate or certificates for such shares are to be issued shall be deemed to have become the record holder or holders thereof for all purposes at the opening of business on the next succeeding day on 15 which such stock transfer books are open. No payment or adjustment shall be made for dividends or distributions on any Common Stock issued pursuant to this Section 6 declared prior to the relevant delivery date. (c) No fractions of shares shall be issued upon payment made in shares of Common Stock in respect of this Security. Instead of any fractional share of Common Stock which would otherwise be so issuable, the Company will round up to the next higher whole share. (d) Any issuance and delivery of certificates for shares of Common Stock pursuant to this Section 6 shall be made without charge to the holder of this Security for such certificates or for any tax or duty in respect of the issuance or delivery of such certificates or the securities represented thereby; provided, however, that the Company shall not be required to pay any tax or duty which may be payable in respect of any transfer involved in the issuance or delivery of certificates for shares of Common Stock in a name other than that of the holder of this Security, and no such issuance or delivery shall be made unless and until the person requesting such issuance or delivery has paid to the Company the amount of any such tax or duty or has established, to the satisfaction of the Company, that such tax or duty has been paid. 7. Other. (a) No provision of this Security shall alter or impair the obligation of the Company, which is absolute and unconditional, to pay the principal of, premium, if any, and interest on this Security at the times, places and rate, and in the coin or currency, herein prescribed or to convert this Security as herein provided. (b) The Company will give prompt written notice to the holder of Security of any change in the location of the Designated Office. (c) The transfer of this Security is registrable on the Security Register of the Company upon surrender of this Security for registration of transfer at the Designated Office, duly endorsed by, or accompanied by a written instrument of transfer in form satisfactory to the Company duly executed by, the holder hereof or his attorney duly authorized in writing, and thereupon one or more new Securities, of authorized denominations and for the same aggregate principal amount, will be issued to the designated transferee or transferees. Such Securities are issuable only in registered form without coupons in denominations of $1,000 and any integral multiple thereof. No service charge shall be made for any such registration of transfer, but the Company may require payment of a sum sufficient to recover any tax or other governmental charge payable in connection therewith. Prior to due presentation of this Security for registration of transfer, the Company and any agent of the Company may treat the person in whose name this Security is registered as the owner thereof for all purposes, whether or not this Security be overdue, and neither the Company nor any such agent shall be affected by notice to the contrary. Notwithstanding any other provision of this Security, this Security and the shares of Common Stock issuable upon conversion hereof may only be transferred by the holder of this Security (a) in the case of the Common Stock only, in a widely dispersed registered public offering; (b) to one or more accredited investors, in one or more transactions, any one of whom, after such purchase, would hold not more than 2 % of the shares of Common Stock then outstanding (assuming conversion of any portion of this Security so transferred); (c) to any person or entity that already controls more 16 than 50% of the voting securities of the Company prior to such transfer; or (d) in a transaction that complies with the volume and manner of sale restrictions of Rule 144 under the Securities Act of 1933. The holder of this Security, by acceptance thereof, shall be deemed to have agreed to the foregoing restriction on transfers. 17 (D) THIS SECURITY SHALL BE GOVERNED BY AND CONSTRUED IN ACCORDANCE WITH THE LAWS OF THE STATE OF NEW YORK, UNITED STATES OF AMERICA. IN WITNESS WHEREOF, the Company has caused this Security to be duly executed under its corporate seal. Dated: September __, 1998 CELGENE CORPORATION By: -------------------------------- Name: Title: Attest: - -------------------------------- Name: Title: ELECTION OF HOLDER TO REQUIRE REPURCHASE 1. Pursuant to Section 3(a) of this Security, the undersigned hereby elects to have all or a portion of this Security repurchased by the Company. 2. The undersigned hereby directs the Company to pay [choose one] (a) it or (b) Name: _______________________; address: _____________________; Social Security or Other Taxpayer Identification Number, if any: ___________________,in amount in cash or, at the Company's election (subject to the limitations set forth in the Security) Common Stock valued as set forth in the Security, equal to 100 % of the principal amount to be repurchased (as set forth below), plus interest accrued to the Repurchase Date, as provided herein. Dated: ------------------------------ ------------------------------ Signature Number of shares of Common Stock owned by the holder and its affiliates: ------------------------------ Principal amount to be repurchased (an integral multiple of $1,000): ------------------------------ Remaining principal amount following such repurchase (not less than $1,000): ------------------------------ NOTICE: The signature to the foregoing Election must correspond to the name as written upon the face of this Security in every particular, without alteration or any change whatsoever. CONVERSION NOTICE The undersigned holder of this Security hereby irrevocably exercises the option to convert this Security, or any portion of the principal amount hereof (which is an integral multiple of $1,000) below designated, into shares of Common Stock (subject to the limitation set forth in the second paragraph of Section 2(a) of the Security) in accordance with the terms of this Security, and directs that such shares, together with a check in payment for any fractional share and any Security representing any unconverted principal amount hereof, be delivered to and be registered in the name of the undersigned unless a different name has been indicated below. If shares of Common Stock or Securities are to be registered in the name of a person other than the undersigned, the undersigned will pay all transfer taxes payable with respect thereto. Any amount required to be paid by the undersigned on account of interest accompanies this Security. Dated: ------------------------------ ------------------------------ Signature Number of shares of Common Stock owned by the holder and its affiliates: ------------------------------ If shares or Securities are to be If only a portion of the Securities is registered in the name of a person to be converted, please indicate: other than the holder, please print such person's name and address: 1. Principal amount to be converted: $ ------------------------------ Name 2. Principal amount and denomination of Security representing unconverted principal amount to be issued: ------------------------------ Address Amount: $________ Denominations: $________ (any integral multiple of $1,000) ------------------------------ Social Security or other Taxpayer Identification Number, if any