TRIANGLE PHARMACEUTICALS, INC. SALARY INVESTMENT STOCK OPTION AGREEMENT RECITALS A. The Corporation has implemented a special salary investment stock option program under the Plan pursuant to which selected employees may, by prior irrevocable election, apply a portion of their base salary each year to the acquisition of a special stock option grant. B. Optionee has made the requisite election to apply a portion of his or her base salary to the acquisition of the special option, and this Agreement is executed pursuant to, and is intended to carry out the purposes of, the Plan in connection with the Corporation's grant of such special option to Optionee. C. All capitalized terms in this Agreement shall have the meaning assigned to them in the attached Appendix. NOW, THEREFORE, it is hereby agreed as follows: 1. GRANT OF OPTION. The Corporation hereby grants to Optionee, as of the Grant Date, a Non-Qualified Option to purchase up to the number of Option Shares specified in the Grant Notice. The Option Shares shall be purchasable from time to time during the option term specified in Paragraph 2 at the Exercise Price. 2. OPTION TERM. This option shall have a term of ten (10) years measured from the Grant Date and shall accordingly expire at the close of business on the Expiration Date, unless sooner terminated in accordance with Paragraph 5 or 6. 3. LIMITED TRANSFERABILITY. This option may, in connection with the Optionee's estate plan, be assigned in whole or in part during Optionee's lifetime to one or more members of the Optionee's immediate family or to a trust established for the exclusive benefit of one or more such family members. The assigned portion shall be exercisable only by the person or persons who acquire a proprietary interest in the option pursuant to such assignment. The terms applicable to the assigned portion shall be the same as those in effect for this option immediately prior to such assignment and shall be set forth in such documents issued to the assignee as the Corporation may deem appropriate. Should the Optionee die while holding this option, then this option shall be transferred in accordance with Optionee's will or the laws of descent and distribution. 4. DATES OF EXERCISE. This option shall become exercisable for the Option Shares in a series of successive monthly installments as specified in the Grant Notice. As the option becomes exercisable for one or more of those installments, the installments shall accumulate and the option shall remain exercisable for the accumulated installments until the Expiration Date or sooner termination of the option term under Paragraph 5 or 6. 5. CESSATION OF SERVICE. The option term specified in Paragraph 2 shall terminate (and this option shall cease to be outstanding) prior to the Expiration Date should any of the following provisions become applicable: (i) Should Optionee cease to remain in Service for any reason while this option is outstanding, then the exercise period for this option shall be reduced to a period of three (3) years measured from the date of such cessation of Service, but in no event shall this option be exercisable at any time after the Expiration Date. (ii) Should Optionee die while this option is outstanding, then the personal representative of Optionee's estate or the person or persons to whom the option is transferred pursuant to Optionee's will or in accordance with the laws of descent and distribution shall have the right to exercise this option. Such right shall lapse and this option shall cease to be outstanding upon the EARLIER of (i) the expiration of the three (3)-year period measured from the date of Optionee's cessation of Service or (ii) the Expiration Date. (iii) During the applicable post-Service exercise period, this option may not be exercised in the aggregate for more than the number of Option Shares for which the option is exercisable at the time of Optionee's cessation of Service. Upon the expiration of such limited exercise period or (if earlier) upon the Expiration Date, this option shall terminate and cease to be outstanding for any exercisable Option Shares for which the option has not been exercised. However, this option shall immediately, upon Optionee's cessation of Service for any reason, terminate and cease to be outstanding with respect to any and all Option Shares for which the option is not otherwise at that time exercisable. (iv) In the event of a Corporate Transaction or Change in Control, the provisions of Paragraph 6 or Paragraph 7 shall govern the period for which this option is to remain exercisable following Optionee's cessation of Service and shall supersede any provisions to the contrary in this Paragraph 5. 6. CORPORATE TRANSACTION. 2. (a) This option, to the extent outstanding at the time of a Corporate Transaction but not otherwise fully exercisable for all the Option Shares, shall automatically accelerate so that this option shall, immediately prior to the effective date of such Corporate Transaction, become exercisable for all the Option Shares at the time subject to this option and may be exercised for any or all of those Option Shares as fully-vested shares of Common Stock. (b) This option shall be assumed by the successor corporation (or parent thereof) in connection with such Corporate Transaction and shall be appropriately adjusted, immediately after such Corporate Transaction, to apply to the number and class of securities which would have been issuable to Optionee in consummation of such Corporate Transaction had the option been exercised immediately prior to such Corporate Transaction, and appropriate adjustments shall also be made to the Exercise Price, PROVIDED the aggregate Exercise Price shall remain the same. (c) This option, as so accelerated and assumed, shall remain exercisable until the EARLIER of (i) the expiration of the three (3)-year period measured from the date of Optionee's cessation of Service or (ii) the specified Expiration Date. (d) This Agreement shall not in any way affect the right of the Corporation to adjust, reclassify, reorganize or otherwise change its capital or business structure or to merge, consolidate, dissolve, liquidate or sell or transfer all or any part of its business or assets. 7. CHANGE IN CONTROL. All Option Shares subject to this option at the time of a Change in Control but not otherwise vested shall automatically vest so that this option shall, immediately prior to the effective date of such Change in Control, become fully exercisable for all of the Option Shares at the time subject to this option and may be exercised for all or any portion of such shares as fully-vested shares of Common Stock. This option shall remain exercisable for such fully-vested Option Shares until the EARLIEST to occur of (i) the specified Expiration Date, (ii) the expiration of the three (3)-year period measured from the date of Optionee's cessation of Service. 8. STOCKHOLDER RIGHTS. The holder of this option shall not have any stockholder rights with respect to the Option Shares until such person shall have exercised the option, paid the Exercise Price and become a holder of record of the purchased shares. 9. ADJUSTMENT IN OPTION SHARES. Should any change be made to the Common Stock by reason of any stock split, stock dividend, recapitalization, combination of shares, exchange of shares or other change affecting the outstanding Common Stock as a class without the Corporation's receipt of consideration, appropriate adjustments shall be made to (i) the number and/or class of securities subject to this option and (ii) the Exercise Price in order to reflect such change and thereby preclude a dilution or enlargement of benefits hereunder. 3. 10. MANNER OF EXERCISING OPTION. (a) In order to exercise this option with respect to all or any part of the Option Shares for which this option is at the time exercisable, Optionee (or any other person or persons exercising the option) must take the following actions: (i) Execute and deliver to the Corporation a Notice of Exercise for the number of Option Shares for which the option is exercised. (ii) Pay the aggregate Exercise Price for the purchased shares in one or more of the following forms: (A) cash or check made payable to the Corporation; (B) shares of Common Stock held by Optionee (or any other person or persons exercising the option) for the requisite period necessary to avoid a charge to the Corporation's earnings for financial reporting purposes and valued at Fair Market Value on the Exercise Date; or (C) through a special sale and remittance procedure pursuant to which Optionee (or any other person or persons exercising the option) shall concurrently provide irrevocable written instructions (I) to a Corporation-designated brokerage firm to effect the immediate sale of the purchased shares and remit to the Corporation, out of the sale proceeds available on the settlement date, sufficient funds to cover the aggregate Exercise Price payable for the purchased shares plus all applicable Federal, state and local income and employment taxes required to be withheld by the Corporation by reason of such exercise and (II) to the Corporation to deliver the certificates for the purchased shares directly to such brokerage firm in order to complete the sale. Except to the extent the sale and remittance procedure is utilized in connection with the option exercise, payment of the Exercise Price must accompany the Notice of Exercise. (iii) Furnish to the Corporation appropriate documentation that the person or persons exercising the option (if other than Optionee) have the right to exercise this option. (iv) Make appropriate arrangements with the Corporation (or Parent or Subsidiary employing or retaining Optionee) for the 4. satisfaction of all Federal, state and local income and employment tax withholding requirements applicable to the option exercise. (b) As soon as practical after the Exercise Date, the Corporation shall issue to or on behalf of Optionee (or any other person or persons exercising this option) a certificate for the purchased Option Shares. (c) In no event may this option be exercised for any fractional shares. 11. COMPLIANCE WITH LAWS AND REGULATIONS. (a) The exercise of this option and the issuance of the Option Shares upon such exercise shall be subject to compliance by the Corporation and Optionee with all applicable requirements of law relating thereto and with all applicable regulations of any stock exchange (or the Nasdaq National Market, if applicable) on which the Common Stock may be listed for trading at the time of such exercise and issuance. (b) The inability of the Corporation to obtain approval from any regulatory body having authority deemed by the Corporation to be necessary to the lawful issuance and sale of any Common Stock pursuant to this option shall relieve the Corporation of any liability with respect to the non-issuance or sale of the Common Stock as to which such approval shall not have been obtained. The Corporation, however, shall use its best efforts to obtain all such approvals. 12. SUCCESSORS AND ASSIGNS. Except to the extent otherwise provided in Paragraph 3, the provisions of this Agreement shall inure to the benefit of, and be binding upon, the Corporation and its successors and assigns and Optionee, Optionee's assigns and the legal representatives, heirs and legatees of Optionee's estate. 13. NOTICES. Any notice required to be given or delivered to the Corporation under the terms of this Agreement shall be in writing and addressed to the Corporation at its principal corporate offices. Any notice required to be given or delivered to Optionee shall be in writing and addressed to Optionee at the address indicated below Optionee's signature line on the Grant Notice. All notices shall be deemed effective upon personal delivery or upon deposit in the U.S. mail, postage prepaid and properly addressed to the party to be notified. 14. CONSTRUCTION. This Agreement and the option evidenced hereby are made and granted pursuant to the Plan and are in all respects limited by and subject to the terms of the Plan. All decisions of the Plan Administrator with respect to any question or issue arising under the Plan or this Agreement shall be conclusive and binding on all persons having an interest in this option. 5. 15. GOVERNING LAW. The interpretation, performance and enforcement of this Agreement shall be governed by the laws of the State of California without resort to that State's conflict-of-laws rules. 16. EXCESS SHARES. If the Option Shares covered by this Agreement exceed, as of the Grant Date, the number of shares of Common Stock which may without stockholder approval be issued under the Plan, then this option shall be void with respect to such excess shares, unless stockholder approval of an amendment sufficiently increasing the number of shares of Common Stock issuable under the Plan is obtained in accordance with the provisions of the Plan. 17. LEAVE OF ABSENCE. The following provisions shall apply upon the Optionee's commencement of an authorized leave of absence: (i) The exercise schedule in effect under the Grant Notice shall be frozen as of the first day of the authorized leave, and the option shall not become exercisable for any additional installments of the Option Shares during the period Optionee remains on such leave. (ii) Should Optionee resume active Employee status within sixty (60) days after the start date of the authorized leave, Optionee shall, for purposes of the exercise schedule set forth in the Grant Notice, receive Service credit for the entire period of such leave. If Optionee does not resume active Employee status within such sixty (60)-day period, then Service credit shall be given for the period of the leave. (iii) If the option is designated as an Incentive Stock Option in the Grant Notice, then the following additional provision shall apply: If the leave of absence continues for more than ninety (90) days, then the option shall automatically convert to a non-qualified option under the federal tax laws on the ninety-first (91st) day of such leave, unless the Optionee's reemployment rights are guaranteed by statute or by written agreement. Following any such conversion of the option, all subsequent exercises of such option, whether effected before or after Optionee's return to active Employee status, shall result in an immediate taxable event, and the Corporation shall be required to collect from Optionee the federal, state and local income and employment withholding taxes applicable to such exercise. (iv) In no event shall this option become exercisable for any additional Option Shares or otherwise remain outstanding if 6. Optionee does not resume Employee status prior to the Expiration Date of the option term. 7. APPENDIX The following definitions shall be in effect under the Agreement: A. AGREEMENT shall mean this Salary Investment Stock Option Agreement. B. BOARD shall mean the Corporation's Board of Directors. C. CODE shall mean the Internal Revenue Code of 1986, as amended. D. COMMON STOCK shall mean the Corporation's common stock. E. CORPORATE TRANSACTION shall mean either of the following stockholder-approved transactions to which the Corporation is a party: (i) a merger or consolidation in which securities possessing more than fifty percent (50%) of the total combined voting power of the Corporation's outstanding securities are transferred to a person or persons different from the persons holding those securities immediately prior to such transaction, or (ii) the sale, transfer or other disposition of all or substantially all of the Corporation's assets in complete liquidation or dissolution of the Corporation. F. CORPORATION shall mean Triangle Pharmaceuticals, Inc., a Delaware corporation. G. EMPLOYEE shall mean an individual who is in the employ of the Corporation (or any Parent or Subsidiary), subject to the control and direction of the employer entity as to both the work to be performed and the manner and method of performance. H. EXERCISE DATE shall mean the date on which the option shall have been exercised in accordance with Paragraph 9 of the Agreement. I. EXERCISE PRICE shall mean the exercise price per share as specified in the Grant Notice. J. EXPIRATION DATE shall mean the date on which the option expires as specified in the Grant Notice. K. FAIR MARKET VALUE per share of Common Stock on any relevant date shall be determined in accordance with the following provisions: (i) If the Common Stock is at the time traded on the Nasdaq National Market, then the Fair Market Value shall be the closing selling price per share of A-1. Common Stock on the date in question, as such price is reported by the National Association of Securities Dealers on the Nasdaq National Market or any successor system. If there are no selling prices quoted for the Common Stock on the date in question, then the Fair Market Value shall be the closing selling price on the last preceding date for which such quotation exists. (ii) If the Common Stock is at the time listed on any Stock Exchange, then the Fair Market Value shall be the closing selling price per share of Common Stock on the date in question on the Stock Exchange determined by the Plan Administrator to be the primary market for the Common Stock, as such price is officially quoted in the composite tape of transactions on such exchange. If there are no selling prices quoted for the Common Stock on the date in question, then the Fair Market Value shall be the closing selling price on the last preceding date for which such quotation exists. L. GRANT DATE shall mean the date of grant of the option as specified in the Grant Notice. M. GRANT NOTICE shall mean the Notice of Grant of Stock Option under the Salary Investment Option Grant Program accompanying the Agreement, pursuant to which Optionee has been informed of the basic terms of the option evidenced hereby. N. NON-QUALIFIED OPTION shall mean an option not intended to satisfy the requirements of Code Section 422. O. NOTICE OF EXERCISE shall mean the written notice of the option exercise on the form provided by the Corporation for such purpose. P. OPTION SHARES shall mean the number of shares of Common Stock subject to the option as specified in the Grant Notice. Q. OPTIONEE shall mean the person to whom the option is granted as specified in the Grant Notice. R. PARENT shall mean any corporation (other than the Corporation) in an unbroken chain of corporations ending with the Corporation, provided each corporation in the unbroken chain (other than the Corporation) owns, at the time of the determination, stock possessing fifty percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations in such chain. S. PERMANENT DISABILITY shall mean the inability of Optionee to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment which is expected to result in death or has lasted or can be expected to last for a continuous period of twelve (12) months or more. A-2. T. PLAN shall mean the Corporation's 1996 Stock Incentive Plan. U. PLAN ADMINISTRATOR shall mean either the Board or a committee of Board members, to the extent the committee is at the time responsible for the administration of the Plan. V. SERVICE shall mean the Optionee's performance of services for the Corporation (or any Parent or Subsidiary) in the capacity of an Employee, a non-employee member of the board of directors or a consultant or independent advisor. W. STOCK EXCHANGE shall mean the American Stock Exchange or the New York Stock Exchange. X. SUBSIDIARY shall mean any corporation (other than the Corporation) in an unbroken chain of corporations beginning with the Corporation, provided each corporation (other than the last corporation) in the unbroken chain owns, at the time of the determination, stock possessing fifty percent (50%) or more of the total combined voting power of all classes of stock in one of the other corporations in such chain. A-3.