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EXHIBIT 99.1

RIGEL PHARMACEUTICALS, INC.

2001 NON-OFFICER EQUITY INCENTIVE PLAN

ADOPTED JULY 19, 2001
STOCKHOLDER APPROVAL NOT REQUIRED

1. PURPOSES.

    (a) Eligible Stock Award Recipients. The persons eligible to receive Stock Awards are the Employees (other than Officers) and Consultants of the Company and its Affiliates.

    (b) Available Stock Awards. The purpose of the Plan is to provide a means by which eligible recipients of Stock Awards may be given an opportunity to benefit from increases in value of the Common Stock through the granting of the following Stock Awards: (i) Nonstatutory Stock Options, (ii) stock bonus awards and (iii) rights to acquire restricted stock.

    (c) General Purpose. The Company, by means of the Plan, seeks to retain the services of the group of persons eligible to receive Stock Awards, to secure and retain the services of new members of this group and to provide incentives for such persons to exert maximum efforts for the success of the Company and its Affiliates.

2. DEFINITIONS.

    (a) "Affiliate" means any parent corporation or subsidiary corporation of the Company, whether now or hereafter existing, as those terms are defined in Sections 424(e) and (f), respectively, of the Code.

    (b) "Board" means the Board of Directors of the Company.

    (c) "Code" means the Internal Revenue Code of 1986, as amended.

    (d) "Committee" means a committee of one or more members of the Board appointed by the Board in accordance with Section 3(c).

    (e) "Common Stock" means the common stock of the Company.

    (f)  "Company" means Rigel Pharmaceuticals, Inc., a Delaware corporation.

    (g) "Consultant" means any person, including an advisor, engaged by the Company or an Affiliate to render consulting or advisory services and who is compensated for such services. However, the term "Consultant" shall not include either Directors who are not compensated by the Company for their services as Directors or Directors who are merely paid a director's fee by the Company for their services as Directors.

    (h) "Continuous Service" means that the Participant's service with the Company or an Affiliate, whether as an Employee, Director or Consultant, is not interrupted or terminated. The Participant's Continuous Service shall not be deemed to have terminated merely because of a change in the capacity in which the Participant renders service to the Company or an Affiliate as an Employee, Consultant or Director or a change in the entity for which the Participant renders such service, provided that there is no interruption or termination of the Participant's Continuous Service. For example, a change in status from an Employee of the Company to a Consultant of an Affiliate or a Director will not constitute an interruption of Continuous Service. The Board or the chief executive officer of the Company, in that party's sole discretion, may determine whether Continuous Service shall be considered interrupted in

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the case of any leave of absence approved by that party, including sick leave, military leave or any other personal leave.

    (i)  "Director" means a member of the Board of Directors of the Company.

    (j)  "Disability" means the inability of a person, in the opinion of a qualified physician acceptable to the Company, to perform the major duties of such person's position with the Company or with an Affiliate because of the sickness or injury of such person.

    (k) "Employee" means any person employed by the Company or an Affiliate. Mere service as a Director or payment of a director's fee by the Company or an Affiliate shall not be sufficient to constitute "employment" by the Company or an Affiliate.

    (l)  "Exchange Act" means the Securities Exchange Act of 1934, as amended.

    (m) "Fair Market Value" means, as of any date, the value of the Common Stock determined as follows:

    (n) "Non-Employee Director" means a Director who either (i) is not a current Employee or Officer of the Company or its parent or a subsidiary, does not receive compensation (directly or indirectly) from the Company or its parent or a subsidiary for services rendered as a consultant or in any capacity other than as a Director (except for an amount as to which disclosure would not be required under Item 404(a) of Regulation S-K promulgated under the federal securities laws ("Regulation S-K")), does not possess an interest in any other transaction as to which disclosure would be required under Item 404(a) of Regulation S-K and is not engaged in a business relationship as to which disclosure would be required under Item 404(b) of Regulation S-K; or (ii) is otherwise considered a "non-employee director" for purposes of Rule 16b-3.

    (o) "Nonstatutory Stock Option" means an Option not intended to qualify as an "incentive stock option" within the meaning of Section 422 of the Code and the regulations promulgated thereunder.

    (p) "Officer" means a person who possesses the authority of an "officer" as that term is used in Rule 4460(i)(1)(A) of the Rules of the National Association of Securities Dealers, Inc. For purposes of the Plan, a person employed by the Company in the position of "Vice President" or higher shall be classified as an "Officer" unless the Board or Committee expressly finds that such person does not possess the authority of an "officer" as that term is used in Rule 4460(i)(1)(A) of the Rules of the National Association of Securities Dealers, Inc.

    (q) "Option" means a Nonstatutory Stock Option granted pursuant to the Plan.

    (r) "Option Agreement" means a written agreement between the Company and an Optionholder evidencing the terms and conditions of an individual Option grant. Each Option Agreement shall be subject to the terms and conditions of the Plan.

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    (s) "Optionholder" means a person to whom an Option is granted pursuant to the Plan or, if applicable, such other person who holds an outstanding Option.

    (t) "Participant" means a person to whom a Stock Award is granted pursuant to the Plan or, if applicable, such other person who holds an outstanding Stock Award.

    (u) "Plan" means this Rigel Pharmaceuticals, Inc. 2001 Non-Officer Equity Incentive Plan.

    (v) "Rule 16b-3" means Rule 16b-3 promulgated under the Exchange Act or any successor to Rule 16b-3, as in effect from time to time.

    (w) "Securities Act" means the Securities Act of 1933, as amended.

    (x) "Stock Award" means any right granted under the Plan, including an Option, a restricted stock purchase award and a stock bonus award.

    (y) "Stock Award Agreement" means a written agreement between the Company and a holder of a Stock Award evidencing the terms and conditions of an individual Stock Award grant. Each Stock Award Agreement shall be subject to the terms and conditions of the Plan.

3. ADMINISTRATION.

    (a) Administration by Board. The Board shall administer the Plan unless and until the Board delegates administration to a Committee, as provided in Section 3(c).

    (b) Powers of Board. The Board shall have the power, subject to, and within the limitations of, the express provisions of the Plan:

    (c) Delegation to Committee.

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    (d) Effect of Board's Decision. All determinations, interpretations and constructions made by the Board in good faith shall not be subject to review by any person and shall be final, binding and conclusive on all persons.

4. SHARES SUBJECT TO THE PLAN.

    (a) Share Reserve. Subject to the provisions of Section 11 relating to adjustments upon changes in Common Stock, the Common Stock that may be issued pursuant to Stock Awards shall not exceed in the aggregate three million five hundred thousand (3,500,000) shares of Common Stock.

    (b) Reversion of Shares to the Share Reserve. If any Nonstatutory Stock Option shall for any reason expire or otherwise terminate, in whole or in part, without having been exercised in full, the shares of Common Stock not acquired under such Nonstatutory Stock Option shall revert to and again become available for issuance under the Plan.

    (c) Source of Shares. The shares of Common Stock subject to the Plan may be unissued shares or reacquired shares, bought on the market or otherwise.

5. ELIGIBILITY.

    (a) Eligibility for Specific Stock Awards. Stock Awards may be granted to Employees, who are not Officers, and Consultants; provided, however, that Officers who are not previously employed by the Company may be granted Stock Awards as an inducement essential to such individuals entering into employment contracts with the Company.

    (b) Consultants.

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6. OPTION PROVISIONS.

    Each Option shall be in such form and shall contain such terms and conditions as the Board shall deem appropriate. The provisions of separate Options shall include (through incorporation of provisions hereof by reference in the Option or otherwise) the substance of each of the following provisions:

    (a) Term. The term of an Option shall not exceed 10 years, either at the time of grant of the Option or as the Option may be amended thereafter.

    (b) Exercise Price of a Nonstatutory Stock Option. The exercise price of each Nonstatutory Stock Option shall be not less than the Fair Market Value of the Common Stock subject to the Option on the date the Option is granted.

    (c) Consideration. The purchase price of Common Stock acquired pursuant to an Option shall be paid, to the extent permitted by applicable statutes and regulations, either (i) in cash or by check at the time the Option is exercised or (ii) at the discretion of the Board at the time of the grant of the Option or at any time prior to the time of exercise in the case of a Nonstatutory Stock Option (1) by delivery to the Company of other Common Stock, (2) according to a deferred payment or other similar arrangement with the Optionholder or (3) in any other form of legal consideration that may be acceptable to the Board. Unless otherwise specifically provided in the Option, the purchase price of Common Stock acquired pursuant to an Option that is paid by delivery to the Company of other Common Stock acquired, directly or indirectly from the Company, shall be paid only by shares of the Common Stock of the Company that have been held for more than six (6) months (or such longer or shorter period of time required to avoid a charge to earnings for financial accounting purposes). At any time that the Company is incorporated in Delaware, payment of the Common Stock's "par value," as defined in the Delaware General Corporation Law, shall not be made by deferred payment.

    In the case of any deferred payment arrangement, interest shall be compounded at least annually and shall be charged at the market rate of interest necessary to avoid a charge to earnings for financial accounting purposes.

    (d) Transferability of a Nonstatutory Stock Option. A Nonstatutory Stock Option shall not be transferable except by will or by the laws of descent and distribution and shall be exercisable during the lifetime of the Optionholder only by the Optionholder. Notwithstanding the foregoing, the Optionholder may, by delivering written notice to the Company, in a form satisfactory to the Company, designate a third party who, in the event of the death of the Optionholder, shall thereafter be entitled to exercise the Option.

    (e) Vesting Generally. Each Option shall be evidenced by an Option Agreement executed by the Company and the Optionholder. The total number of shares of Common Stock subject to an Option may vest and therefore become exercisable as set-forth in the Option Agreement. The Option may be subject to such other terms and conditions on the time or times when it may be exercised (which may be based on performance or other criteria) as the Board may deem appropriate. The provisions of this Section 6(e) are subject to any Option provisions governing the minimum number of shares of Common Stock as to which an Option may be exercised.

    (f)  Termination of Continuous Service. In the event an Optionholder's Continuous Service terminates for any reason other than upon the Optionholder's death or Disability, the Optionholder may exercise his or her Option (to the extent that the Optionholder was entitled to exercise such Option as of the date of termination or as otherwise permitted by the Company) but only within such period of time ending on the earlier of (i) the three (3) months following such termination (or such longer or shorter period specified in the Option Agreement), or (ii) the expiration of the term of the Option as set forth in the Option Agreement. If, after termination, the Optionholder does not exercise his or her Option within the time specified in the Option Agreement, the Option shall terminate.

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    (g) Extension of Termination Date. An Optionholder's Option Agreement may also provide that if the exercise of the Option following the termination of the Optionholder's Continuous Service (other than upon the Optionholder's death or Disability) would be prohibited at any time solely because the issuance of shares of Common Stock would violate the registration requirements under the Securities Act or similar requirements of applicable law of another jurisdiction to which the Option is subject, then the Option shall terminate on the earlier of (i) the expiration of the term of the Option set forth in the Option Agreement, or (ii) the expiration of a period of three (3) months after the termination of the Optionholder's Continuous Service during which the exercise of the Option would not be in violation of such registration requirements or similar requirements.

    (h) Disability of Optionholder. In the event that an Optionholder's Continuous Service terminates as a result of the Optionholder's Disability, the Optionholder may exercise his or her Option (to the extent that the Optionholder was entitled to exercise such Option as of the date of termination or as otherwise permitted by the Company), but only within such period of time ending on the earlier of (i) the twelve (12) months following such termination (or such longer or shorter period specified in the Option Agreement) or (ii) the expiration of the term of the Option as set forth in the Option Agreement. If, after termination, the Optionholder does not exercise his or her Option within the time specified herein, the Option shall terminate.

    (i)  Death of Optionholder. In the event (i) an Optionholder's Continuous Service terminates as a result of the Optionholder's death or (ii) the Optionholder dies within the period (if any) specified in the Option Agreement after the termination of the Optionholder's Continuous Service for a reason other than death, then the Option may be exercised (to the extent the Optionholder was entitled to exercise such Option as of the date of death or as otherwise permitted by the Company) by the Optionholder's estate, by a person who acquired the right to exercise the Option by bequest or inheritance or by a person designated to exercise the Option upon the Optionholder's death pursuant to Section 6(d), but only within the period ending on the earlier of (1) the date eighteen (18) months following the date of death (or such longer or shorter period specified in the Option Agreement) or (2) the expiration of the term of such Option as set forth in the Option Agreement. If, after death, the Option is not exercised within the time specified herein, the Option shall terminate.

    (j)  Early Exercise. The Option may include a provision whereby the Optionholder may elect at any time before the Optionholder's Continuous Service terminates to exercise the Option as to any part or all of the shares of Common Stock subject to the Option prior to the full vesting of the Option. Any unvested shares of Common Stock so purchased may be subject to a repurchase option in favor of the Company or to any other restriction the Board determines to be appropriate.

7. PROVISIONS OF STOCK AWARDS OTHER THAN OPTIONS.

    (a) Stock Bonus Awards. Each stock bonus agreement shall be in such form and shall contain such terms and conditions as the Board shall deem appropriate. The terms and conditions of stock bonus agreements may change from time to time, and the terms and conditions of separate stock bonus agreements shall include (through incorporation of provisions hereof by reference in the agreement or otherwise) the substance of each of the following provisions:

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    (b) Restricted Stock Purchase Awards. Each restricted stock purchase agreement shall be in such form and shall contain such terms and conditions as the Board shall deem appropriate. The terms and conditions of the restricted stock purchase agreements may change from time to time, and the terms and conditions of separate restricted stock purchase agreements need not be identical, but each restricted stock purchase agreement shall include (through incorporation of provisions hereof by reference in the agreement or otherwise) the substance of each of the following provisions:

8. COVENANTS OF THE COMPANY.

    (a) Availability of Shares. During the terms of the Stock Awards, the Company shall keep available at all times the number of shares of Common Stock required to satisfy such Stock Awards.

    (b) Securities Law Compliance. The Company shall seek to obtain from each regulatory commission or agency having jurisdiction over the Plan such authority as may be required to grant Stock Awards and to issue and sell shares of Common Stock upon exercise of the Stock Awards; provided, however, that this undertaking shall not require the Company to register under the Securities Act the Plan, any Stock Award or any Common Stock issued or issuable pursuant to any such Stock Award. If, after reasonable efforts, the Company is unable to obtain from any such regulatory commission or agency the authority which counsel for the Company deems necessary for the lawful

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issuance and sale of Common Stock under the Plan, the Company shall be relieved from any liability for failure to grant Stock Awards in compliance with applicable law or to issue and sell Common Stock upon exercise of such Stock Awards unless and until such authority is obtained.

9. USE OF PROCEEDS FROM STOCK.

    Proceeds from the sale of Common Stock pursuant to Stock Awards shall constitute general funds of the Company.

10. MISCELLANEOUS.

    (a) Stockholder Rights. No Participant shall be deemed to be the holder of, or to have any of the rights of a holder with respect to, any shares of Common Stock subject to such Stock Award unless and until such Participant has satisfied all requirements for exercise of the Stock Award pursuant to its terms.

    (b) No Employment or other Service Rights. Nothing in the Plan or any instrument executed or Stock Award granted pursuant thereto shall confer upon any Participant any right to continue to serve the Company or an Affiliate in the capacity in effect at the time the Stock Award was granted or shall affect the right of the Company or an Affiliate to terminate (i) the employment of an Employee with or without notice and with or without cause, (ii) the service of a Consultant pursuant to the terms of such Consultant's agreement with the Company or an Affiliate or (iii) the service of a Director pursuant to the Bylaws of the Company or an Affiliate, and any applicable provisions of the corporate law of the state in which the Company or the Affiliate is incorporated, as the case may be.

    (c) Investment Assurances. The Company may require a Participant, as a condition of exercising or acquiring Common Stock under any Stock Award, (i) to give written assurances satisfactory to the Company as to the Participant's knowledge and experience in financial and business matters and/or to employ a purchaser representative reasonably satisfactory to the Company who is knowledgeable and experienced in financial and business matters and that he or she is capable of evaluating, alone or together with the purchaser representative, the merits and risks of exercising the Stock Award; and (ii) to give written assurances satisfactory to the Company stating that the Participant is acquiring Common Stock subject to the Stock Award for the Participant's own account and not with any present intention of selling or otherwise distributing the Common Stock. The foregoing requirements, and any assurances given pursuant to such requirements, shall be inoperative if (1) the issuance of the shares of Common Stock upon the exercise or acquisition of Common Stock under the Stock Award has been registered under a then currently effective registration statement under the Securities Act or (2) as to any particular requirement, a determination is made by counsel for the Company that such requirement need not be met in the circumstances under the then applicable securities laws. The Company may, upon advice of counsel to the Company, place legends on stock certificates issued under the Plan as such counsel deems necessary or appropriate in order to comply with applicable securities laws, including, but not limited to, legends restricting the transfer of the Common Stock.

    (d) Withholding Obligations. To the extent provided by the terms of a Stock Award Agreement, the Participant may satisfy any federal, state or local tax withholding obligation relating to the exercise or acquisition of Common Stock under a Stock Award by any of the following means (in addition to the Company's right to withhold from any compensation paid to the Participant by the Company) or by a combination of such means: (i) tendering a cash payment; (ii) authorizing the Company to withhold shares of Common Stock from the shares of Common Stock otherwise issuable to the Participant as a result of the exercise or acquisition of Common Stock under the Stock Award, provided, however, that no shares of Common Stock are withheld with a value exceeding the minimum amount of tax required to be withheld by law; or (iii) delivering to the Company owned and unencumbered shares of Common Stock.

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11. ADJUSTMENTS UPON CHANGES IN STOCK.

    (a) Capitalization Adjustments. If any change is made in the Common Stock subject to the Plan, or subject to any Stock Award, without the receipt of consideration by the Company (through merger, consolidation, reorganization, recapitalization, reincorporation, stock dividend, dividend in property other than cash, stock split, liquidating dividend, combination of shares, exchange of shares, change in corporate structure or other transaction not involving the receipt of consideration by the Company), the Plan will be appropriately adjusted in the type, class(es) and maximum number of securities subject to the Plan pursuant to Section 4(a), and the outstanding Stock Awards will be appropriately adjusted in the type, class(es) and number of securities and price per share of securities subject to such outstanding Stock Awards. The Board shall make such adjustments, and its determination shall be final, binding and conclusive. (The conversion of any convertible securities of the Company shall not be treated as a transaction "without receipt of consideration" by the Company.)

    (b) Dissolution or Liquidation. In the event of a dissolution or liquidation of the Company, then all outstanding Stock Awards shall terminate immediately prior to such event.

    (c) Asset Sale, Merger, Consolidation or Reverse Merger. In the event of (i) a sale, exchange, lease or other disposition of all or substantially all of the assets of the Company, (ii) a merger or consolidation in which the Company is not the surviving corporation or (iii) a reverse merger in which the Company is the surviving corporation but the shares of Common Stock outstanding immediately preceding the merger are converted by virtue of the merger into other property, whether in the form of securities, cash or otherwise (individually, a "Corporate Transaction"), then any surviving corporation or acquiring corporation shall assume or continue any Stock Awards outstanding under the Plan or shall substitute similar stock awards (including an award to acquire the same consideration paid to the stockholders in the Corporate Transaction) for those outstanding under the Plan. In the event any surviving corporation or acquiring corporation refuses to assume or continue such Stock Awards or to substitute similar stock awards for those outstanding under the Plan, then with respect to Stock Awards held by Participants whose Continuous Service has not terminated, the vesting of such Stock Awards (and, if applicable, the time during which such Stock Awards may be exercised) shall be accelerated in full, and the Stock Awards shall terminate if not exercised (if applicable) at or prior to the Corporate Transaction. With respect to any other Stock Awards outstanding under the Plan, such Stock Awards shall terminate if not exercised (if applicable) prior to the Corporate Transaction.

12. AMENDMENT OF THE PLAN AND STOCK AWARDS.

    (a) Amendment of Plan. The Board at any time, and from time to time, may amend the Plan. However, except as provided in Section 11 relating to adjustments upon changes in stock, no amendment shall be effective unless approved by the stockholders of the Company to the extent stockholder approval is necessary for the Plan to satisfy any Nasdaq or securities exchange listing requirements. The Board may in its sole discretion submit such amendment to the Plan for stockholder approval.

    (b) No Impairment of Rights. Rights under any Stock Award granted before amendment of the Plan shall not be materially impaired by any amendment of the Plan unless (i) the Company requests the consent of the Participant and (ii) the Participant consents in writing.

    (c) Amendment of Stock Awards. The Board at any time, and from time to time, may amend the terms of any one or more Stock Awards; provided, however, that the rights under any Stock Award shall not be materially impaired by any such amendment unless (i) the Company requests the consent of the Participant and (ii) the Participant consents in writing.

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13. TERMINATION OR SUSPENSION OF THE PLAN.

    (a) Plan Term. The Board may suspend or terminate the Plan at any time. No Stock Awards may be granted under the Plan while the Plan is suspended or after it is terminated.

    (b) No Impairment of Rights. Suspension or termination of the Plan shall not impair rights and obligations under any Stock Award granted while the Plan is in effect except with the written consent of the Participant.

14. EFFECTIVE DATE OF PLAN.

    The Plan shall become effective immediately upon its adoption by the Board.

15. CHOICE OF LAW.

    The law of the State of California shall govern all questions concerning the construction, validity and interpretation of this Plan, without regard to such state's conflict of laws rules.

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2001 NON-OFFICER EQUITY INCENTIVE PLAN