Arena Pharmaceuticals, Inc. Amended and Restated 2021 Long-Term Incentive Plan, as amended as of February 8, 2022

(a)Successor to and Continuation of 2020 Plan. The Plan is the successor to and continuation of the 2020 Plan. As of the Effective Date: (i) no additional awards may be granted under the 2020 Plan or any other Prior Plan; (ii) the 2020 Plan’s Available Reserve, plus any Prior Plans’ Returning Shares (as such shares become available from time to time), will become available for issuance pursuant to Awards granted under this Plan (other than any Inducement Awards); and (iii) all Prior Plan Awards will remain subject to the terms of the applicable Prior Plan, except that any Prior Plans’ Returning Shares will become available for issuance pursuant to Awards granted under this Plan (other than any Inducement Awards). All Awards granted under this Plan will be subject to the terms of this Plan.

(b)Eligible Award Recipients. Subject to Section 4, Employees, Directors and Consultants are eligible to receive Awards.

(c)Available Awards. The Plan provides for the grant of the following types of Awards: (i) Incentive Stock Options; (ii) Nonstatutory Stock Options; (iii) Stock Appreciation Rights; (iv) Restricted Stock Awards; (v) Restricted Stock Unit Awards; (vi) Performance Stock Awards; and (vii) Other Stock Awards.

(d)Purpose. The Plan, through the granting of Awards, is intended to help the Company and any Affiliate secure and retain the services of eligible award recipients, provide incentives for such persons to exert maximum efforts for the success of the Company and any Affiliate, and provide a means by which such persons may benefit from increases in value of the Common Stock.

(a)Administration by Board. The Board will administer the Plan. The Board may delegate administration of the Plan to a Committee or Committees, as provided in Section 2(c).

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

individuals eligible to receive Awards under the Plan, (C) materially increases the benefits accruing to Participants under the Plan, (D) materially reduces the price at which shares of Common Stock may be issued or purchased under the Plan, or (E) materially expands the types of Awards available for issuance under the Plan. Except as otherwise provided in the Plan (including Section 2(b)(viii)) or an Award Agreement, no amendment of the Plan will materially impair a Participant’s rights under an outstanding Award without his or her written consent.

(viii)To approve forms of Award Agreements for use under the Plan and to amend the terms of any one or more outstanding Awards, including, but not limited to, amendments to provide terms more favorable to the Participant than previously provided in the Award Agreement, subject to any specified limits in the Plan that are not subject to Board discretion and Section 3(f)(v) with respect to Inducement Awards; provided, however, that except as otherwise provided in the Plan (including this Section 2(b)(viii)) or an Award Agreement, no amendment of an outstanding Award will materially impair a Participant’s rights under such Award without his or her written consent.

Notwithstanding the foregoing or anything in the Plan to the contrary, unless prohibited by applicable law, the Board may amend the terms of any outstanding Award or the Plan, or may suspend or terminate the Plan, without the affected Participant’s consent, (A) to maintain the qualified status of the Award as an Incentive Stock Option under Section 422 of the Code, (B) to change the terms of an Incentive Stock Option, if such change results in impairment of the Award solely because it impairs the qualified status of the Award as an Incentive Stock Option under Section 422 of the Code, (C) to clarify the manner of exemption from, or to bring the Award or the Plan into compliance with, Section 409A of the Code, or (D) to comply with other applicable laws or listing requirements.

(i)General. The Board may delegate some or all of the administration of the Plan to a Committee or Committees, subject to Section 3(f)(iii) with respect to Inducement Awards. If administration of the Plan is delegated to a Committee, the Committee will have, in connection with the administration of the Plan, the powers theretofore possessed by the Board that have been delegated to the Committee, including the power to delegate to a subcommittee of the Committee any of the administrative powers the Committee is authorized to exercise (and references in this Plan to the Board will thereafter be to the Committee or subcommittee, as applicable). Any delegation of administrative powers will be reflected in resolutions, not inconsistent with the provisions of the Plan, adopted from time to time by the Board or Committee (as applicable). The Committee may, at any time, abolish the subcommittee and/or revest in the Committee any powers delegated to the subcommittee. The Board may retain the authority to concurrently administer the Plan with the Committee and may, at any time, revest in the Board some or all of the powers previously delegated.

(ii)Rule 16b-3 Compliance. The Committee may consist solely of two or more Non-Employee Directors in accordance with Rule 16b-3.

(d)Delegation to an Officer. The Board may delegate to one or more Officers the authority to do one or both of the following, except with respect to Inducement Awards: (i) designate Employees who are not Officers to be recipients of Options and SARs (and, to the extent permitted by applicable law, other Awards) and, to the extent permitted by applicable law, the terms of such Awards; and (ii) determine the number of shares of Common Stock to be subject to such Awards granted to such Employees; provided, however, that the Board resolutions regarding such delegation will specify the total number of shares of Common Stock that may be subject to the Awards granted by such Officer and that such Officer may not grant an Award to himself or herself. Any such Awards will be granted on the form of Award Agreement most recently approved for use by the Committee or the Board, unless otherwise provided in the resolutions approving the delegation of authority. The Board may not delegate authority to an Officer who is acting solely in the capacity of an Officer (and not also as a Director) to determine the Fair Market Value of the Common Stock pursuant to Section 13(y)(iii).

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

(f)Cancellation and Re-Grant of Awards. Except as provided in Section 9(a) relating to Capitalization Adjustments, neither the Board nor any Committee will have the authority to (i) reduce the exercise or

strike price of any outstanding Option or SAR or (ii) cancel any outstanding Option or SAR that has an exercise or strike price (per share) greater than the then-current Fair Market Value of the Common Stock in exchange for cash or other Awards under the Plan (other than in connection with a Transaction), unless the stockholders of the Company have approved such an action within 12 months prior to such an event.

(g)Dividends and Dividend Equivalents. Dividends or dividend equivalents may be paid or credited, as applicable, with respect to any shares of Common Stock subject to an Award, as determined by the Board and contained in the applicable Award Agreement; provided, however, that (i) no dividends or dividend equivalents may be paid with respect to any such shares before the date such shares have vested under the terms of such Award Agreement, (ii) any dividends or dividend equivalents that are credited with respect to any such shares will be subject to all of the terms and conditions applicable to such shares under the terms of such Award Agreement (including, but not limited to, any vesting conditions), and (iii) any dividends or dividend equivalents that are credited with respect to any such shares will be forfeited to the Company on the date, if any, such shares are forfeited to or repurchased by the Company due to a failure to meet any vesting conditions under the terms of such Award Agreement.

(h)Minimum Vesting Requirement. Notwithstanding anything in the Plan to the contrary, no Award may vest until at least the first anniversary of the date the Award is granted (excluding, for this purpose, any (i) Substitute Award and (ii) Award granted to a Non-Employee Director that vests on the earlier of the first anniversary of the date of grant or the Company’s next annual meeting of stockholders which is at least 50 weeks after the immediately preceding year’s annual meeting); provided, however, that shares of Common Stock up to 5% of the Share Reserve (as defined in Section 3(a)(i) and subject to adjustment under Section 9(a)) may be issued pursuant to Awards (other than Inducement Awards) and shares of Common Stock up to 5% of the Inducement Share Reserve (as defined in Section 3(f) and subject to adjustment under Section 9(a)) may be issued pursuant to Inducement Awards, in each case that do not meet such vesting requirement; and provided further that, for the avoidance of doubt, the foregoing restriction does not apply to the Board’s discretion to provide for accelerated exercisability or vesting of any Award, including in cases of retirement, death, disability or a Transaction, in the terms of the applicable Award Agreement or otherwise.

(i)Subject to Section 9(a) relating to Capitalization Adjustments, the aggregate number of shares of Common Stock that may be issued pursuant to Awards (other than Inducement Awards) from and after the Effective Date will not exceed the sum of (A) 1,466,561 new shares, (B) the 2020 Plan’s Available Reserve, and (C) the Prior Plans’ Returning Shares, if any, as such shares become available for issuance under this Plan from time to time (such aggregate number of shares described in (A), (B) and (C), the “Share Reserve”).

(i)No Reduction to Share Reserve. The Share Reserve (and the Inducement Share Reserve, with respect to any Inducement Awards) will not be reduced by any of the following shares of Common Stock and such shares will remain available for issuance under the Plan: (A) any shares subject to an Award that are not issued because such Award or any portion thereof expires or otherwise terminates without all of the shares covered by such Award having been issued; and (B) any shares subject to an Award that are not issued because such Award or any portion thereof is settled in cash.

(1)Shares Available for Subsequent Issuance. If any shares of Common Stock issued pursuant to an Award are forfeited back to or repurchased by the Company because of the failure to meet a contingency or condition required for the vesting of such shares, then such shares will revert to the Share Reserve (or the Inducement Share Reserve, with respect to any Inducement Awards) and become again available for issuance under the Plan.

(2)Shares Not Available for Subsequent Issuance. The following shares of Common Stock will not revert to the Share Reserve (or the Inducement Share Reserve, with respect to any Inducement Awards) or become available again for issuance under the Plan: (A) any shares that are reacquired or withheld (or not issued) by the Company to satisfy the exercise, strike or purchase price of an Award or a Prior Plan Award (including any shares subject to such award that are not delivered because such award is exercised through a reduction of shares subject to such award (i.e., “net exercised”)); (B) any shares that are reacquired or withheld (or

not issued) by the Company to satisfy a tax withholding obligation in connection with an Award or a Prior Plan Award; (C) any shares repurchased by the Company on the open market with the proceeds of the exercise, strike or purchase price of an Award or a Prior Plan Award; and (D) in the event that a Stock Appreciation Right granted under the Plan or a stock appreciation right granted under any of the Prior Plans is settled in shares of Common Stock, the gross number of shares of Common Stock subject to such award.

(c)Incentive Stock Option Limit. Subject to the Share Reserve and Section 9(a) relating to Capitalization Adjustments, the aggregate maximum number of shares of Common Stock that may be issued pursuant to the exercise of Incentive Stock Options will be 2,250,000 shares.

(d)Non-Employee Director Compensation Limit. The aggregate value of all cash and equity-based compensation (including Awards and any other equity-based awards) paid or granted, as applicable, by the Company to any individual for service as a Non-Employee Director with respect to any period commencing on the date of the Company’s annual meeting of stockholders for a particular year and ending on the day immediately prior to the date of the Company’s annual meeting of stockholders for the next subsequent year will not exceed (i) $750,000 in total value for any Non-Employee Director who is not in a lead director or chairman role or (ii) $1,000,000 in total value for any Non-Employee Director who is (x) in a lead director or chairman role or (y) first appointed or elected to the Board during such period, in each case calculating the value of any equity-based awards based on the grant date fair value of such awards for financial reporting purposes.

(e)Source of Shares. The stock issuable under the Plan will be shares of authorized but unissued or reacquired Common Stock, including shares repurchased by the Company on the open market or otherwise.

(f)Inducement Awards. Subject to Section 9(a) relating to Capitalization Adjustments, an additional 573,879 shares of Common Stock are reserved under the Plan exclusively for the grant of Inducement Awards in compliance with the Inducement Award Rules (the “Inducement Shares” and such reserved number of shares, the “Inducement Share Reserve”). The Inducement Shares that may be awarded under this Section 3(f) will be in addition to and will not reduce the shares of Common Stock available for issuance under Section 3(a). The following rules and restrictions will apply to each Inducement Award, notwithstanding anything in the Plan to the contrary:

(a)Eligibility for Specific Awards. Incentive Stock Options may be granted only to employees of the Company or a “parent corporation” or “subsidiary corporation” thereof (as such terms are defined in Sections 424(e) and 424(f) of the Code); provided, however, that Incentive Stock Options may not be granted as Inducement Awards. Awards other than Incentive Stock Options may be granted to Employees, Directors and Consultants; provided, however, that Awards may not be granted to Employees, Directors and Consultants who are providing Continuous Service only to any “parent” of the Company, as such term is defined in Rule 405, unless (i) the stock underlying such Awards is treated as “service recipient stock” under Section 409A of the Code (for example, because the Awards are granted pursuant to a corporate transaction such as a spin off transaction) or (ii) the Company, in consultation with its legal counsel, has determined that such Awards are otherwise exempt from or alternatively comply with Section 409A of the Code.

(b)Ten Percent Stockholders. A Ten Percent Stockholder will not be granted an Incentive Stock Option unless the exercise price (per share) of such Option is at least 110% of the Fair Market Value of the Common Stock on the date of grant of such Option and the Option is not exercisable after the expiration of five years from the date of grant.

Each Option or SAR Agreement will be in such form and will contain such terms and conditions as the Board deems appropriate. All Options will be separately designated Incentive Stock Options or Nonstatutory Stock Options at the time of grant, and, if certificates are issued, a separate certificate or certificates will be issued for shares of Common Stock purchased on exercise of each type of Option. If an Option is not specifically designated as an Incentive Stock Option, or if an Option is designated as an Incentive Stock Option but some portion or all of the Option fails to qualify as an Incentive Stock Option under the applicable rules, then the Option (or portion thereof) will be a Nonstatutory Stock Option. The terms and conditions of separate Option or SAR Agreements need not be identical; provided, however, that each Award Agreement will conform to (through incorporation of the provisions hereof by reference in the applicable Award Agreement or otherwise) the substance of each of the following provisions:

(a)Term. Subject to the provisions of Section 4(b) regarding Ten Percent Stockholders, no Option or SAR will be exercisable after the expiration of seven years from the date of its grant or such shorter period specified in the Award Agreement.

(b)Exercise or Strike Price. Subject to the provisions of Section 4(b) regarding Ten Percent Stockholders, the exercise or strike price (per share) of each Option or SAR will be not less than 100% of the Fair Market Value of the Common Stock on the date the Award is granted. Notwithstanding the foregoing, an Option or SAR may be granted with an exercise or strike price (per share) less than 100% of the Fair Market Value of the Common Stock on the date the Award is granted if such Award is granted pursuant to an assumption of, or substitution for, another option or stock appreciation right pursuant to a Transaction and in a manner consistent with the provisions of Section 409A of the Code and, if applicable, Section 424(a) of the Code. Each SAR will be denominated in shares of Common Stock equivalents.

(c)Payment of Exercise Price for Options. The exercise price of an Option may be paid, to the extent permitted by applicable law and as determined by the Board in its sole discretion, by one or more of the methods of payment set forth below that are specified in the Option Agreement. The Board has the authority to grant Options that do not permit all of the following methods of payment (or that otherwise restrict the ability to utilize certain methods) and to grant Options that require the consent of the Company to utilize a particular method of payment.

(iv)If an Option is a Nonstatutory Stock Option, by a “net exercise” arrangement pursuant to which the Company will reduce the number of shares of Common Stock issuable upon exercise by the largest whole number of shares with a Fair Market Value that does not exceed the aggregate exercise price; provided, however, that the Company will accept a cash or other payment from the Participant to the extent of any remaining balance of the aggregate exercise price not satisfied by such reduction in the number of whole shares to be issued. Shares of Common Stock will no longer be subject to an Option and will not be exercisable thereafter to the extent that (A) shares issuable upon exercise are used to pay the exercise price pursuant to the “net exercise,” (B) shares are delivered to the Participant as a result of such exercise, and (C) shares are withheld to satisfy tax withholding obligations; or

(d)Exercise and Payment of a SAR. To exercise any outstanding SAR, the Participant must provide written notice of exercise to the Company in compliance with the provisions of the Award Agreement evidencing such SAR. The appreciation distribution payable on the exercise of a SAR will be not greater than an amount equal to the excess of (A) the aggregate Fair Market Value (on the date of the exercise of the SAR) of a number of shares of Common Stock equal to the number of Common Stock equivalents in which the Participant is vested under such SAR, and with respect to which the Participant is exercising the SAR on such date, over (B) the aggregate strike price of the number of Common Stock equivalents with respect to which the Participant is exercising the SAR on such date. The appreciation distribution may be paid in Common Stock, in cash, in any combination of the two or in any other form of consideration, as determined by the Board and contained in the Award Agreement evidencing such SAR.

(e)Transferability of Options and SARs. The Board may, in its sole discretion, impose such limitations on the transferability of Options and SARs as the Board will determine. In the absence of such a determination by the Board to the contrary, the restrictions set forth in this Section 5(e) on the transferability of Options and SARs will apply. Notwithstanding the foregoing or anything in the Plan or an Award Agreement to the contrary, no Option or SAR may be transferred to any financial institution without prior stockholder approval.

(i)Restrictions on Transfer. An Option or SAR will not be transferable, except by will or by the laws of descent and distribution (and pursuant to Sections 5(e)(ii) and 5(e)(iii) below) and will be exercisable during the lifetime of the Participant only by the Participant. Subject to the foregoing paragraph, the Board may, in its sole discretion, permit transfer of the Option or SAR in a manner that is not prohibited by applicable tax and securities laws. Except as explicitly provided in the Plan, neither an Option nor a SAR may be transferred for consideration.

(ii)Domestic Relations Orders. Subject to the approval of the Board or a duly authorized Officer, an Option or SAR may be transferred pursuant to the terms of a domestic relations order, official marital settlement agreement or other divorce or separation instrument as permitted by Treasury Regulations Section 1.421-1(b)(2). If an Option is an Incentive Stock Option, such Option may be deemed to be a Nonstatutory Stock Option as a result of such transfer.

(iii)Beneficiary Designation. Subject to the approval of the Board or a duly authorized Officer, a Participant may, by delivering written notice to the Company, in a form approved by the Company (or the designated broker), designate a third party who, upon the death of the Participant, will thereafter be entitled to exercise the Option or SAR and receive the Common Stock or other consideration resulting from such exercise. In the absence of such a designation, upon the death of the Participant, the executor or administrator of the Participant’s estate will be entitled to exercise the Option or SAR and receive the Common Stock or other consideration resulting from such exercise. However, the Company may prohibit designation of a beneficiary at any time, including due to any conclusion by the Company that such designation would be inconsistent with the provisions of applicable laws.

(f)Vesting. The total number of shares of Common Stock subject to an Option or SAR may vest and become exercisable in periodic installments that may or may not be equal. The Option or SAR may be subject to such other terms and conditions on the time or times when it may or may not be exercised (which may be based on the satisfaction of Performance Goals or other criteria) as the Board may deem appropriate. The vesting provisions of individual Options or SARs may vary. The provisions of this Section 5(f) are subject to Section 2(h) and any Option or SAR provisions governing the minimum number of shares of Common Stock as to which an Option or SAR may be exercised.

(g)Termination of Continuous Service. Except as otherwise provided in the applicable Award Agreement or other written agreement between a Participant and the Company or an Affiliate, if a Participant’s Continuous Service terminates (other than for Cause and other than upon the Participant’s death or Disability), the Participant may exercise his or her Option or SAR (to the extent that the Participant was entitled to exercise such Option or SAR as of the date of termination of Continuous Service), but only within such period of time ending on the earlier of (i) the date that is 90 days following such termination of Continuous Service (or such longer or shorter period specified in the Award Agreement), and (ii) the expiration of the term of the Option or SAR as set forth in the Award Agreement. If, after such termination of Continuous Service, the Participant does not exercise his or her Option or SAR (as applicable) within the applicable time period, the Option or SAR (as applicable) will terminate.

(h)Extension of Termination Date. Except as otherwise provided in the applicable Award Agreement or other written agreement between a Participant and the Company or an Affiliate, if the exercise of an Option or SAR following the termination of a Participant’s Continuous Service (other than for Cause and other than upon the Participant’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, then the Option or SAR will terminate on the earlier of (i) the expiration of a total period of time (that need not be consecutive) equal to the applicable post-termination exercise period after the termination of the Participant’s Continuous Service during which the exercise of the Option or SAR would not be in violation of such registration requirements or (ii) the expiration of the term of the Option or SAR as set forth in the applicable Award Agreement. In addition, except as otherwise provided in the applicable Award Agreement or other written agreement between a Participant and the Company or an Affiliate, if the sale of any Common Stock received upon exercise of an Option or SAR following the termination of a Participant’s Continuous Service (other than for Cause) would violate the Company’s insider trading policy, then the Option or SAR will terminate on the earlier of (i) the expiration of a total period of time (that need not be consecutive) equal to the applicable post-termination exercise period after the termination of the Participant’s Continuous Service during which the sale of the Common Stock received upon exercise of the Option or SAR would not be in violation of the Company’s insider trading policy or (ii) the expiration of the term of the Option or SAR as set forth in the applicable Award Agreement.

(i)Disability of Participant. Except as otherwise provided in the applicable Award Agreement or other written agreement between a Participant and the Company or an Affiliate, if a Participant’s Continuous Service terminates as a result of the Participant’s Disability, the Participant may exercise his or her Option or SAR (to the extent that the Participant was entitled to exercise such Option or SAR as of the date of termination of Continuous Service), but only within such period of time ending on the earlier of (i) the date that is 12 months following such termination of Continuous Service (or such longer or shorter period specified in the Award Agreement), and (ii) the

expiration of the term of the Option or SAR as set forth in the Award Agreement. If, after such termination of Continuous Service, the Participant does not exercise his or her Option or SAR (as applicable) within the applicable time period, the Option or SAR (as applicable) will terminate.

(j)Death of Participant. Except as otherwise provided in the applicable Award Agreement or other written agreement between a Participant and the Company or an Affiliate, if (i) a Participant’s Continuous Service terminates as a result of the Participant’s death, or (ii) a Participant dies within the period (if any) specified in the Award Agreement for exercisability after the termination of the Participant’s Continuous Service (for a reason other than death), then the Participant’s Option or SAR may be exercised (to the extent that the Participant was entitled to exercise such Option or SAR as of the date of death) by the Participant’s estate, by a person who acquired the right to exercise the Option or SAR by bequest or inheritance, or by a person designated to exercise the Option or SAR upon the Participant’s death, but only within such period of time ending on the earlier of (i) the date that is 12 months following the date of death (or such longer or shorter period specified in the Award Agreement), and (ii) the expiration of the term of the Option or SAR as set forth in the Award Agreement. If, after the Participant’s death, the Option or SAR (as applicable) is not exercised within the applicable time period, the Option or SAR (as applicable) will terminate.

(k)Termination for Cause. Except as explicitly provided otherwise in the applicable Award Agreement or other individual written agreement between a Participant and the Company or an Affiliate, if a Participant’s Continuous Service is terminated for Cause, the Participant’s Option or SAR will terminate immediately upon such termination of Continuous Service, and the Participant will be prohibited from exercising his or her Option or SAR from and after the time of such termination of Continuous Service.

(l)Non-Exempt Employees. If an Option or SAR is granted to an Employee who is a non-exempt employee for purposes of the Fair Labor Standards Act of 1938, as amended, the Option or SAR will not be first exercisable for any shares of Common Stock until at least six months following the date of grant of the Option or SAR (although the Award may vest prior to such date). Consistent with the provisions of the Worker Economic Opportunity Act, (i) if such non-exempt employee dies or suffers a Disability, (ii) upon a Transaction in which such Option or SAR is not assumed, continued or substituted, (iii) upon a Change in Control, or (iv) upon the Participant’s retirement (as such term may be defined in the Participant’s Award Agreement, in another written agreement between the Participant and the Company or an Affiliate, or, if no such definition, in accordance with the Company’s or Affiliate’s then current employment policies and guidelines), the vested portion of any Options and SARs may be exercised earlier than six months following the date of grant. The foregoing provision is intended to operate so that any income derived by a non-exempt employee in connection with the exercise or vesting of an Option or SAR will be exempt from his or her regular rate of pay. To the extent permitted and/or required for compliance with the Worker Economic Opportunity Act to ensure that any income derived by a non-exempt employee in connection with the exercise, vesting or issuance of any shares under any other Award will be exempt from the employee’s regular rate of pay, the provisions of this Section 5(l) will apply to all Awards and are hereby incorporated by reference into such Award Agreements.

(a)Restricted Stock Awards. Each Restricted Stock Award Agreement will be in such form and will contain such terms and conditions as the Board deems appropriate. To the extent consistent with the Company’s bylaws, at the Board’s election, shares of Common Stock underlying a Restricted Stock Award may be (i) held in book entry form subject to the Company’s instructions until any restrictions relating to the Restricted Stock Award lapse, or (ii) evidenced by a certificate, which certificate will be held in such form and manner as determined by the Board. The terms and conditions of separate Restricted Stock Award Agreements need not be identical; provided, however, that each Restricted Stock Award Agreement will conform to (through incorporation of the provisions hereof by reference in the applicable Award Agreement or otherwise) the substance of each of the following provisions:

(i)Consideration. A Restricted Stock Award may be awarded in consideration for (A) cash (including electronic funds transfers), check, bank draft or money order payable to the Company, (B) past services to the Company or an Affiliate (other than with respect to any Inducement Awards) or (C) any other form of legal consideration (including future services) that may be acceptable to the Board, in its sole discretion, and permissible under applicable law.

(ii)Vesting. Subject to Section 2(h), shares of Common Stock awarded under a Restricted Stock Award Agreement may be subject to forfeiture to or repurchase by the Company in accordance with a vesting schedule to be determined by the Board.

(iii)Termination of Continuous Service. If a Participant’s Continuous Service terminates, the Company may receive through a forfeiture condition or a repurchase right any or all of the shares of Common Stock held by the Participant that have not vested as of the date of such termination under the terms of the Participant’s Restricted Stock Award Agreement.

(iv)Transferability. Rights to acquire shares of Common Stock under a Restricted Stock Award Agreement will be transferable by the Participant only upon such terms and conditions as are set forth in the Restricted Stock Award Agreement, as the Board will determine in its sole discretion, so long as Common Stock

awarded under the Restricted Stock Award Agreement remains subject to the terms of the Restricted Stock Award Agreement. Notwithstanding the foregoing or anything in the Plan or a Restricted Stock Award Agreement to the contrary, no Restricted Stock Award may be transferred to any financial institution without prior stockholder approval.

(b)Restricted Stock Unit Awards. Each Restricted Stock Unit Award Agreement will be in such form and will contain such terms and conditions as the Board deems appropriate. The terms and conditions of separate Restricted Stock Unit Award Agreements need not be identical; provided, however, that each Restricted Stock Unit Award Agreement will conform to (through incorporation of the provisions hereof by reference in the applicable Award Agreement or otherwise) the substance of each of the following provisions:

(i)Consideration. At the time of grant of a Restricted Stock Unit Award, the Board will determine the consideration, if any, to be paid by the Participant upon delivery of each share of Common Stock subject to the Restricted Stock Unit Award. The consideration to be paid (if any) by the Participant for each share of Common Stock subject to a Restricted Stock Unit Award may be paid in any form of legal consideration that may be acceptable to the Board, in its sole discretion, and permissible under applicable law.

(ii)Vesting. Subject to Section 2(h), at the time of the grant of a Restricted Stock Unit Award, the Board may impose such restrictions on or conditions to the vesting of the Restricted Stock Unit Award as it, in its sole discretion, deems appropriate.

(iii)Payment. A Restricted Stock Unit Award may be settled by the delivery of shares of Common Stock, their cash equivalent, any combination thereof or in any other form of consideration, as determined by the Board and contained in the Restricted Stock Unit Award Agreement.

(iv)Additional Restrictions. At the time of the grant of a Restricted Stock Unit Award, the Board, as it deems appropriate, may impose such restrictions or conditions that delay the delivery of the shares of Common Stock (or their cash equivalent) subject to the Restricted Stock Unit Award to a time after the vesting of the Restricted Stock Unit Award.

(v)Termination of Continuous Service. Except as otherwise provided in the applicable Restricted Stock Unit Award Agreement or other written agreement between a Participant and the Company or an Affiliate, if a Participant’s Continuous Service terminates, any portion of the Participant’s Restricted Stock Unit Award that has not vested as of the date of such termination will be forfeited upon such termination.

(i)General. A Performance Stock Award is an Award that is payable (including that may be granted, vest or be exercised) contingent upon the attainment during a Performance Period of specified Performance Goals. A Performance Stock Award may, but need not, require the Participant’s completion of a specified period of Continuous Service. Subject to Section 2(h), the length of any Performance Period, the Performance Goals to be achieved during the Performance Period, and the measure of whether and to what degree such Performance Goals have been attained will be conclusively determined by the Board, in its sole discretion. In addition, to the extent permitted by applicable law and the applicable Award Agreement, the Board may determine that cash may be used in payment of Performance Stock Awards.

(ii)Board Discretion. With respect to any Performance Stock Award, the Board retains the discretion to (A) reduce or eliminate the compensation or economic benefit due upon the attainment of any Performance Goals on the basis of any considerations as the Board, in its sole discretion, may determine and (B) define the manner of calculating the Performance Criteria it selects to use for a Performance Period.

(d)Other Stock Awards. Other forms of Awards valued in whole or in part by reference to, or otherwise based on, Common Stock, including the appreciation in value thereof may be granted either alone or in addition to Awards granted under Section 5 and this Section 6. Subject to the provisions of the Plan (including, but not limited to, Sections 2(g) and 2(h)), the Board will have sole and complete authority to determine the persons to whom and the time or times at which such Other Stock Awards will be granted, the number of shares of Common Stock (or the cash equivalent thereof) to be granted pursuant to such Other Stock Awards, and all other terms and conditions of such Other Stock Awards.

(a)Availability of Shares. The Company will keep available at all times the number of shares of Common Stock reasonably required to satisfy then-outstanding Awards.

(b)Securities Law Compliance. The Company will seek to obtain from each regulatory commission or agency having jurisdiction over the Plan the authority required to grant Awards and to issue and sell shares of Common Stock upon exercise of the Awards; provided, however, that this undertaking will not require the Company to register under the Securities Act the Plan, any Award or any Common Stock issued or issuable pursuant to any such

Award. If, after reasonable efforts and at a reasonable cost, the Company is unable to obtain from any such regulatory commission or agency the authority that counsel for the Company deems necessary for the lawful issuance and sale of Common Stock under the Plan, the Company will be relieved from any liability for failure to issue and sell Common Stock upon exercise of such Awards unless and until such authority is obtained. A Participant will not be eligible for the grant of an Award or the subsequent issuance of cash or Common Stock pursuant to the Award if such grant or issuance would be in violation of any applicable securities law.

(c)No Obligation to Notify or Minimize Taxes. The Company will have no duty or obligation to any Participant to advise such holder as to the time or manner of exercising an Award. Furthermore, the Company will have no duty or obligation to warn or otherwise advise such holder of a pending termination or expiration of an Award or a possible period in which the Award may not be exercised. The Company has no duty or obligation to minimize the tax consequences of an Award to the holder of such Award.

(a)Use of Proceeds from Sales of Common Stock. Proceeds from the sale of shares of Common Stock issued pursuant to Awards will constitute general funds of the Company.

(b)Corporate Action Constituting Grant of Awards. Corporate action constituting a grant by the Company of an Award to any Participant will be deemed completed as of the date of such corporate action, unless otherwise determined by the Board, regardless of when the instrument, certificate or letter evidencing the Award is communicated to, or actually received or accepted by, the Participant. In the event that the corporate records (e.g., Board consents, resolutions or minutes) documenting the corporate action constituting the grant contain terms (e.g., exercise price, vesting schedule or number of shares) that are inconsistent with those in the Award Agreement or related grant documents as a result of a clerical error in the papering of the Award Agreement or related grant documents, the corporate records will control and the Participant will have no legally binding right to the incorrect term in the Award Agreement or related grant documents.

(c)Stockholder Rights. No Participant will 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 an Award unless and until (i) such Participant has satisfied all requirements for exercise of, or the issuance of shares of Common Stock under, the Award pursuant to its terms, and (ii) the issuance of the Common Stock subject to such Award has been entered into the books and records of the Company.

(d)No Employment or Other Service Rights. Nothing in the Plan, any Award Agreement or any other instrument executed thereunder or in connection with any Award granted pursuant thereto will confer upon any Participant any right to continue to serve the Company or an Affiliate in the capacity in effect at the time the Award was granted or will 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 Director pursuant to the bylaws of the Company or an Affiliate, or (iii) the service of a Consultant pursuant to the terms of such Consultant’s agreement with 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.

(e)Change in Time Commitment. In the event a Participant’s regular level of time commitment in the performance of his or her services for the Company or any Affiliate is reduced (for example, and without limitation, if the Participant is an Employee of the Company and the Employee has a change in status from a full-time Employee to a part-time Employee or takes an extended leave of absence) after the date of grant of any Award to the Participant, the Board has the right in its sole discretion to (i) make a corresponding reduction in the number of shares or cash amount subject to any portion of such Award that is scheduled to vest or become payable after the date of such change in time commitment, and (ii) in lieu of or in combination with such a reduction, extend the vesting or payment schedule applicable to such Award. In the event of any such reduction, the Participant will have no right with respect to any portion of the Award that is so reduced or extended.

(f)Incentive Stock Option Limitation. To the extent that the aggregate Fair Market Value (determined at the time of grant) of Common Stock with respect to which Incentive Stock Options are exercisable for the first time by any Participant during any calendar year (under all plans of the Company and any Affiliates) exceeds $100,000 (or such other limit established in the Code) or otherwise does not comply with the rules governing Incentive Stock Options, the Options or portions thereof that exceed such limit (according to the order in which they were granted) or otherwise do not comply with such rules will be treated as Nonstatutory Stock Options, notwithstanding any contrary provision of the applicable Option Agreement(s).

(g)Investment Assurances. The Company may require a Participant, as a condition of exercising or acquiring Common Stock under any 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 Award and (ii) to give written assurances satisfactory to the Company stating that the Participant is acquiring Common Stock subject to the 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, will be inoperative if (A) the issuance of the shares upon the exercise or acquisition of Common Stock under the Award has been registered under a then currently effective registration statement under the Securities Act or (B) 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.

(h)Withholding Obligations. Unless prohibited by the terms of an Award Agreement, the Company may, in its sole discretion, satisfy any federal, state, local or foreign tax withholding obligation relating to an Award by any of the following means or by a combination of such means: (i) causing the Participant to tender a cash payment; (ii)  withholding shares of Common Stock from the shares of Common Stock issued or otherwise issuable to the Participant in connection with the Award; (iii) withholding cash from an Award settled in cash; (iv) withholding payment from any amounts otherwise payable to the Participant; or (v) by such other method as may be set forth in the Award Agreement.

(i)Electronic Delivery. Any reference herein to a “written” agreement or document will include any agreement or document delivered electronically, filed publicly at www.sec.gov (or any successor website thereto) or posted on the Company’s intranet (or other shared electronic medium controlled by the Company to which the Participant has access).

(j)Deferrals. To the extent permitted by applicable law, the Board, in its sole discretion, may determine that the delivery of Common Stock or the payment of cash, upon the exercise, vesting or settlement of all or a portion of any Award may be deferred and may establish programs and procedures for deferral elections to be made by Participants. Deferrals by Participants will be made in accordance with Section 409A of the Code. Consistent with Section 409A of the Code, the Board may provide for distributions while a Participant is still an employee or otherwise providing services to the Company or an Affiliate. The Board is authorized to make deferrals of Awards and determine when, and in what annual percentages, Participants may receive payments, including lump sum payments, following the Participant’s termination of Continuous Service, and implement such other terms and conditions consistent with the provisions of the Plan and in accordance with applicable law.

(k)Section 409A. Unless otherwise expressly provided for in an Award Agreement, the Plan and Award Agreements will be interpreted to the greatest extent possible in a manner that makes the Plan and the Awards granted hereunder exempt from Section 409A of the Code, and, to the extent not so exempt, in compliance with Section 409A of the Code. If the Board determines that any Award granted hereunder is not exempt from and is therefore subject to Section 409A of the Code, the Award Agreement evidencing such Award will incorporate the terms and conditions necessary to avoid the consequences specified in Section 409A(a)(1) of the Code, and to the extent an Award Agreement is silent on terms necessary for compliance with Section 409A of the Code, such terms are hereby incorporated by reference into the Award Agreement. Notwithstanding anything to the contrary in this Plan (and unless the Award Agreement specifically provides otherwise), if the shares of Common Stock are publicly traded, and if a Participant holding an Award that constitutes “deferred compensation” under Section 409A of the Code is a “specified employee” for purposes of Section 409A of the Code, no distribution or payment of any amount under such Award that is due because of a “separation from service” (as defined in Section 409A of the Code without regard to alternative definitions thereunder) will be issued or paid before the date that is six months and one day following the date of such Participant’s “separation from service” or, if earlier, the date of the Participant’s death, unless such distribution or payment may be made in a manner that complies with Section 409A of the Code, and any amounts so deferred will be paid in a lump sum on the day after such six-month period elapses, with the balance paid thereafter on the original schedule.

(l)Clawback/Recovery. All Awards granted under the Plan will be subject to recoupment in accordance with any clawback policy that the Company is required to adopt pursuant to the listing standards of any national securities exchange or association on which the Company’s securities are listed or as is otherwise required by the Dodd-Frank Wall Street Reform and Consumer Protection Act or other applicable law, and any other clawback policy that the Company adopts. In addition, the Board may impose such other clawback, recovery or recoupment provisions in an Award Agreement as the Board determines necessary or appropriate, including, but not limited to, a reacquisition right in respect of previously acquired shares of Common Stock or other cash or property upon the occurrence of Cause. No recovery of compensation under such a clawback policy will be an event giving rise to a right to resign for “good reason” or “constructive termination” (or similar term) under any agreement with the Company or an Affiliate.

(m)Forfeiture for Cause. Notwithstanding anything in the Plan or an Award Agreement to the contrary, in addition to the provisions set forth in Section 5(k) of the Plan with respect to Options and SARs, if the Board determines that a Participant has engaged in conduct during the Participant’s Continuous Service that constitutes Cause, then immediately upon such determination and regardless of whether the Participant’s Continuous Service is terminated for Cause at such time, (i) each of the Participant’s Awards, to the extent outstanding and unvested as of the date of such determination, will terminate, and (ii) the Participant will forfeit any shares subject to such Awards that are outstanding and unvested as of the date of such determination.

(a)Capitalization Adjustments. In the event of a Capitalization Adjustment, the Board will appropriately and proportionately adjust: (i) the class(es) and maximum number of securities subject to the Plan pursuant to Sections 3(a) and 3(f); (ii) the class(es) and maximum number of securities that may be issued pursuant to the exercise of Incentive Stock Options pursuant to Section 3(c); and (iii) the class(es) and number of securities and price per share of stock subject to outstanding Awards. The Board will make such adjustments and its determination will be final, binding and conclusive.

(b)Dissolution or Liquidation. Except as otherwise provided in the applicable Award Agreement or other written agreement between a Participant and the Company or an Affiliate, in the event of a dissolution or liquidation of the Company, all outstanding Awards (other than Awards consisting of vested and outstanding shares of Common Stock not subject to a forfeiture condition or the Company’s right of repurchase) will terminate immediately prior to the completion of such dissolution or liquidation, and the shares of Common Stock subject to a forfeiture condition or the Company’s right of repurchase may be reacquired or repurchased by the Company notwithstanding the fact that the holder of such Award is providing Continuous Service.

(c)Transactions. In the event of a Transaction, the provisions of this Section 9(c) will apply to each outstanding Award unless otherwise provided in the instrument evidencing the Award, in any other written agreement between a Participant and the Company or an Affiliate, or in any director compensation policy of the Company.

(i)Awards May Be Assumed. In the event of a Transaction, any surviving corporation or acquiring corporation (or the surviving or acquiring corporation’s parent company) may assume or continue any or all outstanding Awards or may substitute similar stock awards for any or all outstanding Awards (including, but not limited to, awards to acquire the same consideration paid to the stockholders of the Company pursuant to the Transaction), and any reacquisition or repurchase rights held by the Company in respect of Common Stock issued pursuant to any outstanding Awards may be assigned by the Company to the surviving corporation or acquiring corporation (or the surviving or acquiring corporation’s parent company). For clarity, in the event of a Transaction, any surviving corporation or acquiring corporation (or the surviving or acquiring corporation’s parent company) may choose to assume or continue only a portion of an outstanding Award, to substitute a similar stock award for only a portion of an outstanding Award, or to assume or continue, or substitute similar stock awards for, the outstanding Awards held by some, but not all, Participants. The terms of any such assumption, continuation or substitution will be set by the Board.

(ii)Awards Held by Current Participants. In the event of a Transaction in which the surviving corporation or acquiring corporation (or the surviving or acquiring corporation’s parent company) does not assume or continue outstanding Awards, or substitute similar stock awards for outstanding Awards, then with respect to any such Awards that have not been assumed, continued or substituted and that are held by Participants whose Continuous Service has not terminated prior to the effective time of the Transaction (referred to as the “Current Participants”), the vesting (and exercisability, if applicable) of such Awards will be accelerated in full (and with respect to any such Awards that are subject to performance-based vesting conditions or requirements, vesting will be deemed to be satisfied at the greater of (x) the target level of performance or (y) the actual level of performance measured in accordance with the applicable performance goals as of the date of the Transaction) to a date prior to the effective time of the Transaction (contingent upon the closing or completion of the Transaction) as the Board will determine (or, if the Board does not determine such a date, to the date that is five days prior to the effective time of the Transaction), and such Awards will terminate if not exercised (if applicable) prior to the effective time of the Transaction in accordance with the exercise procedures determined by the Board, and any reacquisition or repurchase rights held by the Company with respect to such Awards will lapse (contingent upon the closing or completion of the Transaction).

(iii)Awards Held by Participants other than Current Participants. In the event of a Transaction in which the surviving corporation or acquiring corporation (or the surviving or acquiring corporation’s parent company) does not assume or continue outstanding Awards, or substitute similar stock awards for outstanding Awards, then with respect to any such Awards that have not been assumed, continued or substituted and that are held by Participants other than Current Participants, such Awards will terminate if not exercised (if applicable) prior to the effective time of the Transaction in accordance with the exercise procedures determined by the Board; provided, however, that any reacquisition or repurchase rights held by the Company with respect to such Awards will not terminate and may continue to be exercised notwithstanding the Transaction.

(iv)Payment for Awards in Lieu of Exercise. Notwithstanding the foregoing, in the event any outstanding Award held by a Participant will terminate if not exercised prior to the effective time of a Transaction, the Board may provide that the Participant may not exercise such Award but instead will receive a payment, in such form as may be determined by the Board, equal in value to the excess, if any, of (A) the value of the property the Participant would have received upon the exercise of such Award immediately prior to the effective time of the Transaction, over (B) any exercise price payable by the Participant in connection with such exercise. For clarity, such payment may be zero if the value of such property is equal to or less than the exercise price. Payments under this provision may be delayed to the same extent that payment of consideration to the holders of the Common Stock in connection with the Transaction is delayed as a result of escrows, earn outs, holdbacks or any other contingencies.

(d)Change in Control. Unless provided otherwise in the Award Agreement for an Award, in any other written agreement or plan between the Company or any Affiliate and the Participant, or in any director compensation policy of the Company, an Award will not be subject to additional acceleration of vesting and exercisability upon or after a Change in Control.

(e)Parachute Payments. Except as otherwise provided in the applicable Award Agreement or other written agreement between a Participant and the Company or an Affiliate, if any payment or benefit the Participant would receive pursuant to a Change in Control from the Company or otherwise (“Payment”) would (i) constitute a “parachute payment” within the meaning of Section 280G of the Code, and (ii) but for this sentence, be subject to the excise tax imposed by Section 4999 of the Code (the “Excise Tax”), then such Payment will be equal to the Reduced Amount. The “Reduced Amount” will be either (x) the largest portion of the Payment that would result in no portion of the Payment being subject to the Excise Tax or (y) the largest portion, up to and including the total, of the Payment, whichever amount, after taking into account all applicable federal, state and local employment taxes, income taxes, and the Excise Tax (all computed at the highest applicable marginal rate), results in the Participant’s receipt, on an after-tax basis, of the greater amount of the Payment notwithstanding that all or some portion of the Payment may be subject to the Excise Tax. If a reduction in payments or benefits constituting “parachute payments” is necessary so that the Payment equals the Reduced Amount, reduction will occur in the following order: (A) reduction of cash payments; (B) cancellation of accelerated vesting of equity awards other than stock options; (C) cancellation of accelerated vesting of stock options; and (D) reduction of other benefits paid to the Participant. Within any such category of payments and benefits (that is, (A), (B), (C) or (D)), a reduction will occur first with respect to amounts that are not “deferred compensation” within the meaning of Section 409A of the Code and then with respect to amounts that are. In the event that acceleration of compensation from a Participant’s equity awards is to be reduced, such acceleration of vesting will be canceled, subject to the immediately preceding sentence, in the reverse order of the date of grant. The accounting firm engaged by the Company for general audit purposes as of the day prior to the effective date of the Change in Control will perform the foregoing calculations. If the accounting firm so engaged by the Company is serving as accountant or auditor for the individual, entity or group effecting the Change in Control, the Company will appoint a nationally recognized accounting firm to make the determinations required hereunder. The Company will bear all expenses with respect to the determinations by such accounting firm required to be made hereunder. The accounting firm engaged to make the determinations hereunder will provide its calculations, together with detailed supporting documentation, to the Participant and the Company within 15 calendar days after the date on which the Participant’s right to a Payment is triggered (if requested at that time by the Participant or the Company) or such other time as reasonably requested by the Participant or the Company. Any good faith determinations of the accounting firm made hereunder will be final, binding and conclusive upon the Participant and the Company.

(a)Termination or Suspension. The Board may suspend or terminate the Plan at any time. No Incentive Stock Option may be granted after the tenth anniversary of the earlier of (i) the Adoption Date or (ii) the date the Plan is approved by the stockholders of the Company. No 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 will not materially impair rights and obligations under any Award granted while the Plan is in effect except with the written consent of the affected Participant or as otherwise permitted in the Plan (including Section 2(b)(viii)) or an Award Agreement.

The laws of the State of Delaware will govern all questions concerning the construction, validity and interpretation of this Plan, without regard to that state’s conflict of laws rules.

13.Definitions. As used in the Plan, the following definitions will apply to the capitalized terms indicated below:

(a)“2020 Plan” means the Arena Pharmaceuticals, Inc. Amended and Restated 2020 Long-Term Incentive Plan.

(b)“2020 Plan’s Available Reserve” means the number of unallocated shares, other than any Inducement Shares (as defined in the 2020 Plan), remaining available for grant under the 2020 Plan as of 12:01 a.m. Pacific Time on the Effective Date.

(c)“Adoption Date” means April 19, 2021, which is the date the Plan was adopted by the Compensation Committee of the Board.

(d)“Affiliate” means, at the time of determination, any “parent” or “subsidiary” of the Company as such terms are defined in Rule 405. The Board will have the authority to determine the time or times at which “parent” or “subsidiary” status is determined within the foregoing definition.

(e)“Award” means an Incentive Stock Option, a Nonstatutory Stock Option, a Stock Appreciation Right, a Restricted Stock Award, a Restricted Stock Unit Award, a Performance Stock Award or any Other Stock Award.

(f)“Award Agreement” means a written agreement between the Company and a Participant evidencing the terms and conditions of an Award.

(g)“Board” means the Board of Directors of the Company.

(h)“Capitalization Adjustment” means any change that is made in, or other events that occur with respect to, the Common Stock subject to the Plan or subject to any Award after the Adoption Date without the receipt of consideration by the Company through merger, consolidation, reorganization, recapitalization, reincorporation, stock dividend, dividend in property other than cash, large nonrecurring cash dividend, stock split, reverse stock split, liquidating dividend, combination of shares, exchange of shares, change in corporate structure or any similar equity restructuring transaction, as that term is used in Statement of Financial Accounting Standards No. 123 (revised). Notwithstanding the foregoing, the conversion of any convertible securities of the Company will not be treated as a Capitalization Adjustment.

(i)“Cause” will have the meaning ascribed to such term in any written agreement between a Participant and the Company or an Affiliate defining such term and, in the absence of such agreement, such term means, with respect to a Participant, a determination by the Board that (i) there has been a violation by the Participant of any contract or agreement between the Participant and the Company or an Affiliate, or of any statutory duty owed to the Company or an Affiliate, or a significant violation by the Participant of any policy of the Company or an Affiliate, (ii) the Participant has been engaged in disloyalty to the Company or an Affiliate (including, without limitation, fraud, embezzlement, theft, commission of a felony or proven dishonesty in the course of his or her employment or service), (iii) there has been an unauthorized use or disclosure by the Participant of trade secrets or confidential information of the Company or an Affiliate to persons not entitled to receive such information, (iv) the Participant has breached any written noncompetition or nonsolicitation agreement between the Participant and the Company or an Affiliate, (v) there has been gross misconduct by the Participant, (vi) there has been a material failure or refusal by the Participant to perform his or her employment duties, or to comply with reasonable directions of the Board (or the Participant’s supervisor), for a period of 30 days following receipt of notice from the Board (or the Participant’s supervisor) of such failure or refusal to perform or comply, or (vii) the Participant has engaged in such other behavior detrimental to the interests (financial, reputational, or otherwise) of the Company or an Affiliate as the Board determines in its sole discretion. Any determination that the Continuous Service of a Participant was terminated with or without Cause or that the Participant has engaged in conduct constituting Cause, in each case for the purposes of outstanding Awards held by the Participant, will have no effect upon any determination of the rights or obligations of the Company or the Participant for any other purpose.

(j)“Change in Control” means the occurrence, in a single transaction or in a series of related transactions, of any one or more of the following events:

(i)any Exchange Act Person becomes the Owner, directly or indirectly, of securities of the Company representing more than 50% of the combined voting power of the Company’s then outstanding securities eligible to vote for the election of the Board (the “Company Voting Securities”) other than by virtue of a merger, consolidation or similar transaction. Notwithstanding the foregoing, a Change in Control will not be deemed to occur (A) on account of the acquisition of securities of the Company directly from the Company, if a majority of the Incumbent Directors approves in advance the acquisition of Ownership of 50% or more of Company Voting Securities by such person, or (B) solely because the level of Ownership held by any Exchange Act Person (the “Subject Person”) exceeds the designated percentage threshold of the outstanding Company Voting Securities as a result of a repurchase or other acquisition of securities by the Company reducing the number of shares outstanding, provided that if a Change in Control would occur (but for the operation of this sentence) as a result of the acquisition of securities by the Company, and after such share acquisition, the Subject Person becomes the Owner of any additional Company Voting Securities that, assuming the repurchase or other acquisition had not occurred, increases the percentage of the then outstanding Company Voting Securities Owned by the Subject Person over the designated percentage threshold, then a Change in Control will be deemed to occur;

(ii)The consummation of a merger, consolidation, statutory share exchange or similar form of corporate transaction involving the Company or any of its Affiliates that requires the approval of the Company’s stockholders, whether for such transaction or the issuance of securities in the transaction (a “Business Combination”), unless immediately following such Business Combination: (A) more than 60% of the total voting power of (x) the corporation resulting from such Business Combination (the “Surviving Corporation”), or (y) if applicable, the ultimate parent corporation that directly or indirectly has beneficial ownership of 100% of the voting securities eligible to elect directors of the Surviving Corporation (the “Parent Corporation”), is represented by Company Voting Securities that were outstanding immediately prior to such Business Combination (or, if applicable, is represented by shares into which such Company Voting Securities were converted pursuant to such Business

Combination), and such voting power among the holders thereof is in substantially the same proportion as the voting power of such Company Voting Securities among the holders thereof immediately prior to the Business Combination, (B) no person (other than any employee benefit plan (or related trust) sponsored or maintained by the Surviving Corporation or the Parent Corporation), is or becomes the beneficial owner, directly or indirectly, of 50% or more of the total voting power of the outstanding voting securities eligible to elect directors of the Parent Corporation (or, if there is no Parent Corporation, the Surviving Corporation) and (C) at least a majority of the members of the board of directors of the Parent Corporation (or, if there is no Parent Corporation, the Surviving Corporation) following the consummation of the Business Combination were Incumbent Directors at the time of the Board’s approval of the execution of the initial agreement providing for such Business Combination;

(iv)over a period of 24 months or less, individuals who, on the Adoption Date, are members of the Board (the “Incumbent Directors”) cease for any reason to constitute at least a majority of the members of the Board; provided, however, that if the appointment or election (or nomination for election) of any new Board member was approved or recommended by a majority vote of the Incumbent Directors then still in office, such new member will, for purposes of this Plan, be considered as an Incumbent Director; provided, however, that, for this purpose, no individual initially elected or nominated as a member of the Board as a result of an actual or threatened election contest with respect to Board membership or as a result of any other actual or threatened solicitation of proxies by or on behalf of any person other than the Board shall be deemed to be an Incumbent Director; or

(k)“Code” means the Internal Revenue Code of 1986, as amended, including any applicable regulations and guidance thereunder.

(l)“Committee” means a committee of one or more Directors to whom authority has been delegated by the Board in accordance with Section 2(c).

(m)“Common Stock” means the common stock of the Company.

(n)“Company” means Arena Pharmaceuticals, Inc., a Delaware corporation.

(o)“Consultant” means any person, including an advisor, who is (i) engaged by the Company or an Affiliate to render consulting or advisory services and is compensated for such services, or (ii) serving as a member of the board of directors of an Affiliate and is compensated for such services. However, service solely as a Director, or payment of a fee for such service, will not cause a Director to be considered a “Consultant” for purposes of the Plan. Notwithstanding the foregoing, a person is treated as a Consultant under this Plan only if a Form S-8 Registration Statement under the Securities Act is available to register either the offer or the sale of the Company’s securities to such person.

(p)“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. A change in the capacity in which the Participant renders service to the Company or an Affiliate as an Employee, Director or Consultant, 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 service with the Company or an Affiliate, will not terminate a Participant’s Continuous Service; provided, however, that if the Entity for which a Participant is rendering services ceases to qualify as an Affiliate, as determined by the Board, in its sole discretion, such Participant’s Continuous Service will be considered to have terminated on the date such Entity ceases to qualify as an Affiliate. For example, a change in status from an Employee of the Company to a Consultant of an Affiliate or to a Director will not constitute an interruption of Continuous Service. To the extent permitted by law, the Board or the chief executive officer of the Company, in that party’s sole discretion, may determine whether Continuous Service will be considered interrupted in the case of (i) any leave of absence approved by the Board or chief executive officer, including sick leave, military leave or any other personal leave, or (ii) transfers between the Company, an Affiliate or their successors. Notwithstanding the foregoing, a leave of absence will be treated as Continuous Service for purposes of vesting in an Award only to such extent as may be provided in the Company’s or Affiliate’s leave of absence policy, in the written terms of any leave of absence agreement or policy applicable to the Participant, or as otherwise required by law.

(q)“Corporate Transaction” means the occurrence, in a single transaction or in a series of related transactions, of any one or more of the following events:

(i)the consummation of a sale or other disposition of all or substantially all, as determined by the Board, in its sole discretion, of the consolidated assets of the Company and its Subsidiaries;

    If required for compliance with Section 409A of the Code, in no event will an event be deemed a Corporate Transaction if such event is not also a “change in the ownership of” the Company, a “change in the effective control of” the Company or a “change in the ownership of a substantial portion of the assets of” the Company, each as determined under Treasury Regulations Section 1.409A-3(i)(5) (without regard to any alternative definition thereunder). The Board may, in its sole discretion and without a Participant’s consent, amend the definition of “Corporate Transaction” to conform to the definition of a “change in control event” under Section 409A of the Code and the regulations thereunder.

(r)“Director” means a member of the Board.

(s)“Disability” means, with respect to a Participant, the inability of such Participant to engage in any substantial gainful activity by reason of any medically determinable physical or mental impairment that can be expected to result in death or that has lasted or can be expected to last for a continuous period of not less than 12 months, as provided in Sections 22(e)(3) and 409A(a)(2)(c)(i) of the Code, and will be determined by the Board on the basis of such medical evidence as the Board deems warranted under the circumstances.

(t)“Effective Date” means the effective date of this Plan, which is the date of the Annual Meeting of Stockholders of the Company held in 2021, provided that this Plan is approved by the Company’s stockholders at such meeting.

(u)“Employee” means any person employed by the Company or an Affiliate. However, service solely as a Director, or payment of a fee for such services, will not cause a Director to be considered an “Employee” for purposes of the Plan.

(v)“Entity” means a corporation, partnership, limited liability company or other entity.

(w)“Exchange Act” means the Securities Exchange Act of 1934, as amended, and the rules and regulations promulgated thereunder.

(x)“Exchange Act Person” means any natural person, Entity or “group” (within the meaning of Section 13(d) or 14(d) of the Exchange Act), except that “Exchange Act Person” will not include (i) the Company or any Subsidiary of the Company, (ii) any employee benefit plan of the Company or any Subsidiary of the Company or any trustee or other fiduciary holding securities under an employee benefit plan of the Company or any Subsidiary of the Company, (iii) an underwriter temporarily holding securities pursuant to a registered public offering of such securities, (iv) an Entity Owned, directly or indirectly, by the stockholders of the Company in substantially the same proportions as their Ownership of stock of the Company, or (v) any natural person, Entity or “group” (within the meaning of Section 13(d) or 14(d) of the Exchange Act) that, as of the Effective Date, is the Owner, directly or

indirectly, of securities of the Company representing more than fifty percent 50% of the combined voting power of the Company’s then outstanding securities.

(y)“Fair Market Value” means, as of any date, the value of the Common Stock determined as follows:

(z)“Incentive Stock Option” means an option granted pursuant to Section 5 that is intended to be, and that qualifies as, an “incentive stock option” within the meaning of Section 422 of the Code.

(aa)“Inducement Award” means an Award that is granted pursuant to Section 3(f).

(ab)“Inducement Award Rules” means Nasdaq Listing Rule 5635(c)(4), the related guidance under Nasdaq IM-5635-1 and any successor rule or guidance.

(ac)“Inducement Share Reserve” will have the meaning set forth in Section 3(f).

(ad)“Inducement Shares” will have the meaning set forth in Section 3(f).

(ae)“Non-Employee Director” means a Director who either (i) is not a current employee or officer of the Company or an Affiliate, does not receive compensation, either directly or indirectly, from the Company or an Affiliate 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 pursuant to the Securities Act (“Regulation S-K”)), does not possess an interest in any other transaction for which disclosure would be required under Item 404(a) of Regulation S-K, and is not engaged in a business relationship for which disclosure would be required pursuant to Item 404(b) of Regulation S-K, or (ii) is otherwise considered a “non-employee director” for purposes of Rule 16b-3.

(af)“Nonstatutory Stock Option” means an option granted pursuant to Section 5 that does not qualify as an Incentive Stock Option.

(ag)“Officer” means a person who is an officer of the Company within the meaning of Section 16 of the Exchange Act.

(ah)“Option” means an Incentive Stock Option or a Nonstatutory Stock Option to purchase shares of Common Stock granted pursuant to the Plan.

(ai)“Option Agreement” means a written agreement between the Company and a holder of an Option evidencing the terms and conditions of an Option grant. Each Option Agreement will be subject to the terms and conditions of the Plan.

(aj)“Other Stock Award” means an award based in whole or in part by reference to the Common Stock which is granted pursuant to the terms and conditions of Section 6(d).

(ak)“Other Stock Award Agreement” means a written agreement between the Company and a holder of an Other Stock Award evidencing the terms and conditions of an Other Stock Award grant. Each Other Stock Award Agreement will be subject to the terms and conditions of the Plan.

(al)“Own,” “Owned,” “Owner,” “Ownership” A person or Entity will be deemed to “Own,” to have “Owned,” to be the “Owner” of, or to have acquired “Ownership” of securities if such person or Entity, directly or indirectly, through any contract, arrangement, understanding, relationship or otherwise, has or shares voting power, which includes the power to vote or to direct the voting, with respect to such securities.

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

(an)“Performance Criteria” means the one or more criteria that the Board will select for purposes of establishing the Performance Goals for a Performance Period. The Performance Criteria that will be used to establish such Performance Goals may be based on any one of, or combination of, the following, as determined by the Board: (i) earnings (including earnings per share and net earnings); (ii) earnings before interest, taxes and depreciation; (iii) earnings before interest, taxes, depreciation and amortization (EBITDA); (iv) total stockholder return; (v) return on equity or average stockholder’s equity; (vi) return on assets, investment, or capital employed; (vii) stock price or stock price performance; (viii) margin (including gross margin); (ix) net income (before or after taxes); (x) operating income; (xi) operating income after taxes; (xii) pre-tax profit; (xiii) operating cash flow; (xiv) sales or revenue targets; (xv) increases in revenue or product revenue; (xvi) expenses and cost reduction goals; (xvii) improvement in or attainment of working capital levels; (xviii) economic value added (or an equivalent metric); (xix) market share; (xx) cash flow; (xxi) cash flow per share; (xxii) share price performance; (xxiii) debt reduction; (xxiv) implementation or completion of projects or processes; (xxv) customer satisfaction; (xxvi) stockholders’ equity; (xxvii) capital expenditures; (xxviii) debt levels; (xxix) operating profit or net operating profit; (xxx) workforce diversity; (xxxi) growth of net income or operating income; (xxxii) billings; (xxxiii) submission to, or approval by, a regulatory body (including but not limited to the U.S. Food and Drug Administration) of an applicable filing for a product candidate or other product development milestones; (xxxiv) acquisitions, divestitures, joint ventures, strategic alliances, licenses or collaborations; (xxxv) spin-offs, split-ups, reorganizations, recapitalizations, restructurings, financings (debt or equity) or refinancings; (xxxvi) manufacturing or process development, clinical trial, regulatory, intellectual property, compliance or research objectives; and (xxxvii) any other measures of performance selected by the Board. Partial achievement of the specified criteria may result in the payment or vesting corresponding to the degree of achievement as specified in the applicable Award Agreement.

(ao)“Performance Goals” means, for a Performance Period, the one or more goals established by the Board for the Performance Period based upon the Performance Criteria. Performance Goals may be based on a Company-wide basis, with respect to one or more business units, divisions, Affiliates, or business segments, and in either absolute terms or relative to the performance of one or more comparable companies or the performance of one or more relevant indices. The Board is authorized to make appropriate adjustments in the method of calculating the attainment of Performance Goals for a Performance Period as follows: (i) to exclude restructuring and/or other nonrecurring charges; (ii) to exclude exchange rate effects, as applicable, for non-U.S. dollar denominated Performance Goals; (iii) to exclude the effects of changes to generally accepted accounting principles; (iv) to exclude the effects of any statutory adjustments to corporate tax rates; (v) to exclude the effects of items that are “unusual” in nature or occur “infrequently” as determined under generally accepted accounting principles; (vi) to exclude the dilutive effects of acquisitions or joint ventures; (vii) to assume that any business divested by the Company achieved performance objectives at targeted levels during the balance of a Performance Period following such divestiture; (viii) to exclude the effect of any change in the outstanding shares of common stock of the Company by reason of any stock dividend or split, stock repurchase, reorganization, recapitalization, merger, consolidation, spin-off, combination or exchange of shares or other similar corporate change, or any distributions to common stockholders other than regular cash dividends; (ix) to exclude the effects of stock based compensation and/or the award of an annual cash incentive under any annual incentive program maintained by the Company; (x) to exclude the effect of any other unusual, non-recurring gain or loss or other extraordinary item; and (xi) to make other appropriate adjustments selected by the Board.

(ap)“Performance Period” means the period of time selected by the Board over which the attainment of one or more Performance Goals will be measured for the purpose of determining a Participant’s right to and the payment of a Performance Stock Award. Performance Periods may be of varying and overlapping duration, at the sole discretion of the Board.

(aq)“Performance Stock Award” means an Award granted under the terms and conditions of Section 6(c).

(ar)“Plan” means this Arena Pharmaceuticals, Inc. 2021 Long-Term Incentive Plan.

(as)“Prior Plan Award” means an award granted under any of the Prior Plans that is outstanding as of the Effective Date.

(at)“Prior Plans” means, collectively, (i) the Arena Pharmaceuticals, Inc. 2009 Long-Term Incentive Plan, (ii) the Arena Pharmaceuticals, Inc. 2012 Long-Term Incentive Plan, (iii) the Arena Pharmaceuticals, Inc. 2013 Long-Term Incentive Plan, (iv) the Arena Pharmaceuticals, Inc. 2017 Long-Term Incentive Plan, and (v) the 2020 Plan.

(au)“Prior Plans’ Returning Shares” means: (i) any shares of Common Stock subject to a Prior Plan Award that on or following the Effective Date are not issued because such Prior Plan Award or any portion thereof expires or otherwise terminates without all of the shares covered by such Prior Plan Award having been issued; (ii) any shares of Common Stock subject to a Prior Plan Award that on or following the Effective Date are not issued because such Prior Plan Award or any portion thereof is settled in cash; and (iii) any shares of Common Stock issued

pursuant to a Prior Plan Award that on or following the Effective Date are forfeited back to or repurchased by the Company because of the failure to meet a contingency or condition required for the vesting of such shares.

(av)“Restricted Stock Award” means an award of shares of Common Stock which is granted pursuant to the terms and conditions of Section 6(a).

(aw)“Restricted Stock Award Agreement” means a written agreement between the Company and a holder of a Restricted Stock Award evidencing the terms and conditions of a Restricted Stock Award grant. Each Restricted Stock Award Agreement will be subject to the terms and conditions of the Plan.

(ax)“Restricted Stock Unit Award” means a right to receive shares of Common Stock which is granted pursuant to the terms and conditions of Section 6(b).

(ay)“Restricted Stock Unit Award Agreement” means a written agreement between the Company and a holder of a Restricted Stock Unit Award evidencing the terms and conditions of a Restricted Stock Unit Award grant. Each Restricted Stock Unit Award Agreement will be subject to the terms and conditions of the Plan.

(az)“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.

(ba)“Rule 405” means Rule 405 promulgated under the Securities Act.

(bb)“Securities Act” means the Securities Act of 1933, as amended, and the rules and regulations promulgated thereunder.

(bc)“Stock Appreciation Right” or “SAR” means a right to receive the appreciation on Common Stock that is granted pursuant to the terms and conditions of Section 5.

(bd)“Stock Appreciation Right Agreement” or “SAR Agreement” means a written agreement between the Company and a holder of a Stock Appreciation Right evidencing the terms and conditions of a Stock Appreciation Right grant. Each Stock Appreciation Right Agreement will be subject to the terms and conditions of the Plan.

(be)“Subsidiary” means, with respect to the Company, (i) any corporation of which more than 50% of the outstanding capital stock having ordinary voting power to elect a majority of the board of directors of such corporation (irrespective of whether, at the time, stock of any other class or classes of such corporation will have or might have voting power by reason of the happening of any contingency) is at the time, directly or indirectly, Owned by the Company, and (ii) any partnership, limited liability company or other entity in which the Company has a direct or indirect interest (whether in the form of voting or participation in profits or capital contribution) of more than 50%.

(bf)“Substitute Award” means an Award granted or shares of Common Stock issued by the Company under the Plan in assumption of, or in substitution or exchange for, an award previously granted, or the right or obligation to make a future award, in each case by a company acquired by the Company or an Affiliate or with which the Company or an Affiliate combines.

(bg)“Ten Percent Stockholder” means a person who Owns (or is deemed to Own pursuant to Section 424(d) of the Code) stock possessing more than 10% of the total combined voting power of all classes of stock of the Company or any Affiliate.

(bh)“Transaction” means a Corporate Transaction or a Change in Control.