AGENUS INC. 2009 EQUITY INCENTIVE PLAN (As amended through June 13, 2012)

1. Purpose and Eligibility

The purpose of this 2009 Equity Incentive Plan (the “Plan”) of Agenus Inc., a Delaware corporation (the “Company”), is to provide stock options and other equity interests in the Company (each an “Award”) to employees, officers, directors, consultants and advisors of the Company and its Subsidiaries, all of whom are eligible to receive Awards under the Plan, other than a person who has irrevocably elected not to be eligible. Any person to whom an Award has been granted under the Plan is called a “Participant.” Additional definitions are contained in Section 8.

2. Administration

a. Administration by Board of Directors. The Plan will be administered by the Board of Directors of the Company (the “Board”). The Board, in its sole discretion, shall have the authority to grant and amend Awards, to adopt, amend and repeal rules relating to the Plan and to interpret and correct the provisions of the Plan and any Award. All decisions by the Board shall be final and binding on all interested persons. Neither the Company nor any member of the Board shall be liable for any action or determination relating to the Plan or any Award.

b. Appointment of Committees. To the extent permitted by applicable law, the Board may delegate any or all of its powers under the Plan to one or more committees or subcommittees of the Board (a “Committee”). All references in the Plan to the “Board” shall mean any such other Committee or the Board, as applicable. Discretionary Awards to non-employee directors will only be granted and administered by a Committee, each member of which is an “independent director” as defined in the applicable NASDAQ Marketplace Rules.

c. Delegation to Officers. To the extent permitted by applicable law, the Board may delegate to one or more officers of the Company the power to grant Awards to employees or officers of the Company or any of its present or future parent or subsidiary corporations and to exercise such other powers under the Plan as the Board may determine, provided that no officer shall be authorized to grant Awards to any “executive officer” of the Company (as defined by Rule 3b-7 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”) or to any “officer” of the Company (as defined by Rule 16a-1 under the Exchange Act).

3. Stock Available for Awards

a. Number of Shares. Subject to adjustment under Section 3(b), the aggregate number of shares of Common Stock of the Company (the “Common Stock”) that may be issued pursuant to the Plan is 4,200,000 shares. If any Award expires, or is terminated, surrendered or forfeited, in whole or in part, the unissued Common Stock covered by such Award shall again be available for

the grant of Awards under the Plan. If shares of Common Stock issued pursuant to the Plan are repurchased by, or are surrendered or forfeited to, the Company at no more than the original purchase price thereof, such shares of Common Stock shall again be available for the grant of Awards under the Plan. The Board may adopt such share counting rules as it deems appropriate, provided that such rules are not inconsistent with the Plan.

b. Adjustment to Common Stock. In the event of any stock split, stock dividend, extraordinary cash dividend, recapitalization, reorganization, merger, consolidation, combination, exchange of shares, liquidation, spin-off, split-up, or other similar change in capitalization or event, (i) the number and class of securities available for Awards under the Plan, (ii) the number and class of securities, vesting schedule and exercise price per share subject to each outstanding Option, (iii) the repurchase price per security subject to repurchase, and (iv) the terms of each other outstanding Award shall be adjusted by the Board (or substituted Awards may be made) to avoid an unfair result. If Section 7(e)(i) applies for any event, this Section 3(b) shall not be applicable.

4. Stock Options

a. General. The Board may grant options to purchase Common Stock (each, an “Option”) and determine the number of shares of Common Stock to be covered by each Option, the exercise price of each Option and the conditions and limitations applicable to the exercise of each Option and the Common Stock issued upon the exercise of each Option, including vesting provisions, repurchase provisions and restrictions relating to applicable federal or state securities laws, as it considers advisable.

b. Incentive Stock Options. An Option that the Board intends to be an “incentive stock option,” as defined in Section 422 of the Code (an “Incentive Stock Option” ), shall be granted only to employees of the Company and any other entity the employees of which are entitled to receive Incentive Stock Options under the Code. All Incentive Stock Options that are granted pursuant to the Plan shall be subject to, and shall be construed consistently with, the requirements of Section 422 of the Code. The Board and the Company shall have no liability if an Option or any part thereof that is intended to be an Incentive Stock Option does not qualify as such. An Option or any part thereof that does not qualify as an Incentive Stock Option is referred to herein as a “Nonstatutory Stock Option.”

c. Exercise Price. The Board shall establish the exercise price (or determine the method by which the exercise price shall be determined) at the time each Option is granted and specify such exercise price in the applicable option agreement, provided, however, that the exercise price shall be not less than 100% of the fair market value of the shares subject thereto at the time of grant, as determined by the Board.

d. Duration of Options. Each Option shall be exercisable at such times and subject to such terms and conditions as the Board may specify in the applicable option agreement, provided, however, that no Option will be granted for a term in excess of 10 years.

e. Exercise of Option. Options may be exercised only by delivery to the Company of a written notice of exercise signed by the proper person, or any other form of notice approved by the Board, together with payment in full as specified in Section 4(f) for the number of shares for which the Option is exercised.

f. Payment Upon Exercise. No shares shall be delivered pursuant to any exercise of an Option until the Company receives payment in full of the option exercise price in the manner provided in the applicable option agreement. Methods of payment may include any of the following or any combination thereof or any other form of lawful consideration: (i) cash, check or wire transfer of funds; (ii) promissory note; (iii) shares of Common Stock owned by the Participant valued at fair market value (as determined by the Board or as determined pursuant to the applicable option agreement); (iv) so-called “cashless exercise” or “net issuance”; and (v) arrangements with a broker or other financial institution for the prompt payment of the exercise price to the Company.

g. Repricing. The Board may, without stockholder approval, amend any outstanding Option granted under the Plan to provide an exercise price per share that is lower than the then-current exercise price per share of such outstanding Option. The Board may also, without stockholder approval, cancel any outstanding Option and grant in substitution therefor new Options covering the same or a different number of shares of Common Stock and having an exercise price per share lower than the then-current exercise price per share of the cancelled Option.

h. No Reload Rights. No Option granted under the Plan shall contain any provision entitling the optionee to the automatic grant of additional Options in connection with any exercise of the original Option.

5. Stock Awards

a. Grants. The Board may grant Awards entitling recipients to acquire shares of Common Stock for any lawful consideration (a “Stock Award”). The Board may, but need not, provide that such Stock Award shall be subject to forfeiture to the Company in the event that conditions specified by the Board in the applicable Award are not satisfied prior to the end of the applicable restriction period or periods established by the Board for such Award (a “Restricted Stock Award” ).

b. Terms and Conditions. The Board shall determine the terms and conditions of any such Stock Award. In the case of a Restricted Stock Award, any stock certificates issued in respect thereof shall be registered in the name of the Participant and, unless otherwise determined by the Board, deposited by the Participant, together with a stock power endorsed in blank, with the Company (or its designee). After the expiration of the applicable restriction periods, the Company (or such designee) shall deliver the certificates no longer subject to such restrictions to the Participant or, if the Participant has died, to the beneficiary designated by a Participant, in a manner determined by the Board, to receive amounts due or exercise rights of the Participant in the event of the Participant’s death (the “Designated Beneficiary”). In the absence of an effective designation by a Participant, Designated Beneficiary shall mean the Participant’s estate.

6. Other Stock-Based Awards

The Board shall have the right to grant other Awards based upon or with reference to the Common Stock or the trading price thereof and having such terms and conditions as the Board may determine, including, without limitation, the grant or sale of shares of stock based upon certain conditions, the grant of securities convertible into Common Stock and the grant of stock appreciation rights, phantom stock awards or stock units, which may be settled in cash or stock.

7. General Provisions Applicable to Awards

a. Transferability of Awards. Except as the Board may otherwise determine or provide in an Award, Awards shall not be sold, assigned, transferred, pledged or otherwise encumbered by the person to whom they are granted, either voluntarily or by operation of law, except by will or the laws of descent and distribution, and, during the life of the Participant, shall be exercisable only by the Participant. References to a Participant, to the extent relevant in the context, shall include references to authorized transferees.

b. Documentation. Each Award shall be evidenced by an instrument in such form as the Board shall determine or as executed by an officer of the Company pursuant to authority delegated by the Board. Each Award may contain terms and conditions in addition to those set forth in the Plan, provided that such terms and conditions do not contravene the provisions of the Plan. If a person to whom an Award has been granted fails to execute and deliver to the Company within the time specified by the Company the form of Award instrument specified by the Company, such Award shall be voidable by the Company at its election, with or without notice to such person.

c. Board Discretion. The terms of each type of Award need not be identical, and the Board need not treat Participants uniformly.

d. Termination of Status. The Board shall determine the effect on an Award of the disability, death, retirement, authorized leave of absence or other change in the employment or other status of a Participant and the extent to which, and the period during which, the Participant, or the Participant’s legal representative, conservator, guardian or Designated Beneficiary, may exercise rights under the Award.

e. Acquisition of the Company.

(i) Consequences of an Acquisition. In connection with an Acquisition (as defined below), the Board or the board of directors of the surviving or acquiring entity (as used in this Section 7(e)(i), also the “Board”) shall as to outstanding Awards (on the same basis or on different bases as the Board shall specify) make appropriate provision for the continuation of such Awards by the Company or the assumption of, or substitution for, such Awards by the surviving or acquiring entity and by substituting on an equitable basis for the shares then subject to such Awards either (a) the consideration payable with respect to the outstanding shares of Common Stock in connection with the Acquisition, (b) shares of stock of the surviving or acquiring corporation or (c) such other securities or

other consideration as the Board deems appropriate, the fair market value of which (as determined by the Board in its sole discretion) shall not materially differ from the fair market value of the shares of Common Stock subject to such Awards immediately preceding the Acquisition. In addition to, in lieu of, or in combination with the foregoing, with respect to unexercised Options or other unexercised Awards, the Board may, on the same basis or on different bases as the Board shall specify, upon written notice to the affected Participants, provide that one or more such Options or Awards (or the vested portion thereof) must be exercised, in whole or in part, within a specified number of days of the date of such notice, at the end of which period such unexercised Options or unexercised Awards (or the vested portion thereof) shall terminate in their entirety, and/or provide that one or more unexercised Options or unexercised Awards (or the vested portion thereof), in whole or in part, shall be terminated in their entirety in exchange for a cash payment equal to the fair market value (as determined by the Board in its sole discretion) for the shares subject to such unexercised Options or unexercised Awards (or the vested portion thereof) minus the exercise price thereof, if applicable. Unless otherwise determined by the Board (on the same basis or on different bases as the Board shall specify), any repurchase rights, vesting provisions or other rights of the Company that relate to an Option or other Award shall continue to apply to consideration, including cash, that has been substituted, assumed or amended for an Option or other Award pursuant to this paragraph. The Company may hold in escrow all or any portion of any such consideration in order to effectuate any continuing restrictions.

(ii) Acquisition Defined. An “Acquisition” shall mean: (x) the sale of the Company by merger in which the stockholders of the Company in their capacity as such no longer own a majority of the outstanding equity securities of the Company (or its successor); or (y) any sale of all or substantially all of the assets or capital stock of the Company (other than in a spin-off or similar transaction) or (z) any other change of control or acquisition of the business of the Company, as determined by the Board.

(iii) Assumption of Options Upon Certain Events. In connection with a merger or consolidation of an entity with the Company or a Subsidiary or the acquisition by the Company of property or stock of an entity, the Board may grant Awards under the Plan in substitution for stock and stock-based awards issued by such entity or an affiliate thereof. The substitute Awards shall be granted on such terms and conditions as the Board considers appropriate in the circumstances. Substitute Options may be granted on such terms as the Board deems appropriate in the circumstances, notwithstanding any limitations on Options contained elsewhere herein. Substitute Options shall not count against the overall share limit set forth in Section 3(a), except as may be required by reason of Section 422 and related provisions of the Code.

f. Withholding. Each Participant shall pay to the Company, or make provisions satisfactory to the Company for payment of, any taxes required by law to be withheld in connection with Awards to such Participant no later than the date of the event creating the tax liability. The Board may allow Participants to satisfy such tax obligations in whole or in part by transferring shares of Common Stock, including shares retained from the Award creating the tax

obligation, valued at their fair market value (as determined by the Board or as determined pursuant to the applicable Award). The Company may, to the extent permitted by law, deduct any such tax obligations from any payment of any kind otherwise due to a Participant. The Board may impose such restrictions in connection therewith as may be necessary to avoid any transaction that might give rise to liability under Section 16(b) of the Exchange Act.

g. Amendment of Awards. The Board may amend, modify or terminate any outstanding Award under certain circumstances including, but not limited to, if the Board determines that the provisions of the Plan or any Award are in contravention of any law or regulation of any governmental entity or self-regulatory organization with jurisdiction over the Company, or would have material adverse effects on the taxation of the Company or the Participant. In connection therewith, the Board may substitute for any such Award another Award of the same or a different type, change the date of exercise or realization, convert an Incentive Stock Option to a Nonstatutory Stock Option or effect any other modification or amendment, provided that the Participant’s consent to such action shall be required unless the Board determines that the action, taking into account any related action, would not materially and adversely affect the Participant.

h. Conditions on Delivery of Stock. The Company will not be obligated to deliver any shares of Common Stock pursuant to the Plan or to remove restrictions from shares previously delivered under the Plan until (i) all conditions of the Award have been met or removed to the satisfaction of the Company, (ii) in the opinion of the Company’s counsel, all other legal matters in connection with the issuance and delivery of such shares have been satisfied, including any applicable securities laws and any applicable stock exchange or stock market rules and regulations, and (iii) the Participant has executed and delivered to the Company such representations or agreements as the Company may consider appropriate to satisfy the requirements of any applicable laws, rules or regulations.

i. Acceleration. The Board may at any time provide that any Options shall become immediately exercisable in full or in part, that any Restricted Stock Awards shall be free of some or all restrictions, or that any other stock-based Awards may become exercisable in full or in part or free of some or all restrictions or conditions, or otherwise realizable in full or in part, as the case may be, despite the fact that the foregoing actions may (i) cause the application of Sections 280G and 4999 of the Code if a change in ownership or control of the Company occurs, or (ii) disqualify all or part of the Option as an Incentive Stock Option. In the event of the acceleration of the exercisability of one or more outstanding Options, including pursuant to paragraph (e)(i), the Board may provide, as a condition of full exercisability of any or all such Options, that the Common Stock or other substituted consideration, including cash, as to which exercisability has been accelerated shall be restricted and subject to forfeiture back to the Company at the option of the Company at the cost thereof upon termination of employment or other relationship, with the timing and other terms of the vesting of such restricted stock or other consideration being equivalent to the timing and other terms of the superseded exercise schedule of the related Option.

j. Settlement. The Board shall determine whether Awards are settled in whole or in part in cash, Common Stock, other securities of the Company, Awards or other property.

k. Dividends and Cash Awards. In the discretion of the Board, any Award under the Plan may provide the Participant with (i) dividends or dividend equivalents payable currently or deferred with or without interest, and (ii) cash payments in lieu of or in addition to an Award.

l. Loans. The Board may authorize the making of loans or cash payments to Participants in connection with any Award under the Plan, which loans may be secured by any security, including Common Stock, underlying or related to such Award (provided that such Loan shall not exceed the fair market value of the security subject to such Award), and which may be forgiven upon such terms and conditions as the Board may establish at the time of such loan or at any time thereafter.

m. Use for Settlement or Compensation. Awards may be made available as a form of payment in the settlement of other Awards granted under the Plan or as payment in lieu of compensation to which a Participant is otherwise entitled.

8. Miscellaneous

a. Definitions.

(i) “Company,” for purposes of eligibility under the Plan, shall include any present or future subsidiary corporations of Agenus Inc., as defined in Section 424(f) of the Code (a “Subsidiary” ), and any future parent corporation of Agenus Inc., as defined in Section 424(e) of the Code. For purposes of Awards other than Incentive Stock Options, the term “Company” shall include any other business venture in which the Company has a direct or indirect significant interest, as determined by the Board in its sole discretion.

(ii) “Code” means the Internal Revenue Code of 1986, as amended, and any regulations promulgated thereunder.

(iii) “employee,” for purposes of eligibility under the Plan (but not for purposes of Section 4(b)), shall include a person to whom an offer of employment has been extended by the Company.

     b. No Right to Employment, Service on the Board or Other Status. No person shall have any claim or right to be granted an Award, and the grant of an Award shall not be construed as giving a Participant the right to continued employment, service on the Board or any other relationship with the Company. The Company expressly reserves the right at any time to dismiss or otherwise terminate its relationship with a Participant free from any liability or claim under the Plan.

c. No Rights As Stockholder. Subject to the provisions of the applicable Award, no Participant or Designated Beneficiary shall have any rights as a stockholder with respect to any shares of Common Stock to be distributed with respect to an Award until becoming the record holder thereof.

d. Effect on Other Benefit Plans. Unless specifically provided otherwise in an applicable Award, the amount of any compensation deemed to be received by a Participant as a result of the receipt or exercise of an Award will not constitute “earnings” with respect to which any other benefits of such Participant are determined, including without limitation benefits under any pension, profit sharing, life insurance or salary continuation plan.

e. Authorization of Sub-Plans. The Board may from time to time establish one or more sub-plans under the Plan for purposes of satisfying applicable blue sky, securities or tax laws of various jurisdictions. The Board shall establish such sub-plans by adopting supplements to this Plan containing (i) such limitations on the Board’s discretion under the Plan as the Board deems necessary or desirable or (ii) such additional terms and conditions not otherwise inconsistent with the Plan as the Board shall deem necessary or desirable. All supplements adopted by the Board shall be deemed to be part of the Plan, but each supplement shall apply only to Participants within the affected jurisdiction and the Company shall not be required to provide copies of any supplement to Participants in any jurisdiction which is not the subject of such supplement. Without limiting the generality of the foregoing, the Board may modify Awards granted to Participants who are foreign nationals or employed outside the United States or establish sub-plans or procedures under the Plan to recognize differences in laws, rules, regulations or customs of such foreign jurisdictions with respect to tax, securities, currency, employee benefit or other matters.

f. Effective Date and Term of Plan. The Plan shall become effective on the date on which it is approved by the Company’s stockholders. No Awards shall be granted under the Plan after the completion of ten years from the date on which the Plan was approved by the Company’s stockholders, but Awards previously granted may extend beyond that date.

g. Amendment of Plan. The Board may amend, suspend or terminate the Plan or any portion thereof at any time, subject to any required stockholder approval under any applicable legal, regulatory or listing requirement.

h. Governing Law. The provisions of the Plan and all Awards made hereunder shall be governed by and interpreted in accordance with the laws of Delaware, without regard to any applicable conflicts of law.

This Plan was originally approved by the Board of Directors on March 12, 2009.

This Plan was originally approved by the Stockholders on June 10, 2009.

Amendment No. 1 to this Plan was approved by the Board of Directors on March 15, 2012.

Amendment No. 1 to this Plan was approved by the Stockholders on June 13, 2012.