Base Annual Retainer. If a Non-Employee Director is elected or appointed to the Board at any time other than at an Annual Meeting, the Base Annual Retainer for the initial term that lasts from the date of election or appointment until the first Annual Meeting to occur thereafter will be reduced on a pro-rata basis, such that the amount payable will be equal to the Base Annual Retainer multiplied by a fraction, the numerator of which is 12 minus the whole number of months from the date of the preceding Annual Meeting until the date of election or appointment and the denominator of which is 12. Subject to Section 4 and Section 5, the RSU portion of the prorated Base Annual Retainer will be granted on the Base Annual Retainer Vesting Start Date. The number of RSUs granted will be calculated using the Fair Market Value (as defined in the Plan) of the Class A common stock of the Company as of the Base Annual Retainer Vesting Start Date, rounded down to the nearest whole RSU.

BASIC CASH RETAINER. Each Eligible Participant shall be paid a Basic Cash Retainer for service as a director during each Plan Year, payable in quarterly installments in advance. The amount of the Basic Cash Retainer is set forth on [Schedule I], which may be amended from time to time by the Committee. Each person who first becomes an Eligible Participant on a date other than an Annual Meeting Date shall be paid a pro rata amount of the Basic Cash Retainer for that Plan Year to reflect the actual number of days such Person will serve on the Board in the Plan Year (a “Prorated Basic Cash Retainer”). The first installment of a Prorated Basic Cash Retainer shall be paid on or about the first day that such Person becomes an Eligible Participant and shall be a pro rata amount of the Basic Cash Retainer for that fiscal quarter to reflect the actual number of days such Person will serve on the Board in that fiscal quarter, with normal quarterly installments to follow for the remainder of the Plan Year, as described above.

Annual Retainer Election. For each calendar year of the Non-Employee Director’s service, the Non-Employee Director will have the opportunity to elect in writing in a form provided by the Company and delivered to the Company, prior to January 1 of the applicable year, payment of the Annual Retainer in cash or an equivalent number of Restricted Stock Units (as defined in the Company’s 2014 Incentive Award Plan or any other applicable Company equity incentive plan then-maintained by the Company (the “Equity Plan”)), determined by dividing # the Annual Retainer by # the Fair Market Value (as defined in the Plan) of one share of the Company’s common stock on the last trading day prior to January 1 of the year to which the Annual Retainer relates. Restricted Stock Units will be issued under, and subject to the terms of, the Equity Plan and a separate restricted stock unit agreement and will vest, subject to the Non-Employee Director’s continued service, in one single installment on January 1 of the year following the year to which the Annual Retainer relates. Unless otherwise determined by the Board, unvested Restricted Stock Units will be forfeited upon the Non-Employee Director’s termination of service.

Equity. Notwithstanding the terms of any Equity Award, other than Equity Award terms more favorable to the Covered Employee, all Equity Awards held by the Covered Employee on the Date of Termination (other than Equity Awards that vest on the basis of performance and do not provide solely for time-based vesting) shall become 100% vested upon the Release Effective Date.

Equity. The equity awards held by the Executive shall continue to be governed by the terms and conditions of the Company’s applicable equity incentive plan(s) and the applicable award agreement(s) governing the terms of such equity awards held by the Executive (collectively, the “Equity Documents”); provided, however, and notwithstanding anything to the contrary in the Equity Documents, Section 6(a)(ii) of this Agreement shall apply in the event of a termination by the Company without Cause or by the Executive for Good Reason in either event within the Change in Control Period (as such terms are defined below).

Equity. During the Employment Term, Executive will be eligible to receive equity awards pursuant to any plans or arrangements the Company may have in effect from time to time. The Board or Committee will determine in its discretion whether Executive will be granted any equity awards and the terms of any equity award in accordance with the terms of any applicable plan or arrangement that may be in effect from time to time.

Equity. Within 5 days of the Date of Hire, the Employee shall be eligible to participate in Kaleido’s equity incentive program and be granted, at such time as the Board determines, an option to purchase 600,000 shares of common stock (such equity award is referred to as the “Equity Award”). Subject to the Board’s approval of the Equity Award, the Equity Award will vest according to the following schedule: 25% of the Equity Award will vest on the first anniversary of the Date of Hire, and the remaining 75% of the Equity Award will vest in equal installments at the end of each calendar quarter over the next three years, provided that, in each case, that the Employee continues to provide continuous services to the Company as of each such vesting date. The grant of the Equity Award will be conditioned upon, among other things, the Employee’s execution of all necessary documentation relating to the Equity Award as determined by the Company (all such documentation is collectively referred to as the “Equity Award Documentation”). In all respects, these options will be governed by the 2019 Stock Option and Incentive Plan and the applicable Stock Option Agreement.

Equity. Upon the commencement of your employment with the Company (the “Commencement Date”), the Company hereby grants to you, under the 2013 Stock Incentive Plan (the “Plan”), incentive stock options (or to the extent incentive stock options may not be granted, non-statutory stock options) to purchase shares of Common Stock at an exercise price equal to the closing price of the Common Stock on the Nasdaq Global Market on the Commencement Date; that the number of shares of Common Stock as to which such options shall be exercisable shall be equal to the number of shares of Common Stock that has a Black Scholes value as of the Commencement Date equal to $1,125,000 (as calculated using the same methodology that the Company then uses to calculate the value of stock awards for purposes of the Company’s financial statements); and that such grant of stock options shall be made pursuant to, and in accordance with, the terms of a stock option agreement that shall be entered into with you, containing such terms and in such form consistent with the form of agreement previously approved by the Epizyme Board of Directors and the 2013 Plan and providing generally, among other things, for such stock options to have a ten-year term and to vest over four years with 25% of the option vesting on the first anniversary of the Commencement Date and the balance of the option vesting thereafter in 36 equal monthly installments with the first such installment vesting on the date one month after the first anniversary of the Commencement Date.

Equity. On or as soon as practicable following the Effective Date, as an inducement to enter into this Agreement, the Company will grant Executive an option (the “Stock Option”) to purchase 200,000 shares of the Company’s common stock with a per-share exercise price equal to the fair market value of a share of the Company’s common stock on the date of grant, as determined by the Board or the compensation committee thereof. 1/4th of the shares underlying the Stock Option will vest and become exercisable on the one-year anniversary of the grant date, and 1/48th of the shares underlying the Stock Option will vest and become exercisable on a monthly basis thereafter, such that 100% of the shares underlying the Stock Option shall be vested and exercisable as of the four-year anniversary of the grant date, in each case so long as Executive remains employed by the Company through each applicable vesting date. The Stock Option will be subject to terms and conditions consistent with those provided in the Company’s 2014 Equity Incentive Plan, and will be governed in all respects by the terms of the stock option agreement to be entered into between Executive and the Company. Further details regarding the Stock Option will be provided to Executive upon approval of such grant by the Board.

Equity. Notwithstanding anything to the contrary in this Agreement or the applicable equity documents, if you: # comply with all obligations contained in this Agreement, excluding your obligations under the Consulting Agreement set forth in Section 5, and # timely sign and return the Termination of Services Release attached hereto as Exhibit C (the “Termination of Services Release”) the Company will accelerate the vesting of all unvested Stock Awards held by you as of the termination of the Consulting Period with respect to the portion of the shares subject thereto that would have vested during the twelve (12) month period following the termination of the Consulting Period, had you continued to provide services to the Company during such period. Furthermore, should you satisfy the conditions for receipt of the equity acceleration as set forth in the preceding sentence, effective as of the termination of the Consulting Period, your right to exercise any vested Stock Awards shall be extended until the date that is one (1) year following the termination of the Consulting Period (e.g. if the Consulting Period terminates September 16, 2021, the exercise period would be extended until September 16, 2022) (together with the equity acceleration, the “Equity Benefits”). You understand that as a result of the extended exercise period described above, applicable tax rules require that any options held by you that qualify for tax purposes as incentive stock options shall automatically be converted to non-statutory stock options for tax purposes as of the Effective Date of this Agreement according to the terms of the applicable equity incentive plan and of the Stock Awards thereunder, and that you shall consult your own tax advisor regarding the extended exercise period and the tax consequences of option transactions. Except as expressly modified herein, your Stock Awards will continue to be governed by the terms of the applicable equity incentive plan and other Stock Award documents, and your rights to exercise any vested Stock Awards shall be as set forth in the applicable equity incentive plan and/or the applicable Stock Award notices and agreements.