Exhibit 10.1

January 23, 2015

Andrew Singer

81 Skyway Lane

Oakland, CA 94619

Dear Andrew:

It is my pleasure to extend to you this offer of employment with Epizyme, Inc.
(the “Company”). On behalf of the Company, I am pleased to set forth below the
terms of your employment with the Company:

 

  1. Employment. You will be employed to serve on a full-time basis as the
Company’s Executive Vice President, Finance and Administration and Chief
Financial Officer, commencing on February 9, 2015 (the “Commencement Date”). As
Executive Vice President, Finance and Administration and Chief Financial
Officer, you will be responsible for such duties as are consistent with such
positions, plus such other duties as may from time to time be assigned to you by
the Company. You shall report to the Chief Executive Officer, and you agree to
devote your full business time, best efforts, skill, knowledge, attention and
energies to the advancement of the Company’s business and interests and to the
performance of your duties and responsibilities as an employee of the Company.
You agree to abide by the rules, regulations, instructions, personnel practices
and policies of the Company and any changes therein that may be adopted from
time to time by the Company.

 

  2. Base Salary. Your base salary will be at the rate of $16,666.67 per
semi-monthly pay period (which if annualized equals $400,000), less all
applicable taxes and withholdings, to be paid in installments in accordance with
the Company’s regular payroll practices. Such base salary may be adjusted from
time to time in accordance with normal business practices and in the sole
discretion of the Company.

 

  3. Discretionary Bonus. Following the end of each fiscal year and subject to
the approval of the Company’s Board of Directors, you may be eligible for a
retention and performance bonus, based on your performance and the Company’s
performance during the applicable fiscal year, as determined by the Company in
its sole discretion. Your target bonus is 40% of your annualized base salary.
Such target bonus may be adjusted from time to time in accordance with normal
business practices and in the sole discretion of the Company. You must be an
active employee of the Company on the date any bonus is distributed in order to
be eligible for and to earn a bonus award, as it also serves as an incentive to
remain employed by the Company.

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  4. Equity. Subject to Board approval, you will receive a stock option grant
under the Company’s 2013 Stock Incentive Plan (the “Plan”) for the purchase of
104,169 shares of common stock of the Company at an exercise price per share
equal to the fair market value of one share of Common Stock on the date of the
grant as determined by the Company in its sole discretion. The stock option
grant shall be subject to all terms and other provisions set forth in the Plan
and in a separate stock option agreement, including the vesting schedule. The
option will vest over a four-year period with the first quarter vesting on the
first anniversary of the Commencement Date and the remaining three-fourths
vesting monthly in 36 equal monthly installments following the first anniversary
of the Commencement Date and until fully vested on the fourth anniversary of the
Commencement Date, subject to your continued employment with the Company through
each vesting date.

In addition, you will be granted an award of 37,313 restricted stock units
(subject to appropriate adjustment for stock splits, stock dividends,
recapitalizations and similar events affecting the Common Stock after the date
hereof), pursuant and subject to the terms of a restricted stock unit agreement
entered into with the Company under the Plan (the “Initial Restricted Stock Unit
Agreement”). Under the Initial Restricted Stock Unit Agreement, upon the vesting
of the award, the Company will deliver to you for each restricted stock unit
that becomes vested one share of Common Stock (subject to appropriate adjustment
for stock splits, stock dividends, recapitalizations and similar events
affecting the Common Stock after the date hereof). In addition, under the
Initial Restricted Stock Unit Agreement, the award will vest over a four-year
period with the first quarter vesting on the first anniversary of the
Commencement Date and the remaining three-fourths vesting monthly in 36 equal
monthly installments following the first anniversary of the Commencement Date
and until fully vested on the fourth anniversary of the Commencement Date,
subject to your continued employment with the Company through each vesting date.

If you remain employed by the Company on the first anniversary of the
Commencement Date and a Change in Control (as defined under the Company’s
Executive Severance and Change in Control Plan) has not occurred, you will be
granted an award for a number of restricted stock units determined by the
Company pursuant and subject to the terms of a restricted stock unit agreement
entered into with the Company under the Plan (the “Second Restricted Stock Unit
Agreement”). The Company shall determine the number of restricted stock units to
be granted by dividing $750,000 by the closing price of the Common Stock on the
first anniversary of the Commencement Date (or the first trading day
thereafter). Under the Second Restricted Stock Unit Agreement, upon the vesting
of the award, the Company will deliver to you for each restricted stock unit
that becomes vested one share of Common Stock (subject to appropriate adjustment
for stock splits, stock dividends, recapitalizations and similar events
affecting the Common Stock after the date hereof). In addition, under the Second
Restricted Stock Unit Agreement, the award will vest over a three-year period
with the first quarter vesting on the first anniversary of the Commencement Date
and

 

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the remaining three-fourths vesting monthly in 36 equal monthly installments
following the first anniversary of the Commencement Date and until fully vested
on the fourth anniversary of the Commencement Date, subject to your continued
employment with the Company through each vesting date.

You may also be eligible for other grants of stock or stock options as
determined by and in the sole discretion of the Board. Nothing in this section
shall affect your status as an employee at will, as set for below.

 

  5. Relocation. You will also receive an additional one-time payment of
$200,000 for relocation expenses. Payment, less all applicable taxes and
withholdings, will be made if and only at such time as relocation to the greater
Boston area is both complete and by August 31, 2015. If you resign from the
Company voluntarily for any reason or are terminated by the Company for Cause
(as defined under the Company’s Executive Severance and Change in Control Plan)
within one year of the payment date, you will be responsible to repay 100% of
the relocation one-time payment ($200,000) less applicable taxes. If you resign
from the Company voluntarily for any reason or are terminated by the Company for
Cause after one year of the payment date, but before two years from your payment
date (months 13-24), you will be responsible to repay a pro-rata monthly
portion, of $100,000 less applicable taxes. We will provide temporary housing
for you for a period of up to six months, airfare and hotel for your travel to
and from the office between your start date and your actual move to the greater
Boston area in order to facilitate your relocation to the greater Boson area.
Taxes associated with travel, hotel, and temporary housing benefit will be paid
on your behalf by Epizyme. Any amounts owed under this Section 5 as a result of
you leaving the Company shall be repaid within 60 days of the date you cease to
be an employee of the Company, and the Company shall have the right to offset
such amounts against any amounts it owes you under this letter, the Company’s
Executive Severance and Change in Control Plan or otherwise.

 

  6. Benefits. You may participate in any and all benefit programs that the
Company establishes and makes available to its employees from time to time,
provided that you are eligible under (and subject to all provisions of) the plan
documents that govern those programs. Benefits are subject to change at any time
in the Company’s sole discretion.

 

  7. Vacation. You will be eligible for a maximum of three (3) weeks of paid
vacation per calendar year to be taken at such times as may be approved in
advance by the Company. The number of vacation days for which you are eligible
shall accrue at the rate of 1.25 days per month that you are employed during
such calendar year. Your accrual and use of vacation time will be pursuant to
Company policy, as established and as may be modified in the sole discretion of
the Company from time to time.

 

  8.

Invention, Non-Disclosure, Non-Competition and Non-Solicitation Obligations. In
exchange for your employment with the Company pursuant to the terms and

 

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  conditions herein, you hereby acknowledge and affirm your obligations set
forth in the enclosed Employee Confidentiality and Invention of Assignments
Agreement to be executed for the benefit of the Company, which obligations
remain in full force and effect, and agree to execute and adhere to the
obligations set forth in the enclosed Non-Competition and Non-Solicitation
Agreement, each of which is a condition to your employment with the Company.

 

  9. At-Will Employment. This letter shall not be construed as an agreement,
either express or implied, to employ you for any stated term, and shall in no
way alter the Company’s policy of employment at-will, under which both the
Company and you remain free to end the employment relationship for any reason,
at any time, with or without cause or notice. Similarly, nothing in this letter
shall be construed as an agreement, either express or implied, to pay you any
compensation or grant you any benefit beyond the end of your employment with the
Company, except as otherwise explicitly set forth herein. This letter supersedes
all prior understandings, whether written or oral, relating to the terms of your
employment.

 

  10. Severance Benefits. In recognition of your position with and value to the
Company, and to provide you with assurance in the event of certain employment
terminations, you have been selected to participate in the Company’s Executive
Severance and Change in Control Plan, a copy of which is enclosed with this
letter.

If this letter correctly sets forth the terms under which you will be employed
by the Company, please sign and return to me, no later than January 29, 2015,
the enclosed duplicate of this letter and the Non-Competition and
Non-Solicitation Agreement.

 

Sincerely, By:

/s/ Robert J. Gould

Robert J. Gould President & Chief Executive Officer

The foregoing correctly sets forth the terms of my at-will employment with
Epizyme, Inc. I am not relying on any representations other than those set forth
above.

 

/s/ Andrew E. Singer

1/28/15

Andrew Singer Date

 

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