EXHIBIT 10.31
CURIS, INC.
AMENDED AND RESTATED 2010 EMPLOYEE STOCK PURCHASE PLAN
The following constitute the provisions of the Amended and Restated 2010
Employee Stock Purchase Plan of Curis, Inc.

1.Purpose. The purpose of the Plan is to provide eligible employees of the
Company and its Designated Subsidiaries with opportunities to purchase shares of
Common Stock through accumulated payroll deductions. It is the intention of the
Company to have the Plan qualify as an “employee stock purchase plan” under
Section 423 of the Code and the regulations promulgated thereunder. The
provisions of the Plan, accordingly, shall be construed consistent therewith.

2.Definitions.
(a)
“Acquisition Price” shall have the meaning given such term in Section 18(b)(2)
of the Plan.

(b)
“Board” shall mean the Board of Directors of the Company.

(c)
“Code” shall mean the Internal Revenue Code of 1986, as amended.

(d)
“Committee” shall have the meaning given such term in Section 13 of the Plan.

(e)
“Common Stock” shall mean the common stock, par value $0.01, of the Company.

(f)
“Company” shall mean Curis, Inc.

(g)
“Compensation” shall mean the amount of money reportable on the employee’s
Federal Income Tax Withholding Statement, excluding overtime, shift premium,
incentive or bonus awards, allowances and reimbursements for expenses such as
relocation allowances for travel expenses, income or gains associated with the
grant or vesting of restricted stock, income or gains on the exercise of Company
stock options or stock appreciation rights, and similar items, whether or not
shown on the employee’s Federal Income Tax Withholding Statement, but including,
in the case of salespersons, sales commissions to the extent determined by the
Board.

(h)
“Designated Subsidiaries” shall mean the Subsidiaries which have been designated
by the Board from time to time in its sole discretion as eligible to participate
in the Plan.

(i)
“Enrollment Date” shall mean the first day of each Offering Period.

(j)
“Exercise Date” shall mean the last day of each Purchase Period.

(k)
“Fair Market Value” shall mean, as of any date, (a) the closing price (for the
primary trading session) on any national securities exchange on which the Common
Stock is listed, (b) the closing price of the Common Stock on the Nasdaq
National Market or (c) the average of the closing bid and asked prices in the
over-the-counter-market, whichever is applicable, as published in The Wall
Street Journal. If no sales of Common Stock were made on such a day, the price
of the Common Stock for purposes of clause (a), (b) and (c) above shall be the
reported price for the next preceding day on which sales were made.

(l)
“Offering Period” shall mean the period of approximately twenty-four (24) months
during which an option granted pursuant to the Plan may be exercised, commencing
on the first Trading Day on or after June 15 and December 15 of each year and
terminating on the last Trading Day in the period ending twenty-four (24) months
later. The duration and timing of an Offering Period may be changed pursuant to
Section 4 of this Plan.

(m)
“Option Shares” shall have the meaning given such term in Section 7 of the Plan.

(n)
“Participant” shall have the meaning given such term in Section 5(a) of the
Plan.

(o)
“Plan” shall mean this Amended and Restated 2010 Employee Stock Purchase Plan.

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(p)
“Purchase Period” shall mean the period commencing the day after an Exercise
Date and ending on the Trading Day closest to the day that is six (6) months
after the preceding Exercise Date, except that the first Purchase Period of any
Offering Period shall commence on the Enrollment Date and end with the Trading
Day that is six (6) months after the Enrollment Date. The duration and timing of
Purchase Periods may be changed pursuant to Section 4 of the Plan.

(q)
“Purchase Price” shall mean, unless the Board determines otherwise, an amount
equal to 85% of the Fair Market Value of a share of Common Stock on the
Enrollment Date or on the Exercise Date, whichever is lower.

(r)
“Reorganization Event” shall have the meaning given such term in
Section 18(b)(i) of the Plan.

(s)
“Subsidiary” shall mean any present or future subsidiary corporation as defined
in Section 424(f) of the Code.

(t)
“Trading Day” shall mean a day on which national stock exchanges and the Nasdaq
System are open for trading.

3.Eligibility.
(a)
All employees of the Company, including directors who are employees, and all
employees of any Designated Subsidiary are eligible to participate in any one or
more of the offerings to purchase Common Stock under the Plan provided that:

(i)
they are customarily employed by the Company or a Designated Subsidiary for more
than 20 hours a week and for more than five months in a calendar year; and

(ii)
they have been employed by the Company or a Designated Subsidiary for at least
six months prior to enrolling in the Plan; and

(iii)
they are employees of the Company or a Designated Subsidiary on the on a given
Enrollment Date.

(b)
Any provisions of the Plan to the contrary notwithstanding, no employee shall be
granted an option under the Plan (i) to the extent that, immediately after the
grant, such employee (or any other person whose stock would be attributed to
such employee pursuant to Section 424(d) of the Code) would own capital stock of
the Company or of any Subsidiary and/or hold outstanding options to purchase
such stock possessing five percent (5%) or more of the total combined voting
power or value of all classes of the capital stock of the Company or of any
Subsidiary, or (ii) to the extent that his or her rights to purchase stock under
all employee stock purchase plans of the Company and its Subsidiaries accrues at
a rate which exceeds Twenty-Five Thousand Dollars ($25,000) worth of stock
(determined at the Fair Market Value of the shares at the time such option is
granted) for each calendar year in which such option is outstanding at any time.
In the event that an employee may not be granted an option under the Plan
because of the foregoing restrictions, the employee shall be granted an option
to purchase the maximum number of shares that would not violate the foregoing
restrictions.

(c)
The Company retains the discretion to determine which eligible employees may
participate in an offering pursuant to and consistent with Treasury Regulation
Sections 1.423-2(e) and (f).

4.Offering Periods. The Plan shall be implemented by consecutive, overlapping
Offering Periods with a new Offering Period commencing on the first Trading Day
on or after June 15 and December 15 each year, or on such other date as the
Board shall determine, and continuing thereafter until terminated in accordance
with Section 19 hereof. The Board shall have the power to change the duration

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of Offering Periods and Purchase Periods (including the commencement dates
thereof) with respect to future offerings without stockholder approval.

5.Participation.
(a)
An eligible employee may become a participant in the Plan (a “Participant”) by
completing a payroll deduction authorization form in the form designated by the
Company from time to time and filing it at least fifteen (15) days prior to the
applicable Enrollment Date with the Company’s payroll office or such other
office as the Company may direct.

(b)
The payroll deduction authorization form will authorize a regular payroll
deduction from the Compensation received by the employee during the Offering
Period. Payroll deductions for a Participant shall commence on the first payroll
following the Enrollment Date and shall end on the last payroll in the Offering
Period to which such authorization is applicable, unless sooner terminated by
the Participant as provided in Section 10 hereof.

6.Payroll Deductions.
(a)
At the time a Participant files his or her payroll deduction authorization form,
he or she shall elect to have payroll deductions made on each pay day during the
Offering Period in an amount not exceeding fifteen percent (15%) of the
Compensation which he or she receives on each pay day during the Offering
Period. Such payroll deductions shall be in whole percentages only. The Board
may, at its discretion, designate a lower maximum contribution rate. Payroll
deductions may be at a rate of between 1% and 15% of Compensation with any
change in Compensation during the Offering Period to result in an automatic
corresponding change in the dollar amount withheld. The minimum payroll
deduction is such percentage of Compensation as may be established from time to
time by the Board.

(b)
All payroll deductions made for a Participant shall be credited to his or her
account under the Plan. A Participant may not make any additional payments into
such account.

(c)
A Participant may increase, decrease or discontinue his or her payroll deduction
during any Offering Period, by filing a new payroll deduction authorization
form. The Board may, in its discretion, limit the number of participation rate
changes during any Offering Period. If a Participant elects to discontinue
payroll deductions during an Offering Period, but does not elect to withdraw his
or her funds pursuant to Section 10, funds deducted prior to such election to
discontinue will be applied to the purchase of Common Stock on the next
occurring Exercise Date. A Participant’s payroll deduction authorization form
shall remain in effect for successive Offering Periods unless terminated as
provided in Section 10 hereof.

(d)
At the time the option (as described in Section 7) is exercised, in whole or in
part, or at the time any of the Common Stock issued under the Plan is disposed
of, the Participant must make adequate provision for the Company’s federal,
state, or other tax withholding obligations, if any, which arise upon the
exercise of the option or the disposition of the Common Stock. At any time, the
Company may, but shall not be obligated to, withhold from the Participant’s
compensation the amount necessary for the Company to meet applicable withholding
obligations, including any withholding required to make available to the Company
any tax deductions or benefits attributable to sale or other disposition of
Common Stock by the Participant.

7.Grant of Option.
(a)
On the Enrollment Date of each Offering Period, each eligible employee
participating in such Offering Period shall be granted an option to purchase (at
the applicable Purchase

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Price) up to a whole number of shares of the Common Stock the (“Option Shares”)
determined by dividing $50,000 by the Fair Market Value of a share of Common
Stock on the Enrollment Date (subject to any adjustment pursuant to Section 18),
and provided that such purchase shall be subject to the limitations set forth in
Sections 3(b) and 12 hereof. The option shall be exercisable as to 25% of the
Option Shares on each Exercise Date during the Offering Period. Exercise of the
option shall occur as provided in Section 8 hereof, unless the Participant has
withdrawn pursuant to Section 10 hereof. The option shall expire on the last day
of the Offering Period following the purchase of shares pursuant to Section 8.
(b)
To the extent permitted by any applicable laws, regulations, or rules of the
established stock exchange, national market system, or over-the-counter market
on which the Common Stock trades, if the Fair Market Value of the Common Stock
on the Enrollment Date of the next Offering Period is lower than the Fair Market
Value of the Common Stock on the Enrollment Date of any current Offering Period,
then all Participants in such current Offering Period shall be automatically
withdrawn from such Offering Period immediately after the exercise of their
option on the Exercise Date and shall be automatically re-enrolled in the next
Offering Period as of the first day thereof.

8.Exercise of Option.
(a)
Unless a Participant withdraws from the Plan as provided in Section 10 hereof,
his or her option for the purchase of shares shall be exercised automatically on
each Exercise Date during the Offering Period, and a number of full shares not
exceeding the number of shares as to which such Participant’s option is
exercisable on such Exercise Date shall be purchased for such Participant at the
applicable Purchase Price with the accumulated payroll deductions in his or her
account. No fractional shares shall be purchased. Any balance remaining in a
Participant’s payroll deduction account at the end of a Purchase Period will be
automatically refunded to the Participant, except that any balance which is less
than the purchase price of one share of Common Stock will be carried forward
into the Participant’s payroll deduction account for the following Purchase
Period or Offering Period, unless the employee elects not to participate in the
next Purchase Period or Offering Period, in which case the balance in the
employee’s account shall be refunded. During a Participant’s lifetime, a
Participant’s option to purchase shares hereunder is exercisable only by him or
her.

9.Delivery. Certificates representing shares of Common Stock purchased under the
Plan may be issued only in the name of the Participant, in the name of the
Participant and another person of legal age as joint tenants with rights of
survivorship, or (in the Company’s sole discretion) in the name of a brokerage
firm, bank, or other nominee holder designated by the Participant. The Company
may, in its sole discretion and in compliance with applicable laws, authorize
the use of book entry registration of shares in lieu of issuing certificates.

10.Withdrawal; Termination of Employment.
(a)
A Participant may withdraw all but not less than all the payroll deductions
credited to his or her account and not yet used to exercise his or her option
under the Plan at any time by giving written notice to the Company in the form
designated by the Company. All of the Participant’s payroll deductions credited
to his or her account shall be paid to such Participant promptly after receipt
of notice of withdrawal and such Participant’s option for the Offering Period
shall be automatically terminated, and no further payroll deductions for the
purchase of shares shall be made for such Offering Period. If a Participant
withdraws

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from an Offering Period, payroll deductions shall not resume at the beginning of
the succeeding Offering Period unless the Participant delivers to the Company a
new payroll deduction authorization form.
(b)
Upon a Participant’s ceasing to be an employee, for any reason, he or she shall
be deemed to have elected to withdraw from the Plan and the payroll deductions
credited to such Participant’s account during the Offering Period but not yet
used to exercise the option shall be returned to such Participant or, in the
case of his or her death, to the person or persons entitled thereto under
Section 14 hereof, and such Participant’s option shall be automatically
terminated. If, prior to the last day of the Offering Period, the Designated
Subsidiary by which the employee is employed shall cease to be a Subsidiary of
the Company, or if the employee is transferred to a Subsidiary of the Company
that is not a Designated Subsidiary, the employee shall be deemed to have
terminated employment for purposes of this Plan.

(c)
A Participant’s withdrawal from an Offering Period shall not have any effect
upon his or her eligibility to participate in any similar plan which may
hereafter be adopted by the Company or in succeeding Offering Periods.

11.Interest. Interest will not be paid on any Participant accounts, except to
the extent that the Board, in its sole discretion, elects to credit employee
accounts with interest at such rate as it may from time to time determine.

12.Stock.
(a)
The maximum number of shares of the Common Stock which shall be made available
for sale under the Plan shall be 10,000,000 shares, subject to adjustment as
provided in Section 18(a) hereof. If, on a given Exercise Date, the number of
shares with respect to which options are to be exercised exceeds the number of
shares then available under the Plan, the Company shall make a pro rata
allocation of the shares remaining available for purchase in as uniform a manner
as shall be practicable and as it shall determine to be equitable.

(b)
The Participant shall have no interest or voting right in shares covered by his
or her option until such option has been exercised and then only with respect to
the Option Shares actually purchased for the account of the Participant.

13.Administration.
(a)
The Plan shall be administered by the Board or a committee of members of the
Board appointed by the Board (a “Committee”). The Board or its Committee has
authority to make rules and regulations for the administration of the Plan and
its interpretation and decisions with regard thereto shall be final and
conclusive. Any reference to the authority of the Committee to act under this
Plan shall be contingent upon the Board having delegated such authority to the
Committee. All references to the Board contained herein shall also refer to its
Committee, as applicable.

(b)
Without stockholder consent and without regard to whether any Participant rights
may be considered to have been “adversely affected,” the Board shall be entitled
to change the Offering Periods and Purchase Periods, limit the frequency and/or
number of changes in the amount withheld during an Offering Period, establish
the exchange ratio applicable to amounts withheld in a currency other than U.S.
dollars, permit payroll withholding in excess of the amount designated by a
Participant in order to adjust for delays or mistakes in the Company’s
processing of properly completed withholding elections, establish reasonable
waiting and adjustment periods and/or accounting and crediting procedures to

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ensure that amounts applied toward the purchase of Common Stock for each
Participant properly correspond with amounts withheld from the Participant’s
Compensation and establish such other limitations or procedures as the Board
determines in its sole discretion advisable which are consistent with the Plan.

14.Designation of Beneficiary.
(a)
A Participant may file a written designation of a beneficiary who is to receive
any shares and cash, if any, from the Participant’s account under the Plan in
the event of such Participant’s death subsequent to an Exercise Date on which
the option is exercised but prior to delivery to such Participant of such shares
and cash. In addition, a Participant may file a written designation of a
beneficiary who is to receive any cash from the Participant’s account under the
Plan in the event of such Participant’s death prior to exercise of the option.
If a Participant is married and the designated beneficiary is not the spouse,
spousal consent shall be required for such designation to be effective.

(b)
Such designation of beneficiary may be changed by the Participant at any time by
written notice. In the event of the death of a Participant and in the absence of
a beneficiary validly designated under the Plan who is living at the time of
such Participant’s death, the Company shall deliver such shares and/or cash to
the executor or administrator of the estate of the Participant, or if no such
executor or administrator has been appointed (to the knowledge of the Company),
the Company, in its discretion, may deliver such shares and/or cash to the
spouse or to any one or more dependents or relatives of the Participant, or if
no spouse, dependent or relative is known to the Company, then to such other
person as the Company may designate.

15.Transferability. Neither payroll deductions credited to a Participant’s
account nor any rights with regard to the exercise of an option or to receive
shares under the Plan may be assigned, transferred, pledged or otherwise
disposed of in any way (other than by will, the laws of descent and distribution
or as provided in Section 14 hereof) by the Participant. Any such attempt at
assignment, transfer, pledge or other disposition shall be without effect,
except that the Company may treat such act as an election to withdraw funds from
an Offering Period in accordance with Section 10 hereof.

16.Use of Funds. All payroll deductions received or held by the Company under
the Plan may be used by the Company for any corporate purpose, and the Company
shall not be obligated to segregate such payroll deductions.

17.Reports. Individual accounts shall be maintained for each Participant in the
Plan in the form and on the basis determined by the Company.

18.Adjustments for Changes in Common Stock and Certain Other Events.
(a)
Changes in Capitalization. In the event of any stock split, reverse stock split,
stock dividend, recapitalization, combination of shares, reclassification of
shares, spin-off or other similar change in capitalization or event, or
distribution to holders of Common Stock other than an ordinary cash dividend,
(i) the number and class of securities available under this Plan, (ii) the share
limitations set forth in Sections 3 and 7, and (iii) the Purchase Price shall be
equitably adjusted to the extent determined by the Board.

(b)Reorganization Events.
(i)
Definition. A “Reorganization Event” shall mean: (A) any merger or consolidation
of the Company with or into another entity as a result of which all of the
Common Stock of the Company is converted into or exchanged for the right to
receive cash,

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securities or other property or is cancelled, (B) any transfer or disposition of
all of the Common Stock for cash, securities or other property pursuant to a
share exchange or other transaction or (C) any liquidation or dissolution of the
Company.
(ii)
Consequences of a Reorganization Event on Options. In connection with a
Reorganization Event, the Board may take any one or more of the following
actions as to outstanding options on such terms as the Board determines:
(A) provide that options shall be assumed, or substantially equivalent options
shall be substituted, by the acquiring or succeeding corporation (or an
affiliate thereof), (B) upon written notice to Participants, provide that all
outstanding options will be terminated immediately prior to the consummation of
such Reorganization Event and that all such outstanding options will become
exercisable to the extent of accumulated payroll deductions as of a date
specified by the Board in such notice, which date shall not be less than ten
(10) days preceding the effective date of the Reorganization Event, (C) upon
written notice to Participants, provide that all outstanding options will be
cancelled as of a date prior to the effective date of the Reorganization Event
and that all accumulated payroll deductions will be returned to participating
employees on such date, (D) in the event of a Reorganization Event under the
terms of which holders of Common Stock will receive upon consummation thereof a
cash payment for each share surrendered in the Reorganization Event (the
“Acquisition Price”), change the last day of the Offering Period to be the date
of the consummation of the Reorganization Event and make or provide for a cash
payment to each employee equal to (1) (i) the Acquisition Price times (ii) the
number of shares of Common Stock that the Participant’s accumulated payroll
deductions as of immediately prior to the Reorganization Event could purchase at
the Purchase Price, where the Acquisition Price is treated as the fair market
value of the Common Stock on the last day of the applicable Plan Period for
purposes of determining the Purchase Price under Section 2(r) hereof, and where
the number of shares that could be purchased is subject to the limitations set
forth in Sections 3 and 7, minus (2) the result of multiplying such number of
shares by such Purchase Price, (E) provide that, in connection with a
liquidation or dissolution of the Company, options shall convert into the right
to receive liquidation proceeds (net of the Purchase Price thereof) and (vi) any
combination of the foregoing.

(iii)
For purposes of clause (b)(ii)(A) above, an option shall be considered assumed
if, following consummation of the Reorganization Event, the replacement option
confers the right to purchase, for each share of Common Stock subject to the
option immediately prior to the consummation of the Reorganization Event, the
consideration (whether cash, securities or other property) received as a result
of the Reorganization Event by holders of Common Stock for each share of Common
Stock held immediately prior to the consummation of the Reorganization Event
(and if holders were offered a choice of consideration, the type of
consideration chosen by the holders of a majority of the outstanding shares of
Common Stock); provided, however, that if the consideration received as a result
of the Reorganization Event is not solely common stock of the acquiring or
succeeding corporation (or an affiliate thereof), the Company may, with the
consent of the acquiring or succeeding corporation, provide for the
consideration to be received upon the exercise of options to consist solely of
such number of shares of common stock of the acquiring or succeeding corporation
(or an affiliate thereof) that the Board determines to be equivalent in value
(as of the date of such determination or

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another date specified by the Board) to the per share consideration received by
holders of outstanding shares of Common Stock as a result of the Reorganization
Event.
 
19.Amendment or Termination. The Board may at any time, and from time to time,
amend or suspend this Plan or any portion thereof, except that (i) if the
approval of any such amendment by the shareholders of the Company is required by
Section 423 of the Code, such amendment shall not be effected without such
approval, and (ii) in no event may any amendment be made which would cause the
Plan to fail to comply with Section 423 of the Code. This Plan may be terminated
at any time by the Board. Upon termination of the Plan all amounts in the
accounts of Participants shall be promptly refunded.

20.Notices. All notices or other communications by a Participant to the Company
under or in connection with the Plan shall be deemed to have been duly given
when received in the form specified by the Company at the location, or by the
person, designated by the Company for the receipt thereof.

21.Conditions Upon Issuance of Shares. Shares shall not be issued with respect
to an option unless the exercise of such option and the issuance and delivery of
such shares pursuant thereto shall comply with all applicable provisions of law,
domestic or foreign, including, without limitation, the Securities Act of 1933,
as amended, the Securities Exchange Act of 1934, as amended, the rules and
regulations promulgated thereunder, and the requirements of any stock exchange
upon which the shares may then be listed, and shall be further subject to the
approval of counsel for the Company with respect to such compliance. As a
condition to the exercise of an option, the Company may require the person
exercising such option to represent and warrant at the time of any such exercise
that the shares are being purchased only for investment and without any present
intention to sell or distribute such shares if, in the opinion of counsel for
the Company, such a representation is required by any of the aforementioned
applicable provisions of law.

22.Effective Date. The Plan shall become effective upon, and the first Offering
Period hereunder shall begin on, June 15, 2017, subject to the Plan’s earlier
adoption by the Board and approval by the shareholders of the Company as
required by Section 423 of the Code.

23.Governmental Regulations. The Company’s obligation to sell and deliver Common
Stock under this Plan is subject to listing on an established stock exchange or
quotation on a national market system or an over the counter market (to the
extent the Common Stock is then so listed or quoted) and the approval of all
governmental authorities required in connection with the authorization,
issuance, or sale of such stock.

24.Governing Law. The Plan shall be governed by the laws of the Commonwealth of
Massachusetts except to the extent that such law is preempted by federal law.

25.Source of Shares. Shares may be issued upon exercise of an option from
authorized but unissued Common Stock, from shares held in the treasury of the
Company, or from any other proper source.

26.Notification Upon Sale of Shares. Each employee agrees, by participating in
the Plan, to promptly give notice to the Company of any disposition of shares
purchased under the Plan where such disposition occurs within two years after
the Enrollment Date with respect to the

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option pursuant to which such shares were purchased or within one year of the
date of exercise of such option pursuant to which such shares were purchased.

27.Grants to Employees in Foreign Jurisdictions. The Company may, to comply with
the laws of a foreign jurisdiction, grant options to employees of the Company or
a Designated Subsidiary who are citizens or residents of such foreign
jurisdiction (without regard to whether they are also citizens of the United
States or resident aliens (within the meaning of Section 7701(b)(1)(A) of the
Code)) with terms that are less favorable (but not more favorable) than the
terms of options granted under the Plan to employees of the Company or a
Designated Subsidiary who are resident in the United States. Notwithstanding the
preceding provisions of this Plan, employees of the Company or a Designated
Subsidiary who are citizens or residents of a foreign jurisdiction (without
regard to whether they are also citizens of the United States or resident aliens
(within the meaning of Section 7701(b)(1)(A) of the Code)) may be excluded from
eligibility under the Plan if (a) the grant of an option under the Plan to a
citizen or resident of the foreign jurisdiction is prohibited under the laws of
such jurisdiction or (b) compliance with the laws of the foreign jurisdiction
would cause the Plan to violate the requirements of Section 423 of the Code. The
Company may add one or more appendices to this Plan describing the operation of
the Plan in those foreign jurisdictions in which employees are excluded from
participation or granted less favorable options.

28.Authorization of Sub-Plans. The Board may from time to time establish one or
more sub-plans under the Plan with respect to one or more Designated
Subsidiaries, provided that such sub-plan complies with Section 423 of the Code.
 
 
 
 
 
 
Adopted by the Board of Directors
 
 
on April 6, 2010
 
 
 
 
Approved by the stockholders on
 
 
June 3, 2010

Amended and Restated by the Board of Directors on March 27, 2017

Approved by the stockholders on May 16, 2017

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AMENDMENT NO. 1 TO
CURIS, INC.
AMENDED AND RESTATED 2010 EMPLOYEE STOCK PURCHASE PLAN

This Amendment No. 1 (the “Amendment”) is made to the Amended and Restated 2010
Employee Stock Purchase Plan (the “ESPP”) of Curis, Inc. (the “Company”), which
was adopted by the Board of Directors of the Company on March 27, 2017 and
approved by its stockholders on May 16, 2017.

1.
Section 3(b) of the ESPP is amended and restated in its entirety to read as
follows:

Any provisions of the Plan to the contrary notwithstanding, no employee shall be
granted an option under the Plan to the extent that, immediately after the
grant, such employee (or any other person whose stock would be attributed to
such employee pursuant to Section 424(d) of the Code) would own capital stock of
the Company or of any Subsidiary and/or hold outstanding options to purchase
such stock possessing five percent (5%) or more of the total combined voting
power or value of all classes of the capital stock of the Company or of any
Subsidiary. In the event that an employee may not be granted an option under the
Plan because of the foregoing restriction, the employee shall be granted an
option to purchase the maximum number of shares that would not violate the
foregoing restriction.

2.
Section 7(a) of the ESPP is amended and restated in its entirety to read as
follows:

On the Enrollment Date of each Offering Period, each eligible employee
participating in such Offering Period shall be granted an option to purchase (at
the applicable Purchase Price) up to a whole number of shares of the Common
Stock the (“Option Shares”) determined by dividing $100,000 by the Fair Market
Value of a share of Common Stock on the Enrollment Date (subject to any
adjustment pursuant to Section 18), provided that such purchase shall be subject
to the limitation set forth in Section 12 hereof. The option shall be
exercisable as to 25% of the Option Shares on each Exercise Date during the
Offering Period. Any provisions of the Plan to the contrary notwithstanding,
subject to Section 423(b)(8) of the Code, no eligible employee will be permitted
to purchase stock under all employee stock purchase plans of the Company and its
Subsidiaries at a rate that exceeds Twenty-Five Thousand Dollars ($25,000) worth
of stock (determined at the Fair Market Value of the shares at the time the
option is granted) for each calendar year in which any option granted to the
eligible employee under such an employee stock purchase plan is outstanding at
any time. Exercise of the option shall occur as provided in Section 8 hereof,
unless the Participant has withdrawn pursuant to Section 10 hereof. The option
shall expire on the last day of the Offering Period following the purchase of
shares pursuant to Section 8.

Except as herein provided, all other terms and conditions of the ESPP remain
unchanged and in full force and effect. Capitalized terms used herein and not
otherwise defined herein shall have the respective meanings assigned to them in
the ESPP.

This Amendment was adopted by the Board of Directors of the Company on December
12, 2017.