Exhibit 10.21 LEASE AGREEMENT THIS
LEASE AGREEMENT (this Lease) is made as of this 22nd day of December 2017, between ARE-MA REGION NO. 59, LLC,a Delaware limited liability company (Landlord), and
SOLID BIOSCIENCES, LLC,a Delaware limited liability company (Tenant). BASIC LEASE PROVISIONS  Address of Building:

Building 1400, One Kendall Square, Cambridge, MA 02139 Premises:

That portion of the Building in the Project (as defined below) commonly known as Suite 14-101 located on the first floor of the Building, containing approximately 9,489 rentable square feet,
as shown on Exhibit A.Building:

The building in the Project currently known and numbered as 1400, One Kendall Square, Cambridge, Massachusetts, and located on the real property owned by Landlord and described on Exhibit B(the
Property).Project:

The project commonly known as One Kendall Square, located on the Property and property owned by affiliates of Landlord and operated as a single mixed-use complex.Base Rent:

$75.00 per rentable square foot of the Premises per year, subject to adjustment as provided in Section4 below. Rentable Area of Premises:9,489 rentable square feet Rentable Area of Project: 644,771 rentable square feet Rentable Area of Building: 133,989 rentable square feet Buildings Share of Project:20.78% Tenants Share:7.08% Security Deposit:$237,225.00 Target Commencement Date:February 1, 2018 Rent Commencement Date:As defined in Section2 below.  Rent Adjustment Percentage:

3%Base Term:

Beginning on the Commencement Date and ending 60 months from the first day of the first full month following the Rent Commencement Date, or if the Rent Commencement Date occurs on the first day of a month, from the first day of the
month containing the Rent Commencement Date.Permitted Use:

Research and development laboratory, related office and other related uses consistent with the character of the Project and otherwise in compliance with the provisions of Section7 hereof.  LOGO

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 2  Address for Rent Payment:

Landlords Notice Address:ARE-MA Region No. 59, LLC

385 East Colorado Boulevard, Suite 299P.O. Box 944193

Pasadena, CA91101Cleveland, OH 44194-4193

Attention: Corporate SecretaryTenants Notice Address:One Kendall Square, Building 1400Suite 14-101Cambridge, MA 02139 Attention: Lease Administrator The following Exhibits and Addenda are attached hereto and incorporated herein by this reference:  [X] EXHIBIT A- PREMISES DESCRIPTION

[X] EXHIBIT B- DESCRIPTION OF PROPERTY[X] EXHIBIT C- WORK LETTER

[X] EXHIBIT D- COMMENCEMENT DATE[X] EXHIBIT E- RULES AND REGULATIONS

[X] EXHIBIT F- TENANTS PERSONAL PROPERTY[X] EXHIBITG - NOTIFICATION OF PRESENCEOF ASBESTOS CONTAINING MATERIALS 1. Lease of Premises.Upon and subject to all of the terms and conditions of this Lease, Landlord hereby
leases the Premises to Tenant and Tenant hereby leases the Premises from Landlord. The portions of the Project which are for the non-exclusive use of tenants of the Building are collectively referred to herein
as the Common Areas.Subject to the terms and conditions of this Lease, Tenant shall have the appurtenant right to use the Common Areas for their intended uses. The Common Areas shall include, without limitation, the common
loading areas located in and serving the Building, pedestrian sidewalks and landscaped areas serving the Project, as well as the common elevators, lobbies, hallways, corridors and stairwells and, if applicable, restrooms, within the Building and
serving the Premises or necessary for access to and use of the Premises. In addition to other rights reserved herein or by law, Landlord reserves the right from time to time, without material interruption of Tenants use and access to the
Premises (except in emergency): (i) to make additions to or reconstructions of the Building, Property and Project and to install, use, maintain, repair, replace and relocate for service to the Premises or other parts of the Building, Property and/or
Project, pipes, ducts, conduits, wires and appurtenant fixtures, wherever located in the Premises, the Building, the Property or elsewhere in the Project, including without limitation, the installation of such facilities in the plenums of the
ceilings of the Premises (or, if there is no drop ceiling, within the space above 10 feet of any floor of the Premises), and coring therefor between the ceiling or top surface of any portion of the Premises, and the space above the Premises in the
plenum or below the top of the Premises as aforesaid; and (ii) to alter or relocate any Common Area or facility. From and after the
Commencement Date through the expiration of the Term, Tenant shall have access to the Building and the Premises 24 hours a day, 7 days a week, except in the case of emergencies, as the result of Legal Requirements, the performance by Landlord of any
installation, maintenance or repairs, or any other temporary interruptions, and otherwise subject to the terms of this Lease. 2.
Delivery; Acceptance of Premises; Commencement Date.Landlord shall use reasonable efforts to make the Premises available to Tenant for Tenants work on the Tenant Improvements under the Work Letter (Delivery or
Deliver) on or before the Target Commencement Date. If Landlord fails to timely Deliver the Premises, Landlord shall not be liable to Tenant for any loss or damage resulting therefrom, and this Lease shall not be void or voidable
except as provided herein. If Landlord does not Deliver the Premises within 60 days of the Target Commencement Date for any reason other than delays due to Force Majeure (as defined in Section34 below), this Lease may be
terminated by Tenant by written notice to Landlord, and if so terminated by Tenant: (a) the Security Deposit, or any balance thereof (i.e., after deducting therefrom all amounts to which Landlord is entitled under the provisions of this Lease),
shall be returned to Tenant; and (b) neither Landlord nor Tenant shall have any further rights, duties or obligations under this Lease, except with respect to provisions which expressly survive termination of this Lease. As used herein, the
term Tenant Improvementsshall have the meaning set forth for such term in the Work Letter. If Tenant does not elect to void this Lease within 10 business days of the lapse of such 60 day period, such right to void this Lease
shall be waived and this Lease shall remain in full force and effect.  LOGO

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 3  The Commencement Date shall be the date Landlord Delivers the Premises to
Tenant. The Rent Commencement Date shall be the earlier of (i) 5 months after the Commencement Date, or (ii) the date Tenant conducts any business in the Premises or any part thereof (not including the construction of the
Tenant Improvements in the Premises). Upon request of Landlord, Tenant shall execute and deliver a written acknowledgment of the Commencement Date, the Rent Commencement Date and the expiration date of the Term when such are established in the form
of the Acknowledgement of Commencement Date attached to this Lease as Exhibit D; provided, however, the failure by either party to execute and deliver such acknowledgment shall not affect either partys rights
or the Commencement Date hereunder. The Term of this Lease shall be the Base Term, as defined above in the Basic Lease Provisions and the Extension Term which Tenant may elect pursuant to Section39
hereof. For the period of 30 consecutive days after the Commencement Date, Landlord shall, at its sole cost and expense (which shall not
constitute an Operating Expense), be responsible for any repairs that are required to be made to the Building or Building Systems (as defined in Section13) serving the Premises, unless Tenant or any Tenant Party was
responsible for the cause of such repair, in which case Tenant shall pay the cost. Except as set forth in the Work Letter:
(i) Tenant shall accept the Premises in their condition as of the Commencement Date, subject to all applicable Legal Requirements (as defined in Section7 hereof); (ii) except as provided in the immediately preceding
paragraph, Landlord shall have no obligation for any defects in the Premises; and (iii) Tenants taking possession of the Premises shall be conclusive evidence that Tenant accepts the Premises and that the Premises were in good condition
at the time possession was taken. Any occupancy of the Premises by Tenant before the Commencement Date shall be subject to all of the terms and conditions of this Lease, excluding the obligation to pay Base Rent and Operating Expenses. Notwithstanding anything to the contrary contained in this Lease, Tenant and Landlord acknowledge and agree that the effectiveness of this
Lease shall be subject to the following condition precedent (Condition Precedent) having been satisfied: Landlord shall have entered into a lease termination agreement on or before January 30, 2018 (Termination
Agreement) with the existing tenant of the Premises which Termination Agreement shall be on terms and conditions acceptable to Landlord, in Landlords sole and absolute discretion. In the event that the Condition Precedent is not
satisfied, either Landlord or Tenant shall have the right to terminate this Lease upon delivery of written notice to the other. Landlord shall have no liability whatsoever to Tenant relating to or arising from Landlords inability or failure to
cause the Condition Precedent to be satisfied. Tenant agrees and acknowledges that neither Landlord nor any agent of Landlord has made
any representation or warranty with respect to the condition of all or any portion of the Premises or the Project, and/or the suitability of the Premises or the Project for the conduct of Tenants business, and Tenant waives any implied
warranty that the Premises or the Project are suitable for the Permitted Use. This Lease constitutes the complete agreement of Landlord and Tenant with respect to the subject matter hereof and supersedes any and all prior representations,
inducements, promises, agreements, understandings and negotiations which are not contained herein. Landlord in executing this Lease does so in reliance upon Tenants representations, warranties, acknowledgments and agreements contained herein. 3. Rent. (a)
Base Rent.The first full calendar months Base Rent and the Security Deposit shall be due and payable on delivery of an executed copy of this Lease to Landlord. Tenant shall pay to Landlord in advance, without demand, abatement,
deduction or set-off, equal monthly installments of Base Rent on or before the first day of each calendar month during the Term hereof from and after the Rent Commencement Date, in lawful money of the United
States of America, at the office of Landlord for payment  LOGO

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 4  of Rent set forth above, or to such other person or at such other place as Landlord may from time to time designate in writing. Payments of Base Rent for any fractional calendar month shall be
prorated. If the Rent Commencement Date is other than the first day of a calendar month, the difference between the first full calendar months Base Rent paid upon delivery of an executed copy of this Lease by Tenant to Landlord as required
above, and the prorated Base Rent for the fractional month in which the Rent Commencement Date occurs, shall be applied by Landlord to such first full calendar month after the Rent Commencement Date and Tenant shall pay the remainder of the first
full calendar months rent to Landlord on or before the first day of such first full calendar month. The obligation of Tenant to pay Base Rent, Additional Rent and any other sums to Landlord and the obligations of Landlord under this Lease are
independent obligations. Tenant shall have no right at any time to abate, reduce, or set-off any Rent (as defined in Section5) due hereunder except for any abatement as may be
expressly provided in this Lease. (b) Additional Rent. Additional Rent.In addition to Base Rent, Tenant agrees to pay to Landlord
as additional rent (Additional Rent):(i) commencing on the Rent Commencement Date, Tenants Share of Operating Expenses (as defined in Section5), and (ii) any and all other amounts
Tenant assumes or agrees to pay under the provisions of this Lease, including, without limitation, any and all other sums that may become due by reason of any default of Tenant or failure to comply with the agreements, terms, covenants and
conditions of this Lease to be performed by Tenant, after any applicable notice and cure period. 4. Base Rent Adjustments.Base
Rent shall be increased on each annual anniversary of the first day of the first full month during the Term of this Lease (each an Adjustment Date) by multiplying the Base Rent payable immediately before such Adjustment Date by
the Rent Adjustment Percentage and adding the resulting amount to the Base Rent payable immediately before such Adjustment Date. Base Rent, as so adjusted, shall thereafter be due as provided herein. Base Rent adjustments for any fractional calendar
month shall be prorated. 5. Operating Expense Payments.At least 30 days prior to the beginning of each calendar year, Landlord
shall deliver to Tenant a written estimate of Operating Expenses for the upcoming calendar year during the Term (the Annual Estimate), which may be revised by Landlord from time to time during such calendar year. Commencing on the
Rent Commencement Date and continuing thereafter on the first day of each month during the Term, Tenant shall pay Landlord an amount equal to 1/12th of Tenants Share of the Annual Estimate. Payments for any fractional calendar month shall be
prorated. The term Operating Expenses means all costs and expenses of any kind or description whatsoever incurred or
accrued each calendar year by Landlord in accordance with Landlords (and Landlords affiliates) regular accounting practices with respect to the Building and Property (including, without duplication, the Buildings Share of Project
with respect to all costs and expenses of any kind or description incurred or accrued by Landlord with respect to the Project which are not specific to the Building or Property or any other building or property located in the Project) including,
without duplication or limitation, (w) Taxes (as defined in Section9), (x) capital repairs, replacements and improvements amortized over the lesser of 10 years or the useful life of such capital items (except for
capital repairs, replacements and improvements to the roof, which shall be amortized over 15 years), adjusted to reflect Building operations 24 hours per day, 7 days per week and 365 days per year (provided that those Operating Expenses incurred or
accrued by Landlord with respect to any capital repairs, replacements or improvements which are for the intended purpose of promoting sustainability (for example, without limitation, by reducing energy usage at the Project) (a Capital
Sustainability Expenditure) may be amortized over a shorter period, at Landlords discretion, to the extent the cost of a Capital Sustainability Expenditure is offset by a reduction in Operating Expenses), (y) transportation services,
and (z) the costs of Landlords third party property manager (not to exceed 3% of Base Rent) or, if there is no third party property manager, administration rent in the amount of 3% of Base Rent, excluding only: (a) the original construction costs of the Project and renovation prior to the date of the Lease and costs of correcting defects in such
original construction or renovation;  LOGO

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 5  (b) capital expenditures for expansion of the Project; (c) interest, principal payments of Mortgage (as defined in Section27) debts of Landlord, financing costs and
amortization of funds borrowed by Landlord, whether secured or unsecured and all payments of base rent (but not taxes or operating expenses) under any ground lease or other underlying lease of all or any portion of the Project; (d) depreciation of the Project (except for capital improvements, the costs of which are includable in Operating Expenses); (e) advertising, legal and space planning expenses and leasing commissions and other costs and expenses incurred in procuring and leasing
space to tenants for the Project, including any leasing office maintained in the Project, free rent and construction allowances for tenants; (f) legal and other expenses incurred in the negotiation or enforcement of leases; (g) completing, permitting, fixturing, improving, renovating, painting, redecorating or other work, which Landlord pays for or performs for
other tenants within their premises, and costs of correcting defects in such work; (h) costs to be reimbursed by other tenants of the
Project or Taxes to be paid directly by Tenant or other tenants of the Project, whether or not actually paid; (i) salaries, wages,
benefits and other compensation paid to officers and employees of Landlord who are not assigned in whole or in part to the operation, management, maintenance or repair of the Project; provided, however, that with respect to any such person who does
not devote substantially all of his or her employed time to the Project, the salaries, wages, benefits and other compensation of such person shall be prorated to reflect time spent on matters related to operating, managing, maintaining or repairing
the Project in comparison to the time spent on matters unrelated to operating, managing, maintaining or repairing the Project; (j)
general organizational, administrative and overhead costs relating to maintaining Landlords existence, either as a corporation, partnership, or other entity, including general corporate, legal and accounting expenses; (k) costs (including attorneys fees and costs of settlement, judgments and payments in lieu thereof) incurred in connection with
disputes with tenants, other occupants, or prospective tenants, and costs and expenses, including legal fees, incurred in connection with negotiations or disputes with employees, consultants, management agents, leasing agents, purchasers or
mortgagees of the Building or Property; (l) costs incurred by Landlord due to the violation by Landlord, its employees, agents or
contractors or any tenant of the terms and conditions of any lease of space in the Project or any Legal Requirement (as defined in Section7); (m) penalties, fines or interest incurred as a result of Landlords inability or failure to make payment of Taxes and/or to file any tax
or informational returns when due, or from Landlords failure to make any payment of Taxes required to be made by Landlord hereunder before delinquency; (n) overhead and profit increment paid to Landlord or to subsidiaries or affiliates of Landlord for goods and/or services in or to the Project
to the extent the same exceeds the costs of such goods and/or services rendered by unaffiliated third parties on a competitive basis;  LOGO

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 6  (o) costs of Landlords charitable or political contributions, or of fine art maintained
at the Project; (p) costs in connection with services (including electricity), items or other benefits of a type which are not standard
for the Project and which are not available to Tenant without specific charges therefor, but which are provided to another tenant or occupant of the Project, whether or not such other tenant or occupant is specifically charged therefor by Landlord; (q) costs incurred in the sale or refinancing of the Property or Project; (r) net income taxes of Landlord or the owner of any interest in the Property or Project, franchise, capital stock, gift, estate or
inheritance taxes or any federal, state or local documentary taxes imposed against the Property or Project or any portion thereof or interest therein; (s) any expenses otherwise includable within Operating Expenses to the extent actually reimbursed by insurance policies required to be
maintained by Landlord in accordance with Section 17 (or, if Landlord fails to maintain the insurance required to be carried by Landlord pursuant to Section17, would have been reimbursed by insurance required
to be carried by Landlord pursuant to Section17); (t) any costs incurred to remove, study, test or remediate
Hazardous Materials in or about the Premises, the Building or the Project for which Tenant is not responsible under Section30 hereof; (u) any expenses otherwise includable within Operating Expenses to the extent actually reimbursed by persons other than tenants of the Project
under leases for space in the Project. Within 90 days after the end of each calendar year (or such longer period as may be reasonably
required), Landlord shall furnish to Tenant a statement (an Annual Statement) showing in reasonable detail: (a) the total and Tenants Share of actual Operating Expenses for the previous calendar year, and (b) the
total of Tenants payments in respect of Operating Expenses for such year. If Tenants Share of actual Operating Expenses for such year exceeds Tenants payments of Operating Expenses for such year, the excess shall be due and payable
by Tenant as Rent within 30 days after delivery of such Annual Statement to Tenant. If Tenants payments of Operating Expenses for such year exceed Tenants Share of actual Operating Expenses for such year Landlord shall pay the excess to
Tenant within 30 days after delivery of such Annual Statement, except that after the expiration, or earlier termination of the Term or if Tenant is delinquent in its obligation to pay Rent, Landlord shall pay the excess to Tenant after deducting all
other amounts due Landlord. Landlords and Tenants obligations to pay any overpayments or deficiencies pursuant to this paragraph shall survive the expiration or earlier termination of this Lease. The Annual Statement shall be final and binding upon Tenant unless Tenant, within 90 days after Tenants receipt thereof, shall contest
any item therein by giving written notice to Landlord, specifying each item contested and the reason therefor. If, during such 90 day period, Tenant reasonably and in good faith questions or contests the accuracy of Landlords statement of
Tenants Share of Operating Expenses, Landlord will provide Tenant with access to Landlords books and records in connection with the operation of the Project and such information in connection with the operation of the Project as Landlord
reasonably determines to be responsive to Tenants questions (the Expense Information). If after Tenants review of such Expense Information, Landlord and Tenant cannot agree upon the amount of Tenants Share of
Operating Expenses, then Tenant shall have the right to have a regionally recognized independent public accounting firm selected by Tenant and approved by Landlord (which approval shall not be unreasonably withheld, conditioned or delayed), working
pursuant to a fee arrangement other than a contingent fee (at Tenants sole cost and expense), audit and/or review the Expense Information for the year in question (the Independent Review). The results of any such Independent
Review shall be binding on Landlord and Tenant. If the Independent Review shows that Tenants actual payments with respect to the Operating Expenses for the calendar year in question exceeded Tenants Share of Operating Expenses for such
calendar year, Landlord shall at Landlords option either (i) credit the excess amount to the next succeeding installments of estimated Operating Expenses or (ii) pay the excess to Tenant within 30 days after delivery  LOGO

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 7  of such statement, except that after the expiration, or earlier termination of this Lease or if Tenant is delinquent in its obligation to pay Rent, Landlord shall pay the excess to Tenant after
deducting all other amounts due Landlord. If the Independent Review shows that Tenants payments with respect to Operating Expenses for such calendar year were less than Tenants Share of Operating Expenses for the calendar year, Tenant
shall pay the deficiency to Landlord within 30 days after delivery of such statement. If the Independent Review shows that Tenant has overpaid Tenants Share of Operating Expenses by more than 5% then Landlord shall reimburse Tenant for all
costs incurred by Tenant for the Independent Review. Operating Expenses for the calendar years in which Tenants obligation to share therein begins and ends shall be prorated. Notwithstanding anything set forth herein to the contrary, if the
Building is not at least 95% occupied on average during any year of the Term, Tenants Share of Operating Expenses for such year shall be computed as though the Building had been 95% occupied on average during such year. Tenants Share shall be the percentage set forth in the Basic Lease Provisions as Tenants Share, and
Buildings Share of Project shall be the percentage set forth in the Basic Lease Provisions as the Buildings Share of Project, each as may be reasonably adjusted by Landlord upon a measurement of the rentable square
footage of the Premises, Building, Property and/or Project done by Landlord, if Landlord so elects, within 90 days of the Commencement Date, or as soon as reasonably possible thereafter, and shall be subject to further adjustment for changes in the
physical size of the Premises, Building, Property or Project occurring thereafter. Landlord may equitably increase Tenants Share for any item of expense or cost reimbursable by Tenant that relates to a repair, replacement, or service that
benefits only the Premises or only a portion of the Building, Property or Project that includes the Premises or that varies with occupancy or use. Landlord may equitably increase the Buildings Share of Project for any item of expense or cost
reimbursable by Tenant that relates to a repair, replacement, or service that benefits only the Building or only a portion of the Property or Project that includes the Building or that varies with occupancy or use of the Building. Base Rent,
Tenants Share of Operating Expenses and all other amounts payable by Tenant to Landlord hereunder are collectively referred to herein as Rent. 6. Security Deposit. Tenant shall deposit with Landlord, upon delivery of an executed copy of this Lease to Landlord, a security
deposit (the Security Deposit) for the performance of all of Tenants obligations hereunder in the amount set forth in the Basic Lease Provisions, which Security Deposit shall be in the form of an unconditional and
irrevocable letter of credit (the Letter of Credit): (i) in form and substance reasonably satisfactory to Landlord, (ii) naming Landlord as beneficiary, (iii) expressly allowing Landlord to draw upon it at any time from
time to time by delivering to the issuer notice that Landlord is entitled to draw thereunder, (iv) issued by an FDIC-insured financial institution satisfactory to Landlord, and (v) redeemable by presentation of a sight draft in the state
of Landlords choice. If Tenant does not provide Landlord with a substitute Letter of Credit complying with all of the requirements hereof at least 10 days before the stated expiration date of any then current Letter of Credit, Landlord shall
have the right to draw the full amount of the current Letter of Credit and hold the funds drawn in cash without obligation for interest thereon as the Security Deposit. The Security Deposit shall be held by Landlord as security for the performance
of Tenants obligations under this Lease. The Security Deposit is not an advance rental deposit or a measure of Landlords damages in case of Tenants default. Upon each occurrence of a Default (as defined in
Section20), Landlord may use all or any part of the Security Deposit to pay delinquent payments due under this Lease, and the cost of any damage, injury, expense or liability caused by such Default, without prejudice to
any other remedy provided herein or provided by law. Upon any such use of all or any portion of the Security Deposit, Tenant shall pay Landlord on demand the amount that will restore the Security Deposit to the amount set forth in the Basic Lease
Provisions. Tenant hereby waives the provisions of any law, now or hereafter in force, which provide that Landlord may claim from a security deposit only those sums reasonably necessary to remedy defaults in the payment of Rent, to repair damage
caused by Tenant or to clean the Premises, it being agreed that Landlord may, in addition, claim those sums reasonably necessary to compensate Landlord for any other loss or damage, foreseeable or unforeseeable, caused by the act or omission of
Tenant or any officer, employee, agent or invitee of Tenant. Upon bankruptcy or other debtor-creditor proceedings against Tenant, the Security Deposit shall be deemed to be applied first to the payment of Rent and other charges due Landlord for
periods prior to the filing of such proceedings. Upon any such use of all or any portion of the Security Deposit, Tenant shall, within 10 days after demand from Landlord, restore the Security Deposit to its original amount. If Tenant  LOGO

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 8  shall fully perform every provision of this Lease to be performed by Tenant, the Security Deposit, or any balance thereof (i.e., after deducting therefrom all amounts to which Landlord is
entitled under the provisions of this Lease), shall be returned to Tenant (or, at Landlords option, to the last assignee of Tenants interest hereunder) within 60 days after the expiration or earlier termination of this Lease. If Landlord transfers its interest in the Project or this Lease, Landlord shall either (a) transfer any Security Deposit then held by
Landlord to a person or entity assuming Landlords obligations under this Section6, or (b) return to Tenant any Security Deposit then held by Landlord and remaining after the deductions permitted herein. Upon
such transfer to such transferee or the return of the Security Deposit to Tenant, Landlord shall have no further obligation with respect to the Security Deposit, and Tenants right to the return of the Security Deposit shall apply solely
against Landlords transferee. The Security Deposit is not an advance rental deposit or a measure of Landlords damages in case of Tenants default. Landlords obligation respecting the Security Deposit is that of a debtor, not a
trustee, and no interest shall accrue thereon. 7. Use. (a) Tenants Use. The Premises shall be used solely for the Permitted Use set forth in the Basic Lease Provisions, and in
compliance with all laws, orders, judgments, ordinances, regulations, codes, directives, permits, licenses, covenants and restrictions now or hereafter applicable to the Premises, and to the use and occupancy thereof, including, without limitation,
the Americans With Disabilities Act, 42 U.S.C. § 12101, et seq. (together with the regulations promulgated pursuant thereto, ADA) (collectively, Legal Requirements and each, a Legal
Requirement). Tenant shall, upon 5 days written notice from Landlord, discontinue any use of the Premises which is declared by any Governmental Authority (as defined in Section9) having jurisdiction to be a
violation of a Legal Requirement. Tenant will not use or permit the Premises to be used for any purpose or in any manner that would void Tenants or Landlords insurance, increase the insurance risk, or cause the disallowance of any
sprinkler or other credits. Tenant shall not permit any part of the Premises to be used as a place of public accommodation, as defined in the ADA or any similar legal requirement. Tenant shall reimburse Landlord promptly upon demand for
any additional premium charged for any such insurance policy by reason of Tenants failure to comply with the provisions of this Section or otherwise caused by Tenants use and/or occupancy of the Premises. Tenant will use the Premises in
a careful, safe and proper manner and will not commit or permit waste, overload the floor or structure of the Premises, subject the Premises to use that would damage the Premises or obstruct or interfere with the rights of Landlord or other tenants
or occupants of the Project, including conducting or giving notice of any auction, liquidation, or going out of business sale on the Premises, or using or allowing the Premises to be used for any unlawful purpose. Tenant shall cause any equipment or
machinery to be installed in the Premises so as to reasonably prevent sounds or vibrations from the Premises from extending into Common Areas, or other space in the Project. Tenant shall not place any machinery or equipment weighing 500 pounds or
more in or upon the Premises or transport or move such items through the Common Areas of the Building or in the Building elevators without the prior written consent of Landlord. Except as may be provided under the Work Letter, Tenant shall not,
without the prior written consent of Landlord, use the Premises in any manner which will require ventilation, air exchange, heating, gas, steam, electricity or water beyond the existing capacity of the Building as proportionately allocated to the
Premises based upon Tenants Share as usually furnished for the Permitted Use. Landlord shall be responsible for the compliance of
the Common Areas of the Project with Legal Requirements as of the Commencement Date. Following the Commencement Date, Landlord shall, as an Operating Expense (to the extent such Legal Requirement is generally applicable to similar buildings in the
area in which the Project is located) and at Tenants expense (to the extent such Legal Requirement is triggered by reason of Tenants, as compared to other tenants of the Project, specific use or occupancy of the Premises or Tenants
Alterations) make any alterations or modifications to the Common Areas or the exterior of the Building (including structural obligations or modifications) that are required by Legal Requirements. Except as provided in the two immediately preceding
sentences, Tenant, at its sole expense, shall make any alterations or modifications to the interior of the Premises that are required by Legal Requirements (including, without limitation, compliance of the Premises with the ADA) related to  LOGO

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 9  Tenants specific use or occupancy of the Premises, the Tenant Improvements or Tenants Alterations. Notwithstanding any other provision herein to the contrary, Tenant shall be
responsible for any and all demands, claims, liabilities, losses, costs, expenses, actions, causes of action, damages or judgments, and all reasonable expenses incurred in investigating or resisting the same (including, without limitation,
reasonable attorneys fees, charges and disbursements and costs of suit) (collectively, Claims) arising out of or in connection with Legal Requirements related to Tenants specific use or occupancy of the Premises, the
Tenant Improvements or Tenants Alterations, and Tenant shall indemnify, defend, hold and save Landlord harmless from and against any and all Claims arising out of or in connection with any failure of the Premises to comply with any Legal
Requirement related to Tenants specific use or occupancy of the Premises, the Tenant Improvements or any Tenant Alterations. (b)
Energy Use Reporting. Tenant agrees to provide, within 10 business days of request by Landlord, such information and documentation as may be needed for compliance with the City of Cambridge Building Energy Use Disclosure Ordinance,
Section 8.67.010 et seq. of the Municipal Code of the City of Cambridge (as the same may be amended, the Cambridge Building Energy Use Disclosure Ordinance), and other such energy or sustainability requirements as may be
adopted from time to time by the City of Cambridge or any other governmental authority with jurisdiction over the Building, which information shall include without limitation usage at or by the Premises of electricity, natural gas, steam, hot or
chilled water or other energy. Landlord shall report to the applicable governmental authority such energy usage for the Building and other Building information as required by the Cambridge Building Energy Use Disclosure Ordinance. 8. Holding Over. If, with Landlords express written consent, Tenant retains possession of the Premises after the termination of
the Term, (i) unless otherwise agreed in such written consent, such possession shall be subject to immediate termination by Landlord at any time, (ii) all of the other terms and provisions of this Lease (including, without limitation, the
adjustment of Base Rent pursuant to Section4 hereof) shall remain in full force and effect (excluding any expansion or renewal option or other similar right or option) during such holdover period, (iii) Tenant shall
continue to pay Base Rent in the amount payable upon the date of the expiration or earlier termination of this Lease or such other amount as Landlord may indicate, in Landlords sole and absolute discretion, in such written consent, and
(iv) all other payments shall continue under the terms of this Lease. If Tenant remains in possession of the Premises after the expiration or earlier termination of the Term without the express written consent of Landlord, (A) Tenant shall
become a tenant at sufferance upon the terms of this Lease except that the monthly rental shall be equal to 150% of Rent in effect during the last 30 days of the Term, and (B) Tenant shall be responsible for all damages suffered by Landlord
resulting from or occasioned by Tenants holding over, including consequential damages; provided, however, that if Tenant delivers a written inquiry to Landlord within 30 days prior to the expiration or earlier termination of the Term, Landlord
will notify Tenant whether the potential exists for consequential damages. No holding over by Tenant, whether with or without consent of Landlord, shall operate to extend this Lease except as otherwise expressly provided, and this
Section8 shall not be construed as consent for Tenant to retain possession of the Premises. Acceptance by Landlord of Rent after the expiration of the Term or earlier termination of this Lease shall not result in a renewal
or reinstatement of this Lease. 9. Taxes. Landlord shall pay, as part of Operating Expenses, all taxes, levies, fees, assessments
and governmental charges of any kind, existing as of the Commencement Date or thereafter enacted (collectively referred to as Taxes), imposed by any federal, state, regional, municipal, local or other governmental authority or
agency, including, without limitation, quasi-public agencies (collectively, Governmental Authority) during the Term, including, without limitation, all Taxes: (i) imposed on or measured by or based, in whole or in part, on
rent payable to (or gross receipts received by) Landlord under this Lease and/or from the rental by Landlord of the Building, Property or Project or any portion thereof, or (ii) based on the square footage, assessed value or other measure or
evaluation of any kind of the Premises, Building, Property or Project or portion thereof, or (iii) assessed or imposed by or on the operation or maintenance of any portion of the Premises, Building, Property or Project, including parking, or
(iv) assessed or imposed by, or at the direction of, or resulting from Legal Requirements, or interpretations thereof, promulgated by, any Governmental Authority, or (v) imposed as a license or other fee, charge, tax  LOGO

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 10  or assessment on Landlords business or occupation of leasing space in the Building, Property or Project or portion thereof. Landlord may contest by appropriate legal proceedings the amount,
validity, or application of any Taxes or liens securing Taxes. Taxes shall not include any net income taxes imposed on Landlord except to the extent such net income taxes are in substitution for any Taxes payable hereunder. If any such Tax is levied
or assessed directly against Tenant, then Tenant shall be responsible for and shall pay the same at such times and in such manner as the taxing authority shall require. Operating Expenses hereunder shall also include the cost of tax monitoring
services provided to Landlord with respect to the Building, Property or Project. Tenant shall pay, prior to delinquency, any and all Taxes levied or assessed against any personal property or trade fixtures placed by Tenant in the Premises, whether
levied or assessed against Landlord or Tenant. If any Taxes on Tenants personal property or trade fixtures are levied against Landlord or Landlords property, or if the assessed valuation of the Building, Property or Project is increased
by a value attributable to improvements in or alterations to the Premises, whether owned by Landlord or Tenant and whether or not affixed to the real property so as to become a part thereof, higher than the base valuation on which Landlord from time-to-time allocates Taxes to all tenants in the Building, Property or Project, or portion thereof of which the Premises are a part, Landlord shall have the right, but not
the obligation, to pay such Taxes. Landlords reasonable determination of any excess assessed valuation shall be binding and conclusive, absent manifest error. The amount of any such payment by Landlord shall constitute Additional Rent due from
Tenant to Landlord immediately upon demand. 10. Parking and PTDM. (a) Parking and Monthly Parking Charge. Subject to all matters of record, Force Majeure, a Taking (as defined in
Section19 below), the exercise by Landlord of its rights hereunder and upon payment of the Monthly Parking Charge (as defined below) for each parking space commencing on the Rent Commencement Date, Tenant shall have the
right, in common with other tenants of the Project to use 1.0 vehicle parking spaces per 1,000 rentable square feet of the Premises (Tenants Parking Allowance) in the parking facility located at the One Kendall Square Garage
located on Binney Street (the OKS Garage) to park in those areas designated for non-reserved parking, subject in each case to Landlords reasonable rules and regulations; provided,
however, Landlord may relocate any or all of Tenants Parking Allowance from the OKS Garage to another parking facility in close proximity to the OKS Garage (i.e., being within 0.25 miles of the OKS Garage). If, during the Term, Tenant delivers
written notice to Landlord requesting additional parking spaces and Landlord determines that the additional parking spaces desired by Tenant are available for use by Tenant, Landlord shall notify Tenant in writing and Tenant shall commence using and
paying the Monthly Parking Charge for such additional parking spaces immediately following Landlords delivery of such written notice to Tenant that such additional parking spaces are available for Tenants use. Landlord shall not be
responsible for enforcing Tenants parking rights against any third parties, including other tenants of the Project. The Monthly Parking Charge shall mean the market rate monthly charge therefor designated by Landlord,
adjusted reasonably and no more frequently than once in any 12-month period, based upon the rates charged by comparable parking facilities in the vicinity of the Project, which as of the date of this Lease
such Monthly Parking Charge is equal to $325.00 per space per month, plus applicable taxes. (b) Parking and Transportation Demand
Management. Tenant shall, at Tenants sole expense, for so long as a parking and traffic demand management plan approved by the City of Cambridge (as amended from time to time, the PTDM), is applicable to the Project,
comply with the PTDM as applicable to the Project, including without limitation, as applicable (i) offer to subsidize mass transit monthly passes for all of its employees who work in the Premises in accordance with the terms set forth in the
PTDM; (ii) implement a Commuter Choice Program and the MBTAs Corporate Pass Plan; (iii) discourage single-occupant vehicle (SOV) use by its employees; (iv) promote alternative modes of transportation and use
of alternative work hours; (v) at Landlords request, meet with Landlord and/or its representatives no more frequently than quarterly to discuss transportation programs and initiatives; (vi) participate in annual surveys, monitoring
transportation programs and initiatives at the Campus, and, without limitation, achieve a sixty (60%) percent response rate for patron surveys; (vii) cooperate with Landlord in connection with transportation programs and initiatives promulgated
pursuant to the PTDM;  LOGO

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 11  (viii) provide alternative work programs (such as telecommuting, flex-time and compressed work weeks) to its employees in order to reduce traffic impacts in Cambridge during peak commuter hours;
(ix) offer an emergency ride home (ERH) through the Charles River Transportation Management Association (CRTMA), or have its own ERH program, for all employees who commute by
non-SOV mode at least 3 days a week and who are eligible to park in the parking spaces in the parking facility described above; (x) cooperate with the Cambridge Office of Workforce Development to expand
employment opportunities for Cambridge residents; (xi) become a member of the CRTMA and cause the EZ Ride shuttle service to service the Building; (xii) in the event that the single occupancy vehicle and traffic generation modal split
limits of the PTDM are exceeded, charge each user of a parking space the market rate for parking in Kendall Square/East Cambridge therefor; (xiii) comply with the requirements of any other parking and traffic demand management plan to which
Tenant may be a party from time to time; (xiii) designate an employee transportation coordinator for the Building; and (xiv) otherwise cooperate with Landlord in encouraging employees to seek alternate modes of transportation. 11. Utilities, Services. Landlord shall provide, subject to the terms of this Section11, water, electricity,
heat, light, power, sewer, and other utilities (including gas and fire sprinklers to the extent the Building is plumbed for such services), and refuse and trash collection and janitorial services (collectively, Utilities).
Landlord shall pay, as Operating Expenses or subject to Tenants reimbursement obligation, for all Utilities used on the Premises, all maintenance charges for Utilities, and any storm sewer charges or other similar charges for Utilities imposed
by any Governmental Authority or Utility provider, and any taxes, penalties, surcharges or similar charges thereon. The Premises shall be separately metered to measure Tenants usage of electricity for lights and plugs. Landlord may cause, at
Tenants expense, any Utilities to be separately metered or charged directly to Tenant by the provider. Tenant shall pay directly to the Utility provider, prior to delinquency, any separately metered Utilities and services which may be
furnished to Tenant or the Premises during the Term. Tenant shall pay, as part of Operating Expenses, its share of all charges for jointly metered Utilities based upon consumption, as reasonably determined by Landlord. No interruption or failure of
Utilities, from any cause whatsoever, shall result in eviction or constructive eviction of Tenant, termination of this Lease or, except as otherwise expressly provided in the immediately following paragraph, the abatement of Rent. Tenant agrees to
limit use of water and sewer with respect to Common Areas to normal restroom use. Notwithstanding anything to the contrary set forth
herein, if (i) a stoppage of an Essential Service (as defined below) to the Premises shall occur and such stoppage is due solely to the gross negligence or willful misconduct of Landlord and not due in any part to any act or omission on the
part of Tenant or any Tenant Party or any matter beyond Landlords reasonable control (any such stoppage of an Essential Service being hereinafter referred to as a Service Interruption), and (ii) such Service
Interruption continues for more than 3 consecutive business days after Landlord shall have received written notice thereof from Tenant, and (iii) as a result of such Service Interruption, the conduct of Tenants normal operations in the
Premises are materially and adversely affected, then there shall be an abatement of one days Base Rent for each day during which such Service Interruption continues after such 3 business day period; provided, however, that if any part of the
Premises is reasonably useable for Tenants normal business operations or if Tenant conducts all or any part of its operations in any portion of the Premises notwithstanding such Service Interruption, then the amount of each daily abatement of
Base Rent shall only be proportionate to the nature and extent of the interruption of Tenants normal operations or ability to use the Premises. The rights granted to Tenant under this paragraph shall be Tenants sole and exclusive remedy
resulting from a failure of Landlord to provide services, and Landlord shall not otherwise be liable for any loss or damage suffered or sustained by Tenant resulting from any failure or cessation of services. For purposes hereof, the term
Essential Services shall mean the following services: HVAC service, water, sewer and electricity, but in each case only to the extent that Landlord has an obligation to provide same to Tenant under this Lease. Landlords sole obligation for either providing emergency generators or providing emergency backup power to Tenant shall be: (i) to
provide emergency generators with not less than the capacity of the emergency generators located in the Building as of the Commencement Date, and (ii) to contract with a third party to maintain the emergency generators as per the
manufacturers standard maintenance  LOGO

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Multi-Tenant Laboratory

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 12  guidelines. Except as otherwise provided in the immediately preceding sentence, Landlord shall have no obligation to provide Tenant with operational emergency generators or back-up power or to supervise, oversee or confirm that the third party maintaining the emergency generators is maintaining the generators as per the manufacturers standard guidelines or otherwise. During any
period of replacement, repair or maintenance of the emergency generators when the emergency generators are not operational, including any delays thereto due to the inability to obtain parts or replacement equipment, Landlord shall have no obligation
to provide Tenant with an alternative back-up generator or generators or alternative sources of back-up power. Tenant acknowledges and agrees that (x) in connection
with the proper verification of loads and maintenance of the emergency generators, that power will need to be transferred during routine testing, and (y) Tenant is responsible for cooperating with Landlord or Landlords third party
contractor with respect to scheduling such routine tests and checking its own equipment loads as it operates during load transfer periods. Tenant expressly acknowledges and agrees that Landlord does not guaranty that such emergency generators will
be operational at all times or that emergency power will be available to the Premises when needed. 12. Alterations and Tenants
Property. Any alterations, additions, or improvements made to the Premises by or on behalf of Tenant, including additional locks or bolts of any kind or nature upon any doors or windows in the Premises, but excluding installation, removal or
realignment of furniture systems (other than removal of furniture systems owned or paid for by Landlord) not involving any modifications to the structure or connections (other than by ordinary plugs or jacks) to Building Systems (as defined in
Section13) (Alterations) shall be subject to Landlords prior written consent, which may be given or withheld in Landlords sole discretion if any such Alteration affects the structure or
Building Systems, but which shall otherwise not be unreasonably withheld or delayed. Tenant may construct nonstructural, cosmetic Alterations in the Premises that will not affect the operation of any Building Systems, without Landlords prior
approval if the aggregate cost of all such work in any 12 month period does not exceed $25,000.00 (excluding paint and carpet/floor coverings) (a Notice-Only Alteration), provided Tenant notifies Landlord in writing of such
intended Notice-Only Alteration, and such notice shall be accompanied by plans, specifications, work contracts and such other information concerning the nature and cost of the Notice-Only Alteration as may be reasonably requested by Landlord, which
notice and accompanying materials shall be delivered to Landlord not less than 15 business days in advance of any proposed construction. If Landlord approves any Alterations, Landlord may impose such conditions on Tenant in connection with the
commencement, performance and completion of such Alterations as Landlord may deem appropriate in Landlords reasonable discretion. Any request for approval shall be in writing, delivered not less than 15 business days in advance of any proposed
construction, and accompanied by plans, specifications, bid proposals, work contracts and such other information concerning the nature and cost of the alterations as may be reasonably requested by Landlord, including the identities and mailing
addresses of all persons performing work or supplying materials. Landlords right to review plans and specifications and to monitor construction shall be solely for its own benefit, and Landlord shall have no duty to ensure that such plans and
specifications or construction comply with applicable Legal Requirements. Tenant shall cause, at its sole cost and expense, all Alterations to comply with insurance requirements and with Legal Requirements and shall implement at its sole cost and
expense any alteration or modification required by Legal Requirements as a result of any Alterations. Tenant shall pay to Landlord, as Additional Rent, on demand an amount equal to the reasonable out-of-pocket costs incurred by Landlord for plan review, coordination, scheduling and supervision. Before Tenant begins any Alteration, Landlord may post on and about the Premises notices of non-responsibility pursuant to applicable law. Tenant shall reimburse Landlord for, and indemnify and hold Landlord harmless from, any expense incurred by Landlord by reason of faulty work done by Tenant or its
contractors, delays caused by such work, or inadequate cleanup. Tenant shall furnish security or make other arrangements satisfactory to
Landlord to assure payment for the completion of all Alterations work free and clear of liens, and shall provide (and cause each contractor or subcontractor to provide) certificates of insurance for workers compensation and other coverage in
amounts and from an insurance company reasonably satisfactory to Landlord protecting Landlord against liability for personal injury or property damage during construction. Upon completion of any Alterations, Tenant shall deliver to Landlord:
(i) sworn statements setting forth the names of all contractors and subcontractors who did the work and final lien waivers from all such contractors and subcontractors; and (ii) to the extent available, as built plans for any
such Alteration.  LOGO

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 13  Other than (i) the items, if any, listed on ExhibitF attached hereto,
(ii) any items agreed by Landlord in writing to be included on Exhibit F in the future, and (iii) any trade fixtures, machinery, equipment and other personal property not paid for out of the TI Fund (as defined in the Work Letter)
which may be removed without material damage to the Premises, which damage shall be repaired (including capping or terminating utility hook-ups behind walls) by Tenant during the Term (collectively,
Tenants Property), all property of any kind paid for with the TI Fund, all Alterations, real property fixtures, built-in machinery and equipment,
built-in casework and cabinets and other similar additions and improvements built into the Premises so as to become an integral part of the Premises, such as fume hoods which penetrate the roof or plenum area,
built-in cold rooms, built-in warm rooms, walk-in cold rooms, walk-in warm rooms,
deionized water systems, glass washing equipment, autoclaves, chillers, built-in plumbing, electrical and mechanical equipment and systems, and any power generator and transfer switch (collectively,
Installations) shall be and shall remain the property of Landlord during the Term and following the expiration or earlier termination of the Term, shall not be removed by Tenant at any time during the Term and shall remain upon
and be surrendered with the Premises as a part thereof in accordance with Section28 following the expiration or earlier termination of this Lease; provided, however, that Landlord shall, at the time its
approval of such Installation is requested notify Tenant if it has elected to cause Tenant to remove such Installation upon the expiration or earlier termination of this Lease. If Landlord so elects, Tenant shall remove such Installation upon the
expiration or earlier termination of this Lease and restore any damage caused by or occasioned as a result of such removal, including, when removing any of Tenants Property which was plumbed, wired or otherwise connected to any of the Building
Systems, capping off all such connections behind the walls of the Premises and repairing any holes. During any such restoration period, Tenant shall pay Rent to Landlord as provided herein as if said space were otherwise occupied by Tenant. 13. Landlords Repairs. Landlord, as an Operating Expense, shall maintain all of the structural, exterior, parking and other
Common Areas of the Building and Property, including HVAC, plumbing, fire sprinklers, elevators and all other building systems serving the Premises and other portions of the Building (Building Systems), in good repair, reasonable
wear and tear and uninsured losses and damages caused by Tenant, or by any of Tenants agents, servants, employees, invitees and contractors (collectively, Tenant Parties) excluded. Losses and damages caused by Tenant or any
Tenant Party shall be repaired by Landlord, to the extent not covered by insurance, at Tenants sole cost and expense. Landlord reserves the right to stop Building Systems services when necessary (i) by reason of accident or emergency, or
(ii) for planned repairs, alterations or improvements, which are, in the judgment of Landlord, desirable or necessary to be made, until said repairs, alterations or improvements shall have been completed. Landlord shall have no responsibility
or liability for failure to supply Building Systems services during any such period of interruption; provided, however, that Landlord shall, except in case of emergency, make a commercially reasonable effort to give Tenant 24 hours
advance notice of any planned stoppage of Building Systems services for routine maintenance, repairs, alterations or improvements. Landlord shall use reasonable efforts to minimize interference with Tenants operations in the Premises during
such planned stoppages of Building Systems. Tenant shall promptly give Landlord written notice of any repair required by Landlord pursuant to this Section (or with respect to any emergency, oral notice followed immediately by written notice), after
which Landlord shall have a reasonable opportunity to effect such repair. Landlord shall not be liable for any failure to make any repairs or to perform any maintenance unless such failure shall persist for an unreasonable time after Tenants
written notice of the need for such repairs or maintenance. Tenant waives its rights under any state or local law to terminate this Lease or to make such repairs at Landlords expense and agrees that the parties respective rights with
respect to such matters shall be solely as set forth herein. Repairs required as the result of fire, earthquake, flood, vandalism, war, or similar cause of damage or destruction shall be controlled by Section18. 14. Tenants Repairs. Subject to Section13 hereof, Tenant, at its expense, shall repair, replace and
maintain in good condition all portions of the Premises, including, without limitation, entries, doors, ceilings, interior windows, interior walls, and the interior side of demising walls, reasonable wear and tear and damage by fire or other
casualty excepted. Should Tenant fail to make any such repair or  LOGO

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 14  replacement or fail to maintain the Premises, Landlord shall give Tenant notice of such failure. If Tenant fails to commence cure of such failure within 30 days of Landlords notice, and
thereafter diligently prosecute such cure to completion, Landlord may perform such work and shall be reimbursed by Tenant within 30 days after demand therefor; provided, however, that if such failure by Tenant creates or could create an emergency,
Landlord may immediately commence cure of such failure and shall thereafter be entitled to recover the costs of such cure from Tenant. Subject to Sections 17 and 18, Tenant shall bear the full uninsured cost of any repair or
replacement to any part of the Project that results from damage caused by Tenant or any Tenant Party and any repair that benefits only the Premises. 15. Mechanics Liens. Tenant shall discharge, by bond or otherwise, any mechanics lien filed against the Premises or against
the Building, Property or Project for work claimed to have been done for, or materials claimed to have been furnished to, Tenant within 20 days after Tenant receives notice of the filing thereof, at Tenants sole cost and shall otherwise keep
the Premises and the Building, Property and Project free from any liens arising out of work performed, materials furnished or obligations incurred by Tenant. Should Tenant fail to discharge any lien described herein, Landlord shall have the right,
but not the obligation, to pay such claim or post a bond or otherwise provide security to eliminate the lien as a claim against title to the Building, Property or Project and the cost thereof shall be immediately due from Tenant as Additional Rent.
If Tenant shall lease or finance the acquisition of office equipment, furnishings, or other personal property of a removable nature utilized by Tenant in the operation of Tenants business, Tenant warrants that any Uniform Commercial Code
Financing Statement filed as a matter of public record by any lessor or creditor of Tenant will upon its face or by exhibit thereto indicate that such Financing Statement is applicable only to removable personal property of Tenant located within the
Premises. In no event shall the address of the Building or Project be furnished on the statement without qualifying language as to applicability of the lien only to removable personal property, located in an identified suite held by Tenant. 16. Indemnification. Tenant hereby indemnifies and agrees to defend, save and hold Landlord, its officers, directors, employees,
managers, agents, sub-agents, constituent entities and lease signators (collectively, Landlord Indemnified Parties) and Holders of Mortgages (each as defined in
Section27 below) as to which Tenant has been given notice harmless from and against any and all Claims for injury or death to persons or damage to property occurring within or about the Premises, arising directly or
indirectly out of the use or occupancy of the Premises by Tenant or any Tenant Parties or a breach or default by Tenant in the performance of any of its obligations hereunder, except to the extent caused by the willful misconduct or negligence of
Landlord Indemnified Parties. Landlord Indemnified Parties shall not be liable to Tenant for, and Tenant assumes all risk of damage to, personal property (including, without limitation, loss of records kept within the Premises). Tenant further
hereby irrevocably waives any and all Claims for injury to Tenants business or loss of income relating to any such damage or destruction of personal property (including, without limitation, any loss of records). Landlord Indemnified Parties
shall not be liable for any damages arising from any act, omission or neglect of any tenant in the Project or of any other third party. 17. Insurance. Landlord shall maintain all risk property and, if applicable, sprinkler damage insurance covering the full replacement
cost of the Building. Landlord shall further procure and maintain commercial general liability insurance with a single loss limit of not less than $2,000,000 for bodily injury and property damage with respect to the Project. Landlord may, but is not
obligated to, maintain such other insurance and additional coverages as it may deem necessary, including, but not limited to, flood, environmental hazard and earthquake, loss or failure of building equipment, errors and omissions, rental loss during
the period of repair or rebuilding, workers compensation insurance and fidelity bonds for employees employed to perform services and insurance for any improvements installed by Tenant or which are in addition to the standard improvements
customarily furnished by Landlord without regard to whether or not such are made a part of the Project. All such insurance shall be included as part of the Operating Expenses. The Building and Property may be included in a blanket policy (in which
case the cost of such insurance allocable to the Building and Property will be determined by Landlord based upon the insurers cost calculations). Tenant shall also reimburse Landlord for any increased premiums or additional insurance which
Landlord reasonably deems necessary as a result of Tenants use of the Premises.  LOGO

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 15  Tenant, at its sole cost and expense, shall maintain during the Term: all risk property
insurance with business interruption and extra expense coverage, covering the full replacement cost of all property and improvements installed or placed in the Premises by Tenant at Tenants expense; workers compensation insurance with no
less than the minimum limits required by law; employers liability insurance with such limits as required by law; and commercial general liability insurance, with a minimum limit of not less than $2,000,000 per occurrence for bodily injury and
property damage with respect to the Premises]. The commercial general liability insurance policy shall name Alexandria Real Estate Equities, Inc., and Landlord, its officers, directors, employees, managers, agents,
sub-agents, constituent entities and lease signators (collectively, Landlord Insured Parties), as additional insureds; insure on an occurrence and not a claims-made basis; be issued by
insurance companies which have a rating of not less than policyholder rating of A and financial category rating of at least Class X in Bests Insurance Guide; shall not be cancelable for nonpayment of premium unless 30 days
prior written notice shall have been given to Landlord from the insurer; not contain a hostile fire exclusion; contain a contractual liability endorsement; and provide primary coverage to Landlord Insured Parties (any policy issued to Landlord
Insured Parties providing duplicate or similar coverage shall be deemed excess over Tenants policies, regardless of limits). Certificates of insurance showing the limits of coverage required hereunder and showing Landlord as an additional
insured, along with reasonable evidence of the payment of premiums for the applicable period, shall be delivered to Landlord by Tenant upon commencement of the Term and upon each renewal of said insurance. Tenants policy may be a blanket
policy with an aggregate per location endorsement which specifically provides that the amount of insurance shall not be prejudiced by other losses covered by the policy. Tenant shall, at least 5 days prior to the expiration of such policies,
furnish Landlord with renewal certificates. In each instance where insurance is to name Landlord as an additional insured, Tenant shall
upon written request of Landlord also designate and furnish certificates so evidencing Landlord as additional insured to: (i) any lender of Landlord holding a security interest in the Building, Property or Project or any portion thereof and any
servicer in connection therewith, (ii) the landlord under any lease wherein Landlord is tenant of the real property on which the Building, Property or Project is located, if the interest of Landlord is or shall become that of a tenant under a
ground or other underlying lease rather than that of a fee owner, and/or (iii) any management company retained by Landlord to manage the Project. The property insurance obtained by Landlord and Tenant shall include a waiver of subrogation by the insurers and all rights based upon an
assignment from its insured, against Landlord or Tenant, and their respective officers, directors, employees, managers, agents, invitees and contractors (Related Parties), in connection with any loss or damage thereby insured
against. Neither party nor its respective Related Parties shall be liable to the other for loss or damage caused by any risk insured against under property insurance required to be maintained hereunder, and each party waives any claims against the
other party, and its respective Related Parties, for such loss or damage. The failure of a party to insure its property shall not void this waiver. Landlord and its respective Related Parties shall not be liable for, and Tenant hereby waives all
claims against such parties for, business interruption and losses occasioned thereby sustained by Tenant or any person claiming through Tenant resulting from any accident or occurrence in or upon the Premises, Building, Property or Project from any
cause whatsoever. If the foregoing waivers shall contravene any law with respect to exculpatory agreements, the liability of Landlord or Tenant shall be deemed not released but shall be secondary to the others insurer. Landlord may require insurance policy limits to be raised to conform with requirements of Landlords lender and/or to bring coverage
limits to levels then being generally required of new tenants within the Project; provided, however, that the increased amount of coverage is consistent with coverage amounts then being required by institutional owners of similar projects with
tenants occupying similar size premises in the geographical area in which the Project is located. 18. Restoration.If, at
any time during the Term, the Building or the Premises are damaged or destroyed by a fire or other insured casualty, Landlord shall notify Tenant within 60 days after discovery of such damage as to the amount of time Landlord reasonably estimates it
will take to restore the Building or the Premises, as applicable (the Restoration Period). If the Restoration Period is estimated to exceed  LOGO

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 16  12 months (the Maximum Restoration Period), Landlord may, in such notice, elect to terminate this Lease as of the date that is 75 days after the date of discovery of such
damage or destruction; provided, however, that notwithstanding Landlords election to restore, Tenant may elect to terminate this Lease by written notice to Landlord delivered within 5 business days of receipt of a notice from
Landlord estimating a Restoration Period for the Premises longer than the Maximum Restoration Period. Unless either Landlord or Tenant so elects to terminate this Lease, Landlord shall, subject to receipt of sufficient insurance proceeds (with any
deductible to be treated as a current Operating Expense), promptly restore the Premises (excluding the improvements installed by Tenant or by Landlord and paid for by Tenant), subject to delays arising from the collection of insurance proceeds, from
Force Majeure events or as needed to obtain any license, clearance or other authorization of any kind required to enter into and restore the Premises issued by any Governmental Authority having jurisdiction over the use, storage, handling,
treatment, generation, release, disposal, removal or remediation of Hazardous Materials (as defined in Section30) in, on or about the Premises (collectively referred to herein as Hazardous Materials
Clearances); provided, however, that if repair or restoration of the Premises is not substantially complete as of the end of the Maximum Restoration Period or, if longer, the Restoration Period, Landlord may, in its sole and
absolute discretion, elect not to proceed with such repair and restoration, or Tenant may by written notice to Landlord delivered within 5 business days of the expiration of the Maximum Restoration Period or, if longer, the Restoration Period, elect
to terminate this Lease, in which event Landlord shall be relieved of its obligation to make such repairs or restoration and this Lease shall terminate as of the date that is 75 days after the later of: (i) discovery of such damage or
destruction, or (ii) the date all required Hazardous Materials Clearances are obtained, but Landlord shall retain any Rent paid and the right to any Rent payable by Tenant prior to such election by Landlord or Tenant. Tenant, at its expense, shall promptly perform, subject to delays arising from the collection of insurance proceeds, from Force Majeure (as
defined in Section34) events or to obtain Hazardous Material Clearances, all repairs or restoration not required to be done by Landlord and shall promptly re-enter the Premises and
commence doing business in accordance with this Lease. Notwithstanding the foregoing, either Landlord or Tenant may terminate this Lease upon written notice to the other if the Premises are damaged during the last year of the Term and Landlord
reasonably estimates that it will take more than 2 months to repair such damage; provided, however, that such notice is delivered within 10 business days after the date that Landlord provides Tenant with written notice of the estimated Restoration
Period. Notwithstanding anything to the contrary contained herein, Landlord shall also have the right to terminate this Lease if insurance proceeds are not available for such restoration. Rent shall be abated from the date all required Hazardous
Material Clearances are obtained until the Premises are repaired and restored, in the proportion which the area of the Premises, if any, which is not usable by Tenant bears to the total area of the Premises, unless Landlord provides Tenant with
other space during the period of repair that is suitable for the temporary conduct of Tenants business. In the event that no Hazardous Material Clearances are required to be obtained by Tenant with respect to the Premises, rent abatement shall
commence on the date of discovery of the damage or destruction. Such abatement shall be the sole remedy of Tenant, and except as provided in this Section18, Tenant waives any right to terminate the Lease by reason of
damage or casualty loss. The provisions of this Lease, including this Section18, constitute an express
agreement between Landlord and Tenant with respect to any and all damage to, or destruction of, all or any part of the Premises, or any other portion of the Building, Property or Project, and any statute or regulation which is now or may hereafter
be in effect shall have no application to this Lease or any damage or destruction to all or any part of the Premises or any other portion of the Building, Property or Project, the parties hereto expressly agreeing that this
Section18 sets forth their entire understanding and agreement with respect to such matters. 19.
Condemnation.If the whole or any material part of the Premises, Building or Property is taken for any public or quasi-public use under governmental law, ordinance, or regulation, or by right of eminent domain, or by private purchase
in lieu thereof (a Taking or Taken), and the Taking would in Landlords reasonable judgment materially interfere with or impair Landlords ownership or operation of the Building or Property or would in
the reasonable judgment of Landlord and Tenant either prevent or  LOGO

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 17  materially interfere with Tenants use of the Premises (as resolved, if the parties are unable to agree, by arbitration by a single arbitrator with the qualifications and experience
appropriate to resolve the matter and appointed pursuant to and acting in accordance with the rules of the American Arbitration Association), then upon written notice by Landlord or Tenant to the other this Lease shall terminate and Rent shall be
apportioned as of said date. If part of the Premises shall be Taken, and this Lease is not terminated as provided above, Landlord shall promptly restore the Premises and the Building and Property as nearly as is commercially reasonable under the
circumstances to their condition prior to such partial Taking and the rentable square footage of the Building, the rentable square footage of the Premises, Tenants Share of Operating Expenses, the Buildings Share of Project and the Rent
payable hereunder during the unexpired Term shall be reduced to such extent as may be fair and reasonable under the circumstances. Upon any such Taking, Landlord shall be entitled to receive the entire price or award from any such Taking without any
payment to Tenant, and Tenant hereby assigns to Landlord Tenants interest, if any, in such award. Tenant shall have the right, to the extent that same shall not diminish Landlords award, to make a separate claim against the condemning
authority (but not Landlord) for such compensation as may be separately awarded or recoverable by Tenant for moving expenses and damage to Tenants trade fixtures, if a separate award for such items is made to Tenant. Tenant hereby waives any
and all rights it might otherwise have pursuant to any provision of state law to terminate this Lease upon a partial Taking of the Premises, Building, Property or Project. 20. Events of Default.Each of the following events shall be a substantial default (Default) by Tenant under
this Lease: (a) Payment Defaults.Tenant shall fail to pay any installment of Rent or any other payment hereunder when due;
provided, however, that Landlord will give Tenant notice and an opportunity to cure any failure to pay Rent within 5 days of any such notice not more than once in any 12 month period and Tenant agrees that such notice shall be in lieu of and not in
addition to, or shall be deemed to be, any notice required by law. (b) Insurance.Any insurance required to be maintained
by Tenant pursuant to this Lease shall be canceled or terminated or shall expire or shall be reduced or materially changed, or Landlord shall receive a notice of nonrenewal of any such insurance and Tenant shall fail to obtain replacement insurance
at least 5 days before the expiration of the current coverage. (c) Abandonment.Tenant shall abandon the Premises,
provided, however, that Tenant shall be deemed not to have abandoned the Premises if: (i) prior to vacating the Premises Tenant provides Landlord with prior notice and complies with the requirements pertaining to a Surrender Plan as set forth
in Section28, (ii) prior to or at the time of vacating the Premises, Tenant has made reasonable arrangements for the security of the Premises for the balance of the Term and notified Landlord of such arrangements,
(iii) Tenant continues to maintain in force any permits and approvals as may be required by any Governmental Authority for the Premises, and (iv) Tenant continues during the balance of the Term to satisfy all of its obligations under the
Lease as they come due, including without limitation the obligation to pay Rent. (d) Improper Transfer.Tenant shall
assign, sublease or otherwise transfer or attempt to transfer all or any portion of Tenants interest in this Lease or the Premises except as expressly permitted herein, or Tenants interest in this Lease shall be attached, executed upon,
or otherwise judicially seized and such action is not released within 90 days of the action. (e) Liens.Tenant shall fail
to discharge or otherwise obtain the release of any lien placed upon the Premises in violation of this Lease within 20 days after Tenant receives notice that a lien is filed against the Premises. (f) Insolvency Events.Tenant or any guarantor or surety of Tenants obligations hereunder shall: (A) make a general
assignment for the benefit of creditors; (B) commence any case, proceeding or other action seeking to have an order for relief entered on its behalf as a debtor or to  LOGO

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 18  adjudicate it a bankrupt or insolvent, or seeking reorganization, arrangement, adjustment, liquidation, dissolution or composition of it or its debts or seeking appointment of a receiver,
trustee, custodian or other similar official for it or for all or of any substantial part of its property (collectively a Proceeding for Relief); (C) become the subject of any Proceeding for Relief which is not dismissed within 90 days
of its filing or entry; or (D) be dissolved or otherwise fail to maintain its legal existence. (g) Estoppel Certificate or
Subordination Agreement.Tenant fails to execute any document required from Tenant under Sections 23 or 27 within 5 days after a second notice requesting such document. (h) Other Defaults.Tenant shall fail to comply with any provision of this Lease other than those specifically referred to in
this Section20, and, except as otherwise expressly provided herein, such failure shall continue for a period of 30 days after written notice thereof from Landlord to Tenant. Any notice given under Section20(h) hereof shall: (i) specify the alleged default, (ii) demand that Tenant cure such
default, (iii) be in lieu of, and not in addition to, or shall be deemed to be, any notice required under any provision of applicable law, and (iv) not be deemed a forfeiture or a termination of this Lease unless Landlord elects otherwise
in such notice; provided that if the nature of Tenants default pursuant to Section20(h) is such that it cannot be cured by the payment of money and reasonably requires more than 30 days to cure, then Tenant
shall not be deemed to be in default if Tenant commences such cure within said 30 day period and thereafter diligently prosecutes the same to completion; provided, however, that such cure shall be completed no later than 60 days from
the date of Landlords notice. 21. Landlords Remedies. (a) Payment By Landlord; Interest.Upon a Default by Tenant hereunder, Landlord may, without waiving or releasing any obligation
of Tenant hereunder, make such payment or perform such act. All sums so paid or incurred by Landlord, together with interest thereon, from the date such sums were paid or incurred, at the annual rate equal to 12% per annum or the highest rate
permitted by law (the Default Rate), whichever is less, shall be payable to Landlord on demand as Additional Rent. Nothing herein shall be construed to create or impose a duty on Landlord to mitigate any damages resulting from
Tenants Default hereunder. (b) Late Payment Rent.Late payment by Tenant to Landlord of Rent and other sums due will
cause Landlord to incur costs not contemplated by this Lease, the exact amount of which will be extremely difficult and impracticable to ascertain. Such costs include, but are not limited to, processing and accounting charges and late charges which
may be imposed on Landlord under any Mortgage covering the Premises. Therefore, if any installment of Rent due from Tenant is not received by Landlord within 5 days after the date such payment is due, Tenant shall pay to Landlord an additional sum
of 6% of the overdue Rent as a late charge. Notwithstanding the foregoing, before assessing a late charge the first time in any calendar year, Landlord shall provide Tenant written notice of the delinquency and will waive the right if Tenant pays
such delinquency within 5 days thereafter. The parties agree that this late charge represents a fair and reasonable estimate of the costs Landlord will incur by reason of late payment by Tenant. In addition to the late charge, Rent not paid when due
shall bear interest at the Default Rate from the 5th day after the date due until paid. (c) Remedies.Upon the occurrence
of a Default, Landlord, at its option, without further notice or demand to Tenant, shall have in addition to all other rights and remedies provided in this Lease, at law or in equity, the option to pursue any one or more of the following remedies,
each and all of which shall be cumulative and nonexclusive, without any notice or demand whatsoever (except as otherwise expressly provided in Section21(c)(v) with respect to Landlords Lump Sum Election). No cure in
whole or in part of such Default by Tenant after Landlord has taken any action beyond giving Tenant notice of such Default to pursue any remedy provided for herein (including retaining counsel to file an action or otherwise pursue any remedies)
shall in any way affect Landlords right to pursue such remedy or any other remedy provided Landlord herein or under law or in equity, unless Landlord, in its sole discretion, elects to waive such Default.  LOGO

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 19  (i) This Lease and the Term and estate hereby granted are subject to the
limitation that whenever a Default shall have happened and be continuing, Landlord shall have the right, at its election, then or thereafter while any such Default shall continue and notwithstanding the fact that Landlord may have some other remedy
hereunder or at law or in equity, to give Tenant written notice of Landlords intention to terminate this Lease on a date specified in such notice, which date shall be not less than 5 days after the giving of such notice, and upon the date so
specified, this Lease and the estate hereby granted shall expire and terminate with the same force and effect as if the date specified in such notice were the date hereinbefore fixed for the expiration of this Lease, and all rights of Tenant
hereunder shall expire and terminate, and Tenant shall be liable as hereinafter in this Section21(c) provided. If any such notice is given, Landlord shall have, on such date so specified, the right of re-entry and possession of the Premises and the right to remove all persons and property therefrom and to store such property in a warehouse or elsewhere at the risk and expense, and for the account, of Tenant.
Should Landlord elect to re-enter as herein provided or should Landlord take possession pursuant to legal proceedings or pursuant to any notice provided for by law, Landlord may, subject to
Section21(c)(ii) from time to time re-let the Premises or any part thereof for such term or terms and at such rental or rentals and upon such terms and conditions as Landlord may
deem advisable, with the right to make commercially reasonable alterations in and repairs to the Premises. (ii) Landlord
shall be deemed to have satisfied any obligation to mitigate its damages by hiring an experienced commercial real estate broker to market the Premises and directing such broker to advertise and show the Premises to prospective tenants. (iii) In the event of any termination of this Lease as in this Section21 provided or as required or
permitted by law or in equity, Tenant shall forthwith quit and surrender the Premises to Landlord, and Landlord may, without further notice, enter upon, re-enter, possess and repossess the same by summary
proceedings, ejectment or otherwise, and again have, repossess and enjoy the same free of any rights of Tenant, and in any such event Tenant and no person claiming through or under Tenant by virtue of any law or an order of any court shall be
entitled to possession or to remain in possession of the Premises. (iv) If this Lease is terminated or if Landlord shall re-enter the Premises as aforesaid, or in the event of the termination of this Lease, or of re-entry, by or under any proceeding or action or any provision of law by reason of
a Default by Tenant, Tenant covenants and agrees forthwith to pay and be liable for, on the days originally fixed in this Lease for the payment thereof, amounts equal to the installments of Base Rent and all Additional Rent as they would, under the
terms of this Lease become due if this Lease had not been terminated or if Landlord had not entered or re-entered, as aforesaid, and whether the Premises be relet or remain vacant, in whole or in part, or for a period less than the remainder of the
Term, or for the whole thereof, but in the event that the Premises be relet by Landlord, Tenant shall be entitled to a credit in the net amount of rent and other charges received by Landlord in reletting, after deduction of all of Landlords
reasonable expenses incurred in reletting the Premises (including, without limitation, tenant improvement, demising and remodeling costs, brokerage fees and the like), and in collecting the rent in connection therewith, in the following manner:
Amounts received by Landlord after reletting, if any, shall first be applied against such Landlords expenses, until the same are recovered, and until such recovery, Tenant shall pay, as of each day when a payment would fall due under this
Lease, the amount which Tenant is obligated to pay under the terms of this Lease (Tenants liability prior to any such reletting and such recovery by Landlord no in any way to be diminished as a result of the fact that such reletting might be
for a rent higher than the rent provided for in this Lease); when and if such expenses have been completely recovered by Landlord, the amounts received from reletting by Landlord as have not previously been applied shall be credited against
Tenants obligations as of each day when a payment would fall due under this Lease, and only the net amount thereof shall be payable by Tenant. Further, Tenant shall not be entitled to any credit of any kind for any period after the date when
the Term of this Lease is scheduled to expire according to its terms.  LOGO

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 20  Actions, proceedings or suits for the recovery of damages, whether liquidated
or other damages, under this Lease, or any installments thereof, may be brought by Landlord from time to time at its election, and nothing contained herein shall be deemed to require Landlord to postpone suit until the date when the Term of this
Lease would have expired if it had not been terminated hereunder. (v) In addition, Landlord, at its election,
notwithstanding any other provision of this Lease, by written notice to Tenant (the Lump Sum Election), shall be entitled to recover from Tenant, as and for liquidated damages, at any time following any termination of this Lease,
a lump sum payment representing, at the time of Landlords written notice of its Lump Sum Election, the sum of: (A)
the then present value (calculated in accordance with accepted financial practice using as the discount rate the yield to maturity on United States Treasury Notes as set forth below) of the amount of unpaid Base Rent and Additional Rent that would
have been payable pursuant to this Lease for the remainder of the Term following Landlords Lump Sum Election if this Lease had not been terminated, and (B) all other damages and expenses (including attorneys fees and expenses), if any, which Landlord shall have sustained
by reason of the breach of any provision of this Lease; less (C) the then present value (calculated in accordance with
accepted financial practice using as the discount rate the yield to maturity on United States Treasury Notes as set forth below) of the aggregate net fair market rent plus additional charges payable for the Premises (if less than the then present
value of Base Rent and Additional Rent that would have been payable pursuant to this Lease) for the remainder of the Term following Landlords Lump Sum Election, calculated as of the date of Landlords Lump Sum Election, and taking into
account reasonable estimates of the future costs to relet any then vacant portions of the Premises (except to the extent that Tenant has actually paid such costs pursuant to this Section21) in order to calculate the net
rental revenue that Landlord may expect to obtain for the Premises for the balance of the Term. Landlords recovery
under its Lump Sum Election shall be in addition to Tenants obligations to pay Base Rent and Additional Rent due and costs incurred prior to the date of Landlords Lump Sum Election, and in lieu of any Base Rent and Additional Rent which
would otherwise have been due under this Section from and after the date of Landlords Lump Sum Election. The yield to maturity on United States Treasury Notes having a maturity date that is nearest the date that would have been the last day of
the Term of the Lease, as reported in the Wall Street Journal or a comparable publication if it ceases to publish such yields, shall be used in calculating present values for purposes of Landlords Lump Sum Election. For the purposes of
this Section, if Landlord makes the Lump Sum Election to recover liquidated damages in accordance with this Section, the total Additional Rent shall be computed based upon Landlords reasonable estimate of Tenants Share of Operating
Expenses and other Additional Rent for each 12-month period in what would have been the remainder of the Term of the Lease and any part thereof at the end of such remainder of the Term, but in no event less
than the amounts therefor payable for the twelve (12) calendar months (or if less than twelve (12) calendar months have elapsed since the date hereof, the partial year) immediately preceding the date of Landlords Lump Sum Election.
Amounts of Tenants Share of Operating Expenses and any other Additional Rent for any partial year at the beginning of the Term or at the end of what would have been the remainder of the Term shall be prorated.  LOGO

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 21  (vi) Nothing herein contained shall limit or prejudice the right of Landlord,
in any bankruptcy or insolvency proceeding, to prove for and obtain as liquidated damages by reason of such termination an amount equal to the maximum allowed by any bankruptcy or insolvency proceedings, or to prove for and obtain as liquidated
damages by reason of such termination, an amount equal to the maximum allowed by any statute or rule of law, whether such amount shall be greater or less than the excess referred to above. (vii) Nothing in this Section21 shall be deemed to affect the right of either party to
indemnifications pursuant to this Lease. (viii) If Landlord terminates this Lease upon the occurrence of a Default, Tenant
will quit and surrender the Premises to Landlord or its agents, and Landlord may, without further notice, enter upon, re-enter and repossess the Premises by summary proceedings, ejectment or otherwise. The
words enter, re-enter, and re-entry are not restricted to their technical legal meanings. (ix) If Tenant shall be in default in the observance or performance of any provision of this Lease, and an action shall be
brought for the enforcement thereof in which it shall be determined that Tenant was in default, Tenant shall pay to Landlord all reasonable, out of pocket fees, costs and other expenses which may become payable as a result thereof or in connection
therewith, including reasonable attorneys fees and expenses. (x) If default by Tenant shall occur in the keeping,
observance or performance of any covenant, agreement, term, provision or condition herein contained, Landlord, without thereby waiving such default, may perform the same for the account and at the expense of Tenant (a) immediately or at any time
thereafter and with only such notice, if any, as may be practicable under the circumstances in the case of an emergency or in case such default will result in a violation of any legal or insurance requirements, or in the imposition of any lien
against all or any portion of the Premises or the Project not discharged, released or bonded over to Landlords satisfaction by Tenant within the time period required pursuant to Section15 of this Lease, and
(b) in any other case if such default continues after any applicable notice and cure period provided in Section 20. All reasonable costs and expenses incurred by Landlord in connection with any such performance by it for the account
of Tenant and also all reasonable costs and expenses, including attorneys fees and disbursements incurred by Landlord in any action or proceeding (including any summary dispossess proceeding) brought by Landlord to enforce any obligation of
Tenant under this Lease and/or right of Landlord in or to the Premises, shall be paid by Tenant to Landlord within 30 days after demand. (xi) Independent of the exercise of any other remedy of Landlord hereunder or under applicable law, Landlord may conduct an
environmental test of the Premises as generally described in Section30(d). (xii) In the event
that Tenant is in Default under this Lease, whether or not Landlord exercises its right to terminate or any other remedy, Tenant shall reimburse Landlord upon demand for any out of pocket costs and expenses that Landlord may incur in connection with
any such Default, as provided in this Section21(c). Such costs shall include reasonable legal fees and costs incurred for the negotiation of a settlement, enforcement of rights or otherwise. Tenant shall also indemnify
Landlord against and hold Landlord harmless from all costs, expenses, demands and liability, including without limitation, reasonable legal fees and costs Landlord shall incur if Landlord shall become or be made a party to any claim or action
instituted by Tenant against any third party, by any third party against Tenant or by or against any person holding any interest under or using the Premises by license of or agreement with Tenant.  LOGO

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 22  (xiii) Except as otherwise provided in this
Section21, no right or remedy herein conferred upon or reserved to Landlord is intended to be exclusive of any other right or remedy, and every right and remedy shall be cumulative and in addition to any other legal or
equitable right or remedy given hereunder, or now or hereafter existing. No waiver by Landlord of any provision of this Lease shall be deemed to have been made unless expressly so made in writing by Landlord expressly waiving such provision.
Landlord shall be entitled, to the extent permitted by law, to seek injunctive relief in case of the violation, or attempted or threatened violation, of any provision of this Lease, or to seek a decree compelling observance or performance of any
provision of this Lease, or to seek any other legal or equitable remedy. 22. Assignment and Subletting. (a) General Prohibition.Without Landlords prior written consent subject to and on the conditions described in this
Section22, Tenant shall not, directly or indirectly, voluntarily or by operation of law, assign this Lease or sublease the Premises or any part thereof or mortgage, pledge, or hypothecate its leasehold interest or grant
any concession or license within the Premises, and any attempt to do any of the foregoing shall be void and of no effect. If Tenant is a corporation, partnership or limited liability company, the shares or other ownership interests thereof which are
not actively traded upon a stock exchange or in the over-the-counter market, a transfer or series of transfers whereby 50% or more of the issued and outstanding shares
or other ownership interests of such corporation are, or voting control is, transferred (but excepting transfers upon deaths of individual owners) from a person or persons or entity or entities which were owners thereof at time of execution of this
Lease to persons or entities who were not owners of shares or other ownership interests of the corporation, partnership or limited liability company at time of execution of this Lease, shall be deemed an assignment of this Lease requiring the
consent of Landlord as provided in this Section22. Notwithstanding the foregoing, Tenant shall have the right to obtain financing from institutional investors (including venture capital funding and corporate partners)
which regularly invest in private biotechnology companies or undergo a public offering which results in a change in control of Tenant without such change of control constituting an assignment under this Section22 requiring
Landlord consent, provided that (i) Tenant notifies Landlord in writing of the financing at least 5 business days prior to the closing of the financing, and (ii) provided that in no event shall such financing result in a change in use of
the Premises from the use contemplated by Tenant at the commencement of the Term. (b) Permitted Transfers. (i) Permitted Transfers Generally. If Tenant desires to assign, sublease, hypothecate or otherwise transfer this Lease
or sublet the Premises, then at least 15 business days, but not more than 45 business days, before the date Tenant desires the assignment or sublease to be effective (the Assignment Date), Tenant shall give Landlord a notice (the
Assignment Notice) containing such information about the proposed assignee or sublessee, including the proposed use of the Premises and any Hazardous Materials proposed to be used, stored handled, treated, generated in or released
or disposed of from the Premises, the Assignment Date, any relationship between Tenant and the proposed assignee or sublessee, and all material terms and conditions of the proposed assignment or sublease, including a copy of any proposed assignment
or sublease in its final form, and such other information as Landlord may deem reasonably necessary or appropriate to its consideration whether to grant its consent. Landlord may, by giving written notice to Tenant within 15 business days after
receipt of the Assignment Notice: (i) grant such consent, (ii) refuse such consent, in its reasonable discretion, or (iii) with respect to any assignment or any sublease that would result in more than 50% rentable square feet of the
Premises being subleased for substantially the remaining balance of the Term, terminate this Lease with respect to the space described in the Assignment Notice as of the Assignment Date (an Assignment Termination). If Landlord
delivers notice of its election to exercise an Assignment Termination, Tenant shall have the right to withdraw such Assignment Notice by written notice to Landlord of such election within 5 business days after Landlords notice electing to
exercise the Assignment Termination. If Tenant withdraws such Assignment Notice, this Lease shall continue in full force and effect. If Tenant does not withdraw such Assignment Notice, this Lease, and the term and estate herein granted, shall
terminate as of the Assignment Date with respect to the space  LOGO

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 23  described in such Assignment Notice. No failure of Landlord to exercise any such option to terminate this Lease, or to deliver a timely notice in response to the Assignment Notice, shall be
deemed to be Landlords consent to the proposed assignment, sublease or other transfer. Tenant shall pay to Landlord a fee equal to Three Thousand Dollars ($3,000) in connection with its consideration of any Assignment Notice and/or its
preparation or review of any consent documents; provided that it shall be reasonable for Landlord to withhold its consent, among other reasons, in any of the following instances: (A) the business or financial reputation of the proposed assignee
or sublessee, or the business or financial reputation of any of the respective principals or officers thereof, is objectionable in Landlords reasonable judgment, (B) the proposed assignee or subtenant is engaged in areas of scientific
research or other business concerns that are controversial such that they may (i) attract or cause negative publicity for or about the Building or the Project, (ii) negatively affect the reputation of the Building, the Project or Landlord,
(iii) attract protestors to the Building or the Project, or (iv) lessen the attractiveness of the Building or the Project to any tenants or prospective tenants, purchasers or lenders, (C) the proposed assignee or sublessee is at that
time an occupant of the Project or negotiating with Landlord or an affiliate thereof for the lease of other space in the Project, (D) the proposed assignee or sublessee lacks the creditworthiness to support the financial obligations it would
incur under the proposed assignment or sublease, (E) the proposed assignee or sublessee is a governmental agency, (F) in Landlords reasonable judgment, the use of the Premises by the proposed assignee or sublessee would entail any
alterations that would lessen the value of the leasehold improvements in the Premises, or would require increased services by Landlord, (G) Landlord has experienced previous defaults by or is in litigation with the proposed assignee or
sublessee (H) the proposed assignment or sublease will create a vacancy elsewhere in the Project, or (I) the assignment or sublease is prohibited by Landlords lender. In any event, Landlord shall further have the right to review and
approve or disapprove the proposed form of sublease prior to the effective date of any such subletting. (ii) Affiliate
Transactions.Notwithstanding the foregoing, Landlords consent to a sublease to any entity controlling, controlled by or under common control with Tenant (each, an Affiliate and collectively
Affiliates) shall not be required, provided that Landlord shall have the right to approve the form of any such sublease, such approval not to be unreasonably withheld, conditioned or delayed. In addition, Tenant shall have the
right to assign this Lease, upon 10 days prior written notice to Landlord but without obtaining Landlords prior written consent, to an Affiliate or to a corporation or other entity which is a successor in interest to Tenant, by way of
merger, consolidation or corporate reorganization, or by the purchase of all or substantially all of the assets or the ownership interests of Tenant provided that: (A) in the case of an assignment to a successor in interest, such merger,
consolidation, reorganization or purchase, as the case may be, is for a good business purpose and not principally for the purpose of transferring the Lease; and (B) in all events the net worth (as determined in accordance with generally
accepted accounting principles (GAAP)) of the Affiliate assignee or successor in interest to Tenant is not less than the net worth (as determined in accordance with GAAP) of Tenant as of the date of Tenants most current
quarterly or annual financial statements as delivered under Section40(c) or filed with the Securities and Exchange Commission; and (C) such Affiliate assignee or successor-in-interest to Tenant shall agree in writing to assume all of the terms, covenants and conditions of this Lease (any assignment of this Lease or sublease to an Affiliate or a successor-in-interest in accordance with this paragraph is referred to herein as a Permitted Assignment). (c) Additional Conditions.As a condition to any such assignment or subletting, whether or not Landlords consent is
required, Landlord may require: (i) that any assignee or subtenant agree, in writing at the time of such assignment or
subletting, that if Landlord gives such party notice that Tenant is in default under this Lease, such party shall thereafter make all payments otherwise due Tenant directly to Landlord, which payments will be received by Landlord without any
liability except to credit such payment against those due under the Lease, and any such third party shall agree to attorn to Landlord or its successors and assigns should this Lease be terminated for any reason; provided, however, in
no event shall Landlord or its successors or assigns be obligated to accept such attornment; and  LOGO

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 24  (ii) A list of Hazardous Materials, certified by the proposed assignee or
sublessee to be true and correct, which the proposed assignee or sublessee intends to use, store, handle, treat, generate in or release or dispose of from the Premises, together with copies of all documents relating to such use, storage, handling,
treatment, generation, release or disposal of Hazardous Materials by the proposed assignee or subtenant in the Premises or on the Project, prior to the proposed assignment or subletting, including, without limitation: permits; approvals; reports and
correspondence; storage and management plans; plans relating to the installation of any storage tanks to be installed in or under the Project (provided, said installation of tanks shall only be permitted after Landlord has given its written consent
to do so, which consent may be withheld in Landlords sole and absolute discretion); and all closure plans or any other documents required by any and all federal, state and local Governmental Authorities for any storage tanks installed in, on
or under the Project for the closure of any such tanks. Neither Tenant nor any such proposed assignee or subtenant is required, however, to provide Landlord with any portion(s) of the such documents containing information of a proprietary nature
which, in and of themselves, do not contain a reference to any Hazardous Materials or hazardous activities. (d) No Release of Tenant,
Sharing of Excess Rents.Notwithstanding any assignment or subletting, Tenant and any guarantor or surety of Tenants obligations under this Lease shall at all times remain fully and primarily responsible and liable for the payment
of Rent and for compliance with all of Tenants other obligations under this Lease. If the Rent due and payable by a sublessee or assignee (or a combination of the rental payable under such sublease or assignment plus any bonus or other
consideration therefor or incident thereto in any form) exceeds the sum of the rental payable under this Lease (excluding however, any Rent payable under this Section) and actual and reasonable brokerage fees, legal costs and any design or
construction fees directly related to and required pursuant to the terms of any such sublease (such excess, the Excess Rent), then Tenant shall be bound and obligated to pay Landlord as Additional Rent hereunder 50% of such Excess
Rent within 10 days following receipt thereof by Tenant. If Tenant shall sublet the Premises or any part thereof, Tenant hereby immediately and irrevocably assigns to Landlord, as security for Tenants obligations under this Lease, all rent
from any such subletting, and Landlord as assignee and as attorney-in-fact for Tenant, or a receiver for Tenant appointed on Landlords application, may collect
such rent and apply it toward Tenants obligations under this Lease; except that, until the occurrence of a Default, Tenant shall have the right to collect such rent. (e) No Waiver.The consent by Landlord to an assignment or subletting shall not relieve Tenant or any assignees of this Lease or
any sublessees of the Premises from obtaining the consent of Landlord to any further assignment or subletting nor shall it release Tenant or any assignee or sublessee of Tenant from full and primary liability under the Lease. The acceptance of Rent
hereunder, or the acceptance of performance of any other term, covenant, or condition thereof, from any other person or entity shall not be deemed to be a waiver of any of the provisions of this Lease or a consent to any subletting, assignment or
other transfer of the Premises. (f) Prior Conduct of Proposed Transferee.Notwithstanding any other provision of this
Section22, if (i) the proposed assignee or sublessee of Tenant has been required by any prior landlord, lender or Governmental Authority to take remedial action in connection with Hazardous Materials contaminating a
property, where the contamination resulted from such partys action or use of the property in question, (ii) the proposed assignee or sublessee is subject to an enforcement order issued by any Governmental Authority in connection with the
use, storage, handling, treatment, generation, release or disposal of Hazardous Materials (including, without limitation, any order related to the failure to make a required reporting to any Governmental Authority), or (iii) because of the
existence of a pre-existing environmental condition in the vicinity of or underlying the Project, the risk that Landlord would be targeted as a responsible party in connection with the remediation of such pre-existing environmental condition would be materially increased or exacerbated by the proposed use of Hazardous Materials by such proposed assignee or sublessee, Landlord shall have the absolute right to refuse
to consent to any assignment or subletting to any such party.  LOGO

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1400 One Kendall Square/Solid Biosciences  Page
 25  23. Estoppel Certificate. Tenant shall, within 10 business days of written notice from
Landlord, execute, acknowledge and deliver a statement in writing in any form reasonably requested by a proposed lender or purchaser, (i) certifying that this Lease is unmodified and in full force and effect (or, if modified, stating the nature
of such modification and certifying that this Lease as so modified is in full force and effect) and the dates to which the rental and other charges are paid in advance, if any, (ii) acknowledging that there are not any uncured defaults on the
part of Landlord hereunder, or specifying such defaults if any are claimed, and (iii) setting forth such further information with respect to the status of this Lease or the Premises as may be reasonably requested thereon. Any such statement may
be relied upon by any prospective purchaser or encumbrancer of all or any portion of the real property of which the Premises are a part. Tenants failure to deliver such statement within such time shall, at the option of Landlord, be conclusive
upon Tenant that the Lease is in full force and effect and without modification except as may be represented by Landlord in any certificate prepared by Landlord and delivered to Tenant for execution. 24. Quiet Enjoyment. So long as Tenant shall perform all of the covenants and agreements herein required to be performed by Tenant,
Tenant shall, subject to the terms of this Lease, at all times during the Term, have peaceful and quiet enjoyment of the Premises against any person claiming by, through or under Landlord. 25. Prorations. All prorations required or permitted to be made hereunder shall be made on the basis of a 360 day year and 30 day
months. 26. Rules and Regulations. Tenant shall, at all times during the Term and any extension thereof, comply with all
reasonable rules and regulations at any time or from time to time established by Landlord and delivered to Tenant in writing covering use of the Premises and the Project or portion thereof of which the Premises are a part. The current rules and
regulations are attached hereto as Exhibit E. If there is any conflict between said rules and regulations and other provisions of this Lease, the terms and provisions of this Lease shall control. Landlord shall not have any liability or
obligation for the breach of any rules or regulations by other tenants in the Project and shall not enforce such rules and regulations in a discriminatory manner. 27. Subordination. This Lease and Tenants interest and rights hereunder are hereby made and shall be subject and subordinate at
all times to the lien of any Mortgage now existing or hereafter created on or against the Project, Property, Building or Premises, and all amendments, restatements, renewals, modifications, consolidations, refinancing, assignments and extensions
thereof, without the necessity of any further instrument or act on the part of Tenant; provided, however that so long as there is no Default hereunder, Tenants right to possession of the Premises shall not be disturbed by the
Holder of any such Mortgage. Tenant agrees, at the election of the Holder of any such Mortgage, to attorn to any such Holder. Tenant agrees upon demand to execute, acknowledge and deliver such instruments, confirming such subordination, and such
instruments of attornment as shall be requested by any such Holder, provided any such instruments contain appropriate non-disturbance provisions assuring Tenants quiet enjoyment of the Premises as set
forth in Section24 hereof. Notwithstanding the foregoing, any such Holder may at any time subordinate its Mortgage to this Lease, without Tenants consent, by notice in writing to Tenant, and thereupon this Lease
shall be deemed prior to such Mortgage without regard to their respective dates of execution, delivery or recording and in that event such Holder shall have the same rights with respect to this Lease as though this Lease had been executed prior to
the execution, delivery and recording of such Mortgage and had been assigned to such Holder. The term Mortgage whenever used in this Lease shall be deemed to include deeds of trust, security assignments, ground leases or other
superior leases and any other encumbrances, and any reference to the Holder of a Mortgage shall be deemed to include the beneficiary under a deed of trust.  LOGO

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1400 One Kendall Square/Solid Biosciences  Page
 26  28. Surrender. Upon the expiration of the Term or earlier termination of Tenants
right of possession, Tenant shall surrender the Premises to Landlord in the same condition as received, subject to any Alterations or Installations permitted by Landlord to remain in the Premises, free of Hazardous Materials brought upon, kept,
used, stored, handled, treated, generated in, or released or disposed of from, the Premises by any person other than a Landlord Party (collectively, Tenant HazMat Operations) and released of all Hazardous Materials Clearances,
broom clean, ordinary wear and tear and casualty loss and condemnation covered by Sections 18 and 19 excepted. At least 3 months prior to the surrender of the Premises, Tenant shall deliver to Landlord a narrative description of the
actions proposed (or required by any Governmental Authority) to be taken by Tenant in order to surrender the Premises (including any Installations permitted by Landlord to remain in the Premises) at the expiration or earlier termination of the Term,
free from any residual impact from the Tenant HazMat Operations and otherwise released for unrestricted use and occupancy (the Surrender Plan). Such Surrender Plan shall be accompanied by a current listing of (i) all
Hazardous Materials licenses and permits held by or on behalf of any Tenant Party with respect to the Premises, and (ii) all Hazardous Materials used, stored, handled, treated, generated, released or disposed of from the Premises, and shall be
subject to the review and approval of Landlords environmental consultant. In connection with the review and approval of the Surrender Plan, upon the request of Landlord, Tenant shall deliver to Landlord or its consultant such additional non-proprietary information concerning Tenant HazMat Operations as Landlord shall request. On or before such surrender, Tenant shall deliver to Landlord evidence that the approved Surrender Plan shall have been
satisfactorily completed and Landlord shall have the right, subject to reimbursement at Tenants expense as set forth below, to cause Landlords environmental consultant to inspect the Premises and perform such additional procedures as may
be deemed reasonably necessary to confirm that the Premises are, as of the effective date of such surrender or early termination of the Lease, free from any residual impact from Tenant HazMat Operations. Tenant shall reimburse Landlord, as
Additional Rent, for the actual out-of-pocket expense incurred by Landlord for Landlords environmental consultant to review and approve the Surrender Plan and to
visit the Premises and verify satisfactory completion of the same, which cost shall not exceed $5, 000. Landlord shall have the unrestricted right to deliver such Surrender Plan and any report by Landlords environmental consultant with respect
to the surrender of the Premises to third parties. If Tenant shall fail to prepare or submit a Surrender Plan approved by Landlord, or if
Tenant shall fail to complete the approved Surrender Plan, or if such Surrender Plan, whether or not approved by Landlord, shall fail to adequately address any residual effect of Tenant HazMat Operations in, on or about the Premises, Landlord shall
have the right to take such actions as Landlord may deem reasonable or appropriate to assure that the Premises and the Project are surrendered free from any residual impact from Tenant HazMat Operations, the cost of which actions shall be reimbursed
by Tenant as Additional Rent, without regard to the limitation set forth in the first paragraph of this Section28. Tenant shall immediately return to Landlord all keys and/or access cards to parking, the Building, restrooms or all or any portion of the
Premises, Building or Project furnished to or otherwise procured by Tenant. If any such access card or key is lost, Tenant shall pay to Landlord, at Landlords election, either the cost of replacing such lost access card or key or the cost of
reprogramming the access security system in which such access card was used or changing the lock or locks opened by such lost key. Any Tenants Property, Alterations and property not so removed by Tenant as permitted or required herein shall be
deemed abandoned and may be stored, removed, and disposed of by Landlord at Tenants expense, and Tenant waives all claims against Landlord for any damages resulting from Landlords retention and/or disposition of such property. All
obligations of Tenant hereunder not fully performed as of the termination of the Term, including the obligations of Tenant under Section30 hereof, shall survive the expiration or earlier termination of the Term, including,
without limitation, indemnity obligations, payment obligations with respect to Rent and obligations concerning the condition and repair of the Premises. 29. Waiver of Jury Trial. TENANT AND LANDLORD WAIVE ANY RIGHT TO TRIAL BY JURY OR TO HAVE A JURY PARTICIPATE IN RESOLVING ANY DISPUTE,
WHETHER SOUNDING IN CONTRACT, TORT, OR OTHERWISE, BETWEEN LANDLORD AND TENANT ARISING OUT OF THIS LEASE OR ANY OTHER INSTRUMENT, DOCUMENT, OR AGREEMENT EXECUTED OR DELIVERED IN CONNECTION HEREWITH OR THE TRANSACTIONS RELATED HERETO.  LOGO

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Multi-Tenant Laboratory

1400 One Kendall Square/Solid Biosciences  Page
 27  30. Environmental Requirements. (a) Prohibition/Compliance/Indemnity. Tenant shall not cause or permit any Hazardous Materials (as hereinafter defined) to be brought
upon, kept, used, stored, handled, treated, generated in or about, or released or disposed of from, the Premises, Building, Property or Project in violation of applicable Environmental Requirements (as hereinafter defined) by Tenant or any Tenant
Party. If Tenant breaches the obligation stated in the preceding sentence, or if the presence of Hazardous Materials in the Premises during the Term or any holding over results in contamination of the Premises, Building, Property or Project or any
adjacent property or if contamination of the Premises, Building, Property or Project or any adjacent property by Hazardous Materials brought into, kept, used, stored, handled, treated, generated in or about, or released or disposed of from, the
Premises by anyone other than Landlord and Landlords employees, agents and contractors otherwise occurs during the Term or any holding over, Tenant hereby indemnifies and shall defend and hold Landlord, its officers, directors, employees,
agents and contractors harmless from any and all actions (including, without limitation, remedial or enforcement actions of any kind, administrative or judicial proceedings, and orders or judgments arising out of or resulting therefrom), costs,
claims, damages (including, without limitation, punitive damages and damages based upon diminution in value of the Premises or the Project, or the loss of, or restriction on, use of the Premises or any portion of the Project), expenses (including,
without limitation, attorneys, consultants and experts fees, court costs and amounts paid in settlement of any claims or actions), fines, forfeitures or other civil, administrative or criminal penalties, injunctive or other relief
(whether or not based upon personal injury, property damage, or contamination of, or adverse effects upon, the environment, water tables or natural resources), liabilities or losses (collectively, Environmental Claims) which arise
during or after the Term as a result of such contamination or breach by Tenant of its obligations under this Section30. This indemnification of Landlord by Tenant includes, without limitation, costs incurred in connection
with any investigation of site conditions or any cleanup, treatment, remedial, removal, or restoration work required by any federal, state or local Governmental Authority because of Hazardous Materials present in the air, soil or ground water above,
on, or under the Premises. Without limiting the foregoing, if the presence of any Hazardous Materials on the Premises, Building, Property, Project or any adjacent property caused or permitted by Tenant or any Tenant Party results in any
contamination of the Premises, Building, Property, Project or any adjacent property, Tenant shall promptly take all actions at its sole expense and in accordance with applicable Environmental Requirements as are necessary to return the Premises,
Building, Property, Project or any adjacent property to the condition existing prior to the time of such contamination, provided that Landlords approval of such action shall first be obtained, which approval shall not unreasonably be withheld
so long as such actions would not potentially have any material adverse long-term or short-term effect on the Premises, Building, Property or the Project. Notwithstanding anything to the contrary contained in Section28 or
this Section30, Tenant shall not be responsible for, and the indemnification and hold harmless obligation set forth in this paragraph shall not apply to (i) contamination in the Premises which Tenant can prove to
Landlords reasonable satisfaction existed in the Premises immediately prior to the Commencement Date, or (ii) the presence of any Hazardous Materials in the Premises which Tenant can prove to Landlords reasonable satisfaction
migrated from outside of the Premises into the Premises, unless in either case, the presence of such Hazardous Materials (x) is the result of a breach by Tenant of any of its obligations under this Lease, or (y) was caused, contributed to
or exacerbated by Tenant or any Tenant Party. (b) Business. Landlord acknowledges that it is not the intent of this
Section30 to prohibit Tenant from using the Premises for the Permitted Use. Tenant may operate its business according to prudent industry practices so long as the use or presence of Hazardous Materials is strictly and
properly monitored according to all then applicable Environmental Requirements. As a material inducement to Landlord to allow Tenant to use Hazardous Materials in connection with its business, Tenant agrees to deliver to Landlord prior to the
Commencement Date a list identifying each type of Hazardous Materials (other than Hazardous Material contained in products customarily used by tenants in de minimis quantities for ordinary cleaning and office purposes) to be brought upon, kept,
used, stored, handled, treated, generated on, or released or disposed of from, the Premises and setting forth any and all governmental approvals or permits required in connection with the presence, use, storage, handling, treatment, generation,
release or disposal of such Hazardous Materials on or from the Premises (Hazardous Materials List).  LOGO

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 28  Upon Landlords request, or any time that Tenant is required to deliver a Hazardous Materials List to any Governmental Authority (e.g., the fire department) in connection with Tenants
use or occupancy of the Premises, Tenant shall deliver to Landlord a copy of such Hazardous Materials List. Tenant shall deliver to Landlord true and correct copies of the following documents (the Haz Mat Documents) relating to
the use, storage, handling, treatment, generation, release or disposal of Hazardous Materials prior to the Commencement Date, or if unavailable at that time, concurrent with the receipt from or submission to a Governmental Authority: permits;
approvals; reports and correspondence; storage and management plans, notice of violations of any Legal Requirements; plans relating to the installation of any storage tanks to be installed in or under the Building or Property (provided, said
installation of tanks shall only be permitted after Landlord has given Tenant its written consent to do so, which consent may be withheld in Landlords sole and absolute discretion); all closure plans or any other documents required by any and
all federal, state and local Governmental Authorities for any storage tanks installed in, on or under the Building or Property for the closure of any such tanks; and a Surrender Plan (to the extent surrender in accordance with
Section28 cannot be accomplished in 3 months). Tenant is not required, however, to provide Landlord with any portion(s) of the Haz Mat Documents containing information of a proprietary nature which, in and of themselves,
do not contain a reference to any Hazardous Materials or hazardous activities. It is not the intent of this Section to provide Landlord with information which could be detrimental to Tenants business should such information become possessed by
Tenants competitors. (c) Tenant Representation and Warranty. Tenant hereby represents and warrants to Landlord that
(i) neither Tenant nor any of its legal predecessors has been required by any prior landlord, lender or Governmental Authority at any time to take remedial action in connection with Hazardous Materials contaminating a property which
contamination was permitted by Tenant of such predecessor or resulted from Tenants or such predecessors action or use of the property in question, and (ii) Tenant is not subject to any enforcement order issued by any Governmental
Authority in connection with the use, storage, handling, treatment, generation, release or disposal of Hazardous Materials (including, without limitation, any order related to the failure to make a required reporting to any Governmental Authority).
If Landlord determines that this representation and warranty was not true as of the date of this lease, Landlord shall have the right to terminate this Lease in Landlords sole and absolute discretion. (d) Testing. Landlord shall have the right to conduct annual tests of the Premises to determine whether any contamination of the
Premises, Building, Property or Project has occurred as a result of Tenants use. Tenant shall be required to pay the cost of such annual test of the Premises if there is violation of this Section30 or if
contamination for which Tenant is responsible under this Section30 is identified; provided, however, that if Tenant conducts its own tests of the Premises using third party contractors and test procedures acceptable to
Landlord which tests are certified to Landlord, Landlord shall accept such tests in lieu of the annual tests to be paid for by Tenant. In addition, at any time, and from time to time, prior to the expiration or earlier termination of the Term,
Landlord shall have the right to conduct appropriate tests of the Premises, Building, Property and Project to determine if contamination has occurred as a result of Tenants use of the Premises. In connection with such testing, upon the request
of Landlord, Tenant shall deliver to Landlord or its consultant such non-proprietary information concerning the use of Hazardous Materials in or about the Premises by Tenant or any Tenant Party. If
contamination has occurred for which Tenant is liable under this Section30, Tenant shall pay all costs to conduct such tests. If no such contamination is found, Landlord shall pay the costs of such tests (which shall not
constitute an Operating Expense). Landlord shall provide Tenant with a copy of all third party, non-confidential reports and tests of the Premises made by or on behalf of Landlord during the Term without
representation or warranty and subject to a confidentiality agreement. Tenant shall, at its sole cost and expense, promptly and satisfactorily remediate any environmental conditions identified by such testing for which Tenant is responsible under
this Lease in accordance with all Environmental Requirements. Landlords receipt of or satisfaction with any environmental assessment in no way waives any rights which Landlord may have against Tenant. (e) Underground Tanks. Tenant shall have no right to use or install any underground storage tanks at the Project.  LOGO

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1400 One Kendall Square/Solid Biosciences  Page
 29  (f) Tenants Obligations. Tenants obligations under this
Section30 shall survive the expiration or earlier termination of the Lease. During any period of time after the expiration or earlier termination of this Lease required by Tenant or Landlord to complete the removal from
the Premises of any Hazardous Materials (including, without limitation, the release and termination of any licenses or permits restricting the use of the Premises and the completion of the approved Surrender Plan), Tenant shall continue to pay the
full Rent in accordance with this Lease for any portion of the Premises not relet by Landlord in Landlords sole discretion, which Rent shall be prorated daily. (g) Definitions. As used herein, the term Environmental Requirements means all applicable present and future
statutes, regulations, ordinances, rules, codes, judgments, orders or other similar enactments of any Governmental Authority regulating or relating to health, safety, or environmental conditions on, under, or about the Premises, Building, Property
or Project, or the environment, including without limitation, the following: the Comprehensive Environmental Response, Compensation and Liability Act; the Resource Conservation and Recovery Act; and all state and local counterparts thereto, and any
regulations or policies promulgated or issued thereunder. As used herein, the term Hazardous Materials means and includes any substance, material, waste, pollutant, or contaminant listed or defined as hazardous or toxic, or
regulated by reason of its impact or potential impact on humans, animals and/or the environment under any Environmental Requirements, asbestos and petroleum, including crude oil or any fraction thereof, natural gas liquids, liquefied natural gas, or
synthetic gas usable for fuel (or mixtures of natural gas and such synthetic gas). As defined in Environmental Requirements, Tenant is and shall be deemed to be the operator of Tenants facility and the
owner of all Hazardous Materials brought on the Premises by Tenant or any Tenant Party, and the wastes, by-products, or residues generated, resulting, or produced therefrom. (h) Asbestos. (i) Notification of Asbestos. Landlord hereby notifies Tenant of the presence of asbestos-containing materials
(ACMs) and/or presumed asbestos-containing materials (PACMs) within or about the Premises in the locations identified in Exhibit G. (ii) Tenant Acknowledgement. Tenant hereby acknowledges receipt of the notification in paragraph (i) of this
Section30(h) and understand that the purpose of such notification is to make Tenant, and any agents, employees, and contractors of Tenant, aware of the presence of ACMs and/or PACMs within or about the Building in order to
avoid or minimize any damage to or disturbance of such ACMs and/or PACMs. /s/
IG Tenants Initials (iii) Acknowledgement from Contractors/Employees. Tenant
shall give Landlord at least 14 days prior written notice before conducting, authorizing or permitting any of the activities listed below within or about the Premises, and before soliciting bids from any person to perform such services. Such
notice shall identify or describe the proposed scope, location, date and time of such activities and the name, address and telephone number of each person who may be conducting such activities. Thereafter, Tenant shall grant Landlord reasonable
access to the Premises to determine whether any ACMs or PACMs will be disturbed in connection with such activities. Tenant shall not solicit bids from any person for the performance of such activities without Landlords prior written approval.
Upon Landlords request, Tenant shall deliver to Landlord a copy of a signed acknowledgement from any contractor, agent, or employee of Tenant acknowledging receipt of information describing the presence of ACMs and/or PACMs within or about the
Premises in the locations identified in Exhibit G prior to the commencement of such activities. Nothing in this Section30(h) shall be deemed to expand Tenants rights under the Lease or otherwise to conduct,
authorize or permit any such activities.  LOGO

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1400 One Kendall Square/Solid Biosciences - Page
 30  (A) Removal of thermal system insulation (TSI) and
surfacing ACMs and PACMs (i.e., sprayed-on or troweled-on material, e.g., textured ceiling paint or fireproofing material); (B) Removal of ACMs or PACMs that are not TSI or surfacing ACMs or PACMs; or (C) Repair and maintenance of operations that are likely to disturb ACMs or PACMs. 31. Tenants Remedies/Limitation of Liability. Landlord shall not be in default hereunder unless Landlord fails to perform any of
its obligations hereunder within 30 days after written notice from Tenant specifying such failure (unless such performance will, due to the nature of the obligation, require a period of time in excess of 30 days, then after such period of time as is
reasonably necessary). Upon any default by Landlord, Tenant shall give notice by registered or certified mail to any Holder of a Mortgage covering the Premises and to any landlord of any lease of property in or on which the Premises are located and
Tenant shall offer such Holder and/or landlord a reasonable opportunity to cure the default, including time to obtain possession of the Project, or portion thereof of which the Premises are a part, by power of sale or a judicial action if such
should prove necessary to effect a cure; provided Landlord shall have furnished to Tenant in writing the names and addresses of all such persons who are to receive such notices. All obligations of Landlord hereunder shall be construed as
covenants, not conditions; and, except as may be otherwise expressly provided in this Lease, Tenant may not terminate this Lease for breach of Landlords obligations hereunder. All obligations of Landlord under this Lease will be binding upon Landlord only during the period of its ownership of the Premises and not
thereafter. The term Landlord in this Lease shall mean only the owner for the time being of the Premises. Upon the transfer by such owner of its interest in the Premises and the assumption of its interests by the transferee, such
owner shall thereupon be released and discharged from all obligations of Landlord thereafter accruing, but such obligations shall be binding during the Term upon each new owner for the duration of such owners ownership. 32. Inspection and Access. Landlord and its agents, representatives, and contractors may enter the Premises at any reasonable time to
inspect the Premises and to make such repairs as may be required or permitted pursuant to this Lease and for any other business purpose. Landlord and Landlords representatives may enter the Premises during business hours on not less than 48
hours advance written notice (except in the case of emergencies in which case no such notice shall be required and such entry may be at any time) for the purpose of effecting any such repairs, inspecting the Premises, showing the Premises to
prospective purchasers and, during the last year of the Term, to prospective tenants or for any other business purpose. Landlord may erect a suitable sign on the Premises, Building or Property stating the Premises or Building are available to let or
that the Building, Property or Project is available for sale. Landlord shall use reasonable efforts to minimize interference with Tenants business operations at the Premises in connection with its entry into the Premises under this
Section32. Landlord may grant easements, make public dedications, designate Common Areas and create restrictions on or about the Premises, Building and Property, provided that no such easement, dedication,
designation or restriction materially, adversely affects Tenants use or occupancy of the Premises for the Permitted Use. At Landlords request, Tenant shall execute such instruments as may be necessary for such easements, dedications or
restrictions. Tenant shall at all times, except in the case of emergencies, have the right to escort Landlord or its agents, representatives, contractors or guests while the same are in the Premises, provided such escort does not materially and
adversely affect Landlords access rights hereunder. 33. Security. Tenant acknowledges and agrees that security devices and
services, if any, while intended to deter crime may not in given instances prevent theft or other criminal acts and that Landlord is not providing any security services with respect to the Premises. Tenant agrees that Landlord shall not be liable to
Tenant for, and Tenant waives any claim against Landlord with respect to, any loss by theft or any other damage suffered or incurred by Tenant in connection with any unauthorized entry into the  LOGO

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1400 One Kendall Square/Solid Biosciences  Page
 31  Premises or any other breach of security with respect to the Premises. Tenant shall be solely responsible for the personal safety of Tenants officers, employees, agents, contractors, guests
and invitees while any such person is in, on or about the Premises, Building, Property and/or Project. Tenant shall at Tenants cost obtain insurance coverage to the extent Tenant desires protection against such criminal acts. 34. Force Majeure. Except for the payment of Rent, neither Landlord nor Tenant shall be held responsible or liable for delays in the
performance of its obligations hereunder when caused by, related to, or arising out of acts of God, strikes, lockouts, or other labor disputes, embargoes, quarantines, weather, national, regional, or local disasters, calamities, or catastrophes,
inability to obtain labor or materials (or reasonable substitutes therefor) at reasonable costs or failure of, or inability to obtain, utilities necessary for performance, governmental restrictions, orders, limitations, regulations, or controls,
national emergencies, delay in issuance or revocation of permits, enemy or hostile governmental action, terrorism, insurrection, riots, civil disturbance or commotion, fire or other casualty, and other causes or events beyond their reasonable
control (Force Majeure). 35. Brokers. Landlord and Tenant each represents and warrants that it has not dealt
with any broker, agent or other person (collectively, Broker) in connection with this transaction and that no Broker brought about this transaction, other than Newmark Knight Frank. Landlord and Tenant each hereby agree to indemnify and
hold the other harmless from and against any claims by any Broker, other than the broker, if any named in this Section35, claiming a commission or other form of compensation by virtue of having dealt with Tenant or
Landlord, as applicable, with regard to this leasing transaction. Landlord shall be responsible for all commissions due to Newmark Knight Frank arising out of the execution of this Lease in accordance with the terms of a separate written agreement
between Newmark Knight Frank and Landlord. 36. Limitation on Landlords Liability. NOTWITHSTANDING ANYTHING SET FORTH
HEREIN OR IN ANY OTHER AGREEMENT BETWEEN LANDLORD AND TENANT TO THE CONTRARY: (A) LANDLORD SHALL NOT BE LIABLE TO TENANT OR ANY OTHER PERSON FOR (AND TENANT AND EACH SUCH OTHER PERSON ASSUME ALL RISK OF) LOSS, DAMAGE OR INJURY, WHETHER ACTUAL
OR CONSEQUENTIAL TO: TENANTS PERSONAL PROPERTY OF EVERY KIND AND DESCRIPTION, INCLUDING, WITHOUT LIMITATION TRADE FIXTURES, EQUIPMENT, INVENTORY, SCIENTIFIC RESEARCH, SCIENTIFIC EXPERIMENTS, LABORATORY ANIMALS, PRODUCT, SPECIMENS, SAMPLES,
AND/OR SCIENTIFIC, BUSINESS, ACCOUNTING AND OTHER RECORDS OF EVERY KIND AND DESCRIPTION KEPT AT THE PREMISES AND ANY AND ALL INCOME DERIVED OR DERIVABLE THEREFROM; (B) THERE SHALL BE NO PERSONAL RECOURSE TO LANDLORD FOR ANY ACT OR OCCURRENCE
IN, ON OR ABOUT THE PREMISES OR ARISING IN ANY WAY UNDER THIS LEASE OR ANY OTHER AGREEMENT BETWEEN LANDLORD AND TENANT WITH RESPECT TO THE SUBJECT MATTER HEREOF AND ANY LIABILITY OF LANDLORD HEREUNDER SHALL BE STRICTLY LIMITED SOLELY TO
LANDLORDS INTEREST IN THE PROPERTY OR ANY PROCEEDS FROM SALE OR CONDEMNATION THEREOF AND ANY INSURANCE PROCEEDS PAYABLE IN RESPECT OF LANDLORDS INTEREST IN THE PROPERTY OR IN CONNECTION WITH ANY SUCH LOSS; AND (C) IN NO EVENT SHALL
ANY PERSONAL LIABILITY BE ASSERTED AGAINST ANY OF LANDLORDS OFFICERS, DIRECTORS, EMPLOYEES, AGENTS OR CONTRACTORS. UNDER NO CIRCUMSTANCES SHALL LANDLORD OR ANY OF LANDLORDS OFFICERS, DIRECTORS, EMPLOYEES, AGENTS OR CONTRACTORS BE LIABLE
FOR INJURY TO TENANTS BUSINESS OR FOR ANY LOSS OF INCOME OR PROFIT THEREFROM. NOTWITHSTANDING ANYTHING TO THE CONTRARY CONTAINED IN
THIS LEASE, IN NO EVENT SHALL PERSONAL LIABILITY FOR TENANTS OBLIGATIONS UNDER THIS LEASE BE ASSERTED AGAINST ANY OF TENANTS OFFICERS, DIRECTORS, EMPLOYEES OR AGENTS. 37. Severability. If any clause or provision of this Lease is illegal, invalid or unenforceable under present or future laws, then and
in that event, it is the intention of the parties hereto that the remainder of this Lease shall not be affected thereby. It is also the intention of the parties to this Lease that in lieu of each clause or provision of this Lease that is illegal,
invalid or unenforceable, there be added, as a part of this Lease, a clause or provision as similar in effect to such illegal, invalid or unenforceable clause or provision as shall be legal, valid and enforceable.  LOGO

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1400 One Kendall Square/Solid Biosciences  Page
 32  38. Signs; Exterior Appearance. Tenant shall not, without the prior written consent of
Landlord, which may be granted or withheld in Landlords sole discretion: (i) attach any awnings, exterior lights, decorations, balloons, flags, pennants, banners, painting or other projection to any outside wall of the Building,
(ii) use any curtains, blinds, shades or screens other than Landlords standard window coverings, (iii) coat or otherwise sunscreen the interior or exterior of any windows, (iv) place any bottles, parcels, or other articles on
the window sills, (v) place any equipment, furniture or other items of personal property on any exterior balcony, or (vi) paint, affix or exhibit on any part of the Premises, Building, Property or Project any signs, notices, window or door
lettering, placards, decorations, or advertising media of any type which can be viewed from the exterior of the Premises. Standard signage on the floor on which the Premises is located and the directory tablet shall be inscribed, painted or affixed
for Tenant by Landlord at Landlords cost, and shall be of a size, color and type acceptable to Landlord. Nothing may be placed on the exterior of corridor walls or corridor doors other than Landlords standard lettering. The directory
tablet shall be provided exclusively for the display of the name and location of tenants. 39. Right to Extend Term. Tenant shall
have the right to extend the Term of the Lease upon the following terms and conditions: (a) Extension Rights.Tenant shall
have the right (the Extension Right) to extend the term of this Lease for one additional 2 year term (the Extension Term) on the same terms and conditions as this Lease (other than Base Rent and the Work Letter)
by giving Landlord written notice of its election to exercise the Extension Right at least 12 months prior to the expiration of the Base Term of the Lease. Upon the commencement of the Extension Term, Base Rent shall be payable at the Market Rate (as defined below). Base Rent shall thereafter be
adjusted on each annual anniversary of the commencement of the Extension Term by a percentage as determined by Landlord and agreed to by Tenant at the time the Market Rate is determined. As used herein, Market Rateshall mean the
then market rental rate for comparably improved laboratory space in the East Cambridge submarket of Boston as determined by Landlord and agreed to by Tenant, or determined by arbitration as provided below. In addition, Landlord may impose a market
rent for the parking rights provided hereunder. If, on or before the date which is 210 days prior to the expiration of the Base Term of
this Lease, Tenant has not agreed with Landlords determination of the Market Rate and the rent escalations during the Extension Term after negotiating in good faith, Tenant shall be deemed to have elected arbitration as described in
Section39(b). Tenant acknowledges and agrees that, if Tenant has elected to exercise the Extension Right by delivering notice to Landlord as required in this Section39(a), Tenant shall have no
right thereafter to rescind or elect not to extend the term of the Lease for the Extension Term. (b) Arbitration. (i) Within 10 days of Tenants notice to Landlord of its election (or deemed election) to arbitrate Market Rate and
escalations, each party shall deliver to the other a proposal containing the Market Rate and escalations that the submitting party believes to be correct (Extension Proposal). If either party fails to timely submit an Extension
Proposal, the other partys submitted proposal shall determine the Base Rent and escalations for the Extension Term. If both parties submit Extension Proposals, then Landlord and Tenant shall meet within 7 days after delivery of the last
Extension Proposal and make a good faith attempt to mutually appoint a single Arbitrator (and defined below) to determine the Market Rate and escalations. If Landlord and Tenant are unable to agree upon a single Arbitrator, then each shall, by
written notice delivered to the other within 10 days after the meeting, select an Arbitrator. If either party fails to timely give notice of its selection for an Arbitrator, the other partys submitted proposal shall determine the Base  LOGO

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1400 One Kendall Square/Solid Biosciences  Page
 33  Rent for the Extension Term. The 2 Arbitrators so appointed shall, within 5 business days after their appointment, appoint a third Arbitrator. If the 2 Arbitrators so selected cannot agree on the
selection of the third Arbitrator within the time above specified, then either party, on behalf of both parties, may request such appointment of such third Arbitrator by application to any state court of general jurisdiction in the jurisdiction in
which the Premises are located, upon 10 days prior written notice to the other party of such intent. (ii) The decision of
the Arbitrator(s) shall be made within 30 days after the appointment of a single Arbitrator or the third Arbitrator, as applicable. The decision of the single Arbitrator shall be final and binding upon the parties. The average of the two closest
Arbitrators in a three Arbitrator panel shall be final and binding upon the parties. Each party shall pay the fees and expenses of the Arbitrator appointed by or on behalf of such party and the fees and expenses of the third Arbitrator shall be
borne equally by both parties. If the Market Rate and escalations are not determined by the first day of the Extension Term, then Tenant shall pay Landlord Base Rent in an amount equal to the Base Rent in effect immediately prior to the Extension
Term and increased by the Rent Adjustment Percentage until such determination is made. After the determination of the Market Rate and escalations, the parties shall make any necessary adjustments to such payments made by Tenant. Landlord and Tenant
shall then execute an amendment recognizing the Market Rate and escalations for the Extension Term. (iii) An
Arbitrator shall be any person appointed by or on behalf of either party or appointed pursuant to the provisions hereof and: (i) shall be (A) a member of the American Institute of Real Estate Appraisers with not less
than 10 years of experience in the appraisal of improved office and life sciences space in the greater Cambridge, Massachusetts metropolitan area, or (B) a licensed commercial real estate broker with not less than 15 years experience
representing landlords and/or tenants in the leasing of office and life sciences space in the greater Cambridge, Massachusetts metropolitan area; (ii) devoting substantially all of their time to professional appraisal or brokerage work, as
applicable, at the time of appointment; and (iii) shall be in all respects impartial and disinterested. (c) Rights Personal.
The Extension Right is personal to Tenant and is not assignable without Landlords consent, which may be granted or withheld in Landlords sole discretion separate and apart from any consent by Landlord to an assignment of Tenants
interest in the Lease, except that they may be assigned in connection with any Permitted Assignment of this Lease. (d) Exceptions.
Notwithstanding anything set forth above to the contrary, the Extension Right shall, at Landlords option, not be in effect and Tenant may not exercise the Extension Right: (i) during any period of time that Tenant is in default (beyond any applicable notice and cure periods) under any provision of
this Lease; or (ii) if Tenant has been in Default under any provision of this Lease 3 or more times, whether or not the
Defaults are cured, during the 12 month period immediately prior to the date that Tenant intends to exercise the Extension Right, whether or not the Defaults are cured. (iii) except for a Permitted Assignment, if Tenant is not in occupancy of at least 75% of the entire Premises demised hereunder
both at the time of the exercise of the Extension Right and at the time of the commencement date of the Extension Term. (e) No
Extensions. The period of time within which the Extension Right may be exercised shall not be extended or enlarged by reason of Tenants inability to exercise the Extension Right.  LOGO

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1400 One Kendall Square/Solid Biosciences  Page
 34  (f) Termination. The Extension Right shall, at Landlords option, terminate and
be of no further force or effect even after Tenants due and timely exercise of the Extension Right, if, after such exercise, but prior to the commencement date of the Extension Term, (i) Tenant fails to timely cure any default by Tenant
under this Lease; or (ii) Tenant has Defaulted 3 or more times during the period from the date of the exercise of the Extension Right to the date of the commencement of the Extension Term, whether or not such Defaults are cured. 40. Miscellaneous. (a)
Notices. All notices or other communications between the parties shall be in writing and shall be deemed duly given upon delivery or refusal to accept delivery by the addressee thereof if delivered in person, or upon actual receipt if
delivered by reputable overnight guaranty courier, addressed and sent to the parties at their addresses set forth above. Landlord and Tenant may from time to time by written notice to the other designate another address for receipt of future
notices. (b) Joint and Several Liability. If and when included within the term Tenant, as used in this
instrument, there is more than one person or entity, each shall be jointly and severally liable for the obligations of Tenant. (c)
Financial Information. Upon written request from Landlord, Tenant shall furnish Landlord with true and complete copies of (i) Tenants most recent audited annual financial statements within 120 days of the end of each of
Tenants fiscal years during the Term, and (ii) Tenants most recent unaudited quarterly financial statements within 75 days of the end of each of Tenants first three fiscal quarters of each of Tenants fiscal years during
the Term. If the stock of Tenant is publicly traded on a recognized national exchange, then Tenants filing of quarterly and annual financial statements with the Securities and Exchange Commission shall be deemed to satisfy Tenants
obligations to deliver financial statements under this Section. (d) Recordation. Neither this Lease nor a memorandum of lease
shall be filed by or on behalf of Tenant in any public record. Landlord may prepare and file, and upon request by Landlord Tenant will execute, a memorandum of lease. (e) Interpretation. The normal rule of construction to the effect that any ambiguities are to be resolved against the drafting party
shall not be employed in the interpretation of this Lease or any exhibits or amendments hereto. Words of any gender used in this Lease shall be held and construed to include any other gender, and words in the singular number shall be held to include
the plural, unless the context otherwise requires. The captions inserted in this Lease are for convenience only and in no way define, limit or otherwise describe the scope or intent of this Lease, or any provision hereof, or in any way affect the
interpretation of this Lease. (f) Not Binding Until Executed. The submission by Landlord to Tenant of this Lease shall have no
binding force or effect, shall not constitute an option for the leasing of the Premises, nor confer any right or impose any obligations upon either party until execution of this Lease by both parties. (g) Entire Agreement;Amendment. This Lease constitutes the entire agreement between Landlord and Tenant pertaining to the lease
of the Premises and supersedes all other agreements, whether oral or written, pertaining to the lease of the Premises, and no other agreements with respect thereto shall be effective. Any amendments or modifications of this Lease shall be in writing
and signed by both Landlord and Tenant, and any other attempted amendment or modification of this Lease shall be void. (h) Limitations
on Interest. It is expressly the intent of Landlord and Tenant at all times to comply with applicable law governing the maximum rate or amount of any interest payable on or in connection with this Lease. If applicable law is ever judicially
interpreted so as to render usurious any interest called for under this Lease, or contracted for, charged, taken, reserved, or received with respect to this Lease, then it is Landlords and Tenants express intent that all excess amounts
theretofore collected  LOGO

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 35  by Landlord be credited on the applicable obligation (or, if the obligation has been or would thereby be paid
in full, refunded to Tenant), and the provisions of this Lease immediately shall be deemed reformed and the amounts thereafter collectible hereunder reduced, without the necessity of the execution of any new document, so as to comply with the
applicable law, but so as to permit the recovery of the fullest amount otherwise called for hereunder. (i) Choice of Law.
Construction and interpretation of this Lease shall be governed by the internal laws of the Commonwealth of Massachusetts, excluding any principles of conflicts of laws. (j) Time. Time is of the essence as to the performance of Tenants obligations under this Lease. (k) OFAC. Tenant, and all beneficial owners of Tenant, are currently (a) in compliance with, and shall at all times during the
Term of this Lease remain in compliance with, the regulations of the Office of Foreign Assets Control (OFAC) of the U.S. Department of Treasury and any statute, executive order, or regulation relating thereto (collectively, the
OFAC Rules), (b) not listed on, and shall not during the Term of this Lease be listed on, the Specially Designated Nationals and Blocked Persons List maintained by OFAC and/or on any other similar list maintained by OFAC or other
governmental authority pursuant to any authorizing statute, executive order, or regulation, and (c) not a person or entity with whom a U.S. person is prohibited from conducting business under the OFAC Rules. (l) Incorporation by Reference. All exhibits and addenda attached hereto are hereby incorporated into this Lease and made a part
hereof. If there is any conflict between such exhibits or addenda and the terms of this Lease, such exhibits or addenda shall control. (m) No Accord and Satisfaction. No payment by Tenant or receipt by Landlord of a lesser amount than the monthly installment of Base
Rent or any Additional Rent will be other than on account of the earliest stipulated Base Rent and Additional Rent, nor will any endorsement or statement on any check or letter accompanying a check for payment of any Base Rent or Additional Rent be
an accord and satisfaction. Landlord may accept such check or payment without prejudice to Landlords right to recover the balance of such Rent or to pursue any other remedy provided in this Lease. (n) Hazardous Activities. Notwithstanding any other provision of this Lease, Landlord, for itself and its employees, agents and
contractors, reserves the right to refuse to perform any repairs or services in any portion of the Premises which, pursuant to Tenants routine safety guidelines, practices or custom or prudent industry practices, require any form of protective
clothing or equipment other than safety glasses. In any such case, Tenant shall contract with parties who are acceptable to Landlord, in Landlords reasonable discretion, for all such repairs and services, and Landlord shall, to the extent
required, equitably adjust Tenants Share of Operating Expenses in respect of such repairs or services to reflect that Landlord is not providing such repairs or services to Tenant. [Signatures on next page]  LOGO

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1400 One Kendall Square/Solid Biosciences  Page
 36  IN WITNESS WHEREOF, Landlord and Tenant have executed this Lease as of the day and year first
above written.  TENANT:SOLID BIOSCIENCES, LLC, a
Delaware limited liability companyBy:

/s/ Ilan GanotPrint Name:

Ilan GanotTitle:

CEO
  LANDLORD:ARE-MA REGION NO. 59, LLC,
a Delaware limited liability companyBy:

ALEXANDRIA REAL ESTATE EQUITIES, L.P.,
a Delaware limited partnership, managing
member
 By:

ARE-QRS CORP.,
a Maryland corporation, general
partner
 By:

/s/ Jackie ClemPrint Name:

Jackie ClemTitle:

Senior Vice President RE Legal
Affairs
  LOGO

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1400 One Kendall Square/Solid Biosciences  Page 1  EXHIBIT A TO LEASE DESCRIPTION OF PREMISES  LOGO  LOGO

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Work Letter - Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 1  EXHIBIT B TO LEASE DESCRIPTION OF PROPERTY Real
property in the County of Middlesex, Commonwealth of Massachusetts, described as follows: Buildings 100, 200, 300, 400 and 500: Four registered parcels of land located in the City of Cambridge, Middlesex County, Massachusetts, bounded and described as follows: Lot 35 - L.C. Plan 10378G Commencing at the intersection
of the northeasterly line of Hampshire Street with the southeasterly line of Cardinal Medeiros Avenue; Thence running N 36°0635 E along
said southeasterly line of Cardinal Medeiros Avenue, a distance of 262.69 feet, to a point; Thence running S 53°4658 E, by land now or
formerly of Trustees of Old Kendall Realty Trust, a distance of 322.66 feet, to a point; Thence running S 36°1640 W, by Lot 42 shown on
Land Court Plan 10378J, a distance of 48.01 feet, to a point; Thence running by Lot 36, shown on Land Court Plan 10378G, on the following four
(4) courses: N 53°4039 W, a distance of 65.11 feet, to a point; S 36°0450 W, a distance of 126.58 feet, to a point; S 53°3232 E, a distance of 42.30 feet, to a point; and S 28°3458 E, a distance of 12.62 feet, to a point at land now or formerly of Trustees of Kendall Three Realty Trust; Thence running S 60°2150 W, in part by land of said Trustees and in part by land now or formerly of Charles Stark Draper Laboratory, Inc. a
distance of 205.87 feet, to a point on the aforesaid northeasterly line of Hampshire Street; Thence running N 28°5410 W, along said
northeasterly line of Hampshire Street, a distance of 250.01 feet, to the Point of Beginning. Together with the benefit of easement rights set forth in
an Easement from The Charles Stark Draper Laboratory, Inc. to Cambridge Athenaeum LLC, dated April 16, 2000 and filed as Document No. 1137082. Lot 36-L.C. Plan 10378G Commencing at a point on the easterly line of the above described parcel, said point being S 36°1640 W and a distance of 48.01 feet from the
northeast corner of the above described parcel; Thence running S 36°1640 W, by land of the Trustees of Kendall Three Realty Trust, a
distance of 107.52 feet; to a point;  LOGO

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Work Letter - Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 2  Thence running S 60°2150 W, by land of said Trustees, a distance of 26.84 feet, to a point; Thence running by Lot 35, shown on Land Court Plan 10378G, on the following four (4) courses: N 28°3458 W, a distance of 12.62 feet, to a point; N 53°3232 W, a distance of 42.30 feet, to a point; N 36°0450 E, a distance 126.58 feet, to a point; and S 53°4039 E, a distance of 65.11 feet, to the Point of Beginning. Lot 42 - Land Court Plan 10378J Commencing at the
northeast corner of Lot 35, hereinbefore described; Thence running by land, now or formerly of Trustees of Kendall Three Realty Trust, on the following
three (3) courses: S 53°4658 E, a distance of 1.97 feet, to a point; S 36°2525 W, a distance of 48.02 feet, to a point; and N 53°4039 W, a distance of 1.85 feet, to a point; Thence running N 36°1640 E, by Lot 35, a distance of 48.01 feet, to the Point of Beginning. Lot 43 - Land Court Plan 10378J A certain parcel of land
situate in Cambridge in the County of Middlesex, Commonwealth of Massachusetts: Northeasterly by lot 39 as shown on plan hereinafter mentioned, thirteen
and 05/100 feet; Southeasterly forty-eight and 04/100 feet; and Southwesterly thirteen and 28/100 feet by lot 41 on said plan; and Northwesterly by lot 42 on said plan, forty-eight and 02/100 feet. Said parcel is shown as Lot 43 on Land Court Plan 10378J. All
of said boundaries are determined by the Court to be located as shown on a subdivision plan, as approved by the Court, filed in the Land Registration Office, a copy of which is filed in the Registry of Deeds in Registration Book 1050, Page 90, with
Certificate 184040. Together with the rights and easements set forth in that certain Grant of Easement from Charles Stark Draper Laboratory, Inc. dated
August 31, 1983, filed with the Middlesex County Registry District of the Land Court (the District) as Document No. 657256. Together with the rights and easements set forth in that certain Easements Agreement dated December 17, 1984 and filed as Document No. 673502, as
affected by Amendment to Easements Agreement, dated April 7, 2006 and filed as Document No. 1416496.  LOGO

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Work Letter - Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 3  Together with the rights and easements set forth in a Grant of Easement dated August 30,1983 and filed
as Document No. 654750. Together with the rights and easements set forth in a Grant of Easement from the City of Cambridge, dated January 29,
2009 and recorded in Book 52168, Page 362. The foregoing parcels collectively are also described as follows: Those certain parcels of registered land located in Cambridge, Middlesex County, Massachusetts, shown as Lots 35 and 36 on Land Court Plan 10378G and Lots 42
and 43 shown on Land Court Plan 10378J, bounded and described as follows: Beginning at the point on the northeasterly sideline of Hampshire Street 250.01
feet distance southeasterly from intersection of easterly sideline of Cardinal Medeiros Avenue and northeasterly side line of Hampshire Street thence bounded: Southwesterly by the northeasterly line of Hampshire Street, two hundred fifty and 01/100 (250.01) feet; Northwesterly by the southeasterly line of Cardinal Medeiros Avenue, two hundred sixty two and 69/100 (262.69) feet; Northeasterly by land now or formerly of Cambridge Athenaeum LLC, three hundred thirty seven and 68/100 (337.68) feet; Southeasterly by land now or formerly of Amgen Cambridge Real Estate Holdings Inc., forty-eight and 04/100 (48.04) feet; Southwesterly by land of said Amgen Cambridge Real Estate Holdings Inc., fifteen and 13/100 (15.13) feet; Southeasterly by said land now or formerly of Amgen Cambridge Real Estate Holdings Inc., one hundred seven and 52/100 (107.52) feet; and Southeasterly by land now or formerly of Amgen Cambridge Real Estate Holdings Inc. and Charles Stark Draper Laboratory, Inc., two hundred thirty two and
71/100 (232.71) feet. Buildings 600, 650 and 700: Lot 39 - Land Court Plan 10378H That certain parcel of
land situated in the City of Cambridge, Middlesex County, Massachusetts, bounded and described as follows: Commencing at a point on the Easterly side of
Cardinal Medeiros Avenue, said point being sixty feet from the intersection of said Easterly side of Cardinal Medeiros Avenue and the Southerly line of Binney Street; Northerly, by Lot 40 shown in Land Court Plan 103781, two hundred thirty-eight and sixty-three hundredths (238.63) feet,
eighty-two and forty-one hundredths (82.41) feet and seventeen and four hundredths (17.04) feet; Easterly, by Lots 40 and 41 shown on Land Court Plan 10378l, one hundred ninety-six and eighty-four hundredths
(196.84) feet,  LOGO

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Work Letter - Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 4  Southerly by Lots 43 and 42 shown on Land Court Plan 10378J and Lot 35 shown on Land Court Plan 10378G three
hundred thirty-seven and sixty-eight hundredths (337.68) feet; Westerly, on aforesaid Cardinal Medeiros Avenue, one hundred ninety-nine and seventy-one hundredths (199.71) feet. The parcel of land described above is shown as Lot 39 on Land Court Plan 10378H. Lot 40 (Building 1400) The land with the
buildings and improvements thereon, shown as Lot 40 on Land Court Plan 10378l, situated on Binney Street in the City of Cambridge, County of Middlesex, Massachusetts, also shown on a plan entitled Topographic Plan for Old Binney Realty Trust,
Cardinal Medeiros Avenue, Binney Street; Cambridge, Massachusetts, dated June 29, 1987, as revised July 10, 1987, April 13, 1988, August 12, 1988, September 6, 1988, and September 26, 1988, prepared by cullinan
Engineering Co., Inc., being bounded and described as follows; NORTHEASTERLY by the southwesterly line of Binney Street, two hundred sixty-six and 80/100 (266.80) feet and two hundred twenty and 44/100 (220.44) feet; EASTERLY by land now or formerly of
Consolidated Rail Corporation, eighty-nine and 24/100 (89.24) feet; SOUTHWESTERLY by Lot 41 on Land Court Plan 103781, twenty seven and 16/100 (27.16)
feet; SOUTHWESTERLY by said Lot 41, thirty-five and 12/100 (35.12) feet and one hundred two and 73/100 (102.73) feet; NORTHWESTERLY by Lot 39 on Land Court Plan 10378H, sixty-six and 15/100 (66.15) feet; SOUTHWESTERLY by said Lot 39, seventeen and 04/100 (17.04) feet; SOUTHWESTERLY by said Lot 39, eighty-two and 41/100 (82.41) feet; SOUTHWESTERLY by said Lot 39, two hundred thirty-eight and 63/100 (238.63) feet; NORTHWESTERLY by Cardinal Medeiros Avenue (formerly known as Portland Street), sixty and 00/100 (60) feet. Together with the rights set forth in Easements Agreement dated December 17, 1984, between Old Cambridge Realty Trust and the Old Kendall Trustees, filed
as Document No. 673502, as affected by Amendment to Easements Agreement, dated April 7, 2006 and filed as Document No. 1416496. Together
with the rights set forth in Parking Access Easement Agreement filed as Document No. 771896, as affected by Release of Parking Rights by Robert A. Jones and George Najarian, Trustees of Old Binney Realty Trust, dated January 11, 1995,
recorded in Book 25122, Page 94 and filed as Document No. 966485, Release of Parking Rights by Robert A. Jones, Managing Trustee of Old Cambridge Realty Trust dated January 11, 1995, recorded in Book 25122, Page 98 and filed as Document
No. 966486; Release of Parking Rights by Robert A. Jones, Managing Trustee of Old Kendall Realty Trust, dated January 11, 1995, recorded in Book 25122, Page 102 and filed as Document No.966487; Release of Parking Rights by State Street
Bank and Trust Company, Trustees of Kendall One Realty Trust dated January 5, 1995, recorded in Book 25122, Page 106 and filed as Document No. 966488, and Release of Parking Rights dated January 10, 1995, recorded in Book 25153, Page
386 and as filed as Document No. 967459.  LOGO

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Work Letter - Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 5  Together with the rights set forth in that certain Parking and Access Easement Agreement, by and between DWF
IV One Kendall, LLC and DWF IV One Kendall Garage, LLC, dated as of January 16, 2014 and recorded in Book 63188, Page 559, and filed as Document No. 1663415.  LOGO

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Work Letter  Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 1  EXHIBIT C TO LEASE WORK LETTER THIS
WORK LETTER (this Work Letter) is attached to and incorporated into that certain Lease dated December 22, 2017 (the Lease) by and between ARE-MA REGION NO.
59, LLC, a Delaware limited liability company (Landlord), and SOLID BIOSCIENCES, LLC, a Delaware limited liability company (Tenant). Any initially capitalized terms used but not defined herein shall
have the meanings given them in the Lease.  1.
General Requirements. (a) Tenants Authorized
Representative. Tenant designates Alvaro Amorrortu and Patrick Guinee (either such individual acting alone, Tenants Representative) as the only persons authorized to act for Tenant pursuant to this Work Letter.
Landlord shall not be obligated to respond to or act upon any request, approval, inquiry or other communication (Communication) from or on behalf of Tenant in connection with this Work Letter unless such Communication is in
writing from Tenants Representative. Tenant may change either Tenants Representative at any time upon not less than 5 business days advance written notice to Landlord. (b) Landlords Authorized Representative. Landlord designates Tim White and Mike Carli (either such individual acting
alone, Landlords Representative) as the only persons authorized to act for Landlord pursuant to this Work Letter. Tenant shall not be obligated to respond to or act upon any request, approval, inquiry or other Communication
from or on behalf of Landlord in connection with this Work Letter unless such Communication is in writing from Landlords Representative. Landlord may change either Landlords Representative at any time upon not less than 5 business days
advance written notice to Tenant. (c) Architects, Consultants and Contractors. Landlord and Tenant hereby acknowledge and agree
that the architect (the TI Architect) for the Tenant Improvements (as defined in Section2(a) below), the general contractor and any subcontractors for the Tenant Improvements shall be selected by Tenant,
subject to Landlords approval, which approval shall not be unreasonably withheld, conditioned or delayed. Landlord shall be named a third party beneficiary of any contract entered into by Tenant with the TI Architect, any consultant, any
contractor or any subcontractor, and of any warranty made by any contractor or any subcontractor.  2.
Tenant Improvements. (a) Tenant Improvements Defined. As used
herein, Tenant Improvements shall mean all improvements to the Premises desired by Tenant of a fixed and permanent nature. Other than funding the TI Allowance (as defined below) as provided herein, Landlord shall not have any
obligation whatsoever with respect to the finishing of the Premises for Tenants use and occupancy. (b) Tenants Space
Plans. Tenant shall deliver to Landlord schematic drawings and outline specifications (the TI Design Drawings) detailing Tenants requirements for the Tenant Improvements within 10 days of the date hereof. Not more
than 10 days thereafter, Landlord shall deliver to Tenant the written objections, questions or comments of Landlord and the TI Architect with regard to the TI Design Drawings. Tenant shall cause the TI Design Drawings to be revised to address such
written comments and shall resubmit said drawings to Landlord for approval within 10 days thereafter. Such process shall continue until Landlord has approved the TI Design Drawings. (c) Working Drawings. Not later than 15 business days following the approval of the TI Design Drawings by Landlord, Tenant shall cause
the TI Architect to prepare and deliver to Landlord for review and comment construction plans, specifications and drawings for the Tenant Improvements (TI Construction Drawings),  LOGO

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Work Letter  Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 2  which TI Construction Drawings shall be prepared substantially in accordance with the TI Design Drawings. Tenant shall be solely responsible for ensuring that the TI Construction Drawings
reflect Tenants requirements for the Tenant Improvements. Landlord shall deliver its written comments on the TI Construction Drawings to Tenant not later than 10 business days after Landlords receipt of the same; provided, however, that
Landlord may not disapprove any matter that is consistent with the TI Design Drawings. Tenant and the TI Architect shall consider all such comments in good faith and shall, within 10 business days after receipt, notify Landlord how Tenant proposes
to respond to such comments. Any disputes in connection with such comments shall be resolved in accordance with Section2(d) hereof. Provided that the design reflected in the TI Construction Drawings is consistent with the TI
Design Drawings, Landlord shall approve the TI Construction Drawings submitted by Tenant. Once approved by Landlord, subject to the provisions of Section4 below, Tenant shall not materially modify the TI Construction
Drawings except as may be reasonably required in connection with the issuance of the TI Permit (as defined in Section3(a) below). (d) Approval and Completion.If any dispute regarding the design of the Tenant Improvements is not settled within 10 business
days after notice of such dispute is delivered by one party to the other, Tenant may make the final decision regarding the design of the Tenant Improvements, provided (i) Tenant acts reasonably and such final decision is either consistent with
or a compromise between Landlords and Tenants positions with respect to such dispute, (ii) that all costs and expenses resulting from any such decision by Tenant shall be payable out of the TI Fund (as defined in
Section5(d) below), and (iii) Tenants decision will not affect the base Building, structural components of the Building or any Building systems (in which case Landlord shall make the final decision). Any changes
to the TI Construction Drawings following Landlords and Tenants approval of same requested by Tenant shall be processed as provided in Section4 hereof.  3.
Performance of the Tenant Improvements. (a) Commencement and Permitting of
the Tenant Improvements.Tenant shall not commence construction of the Tenant Improvements prior to obtaining and delivering to Landlord a building permit (the TI Permit) authorizing the construction of the Tenant
Improvements consistent with the TI Construction Drawings approved by Landlord. The cost of obtaining the TI Permit shall be payable from the TI Fund. Landlord shall assist Tenant in obtaining the TI Permit. Prior to the commencement of the Tenant
Improvements, Tenant shall deliver to Landlord a copy of any contract with Tenants contractors (including the TI Architect), and certificates of insurance from any contractor performing any part of the Tenant Improvement evidencing industry
standard commercial general liability, automotive liability, builders risk, and workers compensation insurance. Tenant shall cause the general contractor to provide a certificate of insurance naming Landlord, Alexandria Real
Estate Equities, Inc., and Landlords lender (if any) as additional insureds for the general contractors liability coverages required above. (b) Selection of Materials, Etc.Where more than one type of material or structure is indicated on the TI Construction Drawings
approved by Tenant and Landlord, the option will be within Tenants reasonable discretion if the matter concerns the Tenant Improvements, and within Landlords sole and absolute subjective discretion if the matter concerns the structural
components of the Building or any Building system. (c) Tenant Liability.Tenant shall be responsible for correcting any
deficiencies or defects in the Tenant Improvements. (d) Substantial Completion.Tenant shall substantially complete or
cause to be substantially completed the Tenant Improvements in a good and workmanlike manner, in accordance with the TI Permit subject, in each case, to Minor Variations and normal punch list items of a
non-material nature which do not interfere with the use of the Premises (Substantial Completion or Substantially Complete). Upon Substantial Completion of the Tenant
Improvements, Tenant shall require the TI Architect and the general contractor to execute and deliver, for the benefit of Tenant and Landlord, a Certificate of Substantial Completion in the form of the American Institute of Architects
(AIA) document  LOGO

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Work Letter  Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 3  G704. For purposes of this Work Letter, Minor Variations shall mean any modifications reasonably required: (i) to comply with all applicable Legal Requirements and/or to
obtain or to comply with any required permit (including the TI Permit); (ii) to comport with good design, engineering, and construction practices which are not material; or (iii) to make reasonable adjustments for field deviations or conditions
encountered during the construction of the Tenant Improvements. 4. Changes. Any changes requested by Tenant to the Tenant
Improvements after the delivery and approval by Landlord of the TI Design Drawings, shall be requested and instituted in accordance with the provisions of this Section4 and shall be subject to the written approval of
Landlord, which approval shall not be unreasonably withheld, conditioned or delayed. (a) Tenants Right to Request Changes.
If Tenant shall request changes (Changes), Tenant shall request such Changes by notifying Landlord in writing in substantially the same form as the AIA standard change order form (a Change Request), which Change
Request shall detail the nature and extent of any such Change. Such Change Request must be signed by Tenants Representative. Landlord shall review and approve or disapprove such Change Request within 10 business days thereafter, provided that
Landlords approval shall not be unreasonably withheld, conditioned or delayed. (b) Implementation of Changes. If Landlord
approves such Change and Tenant deposits with Landlord any Excess TI Costs (as defined in Section5(d) below) required in connection with such Change, Tenant may cause the approved Change to be instituted. If any TI Permit
modification or change is required as a result of such Change, Tenant shall promptly provide Landlord with a copy of such TI Permit modification or change. 5. Costs. (a) Budget
For Tenant Improvements. Before the commencement of construction of the Tenant Improvements, Tenant shall obtain a detailed breakdown, by trade, of the costs incurred or that will be incurred, in connection with the design and construction of
the Tenant Improvements (the Budget), and deliver a copy of the Budget to Landlord for Landlords approval, which shall not be unreasonably withheld or delayed. The Budget shall be based upon the TI Construction Drawings
approved by Landlord. If the Budget is greater than the TI Allowance, Tenant shall deposit with Landlord the difference, in cash, prior to the commencement of construction of the Tenant Improvements, for disbursement by Landlord as described in
Section5(d). (b) TI Allowance. Landlord shall provide to Tenant a tenant improvement allowance
(TI Allowance) of $60.00 per rentable square foot of the Premises, or $569,340.00 in the aggregate. Notwithstanding anything to the contrary contained herein, if Tenant surrenders its existing premises at 161 First Street,
Cambridge, Massachusetts, in accordance with the surrender requirements of that certain Lease Agreement dated as of February 29, 2016, between Tenant, as tenant, and ARE-MA Region No. 21, LLC, a
Delaware limited liability company, as landlord (the 161 Lease), on or before February 15, 2018, and Tenant is not otherwise in Default (as defined in the 161 Lease) under the 161 Lease, then the TI Allowance shall be
increased by $15.00 per rentable square foot of the Premises. The TI Allowance shall be disbursed in accordance with this Work Letter.
Tenant shall have no right to the use or benefit (including any reduction to Base Rent) of any portion of the TI Allowance not required for the construction of (i) the Tenant Improvements described in the TI Construction Drawings approved
pursuant to Section2(d) or (ii) any Changes pursuant to Section4. Tenant shall have no right to any portion of the TI Allowance that is not disbursed before the last day of the month that is
18 months after the Commencement Date. (c) Costs Includable in TI Fund. The TI Fund shall be used solely for the payment of design,
permits and construction costs in connection with the construction of the Tenant Improvements, including, without limitation, the cost of electrical power and other utilities used in connection with the  LOGO

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Work Letter  Tenant Build

1400 One Kendall Square/Solid Biosciences  Page 4  construction of the Tenant Improvements, the cost of preparing the TI Design Drawings and the TI Construction Drawings, all costs set forth in the Budget and the cost of Changes (collectively,
TI Costs). Notwithstanding anything to the contrary contained herein, the TI Fund shall not be used to purchase any furniture, personal property or other non-Building system materials or
equipment, including, but not be limited to, Tenants voice or data cabling, non-ducted biological safety cabinets and other scientific equipment not incorporated into the Tenant Improvements. (d) Excess TI Costs.Landlord shall have no obligation to bear any portion of the cost of any of the Tenant Improvements except
to the extent of the TI Allowance. If at any time and from time-to-time, the remaining TI Costs under the Budget exceed the remaining unexpended TI Allowance
(Excess TI Costs), monthly disbursements of the TI Allowance shall be made in the proportion that the remaining TI Allowance bears to the outstanding TI Costs under the Budget, and Tenant shall fund the balance of each monthly
draw. For purposes of any litigation instituted with regard to such amounts, those amounts will be deemed Rent under the Lease. The TI Allowance and Excess TI Costs is herein referred to as the TI Fund. Notwithstanding anything to
the contrary set forth in this Section5(d), Tenant shall be fully and solely liable for TI Costs and the cost of Minor Variations in excess of the TI Allowance. (e) Payment for TI Costs.During the course of design and construction of the Tenant Improvements, subject to the terms of
Section5(d) above, Landlord shall reimburse Tenant for TI Costs once a month against a draw request in Landlords standard form, containing evidence of payment of such Tl Costs by Tenant and such certifications, lien
waivers (including a conditional lien release for each progress payment and unconditional lien releases for the prior months progress payments), inspection reports and other matters as Landlord customarily obtains, to the extent of
Landlords approval thereof for payment, no later than 30 days following receipt of such draw request. Upon completion of the Tenant Improvements (and prior to any final disbursement of the TI Fund), Tenant shall deliver to Landlord:
(i) sworn statements setting forth the names of all contractors and first tier subcontractors who did the work and final, unconditional lien waivers from all such contractors and first tier subcontractors;
(ii) as-built plans (one copy in print format and two copies in electronic CAD format) for such Tenant Improvements; (iii) a certification of substantial completion in Form AIA G704, (iv) a
certificate of occupancy for the Premises; and (v) copies of all operation and maintenance manuals and warranties affecting the Premises.  6.
Miscellaneous. (a) Consents.Whenever consent or approval of either
party is required under this Work Letter, that party shall not unreasonably withhold, condition or delay such consent or approval, except as may be expressly set forth herein to the contrary. (b) Modification.No modification, waiver or amendment of this Work Letter or of any of its conditions or provisions shall be binding
upon Landlord or Tenant unless in writing signed by Landlord and Tenant. (c) Default.Notwithstanding anything set forth herein or
in the Lease to the contrary, Landlord shall not have any obligation to perform any work hereunder or to fund any portion of the TI Fund during any period Tenant is in Default under the Lease.  LOGO

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Acknowledgment of Commencement Date

1400 One Kendall Square/Solid Biosciences  Page 1  EXHIBIT D TO LEASE ACKNOWLEDGMENT OF COMMENCEMENT DATE This ACKNOWLEDGMENT OF COMMENCEMENT DATEis made as of this
 day of ,
 between ARE-MA REGION NO. 59, LLC,a Delaware limited liability company (Landlord),and
SOLID BIOSCIENCES, LLC,a Delaware limited liability company (Tenant),and is attached to and made a part of the Lease dated as of
November, 2017 (the Lease),by and between Landlord and Tenant. Any initially capitalized terms used but not defined herein shall have
the meanings given them in the Lease. Landlord and Tenant hereby acknowledge and agree, for all purposes of the Lease, that the
Commencement Date of the Base Term of the Lease is ,
, the Rent Commencement Date is ,
, and the termination date of the Base Term of the Lease shall be midnight on
, ,. In case of a conflict between this
Acknowledgment of Commencement Date and the Lease, this Acknowledgment of Commencement Date shall control for all purposes. IN WITNESS
WHEREOF, Landlord and Tenant have executed this ACKNOWLEDGMENT OF COMMENCEMENT DATE to be effective on the date first above written.  TENANT:SOLID BIOSCIENCES, LLC,a Delaware limited liability company
 By:
 Print Name:
 Title:
  LANDLORD:ARE-MA REGION NO. 59, LLC,a Delaware limited liability company
 By:

ALEXANDRIA REAL ESTATE EQUITIES, L.P.,a Delaware limited partnership, managing member
 By:

ARE-QRS CORP.,a Maryland corporation, general partner
 By:
 Print Name:
 Title:
  LOGO

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Rules and Regulations

1400 One Kendall Square/Solid Biosciences  Page 1  EXHIBIT E TO LEASE RULES AND REGULATIONS 1. The sidewalk, entries, and driveways of the Building, Property or Project shall not be obstructed by Tenant, or any Tenant Party, or used
by them for any purpose other than ingress and egress to and from the Premises. 2. Tenant shall not place any objects, including
antennas, outdoor furniture, etc., in the parking areas, landscaped areas or other areas outside of its Premises, or on the roof of the Building. 3. Except for animals assisting the disabled, no animals shall be allowed in the offices, halls, or corridors in the Building, Property or
Project. 4. Tenant shall not disturb the occupants of the Building, Property or Project or adjoining buildings by the use of any radio or
musical instrument or by the making of loud or improper noises. 5. If Tenant desires telegraphic, telephonic or other electric
connections in the Premises, Landlord or its agent will direct the electrician as to where and how the wires may be introduced; and, without such direction, no boring or cutting of wires will be permitted. Any such installation or connection shall
be made at Tenants expense. 6. Tenant shall not install or operate any steam or gas engine or boiler, or other mechanical apparatus
in the Premises, except as specifically approved in the Lease. The use of oil, gas or inflammable liquids for heating, lighting or any other purpose is expressly prohibited. Explosives or other articles deemed extra hazardous shall not be brought
into the Building, Property or Project. 7. Parking any type of recreational vehicles is specifically prohibited on or about the Building,
Property or Project. Except for the overnight parking of operative vehicles, no vehicle of any type shall be stored in the parking areas at any time. In the event that a vehicle is disabled, it shall be removed within 48 hours. There shall be no
For Sale or other advertising signs on or about any parked vehicle. All vehicles shall be parked in the designated parking areas in conformity with all signs and other markings. All parking will be open parking, and no reserved parking,
numbering or lettering of individual spaces will be permitted except as specified by Landlord. 8. Tenant shall maintain the Premises free
from rodents, insects and other pests. 9. Landlord reserves the right to exclude or expel from the Building, Property or Project any
person who, in the judgment of Landlord, is intoxicated or under the influence of liquor or drugs or who shall in any manner do any act in violation of the Rules and Regulations of the Building, Property or Project. 10. Tenant shall not cause any unnecessary labor by reason of Tenants carelessness or indifference in the preservation of good order and
cleanliness. Landlord shall not be responsible to Tenant for any loss of property on the Premises, however occurring, or for any damage done to the effects of Tenant by the janitors or any other employee or person. 11. Tenant shall give Landlord prompt notice of any defects in the water, lawn sprinkler, sewage, gas pipes, electrical lights and fixtures,
heating apparatus, or any other service equipment affecting the Premises. 12. Tenant shall not permit storage outside the Premises,
including without limitation, outside storage of trucks and other vehicles, or dumping of waste or refuse or permit any harmful materials to be placed in any drainage system or sanitary system in or about the Premises.  LOGO

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Rules and Regulations

1400 One Kendall Square/Solid Biosciences  Page 2  13. All moveable trash receptacles provided by the trash disposal firm for the Premises must
be kept in the trash enclosure areas, if any, provided for that purpose. 14. No auction, public or private, will be permitted on the
Premises, Building, Property or Project. 15. No awnings shall be placed over the windows in the Premises except with the prior written
consent of Landlord. 16. The Premises shall not be used for lodging, sleeping or cooking or for any immoral or illegal purposes or for
any purpose other than that specified in the Lease. No gaming devices shall be operated in the Premises. 17. Tenant shall ascertain from
Landlord the maximum amount of electrical current which can safely be used in the Premises, taking into account the capacity of the electrical wiring in the Building, Property and Premises and the needs of other tenants, and shall not use more than
such safe capacity. Landlords consent to the installation of electric equipment shall not relieve Tenant from the obligation not to use more electricity than such safe capacity. 18. Tenant assumes full responsibility for protecting the Premises from theft, robbery and pilferage. 19. Tenant shall not install or operate on the Premises any machinery or mechanical devices of a nature not directly related to Tenants
ordinary use of the Premises and shall keep all such machinery free of vibration, noise and air waves which may be transmitted beyond the Premises.  LOGO

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Tenants Personal Property

1400 One Kendall Square/Solid Biosciences  Page 1  EXHIBIT F TO LEASE TENANTS PERSONAL PROPERTY None.  LOGO

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1400 One Kendall Square/Solid Biosciences  Page 1  EXHIBIT G TO LEASE NOTIFICATION OF THE PRESENCE OF ASBESTOS CONTAINING MATERIALS This notification provides certain information about asbestos within or about the Premises at Building 1400, One Kendall Square, Boston, Massachusetts
(Building). Historically, asbestos was commonly used in building products used in the construction of buildings across the country.
Asbestos-containing building products were used because they are fire-resistant and provide good noise and temperature insulation. Because of their prevalence, asbestos-containing materials, or ACMs, are still sometimes found in buildings today. Building 1400 was constructed in the early 1900s. No specific asbestos sampling/analysis data has been provided. Based on the 2002 visual survey, the
following materials were observed in Building 1400 that might contain asbestos, referred to as presumed asbestos-containing materials or PACMS: Building 1400  Material Description

Material LocationDrywall/joint compound

All Floors: throughout walls; portions of east and center elevator lobby ceilings
 Fourth Floor: locker room ceilings12 gray floor tile and mastic

Basement: west hallway by stairsWhite with gray vinyl sheet flooring

Basement: Microbia glass wash room12 white/blue/pink floor tile and mastic

First Floor: Suntory Pharmaceutical, northwest laboratory, kitchen, and east side rooms
 Second Floor: Microbia, west side laboratory (assumed throughout)White vinyl sheet flooring

First Floor: Suntory Pharmaceutical, south side laboratories12 beige floor tile and mastic

First Floor: loading dock and service elevator hallway12 light gray floor tile and mastic

First Floor: Incert Software, kitchen12 white with gray floor tile and mastic

Second Floor: Microbia, east side hallway by stairs 
Third Floor: Microbia, southwest hallway12 light gray floor tile and mastic

Third Floor: Microbia, center hallway and hallways by center and east stairs12 white with black speck floor tile and mastic

Fourth Floor: Microbia, west end laboratory (assumed throughout)12 gray and white floor tile and mastic

Fourth Floor: Microbia, southwest hallway and east side lunch roomGray rubberized flooring

Fourth and Fifth Floors: Microbia, center stairwell12 dark gray floor tile and mastic

Fifth Floor: Microbia, east side hallway and elevator lobby12 white and gray floor tile and mastic

Fifth Floor: Microbia, east side hallways; west side laboratories (assumed throughout)12 gray floor tile and mastic

Fifth Floor: Microbia, center stairwell landing2 x 4 ceiling tile

First Floor: Suntory Pharmaceutical, laboratory (assumed throughout)2 x 2 ceiling tile (curves pattern)

First Floor: Suntory Pharmaceutical, north offices  LOGO

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1400 One Kendall Square/Solid Biosciences  Page 2  Material Description

Material Location2 x 2 ceiling tile

First Floor: Incert Software, center office areas2 x 2 ceiling tile

First Floor: Genzyme, office areas (assumed throughout) 
Second Floor: Genzyme, east side office areas; Microbia office areas (201) 
Third Floor: Genzyme, southwest hallway, center and east side offices (302-304)
 Fourth Floor: Genzyme, offices and laboratories (assumed throughout)
 Fifth Floor: Genzyme, center and east side offices (assumed throughout)2 x 4 ceiling tile

Second Floor: Microbia, west side laboratory (assumed throughout); Genzyme, center office areas (203)
 Third Floor: Genzyme, west side laboratory (assumed throughout)
 Fifth Floor: Genzyme, west side laboratory (assumed throughout)Fireproofing

All Floors: beams and columns, with some overspray on deckingStucco

Exterior overhang and east side walk area and perimeter of windows Because ACMs and PACMs may be present within or about the Building, we have hired an independent environmental consulting firm
to prepare an operations and maintenance program (O&M Program). The O&M Program is designed to minimize the potential of any harmful asbestos exposure to any person within or about the Building. The O&M Program
includes a description of work methods to be taken in order to maintain any ACMs or PACMs within or about the Building in good condition and to prevent any significant disturbance of such ACMs or PACMs. Appropriate personnel receive regular
periodic training on how to properly administer the O&M Program. The O&M Program describes the risks associated with asbestos exposure and how to
prevent such exposure through appropriate work practices. ACMs and PACMs generally are not thought to be a threat to human health unless asbestos fibers are released into the air and inhaled. This does not typically occur unless (1) the ACMs
are in a deteriorating condition, or (2) the ACMs have been significantly disturbed (such as through abrasive cleaning, or maintenance or renovation activities). If inhaled, asbestos fibers can accumulate in the lungs and, as exposure
increases, the risk of disease (such as asbestosis or cancer) increases. However, measures to minimize exposure, and consequently minimize the accumulation of asbestos fibers, reduce the risks of adverse health effects. The O&M Program describes a number of activities that should be avoided in order to prevent a release of asbestos fibers. In particular, you should be
aware that some of the activities which may present a health risk include moving, drilling, boring, or otherwise disturbing ACMs. Consequently, such activities should not be attempted by any person not qualified to handle ACMs. The O&M Program is available for review during regular business hours at Landlords office located at 400 Technology Square, Suite 101, Cambridge, MA
02139.  LOGO

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RIGHTS RESERVED. Confidential and Proprietary - Do Not Copy or
Distribute. Alexandria and the Alexandria Logo are registered trademarks of Alexandria Real Estate Equities, Inc.