Document:

EX-10.1

 Exhibit 10.1 

UNUM THERAPEUTICS, INC. 
 2015
STOCK INCENTIVE PLAN 
 1. Purpose 

The purpose of this 2015 Stock Incentive Plan (the “Plan”) of Unum Therapeutics, Inc., a Delaware corporation (the
“Company”), is to advance the interests of the Company’s stockholders by enhancing the Company’s ability to attract, retain and motivate persons who are expected to make important contributions to the Company and by providing
such persons with equity ownership opportunities and performance-based incentives that are intended to better align the interests of such persons with those of the Company’s stockholders. Except where the context otherwise requires, the term
“Company” shall include any of the Company’s present or future parent or subsidiary corporations as defined in Sections 424(e) or (f) of the Internal Revenue Code of 1986, as amended, and any regulations promulgated
thereunder (the “Code”) and any other business venture (including, without limitation, joint venture or limited liability company) in which the Company has a controlling interest, as determined by the Board of Directors of the Company (the
“Board”). 
 2. Eligibility 

All of the Company’s employees, officers, directors, consultants and advisors are eligible to be granted options, restricted stock,
restricted stock units (“RSUs”) and other stock-based awards (each, an “Award”) under the Plan. Each person who receives an Award under the Plan is deemed a “Participant”. 

3. Administration and Delegation 
 (a)
Administration by Board of Directors. The Plan will be administered by the Board. The Board shall have authority to grant Awards and to adopt, amend and repeal such administrative rules, guidelines and practices relating to the Plan as it
shall deem advisable. The Board may construe and interpret the terms of the Plan and any Award agreements entered into under the Plan. The Board may correct any defect, supply any omission or reconcile any inconsistency in the Plan or any Award in
the manner and to the extent it shall deem expedient to carry the Plan into effect and it shall be the sole and final judge of such expediency. All decisions by the Board shall be made in the Board’s sole discretion and shall be final and
binding on all persons having or claiming any interest in the Plan or in any Award. No director or person acting pursuant to the authority delegated by the Board shall be liable for any action or determination relating to or under the Plan made in
good faith. 
 (b) Appointment of Committees. To the extent permitted by applicable law, the Board may delegate any or all of its
powers under the Plan to one or more committees or subcommittees of the Board (a “Committee”). All references in the Plan to the “Board” shall mean the Board or a Committee of the Board or the officers referred to in
Section 3(c) to the extent that the Board’s powers or authority under the Plan have been delegated to such Committee or officers. 

 (c) Delegation to Officers. To the extent permitted by applicable law, the Board may
delegate to one or more officers of the Company the power to grant Awards (subject to any limitations under the Plan) to employees or officers of the Company or any of its present or future subsidiary corporations and to exercise such other powers
under the Plan as the Board may determine, provided that the Board shall fix the terms of the Awards to be granted by such officers (including the exercise price of such Awards, which may include a formula by which the exercise price will be
determined) and the maximum number of shares subject to Awards that the officers may grant; provided further, however, that no officer shall be authorized to grant Awards to any “executive officer” of the Company (as defined by Rule 3b-7 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”)) or to any “officer” of the Company (as defined by Rule 16a-1 under the
Exchange Act). 
 4. Stock Available for Awards. 

(a) Number of Shares. Subject to adjustment under Section 8, Awards may be made under the Plan for up to 3,000,000 shares of common
stock, $0.001 par value per share, of the Company (the “Common Stock”). If any Award expires or is terminated, surrendered or canceled without having been fully exercised, is forfeited in whole or in part (including as the result of shares
of Common Stock subject to such Award being repurchased by the Company at the original issuance price pursuant to a contractual repurchase right), or results in any Common Stock not being issued, the unused Common Stock covered by such Award shall
again be available for the grant of Awards under the Plan. Further, shares of Common Stock tendered to the Company by a Participant to exercise an Award shall be added to the number of shares of Common Stock available for the grant of Awards under
the Plan. However, in the case of Incentive Stock Options (as hereinafter defined), the foregoing provisions shall be subject to any limitations under the Code. Shares issued under the Plan may consist in whole or in part of authorized but unissued
shares or treasury shares. At no time while there is any Option (as defined below) outstanding and held by a Participant who was a resident of the State of California on the date of grant of such Option, shall the total number of shares of Common
Stock issuable upon exercise of all outstanding options and the total number of shares provided for under any stock bonus or similar plan or agreement of the Company exceed the applicable percentage as calculated in accordance with the conditions
and exclusions of Section 260.140.45 of the California Code of Regulations (the “California Regulations”), based on the shares of the Company which are outstanding at the time the calculation is made. 

(b) Substitute Awards. In connection with a merger or consolidation of an entity with the Company or the acquisition by the Company of
property or stock of an entity, the Board may grant Awards in substitution for any options or other stock or stock-based awards granted by such entity or an affiliate thereof. Substitute Awards may be granted on such terms as the Board deems
appropriate in the circumstances, notwithstanding any limitations on Awards contained in the Plan. Substitute Awards shall not count against the overall share limit set forth in Section 4(a), except as may be required by reason of
Section 422 and related provisions of the Code. 

  
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 5. Stock Options 

(a) General. The Board may grant options to purchase Common Stock (each, an “Option”) and determine the number of shares of
Common Stock to be covered by each Option, the exercise price of each Option and the conditions and limitations applicable to the exercise of each Option, including conditions relating to applicable federal or state securities laws, as it considers
necessary or advisable. An Option that is not intended to be an Incentive Stock Option (as hereinafter defined) shall be designated a “Nonstatutory Stock Option”.  

(b) Incentive Stock Options. An Option that the Board intends to be an “incentive stock option” as defined in Section 422
of the Code (an “Incentive Stock Option”) shall only be granted to employees of the Company, any of the Company’s present or future parent or subsidiary corporations as defined in Sections 424(e) or (f) of the Code, and any other
entities the employees of which are eligible to receive Incentive Stock Options under the Code. The Option shall be subject to and shall be construed consistently with the requirements of Section 422 of the Code, and without limiting generality
of the foregoing, the Option shall be deemed to include terms that comply with the eligibility standards described section 422(b) of the Code. Subject to the remaining provisions of this Section 5(b), if an Option intended to qualify as an
Incentive Stock Option does not so qualify, the Board may, at its discretion, amend the Plan and Award with respect to such Option so that such Option qualifies as an Incentive Stock Option. To the extent that the aggregate Fair Market Value
(determined at the time of grant) of Common Stock with respect to which Incentive Stock Options are exercisable for the first time by any Participant during any calendar year (under all plans of the Company and any affiliates) exceeds $100,000 (or
such other limit established in the Code) or otherwise does not comply with the rules governing Incentive Stock Options, the Options or portions thereof that exceed such limit (according to the order in which they were granted) or otherwise do not
comply with the rules will be treated as Nonstatutory Stock Options, notwithstanding any contrary provision of the applicable Award. The Company shall have no liability to a Participant, or any other party, if an Option (or any part thereof) that is
intended to be an Incentive Stock Option is not an Incentive Stock Option or for any action taken by the Board, including without limitation the conversion of an Incentive Stock Option to a Nonstatutory Stock Option. 

(c) Exercise Price. The Board shall establish the exercise price of each Option and specify the exercise price in the applicable option
agreement. 
 (d) Duration of Options. Each Option shall be exercisable at such times and subject to such terms and conditions as the
Board may specify in the applicable option agreement. 
 (e) Exercise of Option. Options may be exercised by delivery to the Company
of a written notice of exercise signed by the proper person or by any other form of notice (including electronic notice) approved by the Board together with payment in full as specified in Section 5(f) for the number of shares for which the
Option is exercised. Shares of Common Stock subject to the Option will be delivered by the Company as soon as practicable following exercise. 

(f) Payment Upon Exercise. Common Stock purchased upon the exercise of an Option granted under the Plan shall be paid for as follows:

 (1) in cash or by check, payable to the order of the Company; 

  
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 (2) when the Common Stock is registered under the Exchange Act, except as may otherwise be
provided in the applicable option agreement, by (i) delivery of an irrevocable and unconditional undertaking by a creditworthy broker to deliver promptly to the Company sufficient funds to pay the exercise price and any required tax withholding
or (ii) delivery by the Participant to the Company of a copy of irrevocable and unconditional instructions to a creditworthy broker to deliver promptly to the Company cash or a check sufficient to pay the exercise price and any required tax
withholding; 
 (3) when the Common Stock is registered under the Exchange Act and to the extent provided for in the applicable option
agreement or approved by the Board, in its sole discretion, by delivery (either by actual delivery or attestation) of shares of Common Stock owned by the Participant valued at their fair market value as determined by (or in a manner approved by) the
Board (“Fair Market Value”), provided (i) such method of payment is then permitted under applicable law, (ii) such Common Stock, if acquired directly from the Company, was owned by the Participant for such minimum period of time,
if any, as may be established by the Board in its discretion and (iii) such Common Stock is not subject to any repurchase, forfeiture, unfulfilled vesting or other similar requirements; 

(4) to the extent permitted by applicable law and provided for in the applicable option agreement or approved by the Board, in its sole
discretion, by (i) delivery of a promissory note of the Participant to the Company on terms determined by the Board, or (ii) payment of such other lawful consideration as the Board may determine; or 

(5) by any combination of the above permitted forms of payment. 

6. Restricted Stock; Restricted Stock Units 

(a) General. The Board may grant Awards entitling recipients to acquire shares of Common Stock (“Restricted Stock”), subject
to the right of the Company to repurchase all or part of such shares at their issue price or other stated or formula price (or to require forfeiture of such shares if issued at no cost) from the recipient in the event that conditions specified by
the Board in the applicable Award are not satisfied prior to the end of the applicable restriction period or periods established by the Board for such Award. Instead of granting Awards for Restricted Stock, the Board may grant Awards entitling the
recipient to receive shares of Common Stock or cash to be delivered at the time such Award vests (“Restricted Stock Units”) (Restricted Stock and Restricted Stock Units are each referred to herein as a “Restricted Stock Award”).

 (b) Terms and Conditions for All Restricted Stock Awards. The Board shall determine the terms and conditions of a Restricted Stock
Award, including the conditions for vesting and repurchase (or forfeiture) and the issue price, if any. 
 (c) Additional Provisions
Relating to Restricted Stock. 
 (1) Dividends. Participants holding shares of Restricted Stock will be entitled to all ordinary
cash dividends paid with respect to such shares, unless otherwise provided by the Board. Unless otherwise provided by the Board, if any dividends or distributions are paid in shares, or consist of a dividend or distribution to holders of Common
Stock other than an 

  
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ordinary cash dividend, the shares, cash or other property will be subject to the same restrictions on transferability and forfeitability as the shares of Restricted Stock with respect to which
they were paid. Each dividend payment will be made no later than the end of the calendar year in which the dividends are paid to shareholders of that class of stock or, if later, the 15th day of the third month following the date the dividends are
paid to shareholders of that class of stock. 
 (2) Stock Certificates. The Company may require that any stock certificates issued in
respect of shares of Restricted Stock shall be deposited in escrow by the Participant, together with a stock power endorsed in blank, with the Company (or its designee). At the expiration of the applicable restriction periods, the Company (or such
designee) shall deliver the certificates no longer subject to such restrictions to the Participant or if the Participant has died, to the beneficiary designated, in a manner determined by the Board, by a Participant to receive amounts due or
exercise rights of the Participant in the event of the Participant’s death (the “Designated Beneficiary”). In the absence of an effective designation by a Participant, “Designated Beneficiary” shall mean the
Participant’s estate. 
 7. Other Stock-Based Awards 

Other Awards of shares of Common Stock, and other Awards that are valued in whole or in part by reference to, or are otherwise based on, shares
of Common Stock or other property, may be granted hereunder to Participants (“Other Stock-Based Awards”), including without limitation stock appreciation rights (“SARs”) and Awards entitling recipients to receive shares of Common
Stock to be delivered in the future. Such Other Stock-Based Awards shall also be available as a form of payment in the settlement of other Awards granted under the Plan or as payment in lieu of compensation to which a Participant is otherwise
entitled. Other Stock-Based Awards may be paid in shares of Common Stock or cash, as the Board shall determine. Subject to the provisions of the Plan, the Board shall determine the terms and conditions of each Other Stock-Based Award, including any
purchase price applicable thereto. 
 8. Adjustments for Changes in Common Stock and Certain Other Events 

(a) Changes in Capitalization. In the event of any stock split, reverse stock split, stock dividend, recapitalization, combination of
shares, reclassification of shares, spin-off or other similar change in capitalization or event, or any dividend or distribution to holders of Common Stock other than an ordinary cash dividend, (i) the
number and class of securities available under this Plan, (ii) the number and class of securities and exercise price per share of each outstanding Option, (iii) the number of shares subject to and the repurchase price per share subject to
each outstanding Restricted Stock Award, and (iv) the terms of each other outstanding Award shall be equitably adjusted by the Company (or substituted Awards may be made, if applicable) in the manner determined by the Board; provided that,
unless otherwise determined by the Board, such changes to the Options shall comply with section 1.424-1 of the Treasury Regulations. Without limiting the generality of the foregoing, in the event the Company
effects a split of the Common Stock by means of a stock dividend and the exercise price of and the number of shares subject to an outstanding Option are adjusted as of the date of the distribution of the dividend (rather than as of the record date
for such dividend), then an optionee who exercises an Option between the record date and the distribution date for such stock dividend shall be entitled to receive, on the distribution date, the stock dividend with respect to the shares of Common
Stock acquired upon such Option exercise, notwithstanding the fact that such shares were not outstanding as of the close of business on the record date for such stock dividend. 

  
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 (b) Reorganization Events. 

(1) Definition. A “Reorganization Event” shall mean: (a) any merger or consolidation of the Company with or into another
entity as a result of which all of the Common Stock of the Company is converted into or exchanged for the right to receive cash, securities or other property or is cancelled, (b) any exchange of all of the Common Stock of the Company for cash,
securities or other property pursuant to a share exchange transaction or (c) any liquidation or dissolution of the Company. 
 (2)
Consequences of a Reorganization Event on Awards Other than Restricted Stock Awards. In connection with a Reorganization Event, the Board may take any one or more of the following actions as to all or any (or any portion of) outstanding
Awards other than Restricted Stock Awards on such terms as the Board determines: (i) provide that Awards shall be assumed, or substantially equivalent Awards shall be substituted, by the acquiring or succeeding corporation (or an affiliate
thereof); provided that, unless otherwise determined by the Board, such assumption or substitution of the Options shall comply with section 1.424-1 of the Treasury Regulations, (ii) upon written notice to
a Participant, provide that the Participant’s unexercised Awards will terminate immediately prior to the consummation of such Reorganization Event unless exercised by the Participant within a specified period following the date of such notice,
(iii) provide that outstanding Awards shall become exercisable, realizable, or deliverable, or restrictions applicable to an Award shall lapse, in whole or in part prior to or upon such Reorganization Event, (iv) in the event of a
Reorganization Event under the terms of which holders of Common Stock will receive upon consummation thereof a cash payment for each share surrendered in the Reorganization Event (the “Acquisition Price”), make or provide for a cash
payment to a Participant equal to the excess, if any, of (A) the Acquisition Price times the number of shares of Common Stock subject to the Participant’s Awards (to the extent the exercise price does not exceed the Acquisition Price) over
(B) the aggregate exercise price of all such outstanding Awards and any applicable tax withholdings, in exchange for the termination of such Awards, (v) provide that, in connection with a liquidation or dissolution of the Company, Awards
shall convert into the right to receive liquidation proceeds (if applicable, net of the exercise price thereof and any applicable tax withholdings) and (vi) any combination of the foregoing. In taking any of the actions permitted under this
Section 8(b), the Board shall not be obligated by the Plan to treat all Awards, all Awards held by a Participant, or all Awards of the same type, identically. 

For purposes of clause (i) above, an Option shall be considered assumed if, following consummation of the Reorganization Event, the
Option confers the right to purchase, for each share of Common Stock subject to the Option immediately prior to the consummation of the Reorganization Event, the consideration (whether cash, securities or other property) received as a result of the
Reorganization Event by holders of Common Stock for each share of Common Stock held immediately prior to the consummation of the Reorganization Event (and if holders were offered a choice of consideration, the type of consideration chosen by the
holders of a majority of the outstanding shares of Common Stock); provided, however, that if the consideration received as a result of the Reorganization Event is not solely common stock of the 

  
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acquiring or succeeding corporation (or an affiliate thereof), the Company may, with the consent of the acquiring or succeeding corporation, provide for the consideration to be received upon the
exercise of Options to consist solely of common stock of the acquiring or succeeding corporation (or an affiliate thereof) equivalent in value (as determined by the Board) to the per share consideration received by holders of outstanding shares of
Common Stock as a result of the Reorganization Event. 
 (3) Consequences of a Reorganization Event on Restricted Stock Awards. Upon
the occurrence of a Reorganization Event other than a liquidation or dissolution of the Company, the repurchase and other rights of the Company under each outstanding Restricted Stock Award shall inure to the benefit of the Company’s successor
and shall, unless the Board determines otherwise, apply to the cash, securities or other property which the Common Stock was converted into or exchanged for pursuant to such Reorganization Event in the same manner and to the same extent as they
applied to the Common Stock subject to such Restricted Stock Award. Upon the occurrence of a Reorganization Event involving the liquidation or dissolution of the Company, except to the extent specifically provided to the contrary in the instrument
evidencing any Restricted Stock Award or any other agreement between a Participant and the Company, all restrictions and conditions on all Restricted Stock Awards then outstanding shall automatically be deemed terminated or satisfied. 

9. General Provisions Applicable to Awards 

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

 (b) Documentation. Each Award shall be evidenced in such form (written, electronic or otherwise) as the Board shall determine. Each
Award may contain terms and conditions in addition to those set forth in the Plan. 
 (c) Board Discretion. Except as otherwise
provided by the Plan, each Award may be made alone or in addition or in relation to any other Award. The terms of each Award need not be identical, and the Board need not treat Participants uniformly. 

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

  
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 (e) Withholding. The Company shall not be obligated to deliver certificates, release from
forfeiture, otherwise recognize a Participant’s unrestricted ownership in an Award or the cash or property proceeds therefrom, until the Company satisfies all applicable federal, state, and local or other income and employment tax withholding
obligations. In its sole discretion, the Company may satisfy such withholding obligations by any of the following means or by a combination of such means: (i) causing the Participant to tender to the Company cash payment; (ii) withholding
cash from an Award settled in cash; (iii) withholding from amounts otherwise payable by the Company to the Participant, including but not limited to additional withholding on the Participant’s salary or wages, or from proceeds from the
sale of Common Stock issued pursuant to an Award; (iv) delivery of shares of Common Stock, including shares retained from the Award creating the tax obligation, valued at their Fair Market Value; provided, however, except as otherwise provided
by the Board, that the total tax withholding where stock is being used to satisfy such tax obligations cannot exceed the Company’s minimum statutory withholding obligations (based on minimum statutory withholding rates for federal and state tax
purposes, including payroll taxes, that are applicable to such supplemental taxable income), and provided, further, shares surrendered to satisfy tax withholding requirements cannot be subject to any repurchase, forfeiture, unfulfilled vesting or
other similar requirements; or (v) by such other method as determined by the Board. 
 (f) Amendment of Award. 

(1) The Board may amend, modify or terminate any outstanding Award, including but not limited to, substituting therefor another Award of the
same or a different type, changing the date of exercise or realization, and converting an Incentive Stock Option to a Nonstatutory Stock Option. The Participant’s consent to such action shall be required unless (i) the Board determines
that the action, taking into account any related action, would not materially and adversely affect the Participant’s rights under the Plan, (ii) the change is permitted under Section 8 hereof, or (iii) the change is to ensure
that an Option intended to qualify as an Incentive Stock Option qualifies as such. 
 (2) The Board may, without stockholder approval, amend
any outstanding Award granted under the Plan to provide an exercise price per share that is lower than the then-current exercise price per share of such outstanding Award. The Board may also, without stockholder approval, cancel any outstanding
award (whether or not granted under the Plan) and grant in substitution therefor new Awards under the Plan covering the same or a different number of shares of Common Stock and having an exercise price per share lower than the then-current exercise
price per share of the cancelled award.  
 (g) Conditions on Delivery of Stock.
The Company will not be obligated to deliver any shares of Common Stock pursuant to the Plan or to remove restrictions from shares previously delivered under the Plan until (i) all conditions of the Award have been met or removed to the
satisfaction of the Company, (ii) in the opinion of the Company’s counsel, all other legal matters in connection with the issuance and delivery of such shares have been satisfied, including any applicable securities laws and any applicable
stock exchange or stock market rules and regulations, and (iii) the Participant has executed and delivered to the Company such representations or agreements as the Company may consider appropriate to satisfy the requirements of any applicable
laws, rules or regulations. 

  
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 (h) Acceleration. The Board may at any time provide that any Award shall become
immediately exercisable in full or in part, free of some or all restrictions or conditions, or otherwise realizable in full or in part, as the case may be. 

10. Miscellaneous 
 (a) No Right To
Employment or Other Status. No person shall have any claim or right to be granted an Award, and the grant of an Award shall not be construed as giving a Participant the right to continued employment or any other relationship with the Company.
The Company expressly reserves the right at any time to dismiss or otherwise terminate its relationship with a Participant free from any liability or claim under the Plan, except as expressly provided in the applicable Award. 

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

(c) Effective Date and Term of Plan. The Plan shall become effective on the date on which it is adopted by the Board. No Awards shall be
granted under the Plan after the expiration of 10 years from the earlier of (i) the date on which the Plan was adopted by the Board or (ii) the date the Plan was approved by the Company’s stockholders, but Awards previously granted
may extend beyond that date. 
 (d) Amendment of Plan. The Board may amend, suspend or terminate the Plan or any portion thereof at
any time; provided that if at any time the approval of the Company’s stockholders is required as to any modification or amendment under Section 422 of the Code or any successor provision with respect to Incentive Stock Options, the Board
may not effect such modification or amendment without such approval. Unless otherwise specified in the amendment, any amendment to the Plan adopted in accordance with this Section 10(d) shall apply to, and be binding on the holders of, all
Awards outstanding under the Plan at the time the amendment is adopted, provided the Board determines that such amendment does not materially and adversely affect the rights of Participants under the Plan. 

(e) Authorization of Sub-Plans. The Board may from time to time establish one or more sub-plans under the Plan for purposes of satisfying applicable blue sky, securities or tax laws of various jurisdictions. The Board shall establish such sub-plans by adopting
supplements to this Plan containing (i) such limitations on the Board’s discretion under the Plan as the Board deems necessary or desirable or (ii) such additional terms and conditions not otherwise inconsistent with the Plan as the
Board shall deem necessary or desirable. All supplements adopted by the Board shall be deemed to be part of the Plan, but each supplement shall apply only to Participants within the affected jurisdiction and the Company shall not be required to
provide copies of any supplement to Participants in any jurisdiction which is not the subject of such supplement. 

  
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 (f) Compliance with Code Section 409A. Unless otherwise expressly provided for in an Award,
the Plan and Award will be interpreted to the greatest extent possible in a manner that makes the Plan and the Awards granted hereunder exempt from Section 409A of the Code, and, to the extent not so exempt, in compliance with Section 409A
of the Code. If the Board determines that any Award granted hereunder is not exempt from and is therefore subject to Section 409A of the Code, the Award will incorporate the terms and conditions necessary to avoid the consequences specified in
Section 409A(a)(1) of the Code, and to the extent an Award is silent on terms necessary for compliance, such terms as deemed necessary by the Board in its sole discretion are hereby incorporated by reference into the Award. Without limiting the
generality of the foregoing, if shares of Common Stock are publicly traded, and if a Participant holding an Award that constitutes “deferred compensation” under Section 409A of the Code is a “specified employee” for purposes
of Section 409A of the Code, no distribution or payment of any amount that is due because of a “separation from service” (as defined in Section 409A of the Code without regard to alternative definitions thereunder) will be issued
or paid before the date that is six (6) months following the date of such Participant’s “separation from service” or, if earlier, the date of the Participant’s death, unless such distribution or payment can be made in a
manner that complies with Section 409A of the Code, and any amounts so deferred will be paid in a lump sum on the day after such six (6) month period elapses, with the balance paid thereafter on the original schedule. The Company shall
have no liability to a Participant, or any other party, if an Award that is intended to be exempt from, or compliant with, Section 409A of the Code is not so exempt or compliant or for any other action taken by the Board. 

(g) Governing Law. The provisions of the Plan and all Awards made hereunder shall be governed by and interpreted in accordance with the
laws of the State of Delaware, excluding choice-of-law principles of the law of such state that would require the application of the laws of a jurisdiction other than
such state. 

  
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 UNUM THERAPEUTICS, INC. 

2015 STOCK INCENTIVE PLAN 

CALIFORNIA SUPPLEMENT 
 Pursuant
to Section 10(e) of the Plan, the Board has adopted this supplement for purposes of satisfying the requirements of Section 25102(o) of the California Law: 

Any Awards granted under the Plan to a Participant who is a resident of the State of California on the date of grant (a “California
Participant”) shall be subject to the following additional limitations, terms and conditions: 
 1. Additional Limitations on Options. 

(a) Minimum Vesting Rate. Except in the case of Options granted to California Participants who are officers, directors, managers,
consultants or advisors of the Company or its affiliates (which Options may become exercisable at whatever rate is determined by the Board), Options granted to California Participants shall become exercisable at a rate of not less than 20% per year
over five years from the date of grant; provided, that, such Options may be subject to such reasonable forfeiture conditions as the Board may choose to impose and which are not inconsistent with Section 260.140.41 of the
California Regulations. 
 (b) Minimum Exercise Price. The exercise price of Options granted to California Participants may not be
less than 85% of the Fair Market Value of the Common Stock on the date of grant in the case of a Nonstatutory Stock Option or less than 100% of the Fair Market Value of the Common Stock on the date of grant in the case of an Incentive Stock Option;
provided, however, that if the California Participant is a person who owns stock possessing more than 10% of the total combined voting power of all classes of stock of the Company or its parent or subsidiary corporations, the exercise
price shall be not less than 110% of the Fair Market Value of the Common Stock on the date of grant. 
 (c) Maximum Duration of
Options. No Options granted to California Participants shall have a term in excess of 10 years measured from the Option grant date. 

(d) Minimum Exercise Period Following Termination. Unless a California Participant’s employment is terminated for cause (as defined
by applicable law, the terms of any contract of employment between the Company and such Participant, or in the instrument evidencing the grant of such Participant’s Option), in the event of termination of employment of such Participant, such
Participant shall have the right to exercise an Option, to the extent that he or she was otherwise entitled to exercise such Option on the date employment terminated, as follows: (i) at least six months from the date of termination, if
termination was caused by such Participant’s death or “permanent and total disability” (within the meaning of Section 22(e)(3) of the Code) and (ii) at least 30 days from the date of termination, if termination was caused
other than by such Participant’s death or “permanent and total disability” (within the meaning of Section 22(e)(3) of the Code). 

 (e) Limitation on Repurchase Rights. If an Option granted to a California Participant
gives the Company the right to repurchase shares of Common Stock issued pursuant to the Plan upon termination of employment of such Participant, the terms of such repurchase right must comply with Section 260.140.41(k) of the California
Regulations. 
 2. Additional Limitations for Restricted Stock Awards. 

(a) Minimum Purchase Price. The purchase price for a Restricted Stock Award granted to a California Participant shall be not less than
85% of the Fair Market Value of the Common Stock at the time such Participant is granted the right to purchase shares under the Plan or at the time the purchase is consummated; provided, however, that if such Participant is a person
who owns stock possessing more than 10% of the total combined voting power or value of all classes of stock of the Company or its parent or subsidiary corporations, the purchase price shall be not less than 100% of the Fair Market Value of the
Common Stock at the time such Participant is granted the right to purchase shares under the Plan or at the time the purchase is consummated. 

(b) Limitation of Repurchase Rights. If a Restricted Stock Award granted to a California Participant gives the Company the right to
repurchase shares of Common Stock issued pursuant to the Plan upon termination of employment of such Participant, the terms of such repurchase right must comply with Section 260.140.42(h) of the California Regulations. 

3. Additional Limitations for Other Stock-Based Awards. The terms of all Awards granted to a California Participant under Section 7 of the Plan
shall comply, to the extent applicable, with Section 260.140.41 or Section 260.140.42 of the California Regulations. 
 4. Additional
Requirement to Provide Information to California Participants. The Company shall provide to each California Participant and to each California Participant who acquires Common Stock pursuant to the Plan, not less frequently than annually, copies
of annual financial statements (which need not be audited). The Company shall not be required to provide such statements to key employees whose duties in connection with the Company assure their access to equivalent information. 

5. Additional Limitations on Timing of Awards. No Award granted to a California Participant shall become exercisable, vested or realizable, as
applicable to such Award, unless the Plan has been approved by the holders of a majority of the Company’s outstanding voting securities within 12 months before or after the date the Plan was adopted by the Board. 

6. Additional Limitations Relating to Definition of Fair Market Value. For purposes of Section 1(b) and 2(a) of this supplement, “Fair Market
Value” shall be determined in a manner not inconsistent with Section 260.140.50 of the California Regulations. 
 7. Additional Restriction
Regarding Recapitalizations, Stock Splits, Etc. For purposes of Section 8 of the Plan, in the event of a stock split, reverse stock split, stock dividend, recapitalization, combination, reclassification or other distribution of the
Company’s securities, the number of securities allocated to each California Participant must be adjusted proportionately and without the receipt by the Company of any consideration from any California Participant. 

 UNUM THERAPEUTICS, INC. 

AMENDMENT NO. 1 TO 

2015 STOCK OPTION AND GRANT PLAN 

WHEREAS, the Board of Directors of Unum Therapeutics, Inc. (the “Company”) approved and adopted the 2015 Stock Option and
Grant Plan (the “Plan”) of the Company on January 29, 2015, and the stockholders of the Company approved and adopted the Plan on January 30, 2015; and 

WHEREAS, the Board of Directors and the stockholders of the Company have determined that it is in the best interest of the Company to amend
the Plan as set forth in this Amendment. 
 NOW, THEREFORE, the Plan is amended as follows: 

1. Amendment of the Plan. 

Section 4(a) of the Plan is hereby amended and restated in its entirety to read as follows: 

“Number of Shares. Subject to adjustment under Section 8, Awards may be made under the Plan for up to 6,508,000 shares of
common stock, $0.001 par value per share, of the Company (the “Common Stock”). If any Award expires or is terminated, surrendered or canceled without having been fully exercised, is forfeited in whole or in part (including as the result of
shares of Common Stock subject to such Award being repurchased by the Company at the original issuance price pursuant to a contractual repurchase right), or results in any Common Stock not being issued, the unused Common Stock covered by such Award
shall again be available for the grant of Awards under the Plan. Further, shares of Common Stock tendered to the Company by a Participant to exercise an Award shall be added to the number of shares of Common Stock available for the grant of Awards
under the Plan. However, in the case of Incentive Stock Options (as hereinafter defined), the foregoing provisions shall be subject to any limitations under the Code. Shares issued under the Plan may consist in whole or in part of authorized but
unissued shares or treasury shares. At no time while there is any Option (as defined below) outstanding and held by a Participant who was a resident of the State of California on the date of grant of such Option, shall the total number of shares of
Common Stock issuable upon exercise of all outstanding options and the total number of shares provided for under any stock bonus or similar plan or agreement of the Company exceed the applicable percentage as calculated in accordance with the
conditions and exclusions of Section 260.140.45 of the California Code of Regulations (the “California Regulations”), based on the shares of the Company which are outstanding at the time the calculation is made.” 

2. Miscellaneous. 
 2.01.
Effect. Except as amended hereby, the Plan shall remain in full force and effect. 
 2.02. Defined Terms. All
capitalized terms used but not specifically defined herein shall have the same meanings given such terms in the Plan unless the context clearly indicates or dictates a contrary meaning. 

 2.03. Governing Law. The provisions of the Plan and all Awards made hereunder shall
be governed by and interpreted in accordance with the laws of the State of Delaware, excluding choice-of-law principles of the law of such state that would require the
application of the laws of a jurisdiction other than such state. 
  

			
	ADOPTED BY BOARD OF DIRECTORS:	  	June 10, 2015
		
	APPROVED BY STOCKHOLDERS:	  	June 10, 2015

 UNUM THERAPEUTICS, INC. 

Nonstatutory Stock Option Agreement 

Granted Under 2015 Stock Incentive Plan 

1. Grant of Option. 
 This agreement
evidences the grant by Unum Therapeutics, Inc., a Delaware corporation (the “Company”), on , 201[         (the “Grant Date”) to [         , an
employee, consultant or director of the Company (the “Participant”), of an option to purchase, in whole or in part, on the terms provided herein and in the Company’s 2015 Stock Incentive Plan (the “Plan”), a total of
[         shares (the “Shares”) of common stock, $0.001 par value per share, of the Company (“Common Stock”) at $[         per Share. Unless
earlier terminated, this option shall expire at 5:00 p.m., Eastern time, on [                 (the “Final Exercise Date”). 

It is intended that the option evidenced by this agreement shall not be an incentive stock option as defined in Section 422 of the
Internal Revenue Code of 1986, as amended, and any regulations promulgated thereunder (the “Code”). Except as otherwise indicated by the context, the term “Participant”, as used in this option, shall be deemed to include any
person who acquires the right to exercise this option validly under its terms. 
 2. Vesting Schedule. 

Subject to Section 3(b) below, this option will become exercisable (“vest”) as to 25% of the original number of Shares on the
first anniversary of the Vesting Commencement Date (as defined below) and as to an additional 2.0833% of the original number of Shares at the end of each successive month following the first anniversary of the Vesting Commencement Date
until the fourth anniversary of the Vesting Commencement Date. In determining the number of vested Shares at the time of any exercise, the number of Shares shall be rounded down to the nearest whole Share. For purposes of this Agreement,
“Vesting Commencement Date” shall mean                     . 

The right of exercise shall be cumulative so that to the extent the option is not exercised in any period to the maximum extent permissible it
shall continue to be exercisable, in whole or in part, with respect to all Shares for which it is vested until the earlier of the Final Exercise Date or the termination of this option under Section 3 hereof or the Plan. 

3. Exercise of Option. 
 (a) Form of
Exercise. Each election to exercise this option shall be accompanied by a completed Notice of Stock Option Exercise in the form attached hereto as Exhibit A, signed by the Participant, and received by the Company at its principal office,
accompanied by this agreement, and payment in full in the manner provided in the Plan. The Participant may purchase less than the number of shares covered hereby, provided that no partial exercise of this option may be for any fractional share or
for fewer than ten whole shares. 

 (b) Time for Exercise of Certain Options. With respect to any option that constitutes a
plan for the deferral of compensation within the meaning of section 409A of the Code, such option may be exercised no earlier than the following events (all terms within the meaning of section 409A of the Code): (i) the Participant’s separation
from service; (ii) the Participant’s death or disability; or (iii) a change in the ownership or effective control of the Company, or in the ownership of a substantial portion of the assets of the Company. 

[A pre-determined schedule or fixed date may also be added as an exercise event.] 

(b) Continuous Relationship with the Company Required. Except as otherwise provided in this Section 3, this option may not be
exercised unless the Participant, at the time he or she exercises this option, is, and has been at all times since the Grant Date, an employee, officer or director of, or consultant or advisor to, the Company or any other entity the employees,
officers, directors, consultants, or advisors of which are eligible to receive option grants under the Plan (an “Eligible Participant”). 

(c) Termination of Relationship with the Company. If the Participant ceases to be an Eligible Participant for any reason, then, except
as provided in paragraphs (d) and (e) below, the right to exercise this option shall terminate three months after such cessation (but in no event after the Final Exercise Date), provided that this option shall be
exercisable only to the extent that the Participant was entitled to exercise this option on the date of such cessation. Notwithstanding the foregoing, if the Participant, prior to the Final Exercise Date, violates the
non-competition or confidentiality provisions of any employment contract, confidentiality and nondisclosure agreement or other agreement between the Participant and the Company, the right to exercise this
option shall terminate immediately upon such violation. 
 (d) Exercise Period Upon Death or Disability. If the Participant dies or
becomes disabled (within the meaning of Section 22(e)(3) of the Code) prior to the Final Exercise Date while he or she is an Eligible Participant and the Company has not terminated such relationship for “cause” as specified in
paragraph (e) below, this option shall be exercisable, within the period of one year following the date of death or disability of the Participant, by the Participant (or in the case of death by an authorized transferee), provided
that this option shall be exercisable only to the extent that this option was exercisable by the Participant on the date of his or her death or disability, and further provided that this option shall not be exercisable after the Final
Exercise Date. 
 (e) Termination for Cause. If, prior to the Final Exercise Date, the Participant’s employment or other
relationship with the Company is terminated by the Company for Cause (as defined below), the right to exercise this option shall terminate immediately upon the effective date of such termination of employment or other relationship. If, prior to the
Final Exercise Date, the Participant is given notice by the Company of the termination of his or her employment or other relationship by the Company for Cause, and the effective date of such employment or other termination is subsequent to the date
of the delivery of such notice, the right to exercise this option shall be suspended from the time of the delivery of such notice until the earlier of (i) such time as it is determined or otherwise agreed that the Participant’s employment
or other relationship shall not be terminated for Cause as provided in such notice or (ii) the effective date 

  
 -2- 

 
of such termination of employment or other relationship (in which case the right to exercise this option shall, pursuant to the preceding sentence, terminate immediately upon the effective date
of such termination of employment or other relationship). If the Participant is party to an employment, consulting or severance agreement with the Company that contains a definition of “cause” for termination of employment or other
relationship, “Cause” shall have the meaning ascribed to such term in such agreement. Otherwise, “Cause” shall mean willful misconduct by the Participant or willful failure by the Participant to perform his or her
responsibilities to the Company (including, without limitation, breach by the Participant of any provision of any employment, consulting, advisory, nondisclosure, non-competition or other similar agreement
between the Participant and the Company), as determined by the Company, which determination shall be conclusive. The Participant’s employment or other relationship shall be considered to have been terminated for “Cause” if the Company
determines, within 30 days after the Participant’s resignation, that termination for Cause was warranted. 
 4. Company Right of First Refusal.

 (a) Notice of Proposed Transfer. If the Participant proposes to sell, assign, transfer, pledge, hypothecate or otherwise dispose
of, by operation of law or otherwise (collectively, “transfer”) any Shares acquired upon exercise of this option, then the Participant shall first give written notice of the proposed transfer (the “Transfer Notice”) to the
Company. The Transfer Notice shall name the proposed transferee and state the number of such Shares the Participant proposes to transfer (the “Offered Shares”), the price per share and all other material terms and conditions of the
transfer. 
 (b) Company Right to Purchase. For 30 days following its receipt of such Transfer Notice, the Company shall have the
option to purchase all or part of the Offered Shares at the price and upon the terms set forth in the Transfer Notice. In the event the Company elects to purchase all or part of the Offered Shares, it shall give written notice of such election to
the Participant within such 30-day period. Within 10 days after his or her receipt of such notice, the Participant shall tender to the Company at its principal offices the certificate or certificates
representing the Offered Shares to be purchased by the Company, duly endorsed in blank by the Participant or with duly endorsed stock powers attached thereto, all in a form suitable for transfer of the Offered Shares to the Company. Promptly
following receipt of such certificate or certificates, the Company shall deliver or mail to the Participant a check in payment of the purchase price for such Offered Shares; provided that if the terms of payment set forth in the
Transfer Notice were other than cash against delivery, the Company may pay for the Offered Shares on the same terms and conditions as were set forth in the Transfer Notice; and provided further that any delay in making such payment
shall not invalidate the Company’s exercise of its option to purchase the Offered Shares. 
 (c) Shares Not Purchased By Company.
If the Company does not elect to acquire all of the Offered Shares, the Participant may, within the 30-day period following the expiration of the option granted to the Company under subsection (b) above,
transfer the Offered Shares which the Company has not elected to acquire to the proposed transferee, provided that such transfer shall not be on terms and conditions more favorable to the transferee than those contained in the Transfer
Notice. Notwithstanding any of the above, all Offered Shares transferred pursuant to this Section 4 shall remain subject to the right of first refusal set forth in this Section 4 and such transferee shall, as a condition to such transfer,
deliver to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of this Section 4. 

  
 -3- 

 (d) Consequences of Non-Delivery. After the time
at which the Offered Shares are required to be delivered to the Company for transfer to the Company pursuant to subsection (b) above, the Company shall not pay any dividend to the Participant on account of such Offered Shares or permit the
Participant to exercise any of the privileges or rights of a stockholder with respect to such Offered Shares, but shall, insofar as permitted by law, treat the Company as the owner of such Offered Shares. 

(e) Exempt Transactions. The following transactions shall be exempt from the provisions of this Section 4: 

(1) any transfer of Shares to or for the benefit of any spouse, child or grandchild of the Participant, or to a trust for their benefit; 

(2) any transfer pursuant to an effective registration statement filed by the Company under the Securities Act of 1933, as amended (the
“Securities Act”); and 
 (3) the sale of all or substantially all of the outstanding shares of capital stock of the Company
(including pursuant to a merger or consolidation); 
 provided, however, that in the case of a transfer pursuant to clause (1) above,
such Shares shall remain subject to the right of first refusal set forth in this Section 4 and such transferee shall, as a condition to such transfer, deliver to the Company a written instrument confirming that such transferee shall be bound by
all of the terms and conditions of this Section 4. 
 (f) Assignment of Company Right. The Company may assign its rights to
purchase Offered Shares in any particular transaction under this Section 4 to one or more persons or entities. 
 (g)
Termination. The provisions of this Section 4 shall terminate upon the earlier of the following events: 
 (1) the closing of the
sale of shares of Common Stock in an underwritten public offering pursuant to an effective registration statement filed by the Company under the Securities Act; or 

(2) the sale of all or substantially all of the outstanding shares of capital stock, assets or business of the Company, by merger,
consolidation, sale of assets or otherwise (other than a merger or consolidation in which all or substantially all of the individuals and entities who were beneficial owners of the Company’s voting securities immediately prior to such
transaction beneficially own, directly or indirectly, more than 75% (determined on an as-converted basis) of the outstanding securities entitled to vote generally in the election of directors of the resulting,
surviving or acquiring corporation in such transaction)”. 

  
 -4- 

 (h) No Obligation to Recognize Invalid Transfer. The Company shall not be required
(1) to transfer on its books any of the Shares which shall have been sold or transferred in violation of any of the provisions set forth in this Section 4, or (2) to treat as owner of such Shares or to pay dividends to any transferee
to whom any such Shares shall have been so sold or transferred. 
 (i) Legends. The certificate representing Shares shall bear a
legend substantially in the following form (in addition to, or in combination with, any legend required by applicable federal and state securities laws and agreements relating to the transfer of the Company securities): 

“The shares represented by this certificate are subject to a right of first refusal in favor of the Company, as provided in a certain
stock option agreement with the Company.” 
 5. Agreement in Connection with Initial Public Offering. 

The Participant agrees, in connection with the initial underwritten public offering of the Common Stock pursuant to a registration statement
under the Securities Act, (i) not to (a) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to
purchase, or otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any other securities of the Company or (b) enter into any swap or other agreement that transfers, in whole or in part, any of the economic
consequences of ownership of shares of Common Stock or other securities of the Company, whether any transaction described in clause (a) or (b) is to be settled by delivery of securities, in cash or otherwise, during the period beginning on the
date of the filing of such registration statement with the Securities and Exchange Commission and ending 180 days after the date of the final prospectus relating to the offering (plus up to an additional 34 days to the extent requested by the
managing underwriters for such offering in order to address Rule 2711(f) of the National Association of Securities Dealers, Inc. or any similar successor provision), and (ii) to execute any agreement reflecting clause (i) above as may be
requested by the Company or the managing underwriters at the time of such offering. The Company may impose stop-transfer instructions with respect to the shares of Common Stock or other securities subject to the foregoing restriction until the end
of the “lock-up” period. 
 6. Withholding. 

No Shares will be issued pursuant to the exercise of this option unless and until the Company satisfies all applicable federal, state, and
local or other income and employment tax withholding obligations as described in the Plan. 
 7. Transfer Restrictions. 

(a) This option may not be sold, assigned, transferred, pledged or otherwise encumbered by the Participant, either voluntarily or by operation
of law, except by will or the laws of descent and distribution, and, during the lifetime of the Participant, this option shall be exercisable only by the Participant. 

  
 -5- 

 (b) The Participant agrees that he or she will not transfer any Shares issued pursuant to the
exercise of this option unless the transferee, as a condition to such transfer, delivers to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of Section 4 and Section 5;
provided that such a written confirmation shall not be required with respect to (1) Section 4 after such provision has terminated in accordance with Section 4(g) or (2) Section 5 after the completion of the lock-up period in connection with the Company’s initial underwritten public offering. 
 8. Provisions of the
Plan. 
 This option is subject to the provisions of the Plan (including the provisions relating to amendments to the Plan), a copy of
which is furnished to the Participant with this option. 
 IN WITNESS WHEREOF, the Company has caused this option to be executed under its
corporate seal by its duly authorized officer. This option shall take effect as a sealed instrument. 
  

	
	UNUM THERAPEUTICS, INC.
	
	By:                                     
                                         
                  
	        Name:                             
                                         
          
	        Title:                             
                                         
             

  
 -6- 

 PARTICIPANT’S ACCEPTANCE 

The undersigned hereby accepts the foregoing option and agrees to the terms and conditions thereof. The undersigned hereby acknowledges
receipt of a copy of the Company’s 2015 Stock Incentive Plan. 
  

	
	PARTICIPANT:
	
	  

	
	Address:
	
	  

	
	  

  
 -7- 

 Exhibit A 

NOTICE OF STOCK OPTION EXERCISE 

Date:                     1 
 Unum Therapeutics, Inc. 

[INSERT ADDRESS] 
 Attention: Treasurer 

Dear Sir or Madam: 
 I am the holder of
                    2 Stock Option granted to me under the Unum Therapeutics, Inc. (the
“Company”) 2015 Stock Incentive Plan on                     3 for the purchase of
                    4 shares of Common Stock of the Company at a purchase price of
$                5 per share. 

I hereby exercise my option to purchase
                    6 shares of Common Stock (the “Shares”), for which I have enclosed
                    7 in the amount of
                    8. Please register my stock certificate as follows: 

 

			
	         Name(s):
	 	                                    
                            9
		
	         Address:
	 	  

		
	         Tax I.D. #:
	 	                                    
                        10

  
  

	1 	Enter the date of exercise. 

	2 	Enter either “an Incentive” or “a Nonstatutory”. 

	3 	Enter the date of grant. 

	4 	Enter the total number of shares of Common Stock for which the option was granted. 

	5 	Enter the option exercise price per share of Common Stock. 

	6 	Enter the number of shares of Common Stock to be purchased upon exercise of all or part of the option. 

	7 	Enter “cash”, “personal check” or if permitted by the option or Plan, “stock certificates No. XXXX and XXXX”. 

	8 	Enter the dollar amount (price per share of Common Stock times the number of shares of Common Stock to be purchased), or the number of shares tendered. Fair market value of shares tendered, together with cash or check,
must cover the purchase price of the shares issued upon exercise. 

	9	Enter name(s) to appear on stock certificate: (a) Your name only; (b) Your name and other name (i.e., John Doe and Jane Doe, Joint Tenants With Right of
Survivorship); or (c) In the case of a Nonstatutory option only, a Child’s name, with you as custodian (i.e., Jane Doe, Custodian for Tommy Doe). Note: There may be income and/or gift tax consequences of registering shares in a
Child’s name. 

	10	Social Security Number of Holder(s). 

  
 -8- 

 I represent, warrant and covenant as follows: 

1. I am purchasing the Shares for my own account for investment only, and not with a view to, or for sale in connection with, any distribution of the Shares in
violation of the Securities Act of 1933 (the “Securities Act”), or any rule or regulation under the Securities Act. 
 2. I have had such
opportunity as I have deemed adequate to obtain from representatives of the Company such information as is necessary to permit me to evaluate the merits and risks of my investment in the Company. 

3. I have sufficient experience in business, financial and investment matters to be able to evaluate the risks involved in the purchase of the Shares and to
make an informed investment decision with respect to such purchase. 
 4. I can afford a complete loss of the value of the Shares and am able to bear the
economic risk of holding such Shares for an indefinite period. 
 5. I understand that (i) the Shares have not been registered under the Securities Act
and are “restricted securities” within the meaning of Rule 144 under the Securities Act, (ii) the Shares cannot be sold, transferred or otherwise disposed of unless they are subsequently registered under the Securities Act or an
exemption from registration is then available; (iii) in any event, the exemption from registration under Rule 144 will not be available for at least one year and even then will not be available unless a public market then exists for the Common
Stock, adequate information concerning the Company is then available to the public, and other terms and conditions of Rule 144 are complied with; and (iv) there is now no registration statement on file with the Securities and Exchange
Commission with respect to any stock of the Company and the Company has no obligation or current intention to register the Shares under the Securities Act. 
  

	
	Very truly yours,
	
	  
 (Signature)

	

  
 -9- 

 UNUM THERAPEUTICS, INC. 

Incentive Stock Option Agreement 

Granted Under 2015 Stock Incentive Plan 

1. Grant of Option. 
 This agreement
evidences the grant by Unum Therapeutics, Inc., a Delaware corporation (the “Company”), on [          , 201[         (the “Grant
Date”) to [         , an employee of the Company (the “Participant”), of an option to purchase, in whole or in part, on the terms provided herein and in the Company’s 2015 Stock Incentive
Plan (the “Plan”), a total of [         shares (the “Shares”) of common stock, $0.001 par value per share, of the Company (“Common Stock”) at
$[         per Share. Unless earlier terminated, this option shall expire at 5:00 p.m., Eastern time, on [             (the “Final
Exercise Date”). 
 It is intended that the option evidenced by this agreement shall be an incentive stock option as defined in
Section 422 of the Internal Revenue Code of 1986, as amended, and any regulations promulgated thereunder (the “Code”). Except as otherwise indicated by the context, the term “Participant”, as used in this option, shall be
deemed to include any person who acquires the right to exercise this option validly under its terms. 
 2. Vesting Schedule. 

This option will become exercisable (“vest”) as to 25% of the original number of Shares on the first anniversary of the
Vesting Commencement Date (as defined below) and as to an additional 2.0833% of the original number of Shares at the end of each successive month following the first anniversary of the Vesting Commencement Date until the fourth
anniversary of the Vesting Commencement Date. In determining the number of vested Shares at the time of any exercise, the number of Shares shall be rounded down to the nearest whole Share. For purposes of this Agreement, “Vesting Commencement
Date” shall mean                         . 

The right of exercise shall be cumulative so that to the extent the option is not exercised in any period to the maximum extent permissible it
shall continue to be exercisable, in whole or in part, with respect to all Shares for which it is vested until the earlier of the Final Exercise Date or the termination of this option under Section 3 hereof or the Plan. 

3. Exercise of Option. 
 (a) Form of
Exercise. Each election to exercise this option shall be accompanied by a completed Notice of Stock Option Exercise in the form attached hereto as Exhibit A, signed by the Participant, and received by the Company at its principal office,
accompanied by this agreement, and payment in full in the manner provided in the Plan. The Participant may purchase less than the number of Shares covered hereby, provided that no partial exercise of this option may be for any fractional share or
for fewer than ten whole shares. 

 (b) Continuous Relationship with the Company Required. Except as otherwise provided in
this Section 3, this option may not be exercised unless the Participant, at the time he or she exercises this option, is, and has been at all times since the Grant Date, an employee or officer of, or consultant or advisor to, the Company or any
parent or subsidiary of the Company as defined in Section 424(e) or (f) of the Code (an “Eligible Participant”). 
 (c)
Termination of Relationship with the Company. If the Participant ceases to be an Eligible Participant for any reason, then, except as provided in paragraphs (d) and (e) below, the right to exercise this option shall terminate
three months after such cessation (but in no event after the Final Exercise Date), provided that this option shall be exercisable only to the extent that the Participant was entitled to exercise this option on the date of such
cessation. Notwithstanding the foregoing, if the Participant, prior to the Final Exercise Date, violates the non-competition or confidentiality provisions of any employment contract, confidentiality and
nondisclosure agreement or other agreement between the Participant and the Company, the right to exercise this option shall terminate immediately upon such violation. 

(d) Exercise Period Upon Death or Disability. If the Participant dies or becomes disabled (within the meaning of Section 22(e)(3)
of the Code) prior to the Final Exercise Date while he or she is an Eligible Participant and the Company has not terminated such relationship for “cause” as specified in paragraph (e) below, this option shall be exercisable, within
the period of one year following the date of death or disability of the Participant, by the Participant (or in the case of death by an authorized transferee), provided that this option shall be exercisable only to the extent that this
option was exercisable by the Participant on the date of his or her death or disability, and further provided that this option shall not be exercisable after the Final Exercise Date. 

(e) Termination for Cause. If, prior to the Final Exercise Date, the Participant’s employment is terminated by the Company for
Cause (as defined below), the right to exercise this option shall terminate immediately upon the effective date of such termination of employment. If, prior to the Final Exercise Date, the Participant is given notice by the Company of the
termination of his or her employment by the Company for Cause, and the effective date of such employment termination is subsequent to the date of delivery of such notice, the right to exercise this option shall be suspended from the time of the
delivery of such notice until the earlier of (i) such time as it is determined or otherwise agreed that the Participant’s employment shall not be terminated for Cause as provided in such notice or (ii) the effective date of such
termination of employment (in which case the right to exercise this option shall, pursuant to the preceding sentence, terminate upon the effective date of such termination of employment). If the Participant is party to an employment or severance
agreement with the Company that contains a definition of “cause” for termination of employment, “Cause” shall have the meaning ascribed to such term in such agreement. Otherwise, “Cause” shall mean willful misconduct by
the Participant or willful failure by the Participant to perform his or her responsibilities to the Company (including, without limitation, breach by the Participant of any provision of any employment, consulting, advisory, nondisclosure, non-competition or other similar agreement between the Participant and the Company), as determined by the Company, which determination shall be conclusive. The Participant’s employment shall be considered to
have been terminated for Cause if the Company determines, within 30 days after the Participant’s resignation, that termination for Cause was warranted. 

  
 - 2 - 

 4. Company Right of First Refusal. 

(a) Notice of Proposed Transfer. If the Participant proposes to sell, assign, transfer, pledge, hypothecate or otherwise dispose of, by
operation of law or otherwise (collectively, “transfer”) any Shares acquired upon exercise of this option, then the Participant shall first give written notice of the proposed transfer (the “Transfer Notice”) to the Company. The
Transfer Notice shall name the proposed transferee and state the number of such Shares the Participant proposes to transfer (the “Offered Shares”), the price per share and all other material terms and conditions of the transfer. 

(b) Company Right to Purchase. For 30 days following its receipt of such Transfer Notice, the Company shall have the option to purchase
all or part of the Offered Shares at the price and upon the terms set forth in the Transfer Notice. In the event the Company elects to purchase all or part of the Offered Shares, it shall give written notice of such election to the Participant
within such 30-day period. Within 10 days after his or her receipt of such notice, the Participant shall tender to the Company at its principal offices the certificate or certificates representing the Offered
Shares to be purchased by the Company, duly endorsed in blank by the Participant or with duly endorsed stock powers attached thereto, all in a form suitable for transfer of the Offered Shares to the Company. Promptly following receipt of such
certificate or certificates, the Company shall deliver or mail to the Participant a check in payment of the purchase price for such Offered Shares; provided that if the terms of payment set forth in the Transfer Notice were other than
cash against delivery, the Company may pay for the Offered Shares on the same terms and conditions as were set forth in the Transfer Notice; and provided further that any delay in making such payment shall not invalidate the
Company’s exercise of its option to purchase the Offered Shares. 
 (c) Shares Not Purchased By Company. If the Company does not
elect to acquire all of the Offered Shares, the Participant may, within the 30-day period following the expiration of the option granted to the Company under subsection (b) above, transfer the Offered
Shares which the Company has not elected to acquire to the proposed transferee, provided that such transfer shall not be on terms and conditions more favorable to the transferee than those contained in the Transfer Notice.
Notwithstanding any of the above, all Offered Shares transferred pursuant to this Section 4 shall remain subject to the right of first refusal set forth in this Section 4 and such transferee shall, as a condition to such transfer, deliver
to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of this Section 4. 

(d) Consequences of Non-Delivery. After the time at which the Offered Shares are required to be
delivered to the Company for transfer to the Company pursuant to subsection (b) above, the Company shall not pay any dividend to the Participant on account of such Offered Shares or permit the Participant to exercise any of the privileges or
rights of a stockholder with respect to such Offered Shares, but shall, insofar as permitted by law, treat the Company as the owner of such Offered Shares. 

  
 - 3 - 

 (e) Exempt Transactions. The following transactions shall be exempt from the provisions of
this Section 4: 
 (1) any transfer of Shares to or for the benefit of any spouse, child or grandchild of the Participant, or to a trust
for their benefit; 
 (2) any transfer pursuant to an effective registration statement filed by the Company under the Securities Act of 1933,
as amended (the “Securities Act”); and 
 (3) the sale of all or substantially all of the outstanding shares of capital stock of
the Company (including pursuant to a merger or consolidation); 
 provided, however, that in the case of a transfer pursuant to clause
(1) above, such Shares shall remain subject to the right of first refusal set forth in this Section 4 and such transferee shall, as a condition to such transfer, deliver to the Company a written instrument confirming that such transferee
shall be bound by all of the terms and conditions of this Section 4. 
 (f) Assignment of Company Right. The Company may assign
its rights to purchase Offered Shares in any particular transaction under this Section 4 to one or more persons or entities. 
 (g)
Termination. The provisions of this Section 4 shall terminate upon the earlier of the following events: 
 (1) the closing of the
sale of shares of Common Stock in an underwritten public offering pursuant to an effective registration statement filed by the Company under the Securities Act; or 

(2) the sale of all or substantially all of the outstanding shares of capital stock, assets or business of the Company, by merger,
consolidation, sale of assets or otherwise (other than a merger or consolidation in which all or substantially all of the individuals and entities who were beneficial owners of the Company’s voting securities immediately prior to such
transaction beneficially own, directly or indirectly, more than 75% (determined on an as-converted basis) of the outstanding securities entitled to vote generally in the election of directors of the resulting,
surviving or acquiring corporation in such transaction). 
 (h) No Obligation to Recognize Invalid Transfer. The Company shall not be
required (1) to transfer on its books any of the Shares which shall have been sold or transferred in violation of any of the provisions set forth in this Section 4, or (2) to treat as owner of such Shares or to pay dividends to any
transferee to whom any such Shares shall have been so sold or transferred. 
 (i) Legends. The certificate representing Shares shall
bear a legend substantially in the following form (in addition to, or in combination with, any legend required by applicable federal and state securities laws and agreements relating to the transfer of the Company securities): 

“The shares represented by this certificate are subject to a right of first refusal in favor of the Company, as provided in a certain
stock option agreement with the Company.” 

  
 - 4 - 

 5. Agreement in Connection with Initial Public Offering. 

The Participant agrees, in connection with the initial underwritten public offering of the Common Stock pursuant to a registration statement under the
Securities Act, (i) not to (a) offer, pledge, announce the intention to sell, sell, contract to sell, sell any option or contract to purchase, purchase any option or contract to sell, grant any option, right or warrant to purchase, or
otherwise transfer or dispose of, directly or indirectly, any shares of Common Stock or any other securities of the Company or (b) enter into any swap or other agreement that transfers, in whole or in part, any of the economic consequences of
ownership of shares of Common Stock or other securities of the Company, whether any transaction described in clause (a) or (b) is to be settled by delivery of securities, in cash or otherwise, during the period beginning on the date of the
filing of such registration statement with the Securities and Exchange Commission and ending 180 days after the date of the final prospectus relating to the offering (plus up to an additional 34 days to the extent requested by the managing
underwriters for such offering in order to address Rule 2711(f) of the National Association of Securities Dealers, Inc. or any similar successor provision), and (ii) to execute any agreement reflecting clause (i) above as may be requested
by the Company or the managing underwriters at the time of such offering. The Company may impose stop-transfer instructions with respect to the shares of Common Stock or other securities subject to the foregoing restriction until the end of the “lock-up” period. 
 6. Tax Matters. 

(a) Withholding. No Shares will be issued pursuant to the exercise of this option unless and until the Company satisfies all applicable
federal, state, and local or other income and employment tax withholding obligations as described in the Plan. 
 (b) Disqualifying
Disposition. If the Participant disposes of Shares acquired upon exercise of this option within two years from the Grant Date or one year after such Shares were acquired pursuant to exercise of this option, the Participant shall notify the
Company in writing of such disposition. 
 7. Transfer Restrictions. 

(a) This option may not be sold, assigned, transferred, pledged or otherwise encumbered by the Participant, either voluntarily or by operation
of law, except by will or the laws of descent and distribution, and, during the lifetime of the Participant, this option shall be exercisable only by the Participant. 

(b) The Participant agrees that he or she will not transfer any Shares issued pursuant to the exercise of this option unless the transferee, as
a condition to such transfer, delivers to the Company a written instrument confirming that such transferee shall be bound by all of the terms and conditions of Section 4 and Section 5; provided that such a written confirmation shall not be
required with respect to (1) Section 4 after such provision has terminated in accordance with Section 4(g) or (2) Section 5 after the completion of the lock-up period in connection
with the Company’s initial underwritten public offering. 
 8. Provisions of the Plan. 

This option is subject to the provisions of the Plan (including the provisions relating to amendments to the Plan), a copy of which is
furnished to the Participant with this option. 

  
 - 5 - 

 IN WITNESS WHEREOF, the Company has caused this option to be executed under its corporate seal by
its duly authorized officer. This option shall take effect as a sealed instrument. 
  

			
	UNUM THERAPEUTICS, INC.

 
			
		
	By:	 	  

		 	Name:                                     
                               
		 	Title:
                                         
                           

  
 - 6 - 

 PARTICIPANT’S ACCEPTANCE 

The undersigned hereby accepts the foregoing option and agrees to the terms and conditions thereof. The undersigned hereby acknowledges
receipt of a copy of the Company’s 2015 Stock Incentive Plan. 
  

	
	PARTICIPANT:
	
	  
 Address:

	
	  

	
	  

 Exhibit A 

NOTICE OF STOCK OPTION EXERCISE 

Date:                     1 
 Unum Therapeutics, Inc. 

[INSERT ADDRESS] 
 Attention: Treasurer 

Dear Sir or Madam: 
 I am the holder of
                2 Stock Option granted to me under the Unum Therapeutics, Inc. (the “Company”) 2015 Stock
Incentive Plan on                     3 for the purchase of
                    4 shares of Common Stock of the Company at a purchase price of
$                5 per share. 

I hereby exercise my option to purchase
                    6 shares of Common Stock (the “Shares”), for which I have enclosed
                    7 in the amount of
            8. Please register my stock certificate as follows: 

 

			
	         Name(s):
	 	                                    
                            9
		
	         Address:
	 	  

		
	         Tax I.D. #:
	 	                                    
                            10

 I represent, warrant and covenant as follows: 
  

 

	1 	Enter the date of exercise. 

	2 	Enter either “an Incentive” or “a Nonstatutory”. 

	3 	Enter the date of grant. 

	4 	Enter the total number of shares of Common Stock for which the option was granted. 

	5 	Enter the option exercise price per share of Common Stock. 

	6 	Enter the number of shares of Common Stock to be purchased upon exercise of all or part of the option. 

	7 	Enter “cash”, “personal check” or if permitted by the option or Plan, “stock certificates No. XXXX and XXXX”. 

	8 	Enter the dollar amount (price per share of Common Stock times the number of shares of Common Stock to be purchased), or the number of shares tendered. Fair market value of shares tendered, together with cash or check,
must cover the purchase price of the shares issued upon exercise. 

	9	Enter name(s) to appear on stock certificate: (a) Your name only; (b) Your name and other name (i.e., John Doe and Jane Doe, Joint Tenants With Right of
Survivorship); or (c) In the case of a Nonstatutory option only, a Child’s name, with you as custodian (i.e., Jane Doe, Custodian for Tommy Doe). Note: There may be income and/or gift tax consequences of registering shares in a
Child’s name. 

	10	Social Security Number of Holder(s). 

  
 - 8 - 

 1. I am purchasing the Shares for my own account for investment only, and not with a view to, or for sale in
connection with, any distribution of the Shares in violation of the Securities Act of 1933 (the “Securities Act”), or any rule or regulation under the Securities Act. 

2. I have had such opportunity as I have deemed adequate to obtain from representatives of the Company such information as is necessary to permit me to
evaluate the merits and risks of my investment in the Company. 
 3. I have sufficient experience in business, financial and investment matters to be able to
evaluate the risks involved in the purchase of the Shares and to make an informed investment decision with respect to such purchase. 
 4. I can afford a
complete loss of the value of the Shares and am able to bear the economic risk of holding such Shares for an indefinite period. 
 5. I understand that
(i) the Shares have not been registered under the Securities Act and are “restricted securities” within the meaning of Rule 144 under the Securities Act, (ii) the Shares cannot be sold, transferred or otherwise disposed of unless
they are subsequently registered under the Securities Act or an exemption from registration is then available; (iii) in any event, the exemption from registration under Rule 144 will not be available for at least one year and even then will not
be available unless a public market then exists for the Common Stock, adequate information concerning the Company is then available to the public, and other terms and conditions of Rule 144 are complied with; and (iv) there is now no
registration statement on file with the Securities and Exchange Commission with respect to any stock of the Company and the Company has no obligation or current intention to register the Shares under the Securities Act. 

Very truly yours, 
  

	
	  
 (Signature)

  
 - 9 -EX-10.5

 Exhibit 10.5 

UNUM THERAPEUTICS, INC. 

LOAN AND SECURITY AGREEMENT 

 This LOAN AND SECURITY AGREEMENT (the “Agreement”) is entered into as of January 19, 2017, by and
between PACIFIC WESTERN BANK, a California state chartered bank (“Bank”) and UNUM THERAPEUTICS, INC. (“Borrower”). 

RECITALS 
 Borrower wishes to obtain
credit from time to time from Bank, and Bank desires to extend credit to Borrower. This Agreement sets forth the terms on which Bank will advance credit to Borrower, and Borrower will repay the amounts owing to Bank. 

AGREEMENT 
 The parties agree as follows:

 1. DEFINITIONS AND CONSTRUCTION. 

1.1 Definitions. As used in this Agreement, all capitalized terms shall have the definitions set forth on Exhibit A. Any term used in
the Code and not defined herein shall have the meaning given to the term in the Code. 
 1.2 Accounting Terms. Any accounting term not
specifically defined on Exhibit A shall be construed in accordance with GAAP and all calculations shall be made in accordance with GAAP (except for noncompliance with FAS 123R in monthly reporting). The term “financial statements” shall
include the accompanying notes and schedules for audited financial statements. 
 2. LOAN AND TERMS OF PAYMENT. 

2.1 Credit Extensions. 

(a) Promise to Pay. Borrower promises to pay to Bank, in lawful money of the United States of America, the aggregate unpaid principal
amount of all Credit Extensions made by Bank to Borrower, together with interest on the unpaid principal amount of such Credit Extensions at rates in accordance with the terms hereof. 

(b) Term Loans. 

(i) Subject to and upon the terms and conditions of this Agreement, Bank agrees to make one (1) or more term loans to Borrower in
an aggregate principal amount not to exceed $15,000,000 (each a “Term Loan” and collectively the “Term Loans”). Borrower may request Term Loans at any time from the Closing Date through the Availability End Date. The proceeds of
the Term Loans shall be used for general working capital purposes, capital expenditures and/or general corporate purposes. 
 (ii)
Interest shall accrue from the date of each Term Loan at the rate specified in Section 2.3(a), and prior to the Availability End Date shall be payable monthly in arrears beginning on the 19th day of the month next following the such Term Loan,
and continuing on the same day of each month thereafter. Any Term Loans that are outstanding on the Availability End Date shall be payable in 24 equal monthly installments of principal, plus all accrued but unpaid interest, beginning on
February 19, 2019 and continuing on the same day of each month thereafter through the Term Loan Maturity Date, at which time all outstanding amounts due in connection with the Term Loans and any other outstanding amounts due under this
Agreement shall be immediately due and payable. Term Loans, once repaid, may not be reborrowed. Borrower may prepay any Term Loan without penalty or premium. 

(iii) When Borrower desires to obtain a Term Loan, Borrower shall notify Bank (which notice shall be irrevocable) by electronic mail or
facsimile transmission to be received no later than 3:30 p.m. Eastern time on the Business Day prior to the date on which the Term Loan is to be made. Such notice shall be substantially in the form of Exhibit C. The notice shall be signed by an
Authorized Officer. 

  
 1 

 2.2 Intentionally Omitted. 

2.3 Interest Rates, Payments, and Calculations. 

(a) Interest Rate. Except as set forth in Section 2.3(b), the Term Loans shall bear interest, on the outstanding daily balance
thereof, at a variable annual rate equal to the greater of (A) 0.25% above the Prime Rate then in effect, or (B) 3.75%. 
 (b)
Late Fee; Default Rate. If any payment is not made within 15 days after the date such payment is due, Borrower shall pay Bank a late fee equal to the lesser of (i) 5% of the amount of such unpaid amount or (ii) the maximum amount
permitted to be charged under applicable law. All outstanding Obligations shall bear interest, from and after the occurrence and during the continuance of an Event of Default, at a rate equal to 5 percentage points above the interest rate applicable
immediately prior to the occurrence of the Event of Default. 
 (c) Payments. Interest under the Term Loans shall be due and payable
in arrears on the 19th calendar day of each month during the term hereof. Bank shall, at its option, charge, when due, such interest, all Bank Expenses, and all Periodic Payments against any of Borrower’s deposit accounts (other than deposit
accounts exclusively used for payroll, payroll taxes and other employee wage and benefit payments to or for the benefit of Borrower’s or its Subsidiaries’ employees). 

(d) Computation. In the event the Prime Rate is changed from time to time hereafter, the applicable rate of interest hereunder shall be
increased or decreased, effective as of the day the Prime Rate is changed, by an amount equal to such change in the Prime Rate. All interest chargeable under the Loan Documents shall be computed on the basis of a 360 day year for the actual number
of days elapsed. 
 2.4 Crediting Payments. Except during the existence of an Event of Default, Bank shall credit a wire transfer of
funds, check or other item of payment to such deposit account or Obligation as Borrower specifies. After the occurrence and during the continuance of an Event of Default, Bank shall have the right, in its sole discretion, to immediately apply any
wire transfer of funds, check, or other item of payment Bank may receive to conditionally reduce Obligations, but such applications of funds shall not be considered a payment on account unless such payment is of immediately available federal funds
or unless and until such check or other item of payment is honored when presented for payment. Notwithstanding anything to the contrary contained herein, any wire transfer or payment received by Bank after 5:30 p.m. Eastern time shall be deemed to
have been received by Bank as of the opening of business on the immediately following Business Day. Whenever any payment to Bank under the Loan Documents would otherwise be due (except by reason of acceleration) on a date that is not a Business Day,
such payment shall instead be due on the next Business Day, and additional fees or interest, as the case may be, shall accrue and be payable for the period of such extension. 

2.5 Bank Expenses. On the Closing Date, Borrower shall pay to Bank all Bank Expenses incurred through the Closing Date, and, after the
Closing Date, all Bank Expenses, as and when they become due; provided however upon Borrower’s request Bank shall send Borrower an invoice therefor. 

2.6 Term. This Agreement shall become effective on the Closing Date and, subject to Section 12.7, shall continue in full force and
effect for so long as any Obligations (other than inchoate indemnification and reimbursement obligations) remain outstanding or Bank has any obligation to make Credit Extensions under this Agreement. Notwithstanding the foregoing, Bank shall have
the right in accordance with Section 9.1 to terminate its obligation to make Credit Extensions under this Agreement immediately and without notice upon the occurrence and during the continuance of an Event of Default. 

  
 2 

 3. CONDITIONS OF LOANS. 

3.1 Conditions Precedent to Closing. The agreement of Bank to enter into this Agreement on the Closing Date is subject to the condition
precedent that Bank shall have received, in form and substance satisfactory to Bank, each the following items and completed each of the following requirements: 

(a) this Agreement; 

(b) an officer’s certificate of Borrower with respect to incumbency and resolutions authorizing the execution and delivery of this
Agreement; 
 (c) a financing statement (Form UCC-1); 

(d) payment of the fees and Bank Expenses then due specified in Section 2.5, which may be debited from any of Borrower’s
accounts with Bank; 
 (e) current SOS Reports indicating that except for Permitted Liens, there are no other security interests or
Liens of record in the Collateral; 
 (f) current financial statements, including audited statements (or such other level required by
the Investment Agreement) for Borrower’s most recently ended fiscal year, together with an unqualified opinion (or an opinion qualified only for going concern so long as Borrower’s investors provide additional equity as needed), company
prepared consolidated balance sheets, income statements and statements of cash flows for the most recently ended month in accordance with Section 6.2, and such other updated financial information regarding Borrower as Bank may reasonably
request; 
 (g) current Compliance Certificate in accordance with Section 6.2; 

(h) evidence satisfactory to Bank that the insurance policies required by Section 6.5 hereof are in full force and effect, together
with appropriate evidence showing loss payable and additional insured clauses or endorsements in favor of Bank. 
 (i) a Borrower
Information Certificate; 
 (j) such other documents or certificates, and completion of such other matters, as Bank may reasonably
request; and 
 (k) Borrower shall have opened and funded not less than $50,000 in deposit accounts held with Bank. 

3.2 Conditions Precedent to all Credit Extensions. The obligation of Bank to make each Credit Extension, including the initial Credit
Extension, is contingent upon the Borrower’s compliance with Section 3.1 above on or prior to the Closing Date, and is further subject to the following conditions: 

(a) timely receipt by Bank of the Loan Advance/Paydown Request Form as provided in Section 2.1; 

(b) At all times prior to Borrower’s completion of Borrower’s initial public offering of its common stock, a Warrant to
Purchase Preferred Stock in substantially the form of Exhibit E-l attached hereto and at all times after Borrower’s completion of Borrower’s initial public offering of its common stock, a Warrant to Purchase Common Stock in substantially
the form of Exhibit E-2 attached hereto; 
 (c) Borrower shall be in compliance with Section 6.6 hereof; 

  
 3 

 (d) in Bank’s sole but reasonable discretion, there has not been a Material Adverse
Effect; and 
 (e) the representations and warranties contained in Section 5 shall be true and correct in all material respects
on and as of the date of such Loan Advance/Paydown Request Form and on the effective date of each Credit Extension as though made at and as of each such date, and no Event of Default shall have occurred and be continuing, or would exist after giving
effect to such Credit Extension (provided, however, that those representations and warranties expressly referring to another date shall be true and correct in all material respects as of such date). The making of each Credit Extension shall be
deemed to be a representation and warranty by Borrower on the date of such Credit Extension as to the accuracy of the facts referred to in this Section 3.2. 

4. CREATION OF SECURITY INTEREST. 
 4.1
Grant of Security Interest. Borrower grants and pledges to Bank a continuing security interest in the Collateral to secure prompt repayment of any and all Obligations and to secure prompt performance by Borrower of each of its covenants and
duties under the Loan Documents. Except for Permitted Liens or as disclosed in the Schedule, upon the filing of a financing statement in the jurisdiction of Borrower’s incorporation such security interest constitutes a valid, first priority
security interest in the presently existing Collateral, and will constitute a valid, first priority security interest in later-acquired Collateral. Borrower also hereby agrees not to sell, transfer, assign, mortgage, pledge, lease, grant a security
interest in, or encumber any of its Intellectual Property (other than with respect to Permitted Liens). Notwithstanding any termination of this Agreement or of any filings undertaken related to Bank’s rights under the Code, Bank’s Lien on
the Collateral shall remain in effect for so long as any Obligations (other than inchoate indemnification or reimbursement obligations) or are outstanding. 

4.2 Perfection of Security Interest. Borrower authorizes Bank to file at any time financing statements, continuation statements, and
amendments thereto that (i) either specifically describe the Collateral or describe the Collateral as all assets of Borrower of the kind pledged hereunder, and (ii) contain any other information required by the Code for the sufficiency of
filing office acceptance of any financing statement, continuation statement, or amendment, including whether Borrower is an organization, the type of organization and any organizational identification number issued to Borrower, if applicable.
Borrower shall have possession of the Collateral, except where expressly otherwise provided in this Agreement or where Bank chooses to perfect its security interest by possession in addition to the filing of a financing statement. Where Collateral
with a value in excess of $250,000 is in possession of a third party bailee, Borrower shall take such steps as Bank reasonably requests for Bank to (i) subject to Section 7.11 below, obtain an acknowledgment, in form and substance
reasonably satisfactory to Bank, of the bailee that the bailee holds such Collateral for the benefit of Bank, and (ii) obtain “control” of any Collateral consisting of investment property, deposit accounts, letter-of-credit rights or
electronic chattel paper (as such items and the term “control” are defined in Revised Article 9 of the Code) by causing the securities intermediary or depositary institution or issuing bank to execute a control agreement in form and
substance reasonably satisfactory to Bank. Borrower will not create any chattel paper without placing a legend on the chattel paper reasonably acceptable to Bank indicating that Bank has a security interest in the chattel paper. Borrower from time
to time may deposit with Bank specific cash collateral to secure specific Obligations; Borrower authorizes Bank to hold such specific balances in pledge and to decline to honor any drafts thereon or any request by Borrower or any other Person to pay
or otherwise transfer any part of such balances for so long as the specific Obligations are outstanding. Borrower shall take such other actions as Bank reasonably requests to perfect its security interests granted under this Agreement. 

5. REPRESENTATIONS AND WARRANTIES. 

Borrower represents and warrants as follows: 

5.1 Due Organization and Qualification. Borrower and each Subsidiary is duly existing under the laws of the state in which it is
organized and qualified and licensed to do business in any state in which the conduct of its business or its ownership of property requires that it be so qualified, except where the failure to do so would not reasonably be expected to cause a
Material Adverse Effect. 

  
 4 

 5.2 Due Authorization; No Conflict. The execution, delivery, and performance of the Loan
Documents are within Borrower’s powers, have been duly authorized, and are not in conflict with nor constitute a breach of any provision contained in Borrower’s Certificate of Incorporation or Bylaws, nor will they constitute an event of
default under any material agreement by which Borrower is bound. Borrower is not in default under any agreement by which it is bound, except to the extent such default would not reasonably be expected to cause a Material Adverse Effect. 

5.3 Collateral. Borrower has rights in or the power to transfer the Collateral, and its title to the Collateral is free and clear of
Liens, adverse claims, and restrictions on transfer or pledge except for Permitted Liens. Other than movable items of personal property such as laptop computers and inventory in transit, all Collateral having an aggregate book value in excess of
$250,000 is located solely in the Collateral States. All Inventory is in all material respects of good and merchantable quality, free from all material defects, except for Inventory for which adequate reserves have been made. Except as set forth in
the Schedule, none of the Borrower’s Cash is maintained or invested with a Person other than Bank or Bank’s affiliates. 
 5.4
Intellectual Property. Borrower is the sole owner of the intellectual property created or purchased by Borrower, except for (a) Permitted Licenses and (b) over-the-counter software that is commercially available to the public. To the
best of Borrower’s knowledge, each of the copyrights, trademarks and patents owned by Borrower and material to Borrower’s business is valid and enforceable, and no part of the intellectual property owned by Borrower that is material to
Borrower’s business has been judged invalid or unenforceable, in whole or in part, and no claim has been made to Borrower in writing alleging that any part of the intellectual property owned by Borrower that is material to Borrower’s
business violates the rights of any third party except to the extent such claim would not reasonably be expected to cause a Material Adverse Effect. 

5.5 Name; Location of Chief Executive Office. Except as disclosed in the Schedule, Borrower has not done business under any name other
than that specified on the signature page hereof, and its exact legal name is as set forth in the first paragraph of this Agreement. The chief executive office of Borrower is located at the address indicated in Section 10 hereof. 

5.6 Litigation. Except as set forth in the Schedule, there are no actions or proceedings pending by or against Borrower or any
Subsidiary before any court or administrative agency in which a likely adverse decision would reasonably be expected to have a Material Adverse Effect. 

5.7 No Material Adverse Change in Financial Statements. All consolidated and consolidating (if applicable) financial statements related
to Borrower and any Subsidiary that are delivered by Borrower to Bank fairly present in all material respects Borrower’s consolidated and consolidating (if applicable) financial condition as of the date thereof and Borrower’s consolidated
and consolidating (if applicable) results of operations for the period then ended (subject, in the case of unaudited financials to the absence of footnotes and year-end audit adjustments). There has not been a material adverse change in the
consolidated or in the consolidating (if applicable) financial condition of Borrower since the date of the most recent of such financial statements submitted to Bank by Borrower. 

5.8 Solvency, Payment of Debts. Borrower is able to pay its debts (including trade debts) as they mature; the fair saleable value of
Borrower’s assets (including goodwill minus disposition costs) exceeds the fair value of its liabilities; and Borrower is not left with unreasonably small capital after the transactions contemplated by this Agreement. 

5.9 Compliance with Laws and Regulations. Borrower and each Subsidiary have met the minimum funding requirements of ERISA with respect
to any employee benefit plans subject to ERISA. No event has occurred resulting from Borrower’s failure to comply with ERISA that is reasonably likely to result in Borrower’s incurring any liability that could have a Material Adverse
Effect. Borrower is not an “investment company” or a company “controlled” by an “investment company” within the meaning of the Investment Company Act of 1940. Borrower is not engaged principally, or as one of its
important activities, in the business of extending credit for the purpose of purchasing or carrying margin stock (within the meaning of Regulations T and U of the Board of Governors of the Federal Reserve System). Borrower has not violated any
statutes, laws, ordinances or rules applicable to it, the violation of which would reasonably be expected to have a Material Adverse Effect. Borrower and each Subsidiary have filed or caused to be filed all tax returns required to be filed by
Borrower or such 

  
 5 

 
Subsidiary, and have paid, or have made adequate provision for the payment of, all taxes reflected therein except those being contested in good faith with adequate reserves under GAAP or where
the failure to file such returns or pay such taxes would not reasonably be expected to have a Material Adverse Effect. 
 5.10
Subsidiaries. Borrower does not own any stock, partnership interest or other equity securities of any Person, except for Permitted investments. 

5.11 Government Consents. Borrower and each Subsidiary have obtained all consents, approvals and authorizations of, made all
declarations or filings with, and given all notices to, all governmental authorities that are necessary for the continued operation of Borrower’s business as currently conducted, except where the failure to do so would not reasonably be
expected to cause a Material Adverse Effect. 
 5.12 Inbound Licenses. Except as disclosed on the Schedule, Borrower is not a party
to, nor is bound by, any material license or other agreement important for the conduct of Borrower’s business that prohibits or otherwise restricts Borrower from granting a security interest in Borrower’s interest in such license or
agreement or any other property constituting Collateral and important for the conduct of Borrower’s business, other than this Agreement or the other Loan Documents (other than commercial off-the-shelf software). 

5.13 Full Disclosure. No representation, warranty or other statement made by Borrower in any certificate or written statement furnished
to Bank taken together with all such certificates and written statements furnished to Bank contains any untrue statement of a material fact or omits to state a material fact necessary in order to make the statements contained in such certificates or
statements not materially misleading in light of the circumstances in which they were made, it being recognized by Bank that the projections and forecasts provided by Borrower in good faith and based upon reasonable assumptions are not to be viewed
as facts and that actual results during the period or periods covered by any such projections and forecasts may materially differ from the projected or forecasted results. 

6. AFFIRMATIVE COVENANTS. 
 Borrower
covenants that, until payment in full of all outstanding Obligations (other than inchoate indemnification or reimbursement obligations), and for so long as Bank may have any commitment to make a Credit Extension hereunder, Borrower shall do all of
the following: 
 6.1 Good Standing and Government Compliance. Borrower shall maintain its and (except as permitted under
Section 7.3) each of its Subsidiaries’ corporate existence and good standing in the respective states of formation, shall maintain qualification and good standing in each other jurisdiction in which the failure to so qualify would
reasonably be expected to have a Material Adverse Effect, and shall furnish to Bank the organizational identification number issued to Borrower by the authorities of the state in which Borrower is organized, if applicable. Borrower shall meet, and
shall cause each Subsidiary to meet, the minimum funding requirements of ERISA with respect to any employee benefit plans subject to ERISA. Borrower shall comply, and shall cause each Subsidiary to comply, with all statutes, laws, ordinances and
government rules and regulations to which it is subject, and shall maintain, and shall cause each of its Subsidiaries to maintain, in force all licenses, approvals and agreements, in each case, the loss of which or failure to comply with which would
reasonably be expected to have a Material Adverse Effect. 
 6.2 Financial Statements, Reports, Certificates. Borrower shall deliver
to Bank: (i) as soon as available, but in any event within 30 days after the end of each calendar month, a company prepared consolidated balance sheet, income statement, and statement of cash flows covering Borrower’s operations during
such period, in a form reasonably acceptable to Bank and certified by a Responsible Officer; (ii) as soon as available, but in any event within 180 days after the end of Borrower’s fiscal year, audited (or such other level as is required
by the Investment Agreement) consolidated and consolidating (if applicable) financial statements of Borrower prepared in accordance with GAAP, consistently applied, together with an opinion which is either unqualified, qualified only for going
concern relating solely to Borrower’s liquidity position or otherwise consented to in writing by Bank on such financial statements of PricewaterhouseCoopers, any “Big Four” accounting firm, or any other independent certified public
accounting firm reasonably acceptable to Bank; (iii) annual financial plan (including budget and projections) approved by Borrower’s Board of Directors as soon as available but not later than 45 days after the end of each 

  
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fiscal year of Borrower during the term of this Agreement; (iv) if applicable, copies of all statements, reports and notices sent or made available generally by Borrower to its security
holders or to any holders of Subordinated Debt and all reports on Forms 10-K and 10-Q filed with the Securities and Exchange Commission (provided, that documents required to be delivered pursuant to this clause (iv) may be delivered
electronically and if so delivered, shall be deemed to have been delivered on the date on which Borrower provides a link thereto on Borrower’s website); (v) promptly upon receipt of notice thereof, a report of any legal actions pending or
threatened in writing against Borrower or any Subsidiary that could reasonably be expected to result in damages or costs to Borrower or any Subsidiary of $250,000 or more; (vi) promptly upon receipt by Borrower, each management letter prepared
by Borrower’s independent certified public accounting firm regarding Borrower’s management control systems; (vii) such budgets, sales projections, operating plans or other financial information generally prepared by Borrower in the
ordinary course of business as Bank may reasonably request from time to time; (viii) periodic informal clinical updates on any material developments as Borrower may determine with respect thereto, or when reasonably requested by Bank; and
(ix) promptly upon the execution thereof, any amendments to that certain Amended and Restated Exclusive License Agreement among NUS, St. Jude and Borrower dated as of August 1, 2014. 

(a) Within 30 days after the last day of each month, Borrower shall deliver to Bank with the monthly financial statements a Compliance
Certificate certified as of the last day of the applicable month and signed by a Responsible Officer in substantially the form of Exhibit D hereto. 

(b) As soon as possible and in any event within 3 Business Days after becoming aware of the occurrence or existence of an Event of
Default hereunder, a written statement of a Responsible Officer setting forth details of the Event of Default, and the action which Borrower has taken or proposes to take with respect thereto. 

(c) Bank (through any of its officers, employees, or agents) shall have the right, upon reasonable prior notice, from time to time at
reasonable times during Borrower’s usual business hours but no more than once a year (unless an Event of Default has occurred and is continuing), to inspect Borrower’s Books and to make copies thereof and to check, test, inspect, audit and
appraise the Collateral at Borrower’s expense in order to verify Borrower’s financial condition or the amount, condition of, or any other matter relating to, the Collateral. 

Borrower may deliver to Bank on an electronic basis any certificates, reports or information required pursuant to this Section 6.2, and
Bank shall be entitled to rely on the information contained in the electronic files, provided that Bank in good faith believes that the files were delivered by a Responsible Officer. Borrower shall include a submission date on any certificates and
reports to be delivered electronically. 
 6.3 Inventory and Equipment; Returns. Borrower shall keep all Inventory and Equipment in
good and merchantable condition (ordinary wear and tear and casualty damage excepted), free from all material defects except for Inventory and Equipment (i) sold in the ordinary course of business, and (ii) for which adequate reserves have
been made, in all cases in the United States and such other locations as to which Borrower gives prior written notice. Returns and allowances, if any, as between Borrower and its account debtors shall be on the same basis and in accordance with the
usual customary practices of Borrower, as they exist on the Closing Date. Borrower shall promptly notify Bank of all returns and recoveries and of all disputes and claims involving inventory having a book value of more than $100,000. 

6.4 Taxes. Borrower shall make, and cause each Subsidiary to make, due and timely payment or deposit of all material federal, state, and
local taxes, assessments, or contributions required of it by law, including, but not limited to, those laws concerning income taxes, F.I.C.A., F.U.T.A. and state disability, and will execute and deliver to Bank, on demand, proof reasonably
satisfactory to Bank indicating that Borrower or a Subsidiary has made such payments or deposits and any appropriate certificates attesting to the payment or deposit thereof; provided that Borrower or a Subsidiary need not make any payment if the
amount or validity of such payment is contested in good faith by appropriate proceedings and is reserved against (to the extent required by GAAP) by Borrower or such Subsidiary. 

6.5 Insurance. Borrower, at its expense, shall (i) keep the Collateral insured against loss or damage, and (ii) maintain
liability and other insurance, in each case as ordinarily insured against by other owners in businesses similar to Borrower’s of similar size and located in similar locations. All such policies of insurance shall be in such form, with such
companies, and in such amounts as reasonably satisfactory to Bank (it being 

  
 7 

 
acknowledged that the insurance maintained by Borrower as of the dale hereof is acceptable to Bank). All policies of property insurance shall contain a lender’s loss payable endorsement, in
a form reasonably satisfactory to Bank, showing Bank as lender’s loss payee. All liability insurance policies shall show, or have endorsements showing, Bank as an additional insured. Any such insurance policies shall specify that the insurer
must give at least 20 days’ notice to Bank before canceling its policy for any reason. Within 30 days of the Closing Date, Borrower shall cause to be furnished to Bank a copy of its policies including any endorsements covering Bank or showing
Bank as an additional insured. Upon Bank’s request, Borrower shall deliver to Bank certified copies of the policies of insurance and evidence of all premium payments. Proceeds payable under any casualty policy will, all Borrower’s option,
be payable to Borrower to replace the property subject to the claim, provided that any such replacement property shall be deemed Collateral in which Bank has been granted a first priority security interest (subject to Permitted Liens), provided that
if an Event of Default has occurred and is continuing, all proceeds payable under any such policy shall, at Bank’s option, be payable to Bank to be applied on account of the Obligations. 

6.6 Primary Depository. Borrower shall maintain substantially all its and Subsidiaries’ (other than the MSC Subsidiary’s)
depository and operating accounts with Bank. Notwithstanding the foregoing (i) if Borrower maintains at least $20,000,000 in Cash in depository and/or operating accounts with Bank or in investment accounts with Bank’s affiliates subject to
an account control agreement in favor of Bank, Borrower may maintain any excess amounts with another financial institution provided that Borrower, Bank, and any such financial institution shall have entered into an account control agreement with
respect to any such accounts, in form and substance satisfactory to Bank and (ii) Borrower shall be permitted to maintain the Silicon Valley Bank Cash Collateral Account at Silicon Valley Bank not subject to an account control agreement;
provided that the aggregate balance in the Silicon Valley Bank Cash Collateral Account shall not exceed $1,255,400 at any time. Borrower may transfer cash to the MSC Subsidiary so long as the MSC Investment Conditions have been met. 

6.7 Intentionally Omitted. 

6.8 Intentionally Omitted. 

6.9 Consent of Inbound Licensors. After entering into or becoming bound by any material inbound license or agreement, Borrower shall:
(i) on the next Compliance Certificate delivered to Bank after entering into such material license or agreement, provide written notice to Bank of the material terms of such license or agreement with a description of its likely impact on
Borrower’s business or financial condition; and (ii) at Bank’s reasonable request, in good faith use commercially reasonable efforts to obtain the consent of, or waiver by, any person whose consent or waiver is necessary for
Borrower’s interest in such licenses or contract rights (other than, in each case, for any license of Intellectual Property) to be deemed Collateral and for Bank to have a security interest in it that might otherwise be restricted by the terms
of the applicable license or agreement, whether now existing or entered into in the future, provided, however, that the failure to obtain any such consent or waiver shall not constitute a default under this Agreement. 

6.10 Creation/Acquisition of Subsidiaries. In the event any Borrower or any Subsidiary of any Borrower creates or acquires any
Subsidiary (other than the MSC Subsidiary), Borrower or such Subsidiary shall promptly notify Bank of such creation or acquisition, and Borrower or such Subsidiary shall take all actions reasonably requested by Bank to achieve any of the following
with respect to such “New Subsidiary” (defined as a Subsidiary formed after the Closing Date during the term of this Agreement): (i) to cause New Subsidiary to become either a co-Borrower hereunder, if such New
Subsidiary is organized under the laws of the United States, or a secured guarantor with respect to the Obligations; and (ii) to grant and pledge to Bank a perfected security interest in 100% of the stock, units or other evidence of ownership
held by Borrower or its Subsidiaries of any such New Subsidiary which is organized under the laws of the United States, and 65% of the stock, units or other evidence of ownership held by Borrower or its Subsidiaries of any such New Subsidiary which
is not organized under the laws of the United States. 
 6.11 Further Assurances. At any time and from time to time Borrower shall
execute and deliver such further instruments and take such further action as may reasonably be requested by Bank to effect the purposes of this Agreement. 

  
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 7. NEGATIVE COVENANTS. 

Borrower covenants and agrees that, so long as any credit hereunder shall be available and until the outstanding Obligations (other than
inchoate indemnification or reimbursement obligations) are paid in full or for so long as Bank may have any commitment to make any Credit Extensions, Borrower will not do any of the following without Bank’s prior written consent, which shall
not be unreasonably withheld: 
 7.1 Dispositions. Convey, sell, lease, license, transfer or otherwise dispose of (collectively, to
“Transfer”), or permit any of its Subsidiaries to Transfer, all or any part of its business or property, or move cash balances on deposit with Bank to accounts opened at another financial institution, other than Permitted Transfers. 

7.2 Change in Name, Location, Executive Office, or Executive Management; Change in Business; Change in Fiscal Year; Change in
Control. Change its name or the state of Borrower’s formation or relocate its chief executive office without 10 days prior written notification to Bank; replace or suffer the departure of its chief executive officer without delivering
written notification to Bank within 10 days; fail to appoint an interim replacement or fill a vacancy in the position of chief executive officer or chief financial officer for more than 60 consecutive days; suffer a change on its board of directors,
other than in connection with the initial public offering of Borrower’s common stock, which results in the failure of at least one partner of F-Prime, Atlas Venture and New Leaf, or their Affiliates, to serve as a voting member, or suffer the
resignation of one or more directors from its board of directors in anticipation of the Borrower’s insolvency, in either case without the prior written consent of Bank which may be withheld in Bank’s sole discretion; take action to
liquidate, wind up, or otherwise cease to conduct business in the ordinary course; engage in any business, or permit any of its Subsidiaries to engage in any business, other than or reasonably related or incidental to the businesses currently
engaged in by Borrower; change its fiscal year end; have a Change in Control. 
 7.3 Mergers or Acquisitions. Merge or consolidate, or
permit any of its Subsidiaries to merge or consolidate, with or into any other business organization (other than mergers or consolidations of a Subsidiary into another Subsidiary or into Borrower), or acquire, or permit any of its Subsidiaries to
acquire, all or substantially all of the capital stock or property of another Person except where (a) each of the following conditions is applicable: (i) the consideration paid in connection with such transactions (including assumption of
liabilities) does not in the aggregate exceed $500,000 during any fiscal year, (ii) no Event of Default has occurred, is continuing or would exist after giving effect to such transactions, (iii) such transactions do not result in a Change
in Control, and (iv) in transactions involving Borrower, Borrower is the surviving entity; or (b) the outstanding Obligations (other than inchoate indemnification or reimbursement obligations) are repaid in full concurrently with the closing of
any merger or consolidation of Borrower in which Borrower is not the surviving entity; provided, however, that Borrower shall not, without Bank’s prior written consent, enter into any binding contractual arrangement with any Person to attempt
to facilitate a merger or acquisition of Borrower, unless (i) no Event of Default exists when such agreement is entered into by Borrower, (ii) such agreement does not give such Person the right to claim any fee, payment or damages from any
parties, other than from Borrower or Borrower’s investors, in connection with a sale of Borrower’s stock or assets pursuant to or resulting from an assignment for the benefit of creditors, an asset turnover to Borrower’s creditors
(including, without limitation, Bank), foreclosure, bankruptcy or similar liquidation, and (iii) Borrower notifies Bank in advance of entering into such an agreement (provided, the failure to give such notification shall not be deemed a
material breach of this Agreement). 
 7.4 Indebtedness. Create, incur, assume, guarantee or be or remain liable with respect to any
Indebtedness, or permit any Subsidiary so to do, other than Permitted Indebtedness, or prepay any Indebtedness or take any actions which impose on Borrower an obligation to prepay any Indebtedness, except Indebtedness to Bank. 

7.5 Encumbrances. Create, incur, assume or allow any Lien with respect to its property, or assign or otherwise convey any right to
receive income, including the sale of any Accounts, or permit any of its Subsidiaries so to do, in each case, except for Permitted Liens, or covenant to any other Person (other than (i) the licensors of in-licensed property with respect to such
property or (ii) the lessors of specific equipment or Senders financing specific equipment with respect to such leased or financed equipment) that Borrower in the future will refrain from creating, incurring, assuming or allowing any Lien with
respect to any of Borrower’s property. 

  
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 7.6 Distributions. Pay any dividends or make any other distribution or payment on account
of or in redemption, retirement or purchase of any capital stock, except that Borrower may (i) repurchase the stock of former employees or directors pursuant to stock repurchase agreements in an aggregate amount not to exceed $250,000 in any
fiscal year, so long as an Event of Default does not exist prior to such repurchase or would not exist after giving effect to such repurchase, (ii) repurchase the stock of current or former employees or directors pursuant to stock repurchase
agreements in any amount where the consideration for the repurchase is the cancellation of indebtedness owed by such former employees or directors to Borrower regardless of whether an Event of Default exists, (iii) Borrower may convert any of
its convertible securities into other securities in accordance with the terms of such convertible securities or otherwise in exchange thereof, and (iv) Borrower may pay dividends solely in capital stock. 

7.7 Investments. Directly or indirectly acquire or own an Investment in, or make any Investment in or to any Person, or permit any of
its Subsidiaries so to do, other than Permitted Investments, or maintain or invest any of its investment property with a Person other than Bank or permit any Subsidiary to do so unless such Person has entered into a control agreement with Bank, in
form and substance reasonably satisfactory to Bank, or suffer or permit any Subsidiary to be a party to, or be bound by, an agreement that restricts such Subsidiary from paying dividends or otherwise distributing property to Borrower (other than the
Loan Documents). Notwithstanding the foregoing, if the MSC Investment Conditions have been met and no Event of Default shall exist, Borrower may make Investments in a wholly-owned corporation Subsidiary incorporated in Massachusetts for the purpose
of holding Investments as a Massachusetts security corporation under 830 CMR 63.38B.1 of the Massachusetts tax code and applicable regulations (as the same may be amended, modified or replaced from time to time) (the “MSC Subsidiary”). If
at any time after the incorporation of the MSC Subsidiary the MSC Investment Conditions are not met, then Borrower shall immediately cause the MSC Subsidiary to distribute to Borrower the lesser of (i) the assets required for the Borrower to
meet the MSC Investment Conditions or (ii) all assets held by the MSC Subsidiary for deposit into an account at Bank. Borrower shall not permit the MSC Subsidiary to make any Investments or hold any assets that would cause the MSC Subsidiary to
fail to qualify as a Massachusetts security corporation under 830 CMR 63.38B.1 of the Massachusetts tax code and applicable regulations (as the same may be amended, modified or replaced from time to time). 

7.8 Capitalized Expenditures. Make Capitalized Expenditures (a) for the 2017 fiscal year, in an aggregate amount exceeding
$5,000,000 and (b) for each fiscal year thereafter, in an aggregate amount exceeding 150% of the amount approved by Borrower’s Board of Directors for such year as set forth in the most recently approved operating plan delivered to Bank in
accordance with Section 6.2(iii) hereof, as such plan may be amended, supplemented or otherwise modified from time to time by Borrower’s Board of Directors. 

7.9 Transactions with Affiliates. Directly or indirectly enter into or permit to exist any material transaction with any Affiliate of
Borrower except for (i) transactions that are in the ordinary course of Borrower’s business, upon fair and reasonable terms that are no less favorable to Borrower than would be obtained in an arm’s length transaction with a
non-affiliated Person, (ii) the sale of Borrower’s equity securities in bona fide transactions with or the incurrence of Subordinated Debt to Borrower’s existing investors that do not result in a Change in Control,
(iii) transactions permitted pursuant to Section 7.3 and (iv) Permitted Transfers, Permitted Indebtedness and Permitted Investments. 

7.10 Subordinated Debt. Make any payment in respect of any Subordinated Debt, or permit any of its Subsidiaries to make any such
payment, except in compliance with the terms of such Subordinated Debt, or amend any provision affecting Bank’s rights contained in any documentation relating to the Subordinated Debt without Bank’s prior written consent. 

7.11 Inventory and Equipment. Store the Inventory or the Equipment of a book value in excess of (i) $1,000,000 with a third party
contract manufacturer or (ii) $250,000 with any other bailee, warehouseman, collocation facility or similar third party unless the third party has been notified of Bank’s security interest and Bank (a) has received an acknowledgment from
the third party that it is holding or will hold the Inventory or Equipment for Bank’s benefit or (b) is in possession of the warehouse receipt, where negotiable, covering such Inventory or Equipment. Except for Inventory sold in the
ordinary course of business and for movable items of personal property in the possession of Borrower’s employees, and except for such other locations as Bank may approve in writing, Borrower shall keep the Inventory and Equipment only at the
location set forth in Section 10 and such other locations of which Borrower gives Bank prior written notice and as to which Bank is able to take such actions as may be necessary to perfect its security interest or to obtain a bailee’s
acknowledgment of Bank’s rights in the Collateral. 

  
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 7.12 No Investment Company; Margin Regulation. Become or be controlled by an
“investment company,” within the meaning of the Investment Company Act of 1940, or become principally engaged in, or undertake as one of its important activities, the business of extending credit for the purpose of purchasing or carrying
margin stock, or use the proceeds of any Credit Extension for such purpose. 
 8. EVENTS OF DEFAULT. 

Any one or more of the following events shall constitute an Event of Default by Borrower under this Agreement: 

8.1 Payment Default. If Borrower fails to pay any of the Obligations when due unless such failure is caused by Bank’s failure to
debit such amounts from Borrower’s accounts when sufficient funds were contained therein; 
 8.2 Covenant Default. 

(a) If Borrower fails to perform any obligation under Sections 6.2 (financial reporting), 6.4 (taxes), 6.5 (insurance) or 6.6 (primary
accounts), or violates any of the covenants contained in Article 7 of this Agreement; or 
 (b) If Borrower fails or neglects to
perform or observe any other material term, provision, condition, covenant contained in this Agreement, in any of the Loan Documents, or in any other present or future agreement between Borrower and Bank and as to any default under such other term,
provision, condition or covenant that can be cured, has failed to cure such default within 10 days after Borrower receives notice thereof or any Responsible Officer of Borrower becomes aware thereof; provided, however, that if the default cannot by
its nature be cured within the 10 day period or cannot after diligent attempts by Borrower be cured within such 10 day period, and such default is likely to be cured within a reasonable time, then Borrower shall have an additional reasonable period
(which shall not in any case exceed 30 days) to attempt to cure such default, and within such reasonable time period the failure to have cured such default shall not be deemed an Event of Default but no Credit Extensions will be made; 

8.3 Material Adverse Change. If there occurs any circumstance or any circumstances which would reasonably be expected to have a Material
Adverse Effect; 
 8.4 Attachment. If any material portion of Borrower’s assets is attached, seized, subjected to a writ or
distress warrant, or is levied upon, or comes into the possession of any trustee, receiver or person acting in a similar capacity and such attachment, seizure, writ or distress warrant or levy has not been removed, discharged or rescinded within 10
days, or if Borrower is enjoined, restrained, or in any way prevented by court order from continuing to conduct all or any material part of its business affairs, or if a judgment or other claim becomes a lien or encumbrance upon any material portion
of Borrower’s assets, or if a notice of lien, levy, or assessment is filed of record with respect to any material portion of Borrower’s assets by the United States Government, or any department, agency, or instrumentality thereof, or by
any state, county, municipal, or governmental agency, and the same is not paid within ten days after Borrower receives notice thereof, provided that none of the foregoing shall constitute an Event of Default where such action or event is stayed or
an adequate bond has been posted pending a good faith contest by Borrower (provided that no Credit Extensions will be made during such cure period); 

8.5 Insolvency. If Borrower becomes insolvent, or if an Insolvency Proceeding is commenced by Borrower, or if an Insolvency Proceeding
is commenced against Borrower and is not dismissed or stayed within 45 days (provided that no Credit Extensions will be made prior to the dismissal of such Insolvency Proceeding); 

  
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 8.6 Other Agreements. If there is a default or other failure to perform in any agreement
to which Borrower is a party with a third party or parties (a) resulting in a right by such third party or parties, whether or not exercised, to accelerate the maturity of any Indebtedness in an amount in excess of $500,000, (b) in
connection with any lease of real property material to the conduct of Borrower’s business, if such default or failure to perform results in the right of another party to terminate such lease and the loss of such lease would reasonably be
expected to result in a Material Adverse Effect, or (c) that would reasonably be expected to have a Material Adverse Effect; 
 8.7
Judgments. If a final, uninsured judgment or judgments for the payment of money in an amount, individually or in the aggregate, of at least $500,000 shall be rendered against Borrower and shall remain unsatisfied and unstayed for a period of 10
days (provided that no Credit Extensions will be made prior to the satisfaction or stay of the judgment); or 
 8.8
Misrepresentations. If any material misrepresentation or material misstatement exists now or hereafter in any warranty or representation set forth herein or in any certificate delivered to Bank by any Responsible Officer pursuant to this
Agreement or to induce Bank to enter into this Agreement or any other Loan Document when made or deemed made. 
 8.9 Guaranty. If any
guaranty of all or a portion of the Obligations (a “Guaranty”) ceases for any reason to be in full force and effect, or any event of default occurs under any Guaranty or a security agreement securing any Guaranty (collectively, the
“Guaranty Documents”), or any guarantor revokes or purports to revoke a Guaranty, or any material misrepresentation or material misstatement exists in any warranty or representation set forth in any Guaranty Document or in any certificate
delivered to Bank in connection with any Guaranty Document when made or deemed made. 
 9. BANK’S RIGHTS AND REMEDIES. 

9.1 Rights and Remedies. Upon the occurrence and during the continuance of an Event of Default, Bank may, at its election, without
notice of its election and without demand, do any one or more of the following in accordance with applicable law, all of which are authorized by Borrower: 

(a) Declare all Obligations, whether evidenced by this Agreement, by any of the other Loan Documents, or otherwise, immediately due and
payable (provided that upon the occurrence of an Event of Default described in Section 8.5 (insolvency), all Obligations shall become immediately due and payable without any action by Bank); 

(b) Cease advancing money or extending credit to or for the benefit of Borrower under this Agreement or under any other agreement
between Borrower and Bank; 
 (c) Settle or adjust disputes and claims directly with account debtors for amounts, upon terms and in
whatever order that Bank reasonably considers advisable; 
 (d) Make such payments and do such acts as Bank considers necessary or
reasonable to protect its security interest in the Collateral. Borrower agrees to assemble the Collateral if Bank so requires, and to make the Collateral available to Bank as Bank may designate. Borrower authorizes Bank to enter the premises where
the Collateral is located, to take and maintain possession of the Collateral, or any part of it, and to pay, purchase, contest, or compromise any encumbrance, charge, or lien which in Bank’s determination appears to be prior or superior to its
security interest and to pay all expenses incurred in connection therewith. With respect to any of Borrower’s owned premises, Borrower hereby grants Bank a license to enter into possession of such premises and to occupy the same, without charge
by Borrower, in order to exercise any of Bank’s rights or remedies provided herein, at law, in equity, or otherwise; 
 (e) place
a “hold” on any account (other than deposit accounts exclusively used for payroll, payroll taxes and other employee wage and benefit payments to for the benefit of Borrower’s or its Subsidiaries’ employees) maintained with Bank
and/or deliver a notice of exclusive control, any entitlement order, or other directions or instructions pursuant to any control agreement or similar agreements providing control of any Collateral; 

  
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 (f) Set off and apply to the Obligations then due any and all (i) balances and
deposits of Borrower held by Bank, and (ii) indebtedness at any time owing to or for the credit or the account of Borrower held by Bank; 

(g) Ship, reclaim, recover, store, finish, maintain, repair, prepare for sale, advertise for sale, and sell (in the manner provided for
herein) the Collateral. Bank is hereby granted a license or other right, solely pursuant to the provisions of this Section 9.1, to use, without charge, Borrower’s labels, patents, copyrights, rights of use of any name, trade secrets, trade
names, trademarks, service marks, and advertising matter, or any property of a similar nature, as it pertains to the Collateral, in completing production of, advertising for sale, and selling any Collateral and, in connection with Bank’s
exercise of its rights under this Section 9.1, Borrower’s rights under all licenses and all franchise agreements shall inure to Bank’s benefit; 

(h) Sell the Collateral at either a public or private sale, or both, by way of one or more contracts or transactions, for cash or on
terms, in such manner and at such places (including Borrower’s premises) as Bank determines is commercially reasonable, and apply any proceeds to the Obligations in whatever manner or order Bank deems appropriate. Bank may sell the Collateral
without giving any warranties as to the Collateral. Bank may specifically disclaim any warranties of title or the like. This procedure will not be considered adversely to affect the commercial reasonableness of any sale of the Collateral. If Bank
sells any of the Collateral upon credit, Borrower will be credited only with payments actually made by the purchaser, received by Bank, and applied to the indebtedness of the purchaser. If the purchaser fails to pay for the Collateral, Bank may
resell the Collateral and Borrower shall be credited with the proceeds of the sale; 
 (i) Bank may credit bid and purchase at any
public sale; 
 (j) Apply for the appointment of a receiver, trustee, liquidator or conservator of the Collateral, without notice and
without regard to the adequacy of the security for the Obligations and without regard to the solvency of Borrower, any guarantor or any other Person liable for any of the Obligations; and 

(k) Any deficiency that exists after disposition of the Collateral as provided above will be paid immediately by Borrower. 

Bank may comply with any applicable state or federal law requirements in connection with a disposition of the Collateral and compliance will not be considered
adversely to affect the commercial reasonableness of any sale of the Collateral. 
 9.2 Power of Attorney. Effective only upon the
occurrence and during the continuance of an Event of Default, Borrower hereby irrevocably appoints Bank (and any of Bank’s designated officers, or employees) as Borrower’s true and lawful attorney to: (a) send requests for
verification of Accounts or notify account debtors of Bank’s security interest in the Accounts; (b) endorse Borrower’s name on any checks or other forms of payment or security that may come into Bank’s possession; (c) sign
Borrower’s name on any invoice or bill of lading relating to any Account, drafts against account debtors, schedules and assignments of Accounts, verifications of Accounts, and notices to account debtors; (d) dispose of any Collateral;
(e) make, settle, and adjust all claims under and decisions with respect to Borrower’s policies of insurance; (f) settle and adjust disputes and claims respecting the accounts directly with account debtors, for amounts and upon terms
which Bank determines to be reasonable; and (g) file, in its sole discretion, one or more financing or continuation statements and amendments thereto, relative to any of the Collateral; provided Bank may exercise such power of attorney to sign
the name of Borrower on any of the documents described in clause (g) above, regardless of whether an Event of Default has occurred. The appointment of Bank as Borrower’s attorney in fact, and each and every one of Bank’s rights and
powers, being coupled with an interest, is irrevocable until all of the Obligations (other than inchoate indemnification or reimbursement obligations) have been fully repaid and performed and Bank’s obligation to provide advances hereunder is
terminated. 
 9.3 Accounts Collection. At any time after the occurrence and during the continuation of an Event of Default, Bank may
notify any Person owing funds to Borrower of Bank’s security interest in such funds and verify the amount of such Account. After the occurrence and during the continuance of an Event of Default, Borrower shall collect all amounts owing to
Borrower for Bank, receive in trust all payments as Bank’s trustee, and immediately deliver such payments to Bank in their original form as received from the account debtor, with proper endorsements for deposit. 

  
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 9.4 Bank Expenses. If Borrower fails to timely pay any amounts or furnish any required
proof of payment due to third persons or entities, as required under the terms of this Agreement, then Bank may do any or all of the following after reasonable notice to Borrower: (a) make payment of the same or any part thereof; or
(b) obtain and maintain insurance policies of the type discussed in Section 6.5 of this Agreement, and take any action with respect to such policies as Bank reasonably deems prudent. Any amounts so paid or deposited by Bank shall
constitute Bank Expenses, shall be immediately due and payable, and shall bear interest at the then applicable rate hereinabove provided, and shall be secured by the Collateral. Any payments made by Bank shall not constitute an agreement by Bank to
make similar payments in the future or a waiver by Bank of any Event of Default under this Agreement. 
 9.5 Bank’s Liability for
Collateral. Bank has no obligation to clean up or otherwise prepare the Collateral for sale. All risk of loss, damage or destruction of the Collateral shall be borne by Borrower. 

9.6 No Obligation to Pursue Others. Bank has no obligation to attempt to satisfy the Obligations by collecting them from any other
person liable for them and Bank may release, modify or waive any collateral provided by any other Person to secure any of the Obligations, all without affecting Bank’s rights against Borrower. Borrower waives any right it may have to require
Bank to pursue any other Person for any of the Obligations. 
 9.7 Remedies Cumulative. Bank’s rights and remedies under this
Agreement, the Loan Documents, and all other agreements shall be cumulative. Bank shall have all other rights and remedies not inconsistent herewith as provided under the Code, by law, or in equity. No exercise by Bank of one right or remedy shall
be deemed an election, and no waiver by Bank of any Event of Default on Borrower’s part shall be deemed a continuing waiver. No delay by Bank shall constitute a waiver, election, or acquiescence by it. No waiver by Bank shall be effective
unless made in a written document signed on behalf of Bank and then shall be effective only in the specific instance and for the specific purpose for which it was given. Borrower expressly agrees that this Section 9.7 may not be waived or
modified by Bank by course of performance, conduct, estoppel or otherwise. 
 9.8 Demand; Protest. Except as otherwise provided in
this Agreement, Borrower waives demand, protest, notice of protest, notice of default or dishonor, notice of payment and nonpayment and any other notices relating to the Obligations. 

10. NOTICES. 
 Unless otherwise provided in
this Agreement, all notices or demands by any party relating to this Agreement or any other agreement entered into in connection herewith shall be in writing and (except for financial statements and other informational documents which may be sent by
first-class mail, postage prepaid) shall be personally delivered or sent by a recognized overnight delivery service, certified mail, postage prepaid, return receipt requested, or by telefacsimile to Borrower or to Bank, as the case may be, at its
addresses set forth below: 
  

			
	 If to Borrower:
	  	 UNUM THERAPEUTICS, INC.
 Attn: Christiana
Stamoulis
 200 Cambridge Park Drive, Suite 3100
 Cambridge, MA
02140

		
	 If to Bank:
	  	 Pacific Western Bank
 406 Blackwell Street,
Suite 240
 Durham, North Carolina 27701
 Attn: Loan Operations
Manager
 FAX: XXX-XXX-XXXX

		
	 with a copy to:
	  	 Pacific Western Bank
 131 Oliver Street, 2nd Floor
 Boston, MA 02110

Attn: Scott Hansen
 FAX: XXX-XXX-XXXX

  
 14 

 Boston, MA 02110 

Attn: Scott Hansen 
 FAX:
XXX-XXX-XXXX 
 The parties hereto may change the address at which they are to receive notices hereunder, by notice in writing in the
foregoing manner given to the other. 
 11. CHOICE OF LAW AND VENUE; JURY TRIAL WAIVER. 

This Agreement shall be governed by, and construed in accordance with, the internal laws of the State of North Carolina, without regard to principles of
conflicts of law. Jurisdiction shall lie in the State of North Carolina. Ail disputes, controversies, claims, actions and similar proceedings arising with respect to Borrower’s account or any related agreement or transaction shall be brought in
the General Court of Justice of North Carolina sitting in Durham County, North Carolina or the United States District Court for the Middle District of North Carolina, except as provided below with respect to arbitration of such matters. BANK AND
BORROWER EACH ACKNOWLEDGE THAT THE RIGHT TO TRIAL BY JURY IS A CONSTITUTIONAL ONE, BUT THAT IT MAY BE WAIVED. EACH OF THEM, AFTER CONSULTING OR HAVING HAD THE OPPORTUNITY TO CONSULT, WITH COUNSEL OF THEIR CHOICE, KNOWINGLY, VOLUNTARILY AND
INTENTIONALLY WAIVES ANY RIGHT ANY OF THEM MAY HAVE TO A TRIAL BY JURY IN ANY LITIGATION BASED UPON OR ARISING OUT OF THIS AGREEMENT OR ANY RELATED INSTRUMENT OR LOAN DOCUMENT OR ANY OF THE TRANSACTIONS CONTEMPLATED BY THIS AGREEMENT OR ANY COURSE
OF CONDUCT, DEALING, STATEMENTS (WHETHER ORAL OR WRITTEN), OR ACTION OF ANY OF THEM. THESE PROVISIONS SHALL NOT BE DEEMED TO HAVE BEEN MODIFIED IN ANY RESPECT OR RELINQUISHED BY BANK OR BORROWER, EXCEPT BY A WRITTEN INSTRUMENT EXECUTED BY EACH OF
THEM, If the jury waiver set forth in this Section 11 is not enforceable, then any dispute, controversy, claim, action or similar proceeding arising out of or relating to this Agreement, the Loan Documents or any of the transactions
contemplated therein shall be settled by final and binding arbitration held in Durham County, North Carolina in accordance with the then current Commercial Arbitration Rules of the American Arbitration Association by one arbitrator appointed in
accordance with those rules. The arbitrator shall apply North Carolina law to the resolution of any dispute, without reference to rules of conflicts of law or rules of statutory arbitration. Judgment upon any award resulting from arbitration may be
entered into and enforced by any state or federal court having jurisdiction thereof. Notwithstanding the foregoing, the parties may apply to any court of competent jurisdiction for preliminary or interim equitable relief, or to compel arbitration in
accordance with this Section. The costs and expenses of the arbitration, including without limitation, the arbitrator’s fees and expert witness fees, and reasonable attorneys’ fees, incurred by the parties to the arbitration may be awarded
to the prevailing party, in the discretion of the arbitrator, or may be apportioned between the parties in any manner deemed appropriate by the arbitrator. Unless and until the arbitrator decides that one party is to pay for all (or a share) of such
costs and expenses, both parties shall share equally in the payment of the arbitrator’s fees as and when billed by the arbitrator. 
 12. GENERAL
PROVISIONS. 
 12.1 Successors and Assigns. This Agreement shall bind and inure to the benefit of the respective successors and
permitted assigns of each of the parties and shall bind all persons who become bound as a debtor to this Agreement; provided, however, that neither this Agreement nor any rights hereunder may be assigned by Borrower without Bank’s prior written
consent, which consent may be granted or withheld in Bank’s sole discretion. Bank shall have the right without the consent of or notice to Borrower to sell, assign, transfer, negotiate, or grant participation in all or any part of, or any
interest in, Bank’s obligations, rights and benefits hereunder. Notwithstanding the foregoing, unless an Event of Default shall have occurred and be continuing, Bank shall not assign the Agreement or sell a participation therein to any vulture
debt fund or direct competitor of Borrower as determined by the mutual agreement of Borrower and Bank. 
 12.2 Indemnification.
Borrower shall defend, indemnify and hold harmless Bank and its officers, employees, and agents against: (a) all obligations, demands, claims, and liabilities claimed or asserted by any other party in connection with the transactions
contemplated by this Agreement; and (b) all losses or Bank Expenses in any way suffered, incurred, or paid by Bank, its officers, employees and agents as a result of or in any way arising out of, following, or consequential to transactions
between Bank and Borrower whether under this Agreement, or otherwise (including without limitation reasonable attorneys fees and expenses), except, in each case, for claims, losses, obligations or liabilities caused by Bank’s gross negligence
or willful misconduct. 

  
 15 

 12.3 Time of Essence. Time is of the essence for the performance of all obligations set
forth in this Agreement. 
 12.4 Severability of Provisions. Each provision of this Agreement shall be severable from every other
provision of this Agreement for the purpose of determining the legal enforceability of any specific provision. 
 12.5 Amendments in
Writing, Integration. All amendments to or terminations of this Agreement or the other Loan Documents must be in writing. All prior agreements, understandings, representations, warranties, and negotiations between the parties hereto with respect
to the subject matter of this Agreement and the other Loan Documents, if any, are merged into this Agreement and the Loan Documents. 

12.6 Counterparts. This Agreement may be executed in any number of counterparts and by different parties on separate counterparts, each
of which, when executed and delivered, shall be deemed to be an original, and all of which, when taken together, shall constitute but one and the same Agreement. Executed copies of the signature pages of this Agreement sent by facsimile or
transmitted electronically in Portable Document Format (“PDF”), or any similar format, shall be treated as originals, fully binding and with Full legal force and effect, and the parties waive any rights they may have to object to such
treatment. 
 12.7 Survival. All covenants, representations and warranties made in this Agreement shall continue in full force and
effect so long as any Obligations (other than inchoate indemnification or reimbursement obligations) remain outstanding or Bank has any obligation to make any Credit Extension to Borrower. The obligations of Borrower to indemnify Bank with respect
to the expenses, damages, losses, costs and liabilities described in Section 12.2 shall survive until all applicable statute of limitations periods with respect to actions that may be brought against Bank have run. 

12.8 Confidentiality. In handling any confidential information, Bank and Borrower and all employees and agents of each such party shall
exercise the same degree of care that such party exercises with respect to its own proprietary information of the same types to maintain the confidentiality of any non-public information thereby received or received pursuant to this Agreement except
that disclosure of such information may be made (i) in the case of Bank, to the subsidiaries or Affiliates of Bank or Borrower in connection with their present or prospective business relations with Borrower, (ii) in the case of Bank, to
prospective transferees or purchasers of any interest in the Credit Extensions, provided that they have entered into a comparable confidentiality agreement in favor of Borrower and have delivered a copy to Borrower, (iii) as required by law,
regulations, rule or order, subpoena, judicial order or similar order, (iv) in the case of Bank, as may be required in connection with the examination, audit or similar investigation of Bank and (v) as Bank may determine in connection with
the enforcement of any remedies hereunder. Confidential information hereunder shall not include information that either: (a) is in the public domain or in the knowledge or possession of the receiving party when disclosed to such party, or
becomes part of the public domain after disclosure to such receiving party through no fault of such receiving party; or (b) is disclosed to such receiving party by a third party under no obligation of confidentiality to Borrower or Bank (as
applicable). 
 [Balance of Page Intentionally Left Blank] 

  
 16 

 IN WITNESS WHEREOF, the parties hereto have caused this Agreement to be executed as of the date first above
written. 
  

			
	UNUM THERAPEUTICS, INC.
		
	By:	 	/s/ Charles Wilson
	Name: Charles Wilson
	Title: President & CEO
		 	

  

			
	PACIFIC WESTERN BANK
		
	By:	 	/s/ Scott Hansen
	Name: Scott Hansen
	Title: Vice President

 [Signature Page to Loan and Security Agreement] 

 EXHIBIT A 

DEFINITIONS 
 “Accounts” means all presently
existing and hereafter arising accounts, contract rights, payment intangibles and all other forms of obligations owing to Borrower arising out of the sale or lease of goods (including, without limitation, the licensing of software and other
technology) or the rendering of services by Borrower and any and all credit insurance, guaranties, and other security therefor, as well as all merchandise returned to or reclaimed by Borrower and Borrower’s Books relating to any of the
foregoing. 
 “Affiliate” means, with respect to any Person, any Person that owns or controls directly or indirectly such Person, any Person that
controls or is controlled by or is under common control with such Person, and each of such Person’s senior executive officers, directors, and general partners. 

“Authorized Officer” means someone designated as such in the corporate resolution provided by Borrower to Bank in which this Agreement and the
transactions contemplated hereunder are authorized by Borrower’s board of directors. If Borrower provides subsequent corporate resolutions to Bank after the Closing Date, the individual(s) designated as “Authorized Officer(s)” in the
most-recently provided resolution shall be the only “Authorized Officers” for purposes of this Agreement. 
 “Availability End Date”
means January 19, 2019. 
 “Bank Expenses” means all reasonable and documented costs or expenses (including reasonable and documented
attorneys’ fees and expenses, whether generated in-house or by outside counsel) incurred in connection with the preparation, negotiation, administration, and enforcement of the Loan Documents; reasonable Collateral audit fees; and Bank’s
reasonable attorneys’ fees and expenses (whether generated in-house or by outside counsel) incurred in amending, enforcing or defending the Loan Documents (including fees and expenses of appeal), incurred before, during and after an Insolvency
Proceeding, whether or not suit is brought. 
 “Borrower’s Books” means all of Borrower’s books and records including: ledgers; records
concerning Borrower’s assets or liabilities, the Collateral, business operations or financial condition; and all computer programs, or tape files, and the equipment, containing such information. 

“Business Day” means any day that is not a Saturday, Sunday, or other day on which banks in the State of North Carolina are authorized or required
to close. 
 “Capitalized Expenditures” means current period unfinanced cash expenditures that are capitalized and amortized over a period of time
in accordance with GAAP, including but not limited to capitalized cash expenditures for capital equipment, capitalized manufacturing and labor costs as they relate to inventory, and software development. 

“Cash” means unrestricted cash and cash equivalents. 

“Change in Control” shall mean a transaction other than (i) an IPO or any follow-on public offering or (ii) a bona fide private equity
financing or series of financings on terms reasonably acceptable to Borrower’s board of directors so long as at least one partner of F-Prime, Atlas Venture and New Leaf serve as voting members of Borrower’s board of directors, or otherwise
reasonably acceptable to Bank, in which any “person” or “group” (within the meaning of Section 13(d) and 14(d)(2) of the Securities Exchange Act of 1934) becomes the “beneficial owner” (as defined in Rule 13d-3
under the Securities Exchange Act of 1934), directly or indirectly, of a sufficient number of shares of all classes of stock then outstanding of Borrower ordinarily entitled to vote in the election of directors, empowering such “person” or
“group” to elect a majority of the Board of Directors of Borrower, who did not have such power before such transaction. 
 “Closing
Date” means the date of this Agreement. 
 “Code” means the North Carolina Uniform Commercial Code as amended or supplemented from time to
time. 

  
 1 

 “Collateral” means the property described on Exhibit B attached hereto and all Negotiable Collateral to
the extent not described on Exhibit B, except to the extent any such property (i) is nonasstgnable by its terms without the consent of the licensor thereof or another party (but only to She extent such prohibition on transfer is enforceable
under applicable law, including, without limitation, §25-9-406 and §25-9-408 of the Code), (ii) the granting of a security interest therein is contrary to applicable law, provided that upon the cessation of any such restriction or
prohibition, such property shall automatically become part of the Collateral, (iii) constitutes the capital stock of a controlled foreign corporation (as defined in the IRC), in excess of 65% of the voting power of all classes of capital stock
of such controlled foreign corporations entitled to vote, or (iv) property (including any attachments, accessions or replacements) that is subject to a Lien that is permitted pursuant to clause (c) of the definition of Permitted Liens, if the
grant of a security interest with respect to such property pursuant to this Agreement would be prohibited by the agreement creating such Permitted Lien or would otherwise constitute a default thereunder, provided, that such property will be deemed
“Collateral” hereunder upon the termination and release of such Permitted Lien. 
 “Collateral State” means the state or states where
the Collateral is located, which are California and Massachusetts. 
 “Compliance Certificate” means a compliance certificate, in substantially
the form of Exhibit D attached hereto, executed by a Responsible Officer of the Borrower. 
 “Contingent Obligation” means, as applied to any
Person, any direct or indirect liability, contingent or otherwise, of that Person with respect to (i) any indebtedness, lease, dividend, letter of credit or other obligation of another, including, without limitation, any such obligation
directly or indirectly guaranteed, endorsed, co-made or discounted or sold with recourse by that Person, or in respect of which that Person is otherwise directly or indirectly liable; (ii) any obligations with respect to undrawn letters of
credit, corporate credit cards or merchant services issued for the account of that Person; and (iii) all obligations arising under any interest rate, currency or commodity swap agreement, interest rate cap agreement, interest rate collar
agreement, or other agreement or arrangement designated to protect a Person against fluctuation in interest rates, currency exchange rates or commodity prices; provided, however, that the term “Contingent Obligation” shall not include
endorsements for collection or deposit in the ordinary course of business. The amount of any Contingent Obligation shall be deemed to be an amount equal to the stated or determined amount of the primary obligation in respect of which such Contingent
Obligation is made or, if not stated or determinable, the maximum reasonably anticipated liability in respect thereof as determined by such Person in good faith; provided, however, that such amount shall not in any event exceed the maximum amount of
the obligations under the guarantee or other support arrangement. 
 “Copyrights” means any and all copyright rights, copyright applications,
copyright registrations and like protections in each work or authorship and derivative work thereof, whether published or unpublished and whether or not the same also constitutes a trade secret, now or hereafter existing, created, acquired or held.

 “Credit Extension” means each Term Loan, or any other extension of credit by Bank, to or for the benefit of Borrower hereunder. 

“Equipment” means all present and future machinery, equipment, tenant improvements, furniture, fixtures, vehicles, tools, parts and attachments in
which Borrower has any interest. 
 “ERISA” means the Employee Retirement Income Security Act of 1974, as amended, and the regulations thereunder.

 “Event of Default” has the meaning assigned in Article 8. 

“GAAP” means generally accepted accounting principles, consistently applied, as in effect from time to time in the United States. 

“Indebtedness” means (a) all indebtedness for borrowed money or the deferred purchase price of property or services, including without
limitation reimbursement and other obligations with respect to surety bonds and letters of credit, (b) all obligations evidenced by notes, bonds, debentures or similar instruments, (c) all capital lease obligations, and (d) all
Contingent Obligations, including but not limited to any sublimit contained herein. 

  
 2 

 “Insolvency Proceeding” means any proceeding commenced by or against any Person or entity under any
provision of the United States Bankruptcy Code, as amended, or under any other bankruptcy or insolvency law, including assignments for the benefit of creditors, formal or informal moratoria, compositions, extension generally with its creditors, or
proceedings seeking reorganization, arrangement, or other relief. 
 “Intellectual Property” means all of Borrower’s right, title, and
interest in and to the following: 
 (a) Copyrights, Trademarks and Patents; 

(b) Any and all trade secrets, and any and all intellectual property rights in computer software and computer software products now or
hereafter existing, created, acquired or held; 
 (c) Any and all design rights which may be available to Borrower now or hereafter
existing, created, acquired or held; 
 (d) Any and all claims for damages by way of past, present and future infringement of any of
the rights included above, with the right, but not the obligation, to sue for and collect such damages for said use or infringement of the intellectual property rights identified above; 

(e) All licenses or other rights to use any Copyrights, Patents or Trademarks, and all license fees and royalties arising from such use
to the extent permitted by such license or rights; 
 (f) All amendments, renewals and extensions of any of the Copyrights, Trademarks
or Patents; and 
 (g) All proceeds and products of the foregoing, including without limitation all payments under insurance or any
indemnity or warranty payable in respect of any of the foregoing. 
 “Inventory” means all present and future inventory in which Borrower has any
interest. 
 “Investment” means any beneficial ownership of (including stock, partnership or limited liability company interest or other
securities) any Person, or any loan, advance or capital contribution to any Person. 
 “Investment Agreement” means, collectively, Borrower’s
stock purchase and other agreement(s) pursuant to which Borrower most recently issued its preferred stock. 
 “IPO” means an initial public
offering of Borrower’s equity securities on a nationally recognized exchange. 
 “IRC” means the Internal Revenue Code of 1986, as amended,
and the regulations thereunder. 
 “Lien” means any mortgage, lien, deed of trust, charge, pledge, security interest or other encumbrance. 

“Loan Documents” means, collectively, this Agreement, any note or notes executed by Borrower, and any other document, instrument or agreement
entered into in connection with this Agreement, all as amended or extended from time to time. 
 “Material Adverse Effect” means a material
adverse effect on (i) the operations, business or financial condition of Borrower and its Subsidiaries taken as a whole, (ii) the ability of Borrower to repay the Obligations or otherwise perform its obligations under the Loan Documents,
or (iii) Borrower’s interest in, or the value, perfection or priority of Bank’s security interest in the Collateral. 
 “MSC Investment
Conditions” means that Borrower has on deposit with Bank or Bank’s affiliates (subject to an account control agreement) Cash in an aggregate amount greater than or equal to 1.5x (one and a half times) all Obligations owing from Borrower to
Bank. 

  
 3 

 “MSC Subsidiary” has the meaning assigned in Section 7.7. 

“Negotiable Collateral” means all of Borrower’s present and future letters of credit of which it is a beneficiary, drafts, instruments
(including promissory notes), securities, documents of title, and chattel paper, and Borrower’s Books relating to any of the foregoing. 

“Obligations” means all debt, principal, interest, Bank Expenses and other amounts owed to Bank by Borrower pursuant to this Agreement or any other
agreement, whether absolute or contingent, due or to become due, now existing or hereafter arising, including any interest that accrues after the commencement of an Insolvency Proceeding and including any debt, liability, or obligation owing from
Borrower to others that Bank may have obtained by assignment or otherwise, but excluding any obligations of Borrower to Bank under or relating to any warrant or other right to purchase stock of Borrower. 

“Patents” means all patents, patent applications and like protections including without limitation improvements, divisions, continuations, renewals,
reissues, extensions and continuations-in-part of the same. 
 “Periodic Payments” means all installments or similar recurring payments that
Borrower may now or hereafter become obligated to pay to Bank pursuant to the terms and provisions of any instrument, or agreement now or hereafter in existence between Borrower and Bank. 

“Permitted Indebtedness” means: 

(a) Indebtedness of Borrower in favor of Bank arising under this Agreement or any other Loan Document; 

(b) Indebtedness existing on the Closing Date and disclosed in the Schedule; 

(c) Indebtedness not to exceed $250,000 in the aggregate at any time secured by a lien described in clause (c) of the defined term
“Permitted Liens,” provided such Indebtedness does not exceed at the time it is incurred the lesser of the cost or fair market value of the property financed with such Indebtedness; 

(d) Subordinated Debt; 

(e) the Silicon Valley Bank Letter of Credit; 

(f) Indebtedness to trade creditors incurred in the ordinary course of business; 

(g) Unsecured Indebtedness consisting of interest rate, currency or commodity swap agreements, interest rate, cap or collar agreements
or arrangements entered into in the ordinary course of business and designed to protect Borrower or its Subsidiaries against fluctuations in interest rates, currency exchange rates or commodity prices in an amount not to exceed $150,000 at any time;

 (h) Indebtedness that otherwise constitutes a Permitted Investment; 

(i) Indebtedness incurred as a result of endorsing negotiable instruments received in the ordinary course of business; 

(j) To the extent constituting Indebtedness obligations, Indebtedness incurred in connection with the financing of insurance premiums in
the ordinary course of business; 
 (k) (i) Indebtedness owing from any Subsidiary that is a guarantor to Borrower or any Subsidiary
that is a guarantor, (ii) Indebtedness owing from a Subsidiary that is not a guarantor to any other Subsidiary that is not a guarantor, and (iii) Indebtedness owing from any Subsidiary that is not guarantor to Borrower or any Subsidiary
that is a guarantor not to exceed $100,000 at any time outstanding; 

  
 4 

 (l) Other unsecured Indebtedness in an aggregate amount outstanding not to exceed
$250,000; and 
 (m) Extensions, refinancings and renewals of any items of Permitted Indebtedness, provided that the principal amount
is not increased or the terms modified to impose more burdensome terms upon Borrower or its Subsidiary, as the case may be. 
 “Permitted
Investment” means: 
 (a) Investments existing on the Closing Date disclosed in the Schedule; 

(b) (i) Marketable direct obligations issued or unconditionally guaranteed by the United States of America or any agency or any State
thereof maturing within one year from the date of acquisition thereof, (ii) commercial paper maturing no more than one year from the date of creation thereof and currently having rating of at least A-2 or P-2 from either Standard &
Poor’s Corporation or Moody’s Investors Service, (iii) Bank’s certificates of deposit maturing no more than one year from the date of investment therein, and (iv) Bank’s money market accounts or other money market funds
at least ninety-five percent (95%) of the assets of which constitute investments of the type listed in clauses (i) through (iii); (v) Investments in regular deposit or checking accounts held with Bank or as otherwise permitted by, and
subject to the terms and conditions of, Section 6.6 of this Agreement; and (vi) Investments consistent with any investment policy adopted by the Borrower’s board of directors; 

(c) Investments accepted in connection with Permitted Transfers; 

(d) Investments (i) of Subsidiaries in or to other Subsidiaries or Borrower, (ii) Investments by Borrower in another Borrower
or a Subsidiary that is a guarantor hereunder, (iii) by Borrower in Subsidiaries that are not Borrowers or guarantors not to exceed $250,000 in the aggregate in any fiscal year of Borrower and (iv) in any MSC Subsidiary otherwise permitted
in accordance with the terms of this Agreement; 
 (e) Investments not to exceed $250,000 outstanding in the aggregate at any time
consisting of (i) travel advances and employee relocation loans and other employee loans and advances in the ordinary course of business, and (ii) loans to employees, officers or directors relating to the purchase of equity securities of
Borrower or its Subsidiaries pursuant to employee stock purchase plan agreements approved by Borrower’s Board of Directors; 

(f) Investments(including debt obligations) received in connection with the bankruptcy or reorganization of customers or suppliers and
in settlement of delinquent obligations of, and other disputes with, customers or suppliers arising in the ordinary course of Borrower’s business; 

(g) Investments consisting of notes receivable of, or prepaid royalties and other credit extensions, to customers and suppliers who are
not Affiliates, in the ordinary course of business, provided that this subparagraph (g) shall not apply to Investments of Borrower in any Subsidiary; 

(h) Joint ventures or strategic alliances in the ordinary course of Borrower’s business consisting of the non-exclusive licensing
of technology, the development of technology or the providing of technical support, provided that any cash Investments by Borrower do not exceed $250,000 in the aggregate in any fiscal year; 

(i) Investments permitted under Section 7.3; and 

(j) Investments not otherwise permitted hereunder in aggregate amount not to exceed $250,000 per fiscal year. 

  
 5 

 “Permitted Licenses” means licenses granted in the ordinary course of Borrower’s business that are
either (i) nonexclusive or (ii) exclusive with respect to certain, but not all, rights and uses. 
 “Permitted Liens” means the
following: 
 (a) Any Liens existing on the Closing Date and disclosed in the Schedule (excluding Liens to be satisfied with the
proceeds of the Credit Extensions) or arising under this Agreement, the other Loan Documents, or any other agreement in favor of Bank; 

(b) Liens for taxes, fees, assessments or other governmental charges or levies, either not delinquent or being contested in good faith
by appropriate proceedings and for which Borrower maintains adequate reserves; 
 (c) Liens not to exceed $250,000 in the aggregate at
any time (i) upon or in any Equipment (other than Equipment financed by a Credit Extension) acquired or held by Borrower or any of its Subsidiaries to secure the purchase price of such Equipment or indebtedness incurred solely for the purpose
of financing the acquisition or lease of such Equipment, or (ii) existing on such Equipment at the time of its acquisition, in each case provided that the Lien is confined solely to the property so acquired and improvements thereon, and the
proceeds of such Equipment; 
 (d) Liens incurred in connection with the extension, renewal or refinancing of the indebtedness secured
by Liens of the type described in clauses (a) through (c) above, provided that any extension, renewal or replacement Lien shall be limited to the property encumbered by the existing Lien and the principal amount of the indebtedness being
extended, renewed or refinanced does not increase; 
 (e) Liens on the Silicon Valley Bank Cash Collateral Account securing
Borrower’s obligations with respect to the Silicon Valley Bank letter of Credit; 
 (f) Liens securing Subordinated Debt; 

(g) Liens arising from judgments, decrees or attachments in circumstances not constituting an Event of Default under Sections 8.4
(attachment) or 8.7 (judgments). 
 (h) Liens of carriers, warehousemen, suppliers or other Persons that are possessory in nature
arising in the ordinary course of business; 
 (i) Liens to secure the payment of worker’s compensation, employment insurance,
old age pensions, social security, bonds to secure 401k or similar retirement plans and other like obligations incurred in the ordinary course of business (other than Liens imposed by ERISA); 

(j) Permitted Licenses; 

(k) Deposits securing the performance of bids, trade contracts for the purchase of property, leases, statutory obligations, surety and
appeal bonds, performance bonds and other obligations of a like nature, in each case incurred in the ordinary course of business not representing an obligation for borrowed money; and 

(1) Subject to Section 6.6, Liens in favor of other financial institutions arising in connection with Borrower’s deposit
and/or securities accounts held at such institutions; provided that Bank has a perfected security interest in the amounts held in such deposit and securities accounts. 

“Permitted Transfer” means the conveyance, sale, lease, transfer or disposition by Borrower or any Subsidiary of: 

(a) Inventory in the ordinary course of business; 

(b) Permitted Licenses; 

  
 6 

 (c) worn-out, surplus or obsolete Equipment; 

(d) grants of security interests and other Liens that constitute Permitted Liens; 

(e) Permitted Investments; 

(f) the sale or issuance of any stock of Borrower permitted under this Agreement; 

(g) the use or transfer of cash or cash equivalents in the ordinary course of business and in a manner not otherwise prohibited by this
Agreement; and 
 (h) other assets of Borrower or its Subsidiaries that do not in the aggregate exceed $500,000 during any fiscal
year. 
 “Person” means any individual, sole proprietorship, partnership, limited liability company, joint venture, trust, unincorporated
organization, association, corporation, institution, public benefit corporation, firm, joint stock company, estate, entity or governmental agency. 

“Prime Rate” means the variable rate of interest, per annum, most recently announced by Bank, as its “prime rate,” whether or not such
announced rate is the lowest rate available from Bank. 
 “Responsible Officer” means each of the Chief Executive Officer, the Chief Operating
Officer, the Chief Financial Officer, Vice President of Finance and the Controller of Borrower, as well as any other officer or employee identified as an Authorized Officer in the corporate resolution delivered by Borrower to Bank in connection with
this Agreement. 
 “Schedule” means the schedule of exceptions attached hereto and approved by Bank, if any. 

“Silicon Valley Bank Cash Collateral Account” means account number XXXXXX0534 held at Silicon Valley Bank securing Borrower’s obligations under
the Silicon Valley Bank Letter of Credit. 
 “Silicon Valley Bank Letter of Credit” means letter of credit number SVBSF010173 issued by Silicon
Valley Bank, naming Borrower as beneficiary in the face amount of $1,255,400. 
 “SOS Reports” means the official reports from the Secretaries of
State of each Collateral State, the state where Borrower’s chief executive office is located, the state of Borrower’s formation and other applicable federal, state or local government offices identifying all current security interests
filed in the Collateral and Liens of record as of the date of such report. 
 “Subordinated Debt” means any debt incurred by Borrower that is
subordinated in writing to the debt owing by Borrower to Bank on terms reasonably acceptable to Bank (and identified as being such by Borrower and Bank). 

“Subsidiary” means any corporation, partnership or limited liability company or joint venture in which (i) any general partnership interest or
(ii) more than 50% of the stock, limited liability company interest or joint venture of which by the terms thereof ordinary voting power to elect the Board of Directors, managers or trustees of the entity, at the time as of which any
determination is being made, is owned by Borrower, either directly or through an Affiliate. 
 “Term Loan Maturity Date” means January 19,
2021. 
 “Trademarks” means any trademark and servicemark rights, whether registered or not, applications to register and registrations of the
same and like protections, and the entire goodwill of the business of Borrower connected with and symbolized by such trademarks. 
 “Warrant”
means (i) that certain Warrant to purchase stock issued by Borrower to Bank on the Closing Date and (ii) any additional Warrants issued by Borrower to Bank at any time after the Closing Date and in connection with this Agreement. 

  
 7 

			
	DEBTOR	  	UNUM THERAPEUTICS, INC.
		
	SECURED PARTY:                    	  	PACIFIC WESTERN BANK

 EXHIBIT B 

COLLATERAL DESCRIPTION ATTACHMENT TO LOAN AND SECURITY AGREEMENT 

All of Borrower’s (herein referred to as “Borrower” or “Debtor”) right, title and interest in its personal property whether presently
existing or hereafter created or acquired, and wherever located, including, but not limited to: 
 (a) all accounts (including
health-care-insurance receivables), chattel paper (including tangible and electronic chattel paper), deposit accounts, documents (including negotiable documents), equipment (including all accessions and additions thereto), financial assets, general
intangibles (including patents, trademarks, copyrights, goodwill, payment intangibles, domain names and software), goods (including fixtures), instruments (including promissory notes), inventory (including all goods held for sale or lease or to be
furnished under a contract of service, and including returns and repossessions), investment property (including securities and securities entitlements), letter of credit rights, money, and all of Debtor’s books and records with respect to any
of the foregoing, and the computers and equipment containing said books and records; 
 (b) any and all cash proceeds and/or noncash
proceeds of any of the foregoing, including, without limitation, insurance proceeds, and all supporting obligations and the security therefor or for any right to payment. All terms above have the meanings given to them in the North Carolina Uniform
Commercial Code, as amended or supplemented from time to time, including revised Division 9 of the Uniform Commercial Code Secured Transactions. 

Notwithstanding the foregoing, the Collateral shall not include any of the intellectual Property (as defined in that certain Loan and Security
Agreement by and between Borrower and Pacific Western Bank dated as of January 19, 2017); provided, however, that the Collateral shall include all accounts and general intangibles that consist of rights to payment and proceeds from the sale,
licensing or disposition of all or any part, or rights in, the foregoing (the “Rights to Payment”). 
 Notwithstanding the
foregoing, if a judicial authority (including a U.S. Bankruptcy Court) holds that a security interest in the underlying Intellectual Property is necessary to have a security interest in the Rights to Payment, then the Collateral shall automatically,
and effective as of January 19, 2017, include the Intellectual Property to the extent and only to the extent necessary to permit perfection of Bank’s security interest in the Rights to Payment, and further provided, however, that
Bank’s enforcement rights with respect to any security interest in the Intellectual Property shall be absolutely limited to the Rights to Payment only, and Bank shall have no recourse whatsoever with respect to the underlying Intellectual
Property. 

 EXHIBIT C 

LOAN ADVANCE / PAYDOWN REQUEST FORM 

[Please refer to New Borrower Kit] 

  

 EXHIBIT D 

COMPLIANCE CERTIFICATE 

[Please refer to New Borrower Kit] 

 EXHIBIT E-1 

FORM OF WARRANT TO PURCHASE PREFERRED STOCK 

[see attached] 

 THIS WARRANT AND THE SHARES ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH APPLICABLE LAW. THE WARRANT AND THE SHARES ISSUABLE HEREUNDER ARE SUBJECT TO THE RESTRICTIONS ON TRANSFER SET FORTH IN SECTION 5 OF THIS WARRANT. 

WARRANT TO PURCHASE STOCK 
  

			
	Corporation:	  	UNUM THERAPEUTICS, INC.
	Number of Shares:	  	[1.00% of applicable Term Loan/Initial Exercise Price]
	Class of Stock:	  	Series      Preferred [last round series]
	Initial Exercise Price:	  	$             per share [last round price]
	Issue Date:	  	
	Expiration Date:	  	[ten years after Issue Date]

 THIS WARRANT CERTIFIES THAT, for good and
valuable consideration, the receipt of which is hereby acknowledged, PACIFIC WESTERN BANK or its assignee or transferee (“Holder”) is entitled to purchase the
number of fully paid and nonassessable shares of the class of securities (the “Shares”) of the corporation (the “Company”) at the initial exercise price per Share (the “Warrant
Price”) all as set forth above and as adjusted pursuant to Article 2 of this warrant, subject to the provisions and upon the terms and conditions set forth in this warrant. Reference is made to Section 4.4 of this warrant, whereby
Pacific Western Bank shall transfer this warrant to its parent company, PacWest Bancorp. 
 ARTICLE 1 

EXERCISE 

1.1    Method of Exercise. Holder may exercise this warrant by delivering this warrant and a duly executed
Notice of Exercise in substantially the form attached as Appendix 1 to the principal office of the Company. Unless Holder is exercising the conversion right set forth in Section 1.2, Holder shall also deliver to the Company a check for the
aggregate Warrant Price for the Shares being purchased. 
 1.2    Conversion Right. In lieu of exercising
this warrant as specified in Section 1.1, Holder may from time to time convert this warrant, in whole or in part, into a number of Shares determined by dividing (a) the aggregate fair market value of the Shares or other securities
otherwise issuable upon exercise of this warrant minus the aggregate Warrant Price of such Shares by (b) the fair market value of one Share. The fair market value of the Shares shall be determined pursuant to Section 1.3. 

1.3    Fair Market Value. If the Shares are traded regularly in a public market, the fair market value of
the Shares shall be the closing price of the Shares (or the closing price of the Company’s stock into which the Shares are convertible) reported for the business day immediately before Holder delivers its Notice of Exercise to the Company. If
the Shares are not regularly traded in a public market, the Board of Directors of the Company shall determine fair market value in its reasonable good faith judgment. 

 1.4    Delivery of Certificate and New Warrant. Promptly after
Holder exercises or converts this warrant, the Company shall deliver to Holder certificates for the Shares acquired and, if this warrant has not been fully exercised or converted and has not expired, a new warrant representing the Shares not so
acquired. 
 1.5    Replacement of Warrants. On receipt of evidence reasonably satisfactory to the Company
of the loss, theft, destruction or mutilation of this warrant and, in the case of loss, theft or destruction, on delivery of an indemnity agreement reasonably satisfactory in form and amount to the Company or, in the case of mutilation, on surrender
and cancellation of this warrant, the Company at its expense shall execute and deliver, in lieu of this warrant, a new warrant of like tenor. 

1.6    Treatment of Warrant Upon Acquisition of the Company. 

1.6.1    “Acquisition.” For the purpose of this warrant, “Acquisition”
means (a) a merger or consolidation in which the Company is a constituent party or a subsidiary of the Company is a constituent party and the Company issues shares of its capital stock pursuant to such merger or consolidation (except any such
merger or consolidation involving the Company or a subsidiary in which the shares of capital stock of the Company outstanding immediately prior to such merger or consolidation continue to represent, or are converted into or exchanged for shares of
capital stock that represent, immediately following such merger or consolidation, at least a majority, by voting power, of the capital stock of (1) the surviving or resulting Company; or (2) if the surviving or resulting corporation is a
wholly owned subsidiary of another corporation immediately following such merger or consolidation, the parent corporation of such surviving or resulting corporation; or (b) the sale, lease, transfer, exclusive license or other disposition, in a
single transaction or series of related transactions, by the Company or any subsidiary of the Company of all or substantially all the assets of the Company and its subsidiaries taken as a whole or the sale or disposition (whether by merger,
consolidation or otherwise) of one or more subsidiaries of the Company if substantially all of the assets of the Company and its subsidiaries taken as a whole are held by such subsidiary or subsidiaries, except where such sale, lease, transfer,
exclusive license or other disposition is to a wholly owned subsidiary of the Company. 
 1.6.2    Exercise
Upon Acquisition. Upon the closing of any Acquisition in which the consideration to be received by the Company’s stockholders consists of cash, marketable securities, or a combination of both cash and marketable securities, this warrant
shall be deemed to have been automatically converted pursuant to Section 1.2, and thereafter Holder shall participate in the Acquisition on the same terms as other holders of the same class of securities of the Company. 

1.6.3    Assumption of Warrant. Upon the closing of any Acquisition not referred to in Section 1.6.2,
the Company shall cause the successor entity to assume the obligations of this warrant, and this warrant shall thereafter be exercisable for the same securities and/or other property as would have been paid for the Shares issuable upon exercise of
the 

  
 2. 

 
unexercised portion of this warrant as if such Shares were outstanding on and as of the closing of such Acquisition, subject to further adjustment from time to time in accordance with the
provisions of this warrant. 
 ARTICLE 2 

ADJUSTMENTS TO THE SHARES 

2.1    Stock Dividends, Splits, Etc. If the Company declares or pays a dividend on its common stock payable
in common stock, or other securities, or subdivides the outstanding common stock into a greater amount of common stock, then upon exercise of this warrant, for each Share acquired, Holder shall receive, without cost to Holder, the total number and
kind of securities to which Holder would have been entitled had Holder owned the Shares of record as of the date the dividend or subdivision occurred. 

2.2    Reclassification, Exchange or Substitution. Upon any reclassification, exchange, substitution, or
other event that results in a change of the number and/or class of the securities issuable upon exercise or conversion of this warrant, Holder shall be entitled to receive, upon exercise or conversion of this warrant, the number and kind of
securities and property that Holder would have received for the Shares if this warrant had been exercised immediately before such reclassification, exchange, substitution, or other event. Such an event shall include any automatic conversion of the
outstanding or issuable securities of the Company of the same class or series as the Shares to common stock pursuant to the terms of the Company’s Articles of Incorporation upon the closing of a registered public offering of the Company’s
common stock. The Company or its successor shall promptly issue to Holder a new warrant for such new securities or other property. The new warrant shall provide for adjustments which shall be as nearly equivalent as may be practicable to the
adjustments provided for in this Article 2 including, without limitation, adjustments to the Warrant Price and to the number of securities or property issuable upon exercise of the new warrant. The provisions of this Section 2.2 shall similarly
apply to successive reclassifications, exchanges, substitutions, or other events. 
 2.3    Adjustments for
Combinations, Etc. If the outstanding Shares are combined or consolidated, by reclassification or otherwise, into a lesser number of shares, the Warrant Price shall be proportionately increased. If the outstanding Shares are combined or
consolidated, by reclassification or otherwise, into a greater number of shares, the Warrant Price shall be proportionately decreased. 

2.4    Adjustments for Diluting Issuances. In the event of the issuance (a “Diluting
Issuance”) by the Company after the Issue Date of securities at a price per share less than the Warrant Price, then the number of shares of common stock issuable upon conversion of the Shares shall be adjusted in accordance with those
provisions of the Company’s Articles (Certificate) of Incorporation that apply to Diluting Issuances. If the antidilution rights are waived pursuant to the terms of the Company’s Certificate of Incorporation with respect to a particular
Diluting Issuance then there shall be no adjustment to the number of shares of common stock issuable upon conversion of the Shares with respect to that Diluting Issuance. 

  
 3. 

 2.5    Certificate as to Adjustments. Upon each adjustment of
the Warrant Price, the Company at its expense shall promptly compute such adjustment, and furnish Holder with a certificate of its Chief Financial Officer setting forth such adjustment and the facts upon which such adjustment is based. The Company
shall, upon written request, furnish Holder a certificate setting forth the Warrant Price in effect upon the date thereof and the series of adjustments leading to such Warrant Price. 

2.6    Fractional Shares. No fractional Shares shall be issuable upon exercise or conversion of the warrant
and the Number of Shares to be issued shall be rounded down to the nearest whole Share. If a fractional share interest arises upon any exercise or conversion of the warrant, the Company shall eliminate such fractional share interest by paying Holder
the amount computed by multiplying the fractional interest by the fair market value of a full Share. 
 ARTICLE 3 

REPRESENTATIONS AND COVENANTS OF THE COMPANY 

3.1    Representations and Warranties. The Company hereby represents and warrants to the Holder as follows:

 (a)    The initial Warrant Price referenced on the first page of this warrant is not greater than the lowest
price at which the Company sold its Series [    ] Preferred Stock. 
 (b)    All Shares which
may be issued upon the exercise of the purchase right represented by this warrant, and all securities, if any, issuable upon conversion of the Shares, shall, upon issuance, be duly authorized, validly issued, fully paid and nonassessable, and free
of any liens and encumbrances except for restrictions on transfer provided for herein or under applicable federal and state securities laws. 

(c)    The Company’s capitalization table attached to this warrant is true and complete as of the Issue Date.

 3.2    Notice of Certain Events. The Company shall provide Holder with not less than 5 Business Days
prior written notice of, including a description of the material facts surrounding, any of the following events: (a) declaration of any dividend or distribution upon its common stock, whether in cash, property, stock, or other securities and
whether or not a regular cash dividend; (b) offering for subscription pro rata to the holders of any class or series of its stock any additional shares of stock of any class or series or other rights; (c) effecting any reclassification or
recapitalization of common stock; or (d) the merger or consolidation with or into any other corporation, or sale, lease, license, or conveyance of all or substantially all of its assets, or liquidation, dissolution or winding up. 

3.3    Information Rights. So long as the Holder holds this warrant and/or any of the Shares, the Company
shall deliver to the Holder, upon request by the Holder (a) promptly after mailing, copies of communiques sent to all the shareholders of the Company, (b) within one hundred eighty (180) days after the end of each fiscal year of the
Company, the annual audited financial statements of the Company certified by independent public accountants of recognized standing and (c) within forty-five (45) days after the end of each of the first three quarters of each fiscal year,
the Company’s quarterly, unaudited financial statements. 

  
 4. 

 3.4    Registration Under Securities Act of 1933, as amended.
The Company agrees that the Shares or, if the Shares are convertible into common stock of the Company, such common stock, shall be “Registrable Securities”, and Holder shall be a “Holder” under the Investor Rights Agreement among
the Company and other persons dated as of June 10, 2015. 
 3.5    Holder Investment Representations.
Holder makes the representations to the Company set forth in Exhibit A hereof in connection with the issuance of this warrant and the Shares (collectively, the “Securities”). 

ARTICLE 4 
 MISCELLANEOUS

 4.1    Term: Exercise Upon Expiration. This warrant is exercisable in whole or in part, at any time and
from time to time on or before the Expiration Date set forth above. If this warrant has not been exercised prior to the Expiration Date, this warrant shall be deemed to have been automatically exercised on the Expiration Date by “cashless”
conversion pursuant to Section 1.2. 
 4.2    Legends. This warrant and the Shares (and the
securities issuable, directly or indirectly, upon conversion of the Shares, if any) shall be imprinted with a legend in substantially the following form: 

THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE
WITH APPLICABLE LAW. 
 4.3    Compliance with Securities Laws on Transfer. This warrant and the Shares
issuable upon exercise of this warrant (and the securities issuable, directly or indirectly, upon conversion of the Shares, if any) may not be transferred or assigned in whole or in part without compliance with applicable federal and state
securities laws by the transferor and the transferee. The Company shall not require Holder to provide an opinion of counsel if the transfer is to PacWest Bancorp or any other affiliate of Holder or if there is no material question as to the
availability of current information as referenced in Rule 144(c), Holder represents that it has complied with Rule 144 (d) and (e) in reasonable detail, the selling broker represents that it has complied with Rule 144(f), and the Company is
provided with a copy of Holder’s notice of proposed sale. 
 4.4    Transfer Procedure. Subject to
the provisions of Section 4.3, Holder may transfer all or part of this warrant or the Shares issuable upon exercise of this warrant (or the securities issuable, directly or indirectly, upon conversion of the Shares, if any) by giving the
Company notice of the portion of the warrant being transferred setting forth the name, address and taxpayer identification number of the transferee and surrendering this warrant to the Company for reissuance to the transferee(s) (and Holder, if
applicable). Notwithstanding the foregoing, after receipt by Pacific Western Bank of this warrant, Pacific Western Bank will 

  
 5. 

 
transfer all of this warrant to its parent company, PacWest Bancorp and no consent, surrender or reissuance shall be required for the transfer to PacWest Bancorp or a transfer to any other
affiliate of Holder. Notwithstanding the foregoing, without the prior written consent of the Company, Holder shall not transfer all or part of this warrant or the Shares issuable upon exercise of this warrant (or the securities issuable, directly or
indirectly, upon conversion of the Shares, if any) to any company that is a direct competitor of Borrower. 

4.5    Notices. All notices and other communications from the Company to the Holder, or vice versa, shall be
deemed delivered and effective when given personally or mailed by first-class registered or certified mail, postage prepaid, at such address as may have been furnished to the Company or the Holder, as the case may be, in writing by the Company or
such Holder from time to time. All notices to the Holder shall be addressed as follows: 
 PacWest Bancorp 

Attn: Warrant Administrator 
 406
Blackwell Street, Suite 240 
 Durham, NC 27701 

4.6    Amendments. This warrant and any term hereof may be changed, waived, discharged or terminated only by
an instrument in writing signed by the party against which enforcement of such change, waiver, discharge or termination is sought. 

4.7    Attorneys’ Fees. In the event of any dispute between the parties concerning the terms and
provisions of this warrant, the party prevailing in such dispute shall be entitled to collect from the other party all costs incurred in such dispute, including reasonable attorneys’ fees. 

4.8    Governing Law. This warrant shall be governed by and construed in accordance with the laws of the
State of Delaware without giving effect to its principles regarding conflicts of law. 
 [Signature Page Follows] 

  
 6. 

 IN WITNESS WHEREOF, the undersigned has executed this Warrant to Purchase Stock as of the date set forth above.

  

			
	UNUM THERAPEUTICS, INC.

 
			
		
	By:	 	  

		
	Name:	 	  

		
	Title:	 	  

 [Signature Page to Warrant to Purchase Stock] 

 APPENDIX 1 

NOTICE OF EXERCISE 

1.    The undersigned hereby elects to purchase
             shares of the              stock of UNUM THERAPEUTICS, INC. pursuant to the terms of the attached warrant,
and tenders herewith payment of the purchase price of such shares in full. 
 1.    The undersigned hereby elects
to convert the attached warrant into shares in the manner specified in the warrant. This conversion is exercised with respect to              of the shares covered by the warrant. 

[Strike paragraph that does not apply.] 

2.    Please issue a certificate or certificates representing said shares in the name of the undersigned or in such
other name as is specified below: 
  

	
	  

	(Holder’s Name)
	
	  

	
	  

	(Address)

 3.    The undersigned represents it is acquiring the shares solely for its own
account and not as a nominee for any other party and not with a view toward the resale or distribution thereof except in compliance with applicable securities laws. 

PACWEST BANCORP or Registered Assignee 

 

	
	  

	(Signature)
	
	  

	(Date)

 EXHIBIT A 

INVESTMENT REPRESENTATIONS 

(a)    The undersigned is aware of the Company’s business affairs and financial condition, and has acquired sufficient information
about the Company to reach an informed and knowledgeable decision to acquire the Securities. The undersigned is purchasing the Securities for its own account for investment purposes only, not as a nominee or agent, and not with a view towards, or
for resale in connection with, any “distribution” thereof for purposes of the Securities Act of 1933, as amended (the “Securities Act”). The undersigned has such knowledge and experience in financial business matters and the
undersigned is capable of evaluating the merits and risks of the purchase of the Securities and of protecting its interests in connection therewith. 

(b)    The undersigned understands that the Securities have not been registered under the Securities Act in reliance upon a specific
exemption therefrom, which exemption depends upon, among other things, the bona fide nature of the undersigned’s investment intent as expressed herein. 

(c)    The undersigned further understands that the Securities must be held indefinitely, and the undersigned must therefore bear the
economic risk therewith, unless the Securities are subsequently registered under the Securities Act or unless an exemption from registration is otherwise available. In addition, the undersigned understands that the certificate evidencing the
Securities will be imprinted with a legend which prohibits the transfer of the Securities unless they are registered or such registration is not required. 

(d)    The undersigned is familiar with the provisions of Rule 144, promulgated pursuant to the Securities Act, which, in substance,
permits limited public resale of “restricted securities” acquired, directly or indirectly, from the issuer thereof, in a non-public offering subject to the satisfaction of certain conditions. 

(e)    The Securities may be resold in certain limited circumstances subject to the provisions of Rule 144, which requires, among other
things, the existence of a public market for the Securities, the availability of certain current public information about the Company, the resale occurring not less than one year after a party has purchased and paid for the security to be sold, the
sales being effected through a “broker’s transaction” or in transactions directly with a “market maker” and the number of securities being sold during any three-month period not exceeding specified limitations. 

(f)    The undersigned further understands that in the event that all of the applicable requirements of Rule 144 are not satisfied,
registration under the Securities Act, compliance with Regulation A, or some other registration exemption will be required. 

(g)    The undersigned is an “accredited investor” as defined in Rule 501(a) of Regulation D promulgated under the Securities
Act. 

  
 2. 

 EXHIBIT E-2 

FORM OF WARRANT TO PURCHASE COMMON STOCK  

[see attached] 

 THIS WARRANT AND THE SHARES ISSUABLE HEREUNDER HAVE NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE WITH APPLICABLE LAW. THE WARRANT AND THE SHARES ISSUABLE HEREUNDER ARE SUBJECT TO THE RESTRICTIONS ON TRANSFER SET FORTH IN SECTION 5 OF THIS WARRANT. 

WARRANT TO PURCHASE COMMON STOCK 
  

			
	 Corporation:
	  	 UNUM THERAPEUTICS, INC.

	 Number of Shares:
	  	 [1.00% of applicable Term Loan/Initial Exercise Price]

	 Class of Stock:
	  	 Common Stock

	 Initial Exercise Price:
	  	 See Section 1.7

	 Issue Date:
	  	
	Expiration Date:	  	[ten years after Issue Date]

 THIS WARRANT CERTIFIES THAT, for good and
valuable consideration, the receipt of which is hereby acknowledged, PACIFIC WESTERN BANK or its assignee or transferee (“Holder”) is entitled to purchase the
number of fully paid and nonassessable shares of the class of securities (the “Shares”) of the corporation (the “Company”) at the initial exercise price per Share (the “Warrant
Price”) all as set forth above and as adjusted pursuant to Article 2 of this warrant, subject to the provisions and upon the terms and conditions set forth in this warrant. Reference is made to Section 4.4 of this warrant, whereby
Pacific Western Bank shall transfer this warrant to its parent company, PacWest Bancorp. 
 ARTICLE 1 

EXERCISE 

1.1    Method of Exercise. Holder may exercise this warrant by delivering this warrant and a duly executed
Notice of Exercise in substantially the form attached as Appendix 1 to the principal office of the Company. Unless Holder is exercising the conversion right set forth in Section 1.2, Holder shall also deliver to the Company a check for the
aggregate Warrant Price for the Shares being purchased. 
 1.2    Conversion Right. In lieu of exercising
this warrant as specified in Section 1.1, Holder may from time to time convert this warrant, in whole or in part, into a number of Shares determined by dividing (a) the aggregate fair market value of the Shares or other securities
otherwise issuable upon exercise of this warrant minus the aggregate Warrant Price of such Shares by (b) the fair market value of one Share. The fair market value of the Shares shall be determined pursuant to Section 1.3. 

1.3    Fair Market Value. The fair market value of the Shares shall be the closing price of the Shares
reported for the business day immediately before Holder delivers its Notice of Exercise to the Company. 

 1.4    Delivery of Certificate and New Warrant. Promptly after
Holder exercises or converts this warrant, the Company shall deliver to Holder certificates for the Shares acquired and, if this warrant has not been fully exercised or converted and has not expired, a new warrant representing the Shares not so
acquired. 
 1.5    Replacement of Warrants. On receipt of evidence reasonably satisfactory to the Company
of the loss, theft, destruction or mutilation of this warrant and, in the case of loss, theft or destruction, on delivery of an indemnity agreement reasonably satisfactory in form and amount to the Company or, in the case of mutilation, on surrender
and cancellation of this warrant, the Company at its expense shall execute and deliver, in lieu of this warrant, a new warrant of like tenor. 

1.6    Treatment of Warrant Upon Acquisition of the Company. 

1.6.1    “Acquisition.” For the purpose of this warrant, “Acquisition”
means (a) a merger or consolidation in which the Company is a constituent party or a subsidiary of the Company is a constituent party and the Company issues shares of its capital stock pursuant to such merger or consolidation (except any such
merger or consolidation involving the Company or a subsidiary in which the shares of capital stock of the Company outstanding immediately prior to such merger or consolidation continue to represent, or are converted into or exchanged for shares of
capital stock that represent, immediately following such merger or consolidation, at least a majority, by voting power, of the capital stock of (1) the surviving or resulting Company; or (2) if the surviving or resulting corporation is a
wholly owned subsidiary of another corporation immediately following such merger or consolidation, the parent corporation of such surviving or resulting corporation; or (b) the sale, lease, transfer, exclusive license or other disposition, in a
single transaction or series of related transactions, by the Company or any subsidiary of the Company of all or substantially all the assets of the Company and its subsidiaries taken as a whole or the sale or disposition (whether by merger,
consolidation or otherwise) of one or more subsidiaries of the Company if substantially all of the assets of the Company, and its subsidiaries taken as a whole are held by such subsidiary or subsidiaries, except where such sale, lease, transfer,
exclusive license or other disposition is to a wholly owned subsidiary of the Company. 
 1.6.2    Exercise
Upon Acquisition. Upon the closing of any Acquisition in which the consideration to be received by the Company’s stockholders consists of cash, marketable securities, or a combination of both cash and marketable securities, this warrant
shall be deemed to have been automatically converted pursuant to Section 1.2, and thereafter Holder shall participate in the Acquisition on the same terms as other holders of the same class of securities of the Company. 

1.6.3    Assumption of Warrant. Upon the closing of any Acquisition not referred to in Section 1.6.2,
the Company shall cause the successor entity to assume the obligations of this warrant, and this warrant shall thereafter be exercisable for the same securities and/or other property as would have been paid for the Shares issuable upon exercise of
the unexercised portion of this warrant as if such Shares were outstanding on and as of the closing of such Acquisition, subject to further adjustment from time to time in accordance with the provisions of this warrant. 

1.7    Initial Exercise Price. The “Initial Exercise Price” shall be the average closing price per
share of the Company’s common stock during the 30 day period preceding the Issue Date as such price is listed on the NASDAQ Stock Exchange.  

  
 2. 

 ARTICLE 2 

ADJUSTMENTS TO THE SHARES 

2.1    Stock Dividends, Splits, Etc. If the Company declares or pays a dividend on its common stock payable
in common stock, or other securities, or subdivides the outstanding common stock into a greater amount of common stock, then upon exercise of this warrant, for each Share acquired, Holder shall receive, without cost to Holder, the total number and
kind of securities to which Holder would have been entitled had Holder owned the Shares of record as of the date the dividend or subdivision occurred. 

2.2    Reclassification, Exchange or Substitution. Upon any reclassification, exchange, substitution, or
other event that results in a change of the number and/or class of the securities issuable upon exercise or conversion of this warrant, Holder shall be entitled to receive, upon exercise or conversion of this warrant, the number and kind of
securities and property that Holder would have received for the Shares if this warrant had been exercised immediately before such reclassification, exchange, substitution, or other event. The Company or its successor shall promptly issue to Holder a
new warrant for such new securities or other property. The new warrant shall provide for adjustments which shall be as nearly equivalent as may be practicable to the adjustments provided for in this Article 2 including, without limitation,
adjustments to the Warrant Price and to the number of securities or property issuable upon exercise of the new warrant. The provisions of this Section 2.2 shall similarly apply to successive reclassifications, exchanges, substitutions, or other
events. 
 2.3    Adjustments for Combinations, Etc. If the outstanding Shares are combined or
consolidated, by reclassification or otherwise, into a lesser number of shares, the Warrant Price shall be proportionately increased. If the outstanding Shares are combined or consolidated, by reclassification or otherwise, into a greater number of
shares, the Warrant Price shall be proportionately decreased. 
 2.4    Intentionally Omitted. 

2.5    Certificate as to Adjustments. Upon each adjustment of the Warrant Price, the Company at its expense
shall promptly compute such adjustment, and furnish Holder with a certificate of its Chief Financial Officer setting forth such adjustment and the facts upon which such adjustment is based. The Company shall, upon written request, furnish Holder a
certificate setting forth the Warrant Price in effect upon the date thereof and the series of adjustments leading to such Warrant Price. 

2.6    Fractional Shares. No fractional Shares shall be issuable upon exercise or conversion of the warrant
and the Number of Shares to be issued shall be rounded down to the nearest whole Share. If a fractional share interest arises upon any exercise or conversion of the warrant, the Company shall eliminate such fractional share interest by paying Holder
the amount computed by multiplying the fractional interest by the fair market value of a full Share. 

  
 3. 

 ARTICLE 3 

REPRESENTATIONS AND COVENANTS OF THE COMPANY 

3.1    Representations and Warranties. The Company hereby represents and warrants to the Holder as follows:

 (a)    All Shares which may be issued upon the exercise of the purchase right represented by this warrant, and
all securities, if any, issuable upon conversion of the Shares, shall, upon issuance, be duly authorized, validly issued, fully paid and nonassessable, and free of any liens and encumbrances except for restrictions on transfer provided for herein or
under applicable federal and state securities laws. 
 (b)    The Company’s capitalization table attached to
this warrant is true and complete as of the Issue Date. 
 3.2    Notice of Certain Events. The Company
shall provide Holder with not less than 5 Business Days prior written notice of, including a description of the material facts surrounding, any of the following events: (a) declaration of any dividend or distribution upon its common stock,
whether in cash, property, stock, or other securities and whether or not a regular cash dividend; (b) offering for subscription pro rata to the holders of any class or series of its stock any additional shares of stock of any class or series or
other rights; (c) effecting any reclassification or recapitalization of common stock; or (d) the merger or consolidation with or into any other corporation, or sale, lease, license, or conveyance of all or substantially all of its assets,
or liquidation, dissolution or winding up. 
 3.3    Holder Investment Representations. Holder makes the
representations to the Company set forth in Exhibit A hereof in connection with the issuance of this warrant and the Shares (collectively, the “Securities”). 

ARTICLE 4 

MISCELLANEOUS 

4.1    Term: Exercise Upon Expiration. This warrant is exercisable in whole or in part, at any time and from
time to time on or before the Expiration Date set forth above. If this warrant has not been exercised prior to the Expiration Date, this warrant shall be deemed to have been automatically exercised on the Expiration Date by “cashless”
conversion pursuant to Section 1.2. 
 4.2    Legends. This warrant and the Shares (and the
securities issuable, directly or indirectly, upon conversion of the Shares, if any) shall be imprinted with a legend in substantially the following form: 

THIS SECURITY HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS AMENDED, AND MAY NOT BE SOLD, PLEDGED OR OTHERWISE TRANSFERRED EXCEPT IN ACCORDANCE
WITH APPLICABLE LAW. 

  
 4. 

 4.3    Compliance with Securities Laws on Transfer. This
warrant and the Shares issuable upon exercise of this warrant (and the securities issuable, directly or indirectly, upon conversion of the Shares, if any) may not be transferred or assigned in whole or in part without compliance with applicable
federal and state securities laws by the transferor and the transferee. The Company shall not require Holder to provide an opinion of counsel if the transfer is to PacWest Bancorp or any other affiliate of Holder or if there is no material question
as to the availability of current information as referenced in Rule 144(c), Holder represents that it has complied with Rule 144 (d) and (e) in reasonable detail, the selling broker represents that it has complied with Rule 144(f), and the
Company is provided with a copy of Holder’s notice of proposed sale. 
 4.4    Transfer Procedure.
Subject to the provisions of Section 4.3, Holder may transfer all or part of this warrant or the Shares issuable upon exercise of this warrant (or the securities issuable, directly or indirectly, upon conversion of the Shares, if any) by giving
the Company notice of the portion of the warrant being transferred setting forth the name, address and taxpayer identification number of the transferee and surrendering this warrant to the Company for reissuance to the transferee(s) (and Holder, if
applicable). Notwithstanding the foregoing, after receipt by Pacific Western Bank of this warrant, Pacific Western Bank will transfer all of this warrant to its parent company, PacWest Bancorp and no consent, surrender or reissuance shall be
required for the transfer to PacWest Bancorp or a transfer to any other affiliate of Holder. Notwithstanding the foregoing, without the prior written consent of the Company, Holder shall not transfer all or part of this warrant or the Shares
issuable upon exercise of this warrant (or the securities issuable, directly or indirectly, upon conversion of the Shares, if any) to any company that is a direct competitor of Borrower. 

4.5    Notices. All notices and other communications from the Company to the Holder, or vice versa, shall be
deemed delivered and effective when given personally or mailed by first-class registered or certified mail, postage prepaid, at such address as may have been furnished to the Company or the Holder, as the case may be, in writing by the Company or
such Holder from time to time. All notices to the Holder shall be addressed as follows: 
 PacWest Bancorp 

Attn: Warrant Administrator 
 406
Blackwell Street, Suite 240 
 Durham, NC 27701 

4.6    Amendments. This warrant and any term hereof may be changed, waived, discharged or terminated only by
an instrument in writing signed by the party against which enforcement of such change, waiver, discharge or termination is sought. 

4.7    Attorneys’ Fees. In the event of any dispute between the parties concerning the terms and
provisions of this warrant, the party prevailing in such dispute shall be entitled to collect from the other party all costs incurred in such dispute, including reasonable attorneys’ fees. 

  
 5. 

 4.8    Governing Law. This warrant shall be governed by and
construed in accordance with the laws of the State of Delaware, without giving effect to its principles regarding conflicts of law. 

[Signature Page Follows] 

  
 6. 

 IN WITNESS WHEREOF, the undersigned has executed this Warrant to Purchase Stock as of the date set forth above.

  

			
	UNUM THERAPEUTICS, INC.

 
			
		
	By:	 	  

		
	Name:	 	  

		
	Title:	 	  

 [Signature Page to Warrant to Purchase Stock] 

 APPENDIX 1 

NOTICE OF EXERCISE 

1.    The undersigned hereby elects to purchase
             shares of the              stock of UNUM THERAPEUTICS, INC. pursuant to the terms of the attached warrant,
and tenders herewith payment of the purchase price of such shares in full. 
 1.    The undersigned hereby elects
to convert the attached warrant into shares in the manner specified in the warrant. This conversion is exercised with respect to              of the shares covered by the warrant. 

[Strike paragraph that does not apply.] 

2.    Please issue a certificate or certificates representing said shares in the name of the undersigned or in such
other name as is specified below: 
  

	
	  

	(Holder’s Name)
	
	  

	
	  

	(Address)

 3.    The undersigned represents it is acquiring the shares solely for its own
account and not as a nominee for any other party and not with a view toward the resale or distribution thereof except in compliance with applicable securities laws. 
  

	
	PACWEST BANCORP or Registered Assignee
	
	  

	 (Signature)

	
	  

	 (Date)

 EXHIBIT A 

INVESTMENT REPRESENTATIONS 

(a)    The undersigned is aware of the Company’s business affairs and financial condition, and has acquired sufficient information
about the Company to reach an informed and knowledgeable decision to acquire the Securities. The undersigned is purchasing the Securities for its own account for investment purposes only, not as a nominee or agent, and not with a view towards, or
for resale in connection with, any “distribution” thereof for purposes of the Securities Act of 1933, as amended (the “Securities Act”). The undersigned has such knowledge and experience in financial business matters and the
undersigned is capable of evaluating the merits and risks of the purchase of the Securities and of protecting its interests in connection therewith. 

(b)    The undersigned understands that the Securities have not been registered under the Securities Act in reliance upon a specific
exemption therefrom, which exemption depends upon, among other things, the bona fide nature of the undersigned’s investment intent as expressed herein. 

(c)    The undersigned further understands that the Securities must be held indefinitely, and the undersigned must therefore bear the
economic risk therewith, unless the Securities are subsequently registered under the Securities Act or unless an exemption from registration is otherwise available. In addition, the undersigned understands that the certificate evidencing the
Securities will be imprinted with a legend which prohibits the transfer of the Securities unless they are registered or such registration is not required. 

(d)    The undersigned is familiar with the provisions of Rule 144, promulgated pursuant to the Securities Act, which, in substance,
permits limited public resale of “restricted securities” acquired, directly or indirectly, from the issuer thereof, in a non-public offering subject to the satisfaction of certain conditions. 

(e)    The Securities may be resold in certain limited circumstances subject to the provisions of Rule 144, which requires, among other
things, the existence of a public market for the Securities, the availability of certain current public information about the Company, the resale occurring not less than one year after a party has purchased and paid for the security to be sold, the
sales being effected through a “broker’s transaction” or in transactions directly with a “market maker” and the number of securities being sold during any three-month period not exceeding specified limitations. 

(f)    The undersigned further understands that in the event that all of the applicable requirements of Rule 144 are not satisfied,
registration under the Securities Act, compliance with Regulation A, or some other registration exemption will be required. 

(g)    The undersigned is an “accredited investor” as defined in Rule 501(a) of Regulation D promulgated under the Securities
Act. 

 SCHEDULE OF EXCEPTIONS 

Permitted Indebtedness (Exhibit A) – None. 

Permitted Investments (Exhibit A) – 
 Borrower owns
100% of the MSC Subsidiary. 
 Permitted Liens (Exhibit A) – None. 

Prior Names (Section 5.5) – None. 

Litigation (Section 5.6) – None. 
 Inbound
Licenses (Section 5.12) – 
 Amended and Restated Exclusive License Agreement, dated November 15, 2015, by and among Borrower, National
University of Singapore and St. Judes Children’s Research Hospital, Inc.

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