Document:

EX-10.2

 Certain identified information has been excluded from this exhibit because it is both not material and
is the type that the registrant treats as private or confidential. Information that was omitted has been noted in this document with a placeholder identified by the mark “[***]”. 

Exhibit 10.2 
 EXCLUSIVE
LICENSE AGREEMENT 
 TABLE OF CONTENTS 

PREAMBLE 
 ARTICLES: 

 

			
	 1
	  	DEFINITIONS
	 2
	  	GRANT OF LICENSE; COVENANT NOT TO SUE [***]
	 3
	  	SUBLICENSES
	 4
	  	DILIGENCE
	 5
	  	PAYMENTS
	 6
	  	RECORDS AND REPORTS
	 7
	  	FILING, PROSECUTION, AND MAINTENANCE OF LICENSED PATENT RIGHTS
	 8
	  	INFRINGEMENT OF LICENSED PATENT RIGHTS
	 9
	  	CONFIDENTIALITY
	 10
	  	REPRESENTATIONS, WARRANTIES, AND COVENANTS
	 11
	  	INDEMNIFICATIONS; INSURANCE
	 12
	  	DISCLAIMER OF WARRANTIES; LIMITATION OF DAMAGES
	 13
	  	COMPLIANCE WITH LAW
	 14
	  	PUBLICATION; PRESS RELEASES; NON-USE OF NAMES
	 15
	  	ASSIGNMENT
	 16
	  	TERMINATION
	 17
	  	NOTICES AND OTHER COMMUNICATIONS
	 18
	  	MISCELLANEOUS PROVISIONS
	 Exhibit A
	  	LICENSED KNOW-HOW
	 Exhibit B
	  	LICENSED MATERIALS
	 Exhibit C
	  	LICENSED PATENT RIGHTS
	 Exhibit D
	  	SUCCESS PAYMENT AMOUNTS; CHANGE OF CONTROL PAYMENT
	 Exhibit E
	  	LICENSEE PRESS RELEASE
	 Exhibit F
	  	FORM OF SUBSCRIPTION AGREEMENT

 EXCLUSIVE LICENSE AGREEMENT 

This Exclusive License Agreement (the “Agreement”) is effective on the date of the last signature below (“Effective
Date”), and is by and between Memorial Sloan Kettering Cancer Center (hereinafter referred to as “MSK”), a New York not-for-profit corporation with
principal offices at 1275 York Avenue, New York, NY 10065, and Caribou Biosciences, Inc., a Delaware corporation with offices at 2929 Seventh St., Suite 105, Berkeley, CA 94710 (“LICENSEE”). MSK and LICENSEE are sometimes referred
to singly as “Party” and collectively as “Parties.” 
 WITNESSETH 

WHEREAS, MSK owns or Controls (as defined herein) certain Licensed Rights (as defined herein) and desires to have the Licensed Rights utilized
in the public interest; 
 WHEREAS, LICENSEE desires to obtain a license to the Licensed Rights to commercially develop one or more Licensed
Products (as defined herein) in the Field (as defined herein); and 
 WHEREAS, MSK is willing to grant such a license to LICENSEE on the
terms and conditions set forth herein for LICENSEE to commercially develop for public availability one or more Licensed Products; 
 NOW,
THEREFORE, in consideration of the premises and the mutual covenants contained herein, the sufficiency of which is acknowledged, the Parties hereto agree as follows: 

ARTICLE 1 - DEFINITIONS 

For the purpose of this Agreement, the following words and phrases shall have the following meanings: 

1.1 “Affiliate” as used herein in either singular or plural means, with respect to either Party, any corporation, company, partnership, joint
venture, or other entity that, directly or indirectly, Controls (as defined in Section 1.6), is Controlled by, or is under common Control with the specified entity. With regard to MSK, “Affiliate” shall include, without
limitation, Sloan-Kettering Institute for Cancer Research and the Memorial Hospital for Cancer and Allied Diseases. 
 1.2 “Calendar
Quarter” means the three (3) month periods ending on March 31, June 30, September 30, and December 31 of each Calendar Year (wherein a Calendar Year is that period of time from January 1
through December 31). 
 1.3 “Change of Control” means (a) a transaction or series of related transactions involving a Party,
in which the shareholders of such Party immediately prior to such transaction or series of related transactions cease to Control such Party after such transaction; (b) a sale or transfer, in a single transaction or series of related
transactions, of all or substantially all of the assets or business of such Party to a Third Party; (c) a sale of a Controlling (as defined in Section 1.6) interest of such Party to a Third Party. 

1.4 “Commercially Reasonable Efforts” means [***] 

1.5 “Confidential Information” means all confidential information disclosed by one Party to the other Party relating to and in the
performance of this Agreement including, but not limited to, information about research, development, preclinical, and clinical studies, regulatory affairs, intellectual property, operations, marketing, business plans, financial statements,
biological materials, software, product specifications, data, know-how and the like, whether tangible or intangible, and including all copies, abstracts, summaries, analyses, and other derivatives thereof
furnished by one Party (the “Disclosing Party”) to the other Party (the “Receiving Party”) that (a) is disclosed in writing or other tangible form and marked “Confidential,” “Proprietary” or in some other
manner to indicate its confidential nature; (b) is initially disclosed in oral or other intangible form and subsequently confirmed in writing within [***] calendar days after its initial disclosure; or (c) the nature of the
information and the manner of disclosure are such that a reasonable person would understand it to be confidential. 

 1.6 “Control” means, for purposes of the definition of Affiliates in Section 1.1 and
the definition of Change of Control in Section 1.3, the direct or indirect ownership or control of at least [***] of the right to direct or cause the direction of the policies and management of such person or entity, whether by the
ownership of stock, by contract or otherwise. In any jurisdiction where [***] control is not permitted by applicable laws, the [***] threshold shall be deemed satisfied by the possession of substantially the maximum percentage allowable in such
jurisdiction. With respect to intellectual property, “Control” means ownership together with the ability to grant a license without violating the terms of any written agreement with a Third Party, and/or incurring any payment obligation to
a Third Party. With respect to Confidential Information, as set forth in Section 9.3, “Control” means that the Disclosing Party is authorized to disclose such information without violating any obligations of confidentiality to
a Third Party. 
 1.7 “Cover” means, with respect to a Valid Claim and a Licensed Product, that the manufacture, use, offer for sale, sale,
or import of such Licensed Product would, but for licenses granted under this Agreement or a judicially created or statutory exemption (including, but not limited to, experimental use or those exemptions provided in 35 U.S.C. § 271(e)(1) or in
similar provisions of applicable laws in jurisdictions other than the United States), infringe such Valid Claim; provided, however, that in determining whether a pending Valid Claim would be infringed, such Valid Claim shall be treated as if issued
in the form then currently being prosecuted. “Covered” and “Covering” shall have the correlative meaning. 
 1.8
“Field” means the use of T cells, natural killer (NK) cells, and/or induced pluripotent stem cell (iPSC)-derived cells for allogeneic CD371-targeted cell therapy. 

1.9 “Knowledge” means the knowledge of the [***] responsible for this Agreement after reasonable inquiry of the named inventors of the
Licensed Patent Rights and/or [***], as applicable, and the actual knowledge of the [***]. 
 1.10 “Licensed
Know-How” means the non-public information set forth on Exhibit A attached hereto, which exists as of the Effective Date. Within [***] calendar days of
the Effective Date of this Agreement, MSK will transfer to LICENSEE the Licensed Know-How. The Parties may, by mutual agreement, amend Exhibit A during the Term of this Agreement to add after-arising know-how; provided, however, that neither Party is under an obligation to so amend Exhibit A. 
 1.11
“Licensed Materials” means the biological materials set forth on Exhibit B attached hereto. Within [***] calendar days of the Effective Date of this Agreement, MSK will provide LICENSEE the Licensed Materials. 

1.12 “Licensed Patent Rights” means the U.S. provisional patent applications listed in Exhibit C attached hereto; as well as any
continuations, divisions, continuations-in-part, substitutions, registrations, reissues, reexaminations, confirmations, renewals, and extensions thereof; foreign
counterparts of any of the foregoing; and any and all patents issued thereon. 
 1.13 “Licensed Rights” means, collectively, the Licensed Know-How, Licensed Materials, and Licensed Patent Rights. 
 1.14 “Licensed Product” means any
CD371-targeted cell therapy in the Field (a) Covered by a Valid Claim of the Licensed Patent Rights, and/or (b) made or developed using the Licensed Know-How and/or Licensed Materials. [***]. 

1.15 “Net Sales” means, with respect to any and all Licensed Products, gross invoiced amounts for Licensed Products sold by LICENSEE, its
Affiliates, and Sublicensees to Third Parties, less applicable [***]. 
 [***] 

  
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 Combination Products. If a Licensed Product is sold as a Combination Product (as defined below), the
Net Sales of such Combination Product for the purpose of calculating royalties for sales of such Combination Product shall be determined as follows: [***]. 

[***] 
 1.16 “Sublicensee” means any person or
business entity to which LICENSEE or its Affiliates has granted (directly or through another sublicensee) a sublicense, covenant not to sue, or other immunity under any of the Licensed Rights. For clarity, a distributor or sales entity of Licensed
Products for LICENSEE is not a Sublicensee. 
 1.17 “Sublicensee Income” means all upfront cash and/or equity consideration received by
LICENSEE from a Sublicensee, but excluding [***]. 
 [***] 

1.18 “Term” means the period beginning on the Effective Date of this Agreement and ending on the later of (a) the expiration of the last
Valid Claim Covering the composition, manufacture, or use of any Licensed Product; or (b) twelve (12) years from the first commercial sale of the first Licensed Product by LICENSEE, its Affiliate, or Sublicensee, unless earlier terminated
pursuant to Article 16. 
 1.19 “Territory” means worldwide. 

1.20 “Third Party” means any person or entity other than LICENSEE or its Affiliates, on the one hand, and MSK and its Affiliates, on the
other hand. 
 1.21 “Valid Claim” means (a) an issued and unexpired claim of a patent that has not been held unenforceable or invalid
by a decision of a court or other governmental agency of competent jurisdiction, unappealable or unappealed within the time allowed for appeal, and that has not been admitted to be invalid or unenforceable through abandonment, reissue, disclaimer,
or otherwise; or (b) a pending patent application that has not been irretrievably cancelled, withdrawn, or abandoned and that has been pending for less than [***] years from the earliest claimed priority date. 

ARTICLE 2 - GRANT OF LICENSE; COVENANT NOT TO SUE; 

[***] 
 2.1 License Grant. In consideration
of LICENSEE’s satisfaction of all of its obligations hereunder, MSK hereby grants to LICENSEE an exclusive (even as to MSK except as explicitly reserved in Section 2.2), royalty-bearing license, with the right to sublicense through
multiple tiers pursuant to Article 3, to make, have made, use, sell, offer for sale, import, and export Licensed Products in the Territory under the Licensed Rights. LICENSEE (i) shall not, and shall cause its Affiliates to not, use the
Licensed Rights outside the Field, and (ii) shall contractually prohibit its Sublicensees from using the Licensed Rights outside the Field. 

[***] 
 2.3 Covenant Not to Sue. Additionally, provided
LICENSEE, its Affiliates, and any Sublicensees are in compliance with this Agreement, MSK hereby covenants not to sue LICENSEE, its Affiliates, and Sublicensees during the Term of this Agreement on account of the use, manufacture, sale, offer for
sale, import, or export of a Licensed Product for which royalties on Net Sales are due under Section 1.15 (including exemptions set forth therein) for infringement of a patent naming one or more inventors from the [***] that issues from an
application having an earliest-claimed priority date less than [***] from the Effective Date that claims expressly the sequence of an scFv within the Licensed Rights. 

2.4 No Implied Rights. LICENSEE acknowledges that the licenses granted herein and the covenant not to sue are limited to the Field. Accordingly, except
for the licenses expressly granted herein and the covenant not to sue granted herein, LICENSEE agrees that no right, title, or interest of any nature whatsoever is granted whether by implication, estoppel or otherwise. Furthermore, nothing in this
Agreement shall prevent or restrict MSK from granting licenses to Third Parties outside of the Field during the Term of this Agreement in the Territory. 

  
 - 4 - 

 [***] 
 [***]

 ARTICLE 3 - SUBLICENSES 
 3.1
Grant of Sublicenses. Subject to Sections 3.2 and 3.3, LICENSEE may grant sublicenses through multiple tiers at its sole discretion. 
 3.2
Binding Terms on Sublicensees. Any and all sublicense agreements shall by its terms bind the Sublicensee to the following Articles and Sections of this Agreement: the applicable DEFINITIONS in Article 1; Article 3 (SUBLICENSES); Article 9
(CONFIDENTIALITY); Article 13 (COMPLIANCE WITH LAW); Sections 2.1 (License Grant), 2.2 (Reserved Rights), 2.3 (Covenant Not to Sue), and 2.4 (No Implied Rights); Section 11.1 (Indemnification by LICENSEE); Section 14.3 (Non-Use of Names); and Section 16.7 (Effect on Sublicensees); and shall provide that MSK is a Third-Party beneficiary of such sublicense agreement. 

3.3 Sublicense Agreements. LICENSEE shall, within [***] calendar days of execution, provide to MSK a confidential copy of all sublicensing agreements
entered into by LICENSEE that include the Licensed Rights. LICENSEE may redact those portions of such sublicensing agreements that do not relate to payments or other obligations due to MSK, provided that outside counsel for MSK has the right to
review unredacted copies of such agreements solely to ensure compliance with this Agreement; provided, however, that MSK’s outside counsel may not share the redacted portions of such sublicensing agreements with MSK. Additionally, LICENSEE
shall provide MSK with a copy of any notice of breach or termination sent to or received from a Sublicensee within [***] calendar days to the extent such notice of breach relates to the Licensed Rights or payments owed thereon. 

ARTICLE 4 - DILIGENCE 
 During the Term,
LICENSEE shall use Commercially Reasonable Efforts to research, develop, and commercialize [***] Licensed Product in the United States and in [***] of the following European countries: [***], and the following development milestones shall be met by
LICENSEE, its Affiliates, or its Sublicensees: 
 [***] 

ARTICLE 5 - PAYMENTS 
 5.1 For the rights,
privileges, and licenses granted hereunder, LICENSEE shall pay to MSK, in the manner hereinafter provided, the following: 
 (a) Initial License Fee of
Cash and Equity. LICENSEE shall 
 (i) pay to MSK a nonrefundable and noncreditable initial license fee of Five Hundred Thousand U.S.
Dollars ($500,000) due within [***] business days of the Effective Date of this Agreement; and 
 (ii) issue to MSK 370,845 shares of
LICENSEE’s common stock, pursuant to a separate subscription agreement in the form set forth in Exhibit F attached hereto between LICENSEE and MSK, within [***] calendar days of the Effective Date of this Agreement. [***]. 

(b) Annual License Fee. Commencing on the first anniversary of the Effective Date of this Agreement and due on or before each subsequent anniversary
thereafter until the first commercial sale of the first Licensed Product, LICENSEE shall pay MSK an annual license fee of [***]. The annual license fee shall be noncreditable against any other obligations hereunder. 

  
 - 5 - 

 (c) Royalties. During the Term of this Agreement, LICENSEE shall pay MSK a royalty on Calendar Year
annual Net Sales of Licensed Products at the rates set forth below: 
 [***] 

 

			
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]

 [***] 
 (d)
Clinical and Regulatory Milestones. The following milestone payments shall be due once for each separate Licensed Product. Within [***] calendar days of the achievement of any of the following milestones by LICENSEE, or within [***] calendar
days of the occurrence of any of the milestones achieved by LICENSEE’s Affiliate or Sublicensee, LICENSEE shall notify MSK of the achievement of such milestone and pay MSK the applicable milestone payment: 

[***] 
 (e) Commercial Milestones. The
following milestone payments shall be due once for each separate Licensed Product. Within [***] calendar days of the achievement of any of the following milestones by LICENSEE, or within [***] calendar days of the occurrence of any of the milestones
achieved by LICENSEE’s Affiliate or Sublicensee, LICENSEE shall notify MSK of the achievement of such milestone and pay MSK the applicable milestone payment: 

[***] 
 (f) Sublicensee Income. LICENSEE
shall pay to MSK a portion of Sublicensee Income within [***] calendar days after LICENSEE receives such Sublicensee Income as follows: 

[***] 
 (g) Success Payment Amounts; Change
of Control Payment. As further set forth on Exhibit D attached hereto, MSK shall be eligible to receive certain Success Payment Amounts (as defined on Exhibit D) and a Change of Control Payment (as defined in Exhibit D) from
LICENSEE in an aggregate amount not to exceed Thirty-Five Million U.S. Dollars ($35,000,000) based on the value of LICENSEE’s stock reaching certain multiples, as determined in accordance with Exhibit D, within a time interval commencing
upon the date the first patient is dosed in the first Phase 1 clinical trial of the first Licensed Product (“Initial Date”) and ending upon the earlier of (a) the third (3rd) anniversary of receipt of Biologics License
Application approval by the FDA for the first Licensed Product, or (b) ten (10) years from the date the first patient is dosed in the first Phase 1 clinical trial of a Licensed Product (“Time Interval”). MSK shall not be eligible to
receive Success Payment Amounts or a Change of Control Payment outside of the Time Interval or during an uncured Major Breach pursuant to Section 16.5. 

5.2 Method of Payment. Except as permitted by Exhibit D with respect to Success Payment Amounts, all payments due under this Agreement shall be
made in the legal currency of the United States and shall be made by bank wire transfer in immediately available funds pursuant to MSK’s wire instructions, which MSK shall provide to LICENSEE within [***] business days of the Effective Date of
this Agreement. If any currency conversion shall be required in connection with the calculation of amounts payable hereunder, such conversion shall be calculated using the average interbank exchange rate during the applicable Calendar Quarter. 

5.3 Interest on Late Payments. Any payments or portions thereof due hereunder which are not paid when due shall bear interest equal to the lesser of
the rate equal to prime rate effective for the date that payment was due, as published by The Wall Street Journal, U.S., Internet Edition, on the date such payment was due, plus an additional [***], or the maximum rate permitted by applicable
laws, calculated on the number of days such payment is delinquent. 

  
 - 6 - 

 5.4 Tax Withholding. Each Party shall be responsible for its own taxes due under this Agreement.
LICENSEE shall make payments due under Article 5 or Section 7.1 in full, without deduction or withholding for wire transfer fees. The Parties will cooperate to prevent or minimize the need for any withholding, and, at the request of
LICENSEE, MSK will provide LICENSEE with documents evidencing its tax status in the United States. Any withholding or other tax that is required by law to be withheld with respect to payments owed by LICENSEE shall be deducted by LICENSEE from such
payment prior to remittance and paid over to the relevant taxing authorities when due. LICENSEE shall provide MSK with evidence of any such taxes withheld and of payment thereof within [***] calendar days of payment, and MSK shall seek to obtain the
release of any such withheld amounts from the taxing authority. At MSK’s request, LICENSEE shall provide MSK with reasonable assistance to release the withheld amount to MSK. If any amount remains withheld and is not released to MSK within
[***] months of the payment due date, then LICENSEE shall pay to MSK the amount that is still withheld, and entitlement to receive such withheld amount from the pertinent taxing authority shall be assigned by MSK to LICENSEE (or paid over by MSK to
LICENSEE if the taxing authority releases it directly to MSK). 
 ARTICLE 6 - RECORDS AND REPORTS 

6.1 Books and Records. LICENSEE shall keep, and shall require its Affiliates and Sublicensees to keep, complete and accurate books and records relating
to the sale of Licensed Products, as used in the calculation of Calendar Quarter reports under Section 6.2 (including, but not limited to, calculation of Net Sales pursuant to Section 1.15). LICENSEE shall permit an independent
qualified public accounting firm engaged by MSK to examine LICENSEE’s books and records (which are Confidential Information of LICENSEE) at any reasonable time during business hours upon [***] calendar days’ prior written notice, but only
with respect to books and records pertaining to the [***] years prior to the end of the most recently completed Calendar Quarter. The foregoing right of review may be exercised by MSK only once during each Calendar Year and may be exercised only
once with respect to any records provided for a particular Calendar Quarter. LICENSEE may require that the applicable accountants conducting the audit enter into a standard confidentiality agreement with LICENSEE. The results of any such examination
and review will be shared with LICENSEE within [***] calendar days after receipt thereof by MSK. MSK shall bear the cost of any such examination and review; provided that if the inspection and audit shows an underpayment of amounts payable hereunder
of [***] or more of the amount due for the applicable Calendar Quarter, then LICENSEE shall reimburse MSK within [***] calendar days of receipt of an invoice for all reasonable costs incurred in connection with such examination. LICENSEE shall pay
to MSK the amount of any underpayment revealed by such examination, in addition to interest owed from the date(s) such underpayment(s) were due, within [***] calendar days of receipt of an invoice from MSK for such underpayment and interest. If an
overpayment is revealed by such examination, LICENSEE may apply the amount of such overpayment to any payments due to MSK under Article 5, but in no event shall MSK be required to make a payment to LICENSEE. 

6.2 Calendar Quarter Reports. Within [***] calendar days after the end of the first Calendar Quarter in which LICENSEE, its Affiliates or Sublicensee
is selling a Licensed Product and within [***] calendar days after the end of each Calendar Quarter thereafter during the Term of this Agreement, LICENSEE shall deliver to MSK (a) a detailed report specifying in the aggregate
(i) total invoiced amounts to Third Parties for Licensed Products sold by LICENSEE, its Affiliates, and Sublicensees; and (ii) amounts deducted by category (as defined in Section 1.15) from gross invoiced amounts
to calculate Net Sales of the Licensed Products; and (b) payment of royalties due; provided, however, for the fourth Calendar Quarter of each Calendar Year, LICENSEE will adjust the amount of royalties due in accordance with
Section 5.1(c) for that Calendar Year. In the event that LICENSEE, its Affiliates, or Sublicensees reduces the royalty payment to MSK in accordance with Section 5.1(c)(ii) or (iii), LICENSEE shall furnish reasonably detailed documentation
in its Calendar Quarter reports of any such Third-Party royalty payments. All such Calendar Quarter reports and the information contained therein shall be deemed to be the Confidential Information of LICENSEE. 

ARTICLE 7 - FILING, PROSECUTION, AND MAINTENANCE 

OF LICENSED PATENT RIGHTS 
 7.1 Patent
Cost Reimbursement. 
 (a) Past Costs. LICENSEE shall reimburse MSK for [***] of all past out-of-pocket patent costs for the Licensed Patent Rights within [***] calendar days of receiving itemized past patent costs (including outside counsel invoices),

  
 -7- 

 
such amount agreed to between the Parties to be [***]. If requested in writing by MSK, LICENSEE shall, for MSK’s convenience, make the payment required by this Section 7.1(a) directly
to MSK’s outside counsel, and such payment shall satisfy LICENSEE’s reimbursement obligation under this Section 7.1(a). 
 (b) Ongoing
Cost Allocation. LICENSEE shall, during the Term of this Agreement, pay a proportion, based on the formula below, of the out-of-pocket expenses borne by MSK for
filing, prosecuting, and maintaining patents and patent applications within the Licensed Patent Rights throughout the Territory through MSK’s outside patent counsel. LICENSEE’s proportion of the patent costs shall be equal to [***] 

7.2 Control; Participation Rights. [***] 
 7.3 Common
Legal Interest. The Parties agree that they share a common legal interest in obtaining valid and enforceable patents. 
 7.4 Challenge to Licensed
Patent Rights. [***] 
 ARTICLE 8 - INFRINGEMENT OF LICENSED PATENT RIGHTS 

8.1 Notice of Third-Party Infringement. Each Party shall notify the other Party if it becomes aware of patent infringement of the Licensed Patent
Rights by a Third Party. 
 8.2 Enforcement and Defense. [***] shall have the first right, but not the obligation, for the initiation, defense, and
management of any legal proceeding relating to the Licensed Patent Rights (including without limitation any declaratory judgment action, patent infringement action, opposition, inter partes review or post-grant review, nullity proceeding, and the
like) (“Patent Action”) in the Field, and will be responsible for all expenses related thereto. [***] shall join in any such action, at [***]’s request and expense. If [***] does not wish to exercise either of the foregoing rights, it
shall provide [***] with written notice within [***] calendar days of becoming aware of Third-Party infringement or commencement of a legal proceeding against the Licensed Patent Rights that [***] declines such right, and [***] shall have the right,
but not the obligation, to prosecute or defend the action at its own expense without joinder of [***]. 
 8.3 Cooperation: Settlement. To the extent
either Party conducts any Patent Action in the Field, it shall keep the other Party reasonably informed of such proceedings. The other Party shall reasonably cooperate, at the expense of the requesting Party. Notwithstanding anything in this
Agreement to the contrary, no settlement, consent judgment, or other voluntary final disposition of any action by [***] that admits or impairs the invalidity, unenforceability, or scope of the Licensed Patent Rights may be entered into without the
prior written consent of [***] in its sole and absolute discretion. 
 In the event that [***] conducts a Patent Action outside the Field, it shall promptly
notify [***], and the Parties shall consult from time to time to keep [***] reasonably apprised of such Patent Action. Any information that is provided by [***] to [***] at [***]’s request shall be deemed to be Confidential Information of
[***]. [***] shall not in such proceeding cancel or disclaim any issued claim of the Licensed Patent Rights that is directed to the Field without the prior written approval of [***]. 

[***] 
 8.4 Costs and Recoveries. All costs of any action
by either Party to enforce, or to defend against a challenge to, the Licensed Patent Rights shall be borne by such Party, which shall keep any sums recovered or obtained in connection therewith (whether as damages, reasonable royalties, license
fees, or otherwise in judgment or settlement derived therefrom) [***]. 
 ARTICLE 9 - CONFIDENTIALITY 

9.1 Use of Confidential Information. Each Party agrees that Confidential Information of the other Party disclosed to it or to its employees under this
Agreement shall, for a period of [***] years after expiration or termination of this 

  
 - 8 - 

 
Agreement (a) be used only in connection with the legitimate purposes of this Agreement; (b) be disclosed only to those persons set forth in Section 9.3; (c)
be safeguarded with the same care normally afforded confidential information in the possession, custody or control of the Party holding the Confidential Information but no less than reasonable; and (d) not be disclosed, divulged, or
otherwise communicated except with the express written consent of the Disclosing Party, except as set forth below. 
 9.2 Exceptions. Confidential
Information will not include any information that the Receiving Party can document by competent evidence (a) is or becomes generally known to the public without violation of this Agreement by the Receiving Party or its Representatives;
(b) is in the rightful possession of the Receiving Party without breach of any confidentiality obligations at the time of disclosure by the Disclosing Party to the Receiving Party; (c) is obtained by the Receiving Party from
a Third Party without an accompanying duty of confidentiality and without a breach of such Third Party’s obligations of confidentiality; and/or (d) is independently developed by the Receiving Party without use of the Disclosing
Party’s Confidential Information. 
 9.3 Non-Disclosure and Non-Use Obligations. The Receiving Party will restrict the possession, knowledge,
and use of Confidential Information to its directors, officers, employees, advisers and consultants, potential and existing investors in the Receiving Party (including potential purchasers of milestones and royalties due MSK), potential and existing
sublicensees and Affiliates of LICENSEE, and entities Controlled by the Receiving Party who (a) have a need to know the Confidential Information for the benefit or potential benefit of the Receiving Party; (b) are informed of the
confidential nature of the Confidential Information; and (c) have obligations with respect to the Confidential Information that are consistent with this Agreement (collectively, “Representatives”). The Receiving Party shall be
responsible for its Representatives’ compliance with this Agreement. The Receiving Party and its Representatives shall not, except as otherwise agreed herein or as permitted by applicable laws (i) disclose any Confidential
Information of the Disclosing Party to Third Parties; (ii) use any Confidential Information of the Disclosing Party except as is necessary to perform the Receiving Party’s obligations under this Agreement; nor
(iii) reverse engineer, disassemble, or decompile any prototypes, software, samples, or other tangible objects that embody the Disclosing Party’s Confidential Information and that are provided to the Receiving Party under this
Agreement. 
 9.4 Maintenance of Confidentiality. The Receiving Party and its Representatives shall (a) take reasonable measures to protect the
secrecy of, and avoid disclosure and unauthorized use of, the Confidential Information of the Disclosing Party; without limiting the foregoing, the Receiving Party shall take at least those measures that it employs to protect its own confidential
information of a similar nature; (b) not make any copies of the Confidential Information of the Disclosing Party except as needed for the performance of the Receiving Party’s obligations or the exercise of the Receiving Party’s
rights under this Agreement or as otherwise approved in writing by the Disclosing Party; and (c) reproduce the Disclosing Party’s confidential rights notices on any such authorized copies in the same manner in which such notices
were set forth in or on the original. The Receiving Party shall promptly notify the Disclosing Party of any unauthorized use or disclosure, or suspected unauthorized use or disclosure, of the Disclosing Party’s Confidential Information of which
the Receiving Party or its Representatives become aware. Each Party will be responsible for any breach of this Agreement by its Representatives. 
 9.5
Export Restrictions. The Receiving Party agrees not to export or re-export any Confidential Information or product thereof in violation of U.S. or other export control laws or regulations. 

9.6 Compelled Disclosure. In the event the Receiving Party is legally required to disclose Confidential Information of the Disclosing Party by judicial
or governmental order, or in a judicial or governmental proceeding (“Compelled Disclosure”), the Receiving Party shall (a) give the Disclosing Party prompt notice of such Compelled Disclosure, prior to complying with such Compelled
Disclosure to the extent legally permissible; (b) cooperate with the Disclosing Party in the event that it elects to contest such Compelled Disclosure or seek a protective order with respect thereto; and (c) in any event only
disclose the exact Confidential Information or portion thereof specifically requested by the Compelled Disclosure. 
 9.7 Remedies. The Receiving
Party agrees that any violation of this Article 9 may cause irreparable injury to the Disclosing Party, entitling the Disclosing Party to seek injunctive relief in addition to all other legal remedies. 

9.8 Confidential Terms of this Agreement. Each Party shall treat the terms of this Agreement as the Confidential Information of the other Party.
Notwithstanding anything to the contrary, however, each Party may disclose the terms 

  
 - 9 - 

 
of this Agreement to its Representatives, to actual or potential investors or as part of a Change of Control process, and, in the case of LICENSEE, to its actual or potential Sublicensees;
subject to the restrictions set forth in this Article 9. 
 ARTICLE 10 - REPRESENTATIONS. WARRANTIES, AND COVENANTS 

10.1 General Representations and Warranties. Each Party represents and warrants to the other that (a) it is duly organized and validly existing
under the applicable laws of the jurisdiction of its incorporation and has full corporate power and authority to enter into this Agreement and to carry out the provisions hereof; (b) it is duly authorized to execute and deliver this
Agreement and to perform its obligations hereunder and the person executing this Agreement on its behalf has been duly authorized to do so by all requisite corporate action; (c) this Agreement is legally binding upon it and enforceable
in accordance with its terms, and the execution, delivery, and performance of this Agreement by it does not conflict with any agreement, instrument, or understanding, oral or written, to which it is a party or by which it may be bound, nor violate
any applicable laws; and (d) it is not aware of any action, suit, or inquiry or investigation instituted by any entity which questions or threatens the validity of this Agreement. 

10.2 MSK Representations, Warranties, and Covenants. [***] 

ARTICLE 11 - INDEMNIFICATIONS: INSURANCE 

11.1 Indemnification by LICENSEE. LICENSEE and its Affiliates shall indemnify, defend and hold harmless MSK, TDI, their respective Affiliates, and their
respective trustees, directors, officers, medical and professional staff, employees, and students, and their respective successors, heirs, and assigns (each an “MSK Indemnitee”), against all claims and expenses (including legal expenses
and reasonable attorneys’ fees) arising out of [***]; provided, however, that LICENSEE will not be obligated to indemnify, defend, and hold harmless any MSK Indemnitee against any Claim to the extent it arises out of, results from, or is
increased by MSK’s willful misconduct or gross negligence. MSK will give notice to LICENSEE of any Claims that might be covered by this Section 11.1 and LICENSEE will have the right to defend the same, including selection of counsel
reasonably acceptable to MSK (such approval to not be unreasonably withheld), and control of the proceedings; provided that LICENSEE will not, without the written consent of the MSK Indemnitee, settle or consent to the entry of any judgment with
respect to Claims (a) that do not release the MSK Indemnitee from all liability with respect to such Claims, or (b) that may materially adversely affect the MSK Indemnitee or under which the MSK Indemnitee would incur any obligation or
liability, other than one as to which LICENSEE has an indemnity obligation hereunder. MSK agrees to cooperate and provide reasonable assistance to such defense at LICENSEE’s expense. MSK at all times reserves the right to select and retain
separate counsel at its own expense to further defend MSK’s interests. 
 11.2 LICENSEE Insurance. During the Term of this Agreement, LICENSEE shall
obtain and carry in full force and effect general liability insurance that shall protect LICENSEE and MSK in regard to events covered by Section 11.1. Such insurance shall be written by a reputable insurance company and shall list MSK as an
additional insured. Upon written request, LICENSEE will provide MSK with a Certificate of Insurance, and LICENSEE will provide MSK with [***] calendar days’ written notice prior to any cancellation of such insurance. The limits of such
insurance shall not be less than [***] per occurrence with an annual aggregate of [***] for personal injury, death, or property damage. 
 11.3
Indemnification by MSK. MSK shall indemnify, defend and hold harmless (and cause its Affiliates to so indemnify, defend and hold harmless) LICENSEE, its Affiliates, and their respective directors, officers, and employees, and their respective
successors, heirs, and assigns (each a “LICENSEE Indemnitee”), against all Claims by a Third Party to the extent arising from [***]; provided, however, that MSK will not be obligated to indemnify, defend, and hold harmless any LICENSEE
Indemnitee against any Claim to the extent it arises out of, results from, or is increased by LICENSEE’s willful misconduct or gross negligence. LICENSEE will give notice to MSK of any Claims that might be covered by this
Section 11.3 and MSK will have the right to defend the same, including selection of counsel reasonably acceptable to LICENSEE (such approval to not be unreasonably withheld) and control of the proceedings; provided that MSK will not,
without the written consent of the LICENSEE Indemnitee, settle or consent to the entry of any judgment with respect to Claims (a) that do not release the LICENSEE Indemnitee from all liability with respect to such Claims, or
(b) that may materially adversely affect the LICENSEE Indemnitee or under which the LICENSEE Indemnitee would incur any obligation or liability, other than one as to which MSK has an indemnity

  
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obligation hereunder. LICENSEE agrees to cooperate and provide reasonable assistance to such defense at MSK’s expense. LICENSEE at all times reserves the right to select and retain separate
counsel at its own expense to further defend LICENSEE’s interests. 
 ARTICLE 12 - DISCLAIMER OF WARRANTIES: LIMITATION OF DAMAGES

 12.1 Disclaimer of Warranties. EXCEPT AS OTHERWISE EXPRESSLY SET FORTH IN THIS AGREEMENT, MSK MAKES NO REPRESENTATIONS, NO WARRANTIES, EITHER
EXPRESS OR IMPLIED, INCLUDING, WITHOUT LIMITATION, WARRANTIES OF FITNESS FOR A PARTICULAR PURPOSE, MERCHANTABILITY, VALIDITY OF LICENSED RIGHTS, VALIDITY OF LICENSED PATENT RIGHT CLAIMS ISSUED OR PENDING, OR THAT THE MANUFACTURE, SALE, OR USE OF THE
LICENSED PRODUCTS WILL NOT INFRINGE ANY PATENT, COPYRIGHT, TRADEMARK, OR OTHER PROPRIETARY RIGHTS. 
 12.2 Limitation of Damages. [***] 

ARTICLE 13 - COMPLIANCE WITH LAW 
 13.1
Export of Technical Data. It is understood that each Party may be subject to U.S. laws and regulations controlling the export of technical data, computer software, laboratory prototypes, and other commodities (including the Arms Export
Control Act, as amended and the Export Administration Act of 1979), and that its obligations hereunder are contingent on compliance with applicable U.S. export laws and regulations. The transfer of certain technical data and commodities may require
a license from the cognizant agency of the U.S. Government and/or written assurances by the other Party that the other Party shall not export data or commodities to certain foreign countries without prior approval of such agency. Neither Party
represents to the other Party that a license shall not be required nor that, if required, it shall be issued. 
 13.2 Compliance with Applicable
Laws. LICENSEE and its Affiliates shall comply, and shall contractually require Sublicensees to comply, with all applicable laws in connection with their respective use of the Licensed Rights and sale of Licensed Products. MSK shall comply, and
shall cause its Affiliates to comply, with all applicable laws in connection with their respective exercise of MSK’s reserved rights under Section 2.2 or MSK’s publication rights under Section 14.1. 

13.3 Marking of Licensed Products. To the extent required by law, or if the failure to mark would reduce the rights of MSK or LICENSEE to enforce the
Licensed Patent Rights against Third-Party infringers, LICENSEE shall mark, and shall contractually require its Affiliates and Sublicensees to mark, any Licensed Products with the appropriate Licensed Patent Rights. 

ARTICLE 14 - PUBLICATION: PRESS RELEASES: NON-USE OF NAMES 

14.1 Publication. [***] 
 14.2 Press Releases. On
or after the Effective Date of this Agreement, LICENSEE may issue a press release in the form set forth on Exhibit E attached hereto. Any additional information that a Party proposes to present or issue specifically regarding this Agreement
shall be provided to the other Party at least [***] business days in advance of the planned disclosure; provided, however, that LICENSEE may issue periodic public updates on its research, development, and commercialization of Licensed Products
without review by MSK. Additionally, either Party may disclose the name of the other Party and the existence of this Agreement as required by law or by a governmental agency (including, but not limited to, securities and regulatory filings). 

14.3 Non-Use of Names. Except as set forth above, neither Party shall use the name, trademarks, or logos of the
other Party nor of any of their employees in any press release, advertising, or promotional or sales literature without prior written consent of the other Party. 

  
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 ARTICLE 15 - ASSIGNMENT 

Neither Party may assign or delegate any or all of its rights or obligations under this Agreement, or transfer this Agreement, without the prior written
consent of the other Party, except that (a) MSK shall have the right to assign any of its rights, delegate any of its obligations, or transfer this Agreement without such consent (i) to an Affiliate, or (ii) as part of a Change of
Control; (b) LICENSEE shall have the right to assign any of its rights, delegate any of its obligations, or transfer this Agreement without such consent (i) to an Affiliate, or (ii) as part of a Change of Control; and (c) MSK may
without consent of LICENSEE freely assign all or any portion of the payments due under this Agreement to a Third Party. Any assignment by a Party shall bind its assignee to all provisions of this Agreement. Furthermore, the covenant not to sue set
forth in Section 2.3 shall be transferable to and for the benefit of an assignee of this Agreement by LICENSEE upon assignment of this Agreement as permitted under this Article 15 and shall be binding with respect to any assignee of LICENSEE
upon assignment of this Agreement by LICENSEE permitted under this Article 15. Any assignment, delegation, or transfer by any Party in violation of this Article 15 shall be void and of no effect. 

ARTICLE 16 - TERMINATION 
 16.1
Termination by LICENSEE. (a) LICENSEE may terminate this Agreement upon ninety (90) calendar days’ prior notice to MSK. Following termination under this Section 16.1, LICENSEE and its Affiliates shall not
(i) exploit the Licensed Rights, or (ii) make, have made, sell, offer to sell, use, export, or import any product that would be a Licensed Product but for LICENSEE’s termination under this Section 16.1. (b)
If LICENSEE is in material breach of this Agreement at the time it gives notice of termination under this Section 16.1, or if the dispute resolution process of Section 18.10 has commenced at the time of such notice, a
termination by LICENSEE under this Section 16.1 shall not divest MSK of any rights or remedies that it may have against LICENSEE on account of LICENSEE’s breach. 

16.2 Bankruptcy or Cessation of Business. MSK may terminate this Agreement upon written notice to LICENSEE if (a) a petition in bankruptcy is
filed against LICENSEE and is consented to, acquiesced in or remains undismissed for [***]; (b) LICENSEE makes a general assignment for the benefit of creditors, or a receiver is appointed for LICENSEE, and LICENSEE does not return to solvency
before the expiration of a [***] period; or (c) LICENSEE makes a filing with a governmental agency that LICENSEE has ceased to do business. 

16.3 Nonpayment. If LICENSEE fails to pay MSK any payments under Article 5 or Section 7.1, and such payments remain past due for more than [***]
MSK shall have the right to terminate this Agreement after an additional [***] written notice, unless LICENSEE pays to MSK within the [***] notice period, all payments past due together with any interest due. A dispute concerning LICENSEE’s
payment obligations shall be subject to the dispute resolution procedure of Section 18.10. 
 16.4 Criminal Activity. MSK may terminate this
Agreement upon immediate written notice to LICENSEE if LICENSEE is convicted in a final judgment that cannot be appealed of a felony relating to the manufacture, use, or sale of Licensed Products in any jurisdiction where LICENSEE manufactures,
uses, or sells Licensed Products. 
 16.5 Breach. (a) In addition to any other termination right specified in this Agreement, either Party may
terminate this Agreement upon [***] written notice to the other Party, if the other Party materially breaches a provision of this Agreement, unless the other Party cures any such breach prior to the expiration of the [***] period. (b) In
the event MSK materially breaches (i) Section 2.1 by granting a license of the Licensed Rights to a Third Party in the Field, [***], LICENSEE may, as an alternative to terminating this Agreement, maintain this Agreement;
provided, however that during the period of an uncured Major Breach by MSK, MSK shall not be eligible for any Success Payment Amounts or Change of Control Payment. If LICENSEE chooses to maintain this Agreement during the period of an uncured Major
Breach by MSK, LICENSEE will so notify MSK within [***] [***] after the [***] period set forth in Section 16.5(a). If and when MSK cures the Major Breach, MSK shall be eligible for any future Success Payment Amounts or Change of Control
Payment from the date of cure of the Major Breach to the end of the Time Interval (which shall not be extended). 
 16.6 Success Payment Amounts; Change
of Control Payment. (a) LICENSEE’s obligation to pay the Success Payment Amounts and the Change of Control Payment set forth in Section 5.1(g) and Exhibit D shall terminate immediately following the closing of a Change of
Control of LICENSEE, with the sole exception of any Success 

  
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Payment Amount or a Change of Control Payment that is due and payable to MSK as a result of such Change of Control. (b) The Success Payment Amounts and the Change of Control Payment
will not survive in the event that LICENSEE terminates this Agreement pursuant to Section 16.1(a), except under the circumstances set forth in Section 16.1(b) and only if LICENSEE has no Sublicensees at the time of
termination. 
 16.7 Accrued Obligations. Expiration or termination of this Agreement for any reason shall not release LICENSEE from any obligation
or liability that, at the time of such expiration or termination, has already accrued to MSK or which is attributable to a period prior to such expiration or termination; specifically any accrued payments due to MSK by LICENSEE under Sections 5.1(b)
through 5.1(g) (and Sections 5.3 and 5.4, as applicable); Section 6.2; and Section 7.1(b). 
 16.8 Effect on Sublicensees. [***]

 16.9 Survival. Upon any expiration or termination of this Agreement, the following Articles, Sections and Exhibits of this Agreement shall
survive: the applicable DEFINITIONS in Article 1; Articles 9 (CONFIDENTIALITY); 11 (INDEMNIFICATIONS; INSURANCE); 12 (DISCLAIMER OF WARRANTIES; LIMITATION OF DAMAGES); 17 (NOTICES AND OTHER COMMUNICATIONS); and 18 (MISCELLANEOUS PROVISIONS);
Sections 6.1 (Books and Records); 16.6 and Exhibit D (Success Payment Amounts; Change of Control Payment), unless expressly terminated by LICENSEE under Section 16.1(a) or under Section 16.5; 16.7 (Accrued Obligations); and 16.9
(Survival). 
 ARTICLE 17 - NOTICES AND OTHER COMMUNICATIONS 

Except for payments, any notice, request, delivery, approval, or consent required or permitted to be given under this Agreement shall be in writing and shall
be deemed to have been sufficiently given if delivered in person, transmitted by facsimile or electronic mail (receipt verified) or by express courier service (signature required), or five (5) business days after it was sent by registered
letter, return receipt requested (or its equivalent), to the Party to which it is directed at its address shown below or such other address as provided in writing by one Party to the other Party. 

In the case of MSK: 
 [***] 

In the case of LICENSEE: 
 [***] 

ARTICLE 18 - MISCELLANEOUS PROVISIONS 

18.1 Governing Law. This Agreement shall be construed, governed, interpreted, and applied in accordance with the laws of the State of New York, without
giving effect to any choice or conflict of law principles, except that questions affecting the construction and effect of any patent shall be determined by the law of the country in which the patent was filed or granted. 

18.2 Jurisdiction. The state and federal courts located in the State of [***] with jurisdiction in [***] shall have exclusive jurisdiction of any
claims or actions between the Parties, their successors and assigns, arising out of or relating to this Agreement, and each Party, their successors and assigns consents to venue and personal jurisdiction of those courts for the purpose of resolving
any such disputes. 
 18.3 Severability. Except to the extent a provision is stated to be essential, or otherwise to the contrary, the provisions of
this Agreement are severable, and in the event that any provisions of this Agreement shall be determined to be invalid or unenforceable under any controlling body of the law, such invalidity or unenforceability shall not in any way affect the
validity or enforceability of the remaining provisions hereof. 

  
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 18.4 Waiver. The failure of either Party to assert a right hereunder or to insist upon compliance
with any term or condition of this Agreement shall not constitute a waiver of that right or excuse a similar subsequent failure to perform any such term or condition by the other Party. 

18.5 Counterparts. This Agreement may be executed in any number of counterparts, including scanned PDF documents or electronic signatures, and each of
such counterparts shall for all purposes be an original and all such counterparts shall together constitute but one and the same agreement. 
 18.6
Entire Agreement: Amendments. This Agreement, including Exhibits A, B, C, D, E, and F (which exhibits are incorporated herein by reference), constitutes the entire understanding between the Parties
with respect to the subject matter hereof, and supersedes any and all prior and contemporaneous negotiations, representations, agreements, term sheets, and understandings, written or oral, that the Parties may have reached with respect to the
subject matter hereof, including but not limited to [***]. This Agreement may only be modified or supplemented in a writing expressly stated for such purpose and signed by authorized representatives of the Parties. 

18.7 No Reliance. Each Party hereby acknowledges that in executing this Agreement it is not relying on and has not relied on any representation or
statement by the other Party, other than statements contained in this Agreement. 
 18.8 Relationship between the Parties. The relationship between
the Parties under this Agreement is that of independent contractors. Nothing contained in this Agreement shall be construed to create a partnership, joint venture, or agency relationship between the Parties. No Party is a legal representative of any
other Party, and no Party can assume or create any obligation, liability, representation, warranty, or guarantee, express or implied, on behalf of the other Party for any purpose whatsoever. 

18.9 Force Majeure. With the exception of payment of amounts due under Article 5, in the event either Party hereto is prevented from or delayed in the
performance of any of its obligations hereunder, other than the obligation to pay money, by reason of acts of God, wars, strikes, civil unrest and riots, storms and other weather phenomena, fires, earthquakes, epidemics, pandemics, power shortages
or failures, failures of transportation or other governmental systems, postal and courier delays, and the like, the Party so prevented or delayed shall be excused from the performance of any such obligation for the period during which its
performance is prevented by the force majeure event. The Party affected by such force majeure shall provide the other Party with full particulars thereof as soon as it becomes aware of the same (including its best estimate of the likely extent and
duration of the interference with its activities), and shall use Commercially Reasonable Efforts to overcome the difficulties created thereby and to resume performance of its obligations as soon as practicable. 

18.10 Dispute Resolution. [***] 
 IN
WITNESS WHEREOF, an authorized representative of each Party has signed and dated this Exclusive License Agreement below. 
  

							
	CARIBOU BIOSCIENCES, INC.	 	MEMORIAL SLOAN KETTERING
		 		 	CANCER CENTER
				
	By:	 	 /s/ Rachel E. Haurwitz
	 	By:	 	 /s/ Gregory S. Raskin

	Rachel E. Haurwitz, Ph.D.	 	Gregory S. Raskin
	President & CEO	 	Vice President
		 		 	Technology Development
				
	Date:	 	November 13, 2020	 	Date:	 	November 13, 2020

  
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 Exhibit A 

Licensed Know-How 

[***] 

 Exhibit B 

Licensed Materials 
 [***]

 Exhibit C 

Licensed Patent Rights 

[***] 

 Exhibit D 

Success Payment Amounts; Change of Control Payment 

 Success Payment Amounts 

1. Initial Share Price Multiples Giving Rise to Success Payment Amounts. The Success Payment Amounts (as defined herein) shall be paid by LICENSEE upon
LICENSEE achieving a Subsequent Company Share Value (as defined herein) during the Time Interval (as defined in Section 5.1(g) of this Exclusive License Agreement) greater than or equal to the following multiples of the Initial Share Price (as
defined herein) determined as set forth in Section 4 of this Exhibit D. The amount (the “Success Payment Amounts”) LICENSEE shall be obligated to pay to MSK upon achieving a Subsequent Company Share Value equal to each
such multiple of the Initial Share Price are set forth in the following table: 
  

							
	Multiple of Initial Share Price that gives rise to a Success Payment Amount:	  	5X	  	10X	  	15X
	Success Payment Amounts payable to MSK:	  	 5X multiple
 Success Payment

Amount:
 $10,000,000
	  	 10X multiple
 Success Payment

Amount:
 $10,000,000
	  	 15X multiple
 Success Payment

Amount:
 $15,000,000

 The aggregate Success Payment Amounts and Change of Control Payment paid by LICENSEE to MSK shall in no event exceed
Thirty-Five Million U.S. Dollars ($35,000,000). 
 [***] 
 2.
Definitions. 
 (a) “Calculation Event” means a Qualified Equity Financing, a Qualified Debt Financing, a Change of Control, or an
IPO. 
 (b) “Change of Control” means, for purposes of this Exhibit D only, a Change of Control of LICENSEE and shall not include
any merger or consolidation involving LICENSEE or a subsidiary of LICENSEE in which the shares of capital stock of LICENSEE 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 [***], by voting power, of the capital stock of (1) the surviving or resulting corporation, 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. 

(c) “Qualified Equity Financing” means a Private Financing where LICENSEE sells preferred stock or common stock of LICENSEE. 

(d) “Qualified Debt Financing” means a Private Financing where LICENSEE sells debt securities convertible into LICENSEE’s preferred
stock or common stock at a fixed price determinable on the date of issuance. For the avoidance of doubt, the issuance of any debt security containing a valuation cap or other similar discount mechanism that is only applicable to a future valuation
or price per share after the issuance date of such debt security shall not be considered a Qualified Debt Financing. 
 (e) “Initial Share
Price” is $9.4379 per share (subject to appropriate adjustment in the event of any stock dividend, stock split, combination, or other similar recapitalization). 

(f) “IPO” means LICENSEE’s first sale of shares of LICENSEE’s common stock to the public in a firm commitment underwritten public
offering pursuant to an effective registration statement under the Securities Act of 1933, as amended. 
 (g) “Private Financing” means a
transaction or series of related transactions for capital raising purposes yielding gross proceeds to LICENSEE of at least [***]. For purposes of clarification, a Private Financing shall not include the issuance of any shares (i) to
LICENSEE’s service providers, (ii) to banks, equipment lessors, or other financial institutions or to real property lessors, pursuant to a debt financing (other than a Qualified Debt Financing), equipment

 
leasing, or real property transaction, (iii) pursuant to LICENSEE’s acquisition of another entity by merger, purchase of substantially all of the assets of another entity, or other
reorganization pursuant to a joint venture agreement, (iv) in connection with sponsored research, collaboration, technology/intellectual property licensing, development, marketing, or other similar arrangements or strategic partnerships, or
(v) pursuant to any settlement of any action, suit, proceeding, or litigation. 
 (h) “Subsequent Company Share Value Certificate”
means a certificate in the form set forth on Annex 1 attached hereto, issued by LICENSEE, setting forth and certifying the Subsequent Company Share Value calculated pursuant to Section 3 of this Exhibit D. 

(i) “45-Day VWAP” means the volume weighted average trading price of LICENSEE’s common stock
over the forty-five (45) trading day period immediately preceding the date of determination. 
 3. “Subsequent Company Share Value”
shall be a per share value determined as follows: 
 (a) Prior to the IPO. Prior to the IPO, the Subsequent Company Share Value shall be determined
at the closing of a Qualified Equity Financing or a Qualified Debt Financing. 
 (i) Qualified Equity Financing. In the case of a
Qualified Equity Financing, the Subsequent Company Share Value shall be equal to the lowest per share cash purchase price of LICENSEE’s preferred stock or common stock, as the case may be, sold in such Qualified Equity Financing. 

(ii) Qualified Debt Financing. In the case of a Qualified Debt Financing, the Subsequent Company Share Value shall be equal to the
fixed, per share conversion price of the debt securities sold in such Qualified Debt Financing determinable on the closing date of such Qualified Debt Financing. 

(b) At the IPO. At the IPO, the Subsequent Company Share Value shall be equal to the initial public offering price. 

(c) After the IPO. At all times following the date that is forty-five (45) trading days after the IPO, except at the closing of a Change of
Control, the Subsequent Share Value shall be equal to the 45-Day VWAP. 
 (d) At a Change of Control. In the
case of a Change of Control, the Subsequent Company Share Value shall be equal to the lowest amount per share of the proceeds distributed solely at the closing of such Change of Control to the holder of a share of LICENSEE’s Series B Preferred
Stock (or, as applicable, a share of LICENSEE’s common stock issued upon conversion of such share of Series B Preferred Stock). The amount deemed paid or distributed to the holders of shares of LICENSEE’s Series B Preferred Stock (or, as
applicable, shares of LICENSEE’s common stock issued upon conversion of such shares of Series B Preferred Stock) upon any such Change of Control shall be the cash plus the value of the property, rights, or securities paid or distributed to such
holders by LICENSEE or acquiring person, firm, or other entity at the closing of such Change of Control. The value of such property, rights, or securities shall be determined in good faith by the Board of Directors of LICENSEE. For purposes of
clarification, the Subsequent Company Share Value calculated pursuant to the preceding sentence shall not include proceeds from potential earn-outs, release of holdbacks/escrow amounts, contingent value rights, or similar contingent distributions.

 (e) All per share values referenced in this Exhibit D including but not limited to the Subsequent Company Share Value are subject to appropriate
adjustment in the event of any stock dividend, stock split, combination or other similar recapitalizations. 
 4. Determination of Subsequent Company
Share Value; Timing. The Subsequent Company Share Value shall be determined each time a Calculation Event occurs and at all times following the date that is forty-five (45) trading days after the IPO as described in Section 3(c) of
this Exhibit D. For clarity, payment to MSK of a previous Success Payment Amount shall not relieve LICENSEE’s obligations to make a Success Payment Amount in connection with any subsequent increases in the Subsequent Company Share Value
subject to the aggregate maximum of Thirty-Five Million U.S. Dollars ($35,000,000). 

  
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 5. Notices and Evidence of Subsequent Company Share Value. 

(a) Notice. LICENSEE shall provide MSK with a Subsequent Company Share Value Certificate no later than [***] following the occurrence of a Calculation
Event. In the case of the VWAP Notice (as defined herein), MSK shall provide LICENSEE with such VWAP Notice no later than [***] following the forty-fifth (45’) trading day of the forty-five (45) trading day time period that MSK used to
determine the 45-Day VWAP Value. 
 (b) Evidence of Subsequent Company Share Value. 

(i) Prior to the IPO. Prior to the IPO and in the case of either a Qualified Equity Financing or a Qualified Debt Financing, in
addition to the Subsequent Company Share Value Certificate provided pursuant to Section 5(a) herein, LICENSEE shall provide a redacted copy of the executed stock purchase agreement or convertible promissory note, as the case may be, for such
Qualified Equity Financing or Qualified Debt Financing reflecting the per share cash purchase price or prices or conversion price of LICENSEE’s securities sold in such Qualified Equity Financing or Qualified Debt Financing. The redactions of
the executed stock purchase agreement or convertible promissory note shall include, without limitation, the names and any other identifying information of the purchasers, the schedule of purchasers, exhibits, signature pages, and any representations
and warranties made by LICENSEE. The Subsequent Company Share Value set forth in the applicable Subsequent Company Share Value Certificate shall be the final value used for determining the applicable Success Payment Amount. 

(ii) Upon the IPO. For the IPO, the Subsequent Company Share Value set forth in the applicable Subsequent Company Share Value
Certificate shall be the final value used for determining the applicable Success Payment Amount. 
 (iii) Change of Control. In the
event of a Change of Control, the Subsequent Company Share Value set forth in the applicable Subsequent Company Share Value Certificate shall be the final value used for determining the applicable Success Payment Amount. 

(iv) After the IPO. In the event MSK determines that a Success Payment Amount is due at any time following the date that is forty-five
(45) trading days after the IPO, MSK shall provide LICENSEE with written notice in a timely manner as set forth in Section 5(a) of this Exhibit D containing MSK’s calculation of the
45-Day VWAP (such value, the “45-Day VWAP Value”) giving rise to the applicable Success Payment Amount obligation (the “VWAP Notice”),
and, unless LICENSEE disputes the calculations contained in the VWAP Notice in writing within [***] following LICENSEE’s receipt of the VWAP Notice (a “Dispute Notice”), the calculation of the
45-Day VWAP Value set forth in the VWAP Notice shall constitute the Subsequent Company Share Value. [***]. For purposes of clarification, LICENSEE shall have no obligation to monitor the 45-Day VWAP or provide MSK any notice in the event that a Success Payment Amount has arisen or may have arisen due to the 45-Day VWAP. 

6. Form of Payments; Timing of Payments. 
 (a) Form of
Payment. LICENSEE shall have the option to pay a Success Payment Amount to MSK in cash or, subject to applicable securities laws, in shares of LICENSEE’s common stock having a value equivalent to such Success Payment Amount (as determined
below). 
 (i) Stock Payment. If LICENSEE elects to pay a Success Payment Amount in shares of LICENSEE’s common stock, the
number of shares of LICENSEE’s common stock to be issued to MSK shall be calculated using a price per share equal to (i) if the Success Payment Amount is due as a result of a Qualified Equity Financing, a Qualified Debt Financing, or an
IPO, the Subsequent Company Share Value in such case giving rise to the obligation to pay such Success Payment Amount, or (ii) if the Success Payment Amount is due following the date that is forty-five (45) trading days after the IPO, the 45-Day VWAP Value set forth in the VWAP Notice. Shares of common stock issued by LICENSEE to MSK pursuant to this Section 6(a)(i) shall be subject to a subscription agreement in substantially the form set forth
as Exhibit F to the Exclusive License Agreement. LICENSEE shall have no obligation to register such shares for resale but shall use commercially reasonable efforts to assist with any legend removal as soon as lawful, subject to compliance
with applicable securities laws. 

  
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 (b) Timing of Payments. 

(i) Cash Payment Prior to the IPO or at the IPO. Prior to the IPO or at the IPO, if LICENSEE elects to pay a Success Payment Amount in
cash, such payment shall occur within [***] after the occurrence of the Calculation Event giving rise to such Success Payment Amount. 

(ii) Cash Payment After the IPO. Following the IPO, if LICENSEE elects to pay a Success Payment Amount in cash, such payment shall
occur within [***] after receipt of the VWAP Notice [***] or, in the case of a Success Payment Amount that has arisen as a result of a Change of Control, within [***] after the occurrence of such Change of Control. 

(iii) Stock Payment. Subject to applicable securities laws, payment of a Success Payment Amount in shares of LICENSEE’s common
stock shall occur within [***] after the occurrence of the Calculation Event giving rise to such Success Payment Amount or receipt of a VWAP Notice [***] as the case may be. 

  
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 Change of Control Payment 

1. Change of Control Payment. If, during the Time Interval, there is a Change of Control of LICENSEE, in addition to any Success Payment Amounts that
may be due as a result of such Change of Control, LICENSEE may have an obligation to pay to MSK an amount calculated in accordance with the following provisions (the “Change of Control Payment”); provided, however, that the sum of
the Change of Control Payments and Success Payment Amounts paid to MSK shall not exceed Thirty-Five Million U.S. Dollars ($35,000,000): 
 [***] 

2. Timing of Payment. The Change of Control Payment shall be due and payable within [***] [***] after the Change of Control occurs. 

[***] 

 Exhibit E 

LICENSEE Press Release 

 Caribou Biosciences Announces Licensing Agreement for scFvs Targeting CD371 to 

Enable Development of Allogeneic Cell Therapies 

BERKELEY, CA - November [    ], 2020 - Caribou Biosciences, Inc., a leading clinical-stage CRISPR genome editing biotechnology company,
announced today the execution of an exclusive license agreement with Memorial Sloan Kettering Cancer Center (MSK) under which Caribou has rights to fully human anti-CD371 scFvs and intellectual property related thereto in the field of allogeneic
CD371-targeted cell therapies including CAR-T, CAR-NK, or iPSC-derived cell products. The anti-CD371 scFvs were developed in the laboratory of Renier Brentjens, M.D.,
Ph.D. at MSK in collaboration with the Tri-Institutional Therapeutic Discovery Institute (Tri-I TDI). Tri-I TDI is a non-profit drug discovery company wholly owned by MSK, Weill Cornell Medicine, and The Rockefeller University (www.tritdi.org). MSK has the sole responsibility for licensing these scFvs and the related intellectual
property for commercialization. 
 “CD371, also known as CLL-1, is an attractive target for both acute myeloid
leukemia (AML) and myelodysplastic syndromes (MDS) due to its expression on these myeloid cancer cells, its enrichment in leukemic stem cells, and its absence on hematopoietic stem cells,” said Steven Kanner, Ph.D., Chief Scientific Officer of
Caribou. “Preclinical studies at MSK have demonstrated the antitumor efficacy of targeting CD371 in AML using these human scFvs in CAR-Ts.” 

In-licensing these anti-CD371 scFvs further expands Caribou’s pipeline of allogeneic cell therapies for
hematological malignancies. CB-010, Caribou’s lead allogeneic CAR-T program, targets CD19 and has been cleared by the FDA for clinical evaluation. CB-011, Caribou’s second allogeneic CAR-T therapy, targets BCMA. Caribou’s next-generation genome editing technologies enable high efficiency and specificity
multiplex engineering, which is critical for the manufacture of CB-010 and CB-011. Caribou implements multiple strategies to boost
CAR-T cell persistence to overcome T cell exhaustion and prevent rapid immune-mediated clearance. 
 “The
opportunity to exclusively access fully human CD371-specific antibody fragments is exciting and we look forward to utilizing them to develop allogeneic cell therapies to treat AML and/or MDS,” said Rachel Haurwitz, Ph.D., President and Chief
Executive Officer of Caribou. “The combination of these scFvs and Caribou’s next-generation genome editing platform is a promising approach to addressing these
difficult-to-treat myeloid malignancies with significant unmet medical need.” 

The financial terms of the deal were not disclosed. 
 About
Caribou Biosciences, Inc. 
 Caribou is a leading clinical-stage CRISPR genome editing biotechnology company founded by pioneers of CRISPR biology. The
company is developing an internal pipeline of off-the-shelf genome-edited CAR-T and natural killer (NK) cell therapies. 

For more information about Caribou, visit www.cariboubio.com and follow the Company @CaribouBio. 

“Caribou Biosciences” and the Caribou logo are registered trademarks of Caribou Biosciences, Inc. 

Required Memorial Sloan Kettering Cancer Center (MSK) Disclosure 

As a result of the licensing agreement with Caribou described herein, MSK has institutional financial interests related to the licensed technologies and will
be a Caribou stockholder. Researchers at MSK, including Dr. Brentjens, have rights to receive financial remuneration associated with the licensed intellectual property rights. 

Caribou Biosciences Media Contact: 
 [name] 

Ogilvy 
 [email] 

[phone] 

 Exhibit F 

Form of Subscription Agreement 

[***]EX-10.3

 Certain identified information has been excluded from this exhibit because it is both not material and
is the type that the registrant treats as private or confidential. Information that was omitted has been noted in this document with a placeholder identified by the mark “[***]”. 

Exhibit 10.3 

CONFIDENTIAL 
 SALE AND
ASSIGNMENT AGREEMENT 
 This Sale and Assignment Agreement (this “Agreement”), dated as of January 31, 2020 (the
“Effective Date”), is by and between ProMab Biotechnologies, Inc., having an address at 2600 Hilltop Drive, Richmond, CA 94806 (“ProMab”), and Caribou Biosciences, Inc., having a place of business at 2929 7th Street, Suite 105, Berkeley, CA 94710 USA (“Caribou”). ProMab and Caribou are each referred to herein individually as a “Party” and collectively as the “Parties.” 

WHEREAS, [***] 

WHEREAS, [***] 

WHEREAS, [***] 

NOW, THEREFORE, in consideration of the mutual covenants, terms, and conditions set forth herein, and for other good and valuable
consideration, the receipt and sufficiency of which are hereby acknowledged, the Parties hereto agree as follows: 
 ARTICLE 1 

DEFINITIONS 
 As used in
this Agreement, the following capitalized terms shall have the meanings indicated: 
 1.1 “Affiliate” means any corporation or
other business entity that, directly or indirectly, through one or more intermediaries, controls, is controlled by, or is under common control with a Party, but only for so long as such corporation or entity controls, is controlled by, or is under
common control with such Party. For purposes of this definition of an Affiliate, the term “control” means (a) the direct or indirect ownership of more than [***] of the stock having the right to vote for directors thereof, or
(b) the ability to otherwise control the decisions of the board of directors or equivalent governing body thereof. Affiliates excludes any other portfolio companies of investors that have invested in a Party. 

1.2 “Assigned Patent Rights” means those patent applications set forth on Exhibit A attached hereto as well as any
continuations, divisionals, continuations-in-part, substitutions, registrations, reissues, reexaminations, confirmations, renewals, and extensions thereof, and any
patents issuing therefrom; and foreign counterparts of any of the foregoing. 
 1.3 “Calendar Quarter” means four (4) periods
of three (3) consecutive months each, wherein each period shall be a quarter and shall end March 31, June 30, September 30, and December 31. 

1.4 “Calendar Year” means the time period from January 1 through December 31. 

1.5 “Controlled” for purposes of Section 2.4 means that ProMab has the legal authority or right (whether by ownership, license,
or otherwise) to grant to Caribou the covenant not to sue set forth in Section 2.4 without violating the terms of any agreement with any Third Party. 

 1.6 “Net Sales” means, with respect to any and all Products, gross invoiced
amounts for Products sold by Caribou, its Affiliates, and any direct and indirect sublicensees thereof, to Third Parties, less applicable [***]. 

1.7 “PMC306” means the humanized scFv of the anti-B cell maturation antigen (BCMA) chimeric
antigen receptor (CAR) designated by ProMab as PMC306 and defined by the Sequence. 
 1.8 “Product” means any product, the
manufacture, use, sale, offer for sale, importation, or exportation of which would infringe a Valid Claim of the Assigned Patent Rights. 

1.9 “Sequence” means the exact DNA and protein sequences of PMC306 as set forth on Exhibit B attached hereto and in the
Assigned Patent Rights. 
 1.10 “Term” means from the Effective Date of this Agreement until the expiration, abandonment, or
invalidation of the last patent within the Assigned Patent Rights. 
 1.11 “Third Party” means any person or entity other than
ProMab or Caribou or an Affiliate of either Party. 
 1.12 ”Valid Claim” means a claim of an issued, unexpired, and in-force patent that has not been revoked or held unenforceable or invalid by a decision of a court or other governmental agency of competent jurisdiction (which decision is not appealable or has not been appealed
within the time allowed for appeal), and which claim has not been disclaimed, denied, or admitted to be invalid or unenforceable through reissue, re-examination, supplemental examination, disclaimer, or
otherwise. For the sake of clarity, patent application claims are not included within the definition of Valid Claim. 
 ARTICLE 2 

ASSIGNMENTS 
 2.1
Assignment of PMC306. ProMab agrees to sell and assign, and hereby does sell and assign, to Caribou all rights, title, and interest in PMC306. No rights or interest of any kind in PMC306 are retained by ProMab. 

2.2 Assignment of Patent Rights. ProMab agrees to sell and assign, and hereby does sell and assign, to Caribou all rights, title, and
interest in the Assigned Patent Rights, including but not limited to enforcement rights and rights to future inventions or improvements derived from the Assigned Patent Rights. No rights or interest of any kind in the Assigned Patent Rights are
retained by ProMab. 
 2.3 Acknowledgement by Caribou Regarding PMC306 and the Assigned Patent Rights. By entering into this
Agreement, Caribou acknowledges that (a) ProMab has applied for both a provisional patent application (now expired) and a Patent Cooperation Treaty (PCT) application (currently pending) on PMC306 with the U.S. Patent and Trademark Office before
the Effective Date of this Agreement; and (b) ProMab makes no representations, warranties, or covenants that patents will issue on the Assigned Patent Rights. 

  
 - 2 - 

 2.4 Covenant Not to Sue. Additionally, ProMab hereby covenants not to sue Caribou,
its Affiliates, and any direct and indirect sublicensees thereof during the Term in the event that a Product or the use, manufacture, sale, offer for sale, importation, or exportation thereof infringes any intellectual property Controlled by ProMab.
This covenant not to sue shall be transferable to and for the benefit of an assignee of this Agreement by Caribou upon assignment of this Agreement as set forth in Section 9.2 and shall be binding with respect to any assignee of ProMab upon
assignment of this Agreement by ProMab as set forth in Section 9.2. 
 ARTICLE 3 

PAYMENTS AND REPORTS 
 3.1
Initial Assignment Fee. Caribou shall pay to ProMab a [***] within [***] calendar days of the Effective Date of this Agreement. Within [***] business days after the Effective Date of this Agreement, ProMab shall provide Caribou with wire
instructions for payments due by Caribou to ProMab under this Agreement. 
 3.2 Royalties. 

[***] 
  

			
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]

 [***] 
 (a)
Royalty Reductions. Caribou may reduce the royalties owed to ProMab under Section 3.2(a) during any Calendar Quarter and in any country in which Caribou is required to pay royalties to a Third Party for intellectual property covering a
Product by the amount of such Third- Party royalties; provided, however, that in no event will the royalties owed by Caribou to ProMab be reduced by more than fifty percent (50%) of the royalties set forth in Section 3.2(a). 

3.3 Calendar Quarter Reports. Within [***] calendar days after the end of each Calendar Quarter during the Term, Caribou shall deliver
to ProMab (a) a detailed report specifying in the aggregate (i) total invoiced amounts to Third Parties for Products by Caribou, its Affiliates, and any direct and indirect sublicensees thereof; and (ii) amounts deducted by
category (as defined in Section 1.6) from gross invoiced amounts to calculate Net Sales of Products; and (b) payment of royalties due. 

3.4 Method of Payment. All payments due under this Agreement shall be made in U.S. dollars and shall be made by bank wire transfer in
immediately available funds pursuant to ProMab’s wire instructions. 
 3.5 Tax Withholding. Each Party shall be responsible for
its own taxes due under this Agreement. 
 3.6 Books and Records. Caribou shall keep accurate books and records relating to the sale
of Products, as used in the calculation of Calendar Quarter reports under Section 3.3. Caribou shall permit ProMab, by 

  
 - 3 - 

 
independent qualified public accountants engaged by ProMab and reasonably acceptable to Caribou, to examine Caribou’s books and records at any reasonable time upon [***] calendar
days’ prior written notice, but not later than [***] years following the rendering of any Calendar Quarter report. The foregoing right of review may be exercised by ProMab only once during each Calendar Year and may be exercised only once with
respect to any records provided for a particular Calendar Quarter. The results of any such examination and review will be shared with Caribou within [***] business days after receipt thereof by ProMab. ProMab shall bear the cost of any such
examination and review; provided that if the inspection and audit shows an underpayment of amounts payable hereunder of more than [***] of the amount due for the applicable Calendar Quarter, then Caribou shall reimburse ProMab within [***] calendar
days of receipt of an invoice for all reasonable costs incurred in connection with such examination. Caribou shall pay to ProMab the amount of any underpayment revealed by such examination, in addition to interest owed from the date(s) such
underpayment(s) were due, within [***] calendar days of receipt of an invoice from ProMab for such underpayment and interest; and ProMab shall pay to Caribou the amount of any overpayment revealed by such examination within [***] calendar days of
receipt of an invoice from Caribou for such overpayment. 
 3.7 Interest on Late Payments. Any payments or portions thereof due
hereunder which are not paid when due shall bear interest equal to the lesser of the rate equal to prime rate effective for the date that payment was due, as published by The Wall Street Journal, U.S., Internet Edition, plus an additional
[***], or the maximum rate permitted by applicable laws, calculated on the number of calendar days such payment is delinquent. 
 ARTICLE
4 
 RESPONSIBILITIES 

4.1 Responsibility for Assigned Patent Rights and Infringement Thereof. Caribou shall have the sole responsibility, at its discretion,
for filing, prosecuting, maintaining, and enforcing the Assigned Patent Rights and for all costs and decisions relating thereto. Caribou shall have the sole right, at its discretion and costs, to institute and conduct legal action against
Third-Party infringers of the Assigned Patent Rights and/or defend any declaratory judgments with respect to the Assigned Patent Rights and to receive any recovery or settlement in connection with such legal action. 

4.2 Cooperation and Assistance. ProMab agrees and covenants that it will provide all relevant assistance to Caribou in perfecting title
to the Assigned Patent Rights (including, but not limited to, signing assignment documents) and in filing, prosecuting, and defending the Assigned Patent Rights; provided, however, that Caribou shall reimburse ProMab for its out-of-pocket costs in providing such assistance. 
 4.3
Responsibility for Products. Caribou shall have the sole control, responsibility, and authority for developing, manufacturing, filing for and obtaining all necessary regulatory approvals, and commercialization of Products; provided, however,
that nothing in this Agreement shall impose any obligation on Caribou to develop or commercialize Products and Caribou may discontinue developing or commercializing such Products at its sole discretion at any time; provided, however, that Caribou
shall provide written notice to ProMab of such discontinuation and shall remain responsible for any Calendar Quarter reports under Section 3.3 and associated royalty payments (if any) due to ProMab under Section 3.2 based on
sales (if any) that occurred prior to such discontinuation. 

  
 - 4 - 

 ARTICLE 5 

REPRESENTATIONS, WARRANTIES, AND COVENANTS 

5.1 Representations and Warranties. Each Party represents and warrants to the other that: 

(a) it is duly organized and validly existing under the applicable laws of the jurisdiction of its incorporation and has full corporate power
and authority to enter into this Agreement and to carry out the provisions hereof; (b) it is duly authorized to execute and deliver this Agreement and to perform its obligations hereunder, and the person executing this Agreement on its behalf
has been duly authorized to do so by all requisite corporate action; (c) this Agreement is legally binding upon it and enforceable in accordance with its terms, and the execution, delivery, and performance of this Agreement by it does
not conflict with any agreement, instrument, or understanding, oral or written, to which it is a party or by which it may be bound, nor violate any applicable laws; and (d) it is not aware of any action, suit, or inquiry or investigation
instituted by any entity which questions or threatens the validity of this Agreement. 
 5.2 Additional ProMab Representations and
Warranties. [***] 
 5.3 Limitations. EXCEPT AS PROVIDED IN THIS ARTICLE 5, NEITHER PARTY MAKES ANY REPRESENTATIONS, WARRANTIES,
OR CONDITIONS (EXPRESS, IMPLIED, STATUTORY, OR OTHERWISE) WITH RESPECT TO THE SUBJECT MATTER HEREOF, AND EACH PARTY SPECIFICALLY DISCLAIMS ANY AND ALL IMPLIED WARRANTIES OR CONDITIONS OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE. 

[***] 
 ARTICLE 6 

CONFIDENTIALITY 
 6.1
Definition. “Confidential Information” means all business and research information of a Party or its Affiliates (including, but not limited to, information about research, development, preclinical and clinical studies, regulatory
affairs, intellectual property, operations, marketing, business plans, financial statements, biological materials, software, product specifications, data, know- how, and the like, whether tangible or intangible, and including all copies, abstracts,
summaries, analyses, and other derivatives thereof) furnished by one Party (the “Disclosing Party”) to the other Party or its Affiliates (the “Receiving Party”) or to the Receiving Party’s directors, officers, employees or
representatives, including, but not limited to, attorneys, accountants, consultants, and financial advisors who are under obligations of confidentiality at least as stringent as those set forth herein (collectively, “Representatives”)
that: (a) is disclosed in writing or other tangible form and marked “Confidential,” “Proprietary,” or in some other manner to indicate its confidential nature; (b) is initially disclosed in oral or other intangible form
and subsequently confirmed in writing within [***] calendar days after its initial disclosure; or (c) the nature of the information and the manner of disclosure are such that a reasonable person would understand it to be confidential. Calendar
Quarter reports under Section 3.3 shall be Caribou Confidential Information. 

  
 - 5 - 

 6.2 Exceptions. Confidential Information will not include any information that the
Receiving Party can document by competent evidence: (a) is or becomes generally known to the public without violation of this Agreement by the Receiving Party or its Representatives; (b) is in the rightful possession of the
Receiving Party without confidentiality obligations at the time of disclosure by the Disclosing Party to the Receiving Party; (c) is obtained by the Receiving Party from a Third Party without an accompanying duty of confidentiality and
without a breach of such Third Party’s obligations of confidentiality; or (d) is independently developed by the Receiving Party without use of the Disclosing Party’s Confidential Information. 

6.3 Non-Disclosure and Non-Use Obligations. The
Receiving Party and its Representatives shall not: (a) disclose any Confidential Information of the Disclosing Party to Third Parties; (b) use any Confidential Information of the Disclosing Party except as is necessary to perform its
obligations under this Agreement. The Receiving Party shall immediately cease all use of the any Confidential Information of the Disclosing Party upon termination or expiration of this Agreement, and the obligations of confidentiality shall remain
in place for a period of [***] years from expiration or termination of this Agreement. 
 6.4 Maintenance of Confidentiality. The
Receiving Party and its Representatives shall: (a) take reasonable measures to protect the secrecy of, and avoid disclosure and unauthorized use of, the Confidential Information of the Disclosing Party; without limiting the foregoing, the
Receiving Party shall take at least those measures that it employs to protect its own confidential information of a similar nature; and (b) reproduce the Disclosing Party’s confidential rights notices on any such authorized copies
in the same manner in which such notices were set forth in or on the original. The Receiving Party shall promptly notify the Disclosing Party of any unauthorized use or disclosure, or suspected unauthorized use or disclosure, of the Disclosing
Party’s Confidential Information of which the Receiving Party or its Representatives become aware. Each Party will be responsible for any breach of this Agreement by its Representatives. 

6.5 Export Restrictions. The Receiving Party and its Representatives agree not to export or
re-export any Confidential Information or product thereof in violation of U.S. or other export control laws or regulations. 

6.6 Compelled Disclosure. In the event the Receiving Party is legally required to disclose Confidential Information of the Disclosing
Party by judicial or governmental order, or in a judicial or governmental proceeding (“Compelled Disclosure”), the Receiving Party shall: (a) give the Disclosing Party prompt notice of such Compelled Disclosure prior to
disclosure; (b) cooperate with the Disclosing Party in the event that it elects to contest such Compelled Disclosure or seek a protective order with respect thereto; and (c) in any event only disclose the exact Confidential
Information or portion thereof specifically requested by the Compelled Disclosure. 
 6.7 Remedies. The Receiving Party agrees that
any violation of this Article 6 may cause irreparable injury to the Disclosing Party, entitling the Disclosing Party to seek injunctive relief in addition to all other legal remedies. 

6.8 Confidential Terms. Each Party shall treat the terms of this Agreement as the Confidential Information of the other Party.
Notwithstanding anything to the contrary, however, each Party may disclose the terms of this Agreement to its directors, officers, employees, Representatives, and actual or potential investors, acquisition partners, lenders, or collaboration
partners subject to the restrictions set forth in this Article 6. 

  
 - 6 - 

 6.9 Press Releases. In the event a Party wishes to issue a press release related to
this Agreement during the Term, such Party will provide a draft to the other Party at least [***] business days prior to such planned release for review and approval; alternatively, the Parties may decide to issue a joint press release related to
this Agreement and, in such event, will exchange drafts prior to issuance of a joint press release. Both Parties shall have the right to post a brief description of the subject of this Agreement (including, but not limited to, the other Party’s
name and logo, title and date of the Agreement, and scope of the assignments) on its website; provided, however, that such Party shall provide a written copy of the proposed website language to the other Party for review and approval prior to
posting. 
 ARTICLE 7 

INDEMNIFICATION 
 7.1
Indemnification by ProMab. ProMab hereby agrees to indemnify, hold harmless, and defend (collectively, “Indemnify”) Caribou and its Affiliates, and their directors, officers, and employees (the “Caribou Indemnitees”) from
and against any losses, damages, costs, fees, and expenses (including reasonable legal expenses and attorneys’ fees) (collectively, “Losses”) resulting from any claims, suits, actions, or demands brought by a Third Party (each, a
“Third-Party Claim”) arising out of [***]. ProMab’s obligation to Indemnify Caribou Indemnitees pursuant to this Section shall not apply to the extent that any such Losses arise from the negligence or intentional misconduct of any
Caribou Indemnitee or arise from any material breach by Caribou of this Agreement. 
 7.2 Indemnification by Caribou. Caribou hereby
agrees to Indemnify ProMab and its directors, officers, and employees (the “ProMab Indemnitees”) from and against any and all Losses resulting from Third-Party Claims arising out of [***]. Caribou’s obligation to Indemnify the ProMab
Indemnitees pursuant to this Section 7.2 shall not apply to the extent that any such Losses arise from the negligence or intentional misconduct of any ProMab Indemnitee or arise from any material breach by ProMab of this Agreement. 

7.3 Indemnification Procedure. To be eligible to be Indemnified hereunder, the indemnified Party shall provide the indemnifying Party
with prompt notice of the Third-Party Claim, suit, action, or demand giving rise to the indemnification obligations pursuant to Section 7.1 or 7.2, as applicable, and the exclusive ability to defend (with the reasonable cooperation of
the indemnified Party) or settle any such claim; provided, however, that the indemnifying Party shall not enter into any settlement that admits fault, wrongdoing, or damages without the indemnified Party’s written consent, such consent not to
be unreasonably withheld or delayed. The indemnified Party shall have the right to participate, at its own expense and with counsel of its choice, in the defense of any claim or suit that has been assumed by the indemnifying Party. 

ARTICLE 8 
 TERM AND
TERMINATION 
 8.1 Term. Unless terminated earlier pursuant to Section 8.2(a) or Section 8.2(b), this Agreement
shall remain in full force and effect during the Term. 

  
 - 7 - 

 8.2 Termination for Cause. 

(a) Material Breach. Either Party, at its sole discretion, may terminate this Agreement for a material breach by the other Party upon
[***] prior written notice if the other Party does not cure the breach within such [***] period. (i) In the event of termination under this Section 8.2(a) by ProMab, the covenant not to sue set forth in Section 2.4 shall
terminate upon the end of the [***] cure period. (ii) In the event of termination under this Section 8.2(a) by Caribou, the covenant not to sue set forth in Section 2.4 shall remain in full force and effect. 

(b) Bankruptcy. Either Party, at its sole discretion, may terminate this Agreement by written notice immediately if the other Party
makes an assignment for the benefit of creditors or files for bankruptcy or liquidation, or any decree or order for relief by a court of competent jurisdiction is issued against the other Party under any applicable bankruptcy, dissolution, or
liquidation laws. (i) In the event of termination under this Section 8.2(b) by ProMab, the covenant not to sue set forth in Section 2.4 shall terminate on the date it provides written notice to Caribou of such
termination. (ii) In the event of termination under this Section 8.2(b) by Caribou, the covenant not to sue set forth in Section 2.4 shall remain in full force and effect. 

8.3 Effect of Termination or Expiration. Solely upon termination of this Agreement by ProMab under Section 8.2(a) or
Section 8.2(b), Caribou shall (a) immediately cease any and all manufacture, sale, offer for sale, use, import, and/or export of Products, provided, however, that Caribou, its Affiliates, and any direct and indirect sublicensees thereof
may, for a period not to exceed [***] from the date of termination, sell any remaining existing inventory of Products, with Caribou remaining responsible for any Calendar Quarter reports under Section 3.3 and associated royalty payments
(if any) due to ProMab under Section 3.2 based on such sales; and (b) within [***] of such termination, notify its Affiliates and any direct and indirect sublicensees thereof of the termination of this Agreement. 

8.4 Survival. Sections 2.1, 2.2, 2.3, 2.4 (only in the event of termination by Caribou under Section 8.2(a) or
Section 8.2(b)), 3.4, 3.5, 3.6, 3.7, 4.3, 5.3, 5.4, 8.2, 8.3, and 8.4, and Articles 1, 6, 7, and 9 shall survive the expiration and any termination of this Agreement. Except as otherwise provided in this Article 8, all other provisions of this
Agreement shall terminate upon the expiration or termination of this Agreement. 
 ARTICLE 9 

GENERAL 
 9.1 Governing
Law. This Agreement shall be governed by, and construed and interpreted in accordance with, the laws of the State of California without reference to principles of conflicts of law. 

9.2 Assignment of this Agreement. This Agreement shall be assignable by either Party only with the prior written consent of the other
Party and any assignment in violation of this Section 9.2 shall be null and void; provided, however, that either Party may assign this Agreement without the other Party’s consent to an Affiliate or in connection with the sale or transfer
of all or substantially all of the Party’s assets or business, provided such Affiliate or successor-in-interest agrees to be bound by all terms and conditions of
this Agreement. Furthermore, the covenant not to sue set forth in Section shall be transferable to and for the benefit of an assignee of this Agreement by Caribou upon assignment of this Agreement as permitted under this Section 9.2 and shall
be binding with respect to any assignee of ProMab upon assignment of this Agreement by ProMab permitted under this Section 9.2. 

  
 - 8 - 

 9.3 Independent Contractors. The Parties agree that the relationship of ProMab and
Caribou established by this Agreement is that of independent contractors. Furthermore, the Parties agree that this Agreement does not, is not intended to, and shall not be construed to, establish an employment, agency, or any other relationship.
Except as explicitly set forth herein, neither Party shall have any right, power, or authority, nor shall they represent themselves as having any authority to assume, create, or incur any expense, liability, or obligation, express or implied, on
behalf of the other Party, or otherwise act as an agent for the other Party for any purpose. Each Party shall bear its own costs and expenses incurred in the negotiation and preparation of this Agreement. 

9.4 Notices. Any notice, request, delivery, approval, or consent required or permitted to be given under this Agreement shall be in
writing and shall be deemed to have been sufficiently given if delivered in person, transmitted by facsimile or electronic mail (receipt verified) or by express courier service (signature required), or five (5) business days after it was
sent by registered letter, return receipt requested (or its equivalent), to the Party to which it is directed at its address shown below or such other address as provided in writing by one Party to the other Party. 

 

			
	If to ProMab:	  	[***]
		  	[***]
		
	If to Caribou:	  	[***]
		  	[***]

 9.5 Compliance with Applicable Laws. Each Party shall comply with all applicable laws in connection
with its activities pursuant to this Agreement. 
 9.6 Force Majeure. Except for nonpayment of monies, neither Party shall be held
liable to the other Party nor be deemed to have defaulted under or breached this Agreement for failure or delay in performing any obligation under this Agreement to the extent such failure or delay is caused by or results from causes beyond the
reasonable control of the affected Party, potentially including, but not limited to, embargoes, war, acts of war (whether war be declared or not), acts of terrorism, insurrections, riots, civil commotions, strikes, lockouts or other labor
disturbances, fire, floods, or other acts of God, or acts, omissions or delays in acting by any governmental authority or the other Party. The affected Party shall notify the other Party of such force majeure circumstances as soon as reasonably
practical, shall promptly undertake all reasonable efforts necessary to cure and/or mitigate such force majeure circumstances, and shall provide updates to the other Party on a regular basis of the force majeure circumstances and efforts to cure
and/or mitigate. 
 9.7 No Waiver. A waiver, express or implied, by either ProMab or Caribou, of any right under this Agreement or of
any failure to perform or breach hereof by the other Party shall not constitute or be deemed to be a waiver of any other right hereunder or of any other failure to perform or breach hereof by such other Party, whether of a similar or dissimilar
nature thereto. 
 9.8 Severability. If any provision of this Agreement shall be found by a court to be void, invalid, or
unenforceable, the same shall be reformed to comply with applicable laws or stricken if not so conformable, so as not to affect the validity or enforceability of the remainder of this Agreement, and the remainder of this Agreement shall remain in
full force and effect. 

  
 - 9 - 

 9.9 Interpretation. The captions and headings to this Agreement are for convenience
only and are to be of no force or effect in construing or interpreting any of the provisions of this Agreement. Unless specified to the contrary, references to Articles, Sections, or Exhibit mean the particular Articles, Sections, and Exhibit
A and Exhibit B of this Agreement. 
 9.10 Entire Agreement; Amendments. This Agreement constitutes the entire
understanding and agreement between the Parties with respect to the subject matter hereof and supersedes any and all prior and contemporaneous negotiations, representations, agreements, term sheets, and understandings, written or oral, that the
Parties may have reached with respect to the subject matter hereof, including but not limited to [***]; all of which are hereby superseded in their entireties and completely replaced by this Agreement. Any and all Confidential Information disclosed
under such agreements shall be governed by this Agreement. Any and all amendments and modifications to this Agreement must be in writing and signed by duly authorized representatives of each of the Parties. 

9.11 Counterparts. This Agreement may be executed in counterparts, including facsimile, scanned PDF documents, or electronic signature.
Each such counterpart shall be deemed an original, and both of which together shall constitute one and the same executed Agreement. 

(Remainder of page left intentionally blank; signature page follows) 

  
 - 10 - 

 IN WITNESS WHEREOF, the Parties have executed this Sale and Assignment Agreement by
their duly authorized representatives as of the Effective Date set forth above. 
  

									
	ProMab Biotechnologies, Inc.	 		 	Caribou Biosciences, Inc.
					
	By:	 	 /s/ John Wu
	 		 	By:	 	 /s/ Rachel E. Haurwitz

	Name:	 	John Wu, Ph.D.	 		 	Name:	 	Rachel E. Haurwitz, Ph.D.
	Title:	 	Chief Executive Officer	 		 	Title:	 	President & Chief Executive Officer

  
 - 11 - 

 Exhibit A 

Assigned Patent Rights 
  

							
	 Humanized BCMA CAR-T Cells

	 Country
	  	 Patent application number
	  	 Filing date
	  	 Status

	US	  	62/793,274	  	01/16/2019	  	Expired
	WO	  	PCT/US2020/013662	  	01/15/2020	  	Pending

 Exhibit B 

Sequence of PMC306 
 [***]

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00330-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00330-of-00352.parquet"}]]