Document:

EX-10.14

 Exhibit 10.14 

CONFIDENTIAL TREATMENT REQUESTED 

ASSIGNMENT AND LICENSE AGREEMENT 

This ASSIGNMENT AND LICENSE AGREEMENT (this “Agreement”) is entered into as of May 9, 2016 (the “Effective
Date”), by and between Vertex Pharmaceuticals Incorporated, with an address at 50 Northern Avenue, Boston, Massachusetts 02210 (“Vertex”) and Spero Trinem, Inc., with an address at 675 Massachusetts Avenue, 14th Floor, Cambridge, Massachusetts 02139 (“Spero”) and solely for the purposes of Section 13.15, Spero Therapeutics, LLC, with an address at 675 Massachusetts Avenue, 14th Floor, Cambridge, Massachusetts 02139 (“Parent”). Vertex and Spero each may be referred to herein individually as a “Party” or collectively as the
“Parties.” 
 WHEREAS, Vertex owns rights to the proprietary compound identified as
VXc-100/VXc486; and 
 WHEREAS, Spero desires to obtain the rights to develop and
commercialize VXc-100/VXc486 and Vertex desires to grant such rights, all in accordance with the terms of this Agreement; 

NOW, THEREFORE, in consideration of the covenants and obligations set forth herein, and other good and valuable consideration, the
Parties agree as follows: 
 ARTICLE 1. 

DEFINITIONS 
 For purposes
of this Agreement, the following capitalized terms will have the meaning set forth below: 
 1.1. “Affiliate” means, as of
any point in time and for so long as such relationship continues to exist with respect to any Person, any other Person that controls, is controlled by or is under common control with such Person. A Person will be regarded as in control of another
Person if it (a) owns or controls more than 50% of the equity securities of the subject Person entitled to vote in the election of directors (or, in the case of a Person that is not a corporation, for the election of the corresponding managing
authority); provided, however, that the term “Affiliate” will not include subsidiaries or other entities in which a Person owns a majority of the ordinary voting power necessary to elect a majority of the board of directors
or other governing board, but is restricted from electing such majority by contract or otherwise, until such time as such restrictions are no longer in effect, or (b) possesses, directly or indirectly, the power to direct or cause the direction
of the management or policies of any such Person (whether through ownership of securities or other ownership interests, by contract or otherwise). 

1.2. “Agreement” has the meaning set forth in the preamble. 

1.3. “Anti-Corruption Laws” has the meaning set forth in Section 5.2. 

1.4. “Approval Application” means new drug application that is submitted to the FDA pursuant to 21 C.F.R. 314.3 or similar
application or submission for a Product filed with a Regulatory Authority in a country or group of countries to obtain Marketing Approval for a pharmaceutical product in that country or group of countries. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.5. “Additional Compound” means any compound Covered by the claimed genus
in any issued Assigned Patent as the issued Assigned Patents exist as of the Effective Date, or a compound that would be Covered by a disclosed genus in any pending Assigned Patent as of the Effective Date should such disclosed genus issue to grant,
in each case including [***], other than the Assigned Compound. 
 1.6. “Assigned Compound” means each of (a) VXc-486 and (b) VXc-100 (the prodrug of VXc-486), including [***]. 

1.7. “Assigned Know-How” means the information identified in Exhibit B to the
extent Controlled by Vertex as of the Effective Date and to the extent solely and specifically related to the Assigned Compounds or Additional Compounds, but excluding all information related to Vertex’s general drug design, delivery,
formulation and manufacturing technologies and know-how applicable to or related to Vertex’s business in general and other programs. 

1.8. “Assigned Patents” means the Patents listed in Exhibit A, including any
re-examination, re-issue, continuation, or division thereof (to the extent that each claimed invention in such application is Covered by one or more claims in the
patents listed in Exhibit A) and any foreign counterparts filed or issued in the Territory. 
 1.9. “Associated
Persons” has the meaning set forth in Section 5.2. 
 1.10. “Business Day” means a Monday, Tuesday, Wednesday,
Thursday or Friday that is not a day on which banking institutions in Boston, Massachusetts are authorized or obligated to close. 
 1.11.
“Calendar Quarter” means the respective periods of three consecutive calendar months ending on March 31, June 30, September 30 or December 31, during the Term, or the applicable part thereof during the first or
last calendar quarter of the Term. 
 1.12. “Calendar Year” means any calendar year ending on December 31, or the
applicable part thereof during the first or last year of the Term. 
 1.13. “Change of Control” means, with respect to a
Party, (a) a merger or consolidation of such Party with a Third Party that results in the voting securities of such Party outstanding immediately prior thereto, or any securities into which such voting securities have been converted or
exchanged, ceasing to represent more than 50% of the combined voting power of the surviving entity or the parent of the surviving entity immediately after such merger or consolidation, or (b) a transaction or series of related transactions in
which a Third Party, together with its Affiliates, becomes the beneficial owner of more than 50% of the combined voting power of the outstanding securities of such Party, or (c) the sale or other transfer to a Third Party of all or
substantially all of such Party’s business to which the subject matter of this Agreement relates. For the avoidance of doubt, in no event shall a bona fide equity or debt financing of a Party, including a financing in which greater than 50% of
a Party’s outstanding equity securities are acquired by a Third Party, be deemed a “Change in Control.” 
 1.14.
“Claims” has the meaning set forth in Section 11.1. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.15. “Combination Product” means any product, process or service which
incorporates one or more therapeutically active ingredients, other than an Assigned Compound or Additional Compound, in combination or co-formulation with an Assigned Compound or Additional Compound. 

1.16. “Commercialize” or “Commercialization” means (a) to market, promote, distribute, offer for sale,
sell, have sold, import, export or otherwise commercialize a Product and (b) to conduct activities other than Research, Development and Manufacturing, in preparation for the foregoing activities, including obtaining pricing approval, and to
conduct post-Marketing Approval studies (including clinical trials). 
 1.17. “Confidential Information” means all non-public, confidential or proprietary information, data or know-how, provided by one Party (the “Disclosing Party”) to the other Party (the
“Receiving Party”) in any form pursuant to this Agreement, including information relating to the Disclosing Party’s existing or proposed research, development, patent applications, business or products. Vertex’s
Confidential Information will include the Licensed Know-How. The Assigned Know-How will be deemed to be Spero’s Confidential information. The terms of this
Agreement will be deemed to be each Party’s Confidential Information. Confidential Information will not include any information or materials that the Receiving Party can document with competent written proof: 

(a) were already known to the Receiving Party (other than under an obligation of confidentiality) at the time of disclosure by
or on behalf of the Disclosing Party; 
 (b) were generally available to the public or otherwise part of the public domain at
the time of its disclosure to the Receiving Party; 
 (c) became generally available to the public or otherwise part of the
public domain after its disclosure to the Receiving Party, other than through any act or omission of the Receiving Party in breach of its obligations under this Agreement; 

(d) were disclosed to the Receiving Party, other than under an obligation of confidentiality, by a Third Party who had no
obligation to the Disclosing Party not to disclose such information to the Receiving Party or others; or 
 (e) were
independently discovered or developed by or on behalf of the Receiving Party without the use of the Confidential Information belonging to the Disclosing Party. 

Confidential Information disclosed to the Receiving Party hereunder will not be deemed to fall within the foregoing exceptions
merely because broader or related information falls within such exceptions, nor will combinations of elements or principles be considered to fall within the foregoing exceptions merely because individual elements of such combinations fall within
such exceptions. 
 1.18. “Controlled” means, with respect to any know-how, Patent
or other intellectual property right, possession of the right, whether directly or indirectly, and whether by ownership, license or otherwise, to assign, or grant a license, sublicense or other right to or under, such 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 CONFIDENTIAL TREATMENT REQUESTED 

 

 
know-how, Patent, or right as provided for herein without violating the terms of any agreement or other arrangements with any Third Party; provided
that if the assignment or license of such know-how, Patent or other intellectual property right would trigger a royalty or other payment to a Third Party or would require compliance with any provision
of any license between Vertex and a Third Party, Vertex will so notify Spero and such know-how, Patent or other intellectual property right will only be deemed Controlled if, following receipt of such notice,
Spero agrees in writing to reimburse Vertex for all such payments to such Third Party and comply with any such provision. 
 1.19.
“Cover,” “Covering,” “Covers” or “Covered” means, as to a compound or product and Patent, that, in the absence of a license granted under, or ownership of, such Patent, the making,
using, keeping, selling, offering for sale or importation of such compound or product would infringe such Patent or, as to a pending claim included in such Patent, the making, using, selling, offering for sale or importation of such compound or
product would infringe such Patent if such pending claim were to issue in an issued patent without modification. 
 1.20.
“Development” means, with respect to a Product, all clinical and non-clinical research and development activities conducted after filing of an IND for such Product, including toxicology,
pharmacology test method development and stability testing, process development, formulation development, delivery system development, quality assurance and quality control development, statistical analysis, clinical trials (other than
post-Marketing Approval clinical trials), regulatory affairs, pharmacovigilance, clinical trial regulatory activities and obtaining and maintaining regulatory approval. 

1.21. “Disclosing Party” has the meaning set forth in the definition of Confidential Information. 

1.22. “Effective Date” has the meaning set forth in the preamble. 

1.23. “EMA” means the European Medicines Agency and any successor entity thereto. 

1.24. “European Commission” means the European Commission or any successor entity that is responsible for granting marketing
approvals authorizing the sale of pharmaceuticals in the European Union. 
 1.25. “European Union” or “EU”
means all countries or territories that are officially part of the European Union. 
 1.26. “FDA” means the United States
Food and Drug Administration and any successor entity thereto. 
 1.27. “Field” means the diagnosis, treatment or prevention
of bacterial infections, excluding the [***]. 
 1.28. “First Commercial Sale” means, with respect to a particular Product
in a particular country in the Territory, the first commercial sale of such Product to a Third Party for end use or consumption in such country in an arm’s length transaction by Spero or any other Seller after the receipt of Marketing Approval
in such country. Sales for test marketing, sampling and promotional uses, clinical trial purposes or compassionate or similar use will not constitute a First Commercial Sale. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.29. “IND” means any Investigational New Drug application, filed with the
United States Food and Drug Administration pursuant to Part 312 of Title 21 of the U.S. Code of Federal Regulations, including any supplements or amendments thereto. References herein to IND will include, to the extent applicable, any comparable
filings outside the United States. 
 1.30. [***]. 

1.31. “Licensee” has the meaning set forth in Section 2.5(a). 

1.32. “Licensed Know-How” means all information other than Assigned Know-How that (a) was Controlled by Vertex as of the Effective Date and remains under the Control of Vertex during the Term, (b) was used by Vertex in its Research, Development or Manufacturing of the
Assigned Compounds or Additional Compounds and (c) is necessary for the Research, Development, use, Manufacturing or Commercialization of the Assigned Compound or Additional Compounds. Licensed Know-How
does not include Vertex’s general drug design or delivery technology, formulation and manufacturing technology, whether in hardware or software form, tangible or intangible, or information relating to any compounds or active ingredients other
than the Assigned Compound or Additional Compounds and formulation and manufacturing technology not applied to an Assigned Compound or Product containing an Assigned Compound by or on behalf of Vertex. 

1.33. “Manufacture” or “Manufactured” or “Manufacturing” means activities directed to
making, having made, producing, manufacturing, processing filling, finishing, packaging, labeling, quality control testing and quality assurance release, shipping or storage of a Product. 

1.34. “Marketing Approval” means, with respect to a Product in a particular jurisdiction, the receipt of all approvals,
licenses, registrations or authorizations necessary for the Commercialization of such Product in such jurisdiction, including, with respect to the United States, approval of an Approval Application for such Product by the FDA, with respect to the
European Union, approval of an Approval Application for such Product by the European Commission, and with respect to Japan, approval of an Approval Application for such Product by the Ministry of Health, Labor and Welfare or any successor government
agency responsible for approving the sale of pharmaceuticals in Japan. For clarity, Marketing Approval does not include reimbursement authorization or pricing approval determinations. 

1.35. “Materials” means raw materials, pharmaceutical ingredients, intermediates and drug products identified in Exhibit
C. 
 1.36. “Milestone Event” has the meaning set forth in Section 4.2. 

1.37. “Milestone Payment” has the meaning set forth in Section 4.2. 

1.38. “Monetization Transaction” has the meaning set forth in Section 4.6. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.39. “Net Sales” means the gross amount billed or invoiced by Spero, its
Related Parties and their Licensees, assignees, or any other Third Party to which Spero grants rights with respect to the Manufacturing and/or Commercialization of a Product (including by assignment of the Assigned Patents or Assigned Know-How) (collectively referred to as the “Seller”) on sales of a Product to a Third Party, less Permitted Deductions determined under United States generally accepted accounting principles.
“Permitted Deductions” means the following: 
 (a) customary transportation charges relating to such
Product, including handling charges, outbound freight, shipment and insurance premiums relating thereto; 
 (b) sales taxes,
excise taxes, use taxes, tariffs and duties paid by and not refunded to the seller and directly related to sale of such Product, and any other equivalent governmental charges imposed upon the importation, use or sale of such Product, but excluding
income and similar taxes; 
 (c) government-mandated deductions and other rebates (notably but not limited to those in
respect of any state or federal Medicare, Medicaid or similar programs), clawbacks or other forms of payment to any governmental authority or agency and payments or accruals made with respect to any national or local health insurance program,
including government fees levied as a result of health care reform policies such as the branded prescription drug fee of the Affordable Care Act; 

(d) customary trade, quantity and cash discounts, allowances and credits allowed or paid in the form of deductions actually
allowed or fees actually paid with respect to sales of such Product (to the extent not already reflected in the amount invoiced); 

(e) allowances or credits to customers on account of retrospective price reductions, rejections or returns of Product,
including billing errors; and 
 (f) customary rebates, charge backs and discounts (or equivalent thereof) actually granted
for such Product including those customarily granted to managed care entities or organizations, pharmacy benefit managers (or equivalent thereof), federal, state/provincial, local or other governments or their agencies or purchasers, reimbursers or
trade customers. 
 A Permitted Deduction set forth in Section 1.39(a)-1.39(f) above may be deducted only once,
regardless of the number of the preceding categories that describe such amount. A sale between or among Spero, or its Related Parties will be excluded from the computation of Net Sales if such sale is not intended for end use, but Net Sales will
include the subsequent final sales to Third Parties by Spero or any such Related Parties. A Product will not be deemed to be sold if the Product is provided free of charge to a Third Party in reasonable quantities as a sample consistent with
industry standard promotional and sample practices. For clarity, Net Sales includes [***]. 
 In the case of any sale that is not invoiced, Net Sales will
be calculated at the time of transfer of title of the Product based on the gross selling price. If a sale, transfer or other disposition with respect to a Product involves consideration other than cash or is not at arm’s length, then the Net
Sales from such sale, transfer or other disposition will be calculated based on the fair market value of the Product as reasonably determined by the Parties. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 CONFIDENTIAL TREATMENT REQUESTED 

 

 For all purposes of this Agreement, if a Product is a Combination Product, then for purposes of determining
Net Sales for such Combination Product, the actual Net Sales for such Combination Product (determined as provided above) will be [***]. 

1.40. “Party” or “Parties” has the meaning set forth in the preamble. 

1.41. “Patents” means patents existing upon the Effective Date and future patents and patent applications including without
limitation provisional applications, continuation applications, continuations-in-part, divisional applications, Patent Cooperation Treaty applications, invention
patents, utility model patents, industrial design patents, reexaminations, reissues, registrations, confirmations, revalidations, certificates of addition, utility models and petty patents, including extensions or restorations of terms thereof,
pediatric exclusivity extension of a patent, supplementary protection certificates or any other such right. 
 1.42. “Permitted
Deductions” has the meaning set forth in the definition of Net Sales. 
 1.43. “Person” means any natural person,
corporation, general partnership, limited partnership, limited liability company, joint venture, joint-stock company, proprietorship or other business organization or legal entity. 

1.44. [***]. 
 1.45. [***]. 

1.46. “Product” means any preparation, substance or formulation comprised, in whole or in part, of an Assigned Compound or an
Additional Compound. For the avoidance of doubt, Product includes any Combination Product or Single Agent Product. 
 1.47. “Progress
Report” has the meaning set forth in Section 7.1. 
 1.48. “Receiving Party” has the meaning set forth in the
definition of Confidential Information. 
 1.49. “Regulatory Authority” means, with respect to a country in the Territory,
any national (e.g., the FDA), supra-national (e.g., the European Commission, the Council of the European Union, or the EMA), regional, state or local regulatory agency, department, bureau, commission, council or other governmental authority involved
in the granting of Marketing Approvals or price approvals for pharmaceutical products in such country or countries. 
 1.50.
“Regulatory Exclusivity” means, upon Marketing Approval, the period during which a drug product is granted exclusive marketing rights by the FDA, European Commission, Ministry of Health, Labor and Welfare or the applicable
Regulatory Authority with respect to any country in the Territory or any successor Regulatory Authority. 
 1.51. “Related
Party” means each of Spero’s Affiliates and permitted Sublicensees. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.52. “Research” means conducting research activities to advance the
Assigned Compounds, Additional Compounds and Products, including pre-clinical studies and optimization, but specifically excluding Development and Commercialization. 

1.53. “Revenue Buyer” has the meaning set forth in Section 4.6. 

1.54. “Royalty Term” means, with respect to a Product in a country, the period commencing on the first sale generating Net
Sales of such Product in such country and ending on the later of (a) [***] after the First Commercial Sale of such Product in such country or (b) the date of expiration of the last to expire Assigned Patent. 

1.55. “Seller” has the meaning set forth in the definition of Net Sales. 

1.56. “Single Agent Product” means any Product that is not a Combination Product. For clarity, a Product containing or
comprised of one or more Assigned Compounds and/or one or more Additional Compounds and no other therapeutically active ingredients will be deemed to be a Single Agent Product. 

1.57. “Storage Facility” has the meaning set forth in Section 2.6. 

1.58. “Sublicensee” means an Affiliate or Third Party, to whom Spero (or Spero’s Sublicensee or Affiliate) assigns,
licenses or sublicenses any of the rights granted to Spero hereunder during the Term. 
 1.59. “Term” has the meaning set
forth in Section 8.1. 
 1.60. “Territory” means worldwide. 

1.61. “Third Party” means any Person other than Vertex, Spero or their respective Affiliates. 

1.62. “Third Party Auditor” has the meaning set forth in Section 4.5. 

1.63. “United States” or “U.S.” means the United States of America and all of its districts, territories and
possessions. 
 1.64. “Spero” has the meaning set forth in the preamble. 

1.65. “Spero Indemnitees” has the meaning set forth in Section 11.2. 1.66. 

1.66. “Vertex” has the meaning set forth in the preamble. 

1.67. “Vertex Indemnitees” has the meaning set forth in Section 11.1. 

1.68. “Withheld Taxes” has the meaning set forth in Section 4.4(c)(ii). 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 ARTICLE 2. 

LICENSE; ASSIGNMENTS 
 2.1.
Assignment of Rights. Subject to the terms and conditions of this Agreement, Vertex hereby assigns to Spero, and Spero hereby accepts, all of Vertex’s right, title and interest in the Assigned Patents and Assigned Know-How, free and clear of all liens, claims, encumbrances, security interests, license, options, charges or restrictions of any kind or nature (collectively, “Liens”). If requested by Spero,
Vertex will reasonably cooperate with Spero to take all actions, including but not limited to the execution of patent assignments, customary and suitable written instruments or other documents reasonably requested by Spero to effect the assignment
of rights described in this Section 2.1. 
 2.2. License to Vertex. Notwithstanding the foregoing, effective upon the assignment
of Assigned Patents and Assigned Know-how pursuant to Section 2.1, Spero will, and hereby does, grant to Vertex a perpetual, irrevocable, exclusive, royalty-free, fully
paid-up, worldwide, sublicensable (through multiple tiers) license under any such Assigned Patents and Assigned Know-How to research, develop, manufacture, have
manufactured, use, keep, sell offer for sale, import, export and commercialize any Assigned Compound or Additional Compound for any use outside of the Field, including, without limitation, the use of the Assigned Compound and Additional Compounds in
any compound screening libraries and Vertex internal toxicity and DMPK databases that Vertex maintains. 
 2.3. Licensed Know-How. Subject to the terms and conditions of this Agreement, Vertex hereby grants to Spero a non-exclusive, royalty-bearing, revocable (as set forth in
Section 8.2), sublicenseable (solely as set forth in Section 2.5), nontransferable (except to the extent this Agreement is assigned by Spero in accordance with Section 13.2) license under the Licensed
Know-How to Research, Develop, Manufacture, have Manufactured, use, keep, sell, offer for sale, import, export and Commercialize the Assigned Compounds, Additional Compounds and Products containing the
Assigned Compounds and/or Additional Compounds, for use in the Field in the Territory during the Term. Notwithstanding the license granted to Spero under this Section 2.3, Vertex will not be obligated to provide Spero with access to, or copies
or physical embodiments of, any Licensed Know-How except as set forth herein. 
 2.4. Certain
Restriction. Spero (or its Affiliates or Licensees) will not use the Assigned Compounds, Additional Compounds, Licensed Know-How, Assigned Know-How, Assigned
Patents, or any other materials or information provided hereunder for purposes of researching, developing, commercializing or manufacturing products outside of the Field or relating to any other activities outside of the Field. 

2.5. Licensing; Sublicensing. 

(a) Spero will have the right to assign or grant licenses or sublicenses (through multiple tiers) under the rights assigned to
Spero pursuant to Section 2.1 to its Affiliates and any Third Party (each, a “Licensee” and collectively, the “Licensees”), without the prior written consent of Vertex; provided that (i) the
terms of any assignment, license or sublicense by Spero or a Licensee will be in a written agreement and consistent with the terms of this Agreement, (ii) Spero’s grant of any assignment, license or 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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sublicense will not relieve Spero from any of its obligations under this Agreement, (iii) Spero will remain responsible for its Licensees’ performance under this Agreement including
payment of royalties for Products by such Licensee and (iv) Spero will notify Vertex of the identity of any Licensee and the territory in which it has granted such assignment, license or sublicense, after entering into any such assignment,
license or sublicense. Notwithstanding the foregoing, before entering into any agreement with a Third Party in accordance with this Section 2.5(a) to Commercialize a Product, or any agreement to effectuate a Change of Control, Spero will notify
Vertex of its intent to license, sublicense or assign rights as provided in this Section 2.5(a) or undergo such Change of Control, which notice will specify the [***] or the [***] the Change of Control Spero intends to consummate, as
applicable, and Vertex may elect in writing within [***] after receipt of such notice to enter into good faith negotiations with Spero with respect to such transaction. If Vertex so elects, the Parties will in good faith negotiate the terms of such
transaction for a period of not less than [***]. During such [***] period, Spero will not offer any Third Party the opportunity to enter into the proposed transaction or enter into any such transaction. If Spero does undergo a Change of Control, the
obligation of Spero (or its successor) to notify Vertex of its intent to license, sublicense or assign rights as provided in this Section 2.5(a) or consummate an additional Change of Control, and Vertex’s right to elect to enter into good
faith negotiations with Spero (or such successor) with respect to a potential transaction, will terminate. 
 (b) Spero will
have the right to grant licenses or sublicenses (through multiple tiers) to a Licensee under the rights licensed to Spero under Section 2.3 (but may not assign such rights); provided that such license or sublicense is granted in
connection with an assignment or grant of rights under Section 2.5(a) and is granted for use solely in connection with the Research, Development, Manufacturing or Commercialization of the Assigned Compounds, Additional Compounds or Products and
subject to Spero’s compliance with Section 2.5(a). 
 2.6. Transfer of Materials. Vertex hereby transfers title and risk of
loss to the Materials to Spero in the quantities specified in Exhibit C. Within [***] after the Effective Date, Spero will either (a) make arrangements with the Third Party storing the Materials (the “Storage Facility”)
to ship the Materials to Spero or (b) enter into an agreement directly with the Storage Facility to continue storing the Materials at Spero’s expense. Vertex will notify the Storage Facility of the transfer of the Materials to Spero as
needed to facilitate the shipment of the Materials to Spero or the continued storage of the Materials by the Storage Facility at Spero’s expense and will execute all transfer letters or other documentation necessary in connection therewith.
Notwithstanding anything contained herein, if Spero does not notify Vertex of its election to either ship or continue storing such Materials with the Storage Facility within [***] after the Effective Date pursuant to this Section 2.6, such
Materials will be deemed to be rejected by Spero and Vertex may destroy the Materials. Except as expressly set forth herein, Spero will be solely responsible for all Manufacturing and supply of the Assigned Compound and Additional Compounds
(including without limitation for all costs and expenses associated therewith). With respect to any such Materials that are drug substances or drug products that were previously certified as to their suitability for clinical purposes, Spero will be
permitted, at its expense, to retest and have recertified, any such Materials, as suitable for human clinical 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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purposes. With respect to any Materials stored by a Storage Facility in any countries or jurisdictions outside of the United States, Spero will be responsible for obtaining, completing and
presenting to the applicable government authorities all export documentation, fees and license(s) required to ship such Materials. 

NOTWITHSTANDING ANYTHING CONTAINED HEREIN, THE MATERIALS ARE PROVIDED “AS-IS” AND VERTEX
MAKES NO REPRESENTATION OR WARRANTIES OF ANY KIND, EITHER EXPRESSED OR IMPLIED, REGARDING THE MATERIALS, INCLUDING ANY WARRANTY OF MERCHANTABILITY, TITLE, INFRINGEMENT, OR FITNESS FOR A PARTICULAR PURPOSE. 

ARTICLE 3. 
 PERFORMANCE
OBLIGATIONS 
 3.1. Regulatory Approvals. As between the Parties, Spero will be responsible for obtaining all necessary
regulatory approvals, including Marketing Approval with respect to the Development, Manufacturing and Commercialization of the Assigned Compounds, Additional Compounds and Products. 

3.2. File/Knowledge Transfer. Within [***] after the Effective Date, Vertex will transfer copies of all Assigned Know-How in electronic format, if currently available, or such other form as mutually agreed by the Parties. Vertex will use commercially reasonable efforts to transfer such Assigned
Know-How and documents promptly. Notwithstanding the foregoing, Vertex will not be obligated to transfer any publically available information or documents pursuant to this Section 3.2. Vertex will provide
Spero with [***] of transition support at [***] for activities related to the knowledge transfer described in this Section 3.2. Notwithstanding anything contained herein, if any of the information or documents transferred pursuant to this
Section 3.2 inadvertently contains any information or documents relating to Vertex drug design, delivery, manufacturing or formulation technology or know-how, or any other technology or know-how that is related to or applicable to Vertex’s business in general or other programs, (a) Spero shall not use such information and, upon discovery, shall promptly send such information or documents
back to Vertex without retaining any copies thereof and (b) for the avoidance of doubt, such information and documents will be deemed Vertex Confidential Information. Spero will promptly reimburse Vertex for any reasonable out-of-pocket expenses incurred by Vertex in connection with the transfer of any Assigned Know-How under this Section 3.2. Vertex
may hold copies of all Assigned Know-How as required to comply with applicable law. 
 ARTICLE 4.

 FINANCIAL PROVISIONS 

4.1. Upfront Payment. In consideration of the rights granted by Vertex to Spero in the Assigned Patents set forth in Exhibit A,
on the Effective Date, Spero will pay to Vertex a one-time, non-refundable, non-creditable upfront fee of $500,000 USD. 

4.2. Milestone Payments. Spero will pay Vertex the milestone payments (each, a “Milestone Payment”) set forth in this
Section 4.2 within [***] after occurrence of the corresponding milestone event (each, a “Milestone Event”). Each Milestone Payment is payable only once, regardless of the number of Products that achieve the relevant Milestone
Event or the number of times Product(s) achieve such Milestone Event. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 11 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 (a) Combination Product Development Milestones. Subject to
Section 4.2(e), Spero will pay Vertex the Milestone Payments set forth in this Section 4.2(a) upon the occurrence of the relevant Milestone Event, with respect to any Combination Product, regardless of whether the relevant Milestone Event
is achieved by Spero or its Related Parties. For clarity, the achievement of a Milestone Event with respect to a Combination Product will not constitute the achievement of the corresponding Milestone Event with respect to a Single Agent Product
under Section 4.2(b). 
  

							
	 Milestone Number
	  	 Milestone Event
	  	Milestone
Payment	 
	 1
	  	[***] a Combination Product [***]	  	$	[	***] 
	 2
	  	[***] a Combination Product	  	$	[	***] 
	 3
	  	[***] a Combination Product	  	$	[	***] 
	 4
	  	[***] a Combination Product	  	$	[	***] 
	 5
	  	[***] a Combination Product	  	$	[	***] 
	 6
	  	[***] a Combination Product	  	$	[	***] 

 (b) Single Agent Product Development Milestones. Subject to Section 4.2(e), Spero
will pay Vertex the Milestone Payments set forth in this Section 4.2(b) upon the occurrence of the relevant Milestone Event with respect to any Single Agent Product, regardless of whether the relevant Milestone Event is achieved by Spero or its
Related Parties. 
  
 Portions of this Exhibit, indicated by the
mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as
amended. 

  
 12 

 CONFIDENTIAL TREATMENT REQUESTED 

 

							
	 Milestone Number
	  	 Milestone Event
	  	Milestone
Payment	 
	 7
	  	[***] a Single Agent Product [***]	  	$	[	***] 
	 8
	  	[***] a Single Agent Product	  	$	[	***] 
	 9
	  	[***] a Single Agent Product	  	$	[	***] 
	 10
	  	[***] a Single Agent Product	  	$	[	***] 
	 11
	  	[***] a Single Agent Product	  	$	[	***] 
	 12
	  	[***] a Single Agent Product	  	$	[	***] 

 (c) Commercial Milestones. Subject to Section 1.39, Spero will pay Vertex the
Milestone Payments set forth in this Section 4.2(c), upon the occurrence of the relevant Milestone Event, regardless of whether the relevant Milestone Event is achieved by Spero or its Related Parties. 

 

							
	 Milestone Number
	  	 Milestone Event
	  	Milestone
Payment	 
	 13
	  	[***]	  	$	[	***] 
	 14
	  	[***]	  	$	[	***] 

 If the Milestone Events numbered 13 and 14 both above [***], both applicable Milestone Payments will be due to
Vertex. 
 (d) Notice; Payment; Skipped Milestones. The Milestones Events numbered
1-3 as set forth in Section 4.2(a) are intended to be successive with respect to Combination Products and the Milestone Events numbered 7-9 as set forth in
Section 4.2(b) are intended to be successive with respect to Single Agent Products; if a Combination Product or Single Agent Product, as applicable, is not required to undergo the event associated with any such Milestone Event, such skipped
Milestone Event will be deemed to have been achieved upon (and payment of such milestone shall be due therefor) the achievement by such Combination Product or Single Agent Product of the next successive Milestone Event. Payment for any such skipped
Milestone Event that is owed in accordance with the provisions of the foregoing sentence with respect to a given Product will be due concurrently with the payment for the next successive event by such Product, it being agreed that if a Product is
not required to undergo Milestone Event number 3 in Section 4.2(a) or Milestone Event number 9 in Section 4.2(b), the corresponding payment will be made upon the first to occur of the Milestone Events numbered 4-6 in Section 4.2(a) or the Milestone Events numbered 10-12 in Section 4.2(b). 

(e) Notwithstanding anything to the contrary contained herein, Spero will only be obligated to pay Vertex for [***] and will
make the corresponding Milestone Payment upon [***]. 
  
 Portions
of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of
the Securities Act of 1933, as amended. 

  
 13 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 4.3. Royalties. 

(a) Net Sales. On a Product-by-Product
and country-by-country basis, Spero will pay to Vertex royalties based on the aggregate Net Sales of all Products sold by Spero or its Related Parties in the Territory
during a Calendar Year at the rates set forth in the table below. The obligation to pay royalties will be imposed only once with respect to the same unit of a Product. 
  

					
	 Calendar Year Net Sales (in Dollars) for all Products
in the
Territory
	  	Royalty Rates as a Percentage
(%) of Net Sales	 
	 Portion of Calendar Year Net Sales up to and including $[***]
	  	 	[	***]% 
	 Portion of Calendar Year Net Sales that exceeds $[***], up to and including $[***]
	  	 	[	***]% 
	 Portion of Calendar Year Net Sales that exceeds $[***], up to and including $[***]
	  	 	[	***]% 
	 Portion of Calendar Year Net Sales that exceeds $[***]
	  	 	[	***]% 

 (b) Royalty Term. Spero will pay royalties to Vertex under this Section 4.3 on a Product-by-Product and country-by-country basis during the Royalty Term. Upon expiration of the
Royalty Term with respect to a given Product in a given country, the licenses granted to Spero under Section 2.3 will be fully paid perpetual and irrevocable with respect to such Product in such country. 

(c) Reduction for Lack of Patent Coverage and Regulatory Exclusivity. If during any period within the applicable Royalty
Term for a country, (a) no valid claim of an Assigned Patent exists that would, but for the licenses granted herein, be infringed by the Research, Development, Manufacture or Commercialization of the relevant Product in such country, and
(b) all applicable Regulatory Exclusivity periods, including data exclusivity periods, have expired in such country with respect to such Product, the royalty rate for such Product in such country will be reduced to [***] percent of the royalty
rate set forth in Section 4.3(a) for the remainder of the Royalty Term. If at any time, royalties are owed under this Section 4.3 with respect to more than one Product and the royalty rate applicable to one Product in one or more
countries, but not all Products in all countries, is reduced pursuant to this Section 4.3(c), then Net Sales of each Product will be allocated across the royalty tiers set forth in Section 4.3(a) pro rata based on the aggregate Net Sales
of each Product as compared to the aggregate Net Sales of all Products. 
 4.4. Payments. 

(a) Reports; Timing and Method. During the Term, following the first sale generating Net Sales of a Product giving rise
to Net Sales, Spero will deliver the following reports to Vertex: (i) within [***] after the end of each Calendar Quarter, a 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 14 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 
flash report showing on a Product-by-Product and
country-by-country basis, estimated Net Sales in the Territory during the relevant Calendar Quarter and royalties payable under this Agreement on account of those Net
Sales; and (ii) within [***] after the end of each Calendar Quarter, a report specifying on a Product-by-Product and country-by-country basis: (A) gross sales in the relevant Calendar Quarter; (B) Net Sales in the relevant Calendar Quarter, including an accounting of Permitted Deductions applied to determine Net
Sales; (C) a summary of the exchange rate calculations used by Spero; (D) royalties payable on such Net Sales pursuant to this Agreement; and (E) additional information related to the Net Sales as reasonably requested by Vertex from
time to time. For the avoidance of doubt, the foregoing reports will clearly identify all Net Sales attributable to Spero as well as Spero’s Related Parties. Spero will pay all royalty payments due hereunder for each Calendar Quarter within
[***] after Spero’s delivery of the applicable reports under this Section 4.4(a). All payments due to Vertex under this Agreement will be made in U.S. dollars and be submitted via wire transfer of immediately available funds to an account
designated by Vertex. Conversion of any Net Sales made in foreign currency to U.S. dollars will be made at the average conversion rate for the applicable Calendar Quarter existing in the United States, as reported in the Wall Street Journal. Such
payments will be without deduction of exchange, collection, or other charges, and specifically, without deduction of withholding or similar taxes or other government-imposed fees or taxes, except as expressly permitted in the definition of Net
Sales. 
 (b) Late Payments. Without limiting any remedy available to Vertex hereunder, payments made by Spero after
the due date will bear interest at the rate of [***] percent per full month late (or, if lower, the highest rate allowed by applicable law). 

(c) Taxes; Withholding. 
  

	 	i.	Each Party will be solely responsible for the payment of all taxes imposed on its share of income arising directly or indirectly from this Agreement. 

 

	 	ii.	To the extent Spero or any Seller is required to deduct and withhold taxes on any payment to Vertex under this Agreement (“Withheld Taxes”), Spero will pay the amounts of Withheld Taxes to the proper
governmental authority in a timely manner and promptly transmit to Vertex an official tax certificate or other evidence of such withholding sufficient to enable Vertex to claim such payment of Withheld Taxes. Subject to the terms of this
Section 4.4(c)(ii), the sum payable by Spero (in respect of which such Withheld Taxes is required) will be made to Vertex after deduction of the Withheld Taxes. Vertex will provide Spero any tax forms that may be reasonably necessary in order
for Spero to not withhold tax or to withhold tax at a reduced rate under an applicable bilateral income tax treaty. Vertex will use reasonable efforts to provide any such tax forms to Spero at least [***] prior to the due date for any payment for
which Vertex desires that 

  
 Portions of this
Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the
Securities Act of 1933, as amended. 

  
 15 

 CONFIDENTIAL TREATMENT REQUESTED 

 

	 	
Spero apply a reduced withholding rate. Each Party will provide the other with reasonable assistance to enable the recovery, as permitted by applicable law, of withholding taxes, value added
taxes, or similar obligations resulting from payments made under this Agreement, such recovery to be for the benefit of the Party bearing such withholding tax or value added tax. 

4.5. Retention of Records; Audit. Spero agrees to make and keep, and will require its Related Parties to make and keep, full, accurate
and complete books and records (together with supporting documentation). Such records will contain sufficient detail to confirm the accuracy of any payments required hereunder. Such records will be retained for at least three years following the end
of the applicable Calendar Year. During normal business hours and no more than once per Calendar Year, Vertex, its duly authorized agent or independent certified public accounting representative acting on Vertex’s behalf (“Third Party
Auditor”) may conduct an audit in order to examine the foregoing books and records described in this Section 4.5 and any other supporting documentation reasonably necessary to verify the royalty reports submitted by Spero, at
Spero’s (or its Related Parties’ as applicable) business premises or at a place mutually agreed upon by the Parties for the purpose of verifying reports and payments hereunder. If a payment deficiency is determined by Vertex or its Third
Party Auditor, Spero will pay the deficiency outstanding within [***] after receiving written notice of the deficiency. Such examination by Vertex or its Third Party Auditor will be at Vertex’s expense, except that, if such examination shows an
underreporting or underpayment in excess of [***] percent of the sums due to Vertex as determined by such audit, then Spero will pay the reasonable out of pocket cost of such audit or reimburse Vertex for the reasonable expenses incurred by Vertex
in connection with such audit. Vertex will treat all information subject to review under this Section 4.5 in accordance with the confidentiality obligations set forth in Article 9 of this Agreement, and any Third Party Auditor to whom Vertex
discloses financial information will be subject to confidentiality obligations with respect to such financial information that are no less restrictive than those contained in this Agreement. 

4.6. Monetization Transaction. Vertex may, at any time, monetize all or a portion of the value of the payments to which it may be
entitled to receive under this Article 4 by assigning to a Third Party (a “Revenue Buyer”) the right to receive such payments (a “Monetization Transaction”); provided that Vertex has put in place
adequate and customary confidentiality provisions at least as stringent as those applicable to Vertex hereunder with the Revenue Buyer. In the event of a Monetization Transaction, Spero will make such payments to the Revenue Buyer as directed by
Vertex and shall deliver notices and provide reports directly to the Revenue Buyer as directed by Vertex. 
 ARTICLE 5. 

REPRESENTATIONS AND WARRANTIES 
  

5.1. Mutual Representations and Warranties. Vertex and Spero each represents and warrants to the other as of the Effective Date that:
(a) such Party (i) is a company duly organized, validly existing, and in good standing under the laws of its jurisdiction of incorporation, (ii) is duly qualified as a corporation and in good standing under the laws of each
jurisdiction where its ownership or lease of property or the conduct of its business requires such 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 16 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 
qualification, where the failure to be so qualified would have a material adverse effect on its financial condition or its ability to perform its obligations hereunder, (iii) has the
requisite corporate power and authority and the legal right to conduct its business as now conducted and (iv) is in compliance with its charter documents; (b) the execution, delivery and performance of this Agreement by such Party and all
instruments and documents to be delivered by such Party hereunder (i) are within the corporate power of such Party, (ii) have been duly authorized by all necessary or proper corporate action, (iii) do not conflict with any provision
of the charter documents of such Party and (iv) will not, to such Party’s knowledge, violate any laws or regulation or any order or decree of any court of governmental instrumentality, (v) will not violate or conflict with any terms
of any indenture, mortgage, deed of trust, lease, agreement, or other instrument to which such Party is a party, or by which such Party or any of its property is bound, which violation would have a material adverse effect on its financial condition
or on its ability to perform its obligations hereunder; and (c) this Agreement has been duly executed and delivered by such Party and constitutes a legal, valid and binding obligation of such Party, enforceable against such Party in accordance
with its terms, except as such enforceability may be limited by applicable insolvency and other laws affecting creditors’ rights generally, or by the availability of equitable remedies. 

5.2. Spero Representations; Legal Compliance; Anti-Corruption Laws. Spero represents and warrants that Spero, as well as all Persons
performing services for or on behalf of Spero or otherwise acting on its behalf (including any agent, subcontractor, subsidiary, representative, employee, shareholder, director or officer) (“Associated Persons”) will comply with all
applicable laws and regulations in connection with all work conducted hereunder, including (a) the United States Foreign Corrupt Practices Act and other applicable anti-corruption and anti-bribery laws (collectively, the
“Anti-Corruption Laws”), (b) all laws and regulations relating to import and export and (c) all laws and regulations relating to the development, testing, marketing, sale, commercialization, and other exploitation of
pharmaceuticals. Without limiting the foregoing, (i) Spero will not (and will procure that each Associated Person will not) perform, or fail to perform, any act that will cause or lead Vertex to be in breach of Anti-Corruption Laws and
(ii) Spero represents and warrants neither it, nor any Associated Person, offers, agrees or promises to give, or authorizes the giving directly or indirectly, of any money or other thing of value to anyone as an inducement or reward for
favorable action or forbearance from action or the exercise of influence (A) to any governmental official or employee (including employees of government-owned and government-controlled corporations or agencies), (B) to any political party,
official of a political party, or candidate, (C) to an intermediary for payment to any of the foregoing or (D) to any other Person or entity in a corrupt or improper effort to obtain or retain business or any commercial advantage, such as
receiving a permit or license. Spero further warrants and represents that should it learn or have reason to suspect any breach of its covenants in this Section 5.2, it will immediately notify Vertex. 

5.3. Vertex Representations and Warranties. Subject to Section 2.1, Vertex hereby represents and warrants that prior to the
Effective Date, Vertex, to its knowledge, has not previously assigned, transferred, conveyed or otherwise encumbered its right, title and interest in and to the Assigned Patents in any way that would prevent Spero or its Affiliates and
subcontractors from Researching, Developing or Commercializing the Assigned Compounds or Products containing the Assigned Compounds as set forth herein, or from exploiting its rights and licenses granted under Article 2 above. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 17 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 5.4. Disclaimer. EXCEPT FOR THE EXPRESS WARRANTIES SET FORTH IN THIS Article 5,
NEITHER VERTEX NOR SPERO MAKES ANY REPRESENTATIONS OR WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, WITH RESPECT TO THE SUBJECT MATTER OF THIS AGREEMENT, INCLUDING WITHOUT LIMITATION ANY WARRANTIES OF MERCHANTABILITY, TITLE, FITNESS FOR A PARTICULAR
PURPOSE, OR NONINFRINGEMENT, EACH OF WHICH ARE HEREBY EXPRESSLY DISCLAIMED. WITHOUT LIMITING THE FOREGOING, EXCEPT FOR THE EXPRESS WARRANTY IN SECTION 5.3, VERTEX MAKES NO WARRANTIES OR REPRESENTATIONS OF ANY KIND OR NATURE WITH RESPECT TO THE
PATENTABILITY OF THE ASSIGNED COMPOUNDS, ADDITIONAL COMPOUNDS, OR PRODUCTS OR VALIDITY, SCOPE, OR ENFORCEABILITY OF THE ASSIGNED PATENTS OR ANY CLAIMS THEREIN, OR THE PRACTICE, INCLUDING BUT NOT LIMITED TO FREEDOM TO OPERATE, REGARDING ANY ASSIGNED
COMPOUND, ADDITIONAL COMPOUND, OR PRODUCT. EXCEPT AS EXPRESSLY SET FORTH IN SECTION 5.3, ALL RIGHTS GRANTED TO SPERO HEREUNDER ARE PROVIDED ON AN AS-IS BASIS. 

ARTICLE 6. 
 COVENANTS

 6.1. At Vertex’s request, Spero will discuss in good faith with a non-profit organization
designated by Vertex the possibility of establishing a relationship with such non-profit organization with respect to discovery, research, development, manufacture and/or commercialization of Products for use
in the treatment of [***]. 
 ARTICLE 7. 

PROGRESS REPORTS 
 7.1.
Progress Reports. Spero will submit [***] progress reports on its efforts to Develop and Commercialize the Assigned Compound and Additional Compounds (“Progress Reports”). Spero will submit the first Progress Report [***] and
subsequent reports every [***] thereafter. 
 Within [***] after the Effective Date, Spero will provide to Vertex a report with respect to
the [***] for the [***] period after the Effective Date and subsequently update such report for the [***] period commencing on January 1st within the first [***] after the end of each Calendar
Year. 
 7.2. Confidential Treatment. Vertex acknowledges and agrees that any reports provided pursuant to Sections 4.4(a) or 7.1 will
constitute the Confidential Information of Spero, except to the extent that they contain information relating to the Licensed Know-How or other Vertex Confidential Information. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 18 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 ARTICLE 8. 

TERM 
 8.1. Term.
This Agreement will commence on the Effective Date and will continue in effect until expiration of all payment obligations under Article 4 (the “Term”). 

8.2. License Termination for Cease in Development. If Spero provides Vertex with notification of its intent to cease all Development
hereunder or if no material Development or Commercialization occurs for a period of 12 consecutive calendar months, Vertex may terminate the license granted pursuant to Section 2.3 upon written notice to Spero, and Spero will immediately cease
all use of the Licensed-Know How following its receipt of such notice. 
 8.3. Surviving Provisions. The following Articles and
Sections will survive expiration of this Agreement: Article 1, Article 4 (to the extent any amounts are due and payable at the time of expiration), Article 6, this Article 8, Article 9, Article 10, Article 11, Article 12, Article 13, Sections 2.1,
2.5, 5.2, 5.4 and 7.2. 
 ARTICLE 9. 

CONFIDENTIALITY 
 9.1.
Confidential Information. Each of Spero and Vertex will (and will cause their respective Affiliates and Licensees to): (a) keep all Confidential Information received from the Disclosing Party confidential with the same degree of care it
maintains the confidentiality of its own Confidential Information; (b) not publish, or allow to be published, and will not otherwise disclose, or permit the disclosure of the Disclosing Party’s Confidential Information in any manner not
expressly authorized pursuant to the terms of this Agreement; and (c) not use, or permit to be used, the Disclosing Party’s Confidential Information for any purpose other than as expressly authorized pursuant to the terms of this
Agreement. No disclosure of the Disclosing Party’s Confidential Information will be made by the Receiving Party to its employees, directors, officers, agents and other Persons unless and until such employees, directors, officers, agents,
contractors and other Persons have agreed in writing to comply with confidentiality and non-use obligations substantially similar to those described herein. Upon termination of this Agreement, the Receiving
Party will return or destroy, at the Disclosing Party’s request, all documents, tapes or other media containing Confidential Information of the Disclosing Party that remain in the Receiving Party’s, its agents’ or contractors’
possession, except that the Receiving Party may keep one copy of the Confidential Information in the legal department files of the Receiving Party, solely for archival purposes and neither the Receiving Party, nor any of its agents, contractors or
other representatives will be required to delete or destroy any electronic back-up tapes or other electronic back-up files that have been created solely by the automatic
or routine archiving and back-up procedures of the Receiving Party or its representatives, to the extent created and retained in a manner consistent with its or their standard archiving and back-up procedures. Such archival copies will be deemed to be the property of the Disclosing Party, and will continue to be subject to the provisions of this Article 9 notwithstanding any expiration of this
Agreement or otherwise. Each Party will be liable for breach of this Article 9 by any of its agents, Related Parties, subcontractors, or its Affiliates’ sublicensees and subcontractors. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 19 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 9.2. Permitted Disclosure and Use. Notwithstanding Section 9.1, a Party may
disclose Confidential Information belonging to the other Party only to the extent such disclosure is reasonably necessary: (a) to obtain Marketing Approval of the Product or any other necessary permissions, approvals and other documents issued
by governmental authorities; provided that all such disclosures pursuant to this subsection 9.2(a) are covered by terms of confidentiality and non-use substantially similar to those set forth
herein; (b) to perform or exercise such Party’s rights under this Agreement; provided that (i) Confidential Information disclosed to such Party’s Affiliates, licensors, licensees or sublicensees, directors,
officers, employees, consultants, representatives or agents, or other Third Parties (including existing or potential acquirers, acquisition targets, collaborators, investment bankers, accountants, attorneys, investors, merger candidates, partners,
venture capital firms or other financial institutions or investors) is, in each case, on a need-to-know basis and solely for business purposes relevant to and permitted
by this Agreement, (ii) each individual and entity to whom such Confidential Information is disclosed is bound in writing to non-use and non-disclosure obligations
no less than substantially as restrictive as those set forth in this Agreement and (iii) the Party making such disclosure shall be liable for such Third Parties’ compliance with such obligations; or (c) to comply with any applicable
law or regulation (including the rules and regulations promulgated by the United States Securities and Exchange Commission or any equivalent governmental agency in any country in the Territory); provided that the Party making such disclosure
will reasonably consider the comments of the other Party regarding confidential treatment sought for any disclosure. If a Party deems it necessary to disclose Confidential Information of the other Party pursuant to this Section 9.2, such Party
will give reasonable advance notice of such intended disclosure to the other Party to permit such other Party sufficient opportunity to object to such disclosure or to take measures to ensure confidential treatment of such information. The Receiving
Party will cooperate reasonably with the Disclosing Party’s efforts to protect the confidentiality of the information. Notwithstanding Section 9.1, Vertex may disclose Spero’s Confidential Information to a Revenue Buyer or a bona fide
potential Revenue Buyer as reasonably necessary in connection with a Monetization Transaction or proposed Monetization Transaction, including a copy of this Agreement and information related to the royalties payable by Spero to Vertex such as
financial reports indicating the amounts that are the subject of the Monetization Transaction, audit reports related to such amounts, if any, and notices and other correspondence; provided that such Confidential Information under or
relating to the subject matter of this Agreement is relevant to the Monetization Transaction; provided further that each recipient of such Confidential Information shall be under an obligation of confidentiality no less protective than the terms of
this Agreement. 
 9.3. Public Announcements. Except as set forth in this Section 9.3 and as required by applicable laws, neither
Party will make any public announcement of any information regarding this Agreement, the Assigned Compounds, Additional Compounds, or any activities under this Agreement without the prior written approval of the other Party (the “Approving
Party”). Notwithstanding the foregoing, within 20 days after the Effective Date, Spero will issue a press release announcing the execution of this Agreement in a form mutually agreed upon by the Parties. Once any statement is approved for
disclosure by the Approving Party or information is otherwise made public in accordance with the preceding sentence, the disclosing Party may make a subsequent public disclosure of the contents of such statement without further approval by the
Approving Party. Notwithstanding the foregoing, Spero will give Vertex the opportunity to review and comment on any proposed public announcement five days prior to 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 20 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 
such public announcement (unless otherwise required by applicable law) and Spero will use good faith efforts to incorporate any suggested changes to any public announcement requested by Vertex
that are for the purpose of protecting the Vertex Confidential Information. 
 9.4. Survival. The obligations and prohibitions
contained in this Article 9 will survive the expiration of this Agreement for a period of [***] years, except with respect to Confidential Information which constitutes a trade secret under applicable law, which will survive for such additional
period of time during which such Confidential Information constitutes the Disclosing Party’s trade secret under applicable law. 

ARTICLE 10. 
 ADDITIONAL
INTELLECTUAL PROPERTY MATTERS 
 10.1. Spero will be solely responsible for filing, prosecution, and maintenance of all of the Assigned
Patents, as well as all internal and external costs and expenses associated therewith. Vertex will have no responsibility or liability for, or relating to, the Assigned Patents. For the avoidance of doubt, Vertex will retain sole ownership of and
all intellectual property rights in and to the Licensed Know-How and does not grant Spero any interest in such Licensed Know-How except as expressly set forth in
Section 2.3 of this Agreement. 
 ARTICLE 11. 

INDEMNIFICATION 
 11.1.
Indemnification by Spero. Spero will defend, indemnify and hold harmless Vertex and its Affiliates and each of their respective officers, directors, shareholders, employees, agents, successors and assigns (“Vertex
Indemnitees”) from and against all charges, complaints, actions, suits, proceedings, hearings, investigations, claims and demands (“Claims”) of Third Parties, and all associated damages and losses resulting therefrom
(including attorneys’ fees), to the extent arising out of (a) any material breach by Spero of its representations, warranties or obligations under this Agreement, or (b) the Research, Development, Manufacturing, Commercialization,
use, licensing, handling, storage, marketing, sale, offer for sale, importation, exportation, distribution or other disposition of, any Assigned Compound, Additional Compound, or Product, including any product Covered by the Assigned Patents or
incorporating the Assigned Know-How, by Spero, its Affiliates, agents, or Licensees. Notwithstanding the foregoing, Spero will have no obligation under this Agreement to indemnify, defend or hold harmless any
Vertex Indemnitees with respect to any such Claims to the extent that they result from the negligence or willful misconduct of Vertex or a Vertex Indemnitee or Vertex’s breach of its obligations under this Agreement. 

11.2. Indemnification by Vertex. Vertex will defend, indemnify and hold harmless Spero and its Affiliates and each of their officers,
directors, shareholders, employees, agents, successors and assigns (“Spero Indemnitees”) from and against all Claims of Third Parties, and all associated damages and losses resulting therefrom, to the extent arising out of any
material breach by Vertex of its obligations under this Agreement. Notwithstanding the foregoing, Vertex will have no obligation under this Agreement to indemnify, defend or hold harmless any Spero Indemnitees with respect to any such Claims and
Losses to the extent that Spero is obligated to indemnify Vertex for such Claim pursuant to Section 11.1. Notwithstanding anything to the contrary in this Agreement, the indemnification provided in this Section 11.2 will be Spero’s
sole and exclusive remedy, and Vertex’s entire liability for, any and all claims, Third Party or otherwise, arising out of or relating to this Agreement or any of the rights granted herein. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 21 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 11.3. Conditions to Indemnification. The obligations of the indemnifying Party under
this Article 11 are conditioned upon the delivery of written notice to the indemnifying Party of any Claim promptly after the indemnified Party becomes aware of such Claim; provided that failure of the indemnified Party to promptly notify the
indemnifying Party of a Claim will not constitute a waiver of, or result in the loss of, the indemnified Party’s right to indemnification under Sections 11.1 or 11.2, as applicable, except to the extent that the indemnifying Party’s
ability to defend against such Claim is materially prejudiced by such failure to notify. The indemnifying Party will have the right to assume control of the defense and/or settlement of any such Claim; provided that the indemnifying Party
will keep the indemnified Party reasonably informed of all material developments in such defense. Notwithstanding the foregoing, the indemnified Party may participate in the defense of any Claim at its sole cost and expense. 

11.4. Settlements. Except for settlements that would solely impose a monetary obligation on the indemnifying Party and for which the
indemnifying Party will by fully responsible, the indemnifying Party will not settle or resolve a Claim or action with respect to such a Claim without the prior written consent of the indemnified Party, such consent not be unreasonably withheld. Any
payment made by a Party to settle any such Claim or action will be at its own cost and expense. 
 ARTICLE 12. 

LIMITATION OF LIABILITY 

12.1. EXCEPT FOR (A) A BREACH BY EITHER PARTY OF Article 9 (CONFIDENTIALITY), (B) SPERO’S INDEMNIFICATION OBLIGATIONS HEREUNDER OR
(C) EITHER PARTY’S FRAUD OR WILFUL MISCONDUCT, NEITHER PARTY WILL BE LIABLE TO THE OTHER WITH RESPECT TO ANY SUBJECT MATTER OF THIS AGREEMENT FOR ANY INDIRECT OR CONSEQUENTIAL DAMAGES, INCLUDING LOST PROFITS, LOSS OF GOODWILL, PUNITIVE OR
INCIDENTAL DAMAGES. VERTEX’S ENTIRE LIABILITY ARISING OUT OF OR RELATING TO THIS AGREEMENT AND ANY SUBJECT MATTER REFERENCED HEREIN UNDER ANY LEGAL OR EQUITABLE THEORY, INCLUDING CONTRACT, NEGLIGENCE, STRICT LIABILITY, OR OTHERWISE WILL NOT
EXCEED $[***] USD. 
 ARTICLE 13. 

MISCELLANEOUS 
 13.1.
Insurance. During the Term of this Agreement and for a period of [***] after the expiration of this Agreement, Spero will obtain and maintain at its sole cost and expense, liability insurance (including without limitation product liability
insurance) in amounts which are reasonable and customary in the Territory for companies who are Developing, Marketing and Commercializing products and services similar to Products. Such liability insurance will insure against all liability,
including without limitation personal injury, physical injury, or property damage arising out of the Manufacture, sale, distribution, or marketing of the Product. Spero will provide written proof of the existence of such insurance to Vertex upon
reasonable request. 
  
 Portions of this Exhibit, indicated by the
mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as
amended. 

  
 22 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 13.2. Assignment. This Agreement may not be assigned by either Party without the prior
written consent of the other Party; provided, however, that either Party may assign this Agreement, in whole or in part, to any of its Affiliates if such Party guarantees the performance of this Agreement by such Affiliate; and
provided further that either Party may assign this Agreement to a successor to all or substantially all of the assets of such Party pertaining to this Agreement pursuant to a Change of Control. This Agreement will be binding
upon, and subject to the terms of the foregoing sentence, inure to the benefit of the Parties hereto, and their permitted successors, legal representatives and assigns. 

13.3. Notices. All demands, notices, consents, approvals, reports, requests and other communications hereunder must be in writing and will be
deemed to have been duly given only if delivered personally, by mail (first class, postage prepaid, certified), or by overnight delivery using a globally recognized carrier, to the Parties at the addresses set forth below or to such other address as
the addressee will have last furnished in writing in accord with this provision to the addressor. All notices will be deemed effective: (a) when delivered if personally delivered on a Business Day (or if delivered or sent on a non-business day, then on the next Business Day); or (b) on receipt if sent by mail or overnight courier. 

If to Vertex: 
 Vertex
Pharmaceuticals Incorporated 
 Attn: Business Development 

50 Northern Avenue 
 Boston,
Massachusetts 02210 
 With a copy to: 

Vertex Pharmaceuticals Incorporated 

Attn: Corporate Legal 
 50
Northern Avenue 
 Boston, Massachusetts 02210 

If to Spero: 
 Spero Therapeutics,
Inc. 
 675 Massachusetts Avenue, 14th Floor 

Cambridge, Massachusetts 02139 

13.4. Severability. In the event of the invalidity of any provisions of this Agreement, the Parties agree that such invalidity will not
affect the validity of the remaining provisions of this Agreement. The Parties will replace an invalid provision with valid provisions which most closely approximate the purpose and economic effect of the invalid provision. Nothing in this Agreement
will be interpreted so as to require either Party to violate any applicable laws, rules or regulations. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 23 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 13.5. Headings. The headings used in this Agreement have been inserted for convenience
of reference only and do not define or limit the provisions hereof. 
 13.6. Waiver. Any term or condition of this Agreement may be
waived at any time by the Party that is entitled to the benefit thereof, but no such waiver will be effective unless expressly set forth in a written instrument duly executed by or on behalf of the Party waiving such term or condition. No provision
of this Agreement will be waived by any act, omission or knowledge of a Party or its agents or employees except as expressly set forth in this preceding sentence. No waiver by any Party of any term or condition of this Agreement, in any one or more
instances, will be deemed to be or construed as a waiver of the same or any other term or condition of this Agreement on any future occasion. Except as expressly set forth in this Agreement, all rights and remedies available to a Party, whether
under this Agreement or afforded by law or otherwise, will be cumulative and not in the alternative to any other rights or remedies that may be available to such Party. 

13.7. Entire Agreement. This Agreement (including the exhibits and schedules hereto) constitutes the entire agreement between the
Parties hereto with respect to the subject matter described herein and supersedes all previous agreements and understandings between the Parties, whether written or oral, including the Mutual Confidentiality Agreement between the Parties dated
January 5, 2015. This Agreement may be altered, amended or changed only by a writing making specific reference to this Agreement and signed by duly authorized representatives of Vertex and Spero. 

13.8. No License. Nothing in this Agreement will be deemed to constitute the grant of any license or other right in either Party, to or
in respect of the Product, Assigned Compound, Additional Compounds, Patent, trademark, Confidential Information, trade secret or other data or any other intellectual property of the other Party, except as expressly set forth herein. 

13.9. Third Party Beneficiaries. None of the provisions of this Agreement will be for the benefit of or enforceable by any Third Party,
including without limitation any creditor of either Party hereto. No such Third Party will obtain any right under any provision of this Agreement or will by reasons of any such provision make any Claim in respect of any debt, liability or obligation
(or otherwise) against either Party hereto. 
 13.10. Counterparts. This Agreement may be executed in any two counterparts, each of
which, when executed, will be deemed to be an original and both of which together will constitute one and the same document. 
 13.11.
Language. This Agreement is written and executed in the English language. Any translation into any other language will not be an official version of this Agreement. In the event of any conflict in interpretation between the English language
version of this Agreement and any other instrument or document related to this Agreement or the business relationship between the Parties contemplated hereby, the English language version of this Agreement will prevail. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 24 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 13.12. Section 365(n) of the Bankruptcy Code. All rights and licenses granted under or
pursuant to any section of this Agreement are, and will otherwise be deemed to be, for purposes of Section 365(n) of the U.S. Bankruptcy Code, licenses of rights to “intellectual property” as defined under Section 101(35A) of the
Bankruptcy Code. Each Party will retain and may fully exercise all of its rights and elections under the Bankruptcy Code or equivalent legislation in any other jurisdiction. Upon the bankruptcy of either Party, the other Party will further be
entitled to a complete duplicate of (or complete access to, as appropriate) any such intellectual property for which a license has been granted to such Party hereunder, and such intellectual property, if not already in its possession, will be
promptly delivered to such other Party, unless the Party in bankruptcy elects to continue, and continues, to perform all of its obligations under this Agreement. 

13.13. Governing Law. This Agreement will be governed by and construed in accordance with the laws of The Commonwealth of Massachusetts,
excluding any conflicts or choice of law rule or principle that might otherwise refer construction or interpretation of this Agreement to the substantive law of another jurisdiction. 

13.14. Independent Parties/Entities. The relationship of Vertex and Spero is that of independent parties and not as agents of each
other, partners, or participants in a joint venture. Vertex and Spero will each maintain sole and exclusive control over their respective personnel and operations. 

13.15. Parent. Parent will cause Spero to perform its obligations under, and to comply with the terms and conditions of, this Agreement.
If Spero fails to perform any of its obligations under this Agreement, Parent shall indemnify Vertex from and against any and all losses, damages, expenses, liabilities, claims, costs or proceedings which Vertex may suffer of incur by reason of such
failure. If Parent undergoes any reorganization, as part of such reorganization, it will provide Vertex with the guarantee set forth in this Section 13.15 from its successor. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 25 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 IN WITNESS WHEREOF, the Parties hereto have caused this Agreement to be executed by their
authorized representatives as of the Effective Date. 
  

			
	 SPERO TRINEM, INC.
	  	 VERTEX PHARMACEUTICALS INCORPORATED

		
	 By: /s/ Ankit
Mahadevia                                    

Name: Ankit Mahadevia

Title:   Director
	  	 By: /s/ David
Altshuler                                        
    
 Name: David Altshuler

Title:   Executive Vice President and Chief

    Scientific Officer

		
	 SPERO THERAPEUTICS, INC.
	  	
		
	 By: /s/ Ankit
Mahadevia                                    

Name: Ankit Mahadevia

Title:   CEO and Director
	  	

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  
 26 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 EXHIBIT A 

Assigned Patents 
 [***]: covers
[***] 
 [***]: covers [***] 
 [***]: [***] 

[***]: covers [***] 
 [***]: covers [***] 

[***]: covers [***] 
 [***]: [***]. 

 

																													
	 Docket

Number
	  	Country	 	 	Status	 	 	Application
Serial No	 	 	Filing
Date	 	 	Patent
Number	 	 	Patent
Issue
Date	 	 	Case
Title	 
	 [***]
	  				 				 				 				 				 				 			
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

																													
	 Docket

Number
	  	Country	 	 	Status	 	 	Application
Serial No	 	 	Filing
Date	 	 	Patent
Number	 	 	Patent
Issue
Date	 	 	Case
Title	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 				 				 				 				 				 			
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  				 				 				 				 				 				 			
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

																													
	 Docket

Number
	  	Country	 	 	Status	 	 	Application
Serial No	 	 	Filing
Date	 	 	Patent
Number	 	 	Patent
Issue
Date	 	 	Case
Title	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  				 				 				 				 				 				 			
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

																													
	 Docket

Number
	  	Country	 	 	Status	 	 	Application
Serial No	 	 	Filing
Date	 	 	Patent
Number	 	 	Patent
Issue
Date	 	 	Case
Title	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  				 				 				 				 				 				 			
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

																													
	 Docket

Number
	  	Country	 	 	Status	 	 	Application
Serial No	 	 	Filing
Date	 	 	Patent
Number	 	 	Patent
Issue
Date	 	 	Case
Title	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  				 				 				 				 				 				 			
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  				 				 				 				 				 				 			
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  				 				 				 				 				 				 			
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 
	 [***]
	  	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 	 	[***]	 	 				 				 	 	[***]	 

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

															
	 Docket

Number
	  	Country	 	Status	 	Application
Serial No	 	Filing
Date	 	Patent
Number	  	Patent
Issue
Date	  	Case
Title
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 		  		  	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 		  		  	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 		  		  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 EXHIBIT B 

Assigned Know-How 

The following Assigned Know-How is located [***]: 

 

											
	 	  	Total
Files	 	Files
in
Folder	 	Size	 	Last
Modified
Date	 	Added
on
Date
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
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	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
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	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

											
	 	  	Total
Files	 	Files
in
Folder	 	Size	 	Last
Modified
Date	 	Added
on
Date
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  		 		 	[***]	 	[***]	 	[***]
	 [***]
	  		 		 	[***]	 	[***]	 	[***]
	 [***]
	  		 		 	[***]	 	[***]	 	[***]
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	  		 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
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	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
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	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
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	  	[***]	 		 	[***]	 	[***]	 	[***]
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	  	[***]	 		 	[***]	 	[***]	 	[***]
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	  	[***]	 		 	[***]	 	[***]	 	[***]
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	  	[***]	 		 	[***]	 	[***]	 	[***]
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	  	[***]	 		 	[***]	 	[***]	 	[***]
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	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

											
	 	  	Total
Files	 	Files
in
Folder	 	Size	 	Last
Modified
Date	 	Added
on
Date
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 	[***]	 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]
	 [***]
	  	[***]	 		 	[***]	 	[***]	 	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 EXHIBIT C 

Materials 
  

			
	 Third Party Storage Facility
	  	Materials
	 [***]
	  	[***]
	 [***]
	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended.EX-10.15

 Exhibit 10.15 

CONFIDENTIAL TREATMENT REQUESTED 

LICENSE AGREEMENT 
 BY
AND BETWEEN 
 MEIJI SEIKA PHARMA CO., LTD. 

AND 
 SPERO OPCO, INC.

  
 Portions of this
Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the
Securities Act of 1933, as amended. 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 TABLE OF CONTENTS 

 

							
	 ARTICLE 1
	 	DEFINITIONS	  	 	1	 
			
	 ARTICLE 2
	 	LICENSE GRANTS	  	 	10	 
			
	 2.1
	 	Meiji Grant	  	 	10	 
	 2.2
	 	Spero Grant	  	 	11	 
	 2.3
	 	Development and Manufacturing Retained Rights	  	 	12	 
	 2.4
	 	Sublicensing	  	 	12	 
	 2.5
	 	Initial File / Knowledge Transfer and Support	  	 	13	 
	 2.6
	 	Reservation of Rights	  	 	13	 
	 2.7
	 	Non-Competing Product	  	 	13	 
			
	 ARTICLE 3
	 	Collaboration structure and activities	  	 	14	 
			
	 3.1
	 	General Responsibilities and Expenses	  	 	14	 
	 3.2
	 	Joint Development Committee	  	 	15	 
	 3.3
	 	Spero Development Plan and Diligence	  	 	16	 
	 3.4
	 	Meiji’s Diligence	  	 	17	 
	 3.5
	 	Meiji Development Plan	  	 	18	 
	 3.6
	 	Ongoing Data Sharing	  	 	18	 
	 3.7
	 	Pharmacovigilance	  	 	18	 
	 3.8
	 	Supply Agreements	  	 	19	 
	 3.9
	 	Joint Commercialization Committee	  	 	19	 
			
	 ARTICLE 4
	 	ECONOMICS	  	 	19	 
			
	 4.1
	 	Upfront Payment	  	 	19	 
	 4.2
	 	Milestone Payments	  	 	19	 
	 4.3
	 	Product Royalty	  	 	19	 
	 4.4
	 	Licensee Revenue	  	 	20	 
	 4.5
	 	Payments	  	 	20	 
	 4.6
	 	Audit Rights	  	 	21	 
			
	 ARTICLE 5
	 	INTELLECTUAL PROPERTY OWNERSHIP, PROTECTION AND RELATED MATTERS	  	 	22	 
			
	 5.1
	 	Ownership of Intellectual Property and Regulatory Documentation	  	 	22	 
	 5.2
	 	Prosecution and Maintenance of Patent Rights	  	 	22	 
	 5.3
	 	Third Party Infringement	  	 	23	 
			
	 ARTICLE 6
	 	CONFIDENTIALITY	  	 	24	 
			
	 6.1
	 	Confidential Information	  	 	24	 
	 6.2
	 	Existence and Terms of Agreement	  	 	25	 
			
	 ARTICLE 7
	 	REPRESENTATIONS AND WARRANTIES; CERTAIN COVENANTS	  	 	25	 
			
	 7.1
	 	Representations, Warranties and Covenants of each Party	  	 	25	 
	 7.2
	 	Representations and Warranties of Meiji	  	 	26	 
	 7.3
	 	Representations and Warranties of Spero	  	 	27	 
	 7.4
	 	No Warranties	  	 	28	 

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  
 ii 

 CONFIDENTIAL TREATMENT REQUESTED 

 

							
			
	 ARTICLE 8
	 	INDEMNIFICATION	  	 	28	 
			
	 8.1
	 	General Indemnification By Meiji	  	 	28	 
	 8.2
	 	General Indemnification By Spero	  	 	28	 
	 8.3
	 	Pfizer Claim	  	 	29	 
	 8.4
	 	Notice	  	 	29	 
	 8.5
	 	Defense	  	 	29	 
	 8.6
	 	Cooperation	  	 	29	 
	 8.7
	 	Settlement	  	 	29	 
			
	 ARTICLE 9
	 	TERM AND TERMINATION	  	 	30	 
			
	 9.1
	 	Term	  	 	30	 
	 9.2
	 	Termination	  	 	30	 
	 9.3
	 	Effects of Expiration or Termination	  	 	32	 
			
	 ARTICLE 10
	 	MISCELLANEOUS	  	 	34	 
			
	 10.1
	 	Assignment; Successors	  	 	34	 
	 10.2
	 	Export Control	  	 	34	 
	 10.3
	 	Compliance with Applicable Laws	  	 	34	 
	 10.4
	 	Choice of Law	  	 	34	 
	 10.5
	 	Dispute Resolution	  	 	34	 
	 10.6
	 	Injunctive Relief	  	 	35	 
	 10.7
	 	Notices	  	 	36	 
	 10.8
	 	Severability	  	 	36	 
	 10.9
	 	Integration	  	 	36	 
	 10.10
	 	English Language	  	 	37	 
	 10.11
	 	Section 365(n)	  	 	37	 
	 10.12
	 	Waivers and Amendments	  	 	37	 
	 10.13
	 	Independent Contractors; No Agency	  	 	37	 
	 10.14
	 	Execution in Counterparts; Facsimile Signatures	  	 	37	 
	 10.15
	 	Exclusions and Limitations of Liability	  	 	38	 
	 10.16
	 	Performance by Affiliates	  	 	38	 
	 10.17
	 	Force Majeure	  	 	38	 
	 10.18
	 	No Third Party Beneficiary Rights	  	 	38	 
	 10.19
	 	Non-exclusive Remedy	  	 	38	 
	 10.20
	 	Interpretation	  	 	39	 
	 10.21
	 	Further Assurances	  	 	39	 
	 10.22
	 	Construction	  	 	39	 
	 10.23
	 	Records Generally	  	 	39	 
	 10.24
	 	Press Releases and Publicity	  	 	39	 

 Exhibit A – Key Terms of Clinical Supply Agreement 

Exhibit B – Compound 
 Exhibit C – Selected Items of WLJ
Know-How 
 Exhibit D – Selected Items of Meiji Know-How 

Exhibit E – Pfizer Letter 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 iii 

 CONFIDENTIAL TREATMENT REQUESTED 

LICENSE AGREEMENT 

This License Agreement (this “Agreement”) is made and effective as of the 14th day of June, 2017 (the “Effective
Date”) by and between Meiji Seika Pharma Co., Ltd., a Japanese corporation with offices at 2-4-16, Kyobashi, Chuo-ku,
Tokyo, 104-8002 Japan (“Meiji”) and Spero OpCo, Inc., a Delaware corporation with offices at 675 Massachusetts Avenue, 14th Floor,
Cambridge, MA 20139, USA (“Spero”). 
 INTRODUCTION 

WHEREAS, Meiji is the party to that certain license agreement (the “WLJ Agreement”) dated as of the [***] day of [***],
between Meiji and Pfizer Japan Inc., as successor to Wyeth Lederle Japan, Ltd. (“Pfizer Japan”), currently a wholly-owned subsidiary of Pfizer Inc.; 

WHEREAS, Meiji owns or has rights to certain WLJ Know-How, Meiji Intellectual Property and Meiji
Regulatory Documentation necessary or useful for Spero to Develop, Manufacture and Commercialize the Compound and the Product; 
 WHEREAS,
Spero desires to be granted by Meiji a license in certain countries to use WLJ Know-How, Meiji Intellectual Property and Meiji Regulatory Documentation for the Development, Manufacture and Commercialization of
the Compound and the Product in such countries, and Meiji desires to grant such a license to Spero, in each case, subject to the terms and conditions set forth herein; and 

WHEREAS, Meiji desires to be granted by Spero a license in certain countries to use Spero Intellectual Property and Spero Regulatory
Documentation for the Development, Manufacture and Commercialization of the Compound and the Product in such countries, and Spero desires to grant such a license to Meiji, in each case, subject to the terms and conditions set forth herein. 

NOW, THEREFORE, for and in consideration of the mutual covenants contained herein, Meiji and Spero hereby agree as follows: 

ARTICLE 1 
 DEFINITIONS

 As used in this Agreement, the following terms shall have the meanings set forth below: 

1.1 “Accounting Standards” means, to the extent applicable to Spero, United States Generally Accepted Accounting Principles or
International Financial Reporting Standards as issued by the International Accounting Standards Board. 
 1.2 “Action” means
any claim, audit, examination, action, cause of action or suit (whether in contract or tort or otherwise), litigation (whether at law or in equity, whether civil or criminal), assessment, arbitration, mediation, investigation, hearing, charge,
complaint, demand, notice or proceeding. 
  
 Portions of this
Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the
Securities Act of 1933, as amended. 

  
 1 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.3 “Affiliate” means, with respect to a Person, another Person that
directly, or indirectly through one or more intermediaries, controls, or is controlled by, or is under common control with, such Person; provided, that for purposes of this definition, “control” means, with respect to a Person at
the relevant time (whether on the Effective Date or at a relevant time during the Term), the possession, directly or indirectly, of the power to direct or cause the direction of the management or policies of such Person, whether through the
ownership of voting securities, by contract, by board of director membership or representation, or otherwise.
 1.4
“Agreement” is defined in the preamble of this Agreement. 
 1.5 “API” means the Compound having a specific
physicochemical property and used as a bulk substance for formulating the Product. 
 1.6 “Approval Application” means new
drug application for the Product that is submitted to the FDA pursuant to 21 C.F.R. 314.3 or similar application or submission for the Product filed with a Regulatory Authority in a country or group of countries to obtain Marketing Approval for a
pharmaceutical product in that country or group of countries. 
 1.7 “Breaching Party” is defined in Section 9.2.2.

 1.8 “Clinical Supply Agreement” is defined in Section 3.8. 

1.9 “Combination Product” means any orally administered pharmaceutical product in finished dosage form for human use
containing the Compound in combination with one or more the Other Active Ingredient(s). 
 1.10 “Commercialize” or
“Commercialization” means to import, export, use, have used, sell, have sold, or offer for sale, commercialize, register, hold, or keep (whether for disposal or otherwise), or otherwise dispose of Products. For clarity,
“Commercialize” and “Commercialization” do not include “Manufacture” and “Manufacturing.” 
 1.11
“Commercially Reasonable Efforts” means efforts that are [***]. 
 1.12 “Compound” means the carbapenem
chemical compound having the generic name, tebipenem pivoxil, the chemical structure of which is set forth in Exhibit B, including [***]. 

1.13 “Confidential Information” means (a) all technical and business information including trade secrets or
confidential or proprietary information or tangible materials of the disclosing Party or its Affiliates provided or disclosed to the other Party or any of its Affiliates pursuant to this Agreement, whether marked as confidential or not, and
(b) the terms and conditions of this Agreement; provided, however, that Confidential Information shall not include information that: 

(i) has been published by a Third Party or otherwise is or hereafter becomes part of the public domain by public use, publication, general
knowledge or the like through no wrongful act, fault or negligence on the part of the receiving Party or its Affiliates; 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 2 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 (ii) has been in the receiving Party’s or its Affiliates possession prior to disclosure
by the disclosing Party without any obligation of confidentiality with respect to such information (as evidenced by the receiving Party’s or such Affiliate’s written records or other competent evidence); 

(iii) is subsequently received by the receiving Party or its Affiliate from a Third Party without restriction and without breach of any
agreement between such Third Party and the disclosing Party; 
 (iv) is generally made available to Third Parties by the disclosing Party
without restriction on disclosure; or 
 (v) has been independently developed by or for the receiving Party or its Affiliates without
reference to, or use or disclosure of, the disclosing Party’s Confidential Information (as evidenced by the receiving Party’s or such Affiliate’s written records or other competent evidence); 

provided, however, that clauses (ii) through (v) above cannot be applied to the terms and conditions of this Agreement. 

1.14 “Control” or “Controlled” means, with respect to any Know-How,
Patent Right, other intellectual property right, compound or product, the legal authority or right (whether by ownership, license (other than a license granted pursuant to this Agreement) or otherwise) of a Party or its relevant Affiliate, to grant
access, a license or a sublicense of or under such Know-How, Patent Right, intellectual property right, compound or product to the other Party, to the extent contemplated by this Agreement, without breaching
the terms of any agreement with a Third Party, or misappropriating the proprietary or trade secret information of a Third Party. 
 1.15
“Cover,” “Covering” or “Covered” means, when referring to a compound or product, Patent Right or Know-How: (a) with respect to an issued patent included
in a Patent Right, that, in the absence of a license granted to a Person under a claim of such Patent Right, the practice by such Person of a specified activity with respect to such compound or product, or the practice by such Person of such Patent
Right or the use by such Person of such Know-How, would infringe such claim, or (b) with respect to a patent application included in a Patent Right, that, in the absence of a license granted to a Person
under a claim included in such patent application, the practice by such Person of a specified activity with respect to such compound or product, or the practice by such Person of an invention claimed in such Patent Right or the use by such Person of
such Know-How, would infringe such claim if such patent application were to issue as a patent. 

1.16 “CTM” is defined in Exhibit A. 

1.17 “Debarred” is defined in Section 7.1.1. 

1.18 “Development” means all activities directed to the development of the Compound and the Product, including GLP toxicology
studies and any other pre-clinical or clinical activities and studies, manufacturing and having the Compound and the Product manufactured for purposes of development and regulatory activities conducted with an
aim to obtain the Marketing Approval; and the term “Develop” shall have correlative meaning. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 3 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.19 “Diligence Milestone” is defined in Section 3.3.2. 

1.20 “Dispute Notice” is defined in Section 10.5. 

1.21 “Disqualified” is defined in Section 7.1.1. 

1.22 “Effective Date” is defined in the Preamble. 

1.23 “Excluded” is defined in Section 7.1.1. 

1.24 “Executive Officer” means (a) a senior executive employee or director of Spero designated by Spero (the “Spero
Executive Officer”) or (b) a senior executive employee or director of Meiji designated by Meiji (the “Meiji Executive Officer”). 

1.25 “FDA” means the United States Food and Drug Administration. 

1.26 “Field” means the treatment, prevention or diagnosis of all diseases in humans. 

1.27 “First Commercial Sale” means, on a
Product-by-Product and country-by-country basis, with respect to a Product in any
country, the first sale for monetary value for use or consumption by the end user of such Product in such country after the Marketing Approval for such Product has been obtained in such country. 

1.28 “ICC” is defined in Section 10.5. 

1.29 “Indemnified Party” is defined in Section 8.4. 

1.30 “Indemnifying Party” is defined in Section 8.4. 

1.31 “Intellectual Property” means any (a) Patent Rights and (b) Know-How.

 1.32 “JCC” is defined in Section 3.9. 

1.33 “JDC” is defined in Section 3.2.1. 

1.34 “Jointly-Generated Intellectual Property” is defined in Section 5.1.2. 

1.35 “Jointly-Generated Patent Rights” means any Patent Rights that Cover the Jointly-Generated Intellectual Property. 

1.36 “Know-How” means any and all information comprising or relating to concepts,
discoveries, data, designs, formulae, composition, protocols, techniques, ideas, materials, inventions, methods, models, assays, research plans, procedures, designs for experiments and tests and results of experimentation and testing, including
results of research or development, together with processes, including manufacturing processes, specifications, techniques, chemical, biological, pharmacological, toxicological, clinical, safety, manufacturing, analytical and quality 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 4 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 control data, trial data, case report forms, data analysis, reports or summaries and information contained in
submissions to and information from ethical committees and governmental entities, in each case (whether or not confidential, proprietary, patented or patentable) in written, electronic or any other form now known or hereafter developed. 

1.37 “KOLs” is defined in Section 3.1.1. 

1.38 “Licensee Revenue” means consideration received by Spero or an Affiliate of Spero from a Sublicensee for the grant of a
sublicense under Section 2.4.1, including upfront payments, and development and sales milestone payments. If any milestone payment made by such Sublicensee is payable based on a milestone event set forth in Section 4.2, the Licensee
Revenue portion of such milestone payment shall include only the amount of the payment received from such Sublicensee that exceeds the amount due from Spero under Section 4.2. Licensee Revenue excludes (x) any amounts reimbursed to Spero
or its Affiliates for patent prosecution and maintenance expenses, and (y) bona fide payments for research and development or other services provided to a Sublicensee by Spero or its Affiliates at commercially reasonable rates. If Spero or its
Affiliate receives any non-monetary consideration, including but not limited to shares of stock, share options and any property from such Sublicensee in consideration for the grant of such sublicense, the fair
market value of such non-monetary consideration appraised in a manner to be agreed between the Parties shall be deemed to be Licensee Revenue. If Spero or an Affiliate of Spero enters into an agreement with a
Sublicensee for the supply of the Compound and/or Product to such Sublicensee, any payment made by such Sublicensee for the Compound and/or Product that exceeds the cost of goods sold plus [***] percent ([***]%) shall be deemed to be the Licensee
Revenue. Running royalties paid by such Sublicensee are subject to Section 4.3 and shall not be deemed to be part of the Licensee Revenue. 

1.39 “Licensee Revenue Cap” is defined in Section 4.4. 

1.40 “Licensee Revenue Share” is defined in Section 4.4. 

1.41 “Losses” means any judgments, awards, suits, fines, liabilities, losses, costs, damages, expenses or amounts paid in
settlement (in each case, including reasonable attorneys’ and experts’ fees and expenses) arising from a Third Party Claim. 
 1.42
“Major Country(ies)” means [***]. 
 1.43 “Manufacture” means the manufacturing of the Compound and/or
Product up to and including finished, packed and labeled drug product, and all activities related to such manufacturing of Compound and/or Product, or any ingredient thereof, either directly or through a contract manufacturer, including in-process and semi-finished Product testing, ongoing stability tests and regulatory activities related to any of the foregoing. “Manufactured” or “Manufacturing” and other forms of the word
“Manufacture” shall have correlative meaning. 
 1.44 “Marketing Approval” means, with respect to a Product in a
particular jurisdiction, all approvals, licenses, registrations or authorizations that are required by the applicable Regulatory Authority for the Commercialization of such Product in such jurisdiction, including, with respect to the United States,
approval of an Approval Application for such Product by the FDA. For clarity, Marketing Approval does not include reimbursement authorization or pricing approval determinations. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 5 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.45 “Milestone Event” is defined in Section 4.2. 

1.46 “Milestone Payment” is defined in Section 4.2. 

1.47 “Meiji” is defined in the Preamble. 

1.48 “Meiji Development and Manufacturing Retained Rights” is defined in Section 2.3.1. 

1.49 “Meiji Development Plan” is defined in Section 3.5. 

1.50 “Meiji Indemnified Parties” is defined in Section 8.2. 

1.51 “Meiji Intellectual Property” means all Meiji Know-How and Meiji Patent Rights.

 1.52 “Meiji Know-How” means all Know-How
Controlled by Meiji, its Affiliates or Sublicensees on the Effective Date or during the Term, that is necessary or useful for the Development, Manufacture and Commercialization of the Compound and/or the Product in the Field, but excluding the Meiji
Regulatory Documentation and WLJ Know-How. The Meiji Know-How includes, but for clarity is not limited to, the items set forth on Exhibit D hereto. 

1.53 “Meiji Patent Rights” means any Patent Rights Covering the Compound and/or the Product that are Controlled by Meiji, its
Affiliates or Sublicensees on the Effective Date or during the Term. 
 1.54 “Meiji Regulatory Documentation” means all
letters, correspondence and other documents and information (in any format) submitted by or on behalf of Meiji, its Affiliates or Sublicensees to Regulatory Authorities in the Meiji Territory, or received from Regulatory Authorities in the Meiji
Territory, relating to the Compound and/or the Product including but not limited to Orapenem. 
 1.55 “Meiji Territory”
means Japan, Bangladesh, Brunei, Cambodia, China, Indonesia, Laos, Malaysia, Myanmar, Philippines, Singapore, South Korea, Taiwan, Thailand and Vietnam. 

1.56 “Memorandum” is defined in Section 10.24.4 

1.57 “Net Sales” means with respect to a Product for any period, the total amount billed or invoiced on sales of such Product
during such period by Spero, its Affiliates, or Sublicensees to Third Parties (including wholesalers or distributors), in bona fide arm’s length transactions, less the following deductions, in each case related specifically to the Product and
actually allowed and taken by such Third Parties and not otherwise recovered by or reimbursed to Spero, its Affiliates, or Sublicensees: (a) trade, cash and quantity discounts; (b) price reductions, rebates or charge backs, retroactive or
otherwise (including Medicare, Medicaid, managed care and other similar types of rebates and chargebacks); (c) taxes on sales (such as sales, value added, or use taxes, but excluding taxes assessed or assessable against the income 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 6 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 derived by Spero, its Affiliates or Sublicensees from such sales) to the extent added to the sale price and
set forth separately as such in the total amount invoiced; (d) amounts repaid or credited by reason of rejections, defects or recalls; (e) freight, insurance, and other transportation charges to the extent added to the sale price and set
forth separately as such in the total amount invoiced; (f) the portion of administrative fees paid during the relevant time period to group purchasing organizations, pharmaceutical benefit managers and/or Medicare prescription drug plans
relating to such Product; (g) any invoiced amounts from a prior period which are not collected and are written off by Spero, its Affiliates or Sublicensees, including bad debts, not to exceed [***] percent ([***]%) of Net Sales; and
(h) that portion of the annual fee on prescription drug manufacturers imposed on Spero, its Affiliates or Sublicensees in the USA by the Patient Protection and Affordable Care Act, Pub. L.
No. 111-148 (as amended), if any, that is allocable to sales of the Products by Spero, its Affiliates or Sublicensees (it being understood that neither Spero nor any of its Affiliates or Sublicensees
shall be permitted to deduct such fees to the extent any other Person has deducted such fees with respect to the sales of the same Product). All of the above deductions shall be consistent with Accounting Standards. 

Net Sales shall not include transfers or dispositions of Product without charge for charitable, promotional,
pre-clinical, clinical, regulatory, or governmental purposes. Net Sales shall include the amount or fair market value of all other consideration received by Spero, its Affiliates or Sublicensees in respect of
the Product, whether such consideration is in cash, payment in kind, exchange or other form, provided that the fair market value of non-monetary consideration shall be appraised in a manner to be agreed
between the Parties. Net Sales shall not include sales between or among Spero, its Affiliates or Sublicensees unless such Affiliate or Sublicensee is the end-user of the Product. 

In the event that a Product is sold in any country or other jurisdiction in a Combination Product, Net Sales for such Product sold as part of
a Combination Product shall be determined by multiplying the net sales of such Combination Product (replacing “Product” with “Combination Product” in the definition of Net Sales above) during the applicable period by the fraction
A/(A+B), where A is the average per unit sale price of such Product when sold separately as a standalone Product in finished form in the country in which the Combination Product is sold and B is the average per unit sale price of the Other Active
Ingredient(s) contained in the Combination Product when sold separately as standalone products in finished form in the country in which the Combination Product is sold, in each case during the applicable period or, if sales of such standalone
Product or Other Active Ingredient(s), as applicable, did not occur in such period, then in the most recent period in which arm’s length fair market sales of such Product or Other Active Ingredient(s), as applicable, occurred. If such average
sale price cannot be determined for such Product or any of the Other Active Ingredient(s), the Parties shall negotiate in good faith to determine what portion of the net sales of such Combination Product in such country or other jurisdiction shall
be treated as “Net Sales” under this Agreement, which determination shall be based on the value added by the Product in such Combination Product, compared to the value added by such Other Active Ingredient(s) in such Combination Product,
to the invoice price of such Combination Product. 
 1.58 “Non-Breaching Party” is
defined in Section 9.2.2 
  
 Portions of this Exhibit,
indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities
Act of 1933, as amended. 

  
 7 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.59 “Orapenem” means the Product in fine granule formulation which Meiji is
commercializing as of the Effective Date. 
 1.60 “Other Active Ingredient” means any component that provides
pharmacological activity or other direct therapeutic effect or that therapeutically affects the structure or any function of the body whereby such component is not the Compound. 

1.61 “Party” means either Meiji or Spero; “Parties” means Meiji and Spero, collectively. 

1.62 “Patent Rights” means any and all (a) national, regional and international patents and patent applications,
including provisional patent applications and right to priority to such applications, (b) patent applications filed either from such patents, patent applications or provisional applications (set forth in (a)) or from an application claiming
priority from either of these, including divisionals, continuations, continuations-in-part, provisionals, converted provisionals and continued prosecution applications,
(c) patents that have issued or in the future issue from the foregoing patent applications (set forth in (a) and (b)), including utility models, petty patents and design patents and certificates of invention, (d) extensions or
restorations by existing or future extension or restoration mechanisms, including revalidations, reissues, re-examinations and extensions (including any supplementary protection certificates and the like) of
the foregoing patents or patent applications (set forth in (a), (b), and (c)), and (e) similar rights, including so-called pipeline protection or any importation, revalidation, confirmation or
introduction patent or registration patent or patent of additions to any of such foregoing patent applications and patents. 
 1.63
“Person” means an individual, corporation, company, partnership, limited liability company, joint venture, association, trust, business trust, governmental entity, unincorporated organization, a division or operating group of any of
the foregoing or any other entity or organization. 
 1.64 “Personnel” is defined in Section 7.1.1. 

1.65 “Pharmacovigilance Agreement” is defined in Section 3.7.2. 

1.66 “Pfizer Claim” is defined in Section 8.3. 

1.67 “Pfizer Japan” is defined in the Preamble. 

1.68 “Pfizer Letter” means the letter between Meiji and Pfizer Japan dated January 9, 2016, the complete copy of which is
attached on Exhibit E hereto. 
 1.69 “Product” means any orally administered pharmaceutical product in finished dosage form
containing the API for human use including but not limited to the Spero New Formulation Product and Orapenem. 
 1.70 “Regulatory
Authority” means any national, regional, state or local regulatory agency, department, bureau, commission, council or other governmental entity with authority over the Development, Manufacture or Commercialization of the Compound and/or the
Product. 
  
 Portions of this Exhibit, indicated by the mark
“[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as
amended. 

  
 8 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 1.71 “Regulatory Exclusivity” means, with respect to any country or other
jurisdiction, an additional market protection, other than patent protection, granted by the Regulatory Authority in such country or other jurisdiction which confers an exclusive commercialization period during which a Party or its Affiliates
or Sublicensees have the exclusive right to manufacture, market or sell a Product in such country or other jurisdiction through a regulatory exclusivity right (e.g., new chemical entity or biologic exclusivity, new use or indication
exclusivity, new formulation exclusivity, orphan drug exclusivity or pediatric exclusivity). 
 1.72 “Royalties” is defined
in Section 4.3. 
 1.73 “Royalty Term” means, on a
Product-by-Product and country-by-country basis, the period beginning on the date of the
First Commercial Sale of such Product in such country and ending on the latest of (i) the date when Regulatory Exclusivity of such Product ends in such country, (ii) the date when all Meiji Know-How,
Meiji Regulatory Documentation and WLJ Know-How have become generally available to the public or ten (10) years from the date of First Commercial Sale of such Product in such country, whichever is earlier
or (iii) the date when the last to expire Valid Claim within the Meiji Patent Rights expires in such country. 
 1.74
“Spero” is defined in the Preamble. 
 1.75 “Spero Indemnified Parties” is defined in Section 8.1.

 1.76 “Spero Intellectual Property” means all Spero Know-How, Spero Patent Rights.

 1.77 “Spero Know-How” means all Know-How
Controlled by Spero, its Affiliates or Sublicensees, on the Effective Date or during the Term, that is necessary or useful for the Development, Manufacture and Commercialization of the Compound and/or the Product in the Field, but excluding the
Spero Regulatory Documentation. 
 1.78 “Spero Development and Manufacturing Retained Rights” is defined in
Section 2.3.2. 
 1.79 “Spero New Formulation Product” means the Product in a formulation which Spero, directly or
indirectly through its Affiliates or Sublicensees, is developing as of the Effective Date or develops during the Term. 
 1.80 “Spero
Patent Rights” means any Patent Rights Covering the Compound and/or the Product that are Controlled by Spero, its Affiliates or Sublicensees on the Effective Date or during the Term. 

1.81 “Spero Regulatory Documentation” means all letters, correspondence and other documents and information (in any format)
submitted by or on behalf of Spero or its Affiliates or Sublicensees to Regulatory Authorities in the Spero Territory, or received from Regulatory Authorities in the Spero Territory, relating to the Compound and/or the Product including but not
limited to Spero New Formulation Product. 
 1.82 “Spero Territory” means worldwide excluding the Meiji Territory. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 1.83 “Sublicensee” means, with respect to a Party or its Affiliate, a Third
Party sublicensee of the rights granted to such Party under this Agreement pursuant to Section 2.4.1 and Section 2.4.2 hereof. 

1.84 “Term” is defined in Section 9.1. 

1.85 “Third Party” means any person or entity other than Spero, Meiji and their respective Affiliates. 

1.86 “Third Party Claim” is defined in Section 8.1. 

1.87 “United States,” “U.S.” “US” or “US Territory” means the United States
of America and its territories and possessions. 
 1.88 “Valid Claim” means a claim of any issued and unexpired patent whose
validity, enforceability, or patentability has not been affected by any of the following: (a) irretrievable lapse, abandonment, revocation, dedication to the public, or disclaimer; or (b) a holding, finding, or decision of invalidity,
unenforceability, or non-patentability by a court, governmental agency, national or regional patent office, or other appropriate body that has competent jurisdiction, such holding, finding, or decision being
final and unappealable or unappealed within the time allowed for appeal. 
 1.89 “WLJ Agreement” is defined in the Preamble.

 1.90 “WLJ Know-How” means all Know-How
relating to the Compound and/or the Product disclosed and provided by Pfizer Japan (or its predecessor) to Meiji under the WLJ Agreement, including all such Know-How that is available to Meiji on the Effective
Date or made available to Meiji during the Term. The WLJ Know-How includes, but for clarity is not limited to, the items set forth on Exhibit C hereto.  

ARTICLE 2 
 LICENSE
GRANTS 
 2.1 Meiji Grant. Subject to the terms and conditions of this Agreement, Meiji hereby grants to Spero, under the Meiji
Intellectual Property, Meiji Regulatory Documentation and WLJ Know-How, a royalty-bearing and exclusive (even as to Meiji) license (but subject to (i) the Meiji Development and Manufacturing Retained
Rights set forth in Section 2.3.1, (ii) the non-exclusive and sublicensable license granted to Pfizer Japan for the Meiji Intellectual Property and Meiji Regulatory Documentation under the WLJ Agreement
and (iii) all rights retained by Pfizer Japan with respect to the WLJ Know-How [***] the Pfizer Letter), with the right to sublicense subject to Section 2.4.1, to Develop, Manufacture and
Commercialize the Compound and the Product in the Field in the Spero Territory. For clarity, the foregoing license includes the right to use, cross-reference, file or incorporate by reference any information and data within the Meiji Regulatory
Documentation to support any regulatory filings in the Spero Territory relating to the Compound and/or the Product. Without limiting the foregoing, Spero hereby agrees to Commercialize the Product solely in the Spero Territory and shall not, and
shall not permit its Affiliates, Sublicensees or distributors to, distribute, market, promote, offer for sale or sell the Product (a) to any Third Party outside the Spero Territory or (b) to any Third Party inside the Spero Territory that
Spero, or its Affiliates, Sublicensees or distributors, as applicable, knows is reasonably likely to distribute, market, promote, offer for sale or sell such Product outside the Spero Territory. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
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 2.2 Spero Grant. 

2.2.1 Subject to the terms and conditions of this Agreement, Spero hereby grants to Meiji, under Spero Intellectual Property and Spero
Regulatory Documentation, (i) a royalty-free and exclusive (even as to Spero) license but subject to the Spero Development and Manufacturing Retained Rights set forth in Section 2.3.2, with the right to sublicense in accordance with
Section 2.4.2, to Develop, Manufacture and Commercialize the Compound and the Product in the Field in the Meiji Territory, and (ii) a royalty-free and non-exclusive license, with the right to
sublicense in accordance with Section 2.4.2, to Develop and Manufacture the Compound and the Product in the Spero Territory solely for the purpose of furthering Development, Manufacturing and Commercialization of the Compound and/or the Product
in the Field in the Meiji Territory. For clarity, the foregoing license includes the right to use, cross-reference, file or incorporate by reference any information and data within the Spero Regulatory Documentation to support any regulatory filings
in the Meiji Territory relating to the Compound and/or the Product. Without limiting the foregoing, Meiji hereby agrees to Commercialize the Product solely in the Meiji Territory and shall not, and shall not permit its Affiliates, Sublicensees or
distributors to, distribute, market, promote, offer for sale or sell the Product (a) to any Third Party outside the Meiji Territory or (b) to any Third Party inside the Meiji Territory that Meiji, or its Affiliates, Sublicensees or
distributors, as applicable, knows is reasonably likely to distribute, market, promote, offer for sale or sell such Product outside the Meiji Territory. 

2.2.2 Subject to the terms and conditions of this Agreement, Spero hereby grants to Meiji a royalty-free, fully
paid-up and perpetual (except as expressly provided in Section 3.4(i)(a)) license, with the right to sublicense in accordance with Section 2.4.2, to use the Jointly-Generated Intellectual Property
for the development, manufacture and commercialization of any compound or product (including the Compound and the Product) in and outside the Field in the Meiji Territory and the Spero Territory, except for the Development, Manufacture and
Commercialization of the Compound and the Product in the Field in the Spero Territory (other than the Development, Manufacture and having Manufactured of the Compound and the Product in the Spero Territory solely for the purpose of furthering
Development, Manufacture and Commercialization thereof in the Field in the Meiji Territory). The license set forth in this Section 2.2.2 shall be (a) exclusive (even as to Spero) as to (i) the Development, Manufacture and
Commercialization of the Compound and the Product in the Field in the Meiji Territory (but subject to the Spero Development and Manufacturing Retained Rights set forth in Section 2.3.2) and (ii) the development, manufacture and
commercialization of any compound or product (including the Compound and the Product) outside the Field in the Meiji Territory and (b) non-exclusive in all other respects. 

Notwithstanding the foregoing, in the event that Meiji desires to use the Jointly-Generated Intellectual Property to (x) Develop,
Manufacture and/or Commercialize the Spero New Formulation Product outside the Field in the Meiji Territory or (y) Develop, Manufacture and/or Commercialize the Compound and/or the Product outside the Field in the Spero Territory, Meiji shall
inform Spero of its intended activities with such use of the Jointly-Generated 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 11 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 Intellectual Property outside the Field and shall discuss the same with Spero through JDC in advance. Spero
shall give due consideration to Meiji’s reasons for such use desired by Meiji. Meiji shall give due consideration to the potential effects of such use on the general clinical utility and commercial potential of the Spero New Formulation Product
in the Spero Territory, as well as then-current ethical and stewardship considerations as generally accepted in the anti-bacterial segment of the pharmaceutical industry. Following such discussion in good faith, if such use is, in Spero’s
reasonable opinion supported with justifiable reasons, likely to have a material adverse effect on the Commercialization of the Spero New Formulation Product by Spero in the Field in the Spero Territory, Meiji shall refrain from such use. 

2.3 Development and Manufacturing Retained Rights. 

2.3.1 Meiji Development and Manufacturing Retained Rights. Meiji shall retain the right under Meiji Intellectual Property, Meiji
Regulatory Documentation and WLJ Know-How, to Develop, Manufacture and have Manufactured the Compound and the Product in the Spero Territory solely for the purpose of furthering Development, Manufacturing and
Commercialization thereof in the Field in the Meiji Territory (the “Meiji Development and Manufacturing Retained Rights”). When Meiji desires to conduct any clinical trial of the Product in the Spero Territory by exercising
the Meiji Development and Manufacturing Retained Rights, Meiji shall provide Spero with an advance notice via the JDC. 
 2.3.2 Spero
Development and Manufacturing Retained Rights. Spero shall retain the right under Spero Intellectual Property, Spero Regulatory Documentation and Jointly-Generated Intellectual Property to Develop, Manufacture and have Manufactured the
Compound and the Product in the Meiji Territory solely for the purpose of furthering Development, Manufacturing and Commercialization thereof in the Field in the Spero Territory (the “Spero Development and Manufacturing Retained
Rights”). When Spero desires to conduct any clinical trial of the Product in the Meiji Territory by exercising the Spero Development and Manufacturing Retained Rights, Spero shall provide Meiji with an advance notice via the JDC.

 2.4 Sublicensing. 

2.4.1 By Spero. Spero shall have the right to grant sublicenses with the right to grant further sublicenses under the rights granted to
Spero pursuant to Section 2.1 to its Affiliates and any Sublicensee; provided that (i) the terms of any sublicense by Spero to its Affiliates and/or Sublicensee shall be in a written agreement and consistent with the terms of this
Agreement, (ii) Spero’s grant of any sublicense shall not relieve Spero from any of its obligations under this Agreement, (iii) Spero shall remain responsible for its Affiliates’ and/or Sublicensees’ performance under this
Agreement, and (iv) Spero shall notify Meiji of the identity of any Affiliate or Sublicensee that receives a sublicense and the territory in which it will grant such sublicense in advance to entering into any such sublicense agreement; and,
provided further, that if such sublicense by Spero involves the grant of a sublicense of the WLJ Know-How to a Sublicensee, prior written consent of Pfizer Japan to such sublicense must be obtained and Meiji
and Spero shall [***] to seek such consent of Pfizer Japan, it being understood that Meiji shall in no event guarantee that such consent can be obtained from Pfizer Japan. For clarity, if Pfizer Japan refuses consent to the sublicense of the WLJ Know-How, (x) Section 9.2.4 shall apply, 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 12 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 and (y) regardless of whether Spero exercises its termination rights under Section 9.2.4, Spero
shall not grant any sublicense under the WLJ Know-How but Spero shall be free to proceed with the sublicense under the Meiji Know-How, Meiji Patent Rights and the Meiji
Regulatory Documentation, subject to the terms and conditions set forth in the first sentence and the following sentence of this Section 2.4.1. Except for the sublicense from Spero solely under the data sets, reports, and other documents listed
on Exhibit D, prior to disclosing any Meiji Know-How to a Sublicensee, the following procedures shall apply: if Spero desires to proceed with sublicensing a particular data set, report or other document other
than those set forth in Exhibit D, Spero shall consult with Meiji whether such specific data set, report, or other document qualifies as WLJ Know-How or Meiji Know-How
and shall abide by Meiji’s determination of such qualification. Meiji represents that the data sets, reports, and other documents listed on Exhibit D are not combined with any items of the WLJ Know-How.

 2.4.2 By Meiji. Meiji shall have the right to grant sublicenses with the right to grant further sublicenses under the rights
granted to Meiji pursuant to Section 2.2 to its Affiliates and any Sublicensee; provided that (i) the terms of any sublicense by Meiji to its Affiliates and/or Sublicensee shall be in a written agreement and consistent with the terms of
this Agreement, (ii) Meiji’s grant of any sublicense shall not relieve Meiji from any of its obligations under this Agreement, (iii) Meiji shall remain responsible for its Affiliates’ and/or Sublicensees’ performance under
this Agreement, and (iv) Meiji shall notify Spero of the identity of any Affiliate or Sublicensee that receives a sublicense and the territory in which it will grant such sublicense in advance to entering into any such sublicense. 

2.5 Initial File / Knowledge Transfer and Support. Upon Spero’s request with at least [***] notice, the Parties will meet on-site at Meiji’s head office in Kyobashi, Tokyo to conduct in-person knowledge transfer relating to the Compound or Product as reasonably requested by Spero. Within
[***] after the Effective Date, Meiji will transfer, on an “as is” basis, copies of all existing WLJ Know-How, Meiji Know-How and Meiji Regulatory
Documentation in electronic format, if currently available, or such other form as mutually agreed by the Parties, including all of the reports and other documents listed on Exhibit C and Exhibit D. Meiji shall provide Spero with reasonable
transition support by Meiji personnel with expertise in the Meiji Know-How at no cost for activities related to the knowledge transfer described in this Section 2.5.

2.6 Reservation of Rights. No rights, other than those expressly set forth in this Agreement are granted to either Party hereunder, and
no additional rights shall be deemed granted to either Party by implication, estoppel or otherwise, with respect to any Intellectual Property rights. All rights not expressly granted by either Party or its Affiliates to the other hereunder are
reserved. 
 2.7 Non-Competing Product. From the Effective Date until the [***] anniversary of
the date of the First Commercial Sale of the first Product in the United States, Spero and its Affiliates and Sublicensees shall not (i) develop, manufacture or commercialize in the Spero Territory any oral dosage formulation of any carbapenem
in the Field other than the Compound and the Product pursuant to this Agreement, and (ii) develop and manufacture for any Third Party, or assist any Third Party in developing, or manufacturing, any oral dosage formulation of 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 13 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 any carbapenem in the Field for commercialization thereof in the Spero Territory other than the Compound and
the Product pursuant to this Agreement. Further, in Japan and any country in the Meiji Territory where Meiji commercializes Orapenem, Spero and its Affiliates and Sublicensees shall not develop, manufacture or commercialize any oral dosage
formulation of any carbapenem which has the same indication as Orapenem in such countries during the Term as long as Meiji commercializes Orapenem in such country(ies). 

ARTICLE 3 
 COLLABORATION
STRUCTURE AND ACTIVITIES 
 3.1 General Responsibilities and Expenses. 

3.1.1 Spero Territory. Except as expressly set forth in this Agreement or as may be otherwise agreed in writing by a duly authorized
representative of Meiji, Spero shall be solely responsible for the Development, Manufacture and Commercialization of the Compound and the Product in the Spero Territory, including obtaining all necessary Marketing Approvals, and for all costs
associated with the foregoing. Furthermore, Spero shall be free to attend and present at medical and scientific conferences and meetings, including meetings with key opinion leaders (“KOLs”), in the Meiji Territory for purposes of
furthering the Development, Manufacture and Commercialization of the Spero New Formulation Product in the Spero Territory, unless such attendance is, in Meiji’s reasonable opinion, likely to have a material adverse effect on the
Commercialization of Orapenem by Meiji in the Meiji Territory. Spero shall notify Meiji in advance through the JDC (or, if appropriate, the JCC) of Spero’s planned attendance at such conferences and meetings in the Meiji Territory to the extent
relating to the Compound and/or the Product. 
 3.1.2 Meiji Territory. Except as expressly set forth in this Agreement or as may be
otherwise agreed in writing by a duly authorized representative of Spero, Meiji shall be solely responsible for Development, Manufacture and Commercialization of the Compound and the Product in the Meiji Territory, including obtaining all necessary
Marketing Approvals, and for all costs associated with the foregoing. Furthermore, Meiji shall be free to attend and present at medical and scientific conferences and meetings, including meetings with KOLs, in the Spero Territory for purposes of
furthering the Development, Manufacture and Commercialization of the Compound and the Product in the Meiji Territory, unless such attendance is, in Spero’s reasonable opinion, likely to have a material adverse effect on the Commercialization of
the Spero New Formulation Product by Spero in the Spero Territory. Meiji shall notify Spero in advance through the JDC (or, if appropriate, the JCC) of Meiji’s planned attendance at such conferences and meetings in the Spero Territory to the
extent relating to the Compound and/or the Product. 
 3.1.3 Cross-Territory Studies. If a Party desires to conduct jointly a clinical
study with sites in both the Spero Territory and the Meiji Territory, the Party shall inform the other Party via the JDC. The JDC will discuss any such proposed joint cross-territory study, including the out-of-pocket financial contributions of each Party, allocation of internal resources, access to data arising therefrom, sponsorship of the study and management of clinical sites, and other matters. If the
JDC reaches agreement in principle on a plan for such a cross-territory study, the senior management of each Party shall review the plan proposed by the JDC, and if 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 14 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 both Parties wish to proceed, the Parties shall negotiate in good faith a written agreement with respect to
such cross-territory study. Notwithstanding anything herein, neither Party shall have any obligation under this Agreement to perform, pay for or contribute to any cross-territory study except as may be set forth in a definitive written agreement
that has received all necessary senior management and board approvals and has been executed by duly authorized representatives of the Parties. 

3.2 Joint Development Committee. 

3.2.1 Formation and Role of Joint Development Committee. The Parties shall, within [***] of the Effective Date, establish a Joint
Development Committee (the “JDC”), comprised of [***] representatives of Spero and [***] representatives of Meiji, at least one of whom from each Party, who shall serve as [***], shall have experience and seniority sufficient to enable him
or her to make decisions on behalf of the Party he or she represents concerning issues within the remit of the JDC. 
 3.2.2
Responsibilities. The JDC shall be responsible for: (i) confirming and preparing annual (or, if needed, more frequent) updates and revisions to the Spero Development Plan for the Spero Territory prepared by Spero and approved by Meiji
pursuant to Section 3.3 and the Meiji Development Plan for the Meiji Territory prepared by Meiji and approved by Spero pursuant to Section 3.3; (ii) monitoring activities and progress under the Spero Development Plan and the Meiji
Development Plan, including the preparation and submission of Approval Applications in the Spero Territory and the Meiji Territory; (iii) overseeing the maintenance of all Marketing Approval of the Spero New Formulation Product in
the Spero Territory and the Meiji Territory, including the performance of post-approval commitments in the Spero Territory and the Meiji Territory; (iv) overseeing the sharing of regulatory correspondence and other regulatory information
relevant to the Development and Commercialization of the Spero New Formulation Product in the Spero Territory and the Meiji Territory, and overseeing planning and submissions for Marketing Approval in the Spero Territory and the Meiji Territory that
are filed; (v) overseeing clinical trials, investigator-initiated trials, post-hoc data analyses, and sponsored research arrangements for the Spero Territory and the Meiji Territory; (vii) discussing
attendance by either or both Parties at medical and scientific conferences and meetings, including meetings with KOLs, in both the Spero Territory and the Meiji Territory; (viii) overseeing medical affairs activities for the Spero Territory and
the Meiji Territory; (ix) developing a publication strategy in the Spero Territory and review procedures for such publications; (x) discussing and determining the details of proposed joint cross-territory studies; and (xi) assuming
such other responsibilities as are set forth in this Agreement, or as mutually agreed in writing by duly authorized representatives of the Parties from time to time. 

3.2.3 Schedule and Minutes. The representatives of the JDC shall mutually agree on the schedule for meetings, provided that there shall
be at least one (1) meeting every [***]. An emergency meeting of the JDC may be held whenever both Parties agree on its necessity. A representative of the Party hosting a meeting of the JDC shall serve as secretary of that meeting. The
secretary of the meeting shall prepare and distribute to all members of the JDC: (a) agenda items at least [***] in advance of the applicable meeting and (b) draft minutes of the meeting within [***] following the meeting to allow adequate
review and comment. Such minutes shall provide a description in reasonable detail of the discussions held at the meeting and 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 15 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 a list of any actions, decisions or determinations approved by the JDC. Minutes of the JDC meeting shall be
approved or disapproved, and revised as necessary, within [***] after their initial circulation in draft form. The final minutes approved by all members of the JDC shall be signed by the representatives of both Parties. Minutes for any subcommittees
shall be prepared in the same manner and in accordance with the same timelines. The final minutes of any subcommittee shall be provided to the JDC. 

3.2.4 Location and Attendance. The location of JDC meetings shall [***], or as otherwise agreed by the Parties. The JDC may also meet by
means of telephone conference call or videoconference, provided that at least [***] per calendar year shall be held in person. Each Party shall use reasonable efforts to cause its representatives to attend JDC meetings. If a Party’s
representative to the JDC or any subcommittee is unable to attend a meeting, such Party may designate an alternate to attend such meeting in place of the absent representative. In addition, each Party may, at its discretion, invite non-voting employees, and, with the consent of the other Party, consultants or scientific advisors, to attend the meetings of the JDC. 

3.2.5 Decision-making. The representatives of each Party shall [***]. The JDC shall [***]. If the Parties are unable to [***], except as
set forth in [***] and as set forth in [***], [***], provided that (i) such decision is consistent with the terms and conditions of this Agreement, and (ii) [***]. For clarity, the JDC shall not [***] this Agreement. 

3.3 Spero Development Plan and Diligence. 

3.3.1 Spero’s Diligence. Spero shall use Commercially Reasonable Efforts to (i) pursue the Development of, (ii) obtain
Marketing Approval of, and (iii) Commercialize [***] in the Spero Territory. 
 3.3.2 Diligence Milestones. Spero shall use
Commercially Reasonable Effort to achieve, by itself or through its Affiliates or Sublicensees, the following diligence milestone targets (the “Diligence Milestones”) with respect to the Product: 

(a) Initiate the first Phase 1 clinical trial for a Product on or before [***] 

(b) [***] on or before [***] 
 (c)
[***] on or before [***]. 
 If Spero reasonably believes that it will not achieve a Diligence Milestone, it may notify Meiji in writing [***] the relevant
deadline together with reasons for not achieving the Diligence Milestone. Spero shall include with such notice a [***] extended and/or amended date for achieving the Diligence Milestone. If Spero so notifies Meiji and provides Meiji with a [***]
extended and/or amended date for achieving the Diligence Milestone, then this Section 3.3.2 shall be amended automatically to incorporate the extended and/or amended Diligence Milestone set forth in the notice. For clarity, if Spero fails to
achieve a Diligence Milestone then, so long as Spero has used and continues to use Commercially Reasonable Efforts to achieve the Diligence Milestones, Meiji shall have no right to terminate this Agreement as a result of such failure. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 16 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 3.3.3 Spero Development Plan. Spero shall prepare and submit to the JDC, for its
review and approval, a development plan with respect to the Development of the Product in the Spero Territory (once approved by the JDC, the “Spero Development Plan”). The Spero Development Plan shall [***] unless Meiji expressly
agrees in writing, in its sole discretion. The Spero Development Plan shall be updated by Spero and submitted to the JDC at least annually. The Spero Development Plan shall include [***]. In the event that the JDC does not approve the Spero
Development Plan as provided in Section 3.2.5, Spero shall have final decision-making authority with respect thereto, including with respect to any activity or other matter that is included in the Spero Development Plan unless Meiji reasonably
determines that the activity or other matter is likely to [***], in which case the activity or matter shall [***]. 
 3.4 Meiji’s
Diligence. Meiji shall have a period of [***] after the receipt of the final study report on the first pivotal study of each Spero New Formulation Product that is the basis for an Approval Application in any of the Major Countries (whether such
pivotal study is a Phase 3 clinical trial or a Phase 2 clinical trial that is the basis for an Approval Application; provided that if the relevant Regulatory Authority requires an additional pivotal study prior to submitting an Approval Application,
the latest clinical trial shall apply) to evaluate, on a formulation-by-formulation basis, (via the JDC) the data generated by Spero relating to such Spero New
Formulation Product. On or before the expiration of such [***] period, Meiji shall provide to Spero a written notice confirming whether Meiji intends to progress the Development, Manufacture and Commercialization of such Spero New Formulation
Product on a country-by-country basis in the Meiji Territory: 

(i) If Meiji fails to provide written notice by such date, or if Meiji informs Spero that Meiji does not intend to progress the Development,
Manufacture and Commercialization of such Spero New Formulation Product (on a formulation-by-formulation and country-by-country basis) in any country in the Meiji Territory, (a) the licenses granted to Meiji set forth in Section 2.2.1 and Section 2.2.2 shall immediately terminate only with respect to
the Development, Manufacture and Commercialization of the Spero New Formulation Product in a country(ies) for which Meiji did not notify Spero of its intention to Develop, Manufacture and Commercialize the Spero New Formulation Product; provided,
however, that all other licenses set forth in Section 2.2.1 and Section 2.2.2 shall remain in effect; and (b) at Spero’s request, Meiji shall grant to Spero, separately from this Agreement, under terms and conditions to be agreed
by the Parties through good faith negotiation the licenses under Meiji Intellectual Property, Meiji Regulatory Documentation and WLJ Know-How, with respect to the Spero New Formulation Product in a
country(ies) for which Meiji did not notify Spero of its intention to Develop, Manufacture and Commercialize the Spero New Formulation Product. 

(ii) If Meiji’s written notice confirms that Meiji does intend to progress the Development, Manufacture and Commercialization of such
Spero New Formulation Product in any country in the Meiji Territory, Meiji shall subsequently use Commercially Reasonable Efforts to Develop and Commercialize such Spero New Formulation Product in such country in the Meiji Territory. If, following
the provision of such notice, Meiji fails to use Commercially Reasonable Efforts to Develop and Commercialize such Spero New Formulation Product in any of the countries designated in such notice, and such failure persists for a period of [***]
Meiji’s rights in such country shall revert to Spero and the provisions of Section 3.4(i) shall apply. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 17 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 3.5 Meiji Development Plan. In the event that Meiji confirms that it does intend to
progress the Development, Manufacture and Commercialization of a Spero New Formulation Product in any country(ies) of the Meiji Territory as contemplated in Section 3.4, Spero and Meiji shall use good faith efforts to agree, through the JDC,
upon a development plan with respect to the Development of the Spero New Formulation Product with use of Spero Intellectual Property, Jointly-Generated Intellectual Property and/or Spero Regulatory Documentation in such country(ies) of the Meiji
Territory (once approved by the JDC, the “Meiji Development Plan”). The Meiji Development Plan shall [***] unless Spero expressly agrees in writing, in its sole discretion. The Meiji Development Plan shall be updated by Meiji and
submitted to the JDC at least annually. The Meiji Development Plan shall include [***]. In the event that the JDC does not approve the Meiji Development Plan, Meiji shall have final decision-making authority with respect thereto, including with
respect to any activity or other matter that is included in the Meiji Development Plan unless Spero reasonably determines that the activity or other matter is likely to [***], in which case the activity or matter shall [***]. For the avoidance of
doubt, except as required pursuant to Section 2.2.2, Meiji shall not be required to report any Development, Manufacture and Commercialization plan and/or activities on the Compound and/or the Product other than the Spero New Formulation
Product. 
 3.6 Ongoing Data Sharing. The Parties, through the JDC, shall exchange the Meiji Intellectual Property, Spero Intellectual
Property, Meiji Regulatory Documentation and Spero Regulatory Documentation throughout the Term in accordance with procedures and timing determined by the JDC, provided that such exchanges shall take place at least biannually. 

3.7 Pharmacovigilance.  

3.7.1 Spero shall own and manage the global safety database for the Product. Spero or its Affiliates shall be responsible for the timely
reporting in the Spero Territory of all relevant adverse drug reactions/experiences, including those associated with Product quality complaints, and aggregate safety data relating to the Product, in accordance with local pharmacovigilance
legislation within the Spero Territory. Meiji shall be responsible for the timely reporting in the Meiji Territory of all relevant adverse drug reactions/experiences, including those associated with Product quality complaints, and aggregate safety
data relating to the Product, in accordance with local pharmacovigilance legislation within the Meiji Territory. The Parties shall exchange safety data described above throughout the Term. 

3.7.2 Further details of the Parties’ respective pharmacovigilance obligations and responsibilities shall be set forth in a
pharmacovigilance agreement that will be agreed to by the Parties (and their respective Affiliate(s), as appropriate) within [***] after the Effective Date (as it may be amended from time to time, the “Pharmacovigilance Agreement”).
In the event of a conflict between the terms of the Pharmacovigilance Agreement and the terms of this Agreement, the provisions of this Agreement shall govern; provided, however, that the Pharmacovigilance Agreement shall govern in respect of
pharmacovigilance, including safety and risk management matters. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 18 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 3.8 Supply Agreements. The Parties agree to negotiate in good faith within
[***] after the Effective Date a new agreement concerning the Development, manufacture and supply of the Spero New Formulation Product for clinical use incorporating the terms set forth on Exhibit A hereto (the “Clinical Supply
Agreement”). Meiji shall have a non-exclusive right to negotiate with Spero for a supply agreement for the Spero New Formulation Product for commercial use in the Spero Territory. No later than [***],
the Parties shall initiate a good faith discussion with respect to a non-exclusive commercial supply agreement for the Spero New Formulation Product, and shall negotiate in good faith to agree on commercially
reasonable terms for such commercial supply agreement. 
 3.9 Joint Commercialization Committee. The Parties shall, within [***] after
the first filing by Spero of an Approval Application for the Product in the Spero Territory, establish a Joint Commercialization Committee (the “JCC”), comprised of [***] representatives of Spero and [***] representatives of Meiji,
at least one of whom from each Party, who shall serve as [***], shall have experience and seniority sufficient to enable him or her to make decisions on behalf of the Party he or she represents concerning issues within the remit of the JCC. The JCC
shall be responsible for sharing information relating to the Parties’ respective Commercialization plans in accordance with a JCC charter to be negotiated in good faith by the Parties prior to the establishment of the JCC. For clarity, subject
to the other terms and conditions of this Agreement, each Party shall have sole control over Commercialization in its Territory except as may otherwise be expressly agreed by the Parties in a writing signed by their respective duly authorized
representatives. 
 ARTICLE 4 

ECONOMICS 
 4.1 Upfront
Payment. In consideration of the rights granted by Meiji to Spero under Section 2.1, within [***] of the Effective Date, Spero shall pay to Meiji a one-time,
non-refundable, non-creditable upfront fee of five hundred thousand US dollars ($500,000). 

4.2 Milestone Payments. In consideration of the rights granted by Meiji to Spero under Section 2.1, Spero shall pay to Meiji the
following milestone payments (each, a “Milestone Payment”) set forth in this Section 4.2 within [***] after occurrence of the corresponding milestone event (each, a “Milestone Event”). Each Milestone Payment is
payable only once, regardless of the number of Products (or formulations) that achieve the relevant Milestone Event or the number of times Product(s) (or formulations) achieve such Milestone Event, and shall be
non-refundable and non-creditable. 
  

							
	Milestone
Number	  	Milestone Event	  	Milestone
Payment	 
	1	  	Enrollment of the first patient or subject in the first Clinical Trial of a Product in the Spero Territory	  	$	1,000,000	 
	2	  	[***]	  	$	[***]	 
	3	  	[***]	  	$	[***]	 

 4.3 Product Royalty. In consideration of the rights granted by Meiji to Spero under Section 2.1,
Spero shall pay to Meiji a royalty on Net Sales of the Products (“Royalties”) at a royalty rate equal to [***] percent ([***]%) on a Product-by-Product
and country-by-country basis during the Royalty Term. Upon the expiration of the Royalty Term for a given Product in a given country, no further royalties shall be
payable on Net Sales of such Product in such country. 
  
 Portions
of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of
the Securities Act of 1933, as amended. 

  
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 CONFIDENTIAL TREATMENT REQUESTED 

 

 4.4 Licensee Revenue. Spero shall pay to Meiji [***] percent ([***]%) of all Licensee
Revenue in US dollars upon Spero’s receipt thereof (the “Licensee Revenue Share”), up to an aggregate amount of seven million five hundred thousand dollars ($7,500,000) (the “Licensee Revenue Cap”). For
clarity, once the Licensee Revenue Cap has been reached, no further Licensee Revenue Share payments shall be due, regardless of the number of Products that have been sublicensed. 

4.5 Payments. 
 4.5.1
Royalties shall become due and payable in US dollars [***] following the end of the calendar quarter during which Net Sales first occur, and within [***] of the end of each calendar quarter thereafter for Net Sales generated during each such
calendar quarter. 
 4.5.2 Within [***] after the end of each calendar quarter following Regulatory Approval of a Product, Spero shall
(i) pay, or cause to be paid, to Meiji an aggregate amount in cash equal to the amount of the Royalties for such calendar quarter and (ii) furnish to Meiji a written report showing in reasonably specific detail, on a Product-by-Product and country-by-country basis the calculation of Net Sales of a Product sold
by Spero and its Affiliates and Sublicensees during such calendar quarter and the calculation of Royalties for such calendar quarter. Spero shall keep complete and accurate records in sufficient detail to enable the Royalties under this Article 4 to
be determined. 
 4.5.3 When Spero receives the Licensee Revenue, Spero shall (i) pay to Meiji the Licensee Revenue Share on such
Licensee Revenue and (ii) furnish to Meiji a written report showing details of such Licensee Revenue and the calculation of the Licensee Revenue Share within [***] after receipt by Spero of such Licensee Revenue or, as the case may be,
completion of the appraisal of the fair market value of such Licensee Revenue if such Licensee Revenue is non-monetary consideration. Spero shall keep complete and accurate records with respect to the Licensee
Revenue in sufficient detail to enable the Licensee Revenue Share to be determined. 
 4.5.4 In the event that Spero fails to pay to Meiji
the upfront payment, Milestone Payment, Royalties and Licensee Revenue Share by the due date, Spero shall pay to Meiji overdue interest at the rate of [***] percent ([***]%) per annum from the due date until completion of the payment in full. Each
payment of the upfront payment, Milestone Payment, Royalties and Licensee Revenue Share due from Spero to Meiji shall be made without any deduction, withholding or offset, except for the withholding tax if withholding tax is required by applicable
tax laws. 
 4.5.5 Meiji shall provide such information and documentation to Spero as are reasonably requested by Spero that are necessary
for Spero to determine if any withholding taxes apply to any payments to be made by Spero to Meiji. Spero shall only make such withholding tax payments to the extent required by applicable laws and shall subtract such required withholding tax
payments that are actually paid by Spero to the appropriate governmental authority responsible for the collection of such withholding tax from the payments due to Meiji. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 20 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 Spero shall promptly submit to Meiji appropriate proof of payment by Spero to the appropriate tax authority
of the required withholding taxes. At the request of Meiji, Spero shall give Meiji such reasonable assistance, which shall include the provision of appropriate certificates of such deductions and withholding tax payments made, together with other
supporting documentation as may be required by the relevant tax authority, to enable Meiji to claim exemption from such withholding tax or to obtain a repayment thereof or a reduction thereof, and shall provide such additional documentation from
time to time as is reasonably requested by Meiji in connection with any of the foregoing. 
 4.5.6 All payments hereunder including upfront
payment, Milestone Payments, Royalties and Licensee Revenue Share shall be payable in US dollars. For Licensee Revenues which Spero receives in any currencies other than US dollars, they shall be translated to US dollars by using the interbank
exchange rate on the date of such receipt quoted by the Wall Street Journal (or any successor publication thereto). For calculation of Royalties, Net Sales shall be first determined in the currency of the countries in which they are earned and then
translated to US dollars by using the interbank exchange rate on the last business day of each calendar quarter quoted by the Wall Street Journal (or any successor publication thereto). 

4.6 Audit Rights. 
 4.6.1
Upon [***] advance written notice by Meiji and not more than once in each calendar year, Spero, its Affiliates and Sublicensees shall permit an independent certified public accounting firm of nationally recognized standing, selected by Meiji and
reasonably acceptable to Spero, to have access (including electronic access, to the extent available and customary for audit purposes) during normal business hours to such of the records of Spero and its Affiliates and Sublicensees as may be
reasonably necessary to verify the accuracy of the reports on the Royalties and Licensee Revenue Share hereunder for the [***] calendar years immediately prior to the date of such request. No calendar year may be audited more than once. The
accounting firm will enter a confidentiality agreement reasonably acceptable to Spero governing the use and disclosure of Spero’s information disclosed to such firm, and such firm shall disclose to Meiji only whether the reports on the
Royalties and Licensee Revenue Share are correct or not and the specific details concerning any discrepancies. Meiji shall treat all financial information disclosed by its accounting firm pursuant to this Section 4.6.1 as Confidential
Information of Spero for purposes of Section 6.1 of this Agreement, and shall cause its accounting firm to do the same. 
 4.6.2 The
written report provided by the accounting firm shall be binding on the Parties absent manifest error. If such accounting firm concludes that the Royalties and/or Licensee Revenue Share paid during the audited period were more or less than the actual
Royalties and/or Licensee Revenue Share due, Spero shall pay any additional amounts due within [***] after the date the written report of the accounting firm so concluding is delivered to Spero, and Spero shall be permitted to deduct any amounts
overpaid from the Royalties and/or Licensee Revenue Share due in the next calendar quarter. The fees charged by such accounting firm shall be paid by Meiji; provided, that if the audit discloses that the Royalties and/or Licensee Revenue
Share payable by Spero for the applicable period have been underpaid by more than [***] percent ([***]%), then Spero shall pay the reasonable fees and expenses charged by such accounting firm. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 21 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 ARTICLE 5 

INTELLECTUAL PROPERTY OWNERSHIP, PROTECTION AND RELATED MATTERS 

5.1 Ownership of Intellectual Property and Regulatory Documentation. 

5.1.1 Ownership of Solely Generated Intellectual Property. As between the Parties, each Party shall solely own any Intellectual Property
that is made or generated solely by employees or contractors of such Party or its Affiliates or Sublicensees. 
 5.1.2 Ownership of
Jointly-Generated Intellectual Property. As between the Parties, any Intellectual Property that is made or generated jointly by Meiji, its Affiliates or Sublicensees and Spero, its Affiliates or Sublicensees during the Term
(“Jointly-Generated Intellectual Property”) shall be solely owned by Spero. Meiji hereby assigns and agrees to make any assignments in the future necessary to accomplish the ownership provisions of this Sections 5.1.2. Meiji has and
will keep in force appropriate agreements with all of its employees and contractors necessary to fully effect this Section 5.1.2, and will impose equivalent obligations on its Affiliates and Sublicensees. Meiji shall execute all documents
reasonably requested by Spero to further evidence, record and perfect the assignments under this Section 5.1.2, and will impose equivalent obligations on its Affiliates and Sublicensees. 

5.1.3 Inventorship. As to the determination on whether any invention is solely generated or jointly generated, the rules of inventorship
under the U.S. Patent Law shall apply. 
 5.1.4 Ownership of Regulatory Documentation. 

(i) As between the Parties, Spero shall exclusively own all Spero Regulatory Documentation (excluding any data generated by or on behalf of
Meiji that is incorporated in the Spero Regulatory Documentation (directly or by cross-reference) from Meiji Regulatory Documentation). Meiji shall have no rights, title or interest in or to the Spero Regulatory Documentation except for the license
and right of reference set forth in Section 2.2. 
 (ii) As between the Parties, Meiji shall exclusively own all Meiji Regulatory
Documentation (excluding any data generated by or on behalf of Spero that is incorporated in the Meiji Regulatory Documentation (directly or by cross-reference) from Spero Regulatory Documentation). Spero shall have no rights, title or interest in
or to the Meiji Regulatory Documentation except for the license and right of reference set forth in Section 2.1. 
 5.2 Prosecution
and Maintenance of Patent Rights. 
 5.2.1 Spero shall solely control the preparation, filing, prosecution and maintenance of the Spero
Patent Rights at its sole expense on a global basis. 
 5.2.2 Meiji shall solely control the preparation, filing, prosecution and maintenance
of the Meiji Patent Rights at its sole expense on a global basis. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 22 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 5.2.3 Spero and Meiji shall in good faith discuss and decide whether a patent application or
similar protection shall be filed for each invention within the Jointly-Generated Intellectual Property. Spero shall control the preparation, filing, prosecution and maintenance of the Jointly-Generated Patent Rights at its sole expense on a global
basis. Spero shall keep Meiji reasonably apprised of material developments regarding the preparation, filing, prosecution and maintenance of Jointly-Generated Patent Rights, and shall provide Meiji with a reasonable opportunity to comment and make
requests regarding the same. Meiji shall provide any comments and make any requests promptly and Spero shall take account of Meiji’ comments and requests in good faith. Meiji shall cooperate with Spero to the extent reasonably necessary for
Spero to prepare, file, prosecute and maintain the Jointly-Generated Patent Rights, including the execution and delivery of documents at no cost to Spero. 

In the event Spero decides that it no longer wishes to prosecute or maintain any particular Jointly-Generated Patent Right in a specific
country, Spero shall notify Meiji and provide Meiji with an opportunity to take over control of the prosecution and/or maintenance of such Jointly-Generated Patent Right in such country at Meiji’ sole expense; provided, however, that if Spero
ceases to prosecute or maintain a Jointly-Generated Patent Right for strategic purposes, as set forth below, Meiji will not be granted the right to take over such activities. A decision to cease prosecution and/or maintenance of a Jointly-Generated
Patent Right in a country shall be deemed to be “strategic” if it is made for reasons that in light of the likely outcomes of prosecution and/or maintenance of such Jointly-Generated Patent Right, cessation of prosecution and/or
maintenance of such Jointly-Generated Patent Right will, in the opinion of Spero and Meiji or, if Spero and Meiji do not reach consensus, in the opinion of outside patent counsel selected by Spero and Meiji, likely be more beneficial for the
protection, validity or enforceability of another Jointly-Generated Patent Right, Spero Patent Rights and/or Meiji Patent Rights in such country or other countries. In the event that Meiji takes over prosecution and maintenance of a
Jointly-Generated Patent Right under this Section 5.2.3(i), Spero shall assign its joint ownership interest to Meiji, free of charge, and such Jointly-Generated Patent Right so assigned shall no longer be deemed to be a Jointly-Generated Patent
Right and shall become a Patent Right owned by Meiji but shall not be deemed to be a Meiji Patent Right licensed to Spero under this Agreement. 

5.3 Third Party Infringement. 

5.3.1 Notice. If, during the Term, either Party learns of any actual, alleged or threatened infringement by a Third Party of the Spero
Patent Rights, the Meiji Patent Rights or Patent Rights in the Jointly-Generated Intellectual Property, such Party shall promptly notify the other Party and shall provide such other Party with available evidence of such infringement. 

5.3.2 Enforcement of Patent Rights. 

(i) Spero shall have the sole right (but not obligation) to institute any infringement Action under Spero Patent Rights in the Spero Territory
and the first right (but not obligation) to institute any infringement Action under Meiji Patent Rights and the Jointly-Generated Patent Rights in the Spero Territory at its expense. In the event that Spero does not exercise the first right to
institute any infringement Action under Meiji Patent Rights and the Jointly-Generated Patent Rights in the Spero Territory, then Meiji shall have the right (but not obligation) to institute any infringement Action under Meiji Patent Rights and the
Jointly-Generated Patent Rights in the Spero Territory at its expense. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 23 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 (ii) Meiji shall have the sole right (but not obligation) to institute any infringement
Action under Meiji Patent Rights in the Meiji Territory and the first right (but not obligation) to institute any infringement Action under Spero Patent Rights and the Jointly-Generated Patent Rights in the Meiji Territory at its expense. In the
event that Meiji does not exercise the first right to institute any infringement Action under Spero Patent Rights and the Jointly-Generated Patent Rights in the Meiji Territory, then Spero shall have the right (but not obligation) to institute any
infringement Action under Meiji Patent Rights and the Jointly-Generated Patent Rights in the Meiji Territory at its expense. 
 5.3.3
Cooperation. In any infringement Action brought by each Party pursuant to Section 5.3.2, the other Party shall, and shall cause its Affiliates to, reasonably cooperate with the Party bringing such infringement Action. 

5.3.4 Orange Book Listings. Spero shall have the sole right to determine which Patent Rights that Cover a Product to list in the
Orange Book in the U.S. or other foreign equivalents in the Spero Territory and shall, at its discretion, undertake, at its costs and expense, to file any relevant information in order to ensure appropriate listing in the Orange Book relating to a
Product. 
 ARTICLE 6 

CONFIDENTIALITY 
 6.1
Confidential Information. 
 6.1.1 Obligations. 

(a) During the Term and for a period of [***] after any termination or expiration of this Agreement, each Party agrees to, and shall cause its
Affiliates to, keep in confidence and not to disclose to any Third Party (except as expressly set forth elsewhere in Section 6.1), or use for any purpose, except to exercise its rights or perform its obligations under this Agreement, any
Confidential Information of the other Party. 
 (b) Each Party agrees that it and its Affiliates shall provide or permit access to the other
Party’s Confidential Information to the receiving Party’s directors, officers, employees, consultants, advisors and Sublicensees, and to the directors, officers, employees, consultants and advisors of the receiving Party’s Affiliates,
in each case who are subject to obligations of confidentiality and non-use with respect to such Confidential Information no less stringent than the obligations of confidentiality and non-use of the receiving Party pursuant to this Section 6.1; provided, that each Party shall remain responsible for any failure by its Affiliates and Sublicensees, and its and its Affiliates’ respective
directors, officers, employees, consultants and advisors, to treat such Confidential Information as required under this Section 6.1 (as if such Affiliates, directors, officers, employees, consultants, advisors and Sublicensees were parties
directly bound to the requirements of this Section 6.1). 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 24 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 6.1.2 Permitted Disclosures. 

(a) Notwithstanding anything to the contrary herein, a receiving Party may disclose the other Party’s Confidential Information to the
extent such disclosure is reasonably necessary to (i) apply for Approval Applications and obtain and/or maintain Marketing Approvals, (ii) file and prosecute patent applications or maintain patents which are filed or prosecuted in
accordance with the provisions of this Agreement, (iii) file, prosecute or defend litigation in accordance with the provisions of this Agreement, (iv) comply with applicable laws, regulations or court orders; provided, however, that if a
receiving Party is required to make any such disclosure, it shall provide prior written notice to the disclosing Party and will use reasonable efforts to assist the disclosing Party in its efforts to secure confidential treatment or a protective
order or to otherwise limit disclosure, or (v) to the extent such disclosure is reasonably necessary, in complying with the terms of agreements with Third Parties related to Products that are entered into after the Effective Date. 

6.2 Existence and Terms of Agreement. Subject to Section 10.24 (Press Releases and Publicity), neither Party may publicly
disclose the existence or terms or any other matter of fact regarding this Agreement without the prior written consent of the other Party, which consent shall not be unreasonably withheld or delayed; provided, however, that either Party may
make such a disclosure (i) to Affiliates, (ii) to potential and actual Sublicensees, investors or sources of financing (in each case who are subject to obligations of confidentiality and non-use with
respect to such Confidential Information no less stringent than the obligations of confidentiality and non-use of the receiving Party pursuant to Section 6.1), (iii) in case of Meiji, to Pfizer Japan and
its parent company Pfizer Inc. to the extent that such disclosure is necessary (x) to seek Pfizer Japan’s consent pursuant to Section 2.4.1, 10.1 or 10.24.4 or Pfizer Japan’s [***] to Spero or (y) to comply with the terms of
the WLJ Agreement (in each case, with imposing on Pfizer Japan and Pfizer Inc. the obligation of confidentiality and non-use no less stringent than the obligations of confidentiality and non-use of Meiji pursuant to Section 6.1) and (iv) to the extent required by law or by the requirements of any nationally recognized securities exchange, quotation system or
over-the-counter market on which such Party has its securities listed or traded. In the event that any such disclosure is required, discloser shall make reasonable
efforts to provide the other Party with prior notice and to coordinate with the other Party with respect to the wording and timing of any such disclosure. 

ARTICLE 7 

REPRESENTATIONS AND WARRANTIES; CERTAIN COVENANTS 

7.1 Representations, Warranties and Covenants of each Party. 

7.1.1 Each Party represents and warrants to the other Party that as of the Effective Date, it and its contractors, and its and their respective
directors, officers and employees who are involved in the performance of any activities under this Agreement relating to the Product (collectively, “Personnel”) have never been and are not currently debarred pursuant to the US
Generic Drug Enforcement Act of 1992, 21 U.S.C. §335(a), as amended, or any similar law or regulation (collectively “Debarred”), excluded by the US Office of Inspector General pursuant to 42 U.S.C. § 1320a-7, et seq. or any agency from participation in any health care program (collectively “Excluded”) or otherwise disqualified or restricted by the US FDA pursuant to 21 C.F.R. 312.70, or
Regulatory Authority (collectively “Disqualified”). 
 7.1.2 Each Party covenants to the other Party that it shall not
employ any Debarred, Excluded or Disqualified Personnel or allow any Debarred, Excluded or Disqualified entity to be involved in any activities relating to this Agreement. Each Party shall notify the other Party promptly if its Personnel are
threatened to become Debarred, Excluded or Disqualified. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 25 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 7.2 Representations and Warranties of Meiji. Meiji represents and warrants to Spero
that, as of the Effective Date: 
 7.2.1 The execution and delivery of this Agreement and the performance of the transactions contemplated
hereby have been duly authorized by all appropriate Meiji corporate action. 
 7.2.2 This Agreement is a legal and valid obligation binding
upon Meiji and enforceable against Meiji in accordance with its terms, subject to the effects of bankruptcy, insolvency or other laws of general application affecting the enforcement of creditor rights, judicial principles affecting the availability
of specific performance and general principles of equity (whether enforceability is considered a proceeding at law or equity), and the execution, delivery and performance of this Agreement by the Parties does not conflict with any agreement,
instrument or understanding to which Meiji is a party or by which it is bound. 
 7.2.3 With respect to the Meiji Intellectual Property (for
clarity, other than any WLJ Know-How that is inseparably combined with Meiji Know-How, which shall be covered by the representation and warranty set forth in
Section 7.2.4) and the Meiji Regulatory Documentation, Meiji has the full right and legal capacity to grant the rights granted to Spero hereunder without violating the right of any Third Party. 

7.2.4 Meiji has obtained Pfizer Japan’s written consent to Meiji’s entering into an agreement with Spero for Meiji to, and Pfizer
Japan’s [***] to (i) supply the Compound to Spero and its Affiliates, (ii) help develop the Product for Spero and its Affiliates, (iii) supply the Product to Spero and its Affiliates and (iv) assist Spero and its Affiliates
with the transfer or license of the WLJ Know-How in the Spero Territory as more fully set forth in the Pfizer Letter, a copy of which has been provided to Spero. 

7.2.5 Neither Meiji nor any of its Affiliates is a party to or otherwise bound by any oral or written contract or agreement that will result in
any Person obtaining any interest in, or that would give to any Person any right to assert any claim in or with respect to, any rights granted by Meiji to Spero under this Agreement. 

7.2.6 Meiji does not own or Control any Intellectual Property that would prevent Spero from exercising the rights granted to it by Meiji under
this Agreement. 
 7.2.7 Neither Meiji nor any of its Affiliates (i) has granted or will during the Term grant any right, license,
encumbrance, consent or privilege that is inconsistent with the rights granted to Spero hereunder or (ii) has entered into or will during the Term enter into any agreements, whether oral or written, that are inconsistent with its obligations
under this Agreement. 
 7.2.8 Meiji is not aware of any Third Party’s Patent Right that would be infringed by making, using, offering
for sale, selling or importing the Compound or the Products. Meiji is not aware of any infringement or misappropriation by a Third Party of any Intellectual Property Controlled by Meiji. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 26 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 7.2.9 The WLJ Agreement is valid and in full force and effect as of the Effective Date, and
neither Meiji nor, to Meiji’s knowledge, Pfizer Japan, is in breach, or has delivered to the other party thereto a notice of breach, of the WLJ Agreement. 

7.2.10 There are no claims, judgments, or settlements against Meiji or any of its Affiliates relating to the WLJ
Know-How or Meiji Know-How. No claim or litigation has been brought or, to Meiji’s knowledge, threatened against Meiji by any Person alleging the misappropriation
of the WLJ Know-How or Meiji Know-How. 
 7.2.11 To
Meiji’s knowledge, no material breach of confidentiality vis-à-vis Meiji has been committed by any Third Party with respect to the Meiji Know-How or WLJ Know-How and Meiji has used reasonable measures to protect the confidentiality thereof. 

7.2.12 To Meiji’s knowledge, all written data, results and other information disclosed by Meiji to Spero at any time prior to the
Effective Date relating to the Compound, the Product or the Meiji Intellectual Property or, assuming WLJ Know-How obtained from Pfizer Japan is true and accurate, WLJ
Know-How is true and accurate in all material respects, and did not omit important information known to Meiji that would be required to be disclosed in order to make such data, results and other information
that was disclosed to Spero not misleading in any material respect. 
 7.3 Representations and Warranties of Spero. Spero represents
and warrants to Meiji that, as of the Effective Date: 
 7.3.1 The execution and delivery of this Agreement and the performance of the
transactions contemplated hereby have been duly authorized by all appropriate Spero corporate action. 
 7.3.2 This Agreement is a legal and
valid obligation binding upon Spero and enforceable in accordance with its terms, subject to the effects of bankruptcy, insolvency or other laws of general application affecting the enforcement of creditor rights, judicial principles affecting the
availability of specific performance and general principles of equity (whether enforceability is considered a proceeding at law or equity), and the execution, delivery and performance of this Agreement by the Parties does not conflict with any
agreement, instrument or understanding to which Spero is a party or by which it is bound. 
 7.3.3 Spero has the full right and legal
capacity to grant the rights granted to Meiji hereunder without violating the rights of any Third Party. 
 7.3.4 Neither Spero nor any of
its Affiliates (i) has granted or will during the Term grant any right, license, encumbrance, consent or privilege that is inconsistent with the rights granted hereunder or (ii) has entered into or will during the Term enter into any
agreements, whether oral or written, that are inconsistent with its obligations under this Agreement. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 27 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 7.3.5 Spero does not own or Control any Intellectual Property that would prevent Meiji from
exercising the rights granted to it by Spero under this Agreement. 
 7.3.6 Spero is not aware of any Third Party’s Patent Right that
would be infringed by making, using, offering for sale, selling or importing the Compound or the Products. Spero is not aware of any infringement or misappropriation by a Third Party of any of the Spero Intellectual Property. 

7.3.7 There are no claims, judgments, or settlements against Spero or any of its Affiliates relating to the Spero Know-How. No claim or litigation has been brought or, to Spero’s knowledge, threatened against Spero by any Person alleging the misappropriation of the Spero Know-How.

 7.3.8 To Spero’s knowledge, no material breach of confidentiality has been committed by any Third Party with respect to the Spero Know-How and Spero has used reasonable measures to protect the confidentiality thereof. 
 7.4 No
Warranties. Except as expressly set forth in this Agreement, NEITHER PARTY MAKES ANY REPRESENTATION OR EXTENDS ANY WARRANTIES OF ANY KIND, EITHER EXPRESS OR IMPLIED. THERE ARE NO EXPRESS OR IMPLIED WARRANTIES OF MERCHANTABILITY OR FITNESS FOR A
PARTICULAR PURPOSE, OR OF NON-INFRINGEMENT OF ANY PATENT, COPYRIGHT, TRADEMARK, OR OTHER RIGHTS OF THIRD PARTIES, OR ANY OTHER EXPRESS OR IMPLIED WARRANTIES. 

ARTICLE 8 

INDEMNIFICATION 
 8.1
General Indemnification By Meiji. Meiji shall defend, indemnify and hold harmless Spero, its Affiliates and their respective directors, officers, employees and agents (collectively, the “Spero Indemnified Parties”), from,
against and in respect of any and all Actions brought by a Third Party (a “Third Party Claim”) and Losses incurred or suffered by any Spero Indemnified Party to the extent such Third Party Claims and Losses arise from: (a) any
breach of, or inaccuracy in, any representation or warranty made by Meiji in this Agreement, or any breach or violation by Meiji of any covenant or agreement in this Agreement; (b) the negligence or intentional misconduct of, or violation of
law by, Meiji, any of its Affiliates or Sublicensees, or any of their respective directors, officers, employees and agents, in performing Meiji’s obligations or exercising Meiji’s rights under this Agreement; (c) the Development,
Manufacture or Commercialization of a Compound or a Product by Meiji or any of its Affiliates or Sublicensees; or (d) the development, manufacture or commercialization of a compound or a product that is developed or manufactured using any
Jointly-Generated Intellectual Property by Meiji or any of its Affiliates or Sublicensees. 
 8.2 General Indemnification By Spero.
Spero shall defend, indemnify and hold harmless Meiji, its Affiliates and their respective directors, officers, employees and agents (collectively, the “Meiji Indemnified Parties”), from, against and in respect of any and all Third
Party Claims and Losses incurred or suffered by any Meiji Indemnified Party to the extent such 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 28 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 Third Party Claims and Losses arise from: (a) any breach of, or inaccuracy in, any representation or
warranty made by Spero in this Agreement or any breach or violation by Spero of any covenant or agreement in this Agreement; (b) the negligence or intentional misconduct of, or violation of law by, Spero, any of its Affiliates or Sublicensees,
or any of their respective directors, officers, employees and agents, in performing Spero’s obligations or exercising Spero’s rights under this Agreement; or (c) the Development, Manufacture or Commercialization of a Compound or a
Product by Spero or any of its Affiliates or Sublicensees. 
 8.3 Pfizer Claim. Each Party’s indemnification obligations set
forth in Section 8.1 and Section 8.2 shall not apply to any Actions brought by Pfizer Japan (“Pfizer Claim”) and Losses incurred or suffered by a Spero Indemnified Party or a Meiji Indemnified Party, as applicable, as a
result of the Pfizer Claim, except in case where the Pfizer Claim arises from or is attributable to any event set forth in item (a) or (b) of Section 8.1 or item (a) or (b) of Section 8.2, in which case each Party’s
indemnification obligations shall apply to the Pfizer Claim in accordance with item (a) or (b) of Section 8.1 or item (a) or (b) of Section 8.2, as applicable. 

8.4 Notice. A Spero Indemnified Party or Meiji Indemnified Party, as applicable, (the “Indemnified Party”) shall give
prompt written notification to the Party from whom indemnification is sought (the “Indemnifying Party”) of the commencement of Third Party Claim or, if earlier, upon the assertion of such Third Party Claim by a Third Party;
provided, however, that failure by the Indemnified Party to give notice of a Third Party Claim as provided in this Section 8.4 shall not relieve the Indemnifying Party of its indemnification obligation under this Agreement, except and only to
the extent that the Indemnifying Party is actually prejudiced as a result of such failure to give notice. 
 8.5 Defense. Within [***]
after delivery of a notice of any Third Party Claim in accordance with Section 8.4, the Indemnifying Party may, upon written notice thereof to the Indemnified Party, assume control of the defense of such Third Party Claim with counsel
reasonably satisfactory to the Indemnified Party. If the Indemnifying Party does not assume control of such defense, the Indemnified Party shall control such defense. The Party not controlling such defense may participate therein at its own expense,
unless the Indemnifying Party has not assumed control of such Third Party Claim, in which case such expenses shall be borne by the Indemnifying Party. 

8.6 Cooperation. The Party controlling the defense of any Third Party Claim shall keep the other Party advised of the status of such
Third Party Claim and the defense thereof and shall reasonably consider recommendations made by the other Party with respect thereto. The other Party shall reasonably cooperate with the Party controlling such defense and its Affiliates and agents in
defense of the Third Party Claim, with all out-of-pocket costs of such cooperation to be borne by the Indemnifying Party. 

8.7 Settlement. The Indemnified Party shall not agree to any settlement of such Third Party Claim without the prior written consent of
the Indemnifying Party, which shall not be unreasonably withheld. The Indemnifying Party shall not, without the prior written consent of the Indemnified Party, which shall not be unreasonably withheld, agree to any settlement of such Third Party
Claim or consent to any judgment in respect thereof that does not include a complete and unconditional release of the Indemnified Party from all liability with respect thereto or that imposes any liability or obligation on the Indemnified Party.

  
 Portions of this Exhibit, indicated by the mark
“[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as
amended. 

  
 29 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 ARTICLE 9 

TERM AND TERMINATION 
 9.1
Term. Unless terminated earlier in accordance with this Article 9, this Agreement becomes effective as of the Effective Date and shall continue in effect until, and expire upon, on a country-by-country basis, the later of (i) the end of the Royalty Term in such country or (ii) if Spero is still receiving Licensee Revenue from a Sublicensee in such country at the end of the
Royalty Term and the Licensee Revenue Cap has not been reached, the date upon which the Licensee Revenue Cap has been reached (the “Term”). 

9.2 Termination. 
 9.2.1
Voluntary Termination. Spero may, after [***] Meiji, terminate this Agreement, by providing Meiji with notice in writing that Spero intends to abandon all the Development and Commercialization of the Compound and the Product in any countries
in the Spero Territory because efficacy, safety, unanticipated regulatory requirements or restrictions, or business factors (such as, but not limited to, higher-than-anticipated costs of Development, Manufacture or Commercialization; unfavorable
reimbursement projections; or the likelihood of competition from products being developed or commercialized by third parties) do not justify Spero’s continued Development or Commercialization of the Compound and/or the Product in the Spero
Territory. If Spero provides such notice of termination, (i) this Agreement shall remain in full force and effect until the effective date of such termination, and (ii) at Meiji’s request, Spero shall [***] the transfer of the Spero
Regulatory Documentation to Meiji [***]. 
 9.2.2 Termination for Material Breach. Upon any material breach of this Agreement by
either Party (the “Breaching Party”), the other Party (the “Non-Breaching Party”) shall have the right, but not the obligation, to terminate this Agreement in its entirety by
providing [***] written notice to the Breaching Party, which notice shall, in each case (a) expressly reference this Section 9.2.2, (b) reasonably describe the alleged breach which is the basis of such termination, and (c) clearly
state the Non-Breaching Party’s intent to terminate this Agreement if the alleged breach is not cured within the applicable cure period. The termination shall become effective at the end of the notice
period unless the Breaching Party cures such breach during such notice period; provided, that, the Non-Breaching Party may, by notice to the Breaching Party, designate a later date for such termination.
Notwithstanding the foregoing, (1) if such material breach, by its nature, is curable, but is not reasonably curable within the applicable cure period, then such cure period shall be extended if the Breaching Party provides a written plan for
curing such breach to the Non-Breaching Party and uses diligent efforts to cure such breach in accordance with such written plan; provided, that no such extension shall exceed [***] without the consent
of the Non-Breaching Party. If the Breaching Party fails to cure such material breach within such [***] period, or such longer period of time as the Parties may agree, then the
Non-Breaching Party may terminate this Agreement upon written notice to the Breaching Party as provided in this Section 9.2.2. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 30 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 9.2.3 Termination for Insolvency. In the event that either Party (a) files for
protection under bankruptcy or insolvency laws, (b) makes an assignment for the benefit of creditors, (c) appoints or suffers appointment of a receiver or trustee over substantially all of its property that is not discharged within ninety
(90) days after such filing, (d) proposes a written agreement of composition or extension of its debts, (e) proposes or is a party to any dissolution or liquidation, (f) files a petition under any bankruptcy or insolvency act or
has any such petition filed against it that is not discharged within sixty (60) days of the filing thereof, or (g) admits in writing its inability generally to meet its obligations as they fall due in the general course, then the other
Party may terminate this Agreement in its entirety effective immediately upon written notice to such Party. In the event Meiji terminates this Agreement pursuant to this Section 9.2.3 and if legally permissible, Spero shall, at Meiji’s
request, transfer to Meiji the Spero Regulatory Documentation for reasonable monetary consideration to be agreed by the Parties through good faith negotiation. 

9.2.4 Spero Termination Rights Relating to WLJ Agreement. Spero shall have the right, in its sole discretion, to terminate this
Agreement and return to Meiji all WLJ Know-How in Spero’s possession that constitutes Meiji’s Confidential Information, if any of the following circumstances arise: 

(i) Either the WLJ Agreement or the Pfizer Letter is validly terminated by Pfizer Japan, except in case where such termination is due to any
event set forth in item (a) or (b) of Section 8.2; 
 (ii) If a Pfizer Claim is made against Spero or any of its Affiliates or
Sublicensees for reasons of this Agreement except in case where such Pfizer Claim arises or is attributable to any event set forth in item (a) or (b) of Section 8.2; 

(iii) If the WLJ Agreement [***] in any material respect, or otherwise [***] which have a material impact on Development or Commercialization
of the Compound and/or the Product by Spero or its Affiliates, provided that Spero gives Meiji written notice of such termination [***], provided that [***]; 

(iv) Pfizer Japan refuses a request made pursuant to Section 2.4.1, 10.1, or 10.24.4, and such refusal has a material impact on
Development or Commercialization of the Compound or the Product by Spero under this Agreement; or 
 (v) Meiji cannot [***], no later than
[***] after the Effective Date or [***] before the implementation of the due diligence requirements described in this Section 9.2.4(v), whichever comes first, (a) to Spero, its Affiliates and potential and actual Sublicensees, investors or
sources of financing or their counsel (subject to confidentiality obligations consistent with this Agreement) to satisfy the due diligence requirements of Spero’s potential and actual Sublicensees, investors or sources of financing or their
counsel, or (b) to the extent required by applicable law, rule or regulation or by the requirements of any nationally recognized securities exchange, quotation system or
over-the-counter market on which Spero or a relevant Affiliate of Spero has its securities listed or traded, or proposed to be listed or traded, provided that [***].

  
 Portions of this Exhibit, indicated by the mark
“[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as
amended. 

  
 31 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 For the avoidance of doubt, any of the above circumstances shall not be deemed to constitute a breach of this
Agreement by Meiji, and (a) Meiji shall not be required to reimburse any payments made by Spero hereunder prior to the date of such termination and (b) Meiji shall not owe any liability to Spero due to such termination, except to the
extent that such liability arises under a provision of this Agreement other than this Section 9.2.4. 
 9.3 Effects of Expiration or
Termination. In the event of expiration or termination of this Agreement for any reason, the provisions of this Section 9.3 shall apply. 

9.3.1 Effects of Expiration on Licenses. Upon the expiration of the Term of this Agreement in accordance with Section 9.1, all
licenses granted by Spero to Meiji under Section 2.2.1, and all licenses granted by Meiji to Spero under Section 2.1, shall survive and become fully-paid up and perpetual. 

9.3.2 Return of Confidential Information. Within [***] after the effective date of expiration or termination of this Agreement in its
entirety, or earlier if requested by a Party, each Party shall, and shall cause its Affiliates to (a) destroy, all tangible items solely comprising, bearing or containing any Confidential Information of the other Party that are in such first
Party’s or its Affiliates’ possession or control, and provide written certification of such destruction, or (b) prepare such tangible items of the other Party’s Confidential Information for shipment to such other Party, as such
other Party may direct, at the first Party’s expense; provided, that, in any event, each Party may retain one copy of the Confidential Information of the other Party to the extent necessary to exercise its rights or perform its
obligations that survive expiration or termination of this Agreement. 
 9.3.3 Effects of Termination on Licenses. 

(a) In the event of any termination of this Agreement by Meiji under Section 9.2.2 or 9.2.3, (i) all licenses granted by Meiji to Spero
under Section 2.1 shall terminate, and (ii) all licenses granted by Spero to Meiji under Section 2.2.1 shall survive and become fully-paid up and perpetual. In the event of any such termination, at Meiji’s request, and
subject to any continuing rights of Spero’s Sublicensees, Spero shall negotiate in good faith for the transfer of the Regulatory Documentation to Meiji and the possible expansion of the licenses granted to Meiji beyond the scope set forth in
the preceding sentence. 
 (b) In the event of any termination of this Agreement by Spero under Section 9.2.1, (i) all licenses granted
by Spero to Meiji under Section 2.2.1 shall survive and become fully-paid up and perpetual, and (ii) all licenses granted by Meiji to Spero under Section 2.1 shall terminate. In the event of any such termination, at Meiji’s
request, and subject to any continuing rights of Spero’s Sublicensees, Spero shall negotiate in good faith for the transfer of to Meiji and the possible expansion of the licenses granted to Meiji beyond the scope set forth in the preceding
sentence. 
 (c) In the event of any termination of this Agreement by Spero under Section 9.2.2 or 9.2.3, (i) all licenses granted by
Spero to Meiji under Section 2.2.1 shall terminate, and (ii) all licenses granted by Meiji to Spero under Section 2.1 shall survive and become fully-paid up and perpetual. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 32 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 (d) In the event of any termination of this Agreement by Spero under Section 9.2.4, (i)
all licenses granted by Spero to Meiji under Section 2.2.1 shall survive and become fully-paid up and perpetual, subject to the last sentence of Sections 2.2.1 and (ii) all licenses granted by Meiji to Spero under Section 2.1 shall
survive and become perpetual and freely sublicensable but be limited to exclude the WLJ Know-How. Following such termination, so long as Spero or its Affiliates or Sublicensees continue to exercise the
licenses granted to Spero under Section 2.1, Spero shall continue to pay royalties, Licensee Revenue Share and milestone payments to Meiji subject to, and in accordance with, the provisions of Article 4. 

9.3.4 Non-Exclusive Remedy. Notwithstanding anything herein to the contrary, termination of this
Agreement shall be without prejudice to other remedies any Party may have at law or equity. 
 9.3.5 Survival. Termination or
expiration of this Agreement shall not relieve either Party of any obligation accruing prior to expiration or termination. Section 4.5 (Payments) shall survive only until all obligations under Sections 4.1, 4.2, 4.3 and 4.4 that accrued
prior to the date of expiration or termination have been satisfied, or in the case of termination by Spero pursuant to Section 9.2.4, until any surviving payment obligations have been satisfied. Articles and Sections 1 (Definitions),
2.2.2, 4.6 (Audit Rights), 5.1 (Ownership of Intellectual Property and Regulatory Documentation), 5.2 (Prosecution and Maintenance of Patent Rights), 6 (Confidentiality), 8 (Indemnification), 9.3 (Effects of Expiration
or Termination), and 10 (Miscellaneous) shall survive and continue in full force and effect after expiration or termination of this Agreement. Except as otherwise provided in this Section 9, all rights and obligations of the Parties
under this Agreement shall terminate upon expiration or termination of this Agreement in its entirety or solely with respect to the terminated country, as the case may be, for any reason. 

9.3.6 Survival of Sublicenses. In the event of a termination of this Agreement by Spero pursuant to Section 9.2.1 or by Meiji
pursuant to Section 9.2.2 or 9.2.3 while a sublicense of rights granted by Spero is in effect, the terms of this Section 9.3.6 shall apply, provided, that, the applicable Sublicensee is not in material breach of the applicable
sublicense agreement. In such event, (a) all of such Sublicensee’s obligations under the applicable sublicense agreement to Spero shall remain in effect as obligations to Meiji and shall be enforceable solely by Meiji as a third party
beneficiary, (b) all of such Sublicensee’s rights against Spero under the sublicense agreement that do not exceed and are not inconsistent with Meiji’s obligations to Spero under this Agreement, whether in scope, duration, nature or
otherwise, shall remain in effect and may be enforced against Spero subject to the terms of the sublicense agreement; provided, that the foregoing shall in no way be interpreted to increase the scope, duration, territory or other aspect of
the rights sublicensed to such Sublicensee and (c) all of Spero’s rights under the sublicense agreement shall remain in effect, may be exercised solely by Meiji as a third party beneficiary and shall inure to the exclusive benefit of
Meiji. For clarity, the termination of this Agreement by Spero pursuant to Section 9.2.2, 9.2.3 or 9.2.4 shall have no effect on any sublicense agreement between Spero or its Affiliates and any Sublicensee, provided that in the event of
termination of this Agreement pursuant to Section 9.2.4, the WLJ Know-How shall be deemed to be excluded from such sublicense agreement. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 33 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 ARTICLE 10 

MISCELLANEOUS 
 10.1
Assignment; Successors. Neither this Agreement nor any right or obligation hereunder may be assigned, in whole or in part, by operation of law or otherwise by any Party without the prior written consent of the other Party, except that either
Party may, without the written consent of the other, assign this Agreement in its entirety (i) to an Affiliate, or (ii) in connection with the transfer or sale of all or substantially all of such Party’s assets or business related to
this Agreement, or in the event of its merger, consolidation or similar transaction, provided that prior written consent of Pfizer Japan to the assignment shall be obtained. In the event that such consent is sought, but not obtained, from Pfizer
Japan, Spero shall have the right to assign all of its rights and delegate its obligations hereunder other than those specifically relating to the WLJ Know-How in connection with such transfer or sale
of all or substantially all of Spero’s assets or business related to this Agreement, or in the event of Spero’s merger, consolidation or similar transaction; provided that if Spero desires to proceed with the assignment of any data set,
report or other document other than those set forth in Exhibit D, Spero shall consult with Meiji whether such data set, report, or other document qualifies as WLJ Know-How or Meiji Know-How and shall abide by Meiji’s determination of such qualification. Subject to the preceding sentence, this Agreement shall be binding upon, inure to the benefit of and be enforceable by, the Parties
hereto and their respective successors and assigns. 
 10.2 Export Control. This Agreement is made subject to any restrictions
concerning the export of products or technical information from the United States or other countries that may be imposed on the Parties from time to time. Each Party agrees that it shall not export, directly or indirectly, any technical information
acquired from the other Party under this Agreement or any products using such technical information to a location or in a manner that at the time of export requires an export license or other governmental approval, without first obtaining the
written consent to do so from the appropriate agency or other governmental entity in accordance with applicable law. 
 10.3 Compliance
with Applicable Laws. In the performance of its obligations hereunder, each Party shall comply and shall cause its Affiliates, employees and contractors involved in the performance of this Agreement to comply with all applicable laws, including
all applicable anti-corruption laws and privacy and data protection laws. 
 10.4 Choice of Law. This Agreement shall be governed by,
and construed in accordance with, the substantive law of the State of New York, regardless of the laws that might otherwise govern under applicable principles of conflict of laws thereof. The UN Convention on the International Sale of Goods is
hereby excluded by the Parties. 
 10.5 Dispute Resolution. 

(a) Scope. Unless otherwise expressly provided for herein, any claim or controversy between the Parties arising out of, or relating to,
the execution, interpretation and performance of this Agreement (including the breach, termination or validity thereof, and the scope and enforceability of this provision) shall be identified in writing and presented to the other Party
(“Dispute Notice”). A Dispute Notice must set forth the details of the dispute and the notifying Party’s position. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 34 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 (b) Settlement Negotiation. Promptly after receipt of a Dispute Notice by a Party, the
Parties shall attempt to resolve the dispute through good faith discussions. 
 (c) Escalation. If the Parties are unable to resolve a
dispute within [***] after receipt of the Dispute Notice by a Party, the Parties shall escalate the dispute to the Spero Executive Officer and the Meiji Executive Officer, each having the authority to resolve the dispute, who shall meet at a
mutually acceptable time and place, and thereafter as often as they reasonably deem necessary, to attempt to resolve the dispute in good faith. 

(d) Arbitration. Any dispute arising out of or relating to this Agreement, including the breach, termination or validity thereof, and
the scope and enforceability of this provision, which cannot be resolved amicably pursuant to Section 10.5(b) and Section 10.5 (c), shall be finally resolved by arbitration in accordance with the arbitration rules of the International
Chamber of Commerce (“ICC”), in effect at the time of the arbitration, except as otherwise mutually agreed by the Parties. Arbitration shall be conducted by a single arbitrator to be agreed upon by the Parties. If the Parties are
unable to agree, the arbitrator shall be appointed in accordance with ICC rules. The arbitrator must have at least ten (10) years of experience in the pharmaceutical industry. The arbitrator shall have the authority to decide the arbitrability
of the dispute and to award fees and expenses, including reasonable attorney’s fees, to a Party. The arbitrator shall not have the authority to award any damages that are expressly limited or excluded by this Agreement. Judgment upon the award
rendered by the arbitrator may be entered by any court having jurisdiction thereof. The arbitration shall be conducted in Singapore in the English language. The arbitration shall be completed and the award issued within [***] of the appointment of
the arbitrator. 
 (e) Confidentiality. The Parties agree that all negotiations for dispute resolution shall be confidential and shall
be treated as compromise and settlement negotiations for purposes of applicable rules of evidence. The Parties further agree that the arbitration shall be kept confidential and that the existence of the arbitration proceeding and any element of it
(including but not limited to any pleadings, briefs or other documents submitted or exchanged, any testimony or other oral submissions, and any awards) shall not be disclosed beyond the arbitration tribunal, the ICC, the Parties, their counsel,
accountants and auditors, insurers and re-insurers, and any person or entity necessary to the conduct of the proceeding. The confidentiality obligations in this Section 10.5(e) shall not apply (i) if
disclosure is required by law, or in judicial or administrative proceedings, or (ii) as far as disclosure is necessary to enforce the rights arising out of the arbitration award. 

10.6 Injunctive Relief. Notwithstanding Section 10.5 (Dispute Resolution) or anything to the contrary in this Agreement, either
Party may seek immediate injunctive or other interim equitable relief as necessary in the event of a breach or threatened breach of a Party’s obligations under Article 5 (Intellectual Property Rights) or Article 6 (Confidentiality) of this
Agreement, or as otherwise may be required in order to prevent imminent irreparable harm, damage or injury to a Party. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 35 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 10.7 Notices. All notices, requests, claims, demands, waivers and other communications
under this Agreement shall be in writing and shall be by registered airmail, postage prepaid, courier services or personal delivery to the following addresses, or to such other addresses as shall be designated from time to time by a Party in
accordance with this Section 10.7. The addresses and other contact information for the Parties are as follows: 
  

			
	If to Meiji:	  	 Meiji Seika Pharma Co., Ltd.
 Attention: Yuji
Sasaki, Managing Executive Officer
 2-4-16, Kyobashi, Chuo-ku
 Tokyo 104-8002, Japan

Tel: [***]

		
	With a copy to:	  	 Meiji Seika Pharma Co., Ltd.
 Attention: Kenshi
Murase, General Manager, Partnering Strategy and Business Development

2-4-16, Kyobashi, Chuo-ku

Tokyo 104-8002, Japan

Tel: [***]

		
	If to Spero:	  	 Spero OpCo, Inc.
 675 Massachusetts Avenue, 14th Floor
 Cambridge, MA 02139, USA

Attention: Ankit Mahadevia
 Tel: 857-242-1600

		
	With a copy to:	  	 Mintz Levin
 Attention: Lewis J. Geffen

One Financial Center
 Boston, MA 02111, USA

Tel: (617) 348-1834

 10.8 Severability. Any term or provision of this Agreement that is invalid or unenforceable in any
situation in any jurisdiction shall not affect the validity or enforceability of the remaining terms and provisions hereof or the validity or enforceability of the offending term or provision in any other situation or in any other jurisdiction. The
Parties shall use all reasonable efforts to replace such invalid or unenforceable provision of this Agreement with a valid and enforceable provision that shall achieve, to the greatest extent possible, the economic, business and other purposes of
such invalid or unenforceable provision. 
 10.9 Integration. This Agreement together with all schedules and exhibits attached hereto,
constitutes the entire agreement between the Parties with respect to the subject matter of this Agreement and supersedes all previous agreements, whether written or oral. Each Party confirms that it is not relying on any representations or
warranties of the other Party except as specifically set forth in this Agreement. 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 36 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 10.10 English Language. This Agreement shall be written and executed in and all other
communications under or in connection with this Agreement shall be in, the English language. Any translation into any other language shall not be an official version thereof, and in the event of any conflict in interpretation between the English
version and such translation, the English version shall control. 
 10.11 Section 365(n). All licenses granted under this Agreement
are deemed to be, for purposes of Section 365(n) of the U.S. Bankruptcy Code, licenses of right to “intellectual property” as defined in Section 101 of such Code. The Parties agree that each Party may fully exercise all of its
rights and elections under the U.S. Bankruptcy Code, regardless of whether either Party files for bankruptcy in the United States. The Parties further agree that, in the event either Party elects to retain its rights under such Code, such Party
shall be entitled to complete access to any technology licensed to it hereunder and all embodiments of such technology. Such embodiments of the technology shall be delivered to the non-bankrupt Party not later
than: (a) the commencement of bankruptcy proceedings against the bankrupt Party, upon written request, unless the bankrupt Party elects to perform its obligations under the Agreement, or (b) if not delivered as set forth above, upon the
rejection of this Agreement by or on behalf of the non-bankrupt Party, upon written request. The Parties acknowledge that the foregoing provisions of this Section 10.11 shall apply only when the
bankruptcy proceedings with respect to either Party are conducted in the United States under the U.S. Bankruptcy Code and shall not apply when the bankruptcy or similar proceedings with respect to either Party are conducted in other jurisdiction
where the mandatory laws governing bankruptcy or similar proceedings in such jurisdiction shall apply. 
 10.12 Waivers and
Amendments. The failure of any 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. No waiver shall be effective unless it has been given in writing and signed by the Party giving such waiver, and no provision of this Agreement may be amended or modified other than by a written document signed
by authorized representatives of each Party. 
 10.13 Independent Contractors; No Agency. Neither Party shall have any responsibility
for the hiring, firing or compensation of the other Party’s or such other Party’s Affiliates’ employees or for any employee benefits with respect thereto. No employee or representative of a Party or its Affiliates shall have any
authority to bind or obligate the other Party for any sum or in any manner whatsoever, or to create or impose any contractual or other liability on such other Party, without such other Party’s written approval. For all purposes, and
notwithstanding any other provision of this Agreement to the contrary, each Party’s legal relationship under this Agreement to the other Party shall be that of independent contractor, and the relationship between the two (2) Parties shall
not constitute a partnership, joint venture, or agency, including for all tax purposes. 
 10.14 Execution in Counterparts; Facsimile
Signatures. This Agreement may be executed in any number of counterparts and by the Parties in separate counterparts, each of which when so executed shall be deemed to be an original and all of which taken together shall constitute one and the
same agreement. This Agreement may be executed by facsimile, pdf or other electronically transmitted signatures and such signatures shall be deemed to bind each Party hereto as if they were the original signatures. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 37 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 10.15 Exclusions and Limitations of Liability. 

10.15.1 SUBJECT TO SECTIONS 10.15.2 AND 10.15.3, NEITHER PARTY NOR ANY OF ITS AFFILIATES SHALL BE LIABLE FOR INDIRECT, INCIDENTAL,
CONSEQUENTIAL, SPECIAL, EXEMPLARY, PUNITIVE OR MULTIPLE DAMAGES ARISING OUT OF THIS AGREEMENT OR THE EXERCISE OF ITS RIGHTS HEREUNDER, OR FOR ANY LOSS OR INJURY TO A PARTY’S OR ITS AFFILIATES’ PROFITS, BUSINESS (INCLUDING BUSINESS
INTERRUPTION) OR GOODWILL ARISING FROM OR RELATING TO ANY BREACH OF THIS AGREEMENT, IN EACH CASE HOWEVER CAUSED AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, TORT, NEGLIGENCE, BREACH OF STATUTORY DUTY OR OTHERWISE, REGARDLESS OF ANY NOTICE OF
SUCH DAMAGES. 
 10.15.2 THE LIMITATIONS AND DISCLAIMERS SET FORTH IN SECTION 10.15.1 SHALL NOT APPLY TO A CLAIM (I) FOR WILLFUL
MISCONDUCT OR GROSS NEGLIGENCE; (II) DAMAGES RESULTING FROM A BREACH OF ARTICLE 6. 
 10.15.3 NOTHING IN THIS SECTION 10.15 IS INTENDED
TO LIMIT OR RESTRICT THE INDEMNIFICATION RIGHTS OR OBLIGATIONS OF EITHER PARTY WITH RESPECT TO THIRD PARTY CLAIMS. 
 10.16 Performance by
Affiliates. To the extent that this Agreement imposes obligations on Affiliates or Sublicensees of a Party, such Party shall cause its Affiliates and shall use diligent efforts to cause its Sublicensees to perform such obligations. Either Party
may use one or more of its Affiliates to perform its obligations and duties hereunder; provided, that each such Affiliate shall be bound by the corresponding obligations of the applicable Party and provided, further, that, subject to such
Party’s assignment to an Affiliate pursuant to Section 10.1, such Party shall remain liable hereunder for the prompt payment and performance of all of its obligations hereunder. 

10.17 Force Majeure. Neither Party shall be liable for failure of or delay in performing obligations set forth in this Agreement, and
neither shall be deemed in breach of its obligations, if such failure or delay is due to natural disasters or any causes beyond the reasonable control of such Party. In event of such force majeure, the Party affected thereby shall use reasonable
efforts to cure or overcome the same and resume performance of its obligations hereunder. 
 10.18 No Third Party Beneficiary Rights.
This Agreement is not intended to and shall not be construed to give any Third Party any interest or rights (including any third party beneficiary rights) with respect to or in connection with any agreement or provision contained herein or
contemplated hereby, other than, to the extent provided in Article 8, the Indemnified Parties. 
 10.19
Non-exclusive Remedy. Except as expressly provided herein, the rights and remedies provided herein are cumulative and each Party retains all remedies at law or in equity, including the Parties’
ability to receive legal damages or equitable relief, with respect to any breach of this Agreement. Neither Party shall be required to terminate this Agreement due to a breach of this Agreement by the other Party. 

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 38 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 10.20 Interpretation. The Article and Section headings used herein are for reference
and convenience only, and will not enter into the interpretation of this Agreement. The word “including” and similar words and phrases mean including without limitation, whether or not expressly stated. The words “herein,”
“hereof” and “hereunder” and other words of similar import refer to this Agreement as a whole and not to any particular Articles or other subdivision. References to the singular include the plural and vice versa.
References to one gender include all genders. References to any law, regulation, statute or statutory provision includes a reference to the law, regulation, statute or statutory provision as from time to time amended, extended or re-enacted. References to “dollars” or “$” are to US dollars, unless otherwise specified. 

10.21 Further Assurances. Each Party agrees to execute, acknowledge and deliver such further instructions, and to do all such other
acts, as may be reasonably necessary or appropriate in order to carry out the purposes and intent of this Agreement. 
 10.22
Construction. The Parties hereto acknowledge and agree that: (a) each Party and its counsel reviewed and negotiated the terms and provisions of this Agreement and have contributed to its revision; (b) the rule of construction to the
effect that any ambiguities are resolved against the drafting Party shall not be employed in the interpretation of this Agreement; and (c) the terms and provisions of this Agreement shall be construed fairly as to all Parties hereto and not in
favor of or against any Party, regardless of which Party was generally responsible for the preparation of this Agreement. 
 10.23 Records
Generally. Without limiting any of the Party’s obligations set forth in any other provision of this Agreement, each Party shall keep or shall cause its Affiliates to keep records as are appropriate to document such Party’s, and its
Affiliates’, compliance with its obligations hereunder and under applicable law in a manner consistent with this Agreement for those periods applicable to such records in accordance with applicable law. 

10.24 Press Releases and Publicity. 

10.24.1 Each Party may issue a press release at a time reasonably acceptable to the Parties. 

10.24.2 Each Party shall be free to make public disclosures concerning its own activities and the results of the Development and
Commercialization of the Compound and the Product in its respective Territory so long as (i) such Party shall comply with its confidentiality obligations set forth in Article 6 (Confidentiality) and (ii) such Party complies with
Section 10.24.3, and in Spero’s case, Section 10.24.4. 
 10.24.3 If either Party wishes to make any public disclosure
concerning its own activities and the results of the Development and Commercialization of the Compound and the Product in its respective Territory, it shall first notify the other Party of such planned press release or public announcement, including
any oral presentation or abstract, and provide a draft for review no less than [***] in advance of issuing such press release or making such public announcement 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 39 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 (or, with respect to press releases and public announcements that are required by applicable laws, with as
much advance notice as possible under the circumstances if it is not possible to provide notice no less than [***] in advance). Each Party shall have the right to review and approve any such planned press release or public announcement proposed by
the other Party that contains clinical data or pertains to results of clinical studies or other studies with respect to the Compound and/or the Product, or that includes Confidential Information of the other Party; provided, however, that
(a) the reviewing Party shall attempt to provide such approval as soon as reasonably possible and will not unreasonably withhold such approval; (b) the reviewing Party shall provide explanations of its disapproval of such press release or
public announcement; and (c) a Party desiring to make such press release or public announcement may issue such press release or public announcement without such prior review by the other Party if (i) the entire contents of such press
release or public announcement have previously been made public other than through a breach of this Agreement by such Party, and (ii) such press release or public announcement does not materially differ from a previously issued press release or
other publicly available information; and provided, further, that the other Party shall have the right to review, but not approve, any press release or public announcement that the proposing Party determines is required by applicable laws based on
the advice of counsel. The Party reviewing a press release or public announcement provided under this Section 10.24.3 shall review and approve or disapprove such press release or public announcement within [***] after its receipt thereof. 

10.24.4 Spero acknowledges that the [***] in connection with the WLJ Agreement provides Pfizer Japan certain review rights that may extend to
public announcements that Spero wishes to make concerning its Development and Commercialization of the Compound and the Product. Spero agrees that Meiji may disclose to Pfizer Japan the proposed public announcements disclosed by Spero to Meiji
pursuant to Section 10.24.3, solely during such time that Pfizer Japan’s review rights under the [***] remain in effect. Meiji agrees to use its Commercially Reasonable Efforts to submit Spero’s proposed public disclosures to Pfizer
Japan in a timely manner to meet Meiji’s obligations under the [***] and to incorporate any comments from Pfizer Japan into Meiji’s comments pursuant to Section 10.24.3, consistent with the timeframes set forth in
Section 10.24.3. In no event shall this Section 10.24.4 prevent Spero from timely making any public disclosure that Spero has determined is required by applicable laws based on the advice of counsel. 

[Remainder of this page intentionally blank.] 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  
 40 

 CONFIDENTIAL TREATMENT REQUESTED 

 

 IN WITNESS WHEREOF, each Party has caused this Agreement to be duly executed by its authorized representative
under seal, in duplicate on the Effective Date. 
  

	
	SPERO OPCO, INC.
	
	 /s/ Ankit Mahadevia

	
	Name: Ankit Mahadevia
	Title: Chief Executive Officer
	
	MEIJI SEIKA PHARMA CO., LTD.
	
	 /s/ Daikichiro Kobayashi

	
	Name: Daikichiro Kobayashi
	Title: President and Representative Director

  
 Portions of this Exhibit,
indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities
Act of 1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 EXHIBIT A 

Key Terms of Clinical Supply Agreement 
  

	 	•	 	Form of Product for clinical use: [***] and meeting the specifications agreed upon by the Parties (the “CTM”). 

  

	 	•	 	Quantity: a quantity of [***] to be specified in the Clinical Supply Agreement for delivery at the Supply Price by [***]. The quantity and supply date shall be [***]. 

 

	 	•	 	Meiji shall [***], and Spero shall [***]. 

  

	 	•	 	Spero shall, [***] for Meiji to [***]; provided, however, that both Parties may renegotiate the [***] after reasonable [***]. 

  

	 	•	 	Supply Price: [***] 

  

	 	•	 	If Spero decides to [***], Spero shall[***]. 

  

	 	•	 	Spero shall own all Intellectual Property generated by Meiji or its contractors under the Clinical Supply Agreement, excluding any Intellectual Property generated solely by Meiji or its contractors that is generated
without the use of the Meiji Intellectual Property, Spero Intellectual Property or Jointly-Generated Intellectual Property, and Meiji shall make all assignments necessary to perfect Spero’s rights in such new Intellectual Property.

  
 Portions of this Exhibit, indicated by the mark
“[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as
amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 EXHIBIT B 

Compound 
 [***] 

[***] 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 EXHIBIT C 

Selected Items of WLJ Know-How 

1. [***] 
 (1) [***] 

 

					
	Study No.	  	[***]	  	Title of the Study Report
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]

 (2) [***] 
  

					
	 Study No.
	  	[***]	  	 Title of the Study Report

	 —  
	  	—  	  	[***]

 (3) [***] Studies 
  

					
	Study No.	  	[***]	  	Title of the Study Report
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

					
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

					
	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

 
 Portions of this Exhibit, indicated by the mark “[***],”
were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

					
	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

 2. [***] Studies 
 (1)
[***] 
  

					
	Study No.	  	[***]	  	Title of the Study Report
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  		  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

					
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]

 (2) [***] 
  

					
	 Study No.
	  	[***]	  	 Title of the Study Report

	 [***]
	  	—  	  	 [***]

 (3) [***] Studies [***] 
  

					
	Study No.	  	[***]	  	Title of the Study Report
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

					
	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

 (3) [***] Studies [***] 
  

					
	 Study No.
	  	[***]	  	 Title of the Study Report

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

	 [***]
	  	—  	  	 [***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

					
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  		  	[***]
	[***]	  	—  	  	[***]

 (5) [***] Studies 
  

					
	Study No.	  	[***]	  	Title of the Study Report
		  		  	
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  		  	[***]

 (6) [***] Studies 
  

					
	Study No.	  	[***]	  	Title of the Study Report
		  		  	
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

					
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	[***]	  	—  	  	[***]
	—  	  	—  	  	[***]

 3. [***] Studies 
  

					
	Study No.	  	[***]	  	Title of the Study Report
	—  	  	[***]	  	[***]
	—  	  	[***]	  	[***]
	—  	  	[***]	  	[***]
	—  	  	[***]	  	[***]
	—  	  	[***]	  	[***]
	—  	  	[***]	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 EXHIBIT D 

Selected Items of Meiji Know-How 

 

			
	Study No.	  	Title of the Study Report
	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

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

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

			
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***] Studies
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

			
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***] Studies

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

			
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***] Studies
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
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	[***]	  	[***]
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	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***] Studies
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

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

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

			
	[***]	  	[***]
	[***]	  	[***]
	[***] Studies
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]
	[***]	  	[***]

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 EXHIBIT E 

Pfizer Letter 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 Meiji Seika Pharma Co., Ltd. 

2-4-16, Kyobashi,
Chuo-ku, Tokyo, 104-8002 Japan 
 Tel: [***] / Fax: [***] 

9 January 2016 
 Pfizer Japan Inc. 

3-22-7, Yoyogi, 

Shibuya-ku, 
 Tokyo, 151-8589 
 Japan 

Re: Carbapenem/Tebipenem and Spero Therapeutics 

Ladies and Gentlemen: 
 We refer to that certain
License Agreement (the “Wyeth Agreement”) dated as of the [***] day of [***], between Meiji Seika Pharma Co., Ltd. (“Meiji”) and Pfizer Japan Inc., as successor to Wyeth Lederle Japan, Ltd. (“Pfizer
Japan”), currently a wholly-owned subsidiary of Pfizer Inc. (“Pfizer”). 
 The capitalized terms used in this
letter and not otherwise defined in this letter have the meanings given in the Wyeth Agreement. 
 Meiji is contemplating entering into an
agreement with Spero Therapeutics LLC (together with its affiliates, “Spero”) pursuant to which, among other things, Meiji would supply the Compound and the API to Spero, help develop the Product for Spero and supply the Product to
Spero, and otherwise assist Spero with the transfer or license of the WLJ Know How and MS Know How outside the Territory (such development of the Product, supply of the Compound, the API and/or the Product and transfer or license of the WLJ Know
Know and the MS Know How outside the Territory being the “Transaction”). 
 [***]. 

[***] with Spero, we are seeking your consent to our proposed Transaction with Spero, [***] to (i) supply the Compound and the API to
Spero, (ii) help develop the Product for Spero, (iii) supply the Product to Spero and (iv) assist Spero with the transfer or license of the WLJ Know How and MS Know How outside the Territory. 

By executing and returning a signed copy of this letter, you hereby agree and consent to our proposed Transaction with Spero and [***] in the
foregoing paragraph. This letter supersedes all prior written agreements between the parties with respect to the subject matter hereof. 
  

	
	 Sincerely,

	 Meiji Seika Pharma Co., Ltd.

	
	
By: /s/ Yuji Sasaki             
                                         
          

	 Name: Yuji Sasaki

	
Title: Managing Executive Officer, Member of the 
Board

  

	
	 Agreed and Accepted as of the date written above:

	
	 Pfizer Japan Inc.

	
	 By:
[Seal]                                        
              

	 Name: Ichiro Umeda

	Title: President and Representative Director

  
 Portions of this Exhibit, indicated
by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of
1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 ADDENDUM TO LICENSE AGREEMENT 

This Addendum (this “Addendum”) is made and effective as of the 14th day of June, 2017 (the “Effective
Date”) by and between Meiji Seika Pharma Co., Ltd., a Japanese corporation with offices at 2-4-16, Kyobashi, Chuo-ku, Tokyo,
104-8002 Japan (“Meiji”) and Spero OpCo, Inc., a Delaware corporation with offices at 675 Massachusetts Avenue, 14th Floor, Cambridge, MA 20139, USA (“Spero”). 

INTRODUCTION 

WHEREAS, Meiji and Spero entered into a License Agreement dated June 14, 2017 (the “License Agreement”) pursuant to
which Meiji has granted to Spero an exclusive license to use Meiji Intellectual Property, Meiji Regulatory Documentation and WLJ Know-How for the Development, Manufacture and Commercialization of the Compound
and the Product in the Field in the Spero Territory; and 
 WHEREAS, in addition to the license granted under the License Agreement, Spero
desires to be granted further by Meiji a license to use Meiji Intellectual Property, Meiji Regulatory Documentation and WLJ Know-How for the Development and Manufacture of the Compound and the Product in the
Field in the Meiji Territory solely for the purpose of furthering Development, Manufacture and Commercialization of the Compound and/or the Product in the Field in the Spero Territory, and Meiji desires to grant such a license to Spero, subject to
the terms and conditions set forth herein. 
 NOW, THEREFORE, for and in consideration of the mutual covenants contained herein, Meiji and
Spero hereby agree as follows: 
 1. Definitions. All the capitalized terms used and not otherwise defined in this Addendum shall have the same
meanings as ascribed to them in the License Agreement. 
 2. License Grant. Subject to the terms and conditions of this Addendum, Meiji hereby grants
to Spero, under the Meiji Intellectual Property, Meiji Regulatory Documentation and WLJ Know-How, a non-exclusive right and license, with the right to sublicense subject
to the same conditions as set forth in Section 2.4.1 of the License Agreement, to Develop and Manufacture the Compound and the Product in the Field in the Meiji Territory solely for the purpose of furthering Development, Manufacture and
Commercialization of the Compound and/or the Product in the Field in the Spero Territory. Without limiting the foregoing, Spero hereby agrees to Commercialize the Product solely in the Spero Territory and shall not, and shall not permit its
Affiliates, Sublicensees or distributors to, distribute market, promote, offer for sale or sell the Product (a) to any Third Party outside the Spero Territory or (b) to any Third Party inside the Spero Territory that Spero, or its
Affiliates, Sublicensees or distributors, as applicable, knows is reasonably likely to distribute, market, promote, offer for sale or sell such Product outside the Spero Territory. 

3. Financial Terms. In consideration of the right and license granted by Meiji to Spero under Section 2 above, within [***] of the Effective Date,
Spero shall pay to Meiji a one-time, non-refundable, non-creditable upfront fee of one hundred thousand US dollars ($100,000 USD). The Parties acknowledge that the
upfront payment, Milestone Payments, Royalties and Licensee 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 
Revenue Share set forth in Article 4 of the License Agreement shall be the consideration for the rights and licenses granted by Meiji to Spero under the License Agreement without this Addendum
and shall not be the consideration for the right and license granted by Meiji to Spero under Section 2 above. 
 4. Term and Termination. 

4.1 Unless terminated earlier pursuant to Section 4.2 below, this Addendum shall become effective as of the Effective Date and shall
terminate upon the expiration of the Term or termination of the License Agreement in its entirety. 
 4.2 In the event of any material breach
of this Addendum by either Party, the other Party may terminate this Addendum pursuant to the same procedures as set forth in Section 9.2.2 of the License Agreement. 

5. Effect of Termination on License. 
 5.1
In the event of termination of this Addendum due to the expiration of the Term of the License Agreement in its entirety in accordance with Section 9.1 thereof, the right and license granted by Meiji to Spero under Section 2 above shall
survive and become fully paid-up and perpetual. 
 5.2 In the event of any termination of this
Addendum by Meiji under Section 4.2 above or due to the termination of the License Agreement by Spero under Section 9.2.1 thereof or by Meiji under Section 9.2.2 or 9.2.3 thereof, the right and license granted by Meiji to Spero under
Section 2 above shall immediately terminate. 
 5.3 In the event of any termination of this Addendum by Spero under Section 4.2
above or due to the termination of the License Agreement by Spero under Section 9.2.2 or 9.2.3 thereof, the right and license granted by Meiji to Spero under Section 2 above shall survive and become fully
paid-up and perpetual. 
 5.4 In the event of any termination of this Addendum due to the termination
of the License Agreement by Spero under Section 9.2.4 thereof, the right and license granted by Meiji to Spero under Section 2 above shall survive and become fully paid-up and perpetual but be
limited to exclude the WLJ Know-How. 
 6. Other Conditions. Unless this Addendum is terminated prior to the
expiration of the Term or termination of the License Agreement in its entirety, this Addendum constitutes a part of the License Agreement and all applicable terms and conditions of the License Agreement shall apply to this Addendum. 

[Remainder of this page intentionally blank] 
  

Portions of this Exhibit, indicated by the mark “[***],” were omitted and have been filed separately with the Securities and
Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities Act of 1933, as amended. 

  

 CONFIDENTIAL TREATMENT REQUESTED 

 

 IN WITNESS WHEREOF, each Party has caused this Addendum to be duly executed by its authorized
representative under seal, in duplicate on the Effective Date. 
  

	
	SPERO OPCO, INC.
	
	 /s/ Ankit Mahadevia

	Name: Ankit Mahadevia
	Title: Chief Executive Officer
	
	MEIJI SEIKA PHARMA CO., LTD
	
	 /s/ Daikichiro Kobayashi

	Name: Daikichiro Kobayashi
	Title: President and Representative Director

  
 Portions of this Exhibit,
indicated by the mark “[***],” were omitted and have been filed separately with the Securities and Exchange Commission pursuant to the Registrant’s application requesting confidential treatment pursuant to Rule 406 of the Securities
Act of 1933, as amended.

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