Document:

EX-10.17

 Exhibit 10.17 
  

					
	 Calculation of charges
 by Marxbox Bauprojekt
[Development] GmbH & Co. OG
 Percentage fee: 6,315.71

Date of the calculation: 12/16/2010
	  		  	 DUPLICATE

 Vienna, on 12/16/2010 
 Marxbox
Bauprojekt GmbH & Co. OG 
 LEASE AGREEMENT 

Entered into by 
 Marxbox Bauprojekt
GmbH & Co. OG 
 domiciled in Vienna 

(FN 346428 d Commercial Court Vienna) 

1021 Vienna, Messeplatz 1 
 referred to in the
following as the Landlord, on the one hand, 
 and 

ARSANIS Biosciences GmbH 

domiciled in Vienna 
 (FN 354305
m Commercial Court Vienna) 
 Westbahnstrasse 32-34/1/12 

1070 Vienna 
 referred to in the following as
the Tenant, on the other hand, 
 as follows: 

Preamble 
 The Landlord is
the sole owner of the property EZ 4359 Land Register 01006 Landstraße, District Court Inner City Vienna, consisting of Lot No. 1449/3. 
 With
the notice of 02/18/2009, Number MA 37-BB/48393-1/2008, the Magistrate of the City of Vienna, Municipal Department 37, Building Inspection, issued the building permit
for the 
  

			
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 construction of a seven story
laboratory and office building with two basement levels in massive construction on the above-named project property (referred to in the following as building permit); this notice (Attachment ./1) has become final and absolute. The building is
a new construction being built by the Landlord without the aid of public funds. The location of the building can be seen in the site plan (Attachment ./2). 

The Tenant therefore takes note that the rental property is situated in a building that has been newly constructed without the aid of public funds on
the basis of a building permit issued after 06/30/1953, so that by act of law only the provisions of §§ 14, 16b, 29 to 36, 45, 46 and 49, but not the other provisions of Sections I and II of the Tenancy Law 1981 as amended, referred to in
the following as MRG (Mietrechtsgesetz [Tenancy Law]), apply to the Lease Agreement. 
 Therefore, with respect to the thus not expressly legally
regulated areas of the Lease Agreement, only the provisions of the Lease Agreement, or subsidiarily those of the Austrian General Civil Code (Allgemein Bürgerliches Gesetzbuch ABGB), are binding for the contracting parties; the referral
to individual provisions of the MRG does not mean that the MRG would become applicable to a greater extent beyond these expressly named, individual provisions of the MRG, or as whole. 

I. Rental Property 
  

	1.	The Landlord leases to the Tenant and the latter leases from the former the part of the 3rd upper floor that is marked in red in the contract plans
(Attachment ./3) of the building 1030 Vienna, Helmut Qualtinger Gasse 2, being constructed on the property EZ 4359 Land Register 01006 Landstraße, District Court Inner City Vienna, with a dimension of ca. 698.10 m2, a storage bay on the 2nd basement level with a dimension of ca. 25 m2, and five garage
parking spaces on the 1st basement level allocated by the Landlord (referred to together in the following as rental property). 

 

	2.	The stated dimensions are preliminary; the actual dimension, upon which the final calculation of the rent will be based, will be determined from the as-completed drawings
submitted to the building authority after completion of the rental property. 

  

	3.	 The obligations of the Landlord concerning the construction of the rental property while taking
into account the official regulations applicable at the time of the building permit are finalized in the attached contract plans (Attachment ./3), which constitute an integral component of the Lease Agreement, or in the building and interior
description (Attachment ./4), whereby fitments and/or systems, equipment and devices possibly included in Attachment ./3 - that are not also expressly named in the building and interior description (Attachment ./4) - have a purely
illustrative character and do not create an obligation for the Landlord to provide the same. All changes or adaptations, systems, equipment and devices 

  
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 needed for the
operation of the rental property shall be performed or procured by the Tenant. The Landlord does, however, guarantee that the rental property is suitable from a structural perspective for obtaining an operational plant permit
for operating a biotechnology laboratory. 
  

	4.	The Landlord reserves the right to change or deviate from the aforementioned Attachments ./2 to ./4, if the change or deviation is minor, represents only a slight disadvantage for the Tenant and is
objectively justified, such as in particular 

  

	 	•	 	changes or deviations based on legal or official regulations, orders or requirements, 

  

	 	•	 	changes or deviations based on static or technical requirements or structural necessity, 

  

	 	•	 	changes or deviations based on the selection of equivalent or higher quality materials, equipment, devices and the like as a result of lack of availability, technical incompatibility and the like. 

 

	5.	The Tenant gives his explicit consent to such changes. The Landlord will take specific change requests of the Tenant (e.g. moving partition walls and architectural details), which do not require
appreciable additional cost nor cause a major delay, into account as far as appropriate and possible; the relevant details are clarified with the Landlord’s architect and recorded in an addendum to the building and interior description.

  

	6.	Only the interior space of the rental property is being leased, not its exterior surfaces and not the shared use parts and other general parts of the building. 

 

	7.	The Tenant has the right, 

  

	 	a)	to place advertising or signs with his company name in the entrance area of the building in which the rental property is situated, at the locations designated for this purpose, and on the entrance door of the
rental property, and 

  

	 	b)	to place an advertisement with the company logo “ARSANIS” on a side wall of the building in which the rental property is situated, facing the T-Center,

 for the duration of the tenancy (insofar as not otherwise specified at his own expense and risk), specifically upon prior
written approval of the Landlord and in consultation with the architect, Municipal Departments 19 and 37 and the existence of all official permits (including the utilization tax) required for this purpose - to be applied for and obtained by
the Tenant at his expense and risk (possibly also to be revoked at any time). The Landlord will deny approval only for important, objective reasons, such as for example a negative effect on the overall impression of the building. 

  
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 The initial
construction of a substructure for the advertisement to be placed on a side wall of the building in which the rental property is situated, facing the T-Center, is carried out by the Landlord and
at his expense within two months after all official permits required for this purpose have been provided; all other structures, in particular the light box for the advertisement, are erected by the Tenant at his own expense and risk. 

 

	8.	The Tenant acknowledges with approval that, even after transfer of the rental property, work may be performed in other properties and/or on general parts of the building and may cause disturbances
resulting from noise or dirt. The Tenant acknowledges these impairments to use associated with construction work, for example resulting from noise and/or dirt, as long as these impairments do not prevent or seriously disrupt access to and provision
of the rental property or use, i.e. the Tenant accepts the impairments typically associated with such a construction site. 

II. Term of Lease 
  

	1.	The tenancy starts with the transfer of the rental property (the transfer of the office spaces takes place within three months of the plan approval by the Tenant, which is, however, to occur no later than
12/15/2010; the transfer of the laboratory spaces takes place within four months of the plan approval by the Tenant, which is, however, to occur no later than 01/15/2011) and is finalized for an indefinite period. 

 

	2.	After signing this Lease Agreement, the Tenant waives the right to terminate this Lease Agreement with statutory notice prior to a termination date of 04/30/2021. The Landlord accepts this waiver of
termination. 

  

	3.	In the event that the Tenant does not terminate this Lease Agreement with statutory notice prior to 04/30/2021, the waiver of termination will be extended without further declaration for one more year. The
Landlord accepts this waiver of termination as well. 

 III. Transfer and Acceptance of the Rental Property

  

	1.	The transfer and acceptance of the rental property takes place as follows: with respect to the office spaces within three months of the plan approval; with respect to the laboratory spaces within four months of
the plan approval. The obligation of the Tenant to pay the agreed upon rent, for the entire rental property, starts on the first of the month following the transfer of the office spaces. 

  
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	2.	Deficiencies that impede the further adaptation or use of the rental property only insignificantly have no effect on the obligation to accept the rental property and the payment of rent. A withdrawal of
the Tenant from the contract requires a delay, for which the Landlord is responsible, of the transfer of the office spaces by at least six weeks or the transfer of the laboratory spaces by at least eight weeks. 

 

	3.	The transfer of the rental property to the Tenant always requires the prior transfer of the bank guarantee in accordance with Item XV to the Landlord; the transfer of the bank guarantee is, however,
already stipulated at the time of signing this Lease Agreement. 

 IV. Rent 

 

	1.	The monthly rent consists of the base rent, the ancillary charges and the respective value added tax to be paid on the base rent and the ancillary charges. 

 

	2.	Base rent: 

 i.)    Spaces on the 3rd upper floor 
 The freely negotiated monthly base rent is €17.00/m2 (excl. VAT) with a useable area of ca. 698.10 m2. 

ii.)    Garage parking spaces 

The freely negotiated monthly base rent is €98.50 (excl. VAT) per parking space. 

iii.)    Storage bay in the basement 

The freely negotiated monthly base rent is €6.50/m2 (excl. VAT) with a useable area
of ca. 25 m2. 
 Useable area in the sense of this Lease Agreement is the entire floor
space of the rental property (without subtracting partition walls). Load-bearing walls, supports and general building service ducts as well as stairwell spaces are not counted as useable area. 

The final determination of the useable area is carried out on the basis of the as-completed drawings
submitted to the building authority available at transfer; each of the contracting parties reserves the right to determine the actual measurements, which will then be used. 

  
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	3.	Ancillary charges 

 The ancillary charges to be borne proportionately by the
Tenant include all taxes, fees and charges relating to the property and the building mandated to the Landlord by law, regulation or official order, all operating costs in accordance with the list in §§ 21 ff. MRG as well as
(regarding both content and amount) in particular the following expenses, insofar as they are not to be borne directly by the respective tenants: 
  

	 	•	 	the costs of liability, fire, storm damage, glass breakage, machine failure and water pipe damage insurance and other property insurance at the reinstatement value; 

 

	 	•	 	the expense of operation, care, upkeep, maintenance, repair, preservation and cleaning of the building (with the exception of the interior of rental properties) and the associated spaces, equipment and systems such as
in particular the building equipment and systems for heating, ventilation, cooling, sanitation, elevators, fire protection, supply of power, water and media services, machines and the like, corridors, sluices, stairwells, exterior walls, exterior
windows, roofs, technical rooms, trash rooms, lightning protection systems and green spaces, access paths, other common areas, etc.; 

  

	 	•	 	the water and wastewater fees, the costs of chimney sweeping, sewer clearing, trash and refuse collection, pest control, waste disposal, sidewalk and street cleaning, snow removal and spreading, the costs of electricity
for lights and power, irrigation and drainage, etc.; 

  

	 	•	 	the expense of security, if any, for the building and the associated spaces, equipment and systems during the day and during the night, and the usual costs for professional management of the property and the building.

 Within the context of economic viability, the Landlord or the building management reserves the right to hire
personnel or commission third parties to perform the work or the services. 
 Therefore, according to the will of the contracting parties,
all expenses incurred for the operation, care, upkeep, maintenance, repair, preservation and cleaning, as well as the management of the property, the building and the associated spaces, equipment and systems are included in the ancillary charges.

 The fact that the Tenant does not make use of common systems does not release him from the obligation to pay a proportionate share
of the expenses. 

  
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 Until further
assessment by the Landlord, the monthly advance payment of ancillary charges is €2.90 per m2. 

The Landlord has the right to increase and, in mutatis mutandis application of § 21 Par. 3 MRG, annually adapt the monthly advance
payment of ancillary charges to the actual amount of the expenses incurred. 
 An annual lump sum accounting of the ancillary costs in
mutatis mutandis application of § 21 Par. 3 MRG shall be understood as agreed upon. Should the annual accounting result in a surplus in the Tenant’s favor, the Landlord shall apply this surplus amount to the next assessment
or to any arrears owed by the Tenant; the Tenant shall make any additional payments no later than two weeks after the Landlord’s assessment. 
  

	4.	Apportionment of ancillary charges: 

 The share of the ancillary charges to be borne by
the Tenant is generally determined by the proportion of the useable area of the rental property (to be calculated in the sense of this Lease Agreement) to the useable area of all rental properties in the building. 

To the extent that individual consumption measurement devices for individual ancillary charges are in place, the tenant is obligated to
pay the incurred costs (incl. energy costs, expenses for operation, care, upkeep and cleaning, etc.) based on the measured consumption for the rental property per se, or by apportionment to the respective rental property based on the
share of consumption. Included are in particular 
  

	 	•	 	the costs for heating, cooling and (cold) water (including wastewater that does not require treatment); this consumption is measured per rental unit by means of submeters; it is noted that the rental property
will be connected to the district heating network; 

  

	 	•	 	the costs of ventilation (incoming air and exhaust air); these are calculated proportionately according to the ratio of incoming air to the rental property to the overall quantity of incoming air (air adjustment
key). 

 The operating expenses for the rental property itself and the cost of operating material, in particular the
power and telephone costs, server cooling and additional cooling, otherwise needed by the Tenant to conduct business are borne by the Tenant. The same applies to the purchase of electricity procurement rights. 

Insofar as, for certain expenditures for the rental property, for example for power, telecommunication (telephone, internet access,
etc.), other media (TV, Telekabel [Austrian cable and internet provider], etc.), hazardous waste and special materials (e.g. nitrogen, oxygen), each including connection costs as well as operation, care, upkeep, maintenance,

  
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 repair,
preservation and cleaning of the installations and systems, it is possible to contract and settle charges directly with the respective provider and/or other company, the Tenant commits himself to participate, to the greatest extent possible,
in concluding an appropriate contract with the provider and/or other company and to settle charges directly with it. 
  

	5.	Value Added Tax: 

 The Landlord opts for the obligation to pay taxes in accordance
with § 6 Par. 2 UStG (Umsatzsteuergesetz [Valued Added Tax Act]). The Tenant declares himself in agreement with the exercising of this option. The value added tax payable on the rent and (proportionate) operating and ancillary
charges at the appropriate statutory rate will therefore additionally be charged to the Tenant. 
 V. Rent Due Date 

 

	1.	The monthly rent including all taxes, fees, ancillary costs, value added tax, etc. is due for payment in advance on the first of every month with a five-day grace period -
independent of any assessment by the Landlord - and shall be paid to the account designated by the Landlord free of charges or deductions in such a way that the rent is received no later than on the due date. 

 

	2.	The Tenant shall bear the risk for the timeliness of the rent payment. 

  

	3.	Communications from the Tenant on payment receipts have no legal consequences. The Tenant acknowledges that such communications cannot be deemed to have been tacitly taken note of by the Landlord.

  

	4.	In the event that the Tenant is in arrears with the rent or other monetary claims of the Landlord arising out of this Lease Agreement, interest on arrears at the rate of 5% above the current base interest
rate of the European Central Bank as agreed upon shall apply; however, the Landlord reserves the right to charge higher interest on arrears from the title of the payment of damages. 

VI. Indexation 
  

	1.	The agreed upon base rent is adjusted by linking to the Consumer Price Index 2005 announced by Statistik Austria [Austrian Statistical Office] or the successor index replacing it. In the event that no successor index is
announced, the adjustment shall be calculated in such a way that it corresponds to the decrease/increase of the general purchasing power. The starting point for the adjustment is the index number announced for the month of the acceptance of the
rental property. 

  
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	2.	The agreed upon base rent changes to the same extent that the named index changes with respect to the starting point. The base rent is adjusted once a year in January with effect for that current year. The new
applicable index number becomes the new starting point. The increase/decrease of the base rent on the basis of the indexation not occurring directly after the corresponding increase in the index does not constitute a conclusive waiver of any
increase/decrease. 

 VII. Obligations of Care, Upkeep and Maintenance 

 

	1.	A handover protocol, in which any obvious deficiencies are to be recorded, shall be filled out upon transfer of the rental property; any deficiencies not apparent at the time of transfer shall be reported in
writing within 14 days after being identified. Identified deficiencies shall be rectified by the Landlord within a reasonable period of time. 

  

	2.	The Tenant commits himself to continually take care of the rental property, including its equipment and systems such as, e.g. the lighting, ventilation and water supply systems, and the heating and
sanitary systems (as far as any of these are available), at his own expense after the transfer, have it verifiably serviced and maintained regularly by authorized tradesmen and rectify any damage immediately in such a way that the condition existing
at the time of transfer is maintained and, accounting for normal wear and tear, the rental property is returned to the Landlord after the termination of the tenancy in the condition in which it was originally transferred to the
Tenant. The Tenant acknowledges with approval that, due to laid cooling hoses and conduits in all concrete and screed elements in the rental property (in particularly in floors and ceilings), holes can be drilled after separate
consultation with building services. Damage that can be attributed to obvious or hidden construction defects are not to be rectified by the Tenant. 

  

	3.	The Tenant therefore does not require the Landlord to maintain the interior of the rental property in accordance with § 1096 ABGB; the interior of the rental property comprises the
entire useable area of the rental property in the sense of this Lease Agreement (including power and water conduits as well as ventilation ducts in dividing walls and in the raised floor, EDP cabling, surfaces such as walls and floors, sanitary
facilities, kitchen). 

  

	4.	In the event of serious damage to the building, the Tenant commits himself to notify the Landlord of this immediately in writing. 

 

	5.	If the Tenant does not fulfil his obligations with respect to care, upkeep and stipulated maintenance as well as damage repair, the Landlord can perform the required work himself, or have it performed, at
the Tenant’s risk and expense. 

  
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	6.	The Tenant shall be liable to the Landlord without limit for all damages and expenses incurred by the Landlord or third parties as a result of handling of the rental property or common parts
of the building that is inappropriate or otherwise in violation of the agreement, or insufficient care, upkeep and stipulated maintenance by the Tenant, his employees, agents, visitors and generally all persons who can be associated with the
Tenant in any way. 

 VIII. Changes to the Rental Property  

 

	1.	Structural modifications of any kind to the rental property are to be announced by the Tenant in advance in writing and require the prior express written approval of the Landlord. This
applies in particular to structural modifications in the form of special requests made known to the Landlord by the Tenant prior to transfer of the rental property and are consequently carried out in coordination with the
Landlord. The work may be performed only by officially authorized tradesmen. The announcement to the Landlord shall include a detailed declaration of the type and extent of the intended work and the name of the prospective authorized
tradesman. The Tenant shall, at his own expense and risk, ensure that any official permits are obtained in a timely manner and all relevant legal and official regulations, orders and provisions are fulfilled, as well as indemnify and hold the
Landlord harmless with respect to any kind of injury. 

  

	2.	In the event that the Tenant makes changes without the express written approval of the Landlord, the Landlord has the right to demand the immediate restoration of the original condition at the
expense of the Tenant, even with the continued existence of the Lease Agreement. 

  

	3.	In each case the Tenant shall bear all expenses connected with a modification of the rental property himself as well as indemnify and hold the Landlord harmless with respect to any expenses,
damages, etc. The provisions of § 1097 second sentence ABGB are, insofar as these provisions refer to § 1037 ABGB, expressly waived. 

  

	4.	If the Landlord has granted his express written approval to a structural modification, he cannot demand the restoration of the original condition upon termination of the Lease Agreement. Any investments connected
to the rental property shall be transferred to the ownership of the Landlord without claim for cost reimbursement, whereby the Tenant waives the assertion of claims for compensation, under any title whatsoever. 

IX. Limitations of Liability / Obligations to Tolerate 

  
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	1.	From impairments to the usability of the rental property, in particular by any disruptions or shut-offs of the water or energy supply, or in the case of defects or disruptions of the heating or cooling, the
power, light, water and sewerage equipment or the like, the Tenant shall derive legal claims with respect to the compensation for damages only in the case of deliberate or grossly negligent causation on the part of the Landlord.

  

	2.	Any liability of the Landlord for damages of any kind is expressly limited to intentional wrongdoing and gross negligence. 

  

	3.	The Landlord reserves the right to construct additions and extensions of any kind, as well as relocate, completely remove or use existing installations (not however the property that is the subject matter of the
contract) for other purposes. The usability of the rental property may not be restricted by this activity. 

  

	4.	The Tenant shall allow the temporary use and modification of the rental property, if and insofar as such an encroachment in the tenancy law is absolutely necessary for the performance of preservation,
renovation, damage repair or improvement work to the general parts of the building or in another rental property. 

  

	5.	The Landlord informs the Tenant that new construction, additional construction or renovation work is planned on the property that is the subject matter of the contract, or on the property adjacent to it,
not only concerning the rental property, but also concerning adjacent building complexes. The Tenant acknowledges these impairments to use associated with construction work, for example resulting from noise and/or dirt, as long as these
impairments do not prevent or very seriously disrupt access to and provision of the rental property or use, i.e. the Tenant accepts the impairments typically associated with such a construction site. 

X. Entering the Rental Property 
  

	1.	After advance notification and at reasonable intervals, the Landlord and persons authorized by him have the right to enter the rental property for objective reasons during the Tenant’s business
hours. 

  

	2.	In case of imminent danger, the Landlord or the persons authorized by him have the right to enter the rental property even in the absence of the Tenant. If, in a case of imminent danger, the
rental property is unattended and the Tenant cannot be notified within the required period of time, public authorities (police, fire department) may be involved at the expense of the Tenant. The fire department or the fire
protection officer (the latter only in the presence of a fire warden who is an employee the Tenant, however) have the right to provide access using the general master key. 

  
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	3.	Upon notice of termination, dissolution or termination of the tenancy, the Tenant shall, within the notice period or the period to vacate the premises, in any case, however, within the last three months prior to
termination until the actual return of the rental property, allow prospective tenants to view the premises during normal business hours after arranging a time with the Tenant (at most, however, three time a week). 

XI. Purpose of Use / Subletting / 

Transferring the Rental Property to Third Parties 
  

	1.	The rental property may be used exclusively for commercial purposes in connection with the development of pharmaceuticals, preclinical and clinical research and biotechnology as well as relevant laboratory
activities (and connected or related activities). The Tenant shall comply with all legal and/or official regulations, orders and provisions applicable within the scope of his operation at his own expense and risk. The Tenant shall in
particular also ensure that all waste arising from his operation is treated and disposed of in compliance with the relevant legal and official specifications, orders and provisions; if possible via a direct contract between the Tenant and the
waste disposal company. 

 All official permits required for the business operation of the Tenant, including the
operational plant permit and supply and disposal contracts for public services, including the treatment and disposal of waste or substances and liquids/wastewater that require treatment, connection and supply of electrical power, media services
etc., shall be procured or concluded by the Tenant at his own expense and risk, and he shall bear all associated taxes, fees and charges. The Tenant shall fulfill all official requirements at his own expense and comply with all
relevant legal and official specifications, orders and provisions, and he shall also indemnify and hold the Landlord harmless in this respect. Should, however, due to the structural conditions of the rental property, it not be possible
to obtain an operational plant permit for operating a laboratory for biotechnology, the Tenant has the right to rescind the contract. 
  

	2.	The Tenant commits himself to take out business liability insurance with an appropriate scope of coverage and duly maintaining it for the duration of the term of the contract; evidence of the completion and the
effective existence of this business liability insurance shall promptly be provided to the Landlord upon request at any time. 

  
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	3.	Any change to the business purpose operated by the Tenant in the rental property or to the purpose of use of the rental property requires the prior express written approval of the Landlord.

  

	4.	After the end of a lease period of two years, but no later than 03/31/2021, the Tenant has the right to completely or partially sublet the rental property or completely or partially transfer it to third
parties of any kind whatsoever; in the event of such a subletting the rental property can, beyond the extent of Item XI.1, be used for office and/or laboratory purposes. 

 

	5.	If the Tenant has been granted further-reaching rights not limited in Item XI.5, the subletting or other transfer of the rental property to third parties is permitted only with prior express written
approval of the Landlord. For clarification it shall be noted that, even in the event of any subletting or other transfer of the rental property to third parties, the Tenant remains the sole contractual partner of the
Landlord. 

  

	6.	The use and/or subletting of the rental property to third parties for purposes other than those defined in the agreement is explicitly agreed upon as a reason for termination in the sense of § 30 Par. 2 Z 13
MRG; this does not affect the right of termination in accordance with other provisions. 

  

	7.	The Landlord declares that he will not under any circumstances derive legal consequences from the intended change of the Tenant’s ownership structure, if these changes take place within two years.

 XII. Notice of Termination / Premature Cancellation of the Contract 

 

	1.	Each contracting party has the right - without prejudice to the rendered waiver of termination in accordance with Item II.2 and/or II.3 - to terminate the tenancy effective to the last day of each calendar quarter,
subject to a notice period of six months, in writing; termination by the Landlord, however, is permissible only for one of the reasons for termination described in § 30 Par. 2 MRG or agreed upon in this contract, and only by means of
legal termination. 

  

	2.	The Landlord retains the right to premature cancellation of the lease agreement in accordance with § 1118 ABGB and for the reasons agreed upon in this Item XII.3, while the Tenant retains the right to
premature cancellation of the lease agreement in accordance with § 1117 ABGB. A premature cancellation of the lease agreement in accordance with § 1117 ABGB, however, insofar as not excluded by mandatory legal provisions, is permissible
only after setting a grace period of at least four weeks, if the Landlord does not place the rental property into a condition that makes it suitable for the stipulated use. 

  
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	3.	The Landlord has - aside from the reasons standardized in § 1118 ABGB - the right to cancel this lease agreement with immediate effect without observance of notice periods and/or termination dates, if the
Tenant does not meet his obligations and grossly or persistently violates the contract (despite written warning and written setting of a grace period). The Landlord in particular has the right to cancel the tenancy for the following reasons,
which are also explicitly agreed upon as material reasons for termination in the sense of § 30 Par. 2 line 13 MRG: 

  

	 	•	 	the Tenant does not make the contractually agreed upon payments despite written setting of a grace period of 14 days or does not extend or fill the bank guarantee (security deposit) in accordance with Item XV
within two months; 

  

	 	•	 	insolvency proceedings regarding the assets of the Tenant are opened and the company does not continue to operate or the opening of insolvency proceedings regarding the assets of the Tenant is rejected due
to the lack of assets to cover costs; 

  

	 	•	 	the contractually stipulated business purpose is changed without the Landlord’s approval; 

  

	 	•	 	the rental property is used for a purpose other than that stipulated by the contract; 

  

	 	•	 	the Tenant makes structural modifications that are subject to permission without the Landlord’s approval; 

  

	 	•	 	the Tenant does not fulfill or comply with legally binding official requirements or other legal provisions regarding the rental property or the operation conducted therein, insofar as in each case the
interests of the Landlord are jeopardized or impaired; 

  

	 	•	 	despite written warning and setting of a reasonable grace period, the Tenant behaves in an inconsiderate or otherwise grossly inappropriate manner toward the Landlord, other tenants or visitors and clients
of the building. 

 XIII. Offsetting 
  

	1.	The Tenant does not have the right to offset any counterclaims that he may raise against the Landlord under any title whatsoever extrajudicially and/or judicially against the rent, including all taxes,
fees, ancillary charges etc., unless they are legally binding or expressly acknowledged by the Landlord in writing. 

  
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 XIV. Return of
the Rental Property  
  

	1.	Upon termination of the tenancy, the Tenant is obligated to return the rental property to the Landlord broom-clean, clear of movables and, except for normal wear and tear, in the same condition as
on the day it was transferred to the Tenant. 

  

	2.	The Tenant shall remove any business signs and advertisements with the company logo at his own expense, properly remove all traces thereof and repair any resulting damage to the mounting location. In the event of
a violation of this provision, after setting a reasonable grace period, the Landlord has the right to arrange for the removal and disposal of the advertising material without further notice at the Tenant’s expense.

  

	3.	Movables left behind by the Tenant will become the property of the Landlord without entitlement to compensation; the Landlord reserves the right to have them disposed of without further action at
the expense and risk of the Tenant. 

  

	4.	All investments of the Tenant associated with the rental property that cannot be removed without damage to the substance, and/or without economic impairment, of the rental property, as well as
installations, additions and renovations performed by the Tenant, become the property of the Landlord without compensation upon termination of the tenancy. 

 

	5.	In the event of a termination of the contract for any reason whatsoever, the Tenant waives the assertion of compensation for any investments made. 

 

	6.	By mutual agreement it shall be noted that the rental property is transferred to the Tenant without any service, work or other employment relationship of any kind. Upon termination of the tenancy, the
Tenant shall ensure that no service, work or other employment relationships are transferred to the Landlord and entirely indemnify and hold the Landlord harmless in this respect with any and all expenditures of capital,
interest, damages and costs. 

 XV. Security Deposit 

 

	1.	 The Tenant commits himself, upon conclusion of this Lease Agreement, to transfer to the Landlord a
security deposit in the form of an abstract bank guarantee naming the Landlord as the beneficiary under the exclusion of avenues of recourse in the amount of three times the gross monthly rent at a first-class Austrian bank with at least an A
rating. The Tenant commits himself to increase this bank guarantee to six times the gross monthly rent upon transfer of the rental property. This bank guarantee liability serves to ensure that all his obligations arising from or in connection
with this Lease Agreement, including interest, 

  
 S01 - Lease Agreement Arsanis 101020

  -
 16
 - 
  

	 	damages and expenses, are respected. For the time being this bank guarantee shall be withdrawable for five years, but it shall, at least three months prior to expiration, continually be extended for at least another
five years in the amount of six times the then applicable gross monthly rent. In each case the bank guarantee shall include a provision that the right to use the bank guarantee and the right to withdraw the guarantee amount can, upon sale of the
rental property, be ceded to the respective legal successor of the Landlord. 

  

	2.	Instead of a bank guarantee, the Tenant also has the right to remit the deposit amount via a bank transfer or as a cash payment; otherwise § 16b MRG applies. 

 

	3.	In the event that the Tenant falls into arrears with a payment obligation arising from or in connection with this Lease Agreement, the Landlord, without prejudice to his right to proceed in accordance with
§ 1118 ABGB and § 30 Par. 2 line 1 MRG, has the right to withdraw the respective outstanding amount, in which case the Tenant is obligated to restore the security to the original amount within 14 days, whereby in the case of failure
to restore by bank guarantee, the restoration shall be made via a cash payment to the Landlord. 

  

	4.	If the Tenant violates his obligation regarding the contractual extension of the bank guarantee, the bank guarantee can be used with the full, respectively withdrawable guarantee amount; in the event of failure
to carry out the contractual extension of the bank guarantee the Tenant is nonetheless obligated to pay the deposit with a cash payment to the Landlord. Amounts not needed to cover existing claims shall be deposited into a bank
account, and serve to secure all obligations of the Tenant arising from or in connection with this Lease Agreement, including interest, damages and expenses. The accruing credit interest likewise serves as a security deposit; after
termination of the tenancy, however, it belongs to the Tenant. 

  

	5.	In the event that the Tenant then falls into arrears with a payment obligation arising from or in connection with this Lease Agreement, the Landlord, without prejudice to his right to proceed in accordance
with § 1118 ABGB and § 30 Par. 2 line 1 MRG, has the right to withdraw the respective outstanding amount from the bank account, in which case the Tenant is obligated to restore the security deposit to the original amount, plus the
credit interest that has accrued in the meantime, via a cash payment to the Landlord. 

 XVI. Fees and Charges

  

	1.	All taxes, fees and charges connected to this Lease Agreement, in particular the legal fees, are borne by the Tenant alone. In this respect as well, the Tenant indemnifies and holds the Landlord
entirely harmless. 

  
 S01 - Lease Agreement Arsanis 101020

  -
 17
 - 
  
  

	2.	For the purpose of fee assessment it shall be noted that the gross rent (base rent plus ancillary charges and value-added tax) for the rental property is €210,523.54 annually. 

 

	3.	The establishment of the Lease Agreement occurred solely on behalf of the Landlord. 

  

	4.	Each contracting party bears the costs of their own respective legal and tax counsel. 

XVII. Other Provisions 
  

	1.	In the event that the Landlord sells the property named in the preamble, this Lease Agreement with all the rights and obligations of the Landlord passes to the legal successor of the Landlord with
the ownership; the Landlord commits himself to transfer or impose all of the landlord’s rights and obligations arising from this Lease Agreement, including a waiver of termination as a result of sale (§ 1120 ABGB), to his legal
successor in the ownership; similarly, the Tenant declares that he will acknowledge the transfer of all rights and obligations of the Landlord to the legal successor of the Landlord in the ownership, and that he will waive termination
as a result of sale (§ 1120 ABGB). 

  

	2.	The contracting parties waive the rescission of the present contract on the grounds of error. 

  

	3.	Aside from this Lease Agreement there are no verbal side agreements. Changes and addenda to this Lease Agreement must be in writing to be valid. This also applies for a deviation from the written form requirement.

  

	4.	Any written or verbal agreements reached prior to conclusion of this Lease Agreement lose their validity upon conclusion of this contract. 

 

	5.	The nullity or inefficacy of individual provisions does not affect the validity of the other contract provisions. In the event of nullity or inefficacy of individual provisions of this Lease Agreement, the agreements
that are legally valid and come closest to the purpose of the null or ineffective provision are deemed to have been reached. The same applies in the event of a gap in the contract. 

 

	6.	This Lease Agreement is subject to Austrian law. For all disputes arising from or in connection with this Lease Agreement, the competence that is expressly agreed upon for the rental property is that of the court
that has jurisdiction with respect to the location, and for the dispute the court that has jurisdiction with respect to the subject-matter. 

  

	7.	This Lease Agreement is executed in two copies, of which each contracting party shall receive one. 

  
 S01 - Lease Agreement Arsanis 101020

  -
 18
 - 
  
  

	8.	All attachments constitute a component of the Lease Agreement. 

Attachments:       ./1     Notice of 02/18/2009, Number MA 37-BB/48393-1/2008 
 ./2     Site
plan 
 ./3     Contract plan 

./4     Building and interior description 

Vienna, on 11.26.2010 
  

			
	 /s/ Wolf-Dieter Jarisch

/s/ Reinhard Schertler

/s/ Manuela Moser-Ritzinger
	  	 /s/ Dr. Eszter Nagy

	Marxbox Bauprojekt GmbH & Co. OG	  	ARSANIS Biosciences GmbH

  
 S01 - Lease Agreement Arsanis 101020

			
	 Calculation of charges
 by Marxbox Bauprojekt
[Development] GmbH & Co. OG
 Percentage fee:
 Date of the
calculation:
  
 Vienna, on
                    
	  	 CALCULATION BILLING

Tax No.: 042 / 9505
 Serial
No.: 112         for OP/12
  

Charges: €5,300.38
  

Building Management Frieda Rustler

1150 Vienna, Mariahilfer Straße 196

	Marxbox Bauprojekt GmbH & Co. OG	  	

 ADDENDUM 

TO THE LEASE AGREEMENT OF 11/26/2010 

Entered into by 
 Marxbox Bauprojekt
GmbH & Co. OG 
 domiciled in Vienna 

(FN 346428 d) 
 1020 Vienna,
Messeplatz 1 
 referred to in the following as the Landlord, on the one hand, 

and 
 ARSANIS Biosciences GmbH 

domiciled in Vienna 
 (FN 354305
m) 
 1030 Vienna, Helmut Qualtinger Gasse 2 

referred to in the following as the Tenant, on the other hand, 

as follows: 
 Preamble 

 

	1.	On 11/26/2010 the contracting parties concluded a Lease Agreement for a part of the 3rd upper floor of the building 1030 Vienna, Helmut Qualtinger Gasse 2 constructed
on the property EZ 4359 Land Register 01006 Landstraße, District Court Inner City Vienna, with a dimension of ca. 698.10 m2, a storage bay on the 2nd basement level with a dimension of ca. 25 m2, and five garage parking spaces on the 1st
basement level allocated by the Landlord. 

  
 - 2 - 

	2.	The contracting parties have now agreed that, in addition to the above-named spaces, the Tenant will lease from the Landlord an additional space with an unconfirmed dimension of 458.98 m2 also on the 3rd upper floor of the building in question. The additional leased space—identified as “extension Arsanis”—is
shown in the contract plan (Attachment ./5) that is attached and constitutes an integral component of this Addendum to the Lease Agreement. 

  

	3.	Furthermore, upon completed transfer of the additional space leased with this addendum, the freely negotiated monthly base rent for all spaces on the 3rd upper floor
of €17.06 (excl. ancillary charges and VAT) per m2 of useable area (determined on the basis of the Consumer Price Index number for January 2012) will be increased by an amount of €2.65
(excl. ancillary charges and VAT) per m2 of useable area; the Consumer Price Index number for January 2012 is determinative for the further calculation of the indexation of both amounts. The
increase of €2.65 (excl. ancillary charges and VAT) per m2 of useable area as such does not represent an adjustment based on indexation. 

 

	4.	The Tenant will receive a non-refundable building cost subsidy in the amount of €100,000.00 (one hundred thousand Euros) from the Landlord that is due upon plan approval. This building cost subsidy is
earmarked specifically for the Tenant to commission S+B Plan & Bau GmbH (FN 129817 h of the Commercial Court Vienna), 1030 Vienna, Löwengasse 47, as the general contractor to increase the cooling capacity (installation of an
additional unit) in the rental property in accordance with the description in Attachment ./6; expenditures for measures that go beyond the description in Attachment ./6 shall be borne by the Tenant. 

 

	5.	This Addendum to the Lease Agreement thus supplements the agreement entered into by the parties on 11/26/2010, in particular with respect to the spaces on the 3rd
upper floor additionally leased by the Tenant and the building cost subsidy concerning the building described in more detail above and is an integral component of the Lease Agreement of 11/26/2010. Insofar as this Addendum to the Lease
Agreement of 11/26/2010 does not state an explicit modification, the (other) provisions of the Lease Agreement of 11/26/2010 remain in effect. The Lease Agreement of 11/26/2010 and this Addendum to the Lease Agreement are therefore one integrated
contract. 

  

	6.	This said, the parties agree to the following: 

  

	6.1	Item I.1 of the Lease Agreement is amended so that it now reads as follows: 

  

	 	“1.	 The Landlord leases to the Tenant and the latter leases from the
former the part of the 3rd upper floor that is marked in red in the contract plan (Attachment ./5), and labeled as “gross rented area”, of the building 1030 Vienna, Helmut

  
 - 3 - 

	 	Qualtinger Gasse 2, constructed on the property EZ 4359 Land Register 01006 Landstraße, District Court Inner City Vienna, with an overall dimension of ca. 1,157.08
m2, a storage bay on the 2nd basement level with a dimension of ca. 25 m2, and five garage parking spaces on the 1st basement level allocated
by the Landlord (referred to together in the following as rental property). The original contract plan Attachment ./3 is replaced by the contract plan Attachment ./5.” 

 

	6.2	Item I.3 and Item I.4 of the Lease Agreement are amended as follows: 

  

	 	“3.	The obligations of the Landlord concerning the construction of the rental property while taking into account the official regulations applicable at the time of the building
permit are finalized in the attached contract plans (Attachment ./5), which constitute an integral component of the Lease Agreement, or in the building and interior description (Attachment ./4), the description (Attachment ./6)
and the map presentation (Attachment ./7), whereby fitments and/or systems, equipment and devices possibly included in Attachment ./5—that are not also expressly named in the building and interior description (Attachment
../4)—have a purely illustrative character and do not create an obligation for the Landlord to provide the same. All changes or adaptations, systems, equipment and devices needed for the operation of the rental
property shall be performed or procured by the Tenant. The Landlord does, however, guarantee that the rental property is suitable from a structural perspective for obtaining an operational plant
permit for operating a biotechnology laboratory. 

  

	 	4.	The Landlord reserves the right to change or deviate from the aforementioned Attachments ./2, ./4, ./5, ./6 and ./7 if the change or deviation is minor, represents only a slight
disadvantage for the Tenant and is objectively justified, such as in particular 

  

	 	•	 	changes or deviations based on legal or official regulations, orders or requirements, 

  

	 	•	 	changes or deviations based on static or technical requirements or structural necessity, 

  

	 	•	 	changes or deviations based on the selection of equivalent or higher quality materials, equipment, devices and the like as a result of lack of availability, technical incompatibility and the like.”

  
 - 4 - 

	6.3	Item II.1 of the Lease Agreement is amended as follows: 

  

	 	“1.	The tenancy started with the transfer of the rental property (first part of ca. 698.10 m2) and was finalized for an indefinite period. The
extension by the second part [additional space] of ca. 458.98 m2 becomes effective upon transfer of the additional space.” 

 

	6.4	Item III.1 of the Lease Agreement is amended as follows: 

  

	 	“1.	The transfer and acceptance of the rental property take place as follows: for a first part of ca. 698.10 m2: with respect to the office spaces
within three months of the plan approval; with respect to the laboratory spaces within four months of the plan approval. For a second part [additional space] of ca. 458.98 m2: within four months
of the plan approval by the Tenant. The obligation of the Tenant to pay the agreed upon rent for the respective part of the rental property starts on the first of the month following the
respective transfer.” 

  

	a.	Item IV.2 of the Lease Agreement is amended as follows: 

  

	 	“2.	Base rent: 

 i.) Spaces on the
3rd upper floor 
 The freely negotiated monthly base rent for the first part
of the rental property is €17.00 (excl. VAT)—indexable in accordance with Item VI since transfer and thus, based on the Consumer Price Index number for January 2012, €17.06 - per m2 useable area. Upon transfer of the second part [additional space], the monthly rent for the entire rental property (first and second part) increases by €2.65 (exc. VAT) per
m2 useable area; it shall be noted that these spaces (first and second part) have a total useable area of ca. 1,157.08 m2. 

ii.) Garage parking spaces 

The freely negotiated monthly base rent is €98.50 (excl. VAT) per parking space. 

  
 - 5 - 

 iii.) Storage bay in the basement 

The freely negotiated monthly base rent is €6.50 (excl. VAT) per m2 useable area;
it shall be noted that storage bay has a useable area of ca. 25 m2.” 
  

	b.	Item VI.1 of the Lease Agreement is amended so that it now reads as follows: 

  

	 	“1.	The agreed upon base rent is adjusted by linking to the Consumer Price Index 2005 announced by Statistik Austria [Austrian Statistical Office] or the successor index replacing it. In the event that no successor index
is announced, the adjustment shall be calculated in such a way that it corresponds to the decrease/increase of the general purchasing power. The starting point for the adjustment is generally the index number announced for the month of the
acceptance of the first part of the rental property, for the increase referred to in Item IV.2. i) (namely for both the first and the second part of the rental property), however, the index number for
January 2012 applies.” 

  

	c.	The Lease Agreement is supplemented by the paragraph below, which reads as follows: 

 VI.a
Building Cost Subsidy 
 The Tenant will receive a non-refundable building cost subsidy in the amount of
€100,000.00 (one hundred thousand Euros) from the Landlord. The building cost subsidy is due upon plan approval. This building cost subsidy is earmarked specifically for the Tenant to commission S+B
Plan & Bau GmbH (FN 129817 h of the Commercial Court Vienna), 1030 Vienna, Löwengasse 47, as the general contractor to increase the cooling capacity (installation of an additional unit) in the rental property in
accordance with the description in Attachment ./6; expenditures for measures that go beyond the description in Attachment ./6 shall be borne by the Tenant. 

 

	4.	Fees incurred in connection with the finalization of this Addendum shall be borne by the Tenant, who in this respect indemnifies and holds the Landlord harmless. 

 

	5.	All attachments constitute a component of the Lease Agreement. 

 Attachments:   ./5
    Contract plan 

	 	./6	Description additional services with respect to BAB request Arsanis 

	 	./7	Set-up map presentation to define the technical building services equipment 

 HKLS 

  
 - 6 - 

 Vienna, on 08.31.2012 
  

			
	 /s/ Wolf-Dieter Jarisch

/s/ Reinhard Schertler

/s/ Manuela Moser-Ritzinger
	  	 /s/ Dr. Eszter Nagy

	Marxbox Bauprojekt GmbH & Co. OG	  	ARSANIS Biosciences GmbH

			
	 Self-calculation of fees
 by the Marxbox
Bauprojekt GmbH & Co. OG
 Percentage fee: €
 Date of
self-calculation:
 Vienna,
dated                    
 Marxbox Bauprojekt
GmbH & Co. OG
	  	 Self-calculation of fees
 Tax ID:
042 / 9505
 Cont. no.: 104 for: [hw:] 10/12
 Fee amount:
€ 117.72
 Building administration Frieda Rustler

1150 Vienna, Mariahilfer Str. 196

 SECOND AMENDMENT 

OF THE LEASE AGREEMENT DATED 11/26/2010 

AND THE FIRST AMENDMENT DATED 08/31/2012 

entered into by 
 Marxbox Bauprojekt
GmbH & Co. OG 
 with headquarters in Vienna 

(FN 346428 d) 
 1020 Vienna,
Messeplatz 1 
 hereinafter called lessor for short, on the one side, 

and 
 ARSANIS Biosciences GmbH 

with headquarters in Vienna 
 (FN
354305 m) 
 1030 Vienna, Helmut-Qualtinger-Gasse 2 

hereinafter called tenant for short, on the other side, 

as follows: 
 Preamble 

Contract: Lease agreement dated 11/26/2010 (Attachment ./1): 3rd upper floor (698.10 m2), storage unit 2nd lower level (25 m2), 5 parking spaces in the garage. 

Amendment of the lease agreement (Attachment ./2): additional area 3rd upper floor (expansion to a total
of 1,157.08 m2). 

  

 2 
  

Term: unlimited term, the tenant waives the right to cancel until 04/30/2021; unless a regular cancellation occurs by 04/30/2021 the waiver of
cancellation will be automatically extended by another year. 
 Rent: primary monthly rent: 3rd
upper floor originally € 17.00 (incl. VAT) per m2, with additional area 3rd upper floor € 19.71 (excl. VAT) per m2, 2nd lower level € 6.50 (excl. VAT) per m2, parking spaces in the garage € 98.50
(excl. VAT) per parking space. 
 The contractual parties have now agreed that the tenant rents two parking spaces in addition to the previously
rented five parking spaces. This said, the contractual parties agree to the following: 
 Second amendment of the lease agreement dated
11/26/2010 
 Topic 1.1 of the lease agreement is hereby amended such that now it is worded as follows: 

 

	“1.	The lessor rents to the tenant and said tenant rents from the lessor the portion of the 3rd upper
floor (OG), marked as “gross lease area” and framed in red in the contractual plan (Attachment ./5), of the building 1030 Vienna, Helmut-Qualtinger-Gasse 2, erected on the real property EZ 4359, land registry 01006 Landstraße,
District Court Inner City of Vienna, showing a total size of approx. 1,157.08 m2, a storage unit in the 2nd lower level showing a size of
approx. 25.00 m2, and five parking spaces, allocated by the lessor in the garage in the 1st lower level, as of 09/17/2012
seven of them, (hereinafter called jointly lease object). The original contractual plan Attachment ./3 is replaced by the contractual plan Attachment ./5” 

Topic IV.2.ii.) of the lease agreement is hereby amended such that now it is worded as follows: 

“ii.) Parking spaces in the garage 

The freely agreed monthly primary rent amounts to € 98.50 (excl. VAT) per parking space in the garage. For the parking spaces rented as
of 09/17/2012 the freely agreed monthly primary rent amounts to € 100,00 (excl. VAT) per parking space in the garage.” 
 The second amendment
in question refers to the agreement entered into by the contractual parties and becomes an integral component of the lease agreement dated 11/26/2010, amended by the first amendment dated 08/31/2012. Unless in this second amendment no explicit
changes are listed, the stipulations of the lease agreement dated 11/26/2010, amended by the first amendment dated 08/31/2012, remain effective. 

  
  

 3 
  

Therefore, the lease agreement dated 11/26/2010, with the first amendment dated 08/31/2012 and the present second amendment, represents a contractual unit.

 Any and all fees arising in the context with this second amendment being entered into shall be payable by the tenant, who releases the
lessor from any and all damages and legal disputes to this regard. 
 This amendment shall be prepared in two copies, with each contractual party
being provided with one of them. 
  

					
	Attachments:	  	./1	  	Lease agreement dated 11/26/2010
		  	./2	  	Amendment dated 08/31/2012

 Vienna, dated 09/17/2012 
  

			
	  
	  	 /s/ Dr. Eszter Nagy

	Marxbox Bauprojekt GmbH & Co. OG	  	ARSANIS Biosciences GmbH

 Represented by: 
  

					
		  	Wüstenrot	  	
		  	Versicherungs-AG	  	
		  	 /s/ V Dir. Franz
Meingast            /s/ Pro K. Brigette Hafner
	  	
	09 Oct. 2012	  	WV Immobilien GmbH	  	

  
  

 EXISTING TENANCY AGREEMENT 

 

					
	PROPERTY:	  	Helmut Qualtinger Gasse 2, 1030 Vienna	  	
		  		  	
		  		  	Oct. 29, 2014
		
	LANDLORD:	  	Wüstenrot Marxbox GmbH & Co. OG
		
	TENANT:	  	ARSANIS Biosciences GmbH
		
	LEASE AGREEMENT:	  	11/26/2010
		
	Space:	  	3rd upper floor: 698.10 m2 office and laboratory; 2nd
basement level: 25 m2 storage bay
		
	Parking spaces:	  	5 (on the 1st basement level)
		
	Term:	  	indefinite period, Tenant’s waiver of the right to terminate prior to 04/30/2021; if Tenant does not terminate with statutory notice prior to 04/30/2021, extension of the waiver of the right to terminate to
04/30/2022
		
	Rent:	  	Office and Laboratory: €17.00/m2 (excl. VAT) per month, storage bay: €6.50/m2 (excl. VAT) per month,
parking spaces: €98.50 (excl. VAT) per parking space per month; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	1st ADDENDUM:	  	08/31/2012
		
	Space:	  	3rd upper floor: 458.98 m2 additional
		
	Term:	  	as before
		
	Rent:	  	€19.71/m2 (excl. VAT) per month as of transfer of the additional space for the entire area on the 3rd upper
floor
		
	Furthermore:	  	building cost subsidy for the Tenant of €100,000.00
		
	2nd ADDENDUM:	  	10/09/2012
		
	Parking spaces:	  	2 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€100.00 (excl. VAT) per parking space per month for the additional parking spaces
		
	3rd ADDENDUM:	  	
		
	Space:	  	2 bicycle parking spaces (0.80 m2) in the bicycle room (ground floor)
		
	Term:	  	as before
		
	Rent:	  	€10.00 (excl. VAT) per parking space per month; payment of ancillary charges: €2.50/m2 (excl. VAT) per month

  
 - 2 - 

 

			
	 Calculation of charges
 by Wüstenrot
Marxbox GmbH & Co. OG
 Percentage fee: €9.50
 Date of
the calculation:
  
 Vienna,
on                              
	  	 CALCULATION BILLING

Tax No.: 042 / 9505
  

Serial No.: 126 for 10/14
  

Charges: €9.50
  

Building Management Frieda Rustler

1150 Vienna, Mariahilfer Straße 196

		
	Wüstenrot Marxbox GmbH & Co. OG	  	

 3rd ADDENDUM 

TO THE LEASE AGREEMENT OF 11/26/2010 

entered into by 
 Wüstenrot Marxbox
GmbH & Co. OG 
 domiciled in Vienna 

(FN 346428d Regional Court Salzburg) 

5033 Salzburg, Alpenstraße 61 
 referred
to in the following as the Landlord, on the one hand, and 
 ARSANIS Biosciences GmbH 

domiciled in Vienna 
 (FN
354305m Commercial Court Vienna) 
 1030 Vienna, Helmut Qualtinger Gasse 2 

referred to in the following as the Tenant, on the other hand, as follows: 
  

	1.	The contracting parties entered into a Lease Agreement (Attachment ./1) on 11/26/2010 as well as a 1st Addendum (Attachment ./2) on 08/31/2012 and a 2nd Addendum to the Lease Agreement (Attachment ./3) on 10/09/2012, which constitute integral components of this 3rd Addendum, for rented
areas in the building at 1030 Vienna, Helmut Qualtinger Gasse 2. 

  

	2.	The contracting parties have now agreed that the Tenant will additionally lease from the Landlord two bicycle parking spaces with a useable area per parking space of ca. 0.40 m2 in the bicycle room on the ground floor of the aforementioned building for keeping two bicycles. 

  

	3.	In this context it shall explicitly be noted that this 3rd Addendum to the Lease Agreement does not grant the Tenant the right to use specific bicycle parking
spaces. The Tenant is entitled to parking spaces without a definition of specific assigned spaces; he can choose from among the currently free spaces in the bicycle room. 

  
 - 3 - 

 

	4.	This 3rd Addendum to the Lease Agreement supplements the understanding entered into by the parties with the Lease Agreement of 11/26/2010, as well as with the 1st Addendum of 08/31/2012 and the 2nd Addendum of 10/09/2012 to the Lease Agreement. The rented areas identified in the Lease Agreement of
11/26/2010, in the 1st Addendum of 08/31/2012 and in the 2nd Addendum of 10/09/2012 to the Lease Agreement and the bicycle parking spaces
identified under Item 2 in this 3rd Addendum to the Lease Agreement together constitute the rental property. 

 

	5.	The tenancy for the bicycle parking spaces begins with the transfer and acceptance of the keys to the bicycle room. The transfer and acceptance of the keys to the bicycle room will occur upon signing of this 3rd Addendum to the Lease Agreement. 

  

	6.	The monthly rent for the bicycle parking spaces in accordance with Item 2 of this 3rd Addendum to the Lease Agreement is €10.00 (excl. VAT) per parking
space. Pending further assessment by the Landlord, the monthly payment of ancillary charges for the parking spaces is €2.50 per m2 useable area. 

 

	7.	Insofar as this 3rd Addendum to the Lease Agreement does not state explicit modifications, the other provisions of the Lease Agreement of 11/26/2010, the 1st Addendum of 08/31/2012 and the 2nd Addendum of 10/09/2012 to the Lease Agreement remain in effect. The Lease Agreement of 11/26/2010, the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012 and this 3rd Addendum to the Lease
Agreement are therefore one integrated contract. 

  

	8.	Any fees incurred in connection with the finalization of this Addendum shall be borne by the Tenant, who in this respect indemnifies and holds the Landlord harmless. 

 

	9.	This Addendum is executed in two copies, of which each contracting party shall receive one. 

  

					
	Attachments:	  	./1	  	Lease Agreement of 11/26/2010
		  	./2	  	1st Addendum to the Lease Agreement of 08/31/2012
		  	./3	  	2nd Addendum to the Lease Agreement of 10/09/2012

 Vienna, on June 04, 2014 
  

			
	 Wüstenrot Marxbox GmbH & Co. OG

WV Immobilien GmbH
	  	
		
	 /s/ Josef Millonigg    /s/ GF Mag. Wolfgang Schantl
	  	 /s/ Eszter Nagy

	Wüstenrot Marxbox GmbH & Co. OG	  	ARSANIS Biosciences GmbH

 EXISTING TENANCY AGREEMENT 

 

			
	PROPERTY:	  	Helmut Qualtinger Gasse 2, 1030 Vienna
		
	LANDLORD:	  	Wüstenrot Marxbox GmbH & Co. OG
		
	TENANT:	  	ARSANIS Biosciences GmbH
		
	LEASE AGREEMENT:    	  	11/26/2010
		
	Space:	  	3rd upper floor: 698.10 m2 office and laboratory; 2nd basement level: 25
m2 storage bay
		
	Parking spaces:	  	5 (on the 1st basement level)
		
	Term:	  	indefinite period, Tenant’s waiver of the right to terminate prior to 04/30/2021; if Tenant does not terminate with statutory notice prior to 04/30/2021, extension of the waiver of the right to terminate to 04/30/2022
		
	Rent:	  	Office and Laboratory: €17.00/m2 (excl. VAT) per month, storage bay: €6.50/m2 (excl. VAT) per month, parking spaces:
€98.50 (excl. VAT) per parking space per month; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	1st ADDENDUM:	  	08/31/2012
		
	Space:	  	3rd upper floor: 458.98 m2 additional
		
	Term:	  	as before
		
	Rent:	  	€19.71/m2 (excl. VAT) per month as of transfer of the additional space for the entire area on the 3rd upper
floor
		
	Furthermore:	  	building cost subsidy for the Tenant of €100,000.00
		
	2nd ADDENDUM:	  	10/09/2012
		
	Parking spaces:	  	2 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€100.00 (excl. VAT) per parking space per month for the additional parking spaces
		
	3rd ADDENDUM:	  	
		
	Space:	  	2 bicycle parking spaces (0.80 m2) in the bicycle room (ground floor)
		
	Term:	  	as before
		
	Rent:	  	€10.00 (excl. VAT) per parking space per month; payment of ancillary charges: €2.50/m2 (excl. VAT) per month

  
  

  -
 32
 - 
  
  

			
	 Calculation of charges
 by Wüstenrot
Marxbox GmbH & Co. OG
 Percentage fee: €2,475.79
 Date
of the calculation:
  
 Vienna, on _______________

 
 Wüstenrot Marxbox GmbH & Co. OG
	  	 CALCULATION BILLING

Tax No.: 042 / 9505
  

Serial No.: 127 for 10/14
  

Charges: €2,475.79
  

Building Management Frieda Rustler

1150 Vienna, Mariahilfer Straße 196

		
		  	

 4th ADDENDUM 

TO THE LEASE AGREEMENT OF 11/26/2010 

entered into by 
 Wüstenrot Marxbox
GmbH & Co. OG 
 domiciled in Vienna 

(FN 346428d Regional Court Salzburg) 

5033 Salzburg, Alpenstraße 61 
 referred
to in the following as the Landlord, on the one hand, and 
 ARSANIS Biosciences GmbH 

domiciled in Vienna 
 (FN
354305m Commercial Court Vienna) 
 1030 Vienna, Helmut Qualtinger Gasse 2 

referred to in the following as the Tenant, on the other hand, as follows: 
  

	1.	The contracting parties entered into a Lease Agreement (Attachment ./1) on 11/26/2010, a 1st Addendum (Attachment ./2) on 08/31/2012, a 2nd Addendum (Attachment ./3) on 10/09/2012, and a 3rd Addendum to the Lease Agreement (Attachment ./4) on 03/31/2014, which constitute
integral components of this 4th Addendum, for rented areas in the building on the property EZ 4359 Land Register 01006 Landstraße, District Court Inner City Vienna, consisting of Lot
No. 1449/3, with the address 1030 Vienna, Helmut Qualtinger Gasse 2. 

  

	2.	The contracting parties have now agreed that, in addition to the premises already included in accordance with Attachments ./1 to ./4, the Tenant will lease from the Landlord additional premises with
an unconfirmed dimension of 277.53 m2 on the 2nd upper floor of the building identified in Item 1. The additionally leased premises are
marked in red in the attached contract plan (Attachment ./5), which constitutes an integral component this 4th Addendum to the Lease Agreement. 

  -
 33
 - 
  
  

					
	Attachments:	  	./1	  	Lease Agreement of 11/26/2010
		  	./2	  	1st Addendum to the Lease Agreement of 08/31/2012
		  	./3	  	2nd Addendum to the Lease Agreement of 10/09/2012
		  	./4	  	3rd Addendum to the Lease Agreement of 03/31/2014
		  	./5	  	Contract plan
		  	./6	  	List of equipment

 Vienna, on June 04, 2014 
  

			
	 Wüstenrot Marxbox GmbH & Co. OG

WV Immobilien GmbH
	  	
		
	 /s/ GF Mag. Wolfgang Schantl    /s/ Josef Millonigg
	  	 /s/ Dr. Eszter Nagy

	Wüstenrot Marxbox GmbH & Co. OG	  	ARSANIS Biosciences GmbH

 EXISTING TENANCY AGREEMENT 

 

			
	PROPERTY:	  	Helmut Qualtinger Gasse 2, 1030 Vienna
		
	LANDLORD:	  	Wüstenrot Marxbox GmbH & Co. OG
		
	TENANT:	  	ARSANIS Biosciences GmbH
		
	LEASE AGREEMENT:    	  	11/26/2010
		
	Space:	  	3rd upper floor: 698.10 m2 office and laboratory; 2nd basement level: 25 m2
storage bay
		
	Parking spaces:	  	5 (on the 1st basement level)
		
	Term:	  	indefinite period, Tenant’s waiver of the right to terminate prior to 04/30/2021; if Tenant does not terminate with statutory notice prior to 04/30/2021, extension of the waiver of the right to terminate to 04/30/2022
		
	Rent:	  	Office and Laboratory: €17.00/m2 (excl. VAT) per month, storage bay: €6.50/m2 (excl. VAT) per month, parking spaces:
€98.50 (excl. VAT) per parking space per month; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	1st ADDENDUM:	  	08/31/2012
		
	Space:	  	3rd upper floor: 458.98 m2 additional
		
	Term:	  	as before
		
	Rent:	  	€19.71/m2 (excl. VAT) per month as of transfer of the additional space for the entire area on the 3rd upper floor
		
	Furthermore:	  	building cost subsidy for the Tenant of €100,000.00
		
	2nd ADDENDUM:	  	10/09/2012
		
	Parking spaces:	  	2 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€100.00 (excl. VAT) per parking space per month for the additional parking spaces; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	3rd ADDENDUM:	  	06/04/2014
		
	Space:	  	2 bicycle parking spaces (0.80 m2) in the bicycle room (ground floor)
		
	Term:	  	as before
		
	Rent:	  	€10.00 (excl. VAT) per parking space per month; payment of ancillary charges: €2.50/m2 (excl. VAT) per month

  
 - 2 - 

 

			
	4th ADDENDUM:	  	06/04/2014
		
	Space:	  	2nd upper floor: 277.53 m2 additional
		
	Term:	  	as before
		
	Rent:	  	 €17.75/m2 (excl. VAT) per month; payment of ancillary charges:

€2.90/m2 (excl. VAT) per month

		
	5th ADDENDUM:	  	
		
	Parking spaces:	  	1 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€104.31 (excl. VAT) per parking space per month for the additional parking space; payment of ancillary charges: €2.90/m2 (excl. VAT) per month

  
 - 3 - 

 

 Calculation of charges 

by Wüstenrot Marxbox GmbH & Co. OG 
 Percentage fee:
€58.84 
 Date of the calculation: 
 Vienna, on
                         

Wüstenrot Marxbox GmbH & Co. OG 

5th ADDENDUM 

TO THE LEASE AGREEMENT OF 11/26/2010 

entered into by 
 Wüstenrot Marxbox
GmbH & Co. OG 
 domiciled in Vienna 

(FN 346428d Regional Court Salzburg) 

5033 Salzburg, Alpenstraße 61 
 referred
to in the following as the Landlord, on the one hand, and 
 ARSANIS Biosciences GmbH 

domiciled in Vienna 
 (FN
354305m Commercial Court Vienna) 
 1030 Vienna, Helmut Qualtinger Gasse 2 

referred to in the following as the Tenant, on the other hand, as follows: 
  

	1.	The contracting parties entered into a Lease Agreement (Attachment ./1) on 11/26/2010, a 1st Addendum (Attachment ./2) on 08/31/2012, a 2nd Addendum (Attachment ./3) on 10/09/2012, a 3rd Addendum (Attachment ./4) on 06/04/2014 and, likewise on 06/04/2014, a 4th Addendum to the Lease Agreement (Attachment ./5), which constitute integral components of this 5th Addendum, for rented areas or parking
spaces in the building on the property EZ 4359 Land Register 01006 Landstraße, District Court Inner City Vienna, consisting of Lot No. 1449/3, with the address 1030 Vienna, Helmut Qualtinger Gasse 2. 

 

	2.	The contracting parties have now agreed that, in addition to the premises and parking spaces already included in accordance with Attachments ./1 to ./5, the Tenant will lease from the Landlord an
additional parking space on the 1st basement level of the building identified in Item 1. 

  
 - 4 - 

 

	3.	The tenancy for the additional parking space begins with the transfer and acceptance of the rental property in accordance with Item 2 of this 5th Addendum to the
Lease Agreement. 

  

	4.	The monthly rent for the additional parking space in accordance with Item 2 of this 5th Addendum to the Lease Agreement is €104.31 (excl. VAT) per parking
space. Pending further assessment by the Landlord, the monthly payment of ancillary charges for the parking spaces is €2.90 (excl. VAT) per m2 useable area. 

 

	5.	This 5th Addendum to the Lease Agreement supplements the understanding entered into by the parties with the Lease Agreement of 11/26/2010, as well as with the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum of 06/04/2014 and
the 4th Addendum to the Lease Agreement, likewise of 06/04/2014. The rented areas identified in the Lease Agreement of 11/26/2010, in the 1st
Addendum of 08/31/2012, in the 2nd Addendum of 10/09/2012, in the 3rd Addendum of 06/04/2014 and in the 4th Addendum to the Lease Agreement, likewise of 06/04/2014 and the additional parking space identified under Item 2 in this 5th Addendum to the
Lease Agreement together constitute the rental property. 

  

	6.	Insofar as this 5th Addendum to the Lease Agreement does not state explicit modifications, the other provisions of the Lease Agreement of 11/26/2010, the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum of 06/04/2014 and
the 4th Addendum, likewise of 06/04/2014, remain in effect. The Lease Agreement of 11/26/2010, the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum of 06/04/2014, the 4th Addendum, likewise of
06/04/2014, and this 5th Addendum to the Lease Agreement are therefore one integrated contract. 

  

	7.	Any fees incurred in connection with the finalization of this 5th Addendum to the Lease Agreement shall be borne by the Tenant, who in this respect indemnifies
and holds the Landlord completely harmless. 

  

	8.	This 5th Addendum to the Lease Agreement is executed in two copies, of which each contracting party shall receive one. 

  
 - 5 - 

 

					
	Attachments:	  	./1	  	Lease Agreement of 11/26/2010
		  	./2	  	1st Addendum to the Lease Agreement of 08/31/2012
		  	./3	  	2nd Addendum to the Lease Agreement of 10/09/2012
		  	./4	  	3rd Addendum to the Lease Agreement of 06/04/2014
		  	./5	  	4th Addendum to the Lease Agreement of 06/04/2014

 Vienna, on June 30, 2014 
  

			
	 Wüstenrot Marxbox GmbH & Co. OG

WV Immobilien GmbH
	  	
		
	 /s/ GF Mag. Wolfgang Schantl    /s/ Josef Millonigg
	  	 /s/ Eszter Nagy

	Wüstenrot Marxbox GmbH & Co. OG	  	ARSANIS Biosciences GmbH

 EXISTING TENANCY AGREEMENT 

 

			
	PROPERTY:	  	Helmut Qualtinger Gasse 2, 1030 Vienna
		
	LANDLORD:	  	Wüstenrot Marxbox GmbH & Co. OG
		
	TENANT:	  	ARSANIS Biosciences GmbH
		
	LEASE AGREEMENT:	  	11/26/2010
		
	Space:	  	3rd upper floor: 698.10 m2 office and laboratory; 2nd basement level: 25 m2
storage bay
		
	Parking spaces:	  	5 (on the 1st basement level)
		
	Term:	  	indefinite period, Tenant’s waiver of the right to terminate prior to 04/30/2021; if Tenant does not terminate with statutory notice prior to 04/30/2021, extension of the waiver of the right to terminate to 04/30/2022
		
	Rent:	  	Office and Laboratory: €17.00/m2 (excl. VAT) per month, storage bay: €6.50/m2 (excl. VAT) per month, parking spaces:
€98.50 (excl. VAT) per parking space per month; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	1st ADDENDUM:	  	08/31/2012
		
	Space:	  	3rd upper floor: 458.98 m2 additional
		
	Term:	  	as before
		
	Rent:	  	€19.71/m2 (excl. VAT) per month as of transfer of the additional space for the entire area on the 3rd upper floor
		
	Furthermore:	  	building cost subsidy for the Tenant of €100,000.00
		
	2nd ADDENDUM:	  	10/09/2012
		
	Parking spaces:	  	2 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€100.00 (excl. VAT) per parking space per month for the additional parking spaces; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	3rd ADDENDUM:	  	06/04/2014
		
	Space:	  	2 bicycle parking spaces (0.80 m2) in the bicycle room (ground floor)
		
	Term:	  	as before
		
	Rent:	  	€10.00 (excl. VAT) per parking space per month; payment of ancillary charges: €2.50/m2 (excl. VAT) per month

  
 2 

 

			
	4th ADDENDUM:	  	06/04/2014
		
	Space:	  	2nd upper floor: 277.53 m2 additional
		
	Term:	  	as before
		
	Rent:	  	€17.75/m2 (excl. VAT) per month; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	5th ADDENDUM:	  	
		
	Parking spaces:	  	1 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€104.31 (excl. VAT) per parking space per month for the additional parking space; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	6th ADDENDUM:	  	
		
	Parking spaces:	  	1 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€104.31 (excl. VAT) per parking space per month for the additional parking space; payment of ancillary charges: €2.90/m2 (excl. VAT) per month

  
 3 

 

			
	 Calculation of charges
 by Wüstenrot
Marxbox GmbH & Co. OG
 Percentage fee: €58.84
 Date of
the calculation: 08/22/2014
  
 Vienna, on 08/22/2014

 
 Wüstenrot Marxbox GmbH & Co. OG
	  	 CALCULATION BILLING

Tax No.: 042 / 9505
  

Serial No.: 91 for 08/14
  

Charges: €58.84
  

Building Management Frieda Rustler

1150 Vienna, Mariahilfer Straße 196

 6th ADDENDUM 

TO THE LEASE AGREEMENT OF 11/26/2010 

entered into by 
 Wüstenrot Marxbox
GmbH & Co. OG 
 domiciled in Vienna 

(FN 346428d Regional Court Salzburg) 

5033 Salzburg, Alpenstraße 61 
 referred
to in the following as the Landlord, on the one hand, and 
 ARSANIS Biosciences GmbH 

domiciled in Vienna 
 (FN
354305m Commercial Court Vienna) 
 1030 Vienna, Helmut Qualtinger Gasse 2 

referred to in the following as the Tenant, on the other hand, as follows: 
  

	1.	The contracting parties entered into a Lease Agreement (Attachment ./1) on 11/26/2010, a 1st Addendum (Attachment ./2) on 08/31/2012, a 2nd Addendum (Attachment ./3) on 10/09/2012, a 3rd Addendum (Attachment ./4) on 06/04/2014 and, likewise on 06/04/2014, a 4th Addendum (Attachment ./5), as well as a 5th Addendum to the Lease Agreement (Attachment ./6) on 06/30/2014, which constitute
integral components of this 6th Addendum, for rented areas or parking spaces in the building on the property EZ 4359, Land Register 01006 Landstraße, District Court Inner City Vienna,
consisting of Lot No. 1449/3, with the address 1030 Vienna, Helmut Qualtinger Gasse 2. 

  

	2.	The contracting parties have now agreed that, in addition to the premises and parking spaces already included in accordance with Attachments ./1 to ./6, the Tenant will lease from the Landlord an
additional parking space on the 1st basement level of the building identified in Item 1. 

  
 4 

 

	3.	The tenancy for the additional parking space begins with the transfer and acceptance of the rental property in accordance with Item 2 of this 6th Addendum to the
Lease Agreement. 

  

	4.	The monthly rent for the additional parking space in accordance with Item 2 of this 6th Addendum to the Lease Agreement is €104.31 (excl. VAT) per parking
space. Pending further assessment by the Landlord, the monthly payment of ancillary charges for the parking spaces is €2.90 (excl. VAT) per m2 useable area. 

 

	5.	This 6th Addendum to the Lease Agreement supplements the understanding entered into by the parties with the Lease Agreement of 11/26/2010, as well as with the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum of 06/04/2014, the
4th Addendum, likewise of 06/04/2014, and the 5th Addendum to the Lease Agreement of 06/30/2014. The rented areas identified in the Lease
Agreement of 11/26/2010, in the 1st Addendum of 08/31/2012, in the 2nd Addendum of 10/09/2012, in the 3rd Addendum of 06/04/2014, in the 4th Addendum, likewise of 06/04/2014, and in the 5th Addendum
to the Lease Agreement of 06/30/2014 and the additional parking space identified under Item 2 in this 6th Addendum to the Lease Agreement together constitute the rental property.

  

	6.	Insofar as this 6th Addendum to the Lease Agreement does not state explicit modifications, the other provisions of the Lease Agreement of 11/26/2010, the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum of 06/04/2014, the
4th Addendum, likewise of 06/04/2014, and the 5th Addendum of 06/30/2014 remain in effect. The Lease Agreement of 11/26/2010, the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum of 06/04/2014, the
4th Addendum, likewise of 06/04/2014, the 5th Addendum of 06/30/2014 and this 6th Addendum
to the Lease Agreement are therefore one integrated contract. 

  

	7.	Any fees incurred in connection with the finalization of this 6th Addendum to the Lease Agreement shall be borne by the Tenant, who in this respect indemnifies
and holds the Landlord completely harmless. 

  

	8.	This 6th Addendum to the Lease Agreement is executed in two copies, of which each contracting party shall receive one. 

  
 5 

 

					
	Attachments:	  	./1	  	Lease Agreement of 11/26/2010
		  	./2	  	1st Addendum to the Lease Agreement of 08/31/2012
		  	./3	  	2nd Addendum to the Lease Agreement of 10/09/2012
		  	./4	  	3rd Addendum to the Lease Agreement of 06/04/2014
		  	./5	  	4th Addendum to the Lease Agreement of 06/04/2014
		  	./6	  	5th Addendum to the Lease Agreement of 06/30/2014

 Vienna, on Aug. 13, 2014 
  

			
	 Wüstenrot Marxbox GmbH & Co. OG

WV Immobilien GmbH
	  	
		
	 /s/ GF Mag. Wolfgang Schantl    /s/ Josef Millonigg
	  	 /s/ Dr. Eszter Nagy

	Wüstenrot Marxbox GmbH & Co. OG	  	ARSANIS Biosciences GmbH

 EXISTING TENANCY AGREEMENT 

 

			
	PROPERTY:	  	Helmut Qualtinger Gasse 2, 1030 Vienna
		
	LANDLORD:	  	Wüstenrot Marxbox GmbH & Co. OG
		
	TENANT:	  	ARSANIS Biosciences GmbH
		
	LEASE AGREEMENT:	  	11/26/2010
		
	Space:	  	3rd upper floor: 698.10 m2 office and laboratory; 2nd basement level: 25 m2
storage bay
		
	Parking spaces:	  	5 (on the 1st basement level)
		
	Term:	  	indefinite period, Tenant’s waiver of the right to terminate prior to 04/30/2021; if Tenant does not terminate with statutory notice prior to 04/30/2021, extension of the waiver of the right to terminate to 04/30/2022
		
	Rent:	  	Office and Laboratory: €17.00/m2 (excl. VAT) per month, storage bay: €6.50/m2 (excl. VAT) per month, parking spaces:
€98.50 (excl. VAT) per parking space per month; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	1st ADDENDUM:	  	08/31/2012
		
	Space:	  	3rd upper floor: 458.98 m2 additional
		
	Term:	  	as before
		
	Rent:	  	€19.71/m2 (excl. VAT) per month as of transfer of the additional space for the entire area on the 3rd upper floor
		
	Furthermore:	  	building cost subsidy for the Tenant of €100,000.00
		
	2nd ADDENDUM:	  	10/09/2012
		
	Parking spaces:	  	2 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€100.00 (excl. VAT) per parking space per month for the additional parking spaces; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	3rd ADDENDUM:	  	06/04/2014
		
	Space:	  	2 bicycle parking spaces (0.80 m2) in the bicycle room (ground floor)
		
	Term:	  	as before
		
	Rent:	  	€10.00 (excl. VAT) per parking space per month; payment of ancillary charges: €2.50/m2 (excl. VAT) per month

 2 
  

 

			
	4th ADDENDUM:	  	06/04/2014
		
	Space:	  	2nd upper floor: 277.53 m2 additional
		
	Term:	  	as before
		
	Rent:	  	€17.75/m2 (excl. VAT) per month; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	5th ADDENDUM:	  	06/04/2014 [sic: 06/30/2014]
		
	Parking spaces:	  	1 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€104.31 (excl. VAT) per parking space per month for the additional parking space; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	6th ADDENDUM:	  	08/13/2014
		
	Parking spaces:	  	1 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€104.31 (excl. VAT) per parking space per month for the additional parking space; payment of ancillary charges: €2.90/m2 (excl. VAT) per month
		
	7th ADDENDUM:	  	
		
	Parking spaces:	  	1 additional (on the 1st basement level)
		
	Term:	  	as before
		
	Rent:	  	€104.31 (excl. VAT) per parking space per month for the additional parking space; payment of ancillary charges: €2.90/m2 (excl. VAT) per month

  
  

 3 
  

 

			
	 Calculation of charges
 by Wüstenrot
Marxbox GmbH & Co. OG
 Percentage fee: €58.84
 Date of
the calculation:
  
 Vienna, on ______________
	  	 CALCULATION BILLING

Tax No.: 042 / 9505
  

Serial No.: 33 for 10/14
  

Charges: €58.84
  

Building Management Frieda Rustler

1150 Vienna, Mariahilfer Straße 196

		
	Wüstenrot Marxbox GmbH & Co. OG	  	

 7th ADDENDUM

 TO THE LEASE AGREEMENT OF 11/26/2010 

entered into by 
 Wüstenrot Marxbox
GmbH & Co. OG 
 domiciled in Vienna 

(FN 346428d Regional Court Salzburg) 

5033 Salzburg, Alpenstraße 61 
 referred
to in the following as the Landlord, on the one hand, and 
 ARSANIS Biosciences GmbH 

domiciled in Vienna 
 (FN
354305m Commercial Court Vienna) 
 1030 Vienna, Helmut Qualtinger Gasse 2 

referred to in the following as the Tenant, on the other hand, as follows: 
  

	1.	The contracting parties entered into a Lease Agreement (Attachment ./1) on 11/26/2010, a 1st Addendum (Attachment ./2) on 08/31/2012, a 2nd Addendum (Attachment ./3) on 10/09/2012, a 3rd Addendum (Attachment ./4) and a
4th Addendum (Attachment ./5) on 06/04/2014, a 5th Addendum (Attachment ./6) on 06/30/2014 and a 6th Addendum to the Lease Agreement (Attachment ./7) on 08/13/2014, which constitute integral components of this 7th Addendum, for rented
areas or parking spaces in the building on the property EZ 4359, Land Register 01006 Landstraße, District Court Inner City Vienna, consisting of Lot No. 1449/3, with the address 1030 Vienna, Helmut Qualtinger Gasse 2. 

 

	2.	The contracting parties have now agreed that, in addition to the premises and parking spaces already included in accordance with Attachments ./1 to ./7, the Tenant will lease from the Landlord an
additional parking space on the 1st basement level of the building identified in Item 1. 

  

 4 
  

 

	3.	The tenancy for the additional parking space begins with the transfer and acceptance of the rental property in accordance with Item 2 of this 7th Addendum to the
Lease Agreement. 

  

	4.	The monthly rent for the additional parking space in accordance with Item 2 of this 7th Addendum to the Lease Agreement is €104.31 (excl. VAT) per parking
space. Pending further assessment by the Landlord, the monthly payment of ancillary charges for the parking spaces is €2.90 (excl. VAT) per m2 useable area. 

 

	5.	This 7th Addendum to the Lease Agreement supplements the understanding entered into by the parties with the Lease Agreement of 11/26/2010, as well as with the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum and the 4th Addendum of 06/04/2014, the 5th Addendum of 06/30/2014 and the 6th Addendum of 08/13/2014 to
the Lease Agreement. The rented areas identified in the Lease Agreement of 11/26/2010, in the 1st Addendum of 08/31/2012, in the 2nd Addendum
of 10/09/2012, in the 3rd Addendum of 06/04/2014, in the 4th Addendum, likewise of 06/04/2014, in the 5th Addendum of 06/30/2014 and in the 6th Addendum to the Lease Agreement of 08/13/2014 and the additional parking space identified under Item 2
in this 7th Addendum to the Lease Agreement together constitute the rental property. 

  

	6.	Insofar as this 7th Addendum to the Lease Agreement does not state explicit modifications, the other provisions of the Lease Agreement of 11/26/2010, the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum and the 4th Addendum of 06/04/2014, the 5th Addendum of 06/30/2014 and the 6th Addendum of 08/13/2014
remain in effect. The Lease Agreement of 11/26/2010, the 1st Addendum of 08/31/2012, the 2nd Addendum of 10/09/2012, the 3rd Addendum of 06/04/2014, the 4th Addendum, likewise of 06/04/2014, the 5th Addendum of
06/30/2014, the 6th Addendum of 08/13/2014 and this 7th Addendum to the Lease Agreement are therefore one integrated contract.

  

	7.	Any fees incurred in connection with the finalization of this 7th Addendum to the Lease Agreement shall be borne by the Tenant, who in this respect indemnifies
and holds the Landlord completely harmless. 

  

	8.	This 7th Addendum to the Lease Agreement is executed in two copies, of which each contracting party shall receive one. 

  

 5 
  

 

					
	Attachments:	  	./1	  	Lease Agreement of 11/26/2010
		  	./2	  	1st Addendum to the Lease Agreement of 08/31/2012
		  	./3	  	2nd Addendum to the Lease Agreement of 10/09/2012
		  	./4	  	3rd Addendum to the Lease Agreement of 06/04/2014
		  	./5	  	4th Addendum to the Lease Agreement of 06/04/2014
		  	./6	  	5th Addendum to the Lease Agreement of 06/30/2014
		  	./7	  	6th Addendum to the Lease Agreement of 08/13/2014

 Vienna, on Sep. 30, 2014 
  

			
	 Wüstenrot Marxbox GmbH & Co. OG

WV Immobilien GmbH
	  	 ARSANIS

Biosciences GmbH
 MarxBox

Helmut Qualtinger Gasse 2
 1030
Vienna

		
	 /s/ GF Mag. Wolfgang Schantl     /s/ Josef Millonigg
	  	 /s/ Dr. Eszter Nagy

	Wüstenrot Marxbox GmbH & Co. OG	  	ARSANIS Biosciences GmbHEX-10.18

 Exhibit 10.18 

Confidential Materials omitted and filed separately with the 

Securities and Exchange Commission. Double asterisks denote omissions. 

CONFIDENTIAL 
 EXECUTION
COPY 
 COLLABORATION AGREEMENT 

THIS COLLABORATION AGREEMENT (the “Agreement”) is made as
of the date the later- signing party signs this Agreement (“Signing Date”), to have effect retroactive to May 1, 2011 (the “Effective Date”), by and between ADIMAB,
LLC, a Delaware limited liability company having an address at 16 Cavendish Court, Lebanon, NH 03766 (“Adimab”) and ARSANIS, INC., a Delaware
corporation having an address at 16 Cavendish Court, Lebanon, NH 03766 (together with Arsanis Biosciences GmbH, an Austrian entity having an address at Helmut-Qualtinger-Gasse 2, Vienna, A-1030, Austria, collectively “Arsanis”).

 BACKGROUND 

1. Adimab is the leader in yeast-based, fully human antibody discovery using its proprietary core technology platform. 

2. Arsanis is a newly formed biotechnology company focused on and having great expertise in infectious disease-related biological
targets. 
 3. The Parties wish to collaborate to have Arsanis select infectious disease-related biological targets; Adimab
discover antibodies directed against the selected targets; and Arsanis determine the activity of the antibodies delivered by Adimab and have the option to license certain of these antibodies for development and commercialization as biopharmaceutical
product(s), all as more particularly set forth in this Agreement. 
 NOW, THEREFORE, in
consideration of the foregoing premises and the mutual covenants set forth below, and for other good and valuable consideration, the receipt of which is hereby acknowledged, Adimab and Arsanis hereby agree as follows: 

ARTICLE 1  
 DEFINITIONS.

 The following initially capitalized terms have the following meanings (and derivative forms of them shall be interpreted
accordingly): 
 1.1 “Accounting Standards” means United States generally accepted accounting principles, or International
Financial Reporting Standards, whichever is used by the applicable Party in preparing its audited financial statements, in either case, consistently applied. 

 1.2 “Adimab Change of Control” shall have the
same meaning as in the definition of Arsanis Trade Sale, applying such definition mutatis mutandis to Adimab in the same way that it applies to Arsanis. 

1.3 “Adimab Materials” means any tangible biological or chemical materials (including all [**] and other [**] in the
form of tangible biological or chemical materials) provided by Adimab to Arsanis under a Research Program, [**]. 
 1.4
“Adimab Platform/Background Patents” means all Patents [**] the [**] that [**], not [**] the [**] on the basis of the [**] in which [**] under the [**]. 

1.5 “Adimab Platform/Core Technology” means [**] and [**] that [**] and [**] in the [**] and [**] of [**] of the
[**]. 
 1.6 “Adimab Platform/Core Technology Improvement” means all [**] and [**] (and Patents claiming
them) [**], including any and all [**] or [**] to Adimab Platform/Core Technology as it is practiced by Adimab as of the Effective Date. Antibody Sequence Coverage shall not be deemed Adimab Platform/Core Technology Improvements. Adimab
Platform/Core Technology Improvements do not include Broad Non-CDR Antibody Inventions (which, to avoid doubt, in accordance with the definition thereof, do not encompass any Program Inventions of which Adimab is an inventor in whole or in part).

 1.7 “Adimab Program Antibody Know-How” means all Know-How Controlled by Adimab [**] that [**] for Arsanis
[**] or [**] Program Antibodies as provided for in a Research Plan, (b) [**], or (c) [**]. The Adimab Program Antibody Know-How excludes [**] that is used [**] or [**] than the [**] of the foregoing sentence, but explicitly includes —
to the extent actually disclosed by Adimab to Arsanis under this Agreement, and without implying any such disclosure obligation — any Know-How necessary for Arsanis to modify or create derivative forms of a Program Antibody as contemplated by
the definition of “Product”. The Parties do not intend for Arsanis to obtain under this Agreement the ability or right to practice the Adimab Platform/Core Technology for antibody discovery purposes. 

1.8 “Adimab Program Antibody Patents” means any and all Program Antibody Patents the invention of which is an Adimab
Program Invention. 
 1.9 “Adimab Program Inventions” means all Program Inventions for which Adimab (or its
Affiliate) has (meaning that it employs or has engaged as a consultant) at least one (1) person who would be a properly named inventor on the U.S. Patent claiming such invention, other than Joint Program Inventions. Inventorship for purposes of
this definition, and all intellectual property-related definitions in this Agreement, shall be determined in accordance with United States patent law, 

1.10 “Affiliate” means, as to a given entity, another entity that, directly or indirectly, through one or more
intermediaries, controls, is controlled by or is under common control with a such first entity. For purposes of this definition, “control” means the ownership of fifty percent (50%) or more of the voting securities entitled to elect
the directors or management of the entity, or the actual power to elect or direct the management of the entity. An Affiliate of Arsanis shall mean an entity that is an Affiliate of either (or both) of the entities collectively defined as 

  
 2 

 
Arsanis (i.e., that is an Affiliate of either or both of Arsanis, Inc. and Arsanis Biosciences GmbH). Adimab and Arsanis shall not be deemed to be Affiliates of each other, nor shall
Affiliates of Arsanis be deemed to be Affiliates of Adimab (due to a common control relationship), or vice versa. Moreover, notwithstanding anything in this Agreement to the contrary, any venture capital fund, private equity fund or other
investor who is not primarily an operating biopharmaceutical, pharmaceutical, diagnostics, or medical device research and development and/or marketing company (a “Non-affiliate Investor”) shall not be considered an Affiliate of
Arsanis, and any person or entity that directly or indirectly controls or is controlled by a Non-affiliate Investor (except for any entity directly or indirectly controlled by Arsanis, controlling Arsanis, or under common control with Arsanis, in
each case other than through Non-affiliate Investor(s)) shall not be considered an Affiliate of Arsanis solely by reason of being controlled by the same Non-affiliate Investors. The foregoing sentence shall apply mutatis
mutandis to Adimab. 
 1.11 “Antibody Sequence Coverage” means a Program Patent with respect to
which all of the following clauses (a) through (c) apply: (a) includes independent claim(s) to the composition of matter of a Program Antibody, which claims recite as a claim limitation the sequence, in whole or in part, of the
Program Antibody’s CDR (whether in amino acid or nucleic acid format), whether or not including a homology range or permitted level of substitution or variance (or specific substitutions, variations or positions for placement of substitutions
or variations) from, to or within such sequence; (b) may also include other independent claim(s) reciting such a claim limitation and directed to the use or formulation of a Program Antibody; and (c) does not include any independent
claim(s) not described by (a) or (b). Adimab shall be entitled to require separate filings in order to separate claims that standing alone would be Antibody Sequence Coverage from other claims that standing alone would be either Adimab
Platform/Core Technology Improvements, Epitope Patents or Patents on Broad Non-CDR Antibody Inventions. 
 1.12
“Arsanis Materials” means any tangible biological or chemical materials (including antigen samples and other Know-How in the form of tangible biological or chemical materials) provided by Arsanis to Adimab under any Research
Program. 
 1.13 “Arsanis Program Antibody Patent” means any Program Antibody Patent the invention of which
is an Arsanis Program Invention. 
 1.14 “Arsanis Program Inventions” means all Program Inventions for which
Arsanis (or its Affiliate) has (meaning that it employs or has engaged as a consultant) at least one (1) person who would be a properly named inventor on the U.S. Patent claiming such invention, other than Joint Program Inventions. Inventorship
for purposes of this definition, and all intellectual property-related definitions in this Agreement, shall be determined in accordance with United States patent law. 

1.15 “Arsanis Trade Sale” means any transaction, or series of related transactions, that is, or are, (x) an
“Event” as defined in the Certificate of Incorporation of Arsanis as it exists as of the signing date, as reproduced in Exhibit G, except that no vote of any shareholder or class of shareholders shall be required for any transaction or
series of transactions to qualify as an “Event;” or (y) other sale of Arsanis or an Affiliate holding rights under or to this Agreement to 

  
 3 

 
any Third Party(ies), regardless of the form of the transaction(s), and including sale of stock and sale of majority “control” (as described in the definition of Affiliate), whether or
not involving the issuance of new shares, unless: (a) the business of Arsanis immediately prior to such transaction(s) is the primary business of Arsanis or the surviving entity immediately after such transaction(s); and (b) Arsanis or the
surviving entity, immediately after such transaction(s), is controlled (as “control” is defined in the definition of Affiliate), directly or indirectly, through zero, one or more intermediaries, exclusively by any one or more venture
capital funds, private equity funds or other investors each of whom is not primarily an operating biopharmaceutical, pharmaceutical, diagnostics, or medical device research and development and/or marketing company and is not controlled (as
“control” is defined in the definition of Affiliate) by such an operating company. Notwithstanding anything express or implied in this definition, if Arsanis becomes Affiliated with any top-[**] (based on annual sales) pharmaceutical or
top-[**] (based on annual sales) biopharmaceutical company, regardless of the form of the transaction(s) and which entity is the surviving entity, this shall be an Arsanis Trade Sale for purposes of this Agreement. 

Notwithstanding anything express or implied in this definition, Arsanis Trade Sale excludes Subsidiary Trade Sales. 

1.16 “Broad Non-CDR Antibody Invention” means any Arsanis Program Invention that (a) that has general application
to antibodies regardless of CDR or relates solely to the constant region of antibodies, (b) is not in any way specific to the CDR of any Program Antibody or Program-Benefited Antibody, and (c) is not claimed in a Patent claim that recites
the sequence of all or any portion of such CDR in an independent claim, whether or not including a homology range or permitted level of substitution or variance (or specific substitutions, variations or positions for placement of substitutions or
variations) from, to or within such sequence. 
 As non-limiting examples, the following inventions would qualify as Broad Non-CDR
Antibody Inventions if they were Arsanis Program Inventions: Fc modifications; chemistry or sequences for conjugating antibody constant regions to toxins or other drugs; sites, amino acid sequences and methods for creating fusion proteins of
antibodies with other proteins, diagnostic assays (the non-pretextual independent claims of which are not limited by CDR in the manner described in clause (c) of the foregoing paragraph) and identification of biomarkers (the non- pretextual
independent claims of which are not limited by CDR in the manner described in clause (c) of the foregoing paragraph). 
 Subject to the
confidentiality and sequence non-disclosure provisions of this Agreement, a Patent claiming Broad Non-CDR Antibody Inventions may recite a Program Antibody or Program-Benefited Antibody as an example, and this fact alone shall not cause the claimed
invention not to be a Broad Non-CDR Antibody Invention, as long as it meets the requirements of (a) - (c) in the first sentence of this definition. 

1.17 “Business Day” means a day that is not a Saturday, Sunday or public holiday in Vienna, Austria or Lebanon, New
Hampshire, USA. 
 1.18 “CDR” means the complementarity-determining region of an antibody. 

  
 4 

 1.19 “Collaboration” means each Party’s activities under or in
connection with a Research Program at any time during the Collaboration Term. 
 1.20 “Collaboration Term”
means the period starting on the Effective Date and continuing until the later of (a) expiration of the Tail Period or (b) completion of any Research Program activities continuing thereafter. 

1.21 “Combination Product” means: 

(a) a pharmaceutical composition that contains or is comprised of one or more Licensed Antibody(ies), and additionally contains or is
comprised of one or more clinically active therapeutic or prophylactic ingredients that are not Licensed Antibody(ies) (“Drug Combination”); 

(b) a therapeutic or prophylactic Product (whether or not a Drug Combination) that is delivered by a proprietary, patented delivery
device licensed from a Third Party, where the therapeutic or prophylactic Product and the patented delivery device are sold together for a single sales price (“Drug-Device Combination”); or 

(c) a diagnostic Product that contains or is comprised of one or more Licensed Antibody(ies), and additionally contains or is comprised
of one or more other antibodies that are not Licensed Antibody(ies) and/or also includes one or more other patented technology(ies)that is or are royalty-bearing to any Third Party. 

1.22 “Commercially Reasonable Efforts” has the meaning given in Section 3.4(a). 

1.23 “Confidential Information” has the meaning given in Section 6.1. 

1.24 “Control” means, with respect to any Know-How or Patent, [**]other than pursuant to this Agreement[**] of the
[**] or other right as provided for in this Agreement without violating the terms of any written agreement with any Third Party. 

1.25 “Cover” means, with respect to a particular item and a particular Patent, that such Patent claims or covers, in
any of the countries of manufacture, use, and/or sale, [**] of [**] of [**] or [**] or [**] or [**] of [**] of [**] of the [**] and/or [**] or [**]. 

1.26 “Epitope Patent” means any Patent owned or Controlled by Arsanis or its Affiliate that is directed exclusively to
any invention that relates to any epitope of a Target, including by being a method specifically involving such epitope (including any therapeutic, prophylactic or diagnostic use of such epitope), which invention is a Program Invention or is invented
using (a) Program Know-How as to such epitope or (b) Program Antibodies or Program-Benefited Antibodies that bind to such epitope. Epitope Patents include Patents directed to inventions expressed in terms of claiming antibodies that bind
to the applicable epitope, based on their binding characteristics defined functionally or by reference to their interaction with the epitope, rather than specifically by binding sequence. Epitope Patents exclude Antibody Sequence Coverage.

 1.27 “Field” means all therapeutic, prophylactic and diagnostic uses in humans. 

  
 5 

 1.28 “First Commercial Sale” means, with respect to a Product in any
country, the first sale, transfer or disposition for value or for end use or consumption of such Product in such country after Marketing Authorization has been received in such country. 

1.29 “Full Time Equivalent” or “FTE” means the equivalent of a full-time scientist’s working
days over a twelve (12) month period (taking account of normal vacations, sick days and holidays not being considered working days), which equates to a total of [**] hours per twelve (12) month period of scientific work performed by a
fully qualified Adimab employee or consultant directly in the Collaboration. To provide an FTE over a given time period that is less than a year means to provide the proportionate share (corresponding to the proportion that such time period bears to
a full year) during such time period of a full year’s FTE. In no event shall the work over the course of a year of one individual person account for more than one (1) FTE year. 

1.30 “FTE Rate” means [**] dollars ($[**]) per FTE (or [**] dollars ($[**]) on a quarterly basis). 

1.31 “Joint Inventions” means any and all Program Inventions for which Adimab (or its Affiliate) and Arsanis (or its
Affiliate) each have (meaning that each employs or has engaged as a consultant) at least one (1) person who would be a properly named inventor on the U.S. patent claiming such invention. Inventorship for purposes of this definition, and all
intellectual property-related definitions in this Agreement, shall be determined in accordance with United States patent law. 

1.32 “Joint Program Antibody Patent” means any Program Antibody Patent the invention of which is a Joint Invention.

 1.33 “Joint Serendipitous Inventions” means all Joint Inventions other than those claimed by Joint Program
Antibody Patents or constituting Adimab Platform/Core Technology Improvements or inventions claimed in Antibody Sequence Coverage or Epitope Patents. 

1.34 “Know-How” means all technical information and know-how, including inventions, discoveries, trade secrets,
specifications, instructions, processes, formulae, materials (including cell lines, vectors, plasmids, nucleic acids and the like), methods, protocols, expertise and other technology applicable to formulations, compositions or products or to their
manufacture, development, registration, use or marketing or to methods of assaying or testing them or processes for their manufacture, formulations containing them or compositions incorporating or comprising them, and including all biological,
chemical, pharmacological, biochemical, toxicological, pharmaceutical, physical and analytical, safety, quality control, manufacturing, preclinical and clinical data, instructions, processes, formula, and expertise. 

1.35 “Licensed Antibody” has the meaning given in Section 3.2. 

1.36 “Licensed Program Antibody Patents” means those Program Antibody Patents that Cover Licensed Antibodies.

 1.37 “Major Market” means any of the [**]. 

  
 6 

 1.38 “Marketing Authorization” means all approvals from the relevant
Regulatory Authority necessary to market and sell a product (including a Product) in any country, including a Biologics License Application (BLA) in the U.S. 

1.39 “Multi-Product Deal” means a Program Transaction in which rights are granted to one or more Licensed Antibodies
and/or Products, and one or more antibodies, drugs and/or products that (a) are not Licensed Antibodies and/or Products, (b) are not (and are not based on) Program-Benefited Antibodies, and (c) are directed against or involve one or
more Targets that are not Unrelated Targets with respect to the particular Program Transaction. A Multi-Product Deal may or may not also be a Multi-Target Deal. 

1.40 “Multi-Product Deal Program Transaction Revenue” means, in a Multi- Product Deal, the portion of the Program
Transaction Revenue for that Multi-Product Deal that is allocated and designated as Multi-Product Deal Program Transaction Revenue as provided in Section 4.3(c) (including via its reference to Section 10.2(b)). 

1.41 “Multi-Target Deal” means a Program Transaction that includes rights to products the only antibodies in which are
antibodies to targets considered Unrelated Targets with respect to such Program Transaction (and are not Licensed Antibodies or Program-Benefited Antibodies), in addition to including rights to Products. A Program Transaction shall not be considered
a Multi-Target Deal solely because it includes a Combination Product for which one active ingredient is targeted to a target that is considered an Unrelated Target in that Program Transaction. Instead, the intent of the Parties in the
“Multi-Target Deal” definition is to capture the situation where Arsanis or its Affiliate grants rights to multiple programs to the same counterparty, and at least one of the programs does not relate to Targets or does not include Program
Antibodies or Program-Benefited Antibodies. 
 1.42 “Multi-Target Deal Program Transaction Revenue” means,
for a Multi-Target Deal, the portion of the Program Transaction Revenue for that Multi-Target Deal that is allocated and designated as Multi-Target Deal Program Transaction Revenue as provided in Section 4.3(d) (including via its reference to
Section 10.2(b)). 
 1.43 “Net Sales” means the gross amount invoiced by Arsanis or its Affiliates, or their
Program Transaction counterparties (or their Affiliates) in Program Transactions for which the Royalty Election is made, for the sale, transfer or other disposition of Product to other Third Parties (in final form for end use or in whatever form is
sold to Third Parties who are not Program Transaction counterparties (or their Affiliates)), less any of the following applicable deductions to the extent actually granted and included in the invoiced amounts: 

[**]. 
 Even if
there is overlap between any of deductions [**], each individual item shall only be deducted once in each Net Sales calculation. 
 Net
Sales calculated as described above shall be adjusted for Combination Products, as provided in Section 4.5(c). The same adjustment shall be applied to product bundles (in the countries where bundling is permitted under anti-trust law, if any).

  
 7 

 Net Sales excludes amounts from sales or other dispositions of Product between Arsanis and any of
its Affiliates, and Program Transaction counterparties (and their Affiliates), solely to the extent that such entity purchasing a Product either (a) resells such Product to another Third Party not Affiliated with any of them and such resale is
included in Net Sales, or (b) the quantities are for use to be provided free to patients in a Product clinical trial. 
 1.44
“Option” means, for each Target, Arsanis’ option for that Target as described in Section 3.2. 
 1.45
“Option Evaluation Period” means, with respect to a Target and the Program Antibodies to such Target, the period commencing with the first day of the applicable Option Term and ending on the earlier of (a) the date of
Option exercise or (b) the expiration the Option Term. 
 1.46 “Option Term” means, for each Target, the
time period beginning at the end of the Research Term for that Target, and continuing for [**] months thereafter. 
 1.47
“Party” means Adimab or Arsanis. 
 1.48 “Patent” means any patent application or patent
anywhere in the world, including all of the following kinds: provisional, utility, divisional, continuation, continuation-in-part, and substitution applications; and utility, re-issue, re-examination, renewal and extended patents, and patents of
addition, and any Supplementary Protection Certificates, restoration of patent terms and other similar rights. 
 1.49
“Payment Patent” means any (a) Licensed Program Antibody Patent (to avoid doubt, these by definition are not directed to Broad Non-CDR Antibody Invention(s)), and (b) Epitope Patents. 

1.50 “Product” means any device, biologic or drug (or investigational device, biologic or drug) for use in the Field
that [**], or (b) [**] or [**], (ii) [**], (iii) [**], and (iv) [**]. 
 Products include Combination Products,
however, this inclusion shall not be read to provide a license for any antibody or other active ingredient or component in a Combination Product that is not a Licensed Antibody (“Unlicensed Other Ingredient”), under independent
intellectual property (including Patents and Know-How) of Adimab or its Affiliate Covering or with respect to the Unlicensed Other Ingredient on a stand-alone basis apart from its inclusion in the Combination Product. The same principle shall apply
to exclude proprietary devices and diagnostic methods of Adimab and its Affiliates that do not constitute Adimab Platform/Background Patents and are not Program Inventions. 

1.51 “Program Antibody” means each antibody [**] and [**] to Arsanis under a Research Program. For this purpose, [**]
may occur through [**] of a Program Antibody refers interchangeably, and throughout this Agreement, to the [**]. 
 1.52
“Program Antibody Patents” means Program Patents that [**] a Program Antibody or product containing a Program Antibody; [**] do not [**]; and [**] are not Epitope Patents. 

  
 8 

 1.53 “Program-Benefited Antibody” has the meaning given in Section
3.5(a). 
 1.54 “Program Inventions” means any patentable invention that is conceived and/or first reduced to
practice in whole or in part by employees, contractors or agents of either Party or of both Parties in the course of the Collaboration or the evaluation of a Program Antibody during the applicable Option Evaluation Period. 

1.55 “Program Know-How” means all Know-How made, developed, invented or discovered by employees, contractors or agents
of either Party or of both Parties in the course of the Collaboration or the evaluation of a Program Antibody during the applicable Option Evaluation Period, excluding Program Inventions claimed in any Program Patent that has published or issued,

 1.56 “Program Patent” means any Patent claiming a Program Invention. 

1.57 “Program Trade Sale Proceeds” has the meaning given in Section 4.3(b). 

1.58 “Program Transaction” means any and all agreements, transactions or arrangements that include a grant by Arsanis
or its Affiliate(s) to any Third Party of rights of any kind with respect to any Payment Patent(s), Licensed Antibody(ies) and/or Product(s), regardless of the form of transaction, including asset sales, assignments, licenses, covenants not to sue,
grants of distribution rights, Subsidiary Trade Sales and options for any of the foregoing. Program Transactions exclude, however, (a) an Arsanis Trade Sale and any such transactions entered into by Arsanis or its successor after, and that do
not form any part of (i.e. do not form part of a series of transactions constituting), an Arsanis Trade Sale, and (b) agreements with contract manufacturing organizations (CMOs), contract research organizations (CROs), academic research
organizations (AROs) and other contractors, or academic, non-profit or governmental entities, in each case where (1) the agreement counterparty is performing services for or collaborating with Arsanis or its Affiliates and the counterparty and
its Affiliates are not granted any commercialization rights of any kind with respect to any Payment Patent(s), Licensed Antibody(ies) and/or Product(s) (including options for commercial rights) (whether pursuant to the same or under a different
agreement) and (2) no revenue will be received by Arsanis or any of its Affiliates. 
 If multiple related or reasonably
contemporaneous agreements, transactions or arrangements with any given Third Party (or set of related or affiliated Third Parties) are entered into by Arsanis or its Affiliate (or any combination of them), and one such agreement, transaction or
arrangement would alone be a Program Transaction, then all such related or reasonably contemporaneous agreements, transactions or arrangements shall together be considered a single Program Transaction. As a non-limiting example, if Arsanis were to
enter into one agreement with a Third Party for a commercialization license for a Licensed Antibody under Licensed Program Antibody Patents, another agreement with that Third Party with respect to clinical data generated by or for Arsanis with
respect to a Licensed Antibody Covered by such Patents, a further agreement with such Third Party for other antibodies or small molecules acting via the same Target, and another agreement with an affiliate of that Third Party for Target-related
intellectual property on that same Target, then all four agreements together constitute a single Program Transaction for purposes of this Agreement, including for purposes of the definition of Program Transaction Revenue associated with such Program
Transaction. As another non-limiting example, this includes a Multi-Product Deal (but there is a special Program Transaction Revenue determination for Multi-Product Deals, set forth in Section 4.3(c)). 

  
 9 

 1.59 “Program Transaction Revenue” means all consideration (including
monetary and non-monetary consideration in all forms other than not-readily-monetizable covenants that are customary in out-licensing deals in which the out-licensor is not obtaining rights to any unrelated intellectual property or products of the
licensee, as further described in the last paragraph of this definition) actually received by Arsanis or its Affiliate or shareholders in either of them, from any Third Party in connection with a Program Transaction, excluding only: 

(a) research and development reimbursement for research and development to be performed after the date of the Program Transaction,
accounted for at reasonable and customary rates, on a full time equivalent basis (any excess over a reasonable and customary FTE rate is included in Program Transaction Revenue) or in the form of external costs billed through on a pass-through basis
with no markup; 
 (b) reimbursement of patent expenses on a pass-through basis with no markup (to avoid doubt, this
explicitly excludes payments to Adimab under Article 4); 
 (c) payments for equity of Arsanis to the extent at fair market
value (the amount of any premium is included in Program Transaction Revenue); 
 (d) proceeds of repayable loans that are not
forgiven (if later forgiven, the amount of the forgiven debt is included in Program Transaction Revenue); 
 (e) payments for
supply of Product to the extent at Arsanis’ (or its Affiliate’s) fully burdened manufacturing cost (any excess over the fully burdened cost is included in Program Transaction Revenue); and 

(f) research and development funding from governmental or non-profit entities to the extent required to be spent on research and
development occurring after the date the Program Transaction is signed. 
 Other than in the case of a Multi-Target Deal or a
Multi-Product Deal (which shall be handled as provided for in Section 4.3(c) or (d), as applicable), there shall be no adjustment, proportionality or scaling of any kind to or of Program Transaction Revenue for the inclusion, in addition to
Program Know-How or Licensed Program Antibody Patents, of other intellectual property or rights in the Program Transaction (e.g., clinical data or trademarks in addition to Licensed Program Antibody Patents); provided, however, that in
the case of a Combination Product, the allocation of Program Transaction Revenue shall be subject to further potential adjustment under Section 4.3(e). 

If Arsanis receives Program Transaction Revenue in a form other than immediately available funds (for example, in equity of a Third Party),
then Adimab shall receive its share of the Program Transaction Revenue in the same forms and in the same proportions as does Arsanis (i.e., Adimab will receive its share in the same mix of immediately available funds and in-kind consideration as
Arsanis), or if the Parties agree on a case-by-case basis that such an in-kind 

  
 10 

 
distribution is not practical, then Arsanis shall pay Adimab’s share, calculated based on the fair market value of such in-kind consideration, in cash or wire transfer of immediately
available funds. If the Parties do not agree that the in-kind distribution is not practical, then Adimab shall have the right to decline and forgo its share of in-kind consideration on a case-by-case basis. For clarity, if Program Transaction
Revenue is subject to increase by contingent payments related to future events and/or release of escrowed amounts, such increased amounts shall be included as Program Transaction Revenue only as and when such payments are received by Arsanis (or its
Affiliate or shareholders in Arsanis or its Affiliates). 
 The following types of consideration in a Program Transaction are not considered
and shall be deemed excluded from Program Transaction Revenue: covenants of diligent development and commercialization; representations and warranties; confidentiality and non-use commitments; customary indemnification provisions; reversionary
rights to the licensed products in case of agreement termination (in whole or in part); grantbacks of intellectual property with respect to the licensed product, for a retained territory or otherwise; operational commitments (e.g., to provide
reports, to participate in joint committees, etc.); and similarly non-monetizable covenants that are customary in out-licensing transactions in which the out-licensor is not obtaining rights to any unrelated intellectual property or products of the
licensee – and to avoid doubt explicitly excluding product quids. 
 1.60 “Regulatory Authority” means the FDA
or any counterpart of the FDA outside the United States. 
 1.61 “Research Committee” has the meaning given
in Section 2.1(a). 
 1.62 “Research Overview” means the diagram attached at Exhibit B. 

1.63 “Research Plan” means the research plan set forth in Exhibit C, or any research plan providing for a program of
research that the Research Committee may finalize and the Parties approve in writing as provided for in Section 2.2. It is anticipated that there may ultimately be [**] Research Plans under the Collaboration, but the final number of Research
Plans is not currently known. The Research Plan of Exhibit C is “Research Plan 1.” All subsequent Research Plans will be numbered consecutively. All Research Plans shall comply with the applicable requirements stated in Section 2.2.

 1.64 “Research Program” means a program of research conducted under this Agreement in accordance with a
Research Plan. Research Program 1 is the program of research under Research Plan 1. Each Research Program shall have the same number as the Research Plan to which it corresponds. 

1.65 “Research Term” means, for each Research Program, the period beginning when Arsanis first delivers Arsanis
Materials under such Research Program to Adimab, and ending when Adimab completes the activities called for under the Research Plan for that Research Program. 

1.66 “Revenue Election” has the meaning given in Section 4.3(a). 

1.67 “Royalty Election” has the meaning given in Section 4.3(a). 

  
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 1.68 “Royalty Term” has the meaning given in Section 4.5(b), 

1.69 “Senior Executives Discussions” has the meaning given in Section 10.2(a). 

1.70 “Start Date” means the date that Adimab designates in writing to Arsanis as the date upon which the Adimab
campaign team will start the first Research Program under this Agreement. Adimab shall provide this written designation to Arsanis within [**] weeks after the Signing Date. 

1.71 “Subsidiary Trade Sale” means, with regard to any subsidiary Affiliate of Arsanis that does not hold or have the
right to obtain all or substantially all of the Undesignated Rights under this Agreement, any transaction, or series of related transactions, that would constitute an Arsanis Trade Sale if the name of the subsidiary Affiliate was substituted for the
name of Arsanis in the definition of Arsanis Trade Sale. 
 1.72 “Success Criteria” shall mean, for each
Research Program, the criteria set forth in the applicable Research Plan for the characteristics that are being sought in the Program Antibodies to the corresponding Target, as a group. Success Criteria may be defined with respect to a population of
antibodies, such that some specified number (less than all) of the Program Antibodies delivered by Adimab may be required to meet different criteria, and in that case if the population of Program Antibodies collectively meet those criteria (by the
minimum numbers of individual antibodies meeting different of the articulated criteria set forth in the applicable Research Plan), then the Success Criteria shall be deemed met. 

1.73 “Tail Period” means the [**] months beginning at the end of the Target Nomination Period. 

1.74 “Target” means the disease-related biological target of interest to Arsanis that is specifically identified in
Research Plan 1, or the disease-related biological target of interest to Arsanis that is specifically identified in any subsequent Research Plan. Different epitopes on or serotypes of the same molecule that is a biological target of interest will
not be deemed to be different Targets, and Target shall be defined by reference to entire molecules rather than individual serotypes/epitopes (although activities may be focused on specific serotype/epitopes). 

1.75 “Target Nomination Period” means the period beginning on the Start Date and ending on December 31, 2012.

 1.76 “Third Party” means an entity other than a Party or the Affiliate of a Party. 

1.77 “Undesignated Rights” means those commercial rights in and to a Licensed Antibody (and/or the Products comprised
of such Licensed Antibody) as to which a Revenue Election or Royalty Election has not previously been made (e.g., with respect to particular jurisdictions, indications and/or fields of use). 

1.78 “Unrelated Target” means, in any given Program Transaction, any biological target (a) that is
not a Target, or (b) that is a Target, but for which Target no Licensed Antibodies, Program-Benefited Antibodies or Epitope Patents are included in the given Program Transaction. 

  
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 1.79 References in the body of this Agreement to “Sections” refer to the
sections of this Agreement. The terms “include,” “includes,” “including” and derivative forms of them shall be deemed followed by the phrase “without limitation” regardless of whether such phrase appears there
(and with no implication being drawn from its inconsistent inclusion or non-inclusion). 
 1.80 To avoid doubt, the term
“antibody” as used everywhere else in this Agreement includes both full-length antibodies, fragments thereof, and chemically modified versions thereof (including pegylated versions and regardless of whether containing amino acid
substitutions), all of the foregoing whether naturally occurring, artificially produced, raised in an artificial system, or created through modification of an antibody produced in any of the foregoing ways or otherwise. 

ARTICLE 2
 PROGRAM.

 2.1 Scientific Research Committee. 

(a) Research Committee. Promptly after the Signing Date, the Parties shall form a steering committee consisting of [**] representatives
from each Party (the “Research Committee”). Adimab’s initial members of the Research Committee shall be [**]. Arsanis’ initial such members shall be [**]. Either Party may change its Research Committee members upon written
notice to the other Party. 
 (b) Meetings. The Research Committee shall hold its first meeting within [**] days after the
Signing Date. Thereafter, it shall meet from time to time promptly after the date of a written request by either Party, and in any event no less frequently than [**] during the Collaboration Term. The Research Committee may meet in person or by
teleconference or videoconference. Each Party shall designate one of its Research Committee members as co-chair. The co-chairs shall be responsible to circulate a written agenda in advance of each Research Committee meeting. The co-chairs shall be
responsible to circulate, finalize and agree in writing on minutes of each meeting within [**] days after the meeting date. Each Party shall be entitled to have a reasonable number of its employees and consultants who are not Research Committee
members attend Research Committee meetings from time to time; provided, that such employees and consultants are subject to written confidentiality and non-use obligations that are no less stringent than the confidentiality
obligations and restrictions on use set forth in Article 6. 
 (c) Responsibilities. The Research Committee’s role is to
(i) facilitate communication regarding progress and results under the Collaboration and as to individual Research Programs; (ii) review and discuss reports provided by each Party; (iii) be the working group that will prepare and
finalize new proposed research plans for approval by each Party; (iv) prioritize among Research Programs (including terminating or postponing Research Programs); (v) discuss and approve any research to be performed by or in collaboration
with a Third Party that is primarily in the commercial antibody discovery business (as described in Section 2.8(c)), if approved by Adimab in its sole discretion; (vi) recommend to Arsanis additional research activities not described in a
Research Plan that Arsanis may, in its sole discretion, authorize Adimab to perform in the event that there is additional capacity in the Adimab FTE commitment described in Section 2.4 that is not being utilized; and (vii) perform such
other activities as the Parties agree in writing shall be the responsibility of the Research Committee. 

  
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 (d) Decision-Making. Day-to-day Research Program management and implementation shall be
the responsibility of the Parties’ respective technical teams as regards each Party’s Research Program responsibilities. The Research Committee shall have the limited authority to (i) amend each Research Plan in a manner not
substantially affecting resources required to perform such Research Plan or Success Criteria or altering timing for performance in a way that consumes fewer FTEs than scheduled unless Adimab consents in writing in its sole discretion or receives no
less than [**] days notice prior to the FTE reduction (in the latter case, subject always to and without altering the minimum FTE funding requirements in Section 4.2), and (ii) prioritize among Research Programs (including terminating or
delaying Research Programs, subject always to the same notice requirements prior to reducing FTEs as set forth in subsection (i) and subject always to and without altering the minimum FTE funding requirements in Section 4.2). Except for
the limited authority set forth in the foregoing sentence, the Research Committee shall not have any decision-making authority and the Research Committee shall have no power to amend or waive compliance with this Agreement or any Research Plan.
Decisions within the purview of the Research Committee shall be made by the Research Committee by consensus, with the representatives of each Party collectively having one vote on behalf of such Party. For each meeting of the Research Committee, at
least one (1) representative of each Party shall constitute a quorum. If the Research Committee is unable to reach a consensus with respect to a dispute within its purview (to avoid doubt, general contractual disputes and disputes as to any
decisions reserved to a Party shall not be deemed to be within the Research Committee’s purview), then the dispute resolution provisions of Section 10.2(a) shall apply; provided, however, that
(x) disputes regarding new research plans shall be resolved as set forth in Sections 2.2(e) and (1); (y) [**] shall have final decision-making authority regarding the prioritization of Research Programs (including terminating or postponing
Research Programs (subject to the notice and FTE funding qualifications described in clauses (i) and (ii) above in this paragraph); and (z) other than a dispute as to whether each Party has acted in good faith and in accordance with
this Agreement in its participation in the Research Committee, disputes of the Research Committee not resolved by the Senior Executives Discussions under Section 10.2(a) shall not be justiciable and (absent such a failure to act in good faith
and in accordance with this Agreement) shall not be litigated, and the disputed Research Committee decision not falling within (x) or (y) and not resolved under (z) shall simply not be taken. 

2.2 Addition of New Targets and Research Plans/Programs. 

(a) One Target/Program at Signing But Likelihood of More. The Parties wish to engage in the Collaboration, consisting of multiple
Research Programs. The complete details have been agreed as to only one Research Plan and Research Program as of signing, and only the Target for this first Research Program has been determined. However, it is anticipated that additional Targets
will be added by Arsanis to the Collaboration, consistent with the Research Overview and the procedures provided in this Section. For clarity, Arsanis may select additional Targets that are not listed in the Research Overview. 

  
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 (b) Selection/Notice by Arsanis. During the Target Nomination Period, Arsanis shall have
the right to select and designate new biological targets that it wishes to add to the Collaboration as Targets, by written notice to Adimab. Such written notice may be (but is not required to be) included in one of Arsanis’ regular reports
under Section 2.5(b) or in a written request for a Research Committee meeting. Adimab has no right to reject proposed Targets. 

(c) Questionnaire and Drafting Process. Promptly after Arsanis’ notice, Arsanis shall fill out and send to Adimab the Research
Program Questionnaire (the form of which is attached as Exhibit D), as well as a draft research plan (or, if the notice does not include a draft research plan, then Adimab shall provide the first draft of the research plan based on the input from
the Research Program Questionnaire). Promptly after Adimab receives the completed Research Program Questionnaire and draft research plan from Arsanis (within [**] days), Adimab shall review the Research Program Questionnaire and draft research plan
and shall provide Arsanis with any comments or questions, which will form the basis for a Research Committee meeting. If the Research Committee approves the general research plan concept, the Research Committee shall designate a working group
consisting of the technical teams of both Parties that shall finalize the Research Plan within a period of no longer than [**] weeks. The Parties shall work together collaboratively (through the Research Committee and otherwise) to revise and reach
consensus on the plan. 
 (d) Required Content in Each Proposed Research Plan. Each proposed research plan shall comply with
all of the following: 
 (i) The plan shall clearly identify the Target for which Arsanis provided its notice, in a manner
consistent with the definition of Target. 
 (ii) The plan shall clearly identify Success Criteria for the applicable Target.
If applicable, it shall additionally distinguish the criteria that serve contractually as requirements to meet the Success Criteria for purposes of this Agreement, from other criteria (if any) that are desired characteristics but are not required to
be met in order for the Success Criteria to be achieved in the applicable Research Program for purposes of this Agreement (i.e., required versus preferred characteristics). 

(iii) The plan shall describe the Arsanis Materials to be provided. 

(iv) The plan shall describe the Adimab deliverables in reasonable detail. 

(v) The plan shall describe a timeline for (w) delivery of the Arsanis Materials to Adimab, (x) commencement of
Adimab’s work under the plan, (y) delivery by Adimab of Adimab’s deliverables under the plan, and (z) if applicable, any “optional” research activities of Adimab under the plan, described below. 

(vi) The plan shall describe any research to be performed by or in collaboration with a Third Party that is approved as described in
Section 2.8(c). 

  
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 The plan may also include additional research activities that Arsanis may, in its sole
discretion, authorize Adimab to perform in the event that there is additional capacity in the Adimab FTE commitment described in Section 2.4 that is not being utilized. Such additional research activities shall be identified as
“optional” in the Research Plan, and shall only be performed by Adimab if so authorized by Arsanis in writing. For example, if a Research Plan stage is delayed because required Arsanis Materials are not available, Arsanis may authorize
Adimab to undertake some or all of the “optional” research activities described in one or more Research Plans. 
 (e) Process
Timeline and Approval Process. The process at the Research Committee level is intended to take about [**] days. Once consensus has been reached at the Research Committee level, the proposed research plan, along with a written estimate of the
FTEs required to perform Adimab’s responsibilities under each stage of the plan, shall be sent by the Research Committee for formal approval within each Party. Each Party shall respond in writing with its approval of the plan, or with any
concerns, within [**] days. Neither Party shall unreasonably withhold, delay or condition its approval to a proposed plan that is consistent with the standards above (at either the Research Committee consensus or the approval-by-the-Parties stage).
If a Party does not approve the proposed final plan, it shall provide a reason in writing and the Research Committee shall seek in good faith to find a solution, revise the plan, and resubmit for formal approval within [**] days. The plan shall
become a Research Plan under this Agreement, and if applicable, the target that it identifies shall become a Target under this Agreement, when an officer for each Party signs an approval letter approving the final plan. 

(i) Escalation in Case of Failure to Reach Consensus. If the Research Committee is unable to reach consensus on a new research plan
(either initially or after an initial plan is sent for approval but rejected by either Party), then either Party may refer the matter for further discussions by an officer or director of each Party, who is not an officer or director of and does not
have (or represent a fund that has) an equity or debt interest in the other Party, directly or indirectly. Each Party shall be entitled to select its representative and shall make such representative reasonably available for discussions and seek in
good faith to resolve the dispute over a period not longer than [**] days. In the absence of consensus, the proposed plan shall not be a Research Plan under this Agreement, but a Party shall be entitled to proceed to further escalation and dispute
resolution under Section 10.2(a) regarding the issue of whether the other Party has unreasonably withheld, delayed or conditioned its approval of the proposed research plan as a Research Plan. 

2.3 Research Program Performance. Each Party shall use its reasonable efforts to carry out the Research Program activities assigned to
such Party in each Research Plan, on the applicable timeline set forth in such Research Plan. Adimab shall deliver to Arsanis the Program Antibodies and all other deliverables described in each Research Plan in accordance with the timetable set
forth therein, but no later than the end of the applicable Research Term, unless an Arsanis re-prioritization of Research Programs results in a different timeline. Adimab’s performance obligations under each Research Plan shall be contingent
upon Arsanis providing the Arsanis Materials set forth in such Research Plan and the FTE funding as provided in this Agreement, and shall expire at the end of the Research Term. Arsanis’ performance obligations relating to testing of Program
Antibodies under a Research Plan are contingent upon Adimab providing the Program Antibodies as detailed in the Research Plan that collectively meet the applicable Success Criteria. 

  
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 2.4 Collaboration FTE Commitments. 

(a) FTE Commitment. Throughout the Target Nomination Period Adimab will make available to dedicate to the Collaboration a minimum of
one (1) campaign team consisting of [**] FTEs (to avoid doubt, individual scientific personnel may rotate on and off the campaign team and any given FTE may consist of the time of more than one person (for non-limiting example, two half-time
people)). During the Target Nomination Period Adimab will devote such FTEs to performing Research Programs to the extent there are Research Programs (and applicable Arsanis Materials received to enable Adimab performance). During the Target
Nomination Period more than [**] FTEs may be performing activities under the Research Programs at any given time, however, the total number of FTEs performing such activities shall not exceed [**] FTEs on average in any [**] month period without the
prior written consent of both Parties. No later than [**] months prior to the expiration of the Target Nomination Period, Arsanis shall notify Adimab in writing of those Research Programs that Arsanis elects (in its sole discretion) to pursue during
the Tail Period (or any portion thereof) and Adimab will provide Arsanis with a schedule of the FTE usage required by Adimab to complete such Research Programs. During the Tail Period Adimab will devote the number of FTEs required to complete such
Research Programs, however, Adimab’s aggregate FTE commitment during the Tail Period shall not exceed [**] FTEs per year over such period taken as a whole unless agreed by the Parties in writing. Adimab shall not be required during the Target
Nomination Period or during the Tail Period to devote any FTEs to performing Research Programs, other than FTEs funded by Arsanis under Section 4.2. 

(b) Funding. Arsanis is responsible to fund the FTEs devoted by Adimab to the Collaboration as set forth in Section 4.2. 

(c) Exclusive Use of Campaign Manager. During the applicable Research Term, and for a period of [**] thereafter, the person whom Adimab
has designated as the “Campaign Manager” for a given Research Program shall not perform, or supervise the performance of, research relating to the corresponding Target using Adimab Platform/Core Technology for Adimab or its Affiliates
(whether for their own account or on behalf of any Third Party). It is understood and agreed that if such a person is no longer in Adimab’s or its Affiliate’s employ, then such person’s activities for another employer are beyond the
scope of (and are not Adimab’s responsibility to prevent under) the foregoing sentence. 
 2.5 Records and Reports.

 (a) Records. Each Party shall maintain scientific records, in sufficient detail and in good scientific manner appropriate for
patent and regulatory purposes, which shall fully and properly reflect all work done and results achieved in the performance of the Collaboration. All such records and the information disclosed therein shall be maintained in confidence in accordance
with Article 6 to the extent reflecting Confidential Information of the other Party. Adimab shall not be required to disclose [**] to Arsanis, even if reflected in such records. 

(b) Reports By Adimab. At the junctures specified in each Research Plan, Adimab shall provide written reports to Arsanis of the Program
Antibodies Adimab has identified under that Research Plan, and any information with respect to them that such Research Plan provides for Adimab to disclose. Adimab shall not be required to disclose any [**] to Arsanis. 

  
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 (c) Reports By Arsanis. During the Research Term at the junctures set forth in the
Research Plan, and then [**] throughout the term of the applicable Option and for so long as Arsanis or any of its Affiliates, successors, licensees or sublicensees continue to generate or test any Program-Benefited Antibodies, Arsanis shall provide
written reports to Adimab. Arsanis’ reports shall provide any Program Know-How developed by Arsanis in the applicable Research Program that Arsanis is required to provide under the Research Plan, and shall disclose all Program-Benefited
Antibodies since the date of the last report. Such reports and their contents are Confidential Information of Arsanis (except to the extent that Arsanis includes any Adimab Confidential Information in the reports). 

2.6 Use of Adimab Materials. Arsanis shall not use Adimab Materials in any way outside of the Research Program or other than pursuant
to the licenses granted under this Agreement while such licenses are in effect. Among other things, this means that, except under the applicable Research Program as outlined in the applicable Research Plan or pursuant to such licenses, Arsanis shall
not: (a) provide Adimab Materials to any Third Party (except permitted Third Party contractors and collaborators as described in Section 2.8), (b) sequence or modify the Adimab Materials, or (c) use sequence information
regarding, or quantities of, Program Antibodies or Adimab Materials for any purpose other than to research, develop and commercialize Program-Benefited Antibodies pursuant to Section 3.5. 

Adimab retains title to the Adimab Materials, including all quantities of Program Antibodies that it provides under the Collaboration. Unless
Arsanis exercises an Option with respect to such Program Antibodies, such quantities of Program Antibodies are for use solely in assessing whether to exercise the Options. Such quantities shall not be [**]; provided, however, that
Arsanis may use such quantities to compare the performance of Program Antibodies in various assays against other Program Antibodies, and against benchmark research antibodies, benchmark commercial antibodies or any other benchmark agent, including
small molecules and biological agents, all of which prior to the comparison to Program Antibodies have previously been identified as having activity against, binding to, agonizing, antagonizing or inhibiting the applicable Target (provided,
that negative controls already identified as such are permitted to be used). Unless Arsanis exercises the applicable Option, on expiry of the applicable Option Term, or earlier termination of this Agreement, Arsanis shall return to Adimab or destroy
the remaining quantities of Program Antibodies provided by Adimab for each Target, if Adimab requests in writing. Without limiting the generality of the foregoing, Arsanis shall not provide Program Antibodies to Third Parties who are in the
commercial antibody discovery business, except as provided in Section 2.8(b) or the last sentence of Section 2.8(c). 
 2.7 Use of
Arsanis Materials. Adimab shall not use Arsanis Materials in any way other than to perform Adimab’s obligations under a Research Program or pursuant to the license granted under this Agreement while such license is in effect. Adimab shall
not transfer the Arsanis Materials to any Third Parties or outside of Adimab. 

  
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 Arsanis retains title to the Arsanis Materials, including all quantities of antigens that it
provides under the Collaboration. Upon expiration of the Research Term for each Research Program, or earlier termination of this Agreement, Adimab shall return to Arsanis or, if requested by Arsanis in writing, destroy the remaining quantities of
Arsanis Materials provided for use in such Research Program. 
 2.8 Third Party Contractors and Collaborations. 

(a) Contractors. Arsanis may utilize the services of Third Parties that are not in the commercial antibody discovery business to
perform its obligations under the Collaboration and to perform research in order to evaluate Program Antibodies in order to determine whether to exercise one or more Options under this Agreement, Arsanis’ agreement with any such Third Party
shall be consistent with the applicable terms of this Agreement (including Section 2.6), provide Adimab the same rights under this Agreement as if Arsanis had done the work itself, and include confidentiality and non-use provisions that are no
less stringent than those set forth in Article 6 of this Agreement. 
 (b) Collaborators. The Parties agree that it may be
necessary or useful for Arsanis to enter into collaborations with Third Parties that are academic or non-profit institutions and not fee-for-service contractors (as described in Section 2.8(a) above), are not primarily in the commercial
antibody discovery business, and provide Know-How and other intellectual property that are necessary or useful for Arsanis to perform its obligations under the Collaboration and to evaluate Program Antibodies in order to determine whether to
exercise one or more Options under this Agreement. Arsanis’ agreement with any such Third Party shall contain (i) restrictions on the use of Adimab Materials consistent with Section 2.6 (including the prohibition on using Program
Antibodies in screening), (ii) confidentiality and non-use provisions that are no less stringent than those set forth in Article 6 of this Agreement, and (iii) provisions that ensure that any and all data and results arising out of the
Third Party collaboration may be provided to Adimab as and to the extent contemplated under this Agreement. Arsanis shall use commercially reasonable efforts to ensure that it obtains the right to assign, license or sublicense to Adimab any
intellectual property rights arising out of the Third Party collaboration that constitutes an Adimab Platform/Core Technology Improvement, or, if it believes it will not be practicable to obtain such right to assign, license or sublicense to Adimab,
then Arsanis shall not disclose or transfer to the applicable Third Party (x) any Adimab Confidential Information other than Program Antibody sequences or (y) any Adimab Materials other than Program Antibody samples. 

(c) Commercial Antibody Discovery Businesses. In the event that a research arrangement is contemplated by Arsanis, that would be with a
Third Party that is in the commercial antibody discovery business but not a collaborator as described in Section 2.8(b) above, in connection with the Collaboration or to evaluate Program Antibodies in order to determine whether to exercise one
or more Options under this Agreement, the Research Committee shall discuss the matter. If the Research Committee agrees to recommend to Adimab approval of such research arrangement, then Arsanis shall request Adimab’s approval of such research
arrangement in writing and Adimab shall either approve or veto such research arrangement within [**] days after such written request. If Adimab in its sole discretion approves of such research arrangement in writing, with or without specific terms
and restrictions as a condition of Adimab’s approval, and Arsanis once notified in writing of any such condition continues to wish in its sole discretion to proceed with the research arrangement, then the 

  
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Research Plan shall be amended by mutual agreement of the Parties to include such research arrangement (together with any such conditions). However, this Section 2.8(c) shall not apply
to prohibit Arsanis from providing Program Antibody samples to contract research organizations for use solely in testing that does not involve using the Program Antibodies in screening for the activity or interaction of other antibodies via or with
the applicable Target, even if in unrelated work for Third Parties the contract research organization may perform antibody discovery activities; provided that the arrangements with the contract research organization are otherwise fully in
compliance with Section 2.8(a). 
 2.9 Non-Exploitation of Program Antibodies by Adimab (Unless Independently
Discovered) At All Times. Unless independently rediscovered in full compliance with Section 2.4(c) and without the use of (a) Arsanis Materials, (b) Confidential Information of Arsanis (subject to Section 6.2(e)
regarding independent development of such information), or (c) Program Inventions or Program Know-How (other than Adimab Platform/Core Technology Improvements and subject to Section 6.2(e)), Adimab and its Affiliates shall not
(i) provide the Program Antibodies or their sequences to any Third Party at any time, or (ii) use the Program Antibodies or their sequences to research, develop, manufacture or commercialize biologic or drug products in the Field for
Adimab, its Affiliates or for any Third Parties. This clause is in no way intended to limit Adimab’s ability to transfer (including licensing) its Adimab Platform/Core Technology (including antibody libraries) to other entities or for those
entities to use the Adimab Platform Technology (including antibody libraries). Adimab is not under any circumstances required by this Agreement to remove or screen out any antibodies (or coding sequences) from its antibody (or coding sequence)
libraries. Adimab may independently regenerate such coding sequences without use or reference to the Program Inventions and/or Program Know-How, other than any Adimab Platform/Core Technology Improvements (which nothing in this Agreement shall be
read to restrict Adimab from using). In the case of independent rediscovery as provided in the first sentence of this Section, Adimab shall be unrestricted in its use of and ability to provide the applicable independently rediscovered and/or
independently regenerated antibodies to others. 
 ARTICLE 3 

LICENSES; OPTION; DEVELOPMENT & COMMERCIALIZATION 

3.1 Mutual Research Program Licenses. 

(a) To Arsanis. Adimab and its Affiliates hereby grant Arsanis a non-exclusive license under the Adimab Platform/Background Patents,
Adimab Program Patents, Adimab Program Antibody Know-How and Program Know-How made by Adimab, for Arsanis to perform Arsanis’ responsibilities as provided for in the Research Plan as part of the Research Program during the Research Term, and
for Arsanis to perform research (but excluding human clinical trials) of the Program Antibodies to each Target during the Option Term for that Target in order to evaluate whether to exercise the Option with respect to that Target and one (1) or
more of such Program Antibodies directed to that Target. The foregoing license excludes the right to discover antibodies and excludes the right to use Program Antibodies to screen for other antibodies’ activity vis-à-vis the Target (such
exclusion including the right to use the Program Antibodies as a control to test, screen for or design other antibodies), except that Arsanis may  

  
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use such quantities to compare the performance of Program Antibodies in various assays against other Program Antibodies, and against benchmark research antibodies, benchmark commercial
antibodies or any other benchmark agent, including small molecules and biological agents, all of which prior to the comparison to Program Antibodies have previously been identified as having activity against, binding to, agonizing, antagonizing or
inhibiting the applicable Target (provided that negative controls already identified as such are permitted to be used). The foregoing license is subject to Arsanis’ compliance with the restrictions on use of Adimab
Materials set forth in Section 2.6. 
 (b) To Adimab. Arsanis and its Affiliates hereby grant to Adimab a non-exclusive
license under all Patents and Know-How Controlled by Arsanis (or its Affiliate) and relating in any way to the Target for each Research Program (including any that so relate by claiming antibodies directed to that Target or a mechanism of action via
that Target) or any Arsanis Materials, for Adimab to perform Adimab’s responsibilities as provided for in the applicable Research Plan as part of the applicable Research Program during the applicable Research Term. The foregoing license is
subject to Adimab’s compliance with the restrictions on use of Arsanis Materials set forth in Section 2.7. 
 3.2 Arsanis
Option. Adimab hereby grants Arsanis the exclusive option to obtain the licenses of Section 3.3 and assignment of corresponding Antibody Sequence Coverage for the corresponding Licensed Antibodies, exercisable in relation to each Target by
Arsanis in its sole discretion upon written notice to Adimab on or before the expiry of the Option Term for such Target. Arsanis shall, in its written notice to exercise the Option, specify up to [**] Program Antibodies as the “Licensed
Antibodies” for that Target. Once the Licensed Antibodies have been identified through such Option Exercise notice, the assignment to Arsanis of the Antibody Sequence Coverage on such Licensed Antibodies shall become effective. 

3.3 Development/Commercialization License. Adimab and its Affiliates hereby grant to Arsanis for each Target, effective on Option
exercise for that Target, a worldwide, royalty-bearing, sublicenseable (solely as provided in this Section) license under the relevant Adimab Platform/Background Patents, Licensed Program Antibody Patents, Adimab Program Antibody Know-How and
Program Know-How made by Adimab, in the Field, to research, develop, make, have made, use, sell, offer to sell, import and export Licensed Antibodies to such Target and Products based on Licensed Antibodies to such Target during the term of this
Agreement. Such license shall be exclusive (even as to Adimab, except as regards the retained library rights of Section 5.2(c)) under the Licensed Program Antibody Patents) and subject to Section 6.2(e) shall be exclusive even as to Adimab
under the Adimab Program Antibody Know-How. Such license shall be non-exclusive under the Adimab Platform/Background Patents. Such license shall be sublicensable through one (1) or more tiers of sublicensees without the need to obtain consent;
provided, that the sublicense agreement (a) is consistent with and subject to this Agreement, contains provisions that enable Arsanis to comply with its reporting obligations under this Agreement (e.g., reporting and audit provisions),
(b) requires the sublicensee(s) at each tier to indemnify Adimab on the same basis as provided for in Article 8 (and the sublicense shall provide that Adimab is a third-party beneficiary of such indemnification obligation) and (c) shall
provide that if Arsanis makes the Royalty Election under this Agreement with respect to the sublicense, then (i) such sublicense shall contain royalty payment obligations of the sublicensee that are sufficient to cover the royalty payment
obligations pursuant to Section 

  
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4.5 to Adimab of [**] percent ([**]%) of Net Sales made within the scope of such sublicense and (ii) Adimab shall be an intended third-party beneficiary of such royalty payment obligations
of the sublicensee under such sublicense (without imposing any greater obligation on the sublicensee than imposed on Arsanis under this Agreement) and of the indemnification obligation required under clause (b). The requirements of the foregoing
sentence as to sublicensees shall also apply to all Program Transaction counterparties. 
 3.4 Diligent Development and
Commercialization. 
 (a) Diligent Efforts. “Commercially Reasonable Efforts” means, with respect to a
Product, the level of efforts required to carry out a task in a diligent and sustained manner without undue interruption, pause or delay; which level is at least commensurate with the level of efforts that a similarly situated biopharmaceutical
company would devote to a product of similar market potential at a similar stage in development or product life, taking into account the following factors: issues of safety and efficacy; the competitiveness of alternative products; the patent or
other proprietary position of the Product; pricing and reimbursement; product profile, difficulty in and costs of developing or manufacturing the Product, competitiveness of the Product and alternative Third Party products in the marketplace; the
regulatory structure involved in developing and commercializing the product; the potential profitability of the Product marketed or to be marketed; and all other relevant scientific, technical and commercial factors. Commercially Reasonable Efforts
shall be determined on a country-by-country basis, and it is anticipated that the level of effort will change over time reflecting changes in the status of the Product and the market involved. Arsanis shall, for each Target for which the Option is
exercised, devote Commercially Reasonable Efforts to preclinically and clinically develop, seek Marketing Authorization for, and launch and actively commercialize at least one (1) Product containing a Licensed Antibody to such Target, for the
Major Markets. 
 (b) Reports. [**], Arsanis will provide Adimab with a written report summarizing Product progress in
development and commercialization, and Arsanis’ and its Affiliates’ significant activities in that regard, on a Target-by-Target basis. If requested by Adimab, Arsanis shall meet with Adimab to discuss such report at least [**]. Arsanis
shall make the following personnel available for such meetings: the [**] (or equivalent) for Product development, and another person at [**] or above. These meetings are not required of Third Party sublicensees or Program Transaction counterparties
of Arsanis or its Affiliates, or of Arsanis with respect to any Target for which all rights of Arsanis under this Agreement with respect to Licensed Antibodies to such Target have been out-licensed or transferred to Third Parties. 

3.5 Commitments Regarding Program-Benefited Antibodies. 

(a) Program-Benefited Antibodies. The Parties intend that if Arsanis or its Affiliates pursue any antibody that benefits from the
antibody discovery work performed by Adimab under this Agreement, they shall do so under this Agreement paying fees to Adimab as provided in Article 4 (and complying with all other provisions of Article 4, including notice requirements, in the same
way as such provisions apply to Program Antibodies). This Agreement gives Arsanis and its Affiliates the right to modify the Licensed Antibodies, by including modified versions of them and derivatives of them in the definition of “Product”

  
 22 

 
provided above. Arsanis and its Affiliates shall also be entitled to use sequence-related information obtained under this Agreement to research, develop and commercialize antibody products in the
Field that are not Products. However, the Parties intend that Arsanis and its Affiliates shall not ever develop or commercialize an antibody product using, or that is based on, (a) a Program Antibody, (b) a derivative or modified version
(as described above in this Section 3.5 or in the definition of Product) of a Program Antibody, or (c) sequence information as to any Program Antibody or the nucleic acid coding for it (each of the foregoing in this sentence, a
“Program-Benefited Antibody”), without exercising the applicable Option and paying Adimab fees pursuant to Article 4 with respect to such Program-Benefited Antibody and/or product containing such Program-Benefited Antibody as if
such Program-Benefited Antibody were deemed a Licensed Antibody and such Program-Benefited Antibody product were deemed a Product under this Agreement. A Program-Benefited Antibody shall not include any antibody that is independently discovered or
developed without the use of (i) Adimab Materials, (ii) Confidential Information of Adimab (subject to Section 6.2(e) regarding independent development of such information), (iii) sequence information as to Program Antibodies
unless published by Adimab or its Affiliate (and excluding publications of patents prosecuted under this Agreement by Arsanis, whether or not consented to by Adimab) or any Third Party that did not obtain such sequence information directly or
indirectly from Arsanis or its Affiliates (with indirect receipt including the situation in which a Third Party obtains the sequence from a publication of a patent application filed by or scientific article of Arsanis or its Affiliate),
(iv) Adimab Program Antibody Inventions, (v) Program Know-How made or developed by Adimab (subject to Section 6.2(e)), or (vi) Joint Program Antibody Inventions (i.e., if any of (i)-(vi) is used, the antibody is a
Program-Benefited Antibody). For clarity, an antibody product will not be deemed a Program-Benefited Antibody solely through the application or use of a Broad Non-CDR Antibody Invention in the discovery, research, development, manufacture or
commercialization of such antibody product. Arsanis shall comply with its regular reporting obligations as to Program-Benefited Antibodies as in Section 2.5(c). An antibody product will not be deemed a Program-Benefited Antibody solely because
covered by an Epitope Patent; provided that Arsanis makes the payments to Adimab provided for in this Agreement in relation to transactions involving Epitope Patents. 

Notwithstanding the definition of “Program-Benefited Antibody” stated in the foregoing paragraph, the following shall not be deemed
Program-Benefited Antibodies for any purpose under this Agreement: (x) antibodies first discovered after the date of an Arsanis Trade Sale for which the Revenue Election was made if there were substantial Undesignated Rights at the time of the
Arsanis Trade Sale; and (y) antibodies first discovered more than [**] years after the date of an Arsanis Trade Sale. 
 (b)
Covenant Not to Sue. Except as provided in the last sentence of this Section, so long as Arsanis and its Affiliates are in compliance with Section 3.5(a) with respect to a Program-Benefited Antibody, Adimab shall not, directly or
indirectly, assert any claim against Arsanis or its Affiliates, successors in interest, acquirers (whether of Arsanis or of all or substantially all of the assets of Arsanis relating to the subject matter of this Agreement), licensees, or
sublicensees, distributors or end users, with respect to the research, development, manufacture, sale, offering for sale, import or export of any product containing such Program-Benefited Antibody, for infringement of any Licensed Program Antibody
Patents and/or Adimab Platform/Background Patents or misappropriation of Adimab Program Know-How with respect 

  
 23 

 
to Licensed Antibody(ies). The foregoing covenant shall be binding on all of Adimab’s Affiliates and successors in interest under this Agreement, and any exclusive licensees, exclusive
sublicensees, and assignees of any Licensed Program Antibody Patents, Adimab Platform/Background Patents and Adimab Program Know-How regarding Licensed Antibody(ies), and Adimab shall as a condition of assigning this Agreement, or providing the
applicable exclusive license, exclusive sublicense or assignment, obtain a contractual commitment from the applicable entity receiving rights to comply with such covenant. Such covenant does not apply to any Patent other than a Licensed Program
Antibody Patent or Adimab Platform/Background Patent. For purposes of this Section 3.5(b), Adimab Platform/Background Patents and Licensed Program Antibody Patents shall be interpreted as if the Program-Benefited Antibodies were Licensed
Antibodies. The covenant of this Section 3.5(b) shall not apply to activities after a termination of this Agreement in its entirety or surrounding the Target to which the Program-Benefited Antibody relates, in each case for Arsanis uncured
material breach. This Section 3.5(b) shall not be read to allow, or prevent a suit by Adimab with respect to, Arsanis’s practice of Adimab Platform/Core Technology for antibody discovery purposes. 

ARTICLE 4 
 FINANCIAL
TERMS. 
 4.1 Technology Access Fee. Arsanis shall pay Adimab a technology access fee equal to [**] dollars ($[**]), within [**]
Business Days after the Signing Date. 
 4.2 Research Funding. 

(a) Funding Amounts. Arsanis shall pay Adimab for the FTEs actually performing scientific work in each Research Program under the
Collaboration during the Collaboration Term at the FTE Rate; provided, however, that Arsanis will not be responsible to fund any Adimab FTEs in excess of an average of [**] per month during any [**]-month period of the
Collaboration Term without Arsanis’ prior written consent. Adimab acknowledges and agrees that the FTE Rate reflects Adimab’s fully-loaded costs and expenses in performing its Research Program obligations under the Collaboration, and that
Adimab is solely responsible for its internal and external costs and expenses in performing its obligations thereunder (provided that Adimab shall not be required to devote FTEs to the Research Programs which FTEs are not funded
by Arsanis under this Section). During all accounting periods of the Target Nomination Period, Arsanis is required to pay Adimab for a minimum of [**] FTEs in such accounting period, even if Arsanis does not provide Targets such that there are
Target Research Programs for such FTEs to work on or authorize Adimab to perform any “optional” research activities under a Research Plan as described in the last paragraph of Section 2.2(d). 

(b) Invoicing and Payments. Payments under this Section shall be due quarterly in advance based on scheduled FTE usage, subject to
true-up each quarter at the end of the quarter. If Arsanis has paid for more FTEs than are actually used in any calendar quarter, then any such overpayment shall be promptly refunded to Arsanis or deducted from future calendar quarter advance
payments under this Section, in Arsanis’ sole discretion, At least [**] days prior to the Start Date, and at least [**] days prior to the commencement of each calendar 

  
 24 

 
quarter during the Collaboration Term thereafter, Adimab shall deliver to Arsanis a detailed invoice stating the number of FTEs that are scheduled to perform activities under the Collaboration
during such calendar quarter. The first advance payment under this Section 4.2 shall be on or prior to the Start Date (or [**] days after receipt of the applicable invoice, if later) and shall be calculated on the scheduled FTE usage for the
period commencing on the Start Date and ending on September 30, 2011. Thereafter, each quarterly advance payment will be due on or prior to the first Business Day of each calendar quarter during the Collaboration Term (or [**] days after
receipt of the applicable invoice, if later) and shall be calculated on the scheduled FTE usage for the upcoming calendar quarter. Within [**] days after the end of each calendar quarter during the Collaboration Term Adimab shall deliver to Arsanis
a detailed invoice stating the number of FTEs that actually performed activities under the Collaboration during the prior calendar quarter, the amount of any advance payments made by Arsanis (or credits due to Arsanis) in respect of such activities,
and any true-up amount due. All payments shall be due within [**] days of Arsanis’ receipt of the invoice. 
 4.3 Election Between
Program Transaction Revenue Payments and Royalty Payments. 
 (a) General Case. Within [**] days after a Program
Transaction is entered into, Arsanis shall inform Adimab in writing whether Arsanis elects to pay a share of Program Transaction Revenue with respect to such Program Transaction as in Section 4.4, or instead elects to pay a Net Sales royalty on
Products sold pursuant to rights included in such Program Transaction as in Section 4.5. Arsanis is entitled to make such election on a Program Transaction-by-Program Transaction basis. If Arsanis elects the former, then it has made the
“Revenue Election” with respect to the particular Program Transaction and shall simultaneously with such notice disclose to Adimab a copy of all documents governing such Program Transaction, but shall be entitled to redact from the
copy shared with Adimab reasonable amounts of information not relevant to the determination of Program Transaction Revenue or any allocation thereof pursuant to Section 4.3(c), (d) or (e) hereunder or confirmation that the agreements
comply with this Agreement (e.g., the requirement that sublicensees provide appropriate indemnification of Adimab). If Arsanis elects the latter, then it has made the “Royalty Election” with respect to the particular Program
Transaction, and shall disclose simultaneously with such notice a copy of all documents governing such Program Transaction, but shall in this case be entitled to redact from the copy shared with Adimab reasonable amounts of information not relevant
to the calculation of royalties hereunder or confirmation that the agreements comply with this Agreement (e.g., the requirement that sublicensees provide appropriate indemnification of Adimab). All Program Transaction documents provided by Arsanis
to Adimab and the terms and information contained therein shall be Confidential Information of Arsanis subject to the provisions of Article 6. 

If Arsanis fails timely to elect either the Revenue Election or the Royalty Election, then the Royalty Election shall automatically be deemed
made for that Program Transaction. Once Arsanis makes either the Revenue Election or the Royalty Election with respect to a particular Program Transaction (or the Royalty Election is deemed made as provided for in the immediately preceding
sentence), this election is irrevocable as to the particular Program Transaction. If no election under this Section has been made as of the date of First Commercial Sale of any given Product in any given country, then the Royalty Election shall
automatically be 

  
 25 

 
made as to such Product in such country (and the Revenue Election shall not be an option as to such Product in such country). Moreover, at any time that is prior to the closing of an Arsanis
Trade Sale, upon written notice to Adimab, Arsanis may make an irrevocable Royalty Election with respect to a Product in any jurisdiction, indication and/or field of use as to which no Revenue Election has previously been made; provided,
however, that Arsanis’ right to do so prior to an Adimab Change of Control shall not be read to imply any right for Arsanis to require revenue allocation or baseball arbitration in connection with an Arsanis Trade Sale occurring prior to
an Adimab Change of Control, even if Arsanis makes Royalty Elections under this sentence prior to such time. 
 (b) Arsanis Trade
Sale. Unless the Parties agree otherwise in writing prior to the closing of an Arsanis Trade Sale, then for all Undesignated Rights transferred pursuant to such Arsanis Trade Sale, the “Royalty Election” shall automatically be made.

 At any time prior to an Arsanis Trade Sale Arsanis may notify Adimab in writing of its desire to elect to pay Adimab [**] percent
([**]%) of the proceeds of an Arsanis Trade Sale that are agreed by the Parties to be reasonably attributable to Undesignated Rights and/or Epitope Patents, in lieu of the Royalty Election automatically applying with respect to such Undesignated
Rights. Adimab and Arsanis shall each be reasonably available to negotiate in good faith such allocation of Arsanis Trade Sale proceeds within [**] days after the date of such Arsanis notice. 

If despite good faith efforts the Parties are unable to agree upon such allocation within such [**] day period, and: 

(i) Adimab has not undergone an Adimab Change of Control, then Arsanis shall either (1) accept the Royalty
Election as applied to all Undesignated Rights at the time of the Arsanis Trade Sale, or (2) choose instead to deem the Arsanis Trade Sale a Program Transaction and pay to Adimab [**] percent ([**]%) of all associated Program Transaction
Revenue; Arsanis shall notify Adimab in writing within [**] days after the Arsanis Trade Sale which alternative Arsanis has elected; or  

(ii) Adimab has undergone an Adimab Change of Control, then Arsanis may request that a Third Party determine an
amount to be allocated to Program Transaction Revenue for the particular Arsanis Trade Sale, by baseball arbitration pursuant to Section 10.2(b). Any allocation determined by such baseball arbitration shall only be valid as to an Arsanis Trade
Sale transaction on the terms disclosed in writing by Arsanis to Adimab and the Arbitrator pursuant to such baseball arbitration; if an Arsanis Trade Sale ultimately occurs on different terms, then the allocation must either be agreed by the Parties
or re-arbitrated by baseball arbitration in accordance with Section 10.2(b). 
 The amount allocated by written agreement of
the Parties or by such arbitration after an Adimab Change of Control shall be the “Program Trade Sale Proceeds.” If the Parties did not reach written agreement, and Adimab has not at that time undergone an Adimab Change of Control
prior to the Arsanis Trade Sale, then Program Trade Sale Proceeds shall be equal to all Program Transaction Revenue associated with the Arsanis Trade Sale, treating the Arsanis Trade Sale as a Program Transaction. 

  
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 After an Arsanis Trade Sale, Revenue Elections for pre-existing (prior to the Arsanis Trade Sale)
Program Transactions with a Third Party will continue to apply only for so long as such rights remain with the Third Party (and if such rights ultimately revert to Arsanis or its successor then they shall be subject to the Royalty Election) and
there shall be no offset of payments already made to Adimab in respect of such pre-existing Program Transaction against royalties due to Arsanis under such Royalty Election, Furthermore, if the counterparty to the Arsanis Trade Sale was (or its
Affiliate was) a counterparty to a Program Transaction for which a Revenue Election or Royalty Election was previously made, and such Program Transaction is terminated or amended in connection with the Arsanis Trade Sale prior to an Adimab Change of
Control, then Arsanis shall be required to make the same election for the Arsanis Trade Sale as was made for such Program Transaction unless Adimab agrees otherwise in writing in its sole discretion. To avoid doubt, the foregoing sentence does not
apply to similar situations occurring after an Adimab Change of Control. 
 For clarity, if the proceeds of an Arsanis Trade Sale are
subject to increase by contingent payments related to future events and/or release of escrowed amounts, such increased amounts shall be included as proceeds of an Arsanis Trade Sale only as and when such payments are received by Arsanis, its
Affiliate(s), or shareholder(s) or former shar eh older (s) of any of them (but in this last case only if they are receiving payments due to their shareholding prior to the Arsanis Trade Sale). 

Once the Royalty Election applies to any rights under this Section 4.3(b), it is irrevocable. To avoid doubt, this means that if the
surviving or acquiring entity later licenses rights to Licensed Antibodies transferred pursuant to the Arsanis Trade Sale to a Third Party, the Royalty Election shall continue to apply to such Licensed Antibodies, and the surviving or acquiring
entity will not have the opportunity to elect otherwise under Section 4.3(a). 
 (c) Multi-Product Deals. (i) At any time
during the term of this Agreement Arsanis may, in its sole discretion, notify Adimab in writing that it is interested in making a Revenue Election with respect to a particular proposed Multi-Product Deal. Arsanis will promptly provide Adimab the
relevant Program Transaction documents as described in Section 4.3(a) and Adimab and Arsanis will negotiate and endeavor to agree in good faith the allocation of Program Transaction Revenue to Multi-Product Deal Program Transaction Revenue in
such Multi-Product Deal within [**] days after the date of such Arsanis notice. If despite good faith efforts the Parties are unable to agree upon such allocation within such [**] day period, and Adimab has undergone an Adimab Change of Control
prior to the Multi-Product Deal, then Arsanis may request that a Third Party determine such allocation by baseball arbitration pursuant to Section 10.2(b). If despite good faith efforts the Parties are unable to agree upon such allocation
within such [**] day period, and Adimab has not undergone an Adimab Change of Control prior to the Multi-Product Deal, then Arsanis shall not have any right to refer the matter for dispute resolution or baseball arbitration
under Section 10.2(b), and there shall be no reduction or adjustment to Program Transaction Revenue for other products in the applicable Multi-Product Deal (if Arsanis makes the Revenue Election for such Program Transaction). 

  
 27 

 (ii) For each Program Transaction that is part of a Multi-Product Deal, the Royalty Election
shall be deemed made automatically if Arsanis does not (in its discretion) within [**] days after the date of such Program Transaction notify Adimab in writing that Arsanis makes the Revenue Election with respect thereto and either (A) confirm
(accurately) its agreement to an allocation of Program Transaction Revenue to Multi-Product Deal Program Transaction Revenue with respect to such Multi-Product Deal (which shall be mere confirmation of an allocation previously negotiated in good
faith and agreed to in writing by the Parties or (if the matter initially arose after an Adimab Change of Control) determined by the arbitrator pursuant to Section 10.2(b) (in those cases where arbitration is available because Adimab has
undergone an Adimab Change of Control prior to the Multi-Product Deal), and the notice shall only be effective if merely confirmatory), or (B) if the Parties have not previously agreed on such allocation or submitted the allocation dispute to
arbitration pursuant to Section 10.2(b) below, and Adimab has previously undergone an Adimab Change of Control, then request that a Third Party determine such allocation by baseball arbitration as set forth in Section 10.2(b). If Adimab
has not undergone an Adimab Change of Control prior to the Multi-Product Deal, then Arsanis shall not have any right to refer the matter for dispute resolution or baseball arbitration under Section 10.2(b), and there shall be [**] to Program
Transaction Revenue in the applicable Multi-Product Deal based on Multi-Product Deal status (i.e., Multi-Product Deal Program Transaction Revenue for the particular Multi-Product Deal shall be equal to [**]% of the Program Transaction Revenue
associated with such Multi-Product Deal). 
 (d) Multi-Target Deals. Section 4.3(c) shall apply mutatis mutandis to
Multi-Target Deals in order to allocate Program Transaction Revenue to Multi-Target Deal Revenue. 
 (e) Program Revenue Transactions
Involving Combination Products. If the lead and/or any actively developed backup Product candidate or Product in a Program Transaction is a Combination Product, then Section 4.3(c) shall apply mutatis mutandis to allow
for proportional reduction of Program Transaction Revenue by mutual written agreement of the Parties, or, if (and only if) Adimab has undergone an Adimab Change of Control prior to the applicable Program Transaction, by baseball arbitration under
Section 10.2(b). 
 (f) Program Transactions Involving Only Epitope Patents. For Program Transactions that are only Program
Transactions because of the inclusion of Epitope Patents in the transaction (i.e., that do not otherwise include Licensed Antibodies, Program-Benefited Antibodies or intellectual property arising out of the Collaboration or with respect to the
foregoing other than Epitope Patents and Broad Non-CDR Antibody Inventions) (an “Epitope- IP-Only Transaction,” but only if both (i) not entered into contemporaneously with, and (ii) regardless of timing, not entered into
with the same counterparty as, any other transaction that itself would be a Program Transaction relating to the same Target; “same counterparty as” for the purpose of this Section 4.3(f) shall refer to the contracting entity and all
Affiliates of such contracting entity), Arsanis may pay to Adimab an amount equal to [**] Dollars ($[**]); such payment being due within [**] days after such Epitope- IP-Only Transaction (“Epitope IP Compensation”), and if Arsanis
does so, then Arsanis shall not owe any share of Program Transaction Revenue with respect to such Epitope-IP-Only Transaction, and shall not owe any Net Sales royalties with respect to Net Sales within the scope of such Epitope-IP-Only Transaction,
Notwithstanding anything express or implied in the foregoing, paying the Epitope IP Compensation shall not result in any reduction in Program Transaction Revenue payable in case of another Program Transaction relating to the same Target with the
same counterparty (including an Affiliate of the contracting entity). If Arsanis does not timely pay the Epitope IP  

  
 28 

 
Compensation for any Epitope-IP-Only Transaction, then such Epitope-IP-Only Transaction shall be treated as any other Program Transaction for purposes of this Agreement and there shall be no
reduction of any kind to Program Transaction Revenue associated therewith if Arsanis makes the Revenue Election with respect to such Program Transaction. To avoid doubt, if a Program Transaction includes Epitope Patents (including the situation in
which an Epitope Patent transaction is deemed part of a Program Transaction because entered into contemporaneously with, or regardless of timing, with the same counterparty (with counterparty having the same meaning as provided above) and relating
to the same Target as, other elements of the Program Transaction), there shall be no adjustment or reduction of Program Transaction Revenue in relation to the Epitope Patents. 

4.4 Program Transaction Revenue Payments. Arsanis shall pay to Adimab [**] percent ([**]%) of all Program Transaction Revenue in
connection with Program Transactions for which the Revenue Election is made (other than Multi-Product Deals or Multi-Target Deals); [**] percent ([**]%) of Multi-Product Deal Program Transaction Revenue for all Multi-Product Deals for which the
Revenue Election is made; and [**] percent ([**]%) of Multi-Target Deal Program Transaction Revenue for all Multi-Target Deals for which the Revenue Election is made. Each of the foregoing shall be subject to adjustment (if any) under
Section 4.3(e) in the Combination Product circumstances in which it applies. The amounts due under this Section shall be payable on an ongoing basis within [**] days after the calendar month in which Program Transaction Revenue, Multi-Target
Deal Program Transaction Revenue or Multi-Product Deal Program Transaction Revenue, as the case may be, is received. 
 4.5
Royalty Payments. If the Royalty Election applies, then: 
 (a) Royalty Rate for Products. Arsanis shall pay Adimab
royalties at the rate of [**] percent ([**]%) of Net Sales of each Product during the applicable Royalty Term, determined on a country-by-country and Product-by-Product basis in accordance with Section 4.5(b). 

(b) Royalty Term. “Royalty Term” means, on a Product-by-Product and country-by-country basis, the time from the First
Commercial Sale of such Product in such country until the twelve (12) year anniversary of the First Commercial Sale of such Product in such country. 

(c) Combination Products Adjustment. If Arsanis, its Affiliate, their successors or the Product marketer of any of them under a Program
Transaction for which the Royalty Election has been made sells a Combination Product, then Net Sales for such Combination Product shall be calculated as (i) [**] percent ([**]%) of actual Net Sales if neither (ii) nor (iii) applies;
(ii) the percentage of Net Sales (or formula to calculate such percentage) mutually agreed in writing by the Parties in advance of First Commercial Sale, if the Parties mutually agree in writing to such percentage (or formula to calculate such
percentage); and (iii) if the Parties have failed to agree on such percentage in writing within [**] days after Arsanis in writing requests discussions, and Adimab has prior to such time undergone an Adimab Change of Control, then the
percentage of Net Sales determined in baseball arbitration under Section 10.2(b). Arsanis shall have no right to refer the matter for dispute resolution or baseball arbitration under Section 10.2(b) unless Adimab has undergone an Adimab
Change of Control prior to the First Commercial Sale of the applicable Product in the applicable country. 

  
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 (d) Adjustment for Compulsory License. If a compulsory license is granted to a Third Party
with respect to any Product in any country in the Territory with a royalty rate lower than the applicable royalty rate set forth in this Section 4.5, and this results in a sublicense by Arsanis or its Affiliate to the compulsory licensee in a
country and with respect to a Product for which the Royalty Election has been made, then the royalty rate to be paid by Arsanis on Net Sales in that country by the compulsory licensee will be reduced to the rate paid by the compulsory licensee. The
royalty rate on Net Sales of such Product by entities other than the compulsory licensee in such country shall be unaffected by the compulsory license. 

(e) Other Royalty Provisions. Only one royalty will be due with respect to the same unit of Product, even if such Product unit is
comprised of more than one Licensed Antibody or any modified or derivative forms thereof. No royalties will accrue on the sale or other disposition of the Product by Arsanis or its Affiliates, licensees or sublicensees for use in a clinical study
sponsored or funded by Arsanis or its Affiliates, licensees or sublicensees or on the disposition of a Product in reasonable quantities by Arsanis or its Affiliates, licensees or sublicensees as free samples (for promotion or otherwise) or as
charitable donations (for example, to non-profit institutions or government agencies for no monetary consideration for a non-commercial purpose). 

4.6 Payment Timings. All Net Sales royalties due under Section 4.5 shall be paid quarterly, on a country-by-country basis, within
[**] days after the end of the relevant calendar quarter for which royalties are due. 
 4.7 Royalty Payment Reports. With
respect to each calendar quarter, within [**] days after the end of the calendar quarter, Arsanis shall provide to Adimab a written report stating the number and description of all Products sold during the relevant calendar quarter; the gross sales
associated with such sales; and the calculation of Net Sales on such sales, including the amount of any deduction provided for in the definition of Net Sales in Article 1. The report shall provide all such information on a country-by-country and
Product-by-Product basis. If applicable Arsanis shall also include in these reports a statement of all Program Transaction Revenue share payments due for the quarter, showing the calculation of the total consideration received in connection with
Program Transactions for which the Revenue Election has been made, any and all deductions in accordance with the definition of Program Transaction Revenue (with supporting detail), net Program Transaction Revenue, and Adimab’s share. Program
Trade Sale Proceeds from Arsanis Trade Sales, and the calculation of such Program Trade Sale Proceeds, shall similarly be included in these reports. 

4.8 Payment Method. All payments due under this Agreement to Adimab shall be made by bank wire transfer in immediately available funds
to an account designated by Adimab. All payments hereunder shall be made in the legal currency of the United States of America, and all references to “$” or “dollars” shall refer to United States dollars (i.e., the
legal currency of the United States). 

  
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 4.9 Taxes. Arsanis shall be responsible to pay and may withhold from payments made to
Adimab under this Agreement any taxes required to be withheld by Arsanis under applicable law. Accordingly, if any such taxes are levied on such payments due hereunder (“Withholding Taxes”), Arsanis shall (a) deduct the
Withholding Taxes from the payment amount, (b) pay all applicable Withholding Taxes to the proper taxing authority, and (c) send evidence of the obligation together with proof of tax payment to Adimab within [**] days following that tax
payment. 
 4.10 Records; Inspection. 

(a) Each Party and its relevant Affiliates, licensees and sublicensees (“Related Parties”) shall keep and maintain (in
conformity with the Accounting Standards), for a period of [**] calendar years following the end of each calendar year during the term of this Agreement, complete and accurate records to enable amounts payable under this Agreement to be determined.
Each Party (the “Auditing Party”) shall have the right, [**] and [**] with respect to the records for any given accounting period, to have an independent, certified public accounting firm reasonably acceptable to the other Party
(the “Audited Party”) review any such records in the location(s) where such records are maintained by the Audited Party or any of its relevant Related Parties upon reasonable notice (which shall be no less than [**] days prior
written notice) and during regular business hours for the sole purpose of verifying the basis and accuracy of payments under this Agreement within the [**] most recent calendar years as of the date of the request for review. Prior to any review, the
independent certified public accounting firm shall have entered into a written agreement with the Audited Party or its relevant Related Parties limiting the use of such records to verification of the accuracy of payments due under this Agreement and
prohibiting the disclosure of any information contained in such records to a Third Party for any purpose and to the Auditing Party for a purpose other than as set forth in this Section 4.10. The report of such accounting firm shall be limited
to a certificate stating whether any report made or invoice or payment submitted by the Audited Party during such period is accurate or inaccurate and the actual amounts owed by or due under this Agreement to the Auditing Party for such period.
After review of the certified public accounting firm’s report, the Audited Party shall promptly pay any understated amounts due to the Auditing Party, together with any interest owed thereon pursuant to Section 4.14. Any overpayment made
by a Party shall be fully creditable against amounts payable in subsequent payment periods or promptly refunded, at the overpaid Party’s election. Any review or audit by an independent certified public accounting firm under this
Section 4.10 is to be made at the expense of the Auditing Party, except that if the results of the review reveal that the Audited Party has underpaid (or in the case where Adimab is the Audited Party, overbilled) by [**] percent ([**]%) or more
for the period under review, then the reasonable costs of such audit shall be paid promptly by the Audited Party. 
 (b) The
Parties agree that, as between Adimab and Arsanis, (x) all information provided in a royalty payment report, all records kept by Arsanis or any relevant Related Party of Arsanis under Section 4.10, and any information provided by the
independent certified public accounting firm to Adimab arc Confidential Information of Arsanis, and (y) vice versa for Adimab regarding the records kept by it and its Related Parties and the information reported by the
independent certified public accounting firm to Arsanis. 

  
 31 

 (c) Notwithstanding subsection (a), any audit of Adimab FTE records shall occur within
[**] after the end of the calendar year to which the records relate or shall be deemed irrevocably waived. 
 4.11
Licensee/Sublicensee Reports, Records and Audits. If Arsanis grants any Product licenses or sublicenses, the agreements for such licenses and sublicenses shall include an obligation for the sublicensee to (a) maintain records
adequate to document and verify the proper payments (including milestones and royalties) to be paid to Adimab; (b) provide reports with sufficient information to allow such verification; and (c) allow Adimab (or Arsanis if requested by
Adimab) to verify the payments due (however, such audit right is not required to be any stronger than that of Section 4.10). 

4.12 Foreign Exchange. If any currency conversion shall be required in connection with the calculation of amounts payable hereunder,
such conversion shall be made using the rate of exchange (a) used by Arsanis (or the selling entity) for its own financial reporting purposes in its worldwide accounting system (which shall be consistent with Accounting Standards) prevailing on
the third to the last Business Day of the month preceding the month in which such sales are recorded, if Arsanis (or the selling entity) is a public company; or (b) if Arsanis is not a public company, then shall be determined the same way
except that the rates shall be the average of the purchase and sale rates for U.S. Dollars for such day as reported by The Wall Street Journal, Eastern Edition. With any payment in relation to which a currency conversion is performed
to calculate the amount of payment due, Arsanis shall provide to Adimab a true, accurate and complete copy of the exchange rates used in the calculation. 

4.13 Non-refundable, non-creditable payments. Each payment that is required under this Agreement is non-refundable and
non-creditable. 
 4.14 Late Payments. Any amount owed by a Party to the other Party under this Agreement that is not paid
within the applicable time period set forth herein will accrue interest at the rate of [**] percent ([**]%) per month compounded monthly, or, if lower, the highest rate permitted under applicable law. 

ARTICLE 5 
 INTELLECTUAL
PROPERTY 
 5.1 Program Patent Ownership. Other than (a) Program Patents that claim Adimab Platform/Core Technology
Improvements, (b) Antibody Sequence Coverage, and (c) Epitope Patents, Program Patents shall be owned based on inventorship. Adimab shall solely own, regardless of inventorship, all Program Patents that claim Adimab Platform/Core
Technology Improvements and, until and unless Arsanis exercises the Option for a given Target, the Antibody Sequence Coverage on all Program Antibodies to such Target {provided, however, that Arsanis shall not practice the
Antibody Sequence Coverage in activities that are outside the scope of the license to Arsanis in Section 3.3). Arsanis shall solely own, regardless of inventorship, the Epitope Patents, Patents on Broad Non-CDR Antibody Inventions, and from and
after the date that Arsanis exercises the Option for a given Target, the Antibody Sequence Coverage on the Licensed Antibodies to such Target (but, to be clear, not the Antibody Sequence  

  
 32 

 
Coverage on the other Program Antibodies to such Target). Program Know-How that constitutes Adimab Platform/Core Technology Improvements shall be owned by Adimab and all other Program Know-How
shall be owned by the Party that created it. Notwithstanding Arsanis’ ownership of the Epitope Patents and the Patents on Broad Non-CDR Antibody Inventions (these are owned by Arsanis under the foregoing in this Section because by definition
these are Arsanis sole inventions), and without modifying the definition of Epitope Patents or Patents of Broad Non-CDR Antibody Inventions in case independent claims are filed that would take a given Patent outside the definitions of the foregoing
terms, Arsanis (and those deriving rights from Arsanis) shall not include in any Patent on a Broad Non-CDR Antibody Invention or Epitope Patent any independent claim that is Program Antibody CDR-specific (i.e., that is described by clause
(a) of the definition of Antibody Sequence Coverage), without Adimab’s advance written withholdable consent, but shall—subject to the non-disclosure requirements of Section 5.4(b)(ii) — be entitled to include dependent
Program Antibody CDR-specific claims. 
 5.2 Implementation. 

(a) Assignments. Each Party hereby assigns to the other Party Program Inventions, associated Patents, and Program Know-How as necessary
to achieve ownership as provided in Section 5.1. Each assigning Party shall execute and deliver all documents and instruments reasonably requested by the other Party to evidence or record such assignment or to file for, perfect or enforce the
assigned rights. Each assigning Party hereby appoints the other Party as attorney-in-fact solely to execute and deliver the foregoing documents and instruments if such other Party after making reasonable inquiry does not obtain them from the
assigning Party. Each Party (and its Affiliates) shall perform its activities under this Agreement through personnel who have made a similar assignment and appointment to and of such Party or its Affiliate. Each assigning Party shall make its
relevant personnel (and their assignments and signatures on such documents and instruments) reasonably available to the other Party for assistance in accordance with this Article at no charge. 

(b) Provisions Relating to Program Antibody Patents; Joint Ownership Implementation. 

(i) Program Antibody Patents. Subject to Adimab’s rights under Section 5.2(c), neither Party is entitled to practice or
license any Program Antibody Patent that is not a Licensed Program Antibody Patent without consent of and without a duty of accounting to the other Party; except that (x) Adimab may practice such Program Antibody Patents within the scope of its
license under Section 3.1(b) and (y) Arsanis may practice such Program Antibody Patents within the scope of its license under Section 3.1(a). 

(ii) Licensed Program Antibody Patents. Subject to Adimab’s rights under Section 5.2(c) and the financial obligations set
forth in this Agreement, neither Party is entitled to practice or license any Licensed Program Antibody Patent without consent of and without a duty of accounting to the other Party; except that Arsanis is free to practice or license all Licensed
Program Antibody Patents within the scope of its license for the applicable Licensed Antibodies and Products under Section 3.3 while such license is in effect with respect to such Licensed Antibodies and Products. 

  
 33 

 (iii) Joint Serendipitous Inventions. As regards Joint Serendipitous Inventions and the
Program Patents to the extent claiming them, each Party is entitled to practice and license them without consent of and without a duty of accounting to the other Party in accordance with the co-ownership rights of co-inventors under U.S. law. Each
Party hereby grants all permissions, consents and waivers with respect to, and all licenses under, the Joint Serendipitous Inventions and the Program Patents claiming them, as necessary to achieve throughout the world the nature of joint ownership
rights of the foregoing as described in the foregoing sentence. To avoid doubt, this Section does not imply any permission, consent or waiver with respect to, or license under, any Patent or item of Know-How other than the Joint Serendipitous
Inventions and the Program Patents to the extent claiming them. 
 (c) Reserved Rights for Adimab Antibody Library. Without
limiting any licenses or other rights granted to Arsanis under this Agreement with respect to any Program Antibodies, it is understood and agreed that Adimab is not required to physically remove from its libraries, or to prevent from being included
in future libraries, any Program Antibodies whatsoever, and, accordingly, Arsanis hereby recognizes that Adimab reserves a non-exclusive, worldwide, royalty-free, freely sublicenseable right under Program Antibody Patents: (i) for Program
Antibodies to be included in antibody library(ies) transferred or licensed by Adimab to Third Parties, even recognizing that in such transactions Adimab may transfer physical possession of, knowingly or unknowingly, samples of Program Antibodies
(other than samples of Program Antibodies generated under this Agreement) in conjunction with an antibody library to a Third Party as part of such transactions (and without implying any license from Arsanis to cover clinical development or
commercialization of the Licensed Antibodies of this Agreement by library licensees); and (ii) to conduct any activity with respect to Program Antibodies and Program-Benefited Antibodies that are not Licensed Antibodies;
provided, that Adimab complies with, and arrives at such non-Licensed Antibodies in a manner fully compliant with, Adimab’s covenants and obligations in this Agreement with respect to the independent discovery of antibodies
by Adimab. 
 5.3 Disclosure. During the term of the Agreement, each Party shall promptly disclose to the other Party the
making, conception or reduction to practice of any Program Inventions that would be Covered by Program Antibody Patents, or in Arsanis’ case that are Adimab Platform/Core Technology Improvements (which, to avoid doubt, are assigned to Adimab by
this Agreement) or in Adimab’s case that are Program Inventions that would properly be claimed in an Epitope Patent (which, to avoid doubt, are assigned to Arsanis by this Agreement). Such disclosure shall occur as soon as possible, but in any
case within [**] days after the Party determines such Program Inventions have been invented. To avoid doubt, this Section shall not be read to require Adimab to disclose Program Inventions constituting Adimab Platform/Core Technology Improvements to
Arsanis or to require Arsanis to disclose Program Inventions constituting Broad Non-CDR Antibody Inventions to Adimab. 
 5.4
Patent Prosecution and Maintenance. 
 (a) Adimab Platform/Core Technology and Epitope Patents. Adimab shall have the sole
right (but not the obligation) to file, prosecute, maintain, defend and enforce all Program Patents that claim Adimab Platform/Core Technology Improvements and all Adimab Platform/Background Patents, all at its own expense. Arsanis shall have the
sole right (but not the obligation) to file, prosecute, maintain, defend and enforce all Epitope Patents and Patents on Broad Non-CDR Antibody Inventions, all at its own expense. 

  
 34 

 (b) Program Antibody Patents. 

(i) Arsanis shall have the sole right (but not the obligation) to file and prosecute all Program Antibody Patents, all at
Arsanis’ expense, including the costs of all foreign and PCT filings. Adimab will have the opportunity to review and comment upon any patent applications and correspondence related to preparing and prosecuting such Program Antibody Patents.
Arsanis shall incorporate Adimab’s reasonable comments and shall confer and reasonably discuss with Adimab any concerns Arsanis has with Adimab’s comments and seek to resolve the concerns by mutual agreement. Arsanis shall give Adimab no
less than [**] days to comment on each draft filing or patent office correspondence in connection with the foregoing prosecution. If additional documentation is required in order for Arsanis to exercise its rights under this paragraph, then the
Parties’ respective patent counsel shall reasonably cooperate as to the form of such additional documentation and Adimab shall provide such required additional documentation (which may include a power of attorney). 

(ii) Prior to applicable Option exercise, Arsanis shall not file any Program Antibody Patent that cannot be prevented from publishing,
but shall have the right to file Patents on Broad Non-CDR Antibody Inventions and Epitope Patents regardless of whether or not they can be prevented from publishing; provided, in the case of Patents on Broad Non-CDR Antibody Inventions
and Epitope Patents, that if they cannot be prevented from publishing, they do not disclose Program Antibody sequences. If Arsanis pursuant to the foregoing sentence files any Patents on Broad Non-CDR Antibody Inventions or any Epitope Patents that
in either case contain Program Antibody sequences, then until and unless Arsanis exercises the applicable Option, Arsanis shall timely prevent such Patents from publishing, and after Option exercise Arsanis shall only allow them to publish to the
extent that the Program Antibody sequences that they contain are Licensed Antibody sequences. 
 (iii) If the Option Term for
a Target expires without Arsanis exercising the applicable Option, then to the extent any claims in any Program Antibody Patents Cover Program Antibodies to such Target (and no other Program Antibodies that may become Licensed Antibodies), such
claims shall be abandoned, Arsanis shall no longer have the right to file, prosecute or maintain such claims, and without Arsanis’ prior written consent Adimab may not use any Confidential Information or Program Know-How of Arsanis, or any
Arsanis Program Inventions, or (unless independently developed) any Program Know-How of Adimab, to seek any claims in any Patents directed to Program Antibodies. 

(c) Licensed Program Antibody Patents. If Arsanis exercises the Option as to any Target then the following applies to all Licensed
Program Antibody Patents that Cover Program Antibodies to such Target: 
 (i) Arsanis will use Commercially Reasonable Efforts
to prepare, file and prosecute the Licensed Program Antibody Patents. Arsanis shall not be entitled, in the Licensed Program Antibody Patents, to seek claims directed to Program Antibodies other than Licensed Antibodies. Adimab will have the
opportunity to review and comment upon any patent 

  
 35 

 
applications and correspondence related to preparing and prosecuting such Licensed Program Antibody Patents. Arsanis shall use Commercially Reasonable Efforts to prepare and prosecute with the
goal of obtaining issued valid coverage for the Licensed Antibodies through the Licensed Program Antibody Patents to the extent reasonably possible to obtain. Arsanis shall incorporate Adimab’s comments to the extent they are reasonable and
reasonably consistent with such goal and shall confer and reasonably discuss with Adimab any concerns Arsanis has with Adimab’s comments and seek to resolve the concerns by mutual agreement. Arsanis shall give Adimab no less than [**] days to
comment on each draft filing or patent office correspondence in connection with the foregoing prosecution. 
 (ii) Arsanis shall
cause to be filed and shall maintain at least one (1) Licensed Program Antibody Patent in the Major Markets and all other countries where consistent with Commercially Reasonable Efforts to do so. 

(iii) It is understood and agreed that searching for, identification and evaluation of Third Party Patents that may apply to any
Program Antibodies based on sequence, Target or the like is the responsibility of Arsanis and Adimab shall have no responsibility for the foregoing nor liability if any such Third Party Patents exist. However, Adimab shall be fully responsible and
liable for any breach of any representation and warranty by it with respect to Third Party Patents as set forth in Article 7, without implying any representation or warranty not set forth in such Article 7. 

(d) Serendipitous Program Inventions. 

(i) Adimab Program Inventions. As between the Parties, Adimab shall have the sole right, at its sole expense and in its sole
discretion, to prepare, file, prosecute, enforce and maintain (including conducting or participating in interferences and oppositions) all Program Patents claiming Adimab Program Inventions but not falling within the Program Antibody Patents, the
Adimab Platform/Core Technology Improvements or Epitope Patents (which, to avoid doubt, are all addressed above). 
 (ii) Arsanis
Program Inventions. As between the Parties, Arsanis shall be responsible, at its sole expense and in its sole discretion, to prepare, file, prosecute, enforce and maintain (including conducting or participating in interferences and oppositions)
all Program Patents claiming Arsanis Program Inventions, but not falling within the Program Antibody Patents, Adimab Platform/Core Technology Improvements or Epitope Patents (which, to avoid doubt, are all addressed above). 

(iii) Serendipitous Joint Program Inventions. The Parties shall mutually agree which of them shall be responsible for either using its
in-house patent attorneys or through mutually agreed upon outside counsel to prepare, file, prosecute, enforce and maintain Program Patents on Joint Serendipitous Inventions, and how the costs of such activities will be shared. 

5.5 Patent Term Restoration. The Parties shall cooperate with each other, including by providing necessary information and assistance
as the other Party may reasonably request, to obtain patent term restoration or supplemental protection certificates or their equivalents in any country where applicable to Licensed Program Antibody Patents. After Option exercise, if elections with
respect to obtaining such patent term restoration are to be made with respect to Licensed Program Antibody Patents and the Parties do not agree, [**]. 

  
 36 

 5.6 Cooperation of the Parties. At the reasonable request of the responsible (as provided
for in this Article 5) Party, the other Party agrees to cooperate fully in the preparation, filing, prosecution, enforcement and maintenance of any Program Patents under this Agreement. Such cooperation includes executing all papers and instruments
(or causing its personnel to do so) reasonably useful to enable the other Party to apply for and to prosecute patent applications in any country; and promptly informing the other Party of any matters coming to such Party’s attention that may
affect the preparation, filing, prosecution, enforcement or maintenance of any such Patents. 
 5.7 Infringement of Patents by
Third Parties. 
 (a) Notification. Each Party shall promptly notify the other Party in writing if the notifying Party
reasonably believes that any Licensed Program Antibody Patent is being or has been infringed or misappropriated by a Third Party (such infringement, together with any that may be imminently threatened to occur by any potential generic version of a
Product arising under the implementing procedures of 35 U.S.C. 271(e)(2) or ex-U.S. equivalent, “Infringement”, and “Infringe” shall be interpreted accordingly). 

(b) License-Competitive Infringement of Licensed Program Antibody Patents. 

(i) First Right. Arsanis shall have the first right, but not the obligation, to enforce the Licensed Program Antibody Patents against
Infringement through [**] (“License-Competitive Infringement”). Arsanis shall reasonably consider Adimab’s comments on any such enforcement activities. Except as provided in subsection (d) or in Section 5.8, Arsanis
shall bear all costs and expenses for enforcement under this Section 5.7(b)(i) (including the reasonable costs of Adimab’s cooperation as required under subsection (d)). 

(ii) Back-up Right for License-Competitive Infringement of Licensed Program Antibody Patents. If Arsanis does not bring action to
prevent or abate License-Competitive Infringement within [**] after notification thereof to or by Arsanis pursuant to Section 5.7(a), then Adimab shall have the right, but not the obligation, to bring, at its own expense, an appropriate action
against any person or entity engaged in such License-Competitive Infringement directly or contributorily. [**]. 
 (iii)
Proceeds. Recoveries on suits under this Section 5.7(b) will be handled as provided in Section 5.8. 
 (c)
Non-License-Competitive Infringement. With respect to any Infringement of Licensed Program Antibody Patents anywhere in the world to the extent relevant to the development, making, using, selling or offering for sale of products containing
Program Antibodies or Program-Benefited Antibodies that are in each case not Licensed Antibodies and involving a competing product (and provided that Adimab complies with, and arrives at such non-Licensed Antibodies in a manner fully compliant with,
Adimab’s covenants and obligations 

  
 37 

 
in this Agreement with respect to the independent discovery of antibodies by Adimab), Adimab shall have the exclusive right (but not the obligation) to prevent or abate such Infringement, and as
between the Parties shall bear all related expenses and retain all related recoveries. In that case, Adimab shall notify Arsanis of such Infringement and keep Arsanis reasonably informed with respect to the disposition of any action taken in
connection with them. 
 (d) Participation of the other Party with Respect to Infringement Suits. If a Party brings an action against
Infringement under this Section 5.7, the other Party shall be entitled to separate representation in such matter by counsel of its own choice and at its own expense, and such Party shall cooperate fully with the Party bringing such action
including by being joined as a party plaintiff if necessary to obtain standing for such action (all at the expense on a pass-through basis of the prosecuting Party). 

(e) Settlement. Adimab shall not settle a claim brought under this Section 5.7 involving Licensed Program Antibody Patents in a
manner that would limit or restrict the ability of Arsanis to develop, make or sell Products for use in the Field, or impair the exclusivity of Arsanis’ license rights, under this Agreement, in each case without the prior written consent of
Arsanis (which consent shall not be unreasonably withheld, conditioned or delayed). Arsanis shall not settle a claim brought under this Section 5.7 involving Licensed Program Antibody Patents in a manner that would limit or restrict the ability
of Adimab to sell, practice, license and fully enjoy the benefits of Adimab’s rights in and to the Licensed Program Antibody Patents as provided in this Agreement or that shortens the life of the Licensed Program Antibody Patents or that would
narrow their scope, in each case without the prior written consent of Adimab (which consent shall not be unreasonably withheld, conditioned or delayed). 

5.8 Allocation of Proceeds. If monetary damages are recovered from any Third Party in an action brought by a Party under
Section 5.7(b), such recovery shall be allocated first to the reimbursement of any costs and expenses incurred by the Party controlling such litigation (including, for this purpose, a reasonable allocation of expenses of internal counsel or
other personnel acting in such capacity (i.e., coordination of litigation matters and the like)), to the extent not previously reimbursed, and then the same costs and expenses of the non-controlling Party, and any remaining amounts shall be split as
follows: 
 (i) if any portion of any such remaining amounts represents recoveries in relation to Infringement other than
License-Competitive Infringement, such portion shall be allocated to Adimab. 
 (ii) if Arsanis exercised its first right to
bring the suit, then the rest of the remaining recovery shall be allocated [**] percent ([**]%) to Adimab and [**] percent ([**]%) to Arsanis; and  

(iii) if instead Adimab exercised its back-up right to enforce, then the rest of the remaining recovery shall be allocated [**]
percent ([**]%) to Adimab and [**] percent ([**]%) to Arsanis. 
 5.9 Patent Challenges. [**] the [**] or [**] or [**], then:
[**]; and [**] shall [**] basis [**] for [**] in connection with [**]. 

  
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 ARTICLE 6 

CONFIDENTIALITY; PUBLICITY. 

6.1 General. Any and all information disclosed or submitted in writing or in other tangible form — or if disclosed orally, that is
indicated to be confidential at the time of disclosure and confirmed in writing as such within [**] days after initial disclosure — to one Party by the other Party under this Agreement or that certain Mutual Confidential Disclosure Agreement
between them dated 8 March 2011, or disclosed between the Parties in the course of negotiating this Agreement or the term sheet for this Agreement whether or not reduced to writing if disclosed orally, is the “Confidential
Information” of the disclosing Party. In addition, information embodied in Adimab Materials is Adimab’s Confidential Information, and information embodied in the Arsanis Materials is Arsanis’ Confidential Information. Sequence
data (whether as to amino acid sequence or nucleic acid sequence) as to Program Antibodies shall be deemed the Confidential Information of Adimab, except that (a) sequence data and data generated in the Collaboration by Adimab relating to
Program Antibodies shall also be the Confidential Information of Arsanis prior to the expiration of the Option Term for the Target to which such Program Antibodies are directed and (b) sequence data and data generated in the Collaboration by
Adimab relating to Licensed Antibodies shall be the Confidential Information of Arsanis and not the Confidential Information of Adimab. Each Party shall receive and maintain the other Party’s Confidential Information in strict confidence.
Neither Party shall disclose any Confidential Information of the other Party to any Third Party. Neither Party shall use the Confidential Information of the other Party for any purpose other than as required to perform its obligations or in the
reasonable exercise of its rights hereunder. Each Party may disclose the other Party’s Confidential Information to the receiving Party’s directors, employees, consultants and contractors requiring access thereto for the purposes of this
Agreement, provided, however, that prior to making any such disclosures, each such person shall be bound by written agreement to maintain Confidential Information in confidence and not to use such information for any purpose
other than in accordance with the terms and conditions of this Agreement. [**] (the “Purpose”). Each Party agrees to take all steps necessary to ensure that the other Party’s Confidential Information shall be maintained in
confidence including such steps as it takes to prevent the disclosure of its own proprietary and confidential information of like character. Each Party agrees that this Agreement shall be binding upon its Affiliates, and upon the employees and
contractors involved in the Research Program of such Party and its Affiliates. Each Party shall take all steps necessary to ensure that its Affiliates and employees and contractors shall comply with the terms and conditions of this Agreement. The
foregoing obligations of confidentiality and non-use shall survive, and remain in effect for a period of [**] years from, the termination or expiration of this Agreement in accordance with Article 9. 

6.2 Exclusions from Nondisclosure Obligation. The nondisclosure and nonuse obligations in Section 6.1 shall not apply to any
Confidential Information to the extent that the receiving Party can establish by competent written proof that it: 
 (a) at the
time of disclosure is publicly known; 
 (b) after disclosure, becomes publicly known by publication or otherwise, except by
breach of this Agreement by such Party; 

  
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 (c) was in such Party’s possession in documentary form at the time of disclosure
hereunder; 
 (d) is received by such Party from a Third Party who has the lawful right to disclose the Confidential
Information and who shall not have obtained the Confidential Information either directly or indirectly from the disclosing Party; or 

(e) is independently developed by such Party (i.e., without reference to Confidential Information of the disclosing Party). 

6.3 Required Disclosures. If either Party is required to disclose any Confidential Information of the other Party, pursuant to a
governmental law, regulation or order, an order of a court of competent jurisdiction; if strictly necessary to defend litigation (meaning that the defense would not be possible if the information were not disclosed); if necessary to prosecute a
litigation under Section 5.7 or between the Parties to establish their rights under this Agreement; or to comply with the rules of the U.S. Securities and Exchange Commission or any stock exchange or listing entity, then the receiving Party may
do so; provided, that the receiving Party shall (i) give advance written notice to the disclosing Party, (ii) make a reasonable effort to assist the disclosing Party to obtain a protective order requiring that the
Confidential Information so disclosed be used only for the purposes for which the law or regulation required, and (iii) use and disclose the Confidential Information solely to the extent required by the law, regulation, order, or rule.

 6.4 Terms of Agreement. The terms of this Agreement are the Confidential Information of both Parties. However, (a) each
Party shall be entitled to disclose the terms of this Agreement to bona fide actual or prospective acquirers, underwriters, investors, lenders or other financing sources (and counsel for the foregoing), (b) Arsanis shall be entitled to disclose
the terms of this Agreement to bona fide actual or prospective Program Transaction counterparties (and counsel for the foregoing), and (c) Adimab shall be entitled to disclose the terms of this Agreement, but excluding financial terms, the
Exhibits to this Agreement and any Research Plan, to actual and prospective Adimab Platform/Core Technology licensees and/or acquirors (and counsel for the foregoing) who, in the case of each of clauses (a)—(c), are obligated to keep such
information confidential and not to use it other than for the Purpose (with “Purpose” being as defined in Section 6.1, both as written there and as applied mutatis mutandis to Adimab as applicable). Moreover, each
Party shall be entitled to disclose the terms of this Agreement to legal, financial and investment banking advisors to the Party, under legally binding obligations of confidentiality and non-use outside of their representation and/or advice to the
Party. In addition, if legally required, a copy of this Agreement may be filed by either Party with the SEC (or relevant ex-U.S. counterpart). In that case, the filing Party will if requested by the other Party diligently seek confidential treatment
for terms of this Agreement for which confidential treatment is reasonably available, and shall provide the non-filing Party reasonable advance notice of the terms proposed for redactions and a reasonable opportunity to request that the filing Party
make additional redactions to the extent confidential treatment is reasonably available under the law. 
 6.5 Return of
Confidential Information. Promptly after the termination or expiration of this Agreement for any reason, each Party shall return to the other Party all tangible manifestations of such other Party’s Confidential Information at that time in
the possession of the receiving Party. 

  
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 6.6 Publicity. The Parties have agreed to the joint press release regarding this Agreement
attached as Exhibit E and shall release it after the signing of this Agreement on a timeline mutually agreed by the Parties. Each Party understands that this Agreement is likely to be of significant interest to investors, analysts and others and,
therefore, that either Party has the right to make announcements of events or developments with respect to this Agreement that are material to such Party. The Parties agree that any such announcement will not contain Confidential Information or, if
disclosure of Confidential Information is required by law or regulation or the rules of the U.S. Securities and Exchange Commission, any stock exchange or listing entity, will make reasonable efforts to minimize such disclosure and obtain
confidential treatment for any such information that is disclosed to a government agency. Each Party agrees to provide the other Party with a copy of any public announcement as soon as reasonably practicable prior to its scheduled release. Except in
the case of extraordinary circumstances, each Party will provide the other with an advance copy of any announcement at least [**] days prior to its scheduled release. Each Party has the right to expeditiously review and recommend changes to any
announcement regarding this Agreement, provided that such right of review and recommendation will only apply for the first time that specific information is disclosed and will not apply to the subsequent disclosure of substantially similar
information that has been previously disclosed. The Parties recognize the importance of announcing when antibodies discovered using the Adimab platform enter the clinic, and that Adimab shall entitled to disclose when Licensed Antibodies under this
Agreement enter the clinic, in press releases mutually agreed by the Parties. Arsanis shall not unreasonably withhold its consent to the manner in which Adimab proposes to make disclosures that Licensed Antibodies have entered the clinic. Arsanis
recognizes that Adimab at times has a practice of grouping announcements as to accomplishments in relation to multiple of its collaborations together into a single press release, and, if Arsanis-related accomplishments are being included in such a
broader press release, Arsanis shall only have the right to approve the wording of those portions of the release that relate to Arsanis. 

6.7 Certain Data. Notwithstanding this Article 6, without disclosing Arsanis’ identity, the identity, nature or class of any
Target (other than the specific Target descriptions set forth on Exhibit F), or the potential indications or class of indications, Adimab shall be entitled to disclose the following Program Antibody attributes: [**]. 

6.8 Publication. Arsanis may publish or present the results of the Collaboration and/or the results of evaluation of Licensed
Antibodies (including during the applicable Option Terms), in each case solely with respect to Licensed Antibodies and/or their Target(s), subject to the prior review and approval by Adimab for patentability and protection of Adimab’s
Confidential Information as provided in this Section 6.8 and without disclosing sequence information that is Adimab’s Confidential Information (and subject to Section 6.2) unless approved of in advance in writing by Adimab in its sole
discretion. Arsanis will provide to Adimab the opportunity to review any proposed abstracts, manuscripts or summaries of presentations that cover such results. Adimab will designate a person or persons who will be responsible for reviewing such
publications. Such designated person will respond in writing promptly and in no event later than [**] days after receipt of the proposed material with either 

  
 41 

 
approval of the proposed material or a specific statement of concern, based upon either the need to seek patent protection or delete Adimab Confidential Information or concern regarding
competitive disadvantage arising from the proposal. In the event of concern, Arsanis agrees not to submit such publication or to make such presentation that contains such information until Adimab is given a reasonable period of time (not to exceed
[**] days) to seek patent protection for any material in such publication or presentation that it believes is patentable and that it has the right to patent, or to resolve any other issues, and Arsanis will remove from such proposed publication any
Confidential Information of Adimab as requested by Adimab. 
 ARTICLE 7 

REPRESENTATIONS AND WARRANTIES. 

7.1 Mutual. Each of Adimab and Arsanis hereby represents and warrants to the other of them that the representing and warranting Party
is duly organized in its jurisdiction of incorporation; that the representing and warranting Party has the full power and authority to enter into this Agreement; that this Agreement is binding upon the representing and warranting Party; that this
Agreement has been duly authorized by all requisite corporate action within the representing and warranting Party; and that the execution, delivery and performance by the representing and warranting Party of this Agreement and its compliance with
the terms and conditions hereof does not and shall not conflict with or result in a breach of any of the terms and conditions of or constitute a default under (a) any agreement or other instrument binding or affecting it or its Affiliate or the
property of either of them, (b) the provisions of its bylaws or other governing documents or (c) any order, writ, injunction or decree of any governmental authority entered against it or by which any of its property is bound. 

7.2 Adimab. Adimab hereby represents, warrants and covenants to Arsanis that: 

Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of 2 pages were omitted. [**]. 

7.3 Arsanis Covenant. [**] to [**] and [**] of [**], and the [**] as [**] in the [**] or [**] and [**], and [**] and [**]
for the [**] in the [**] and [**] with [**]. 
 7.4 DISCLAIMER OF WARRANTIES. OTHER THAN THE EXPRESS WARRANTIES OF SECTIONS 7.1, 7.2
AND 7.3, EACH PARTY DISCLAIMS ALL WARRANTIES OF ANY KIND, EXPRESS OR IMPLIED, INCLUDING ANY WARRANTY OF MERCHANTABILITY OR FITNESS FOR A PARTICULAR PURPOSE OR THAT ANY PRODUCTS DEVELOPED UNDER THIS AGREEMENT ARE FREE FROM THE RIGHTFUL CLAIM OF ANY
THIRD PARTY, BY WAY OF INFRINGEMENT OR THE LIKE, OR THAT ANY PROGRAM PATENTS WILL ISSUE OR BE VALID OR ENFORCEABLE, OR THAT THE DEVELOPMENT, MANUFACTURE OR COMMERCIALIZATION OF ANY PRODUCT PURSUANT TO THIS AGREEMENT WILL BE SUCCESSFUL. 

  
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 ARTICLE 8 

INDEMNIFICATION 
 8.1 By
Adimab. Adimab hereby agrees to indemnify, defend and hold harmless (collectively, “Indemnify”) Arsanis, its Affiliates and its and their directors, officers, agents and employees (collectively, “Arsanis
Indemnitees”) from and against any and all liability, loss, damage or expense (including without limitation reasonable attorneys fees) (collectively, “Losses”) they may suffer as the result of Third Party claims, demands
and actions (collectively, “Third-Party Claims”) to the extent arising out of or relating to both (x) activities under this Agreement or a grant or exercise of rights granted under this Agreement and (y) any of
(a) any material breach of any of Adimab’s obligations under this Agreement or any breach (whether or not material) of a representation, warranty or covenant made by Adimab under Article 7; (b) the negligence or intentional misconduct
of Adimab Indemnitees; or (c) research, testing, development, manufacture, use, sale, distribution, licensing and/or commercialization of any Program Antibodies and/or Products (or Program-Benefited Antibodies or products incorporating them) by
Adimab, its Affiliates or any entity(ies) deriving rights from any of them after a reversion, transfer or grant of rights with respect to the foregoing from Arsanis under Article 9 or pursuant to the exercise of Adimab’s rights under Sections
2.9 and/or 5.2(c); except in each case to the extent of any Losses (i) [**]. 
 8.2 By Arsanis. Arsanis hereby agrees that it,
its Affiliates and all Program Transaction counterparties shall Indemnify Adimab, its Affiliates and its and their directors, officers, agents and employees (collectively, “Adimab Indemnitees”) from and against any and all Losses
they may suffer as the result of Third-Party Claims to the extent arising out of or relating to both (x) activities under this Agreement or a grant or exercise of rights granted under this Agreement (but in the case of
(c)–(g) excluding the grant or exercise of Adimab’s rights under Sections 2.9, 5.2(c) or 9.6) and (y) any of (a) any material breach of any of Arsanis’ obligations under this Agreement or any breach (whether or not
material) of a representation, warranty or covenant made by Arsanis under Article 7; (b) the negligence or intentional misconduct of Arsanis Indemnitees; (c) research, testing, development, manufacture, use, sale, distribution, licensing
and/or commercialization of Licensed Antibodies and/or Products (or Program-Benefited Antibodies or products incorporating them) by or for Arsanis, its Affiliate or any entity deriving rights from any of them; (d) Target-related intellectual
property (including Patents directed to antibodies based on their interaction with any Target); (e) Target-related or Arsanis Materials-related contractual obligations of Arsanis and its Affiliates; (f) intellectual property applying to
any Program Antibody or Program-Benefited Antibody based on its sequence or other characteristics (it being understood and agreed in accordance with Section 5.4(c)(vi) that Adimab does not perform intellectual property searches on Program
Antibodies (including sequence-based searches) and this is the responsibility of Arsanis); or (g) intellectual property relevant to any “optional” (as described in the last paragraph of Section 2.2(d)) activities identified in
the Research Plan(s) (including any and all antibody humanization-related Patents but excluding Adimab’s activities relating to affinity maturation or evolution of cross-reactivity); except in each case to the extent of any Losses (i) [**].

  
 43 

 As regards Third Parties deriving rights from Arsanis or its Affiliate under this Agreement, it shall be
sufficient that each such Third Party provide the foregoing indemnification solely with respect to the activities and scope of rights that are within the particular Third Party’s scope of rights received from Arsanis or its Affiliate, not the
activities of others independently deriving rights from Arsanis or its Affiliate. 
 8.3 Procedures. Each of the foregoing agreements
to Indemnify is conditioned on the relevant Adimab Indemnitees or Arsanis Indemnitees (a) providing prompt written notice of any Third-Party Claim giving rise to an indemnification obligation hereunder, (b) permitting the indemnifying
Party to assume full responsibility to investigate, prepare for and defend against any such Third-Party Claim, (c) providing reasonable assistance in the defense of such claim at the indemnifying Party’s reasonable expense, and
(d) not compromising or settling such Third-Party Claim without the indemnifying Party’s advance written consent. If the Parties cannot agree as to the application of the foregoing Sections 8.1 and 8.2, each may conduct separate defenses
of the Third-Party Claim, and each Party reserves the right to claim indemnity from the other in accordance with this Article 8 upon the resolution of the underlying Third-Party Claim. 

8.4 Limitation of Liability. EXCEPT TO THE EXTENT SUCH PARTY MAY BE REQUIRED TO INDEMNIFY THE OTHER PARTY UNDER THIS ARTICLE 8
(INDEMNIFICATION) OR AS REGARDS A BREACH OF A PARTY’S RESPONSIBILITIES PURSUANT TO ARTICLE 6 (CONFIDENTIALITY; PUBLICITY), NEITHER PARTY NOR ITS RESPECTIVE AFFILIATES SHALL BE LIABLE FOR ANY SPECIAL, INDIRECT, EXEMPLARY, CONSEQUENTIAL OR
PUNITIVE DAMAGES ARISING OUT OF OR RELATED TO THIS AGREEMENT OR THE EXERCISE OF ITS RIGHTS HEREUNDER, WHETHER IN CONTRACT, WARRANTY, TORT, STRICT LIABILITY OR OTHERWISE. 

ARTICLE 9 
 TERM.

 9.1 Term. The term of this Agreement shall commence on the Effective Date and shall expire upon (a) the expiration of the
last Option (if it expires unexercised), or (b) if later, on a country-by-country basis on the expiration of the last Royalty Term for a Product in the particular country, in each case, unless earlier terminated by a Party as set forth below in
this Article 9. On expiration under (b) in the particular country, the license of Section 3.3 for the corresponding Product and its Licensed Antibody shall automatically convert to be perpetual, irrevocable, non-exclusive and fully-paid in
such country. 
 9.2 Material Breach. 

(a) Either Party may terminate this Agreement for the material breach of this Agreement by the other Party, if such breach remains
uncured [**] days following notice from the nonbreaching Party to the breaching Party specifying such breach; provided, however, that if cure of such breach cannot reasonably be effected within such [**] day period, the
breaching party may deliver to the nonbreaching Party a plan reasonably calculated to cure such breach within a timeframe that is reasonably prompt in light of the circumstances then prevailing but in no event longer than an additional [**] days.
Following delivery of such a plan, the breaching Party will carry out the plan and cure the breach. If there is a good faith dispute as to the existence or cure of a breach or default pursuant to this Section 9.2, all applicable cure periods
will be tolled during the existence of such good faith dispute and no termination for a breach which is disputed in good faith will become effective until such dispute is resolved. 

  
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 (b) For Targets for which the Option has been exercised, the foregoing Section 9.2(a)
applies on a Target basis if there is a material adverse effect of the breach on the rights and obligations under this Agreement with respect to such Target (and its associated Patents, Licensed Antibodies, and Products). Furthermore, if Arsanis is
the breaching Party and the material adverse effect of the breach is limited to a given Target for which the corresponding Option has been exercised, then the termination shall be effective only as to the Target to which the uncured material breach
relates (and its related Patents, Licensed Antibodies and Products). If the material breach has, or is reasonably likely to have, a material adverse effect only on the development, manufacture or commercialization of a Product in a particular
jurisdiction or jurisdictions, then this Agreement shall not terminate with respect to such Product and associated Target in the Territory outside of such jurisdiction or jurisdictions, and the foregoing obligations shall only apply to the
terminated jurisdiction or jurisdictions. 
 9.3 Elective Termination. Effective no sooner than the end of the Tail Period,
Arsanis may terminate this Agreement in its entirety on three (3) months prior written notice to Adimab. Arsanis may also terminate this Agreement as to all Licensed Antibodies to a particular Target and all Products based on the terminated
Licensed Antibodies by three (3) months prior written notice to Adimab. Such right to terminate on a Target basis shall be exercisable one (1) or more times (at different times for different Targets). 

9.4 Survival in All Cases. Termination of this Agreement shall be without prejudice to or limitation on any other remedies available to
nor any accrued obligations of either Party. In addition, Sections 2.4(c) (except that Section 2.4(c) shall not survive termination by Adimab under Section 9.2 for Arsanis’ uncured material breach), 2.5(a), 2.6, 2.7, 4.3 through 4.14
(with respect to payment obligations outstanding as the effective date of termination or expiration; and in the case of Section 4.3(f) payment obligations for Epitope-Only Transactions after the date of termination or expiration shall continue
to accrue for the life of the Epitope Patents), 5.1, 5.2(a), 5.2(b)(iii), 5.2(c), 5.4(a) and (d)(iii), 7.3, and 7.4 and Articles 1 (to the extent the definitions in such Article are relevant to other surviving provisions of this Agreement or a
covenant is contained in such Article), 6, 8, 9 and 10 shall survive any expiration or termination of this Agreement. 
 9.5
Certain Consequences of Termination. If this Agreement expires or terminates in its entirety (other than an expiration under Section 9.1 following an Option exercise after all Royalty Terms have expired or a termination by Arsanis pursuant
to Section 9.2 for Adimab’s material breach (“Full Payment Term Expiration”)), or in part (e.g., only in certain jurisdictions or only in connection with certain Targets), Arsanis hereby covenants that unless Arsanis
agrees in writing to pay Adimab payments as set forth in Article 4 with respect to products containing a Program-Benefited Antibody as if such products were Products (and as to related transactions as if they were Program Transactions), Arsanis and
its Affiliates shall not (a) develop or commercialize such Program-Benefited Antibody or product containing such Program-Benefited Antibody, (b) license or otherwise grant rights to any entity to do the foregoing, or (c) practice,
license or assign to a Third Party, option to a Third Party or covenant not to sue a Third Party under Licensed Program Antibody Patents with respect to such Program-

  
 45 

 
Benefited Antibody. In the event that Arsanis agrees to pay Adimab payments as set forth in Article 4 with respect to products containing a Program-Benefited Antibody as if such products were
Products (and as to related transactions as if they were Program Transactions), then Adimab shall agree to a covenant not to sue Arsanis with respect to such products and transactions as set forth in Section 3.5(b). Other than after a Full
Payment Term Expiration, if Arsanis has elected under Section 5.1 to include Program Antibody CDR-specific dependent claim(s) in any Epitope Patent or Patent on a Broad Non-CDR Antibody Invention (i.e., a patent claim that would be described by
clause (a) of the definition of Antibody Sequence Coverage but for being a dependent claim (whereas such clause (a) requires an independent claim)), then Arsanis shall not include such dependent claim(s) in any license granted under such
Epitope Patent or Patent on a Broad Non-CDR Antibody Invention. 
 9.6 Additional Effects of Termination for Arsanis Fault or Arsanis
Elective Termination. If Adimab terminates this Agreement for Arsanis’ uncured material breach, or Arsanis terminates this Agreement at-will under Section 9.3, then, as to all Targets (and associated Patents, Licensed Antibodies and
Products) in the jurisdiction(s) for which this Agreement has terminated: Arsanis and its Affiliates (a) hereby assign to Adimab, effective upon such termination, all right, title and interest in and to the Program Patents (other than Program
Patents claiming Broad Non-CDR Antibody Inventions and Epitope Patents, provided that Arsanis, effective upon such termination, hereby grants to Adimab an exclusive, royalty-free, worldwide perpetual license under such Patents claiming Broad Non-CDR
Antibody Inventions and Epitope Patents, to make, have made, use, sell offer to sell, import and export Program Antibodies, Products, Program-Benefitted Antibodies researched, developed or commercialized by Arsanis or its Affiliate prior to the time
of termination, and pharmaceutical compositions containing the foregoing), Program Know-How, and all data with respect to the terminated Licensed Antibodies that are Controlled by Arsanis and its Affiliates; (b) shall transfer all producing
cell lines for such Licensed Antibodies to Adimab (under conditions intended to ensure their viability) along with copies of master batch records and SOPs (if existing) for production of such antibodies; and (c) shall transfer all filings with
Regulatory Authorities with respect to such Licensed Antibodies to Adimab if Adimab requests in writing. If Adimab engages in a Program Transaction (analogously defined) with respect to any of the rights transferred to it under this Section, or it
or its Affiliate markets any Licensed Antibody or Product the rights to which returned to Adimab under this Section 9.6, in each case other than pursuant to any Program Transaction to which Adimab becomes a party under Section 9.8, then
Article 4 (but excluding Sections 4.1-4.2) shall apply mutatis mutandis to require Adimab to make payments to Arsanis in the same amounts and in relation to the same elections, revenues and sales as such Article (excluding such
Sections) provides for Arsanis to pay Adimab. Beyond these payments, Adimab shall not owe any monies to Arsanis in respect of Adimab’s rights under this Section 9.6. Notwithstanding the first sentence of this Section, clauses (a),
(b) and (c) of this Section are subject to the terms of any then-in-effect Program Transactions. 
 9.7 Additional
Effects of Termination for Adimab Fault. If Arsanis elects to terminate this Agreement pursuant to Section 9.2(a), then (a) any unexercised and unexpired Options shall survive, and the “Option Term” for each of these Options
shall continue unaffected by the termination; (b) the licenses and rights granted to Arsanis under Sections 2.6 and 3.1 shall survive termination until the time that in the case of Section 3.1 they would have otherwise expired (and
Arsanis’ rights under Section 2.8 shall survive to the extent necessary or useful to 

  
 46 

 
the determination whether to exercise any continuing Options); (c) the licenses granted under Section 3.3 shall survive with respect to each Target the Option for which was exercised by
Arsanis prior to and after the effective date of termination; provided, that Arsanis complies with its diligence obligations under Section 3.4(a) with respect to such Target and pays all amounts due to Adimab pursuant to Article 4 that
would otherwise be applicable to Licensed Antibodies and/or Products directed to such Target; provided that Arsanis may elect, in its sole discretion upon written notice to Adimab, to either (i) reduce such amounts by the amount of all damages
attributable to Adimab’s breach of this Agreement (as mutually agreed by the Parties or determined by a court or arbitrator of competent jurisdiction) or (ii) change all references to “[**] percent ([**]%)” in Section 4.4 to
“[**] percent ([**]%)” and the royalty rate referred to in Sections 3.3(c)(i) and 4.5 to [**] percent ([**]%), and apply, as a credit against any future payments Arsanis is required to make to Adimab under this Agreement, up to one hundred
percent (100%) of the amount (“Arsanis True-up Amount”) equal to [**] percent ([**]%) of the total amount paid to Adimab under this Agreement with respect to the terminated Target(s) (and their associated Patents, Licensed
Antibodies, and Products) prior to the effective date of such termination until such Arsanis True-up Amount has been applied in full; (d) Arsanis’ obligation to disclose data to Adimab pursuant to Section 6.7 shall terminate; and
(e) Sections 2.9, 5.2(b)(i), 5.2(b)(ii), 5.3, 5.4(b), (d)(i) and (d)(ii), 5.5, 5.6, 5.7, 5.8, 7.1, 7.2, and 7.4 shall survive. 

9.8 Survival of Sublicenses. In the event that the licenses granted to Arsanis under this Agreement are terminated, any granted
sublicenses to Program Transaction counterparties (to avoid doubt, granted to Third Parties, not Arsanis Affiliates) will remain in full force and effect; provided, that the sublicensee is not then in breach of its Program Transaction
agreement and the Program Transaction counterparty agrees to be bound to Adimab as a licensor under the terms and conditions of the Program Transaction agreement (including payment obligations), without imposing any greater obligation on Adimab than
imposed on Adimab under this Agreement. Adimab will enter into appropriate agreements or amendments to the Program Transaction agreement to substitute itself for Arsanis as the licensor thereunder. Regardless of any prior Royalty Election or Revenue
Election made by Arsanis, upon the effective date of such termination the Revenue Election shall apply to any Program Transaction to which Adimab becomes a party under this Section, and the provisions of Sections 4.3(c), (d), and (e) and
Section 4.4 shall apply mutatis mutandis to require Adimab to make payments to Arsanis with respect to such Program Transaction in the same amounts and in relation to the same revenues and sales as such Sections of the Agreement provide
for Arsanis to pay Adimab with respect to Program Transactions subject to the Revenue Election; provided, however, that Adimab may apply, as a credit against any future payments Adimab is required to make to Arsanis under this
Agreement, up to one hundred percent (100%) of the amount (“Adimab True-up Amount”) equal to (i) [**] percent ([**]%) of the total amount of any Program Transaction Revenue, Multi-Product Deal Program Transaction Revenue
or Multi-Target Deal Program Transaction Revenue, as the case may be, received by Arsanis in respect of such Program Transaction under this Agreement prior to the effective date of termination, less (ii) the total amount of any payments
received by Adimab in respect of such Program Transaction under this Agreement prior to the effective date of termination, until such Adimab True-up Amount has been applied in full. To avoid doubt, Adimab is not required to assume any greater
obligations to the Program Transaction counterparty than Adimab’s obligations to Arsanis under this Agreement, other than the obligation to provide a sublicense under the license to Adimab of Section 9.6 under any Patents on Broad Non-CDR
Antibody Inventions and Epitope Patents. 

  
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 9.9 Bankruptcy. All licenses and rights to licenses granted under or pursuant to this
Agreement by Adimab to Arsanis are, and will otherwise be deemed to be, for purposes of Section 365(n) of the United States Bankruptcy Code (the “Bankruptcy Code”), licenses of rights to “intellectual property” as
defined under Section 101(35A) of the Bankruptcy Code. The Parties agree that Arsanis, as a licensee of such rights under this Agreement, will retain and may fully exercise all of its rights and elections under the Bankruptcy Code. The parties
further agree that that upon commencement of a bankruptcy proceeding by or against Adimab under the Bankruptcy Code, Arsanis will be entitled to a complete duplicate of, or complete access to (as Arsanis deems appropriate), all such intellectual
property and all embodiments of such intellectual property. Such intellectual property and all embodiments of such intellectual property will be promptly delivered to Arsanis (a) upon any such commencement of a bankruptcy proceeding and upon
written request by Arsanis, unless Adimab elects to continue to perform all of its obligations under this Agreement, or (b) if not delivered under (a) above, upon the rejection of this Agreement by or on behalf of Adimab and upon written
request by the Arsanis. Adimab (in any capacity, including debtor-in-possession) and its successors and assigns (including any trustee) agrees not to interfere with the exercise by Arsanis or its Affiliates of its rights and licenses to such
intellectual property and such embodiments of intellectual property in accordance with this Agreement, and agrees to assist Arsanis and its Affiliates in obtaining such intellectual property and such embodiments of intellectual property in the
possession or control of Third Parties as reasonably necessary or desirable for Arsanis to exercise such rights and licenses in accordance with this Agreement. The foregoing provisions are without prejudice to any rights Arsanis may have arising
under the Bankruptcy Code or other applicable law. Notwithstanding the foregoing in this Section 9.9, nothing in this Section 9.9 shall be read to entitle Arsanis to obtain disclosure of or access to Adimab Platform/Core Technology
(including Adimab Platform/Core Technology Improvements), whether or not as an “embodiment,” “update,” or otherwise, at any time, and Arsanis shall not under any circumstances notwithstanding anything express or implied in this
Agreement be entitled to disclosure of Adimab Platform/Core Technology (including Adimab Platform/Core Technology Improvements). 

ARTICLE 10 

MISCELLANEOUS. 
 10.1
Independent Contractors. The Parties shall perform their obligations under this Agreement as independent contractors. Nothing contained in this Agreement shall be construed to be inconsistent with such relationship or status. This Agreement and
the Parties’ relationship in connection with it shall not constitute, create or in any way be interpreted as a joint venture, fiduciary relationship, partnership or agency of any kind. 

10.2 Dispute Resolution. 

(a) Escalation. Either Party may refer any dispute in connection with this Agreement to senior executives of the Parties (for Adimab,
an Officer or Board member who is not an Officer, Board member or stockholder in Arsanis or representing a fund that is a stockholder in Arsanis and for Arsanis, an Officer or Board member who is not an Officer, Board member or stockholder in Adimab
or representing a fund that is a stockholder in Adimab) for 

  
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good-faith discussions over a period of not less than [**] days (the “Senior Executives Discussions”). Each Party will make its executives reasonably available for such
discussions. If the Parties are unable to resolve the dispute through the Senior Executives Discussions within such [**] days, then either Party may proceed to seek a judicial resolution of the matter, except that in the case of a dispute or failure
to agree over an allocation of Program Transaction Revenue that is provided in this Agreement not to be subject to baseball arbitration under Section 10.2(b) due to Adimab not having undergone a Change of Control by the applicable
time for the matter to be referable to such baseball arbitration (“Adimab-Reserved Allocation Decisions”), notwithstanding anything express or implied in this Agreement, at law or in equity, the Adimab- Reserved Allocation Decisions
shall not be referable for judicial resolution either, under any circumstance (including in the case of an allegation by Arsanis that Adimab has failed to negotiate in good faith). 

(b) Baseball Arbitration for Selected Financial Allocations. Disputes over the allocation of value described in Sections 4.3 and 4.5(c)
as referable for baseball arbitration under this Section shall be resolved by arbitration as provided in this Section 10.2(b). To avoid doubt, only certain allocation disputes are referable to this Section 10.2(b), and these are only those
allocation disputes as to allocation decisions first arising after an Adimab Change of Control as described more particularly in Section 4.3 or 4.5(c). In the absence of such an Adimab Change of Control at the applicable time the allocation
decision first arises (as described more particularly in Section 4.3 or Section 4.5(c)), Arsanis shall have no right to require baseball arbitration under this Section, notwithstanding anything express or implied in this Agreement, at law
or in equity. 
 (i) The Parties shall jointly engage an arbitrator through JAMS (or its successor) (the
“Arbitrator”). JAMS shall appoint the Arbitrator if the Parties do not agree on which one to select within [**] days. The Parties agree that the arbitrator shall be a lawyer with at least fifteen (15) years experience or a
former judge of a court of general jurisdiction, and shall be experienced in matters regarding issues of a similar nature, and shall be neutral, independent, disinterested, and impartial. 

(ii) If JAMS has any rules specific to baseball arbitration at the time a Party requests the baseball arbitration, then those rules
shall apply. If JAMS does not have any such specific rules, then the most applicable procedural rules of JAMS shall apply. In each case, the applicable rules shall be modified to the extent in conflict with this Section 10.2(b). The place of
arbitration shall be New York, New York or such other place as the parties may mutually agree. 
 (iii) In the case of a
dispute under Section 4.3 or 4.5(c), Arsanis shall disclose to the Arbitrator and to Adimab (if it has not already done so) the texts of all documents governing the Multi-Target Deal, Multi-Product Deal or the Arsanis Trade Sale, as the case
may be. Within [**] days after such disclosure, each Party shall make its detailed proposal as to its calculation of Multi-Product Deal Program Transaction Revenue, Multi-Target Deal Program Transaction Revenue or Program Trade Sale Proceeds, as the
case may be, taking into account the portion of Arsanis Trade Sale proceeds attributable to Undesignated Rights and any Combination Product adjustment that the Party proposes under Section 4.3(e). In the case of a dispute under
Section 4.5(c), each Party shall make a detailed proposal as to the portion of Net  

  
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Sales of the Combination Product that such Party proposes to be royalty-bearing under this Agreement. Each of the foregoing written proposals shall be provided by the Parties within [**] days
after the appointment of the Arbitrator, and each shall not to exceed [**] pages (including supporting materials and explanation). Each Party shall be allowed [**] depositions as part of the discovery process not to exceed [**] hours in the
aggregate (or more if the Arbitrator deems them reasonably necessary), and each Party may perform reasonable document discovery to the extent determined by the Arbitrator. Each Party shall disclose its proposal simultaneously to the other Party and
to the Arbitrator. The Arbitrator may hold hearings including both Parties and in which each Party may make a presentation or present witnesses for no more than [**] hours. The Arbitrator may also question the Parties and hear the Parties’
answers to the Arbitrator’s questions for no more than an additional [**] hours. Neither Party shall engage in ex parte communications with the Arbitrator. The Arbitrator shall choose one of the Parties’ proposals to
become the arbitral award, and shall render his or her decision within [**] days after the Arbitrator is selected. 
 (iv)
The Arbitrator’s selection shall be binding on the Parties with respect to the particular Multi-Product Deal, Multi-Target Deal, Arsanis Trade Sale, or Combination Product adjustment to Net Sales or to Program Transaction Revenue, as the
case may be, absent proven fraud. Each Party shall bear its own costs of arbitration, and the Parties shall share equally the costs for the Arbitrator and the arbitration process, unless the Arbitrator chooses to award costs and attorneys’ fees
to either Party in whole or in part, which the Arbitrator is hereby fully empowered to do. All information disclosed to the Arbitrator or to the other Party by a Party shall be Confidential Information of the disclosing Party (except to the extent
containing Confidential Information previously disclosed hereunder by the other Party). 
 (v) The standards that the
Arbitrator shall apply to the different allocation decisions that are decided by arbitration under this Section are: 
 (1) In
the case of a Multi-Target Deal, the Arbitrator is instructed to choose the proposal that more fairly and reasonably allocates Program Transaction Revenue to the elements of the Multi-Target Deal other than the Unrelated Target component (i.e., to
(a) the Target(s) that are not Unrelated Targets in the particular Program Transaction, (b) antibodies and other drugs against such Target(s), (c) products containing any of the foregoing, (d) Epitope Patents relating to such
Targets, and/or (e) anything (including rights, data, activities and materials) relating to any of the foregoing, all of the foregoing as opposed to and contrasted with (v) the Unrelated Targets in the Multi-Target Deal;
(w) antibodies to such Unrelated Target(s), (x) small molecules or non-antibody drugs (in each case not co-formulated with any of (a)-(c)), (y) products containing any of the foregoing in (v)—(x); and/or (z) anything
(including rights, data, activities and materials) relating to any of the foregoing in (v)—(y)). 
 Multi-Target Deal Program
Transaction Revenue shall be subject to further adjustment applying the standard of subsection (2) if elements (a)—(d) in the foregoing paragraph include rights to antibodies that are neither Licensed Antibodies nor Program-Benefited
Antibodies nor products based exclusively on either or both of the foregoing (i.e., if the deal is, additionally, a Multi-Product Deal). 

  
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 Multi-Target Deal Program Transaction Revenue shall be subject to further adjustment applying the
standard of subsection (3) if the lead Product or any back-up Product in active development in the Multi-Target Deal is a Combination Product. 

The Program Transaction Revenue fairly and reasonably attributable to Epitope Patents shall in any event be included in Multi-Target Deal
Program Transaction Revenue. 
 (2) In the case of a Multi-Product Deal, the Arbitrator is instructed to choose the proposal that
more fairly and reasonably allocates Program Transaction Revenue to the Licensed Antibody, Product, Program-Benefited Antibody, product containing the foregoing, and Epitope Patents components of the Multi-Product Deal, taking into account all of
the following factors: 
 (a) Whether a Licensed Antibody, Program-Benefited Antibody, Product, or product containing a
Program-Benefited Antibody is the lead product candidate in the program; 
 (b) Which antibodies and products in the deal are the
most advanced; 
 (c) With respect to which antibodies and products in the deal significant data have been generated, and how
advanced and favorable such data are; 
 (d) Which antibodies and products in the deal would require further adjustment prior to
being a viable candidate for development (e.g., in the case of antibodies, whether or not they require humanization prior to being considered a product candidate); 

(e) Levels of affinity or other desirable properties vis-à- vis the Target(s) and data as to efficacy; 

(f) Safety characteristics; 

(g) What candidates are planned to have what level of resource put into their development going forward after the Program Transaction
(if such plans are known at that time); 
 (h) Proprietary positions on the different product candidates; 

(i) If not grouped together in a single transaction, and instead sold in separate, unrelated, arms’-length transactions in which
the counterparties are unrelated to each other, which elements included in the Program Transaction would garner the highest prices (and what relative prices would the different elements garner); and 

(j) All other relevant commercial factors. 

  
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 The Arbitrator is instructed that the allocation should not be made purely based on the number of antibodies,
drugs, product candidates and products in the deal that are and are not Licensed Antibodies, Program-Benefited Antibodies, Products and products containing the foregoing. Rather, it should be based upon a qualitative inquiry into which antibodies,
drugs, product candidates and candidates are responsible for the value being realized and monetized in the Program Transaction, and in what proportions. It is anticipated that antibodies, drugs, product candidates and products that are most advanced
in development shall receive allocation of the majority or in some cases all of the Program Transaction Revenue. The Arbitrator shall, in assessing the Parties’ proposed allocations, take into account that it is not necessarily fair or
reasonable to allocate any value to antibodies, drugs, product candidates and products for which no data have been generated. 
 The Program Transaction
Revenue reasonably attributable to Epitope Patents shall in any event be included in Multi-Product Deal Program Transaction Revenue and shall not be subject to reduction or allocation under this subsection (2). 

Where this subsection (2) is being applied as a further adjustment to Multi-Target Deal Program Transaction Revenue, it shall be applied solely to
Multi-Target Deal Program Transaction Revenue (not to all Program Transaction Revenue). 
 (3) If the lead Product(s) and other
Products having undergone active development or that are advanced back-ups in active development in the Program Transaction are Combination Products, then the Arbitrator shall pick the proposal for the formula A/(A+B) that more fairly and reasonably
attributes value to Licensed Antibody components in the Combination Product(s), where “A” is the value contributed by the Licensed Antibody and Program-Benefited Antibody components, and “B” is the value contributed, in the case
of Drug Combinations, by the other active ingredients; in the case of Drug-Device Combinations, by the other active ingredients (if any) and patented delivery device; and in the case of Diagnostic Combinations by the other antibodies in the
Diagnostic Combination (the components listed out here being the “recognized components;” the recognized components shall in any event always exclude inert ingredients and excipients in Drug Combinations and Drug-Device Combinations, as
well as unpatented technology in Drug-Device Combinations). The Arbitrator shall take into account all of the following: 
 (a)
Sales prices of each component when sold separately shall be considered the most reliable indicator of value, if available for each recognized component (as indicated above) in the Combination Product. 

(b) Any active ingredient that is a generic drug or generic biologic shall in general be considered to contribute significantly less
value than proprietary active ingredients. 
 Where this subsection (3) is being applied as a further adjustment to Multi-Target Deal Program
Transaction Revenue, it shall be applied solely to Multi-Target Deal Program Transaction Revenue (not to all Program Transaction Revenue). 

  
 52 

 Where this subsection (3) is being applied as a further adjustment to Multi-Product Deal Program Transaction
Revenue, it shall be applied solely to Multi-Product Deal Program Transaction Revenue (not to all Program Transaction Revenue). 
 This sub-section
(3) shall not be applied to further adjust any value that was attributed to Epitope Patents in an allocation under subsection (1). 

(4) In the case of an allocation in an Arsanis Trade Sale, the Arbitrator shall apply the same standards to allocate revenue to the
Undesignated Rights as used first in Multi-Target Deals, and with further adjustment under subsections (2) and (3) as warranted by the facts. 

(5) In the case of a Combination Product adjustment to Net Sales, the Arbitrator shall select the proposal that more fairly and
reasonably allocates Net Sales of a Combination Product to the Licensed Antibody component(s) of such Combination Product, on the formula A/(A+B), with the remainder of the standard being as described in subsection (3) but applied to Net Sales
rather than Program Transaction Revenue. 
 The page limits and presentation time limits stated in this Section 10.2(b) apply to all allocations being
made with respect to a given Program Transaction or Arsanis Trade Sale, on an aggregate basis. 
 10.3 Governing Law and
Venue. This Agreement shall be governed by and interpreted in accordance with the laws of the State of New York without giving effect to principles of conflicts of laws that would require the application of any other law; provided,
that matters of intellectual property law will be determined in accordance with the United States federal law. Any and all judicial resolutions of disputes in connection with this Agreement shall be in federal court located within any of the
boroughs of New York City, New York, and each Party hereby consents to the jurisdiction and venue of such courts, and waives all defenses it may have to such jurisdiction and venue, including that the court cannot assert personal jurisdiction over
the defendant and forum non conveniens. 
 10.4 Entire Agreement. This Agreement (including its Exhibits) sets forth all the
covenants, promises, agreements, warranties, representations, conditions and understandings between the Parties with respect to the subject matter hereof and supersedes and terminates all prior agreements and understandings between the Parties with
respect to such subject matter (including that certain Mutual Confidential Disclosure Agreement between the Parties dated 8 March 2011). No subsequent alteration, amendment, change or addition to this Agreement shall be binding upon the Parties
unless reduced to writing and signed by the respective authorized officers of the Parties. 
 10.5 Assignment.
Neither Party may assign in whole or in part this Agreement without the advance written consent of the other Party, except as set forth in the following sentence. Either Party may assign this Agreement in its entirety to the successor to all or
substantially all of its stock or assets to which this Agreement relates in connection with its merger with, or the sale of all or substantially all of its stock or assets to which this Agreement relates, to another entity, regardless of the form of
the transaction. In addition, Adimab may  

  
 53 

 
assign this Agreement, or any of its rights under this Agreement, in connection with the sale of, monetization of, transfer of, or obtaining financing on the basis of the payments due to
Adimab under this Agreement or debt or project financing in connection with this Agreement. Also, Arsanis may assign its rights and obligations under this Agreement on a Target-by-Target basis, at any time after Option exercise for the particular
Target, to any entity to which Arsanis assigns all or substantially all of its assets with respect to such Target (and its related Patents, Licensed Antibodies and Products); provided that, to avoid any ambiguity as to what rights and
obligations are being assigned, Adimab shall be entitled to require before the closing of such transaction that a separate document be created and signed between the Parties addressing solely the rights and obligations in relation to such Target
(and its related Patents, Licensed Antibodies and Products) and it shall be only the rights and obligations set forth in such separate document that shall be assigned in the transaction. Subject to the foregoing, this Agreement shall be binding upon
and shall inure to the benefit of the Parties and their respective successors and permitted assigns. Any assignment of this Agreement not made in accordance with this Agreement is prohibited hereunder and shall be null and void. 

10.6 Severability. If one or more of the provisions in this Agreement are deemed unenforceable by law, then such provision shall be
deemed stricken from this Agreement and the remaining provisions shall continue in full force and effect. 
 10.7 Force
Majeure. Both Parties shall be excused from the performance of their obligations under this Agreement to the extent that such performance is prevented by a Force Majeure (defined below) and the nonperforming Party promptly provides notice
of the prevention to the other Party. Such excuse shall be continued so long as the condition constituting Force Majeure continues and the nonperforming Party takes reasonable efforts to remove the condition, but no longer than six (6) months.
For purposes of this Agreement, “Force Majeure” means conditions beyond a Party’s reasonable control or ability to plan for, including acts of God, war, terrorism, civil commotion, labor strike or lock-out;
epidemic; failure or default of public utilities or common carriers; and destruction of production facilities or materials by fire, earthquake, storm or like catastrophe; provided, however, the payment of invoices due and owing under this
Agreement shall not be excused by reason of a Force Majeure affecting the payor. 
 10.8 Notices. Any notice required or
permitted to be given under this Agreement shall be in writing, shall specifically refer to this Agreement and shall be deemed to have been sufficiently given for all purposes if (a) mailed by first class certified or registered mail, postage
prepaid, (b) delivered by express delivery service, (c) personally delivered, or (d) transmitted by facsimile with proof of completed transmission and which notice by facsimile shall be followed reasonably promptly by an additional
notice pursuant to one of clause (a), (b) or (c) above. Unless otherwise specified in writing, the mailing addresses of the Parties shall be as described below. Arsanis will provide its facsimile number by written notice within 60 days
after the Signing Date. 

  
 54 

 If to Adimab: 

Adimab, Inc. 
 16 Cavendish Court

 Lebanon, NH 03766 

Attention: CEO 
 Facsimile: [**]

 with a required copy to each of: 

Attention: Head, Business Development at the same address and fax. 

and 
 Laura O. Spiegelman 

Spiegelman Life Sciences 
 1459
Eighteenth Street – PMB 309 
 San Francisco, CA 94107 

Facsimile: [**] 
 In the case of Arsanis: 

Arsanis, Inc. 
 16 Cavendish Court

 Lebanon, NH 
 Attention:
Chief Scientific Officer 
 with a copy to: 

Sumy C. Daeufer 
 Faber
Daeufer & Rosenberg PC 
 950 Winter Street, Suite 4500 

Waltham, MA 02451 
 Facsimile:
[**] 
 10.9 Construction. This Agreement has been prepared jointly and shall not be strictly construed against either Party.
Ambiguities, if any, in this Agreement shall not be construed against any Party, irrespective of which Party may be deemed to have authored the ambiguous provision. 

10.10 Headings. The headings for each article and section in this Agreement have been inserted for convenience of reference only and
are not intended to limit or expand on, nor to be used to interpret, the meaning of the language contained in the particular article or section. 

10.11 No Waiver. Any delay in enforcing a Party’s rights under this Agreement or any waiver as to a particular default or other
matter shall not constitute a waiver of such Party’s rights to the subsequent enforcement of its rights under this Agreement, excepting only as to an express written and signed waiver as to a particular matter for a particular period of time
executed by an authorized officer of the waiving Party. 

  
 55 

 10.12 Performance by Affiliates. A Party may perform some or all of its obligations under
this Agreement through Affiliate(s) or may exercise some or all of its rights under this Agreement through Affiliates. However, each Party shall remain responsible and be guarantor of the performance by its Affiliates and shall cause its Affiliates
to comply with the provisions of this Agreement in connection with such performance. In particular and without limitation, all Affiliates of a Party that receive Confidential Information of the other Party pursuant to this Agreement shall be
governed and bound by all obligations set forth in Article 6, and shall (to avoid doubt) be subject to the intellectual property assignment and other intellectual property provisions of Article 5 as if they were the original Party to this Agreement
(and be deemed included in the actual Party to this Agreement for purposes of all intellectual property-related definitions). A Party and its Affiliates shall be jointly and severally liable for their performance under this Agreement. 

10.13 Counterparts. This Agreement may be executed in one or more identical counterparts, each of which shall be deemed to be an
original, and which collectively shall be deemed to be one and the same instrument. In addition, signatures may be exchanged by facsimile or PDF. 

[remainder of page intentionally blank] 

  
 56 

 IN WITNESS WHEREOF, the
Parties have by duly authorized persons executed this Agreement as of the date first written above. 
  

									
	ARSANIS, INC.:	 		 	ADIMAB, LLC:
					
	Sign:	 	/s/ Eszter Nagy	 		 	Sign:	 	/s/ Errik Anderson
	Print Name: Eszter Nagy	 		 	Print name: Errik Anderson
	Title: CSO	 		 	Title: COO
	Date: 9/20/2011	 		 	Date: 9/20/2011

  
 57 

 CONFIDENTIAL 

EXECUTION COPY 

EXHIBITS LIST 

A – ADIMAB PLATFORM/BACKGROUND PATENTS 

B – RESEARCH OVERVIEW 

C – RESEARCH PLAN 

D – FORM OF QUESTIONNAIRE 

E – JOINT PRESS RELEASE 

F – PERMITTED TARGET DESCRIPTIONS 

G – EXCERPT FROM ARSANIS ARTICLES 

  
 A-1 

 EXHIBIT A 

BACKGROUND PATENTS 

Adimab Platform / Background Patents 
  

			
	Publication Number	  	Title

 [**] 

  
 A-2 

 EXHIBIT B 

RESEARCH OVERVIEW 

[**] 

  
 B-1 

 EXHIBIT C 

RESEARCH PLAN 1 

Adimab—Arsanis workplan #1 

Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of 26 pages were omitted. 

[**] 

  
 D-1 

 EXHIBIT D 

FORM OF QUESTIONNAIRE 

Partner Completed Target Questionnaire 

Information you are able to provide about your target will help Adimab design a customized selection strategy and detailed work plan. This will ultimately
allow Adimab to deliver antibodies that fit your desired properties. 
 Confidential Materials omitted and filed separately with the Securities and
Exchange Commission. A total of 4 pages were omitted. 

  
 D-2 

 EXHIBIT E 

JOINT PRESS RELEASE 

Joint Press Release has not been agreed at this time and is subject to mutual written agreement between authorized officers of both parties. 

  
 E-1 

 EXHIBIT F 

PERMITTED TARGET DESCRIPTIONS 

The following target descriptions may be used with no further description of the identity, nature or class of target: 

bacterial target 

  
 F-1 

 EXHIBIT G 

EXCERPT FROM ARSANIS ARTICLES 

[SEE ATTACHED PAGES.] 

  
 G-1 

	 Delaware  
	 PAGE 1 

The First State 
 I, JEFFREY W.
BULLOCK, SECRETARY OF STATE OF THE STATE OF DELAWARE, DO HEREBY CERTIFY THE ATTACHED IS A TRUE AND CORRECT COPY OF THE CERTIFICATE OF AMENDMENT OF “ARSANIS, INC.”, FILED IN THIS OFFICE ON THE FIFTEENTH DAY OF SEPTEMBER, A.D. 2010, AT 11:06
O’CLOCK A.M. 
 A FILED COPY OF THIS CERTIFICATE HAS BEEN FORWARDED TO THE NEW CASTLE COUNTY RECORDER OF DEEDS. 

 

					
	 4851982     8100
  

100909108
	 	 

	  	

	You may verify this certificate online at corp.delaware.gov/authver.shtml	 	  	 AUTHENTICATION: 8227827
  

DATE: 09-15-10

  
  
  

					
	 State of Delaware

Secretary of State

Division of Corporations

Delivered 11:14 AM 09/15/2010

FILED 11:06 AM 09/15/2010

SRV 100909108 - 4851982 FILE
	 		  	

 Arsanis, Inc. 

CERTIFICATE OF AMENDMENT 

OF 
 CERTIFICATE OF
INCORPORATION 
 Arsanis, Inc., a corporation organized and existing under the General Corporation Law of Delaware (the
“Corporation”) DOES HEREBY CERTIFY: 
  

	 	FIRST:	That the Board of Directors of the Corporation by unanimous written consent adopted resolutions proposing and declaring advisable that the Certificate of Incorporation of said corporation, filed with the Secretary of
State of Delaware, be amended as follows: 

  

	 	RESOLVED:	That the Board of Directors of this Corporation recommends and deems it advisable that the Certificate of Incorporation of this Corporation be amended by deleting Article FOURTH thereof and substituting for said Article
FOURTH the new Article FOURTH set forth on Exhibit A attached hereto; 

  

	 	RESOLVED:	That the aforesaid proposed amendment be submitted to the stockholders of this Corporation for their consideration. 

  

	 	RESOLVED:	That following the approval by the stockholders of the aforesaid amendment as required by law, the officers of this Corporation be, and they hereby are, and each of them hereby is, authorized and directed (i) to
prepare, execute and file with the Secretary of State of the State of Delaware a Certificate of Amendment setting forth the aforesaid amendment in the form approved by the stockholders and (ii) to take any and all other actions necessary,
desirable or convenient to give effect to the aforesaid amendment or otherwise to carry out the purposes of the foregoing resolutions. 

  

	 	SECOND:	That in lieu of a meeting and vote of stockholders, the stockholders have given written consent to said amendment in accordance with the provisions of Section 228 of the General Corporation Law of the State of
Delaware. 

  

	 	THIRD:	That the aforesaid amendments were duly adopted in accordance with the applicable provisions of Sections 242 of the General Corporation Law of the State of Delaware. 

 IN WITNESS WHEREOF, the Corporation has caused this Certificate of Amendment to be signed by
Robert L. Birnbaum, its Secretary, this 15th day of September, 2010. 
  

	
	 /s/ Robert L. Birnbaum

	 Robert L. Birnbaum

 Exhibit A 

Article Fourth of Certificate of Incorporation of Arsanis, Inc. 

FOURTH: The total number of shares of all classes of capital stock which the Corporation shall have authority to issue shall be
6,779,078 shares divided into two classes, as follows: 4,464,539 shares of common stock, par value $0.001 per share (the “Common Stock”) and 2,314,539 shares of Preferred Stock, par value $0.001 per share (the “Preferred Stock”).

 A description of the respective classes of stock and a statement of the designations, preferences, voting powers, relative,
participating, optional or other special rights and privileges and the qualifications, limitations and restrictions of the Preferred Stock and Common Stock are as follows: 

A. Common Stock. 
 1.
Relative Rights of Preferred Stock and Common Stock. All preferences, voting powers, relative, participating, optional or other special rights and privileges, and qualifications, limitations or restrictions, of the Common Stock are expressly
made subject and subordinate to those that may be fixed with respect to any shares of the Preferred Stock. 
 2. Voting Rights.
Except as otherwise required by law or this Certificate of Incorporation, the holders of Common Stock will be entitled to one vote per share on all matters to be voted on by the stockholders of the Corporation. 

3. Increase/Decrease of Common Stock. Notwithstanding the provisions of Section 242(b)(2) of the Delaware General Corporation Law,
the number of authorized shares of Common Stock may be increased or decreased (but not below the number of shares then outstanding) by (in addition to any vote of the holders of one or more series of Preferred Stock that may be required by the terms
of this Certificate of Incorporation) the affirmative vote of the holders of a majority of the outstanding shares of capital stock of the Corporation, voting as a single class, with each such share being entitled to such number of votes per share as
is provided in this Article FOURTH. 
 4. Dividends. Dividends may be paid on the Common Stock out of funds legally available
therefor it, as and when determined by the Board of Directors of the Corporation subject to the restrictions of Section B(2) below. 

5. Dissolution, Liquidation or Winding-Up. In the event of any dissolution, liquidation or winding-up of the affairs of the Corporation, after distribution in full of the preferential amounts, if any, to be distributed to the holders of shares of the Preferred Stock, holders of Common Stock shall be
entitled, unless otherwise provided by law or this Certificate of Incorporation, to receive all of the remaining assets of the Corporation of whatever kind available for distribution to stockholders ratably in proportion to the number of shares of
Common Stock held by them. 

 B. Preferred Stock. 

1. Designation. Of the class of 2,314,539 shares of Preferred Stock which the Corporation has the authority to issue: (i) 200,001 shares
shall be a series designated and known as “Series A-1 Convertible Preferred Stock” (“Series A-1 Preferred Stock”) and (ii) 2,114,538 shares shall be
a series designated and known as the “Series A-2 Convertible Preferred Stock” (“Series A-2 Preferred Stock”). 

2. Dividends. Dividends may be declared and paid on Preferred Stock from funds lawfully available therefor if, as and when, determined
by the Board of Directors of the Corporation; provided, that the holders of the Preferred Stock shall be entitled to receive, out of funds legally available therefor, dividends at the same rate and same time as dividends (other than dividends paid
in additional shares of Common Stock) are paid with respect to the Common Stock (treating each share of Preferred Stock as being equal to the number of shares of Common Stock (including fractions of a share) into which each share of Preferred Stock
is then convertible). 
 3. Liquidation, Dissolution or Winding-Up; Certain Mergers,
Consolidations and Asset Sales. 
 (a) Payment to Preferred Stock Upon Liquidation. 

(i) Preferred Stock. Upon any liquidation, dissolution or winding-up of the
Corporation, whether voluntary or involuntary, the holders of each share of Preferred Stock then outstanding shall be entitled to receive an amount, to be paid first out of the assets of the Corporation available for distribution to holders of the
capital stock of all classes, equal to the greater of the following: 
 (l) In the case of the Series A-1 Preferred Stock, $2.00 per share (which amount shall be subject to equitable adjustment whenever there shall occur a stock dividend, distribution, combination of shares, reclassification or other similar event
affecting such shares) plus all declared and unpaid dividends thereon to and including the date full payment shall be tendered to the holders of Preferred Stock with respect to such liquidation, dissolution or
winding-up; 
 (2) In the case of the Series
A-2 Preferred Stock, $4.54 per share (which amount shall be subject to equitable adjustment whenever there shall occur a stock dividend, distribution, combination of shares, reclassification or other similar
event affecting such shares) plus all declared and unpaid dividends thereon to and including the date full payment shall be tendered to the holders of Preferred Stock with respect to such liquidation, dissolution or
winding-up; or 
 (3) Such amount per share of Preferred Stock as would have been
payable had all shares of Preferred Stock been converted to Common Stock immediately prior to such event of liquidation, dissolution or winding-up pursuant to the provisions of Section 5. 

  
 4 

 If the assets of the Corporation shall be insufficient to permit the payment in full to the
holders of the Preferred Stock of all amounts distributable to them under subsection (a)(i), then the entire assets of the Corporation available for such distribution shall be distributed ratably among the holders of the Preferred Stock on a pari
passu basis in proportion to the full preferential amount each such holder is otherwise entitled to receive. 
 (ii)
Common Stock. After such payments shall have been made in full to the holders of the Preferred Stock or funds necessary for such payments shall have been set aside by the Corporation in trust for the account of holders of Preferred Stock so
as to be available for such payments, the remaining assets available for distribution shall be distributed among the holders of the Common Stock ratably in proportion to the number of shares of Common Stock held by them. 

Upon conversion of shares of Preferred Stock into shares of Common Stock pursuant to Section 5 below, the holder of such Common Stock
shall not be entitled to any preferential payment or distribution in case of any liquidation, dissolution or winding-up of the Corporation, but shall share ratably in any distribution of the assets of the
Corporation to all the holders of Common Stock. 
 (b) Distributions Other than Cash. Whenever the distribution provided for in this
Section 3 shall be payable in property other than cash, the value of such distribution shall be the fair market value of such property as determined in good faith by the Board of Directors of the Corporation. 

(c) Merger as Liquidation, etc. The holders of the Preferred Stock at the time of (i) a consolidation or merger of the Corporation into
or with any other entity or entities that results in the exchange of outstanding shares of the Corporation for securities or other consideration issued or paid or caused to be issued or paid by any such entity or affiliate thereof (except a
consolidation or merger in which the holders of the Corporation’s voting stock outstanding immediately prior to the transaction constitute a majority of the holders of voting stock of the surviving entity outstanding immediately following the
transaction), (ii) the sale or transfer by the Corporation of all or substantially all its assets in a single transaction or series of related transactions, (iii) the granting by the Corporation of an exclusive license in all fields with
respect to all or substantially all of the Corporation’s intellectual property in a single transaction or series of related transactions, or (iv) the sale or transfer by the Corporation’s stockholders of capital stock representing a
majority of the voting power at elections of directors of the Corporation (each, an “Event”), may deem such Event to be a liquidation within the meaning of the provisions of this Section 3 by a vote of at a majority of the then
outstanding shares of all series of Preferred Stock (voting as a single class on an as-converted to Common Stock basis) and by giving written notice thereof to the Corporation at least three days before the
effective date of the Event. Any cash, property, rights or securities distributed to such holders by the acquiring person, firm or other entity upon such Event shall be deemed to be applied toward, and all consideration received by the Corporation
in such asset sale together with all other available assets of the Corporation shall be distributed toward the liquidation payments attributable to the shares of Preferred Stock. The value of such property, rights or other securities shall be
determined in good faith by the Board of Directors of the Corporation. 

  
 5 

 (d) Notice and Opportunity to Exercise Conversion Rights. Notwithstanding anything to the
contrary that may be inferred from the provisions of this Section 3, each holder of shares of Preferred Stock shall be entitled to receive notice from the Corporation pursuant to Section 5(k) hereof of any proposed Event, liquidation,
dissolution or winding-up of the Corporation at least ten (10) days prior to the date on which any such Event, liquidation, dissolution or winding-up of the Corporation
is scheduled to occur and, at any time prior to any such Event, liquidation, dissolution or winding-up of the Corporation, to convert any or all of such holder’s shares of Preferred Stock into shares of
Common Stock pursuant to Section 5 hereof. 
 (e) Effecting an Event. 

(1) The Corporation shall not have the power to effect an Event unless the agreement or plan of merger or consolidation for such transaction
(the “Merger Agreement”) provides that the consideration payable to the stockholders of the Corporation shall be allocated among the holders of capital stock of the Corporation in accordance with Section 3 above. 

(2) In the event of an Event, if the Corporation does not effect a dissolution of the Corporation under the General Corporation Law of the
State of Delaeare within 30 days after such Deemed Liquidation Event, then (i) the Corporation shall send a written notice to each holder of Preferred Stock no later than the 30th day after Event advising such holders of their right (and the
requirements to be met to secure such right) pursuant to the terms of the following clause (ii) to require the redemption of such shares of Preferred Stock, and (ii) (x) the holders of at least a majority of the then-outstanding shares of
Series A-1 Preferred Stock and (y) the holders of at least a majority of the then-outstanding shares of Series A-2 Preferred Stock so request in a written
instrument delivered to the Corporation not later than 60 days after such Event, the Corporation shall use the consideration received by the Corporation for such Event (net of any retained liabilities associated with the assets sold or technology
licensed, as determined in good faith by the Board of Directors of the Corporation) (the “Net Proceeds”), to the extent legally available therefor, on the 90th day after such Event, to redeem, on a pari passu basis, all
(i) outstanding shares of Series A-1 Preferred Stock at a price per share equal to the greater of (x) $2.00 per share (which amount shall be subject to equitable adjustment whenever there shall occur a
stock dividend, distribution, combination of shares, reclassification or other similar event affecting such shares) plus all declared and unpaid dividends thereon and (y) such amount per share of Series
A-1 Preferred Stock as would have been payable had all shares of Series A-1 Preferred Stock been converted to Common Stock immediately prior to such Event and all such
Net Proceeds distributed in accordance with Section 3(a)(i)(3) and (ii) outstanding shares of Series A-2 Preferred Stock at a price per share equal to the greater of (x) $4.54 per share (which amount
shall be subject to equitable adjustment whenever there shall occur a stock dividend, distribution, combination of shares, reclassification or other similar event affecting such shares) plus all declared and unpaid dividends thereon and
(y) such amount per share of Series A-2 Preferred Stock as would have been payable had all shares of Series A-2 Preferred Stock been converted to Common Stock
immediately prior to such Event and all such Net Proceeds distributed in accordance with Section 3(a)(i)(3). Notwithstanding the foregoing, in the event of a redemption pursuant to the preceding sentence, if the Net Proceeds are not sufficient
to redeem all outstanding shares of 

  
 6 

 Preferred Stock, or if the Corporation does not have sufficient lawfully available funds to effect such
redemption, the Corporation shall redeem a pro rata portion of each holder’s shares of Preferred Stock to the fullest extent of such Net Proceeds or such lawfully available funds, as the case may be, based on the respective amounts which would
otherwise be payable in respect of the shares to be redeemed if the legally available funds were sufficient to redeem all such shares, and shall redeem the remaining shares to have been redeemed as soon as practicable after the Corporation has funds
legally available therefor. The provisions of Section 7 shall apply, with such necessary changes in the details thereof as are necessitated by the context, to the redemption of the Preferred Stock pursuant to this Section 3(e). Prior to
the distribution or redemption provided for in this Section 3(e), the Corporation shall not expend or dissipate the consideration received for such Event, except to discharge expenses incurred in connection with such Event or in the ordinary
course of business. 
 (ii) Amount Deemed Paid or Distributed. lf the amount deemed paid or distributed under this
Section 3(e) is made in property other than in cash, the value of such distribution shall be the fair market value of such property, determined as follows: 

(1) For securities not subject to investment letters or other similar restrictions on free marketability, 

(2) if traded on a securities exchange, unless otherwise specified in a Merger Agreement, the value shall be deemed to be the
average of the closing prices of the securities on such exchange or market over the 30-day period ending three days prior to the closing of such transaction; 

(3) if actively traded over-the-counter, unless
otherwise specified in a Merger Agreement, the value shall be deemed to be the average of the closing bid prices over the 30-day period ending three days prior to the closing of such transaction; or 

(4) if there is no active public market, the value shall be the fair market value thereof, as determined in good faith by the
Board of Directors of the Corporation (including a majority of the directors designated by holders of Preferred Stock). 

(5) The method of valuation of securities subject to investment letters or other similar restrictions on free marketability
(other than restrictions arising solely by virtue of a stockholder’s status as an affiliate or former affiliate) shall take into account an appropriate discount (as determined in good faith by the Board of Directors of the Corporation
(including a majority of the directors designated by holders of Preferred Stock)) from the market value as determined above so as to reflect the approximate fair market value thereof. 

(f) Allocation of Escrow or Contingent Payments. In the case of an Event, if any portion of the consideration payable to the
stockholders of the Corporation is placed into escrow and/or is payable to the stockholders of the Corporation subject to contingencies, the Merger Agreement shall provide that (a) the portion of such consideration that is not placed in 

  
 7 

 escrow and not subject to any contingencies (the “Initial Consideration”) shall be allocated among the
holders of capital stock of the Corporation in accordance with Section 3(a) above as if the Initial Consideration were the only consideration payable in connection with such Event and (b) any additional consideration which becomes payable
to the stockholders of the Corporation upon release from escrow or satisfaction of contingencies shall be allocated among the holders of capital stock of the Corporation in accordance with Section 3(e) above above after taking into account the
previous payment of the Initial Consideration as part of the same transaction. 
 4. Voting. 

(a) Each holder of outstanding shares of Preferred Stock shall be entitled to the number of votes equal to the number of whole shares of
Common Stock into which the shares of Preferred Stock held by such holder are then convertible (as adjusted from time to time pursuant to Section 5 hereof), at each meeting of stockholders of the Corporation (and written actions of stockholders
in lieu of meetings) with respect to any and all matters presented to the stockholders of the Corporation for their action or consideration. Except as provided by law or by the provisions establishing any other series of Preferred Stock, holders of
Preferred Stock shall vote together with the holders of Common Stock as a single class on all actions to be taken by the stockholders of the Corporation, including, but not limited to actions amending the Certificate of Incorporation of the
Corporation to increase the number of authorized shares of Common Stock. 
 (b) In addition to any other rights provided by law, for so long
as not less than twenty percent (20%) of the shares of Preferred Stock that have been issued remain outstanding (appropriately adjusted to take account of any stock split, stock dividend, combination of shares or the like), the Corporation shall
not, without first obtaining the affirmative vote or written consent of the holders of at least a majority of the then outstanding shares of Preferred Stock voting together as a single class on an as-converted
to Common Stock basis: 
 (i) amend, alter or repeal any provision of, or add any provision to, the Corporation’s
Certificate of Incorporation or By-laws, including amendment by or incident to a merger; 

(ii) incur any obligation to issue shares of, or authorize or designate any class or series of capital stock having any rights
senior to or on a parity with the Preferred Stock as to redemption, dividends, liquidation or otherwise; 
 (iii) amend,
alter or repeal the preferences, rights or privileges of the Preferred Stock including, without limitation the Series A-1 Preferred Stock and/or the Series A-2 Preferred
Stock; 
 (iv) pay or declare any dividend or distribution on any shares of its capital stock (except dividends payable
solely in shares of Common Stock), or apply any of its assets to the redemption, retirement, purchase or acquisition, directly or indirectly, through subsidiaries or otherwise, of any shares of its capital stock (other than repurchase of Common
Stock upon termination of employment or service pursuant to written agreements in effect on the date hereof or written agreements approved by the Corporation’s Board of Directors); 

  
 8 

 (v) voluntarily liquidate, dissolve or
wind-up or consent to any of the foregoing; 
 (vi) effect a change of control,
liquidation, merger, reincorporation, recapitalization, or sale or other transfer of a substantial part of the Corporation’s assets other than in the ordinary course of business, including without limitation an Event, or consent to the any of
the foregoing; 
 (vii) effect any acquisition of the capital stock of another entity which results in the consolidation of
that entity into the results of operations of the Corporation or acquisition of all or substantially all of the assets of another entity; 

(viii) incur indebtedness for borrowed funds, in a single or related series of transactions, in principal amount at any time
outstanding in excess of $500,000; 
 (ix) except as contemplated by Section 5(d)(i)(C)(IV), create a new plan or
arrangement for the grant of stock options, stock appreciation rights, restricted stock or other similar stock-based compensation, or increase the number of shares or other rights available under such existing plan or arrangement; or 

(x) form a subsidiary, or acquire any equity interest in any other entity, other than a wholly-owned subsidiary, the
composition of who’s board of directors, managers or other similar governing body is identical to the composition of the Board of Directors of the Corporation. 

5. Optional Conversion. The holders of the Preferred Stock shall have conversion rights as follows (the “Conversion Rights”):

 (a) Right to Convert. Each share of Preferred Stock shall be convertible, at the option of the holder thereof, at any time and
from time to time, and without the payment of additional consideration by the holder threreof, into such number of fully paid and nonassessable shares of Common Stock as is determined by dividing $2.00 (in the case of the Series A-1 Preferred Stock) or $4.54 (in the case of the Series A-2 Preferred Stock) by the Conversion Price (as defined below) in effect at the time of conversion. The “Series A-1 Conversion Price” shall initially be $2.00 and the “Series A-2 Conversion Price” shall initially be $4.54. The Series
A-1 Conversion Price and the Series A-2 Conversion Price shall collectivelly be referred to herein as the “Conversion Prices”. Such initial Conversion Prices,
and the rate at which shares of Series A-1 Preferred Stock and Series A-2 Preferred Stock may be converted into shares of Common Stock, shall be subject to adjustment as provided below. 

(b) Fractional Shares. No fractional shares of Common Stock shall be issued upon conversion of the Preferred Stock. In lieu of any
fractional shares to which the holder would otherwise be entitled, the Corporation shall pay cash equal to such fraction multiplied by the then effective applicable Conversion Price. Whether or not fractional shares would be issuable upon such
conversion shall be determined on the basis of the total number of shares of Preferred Stock the holder is at the time converting into Common Stock and the aggregate number of shares of Common Stock issueable upon such conversion. 

  
 9 

 (c) Mechanics of Conversion. 

(i) In order for a holder of Preferred Stock to convert shares of Preferred Stock into shares of Common Stock, such holder
shall surrender the certificate or certificates for such shares of Preferred Stock (or, if such holder alleges that such certificate has been lost, stolen or destroyed, a lost certificate affidavit and agreement reasonably acceptable to the
Corporation to indemnify the Corporation against any claim that may be made against the Corporation on account of the alleged loss, theft or destruction of such certificate), at the office of the transfer agent for the Preferred Stock (or at the
principal office of the Corporation if the Corporation serves as its own transfer agent), together with written notice that such holder elects to convert all or any number of the shares of Preferred Stock represented by such certificate or
certificates. If required by the Corporation, certificates surrendered for conversion shall be endorsed or accompanied by a written instrument or instruments of transfer, in form satisfactory to the Corporation, duly executed by the registered
holder or his, her or its attorney duly authorized in writing. The date of receipt of such certificates (or lost certificate affidavit and agreement) and notice by the transfer agent (or by the Corporation if the Corporation serves as its own
transfer agent) shall be the conversion date (“Conversion Date”), and the shares of Common Stock issuable upon conversion of the shares represented by such certificate shall be deemed to be outstanding of record as of such date. The
Corporation shall, as soon as practicable after the Conversion Date, issue and deliver at such office to such holder of Preferred Stock a certificate or certificates for the number of shares of Common Stock to which such holder shall be entitled,
together with cash in lieu of any fraction of a share. 
 (ii) The Corporation shall at all times when any Preferred Stock
shall be outstanding, reserve and keep available out of its authorized but unissued stock, for the purpose of effecting the conversion of the Preferred Stock, such number of its duly authorized shares of Common Stock as shall from time to time be
sufficient to effect the conversion of all outstanding Preferred Stock. Before taking any action which would cause an adjustment reducing either of the Conversion Prices below the then par value of the shares of Common Stock issuable upon conversion
of the Preferred Stock, the Corporation will take any corporate action which may, in the opinion of its counsel, be necessary in order that the Corporation may validly and legally issue fully paid and nonassessable shares of Common Stock at such
adjusted Conversion Prices. 
 (iii) Upon any such conversion, no adjustment to the Conversion Prices shall be made for any
declared but unpaid dividends on the Preferred Stock surrendered for conversion or on the Common Stock delivered upon conversion. 

(iv) All shares of Preferred Stock which shall have been surrendered for conversion as herein provided shall no longer be
deemed to be outstanding and all rights with respect to such shares, including the rights, if any, to receive notices and to vote such shares of Preferred Stock, shall immediately cease and terminate on the Conversion Date, except only the right of
the holders thereof to receive shares of Common Stock in exchange therefor and payment of any dividends declared but unpaid thereon. Any shares of Preferred Stock so converted shall be retired and cancelled and 

  
 10 

 
shall not be reissued, and the Corporation (without the need for stockholder action) may from time to time take such appropriate action as may be necessary to reduce the authorized number of
shares of Preferred Stock and the number of shares of Series A-1 Preferred Stock and/or Series A-2 Preferred Stock, accordingly. 

(v) The Corporation shall pay any and all issue and other taxes that may be payable in respect of any issuance or delivery of
shares of Common Stock upon conversion of shares of Preferred Stock pursuant to this Section 5. The Corporation shall not, however, be required to pay any tax which may be payable in respect of any transfer involved in the issuance and delivery
of shares of Common Stock in a name other than that in which the shares of Preferred Stock so converted were registered, and no such issuance or delivery shall be made unless and until the person or entity requesting such issuance has paid to the
Corporation the amount of any such tax or has established, to the satisfaction of the Corporation, that such tax has been paid. 
 (d)
Adjustments to Conversion Price for Diluting Issues: 
 (i) Special Definitions. For purposes of this
Section 5, the following definitions shall apply: 
 (A) “Option” shall mean rights, options or
warrants to subscribe for, purchase or otherwise acquire Common Stock or Convertible Securities. 
 (B) “Convertible
Securities” shall mean any evidences of indebtedness, shares or other securities directly or indirectly convertible into or exchangeable for Common Stock, but excluding Options. 

(C) “Additional Shares of Common Stock” shall mean all shares of Common Stock issued (or, pursuant to
Subsection 5(d)(iii) below, deemed to be issued) by the Corporation after the date hereof other than: 
  

	 	(I)	shares of Common Stock issued or issuable upon conversion of shares of Preferred Stock; 

  

	 	(II)	shares of Common Stock issued or issuable as a dividend or distribution on Preferred Stock; 

  

	 	(III)	shares of Common Stock issued or issuable by reason of a dividend, stock split, split-up or other distribution on shares of Common Stock that is covered by Subsection 5(e) or 5(f)
below; 

  

	 	(IV)	up to 1,683,333 shares (appropriately adjusted to take account of any stock split, stock dividend, combination of shares or the like) of Common Stock (or Options with respect thereto) issued or issuable to employees or
directors of, or consultants 

  
 11 

	 	
to, the Corporation pursuant to a plan or arrangement in effect prior to the issuance of any Preferred Stock or a plan or arrangement approved by the Board of Directors of the Corporation or any
combination of such plans; or 

  

	 	(V)	shares of Common Stock (including Options or Convertible Securities) (a) issued solely in consideration for the acquisition (whether by merger or otherwise) by the Corporation of all or substantially all of the
capital stock or assets of any other corporation or entity, or (b) issued in connection with an equipment financing, line of credit or other lending arrangement; provided, however, the issuance of such shares pursuant to
(a) or (b) above is approved by holders of at least a majority of the then outstanding shares of Preferred Stock voting together as a single class on an as-converted to Common Stock basis.

 (ii) No Adjustment of Conversion Prices. No adjustment in the number of shares of Common Stock into
which Series A-1 Preferred Stock is convertible shall be made, by adjustment in the Series A-1 Conversion Price unless the consideration per share (determined pursuant
to Subsection 5(d)(v)) for an Additional Share of Common Stock issued or deemed to be issued by the Corporation is less than the Series A-1 Conversion Price in effect immediately prior to the issue of such
Additional Shares of Common Stock. No adjustment in the number of shares of Common Stock into which Series A-2 Preferred Stock is convertible shall be made, by adjustment in the Series A-2 Conversion Price unless the consideration per share (determined pursuant to Subsection 5(d)(v)) for an Additional Share of Common Stock issued or deemed to be issued by the Corporation is less than the Series A-2 Conversion Price in effect immediately prior to the issue of such Additional Shares of Common Stock. Further no adjustment shall be made to either of the Conversion Prices, if prior to, or after, such issuance,
the Corporation receives written notice from the holders of at least a majority of the then outstanding shares of Preferred Stock voting together as a single class on an as-converted to Common Stock basis
agreeing that no such adjustment shall be made as the result of the issuance of Additional Shares of Common Stock. 
 (iii)
Issue of Securities Deemed Issue of Additional Shares of Common Stock. If the Corporation at any time or from time to time hereafter shall issue any Options or Convertible Securities (excluding Options or Convertible Securities covered by
Subsection 5(d)(i)(C)(IV) and (V) above) or shall fix a record date for the determination of holders of any class of securities entitled to receive any such Options or Convertible Securities, then the maximum number of shares of Common Stock
(as set forth in the instrument relating thereto without regard to any provision contained therein for a subsequent adjustment of such number) issuable upon the exercise of such Options or, in the case of Convertible Securities and Options therefor,
the conversion or exchange 

  
 12 

 of such Convertible Securities, shall be deemed to be Additional Shares of Common Stock issued as
of the time of such issue or, in case such a record date shall have been fixed, as of the close of business on such record date, provided that Additional Shares of Common Stock shall not be deemed to have been issued unless the consideration per
share (determined pursuant to Subsection 5(d)(v) hereof) of such Additional Shares of Common Stock would be less than the Series A-1 Conversion Price or Series A-2
Conversion Price, as applicable, in effect on the date of and immediately prior to such issue, or such record date, as the case may be, and provided further that in any such case in which Additional Shares of Common Stock are deemed to be issued:

 (A) No further adjustment in either of the Conversion Prices shall be made upon the subsequent issue of Convertible
Securities or shares of Common Stock upon the exercise of such Options or conversion or exchange of such Convertible Securities; 

(B) If such Options or Convertible Securities by their terms provide, with the passage of time or otherwise, for any increase
or decrease in the consideration payable to the Corporation, then upon the exercise, conversion or exchange thereof, the Conversion Prices computed upon the original issue thereof (or upon the occurrence of a record date with respect thereto), and
any subsequent adjustments based thereon, shall, upon any such increase or decrease becoming effective, be recomputed to reflect such increase or decrease insofar as it affects such Options or the rights of conversion or exchange under such
Convertible Securities; 
 (C) Upon the termination of any Option or any right to convert or exchange any Convertible
Securities as to which an adjustment in either of the Conversion Price pursuant to Section 5(d)(iv) has previously been made upon the grant or issuance thereof, the Conversion Price(s) then in effect hereunder shall forthwith be increased to
the Conversion Price(s) which would have been in effect at the time of such termination had such Option or Convertible Securities, to the extent outstanding immediately prior to such termination, never been issued; 

(D) In the event of any change in the number of shares of Common Stock issuable upon the exercise, conversion or exchange of
any such Option or Convertible Security, including, but not limited to, a change resulting from the anti-dilution provisions thereof, the Conversion Price(s) then in effect shall forthwith be readjusted to such Conversion Price(s) as would have
obtained had the adjustment which was made upon the issuance of such Option or Convertible Security not exercised, converted or exchanged prior to such change been made upon the basis of such change; and 

(E) No readjustment pursuant to clause (B), (C) or (D) above shall have the effect of increasing either of the Conversion
Prices to an amount which exceeds the lower of (i) the Conversion Price(s) immediately preceding adjustment on the original adjustment date, or (ii) the Conversion Price(s) that would have resulted from any issuances of Additional Shares
of Common Stock between the original adjustment date and such readjustment date. 

  
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 In the event the Corporation amends the terms of any such Options or Convertible Securities so as
to change the number of securities for which they are exercisable, convertible or exchangeable or the consideration payable thereunder, then such Options or Convertible Securities, as so amended, shall be deemed to have been issued after the date
hereof and the provisions of this Subsection 5(d)(iii) shall apply. 
 (iv) Adjustment of Conversion Prices Upon Issuance
of Additional Shares of Common Stock. In the event the Corporation shall at any time hereafter issue Additional Shares of Common Stock (including Additional Shares of Common Stock deemed to be issued pursuant to Subsection 5(d)(iii)), without
consideration or for a consideration per share less than the applicable Conversion Prices in effect immediately prior to such issue, then and in such event, the applicable Conversion Prices shall be reduced, concurrently with such issue, to a price
(calculated to the nearest cent) determined by multiplying such applicable Conversion Price by a fraction, (A) the numerator of which shall be (1) the number of shares of Common Stock outstanding immediately prior to such issue plus
(2) the number of shares of Common Stock which the aggregate consideration received or to be received by the Corporation for the total number of Additional Shares of Common Stock so issued would purchase at such applicable Conversion Price; and
(B) the denominator of which shall be the number of shares of Common Stock outstanding immediately prior to such issue plus the number of such Additional Shares of Common Stock so issued; provided that, (i) for the purpose of
this Subsection 5(d)(iv), all shares of Common Stock issuable upon conversion or exchange of Convertible Securities or Options outstanding immediately prior to such issue shall be deemed to be outstanding, and (ii) the number of shares of
Common Stock deemed issuable upon conversion or exchange of such outstanding Convertible Securities shall not give effect to any adjustments to the conversion or exchange price or conversion or exchange rate of such Convertible Securities resulting
from the issuance of Additional Shares of Common Stock that is the subject of this calculation. 
 (v) Determination of
Consideration. For purposes of this Subsection 5( d), the consideration received by the Corporation for the issue of any Additional Shares of Common Stock shall be computed as follows: 

(A) Cash and Property: Such consideration shall: 

 

	 	(I)	insofar as it consists of cash, be computed at the aggregate of cash received by the Corporation, excluding amounts paid or payable for accrued interest; 

 

	 	(II)	insofar as it consists of property other than cash, be computed at the fair market value thereof at the time of such issue, as determined in good faith by the Board of Directors; and 

  
 14 

	 	(III)	in the event Additional Shares of Common Stock are issued together with other shares or securities or other assets of the Corporation for consideration which covers both, be the proportion of such consideration so
received, computed as provided in clauses (I) and (II) above, as determined in good faith by the Board of Directors. 

(B) Options and Convertible Securities. The consideration per share received by the Corporation for Additional Shares of
Common Stock deemed to have been issued pursuant to Subsection 5(d)(iii), relating to Options and Convertible Securities, shall be determined by dividing 

(x) the total amount, if any, received or receivable by the Corporation as consideration for the issue of such Options or
Convertible Securities, plus the minimum aggregate amount of additional consideration (as set forth in the instruments relating thereto, without regard to any provision contained therein for a subsequent adjustment of such consideration) payable to
the Corporation upon the exercise of such Options or the conversion or exchange of such Convertible Securities, or in the case of Options for Convertible Securities, the exercise of such Options for Convertible Securities and the conversion or
exchange of such Convertible Securities, by 
 (y) the maximum number of shares of Common Stock (as set forth in the
instruments relating thereto, without regard to any provision contained therein for a subsequent adjustment of such number) issuable upon the exercise of such Options or the conversion or exchange of such Convertible Securities. 

(vi) Multiple Closing Dates. In the event the Corporation shall issue on more than one date Additional Shares of Common Stock which are
comprised of shares of the same series of Preferred Stock, and such issuance dates occur within a period of no more than 120 days, then, upon the final such issuance, the applicable Conversion Prices shall be adjusted to give effect to all such
issuances as if they occurred on the date of the final such issuance (and without giving effect to any adjustments as a result of such prior issuances within such period). 

(e) Adjustment for Stock Splits and Combinations. If the Corporation shall at any time or from time to time after the date hereof
effect a subdivision of the outstanding Common Stock, the Conversion Prices then in effect immediately before that subdivision shall be proportionately decreased. If the Corporation shall at any time or from time to time after the date hereof
combine the outstanding shares of Common Stock, the Conversion Prices then in effect immediately before the combination shall be proportionately increased. Any adjustment under this paragraph shall become effective at the close of business on the
date the subdivision or combination becomes effective. 

  
 15 

 (f) Adjustment for Certain Dividends and Distributions. In the event the Corporation at
any time, or from time to time after the date hereof shall make or issue, or fix a record date for the determination of holders of Common Stock entitled to receive, a dividend or other distribution payable in additional shares of Common Stock, then
and in each such event each Conversion Price then in effect immediately before such event shall be decreased as of the time of such issuance or, in the event such a record date shall have been fixed, as of the close of business on such record date,
by multiplying the applicable Conversion Price then in effect by a fraction: 
 (1) the numerator of which shall be the total
number of shares of Common Stock issued and outstanding immediately prior to the time of such issuance or the close of business on such record date, and 

(2) the denominator of which shall be the total number of shares of Common Stock issued and outstanding immediately prior to
the time of such issuance or the close of business on such record date plus the number of shares of Common Stock issuable in payment of such dividend or distribution; 

provided, however, if such record date shall have been fixed and such dividend is not fully paid or if such distribution is not fully made on the date fixed
therefor, the Conversion Prices shall be recomputed accordingly as of the close of business on such record date and thereafter the Conversion Prices shall be adjusted pursuant to this paragraph as of the time of actual payment of such dividends or
distributions; and provided further, however, that no such adjustment shall be made if the holders of Preferred Stock simultaneously receive (i) a dividend or other distribution of shares of Common Stock in a number equal to the number of
shares of Common Stock as they would have received if all outstanding shares of Preferred Stock had been converted into Common Stock on the date of such event or (ii) a dividend or other distribution of shares of Preferred Stock which are
convertible, as of the date of such event, into such number of shares of Common Stock as is equal to the number of additional shares of Common Stock being issued with respect to each share of Common Stock in such dividend or distribution. 

(g) Adjustments for Other Dividends and Distributions. In the event the Corporation at any time or from time to time after the date
hereof shall make or issue, or fix a record date for the determination of holders of Common Stock entitled to receive, a dividend or other distribution payable in securities of the Corporation (other than shares of Common Stock) or in cash or other
property (other than cash out of earnings or earned surplus, determined in accordance with generally accepted accounting principles), then and in each such event provision shall be made so that the holders of the Preferred Stock shall receive upon
conversion thereof in addition to the number of shares of Common Stock receivable thereupon, the amount of securities of the Corporation that they would have received had the Preferred Stock been converted into Common Stock on the date of such event
and had they thereafter, during the period from the date of such event to and including the conversion date, retained such securities receivable by them as aforesaid during such period, giving application to all adjustments called for during such
period under this paragraph with respect to the rights of the holders of the Preferred Stock; and provided further, however, that no such adjustment shall be made if the holders of Preferred Stock simultaneously receive a dividend or other
distribution of such securities in an amount equal to the amount of such securities as they would have received if all outstanding shares of Preferred Stock had been converted into Common Stock on the date of such event. 

  
 16 

 (h) Adjustment for Merger or Reorganization, etc. Subject to the provisions of Subsection
3(c), if there shall occur any reorganization, recapitalization, consolidation or merger involving the Corporation in which the Common Stock is converted into or exchanged for securities, cash or other property (other than a transaction covered by
paragraphs (e), (f) or (g) of this Section 5), then, following any such reorganization, recapitalization, consolidation or merger, each share of each series of Preferred Stock shall be convertible into the kind and amount of securities,
cash or other property which a holder of the number of shares of Common Stock of the Corporation issuable upon conversion of one share of such series of Preferred Stock immediately prior to such reorganization, recapitalization, consolidation or
merger would have been entitled to receive pursuant to such transaction; and, in such case, appropriate adjustment (as determined in good faith by the Board of Directors) shall be made in the application of the provisions in this Section 5 set
forth with respect to the rights and interest thereafter of the holders of the Preferred Stock, to the end that the provisions set forth in this Section 5 (including provisions with respect to changes in and other adjustments of the Conversion
Prices) shall thereafter be applicable, as nearly as reasonably may be, in relation to any shares of stock or other property thereafter deliverable upon the conversion of the Preferred Stock. 

(i) No Impairment. Unless approved by a majority of the then outstanding shares of Preferred Stock voting together as a single class on
an as-converted to Common Stock basis as provided in Section 4(b) above, the Corporation will not, by amendment of its Certificate of Incorporation or through any reorganization, transfer of assets,
consolidation, merger, dissolution, issue or sale of securities or any other voluntary action, avoid or seek to avoid the observance or performance of any of the terms to be observed or performed hereunder by the Corporation, but will at all times
in good faith assist in the carrying out of all the provisions of this Section 5 and in the taking of all such action as may be necessary or appropriate in order to protect the Conversion Rights of the holders of the Preferred Stock against
impairment. 
 (j) Certificate as to Adjustments. Upon the occurrence of each adjustment or readjustment of either of the Conversion
Prices pursuant to this Section 5, the Corporation at its expense shall promptly compute such adjustment or readjustment in accordance with the terms hereof and furnish to each holder of any applicable series of Preferred Stock a certificate
setting forth such adjustment or readjustment and showing in detail the facts upon which such adjustment or readjustment is based. The Corporation shall, upon the written request at any time of any holder of Preferred Stock, furnish or cause to be
furnished to such holder a certificate setting forth (i) the Conversion Prices then in effect, and (ii) the number of shares of Common Stock and the amount, if any, of other securities, cash or property which then would be received upon
the conversion of each such series of Preferred Stock. 
 (k) Notice of Record Date. In the event: 

(i) the Corporation shall take a record of the holders of its Common Stock (or other stock or securities at the time issuable
upon conversion of the Preferred Stock) for the purpose of entitling or enabling them to receive any dividend or other distribution, or to receive any right to subscribe for or purchase any shares of stock of any class or any other securities, or to
receive any other right; or 

  
 17 

 (ii) of any capital reorganization of the Corporation, any reclassification of
the Common Stock of the Corporation, any consolidation or merger of the Corporation with or into another corporation (other than a consolidation or merger in which the Corporation is the surviving entity and its Common Stock is not converted into or
exchanged for any other securities or property), or any transfer of all or substantially all of the assets of the Corporation; or 

(iii) of the voluntary or involuntary dissolution, liquidation or winding-up of the
Corporation or any Event, 
 then, and in each such case, the Corporation will mail or cause to be mailed to the holders of the Preferred Stock a notice
specifying, as the case may be, (i) the record date for such dividend, distribution or right, and the amount and character of such dividend, distribution or right, or (ii) the effective date on which such reorganization, reclassification,
consolidation, merger, transfer, dissolution, liquidation, winding-up or Event is to take place, and the time, if any is to be fixed, as of which the holders of record of Common Stock (or such other stock or
securities at the time issuable upon the conversion of the Preferred Stock) shall be entitled to exchange their shares of Common Stock (or such other stock or securities) for securities or other property deliverable upon such reorganization,
reclassification, consolidation, merger, transfer, dissolution, liquidation or winding-up. Such notice shall be mailed at least 10 days prior to the record date or effective date for the event specified in
such notice. 
 6. Mandatory Conversion. 

(a) Upon the closing of the sale of shares of Common Stock in an underwritten firm commitment public offering pursuant to an effective
registration statement under the Securities Act of 1933, as amended, in which (i) the price to the public per share is at least $22.70 (subject to equitable adjustment for any stock dividend, stock split, stock
split-up, combination of shares or the like) and (ii) the aggregate offering price is at least $50,000,000 (based on the market price or fair value at the time of such offering) (the “IPO Mandatory
Conversion Date”), (i) all outstanding shares of Series A-1 Preferred Stock shall automatically be converted into shares of Common Stock, at the then effective applicable conversion rate for Series A-1 Preferred Stock, (ii) all outstanding shares of Series A-2 Preferred Stock shall automatically be converted into shares of Common Stock, at the then effective
applicable conversion rate for Series A-2 Preferred Stock and (iii) all provisions included under the caption “Preferred Stock”, and all references to the Preferred Stock, shall be deleted and
shall be of no further force or effect. 
 (b) All outstanding shares of Series A-1 Preferred Stock
shall automatically be converted into shares of Common Stock, at the then effective applicable conversion rate for Series A-1 Preferred Stock and all outstanding shares of Series
A-2 Preferred Stock shall automatically be converted into shares of Common Stock, at the then effective applicable conversion rate for Series A-2 Preferred Stock upon
the conversion of more than 75% in voting power of the aggregate number of shares of Preferred Stock at any time issued by the 

  
 18 

 
Corporation (other than any shares of Preferred Stock that have been redeemed or, if a Redemption Election has been made pursuant to Section 7 below, that the Corporation is required to
redeem pursuant to such Section 7). Such conversion shall be deemed to have occurred on the date (the “Special Conversion Date” and collectively with the IPO Mandatory Conversion Date, “Mandatory Conversion Dates”) upon
which the aggregate number of shares of Preferred Stock which have been converted to Common Stock exceeds such 75%. 
 (c) All holders of
record of shares of Preferred Stock shall be given written notice of the relevant Mandatory Conversion Date and the place designated for mandatory conversion of all such Preferred Stock pursuant to this Section 6. Such notice need not be given
in advance of the occurrence of the Mandatory Conversion Date. Such notice shall be sent by first class or registered mail, postage prepaid, to each record holder of Preferred Stock at such holder’s address last shown on the records of the
transfer agent for the Preferred Stock (or the records of the Corporation, if it serves as its own transfer agent). Upon receipt of such notice, each holder of shares of Preferred Stock shall surrender his, her or its certificate or certificates for
all such shares (or, if such holder alleges that such certificate has been lost, stolen or destroyed, a lost certificate affidavit and agreement reasonably acceptable to the Corporation to indemnify the Corporation against any claim that may be made
against the Corporation on account of the alleged loss, theft or destruction of such certificate) to the Corporation at the place designated in such notice, and shall thereafter receive certificates for the number of shares of Common Stock to which
such holder is entitled pursuant to this Section 6. On the Mandatory Conversion Date, all outstanding shares of Preferred Stock shall be deemed to have been converted into shares of Common Stock, which shall be deemed to be outstanding of
record, and all rights with respect to the Preferred Stock so converted, including the rights, if any, to receive notices and vote (other than as a holder of Common Stock) will terminate, except for the rights of the holders thereof, upon surrender
of their certificate or certificates (or lost certificate affidavit and agreement) therefor, to receive certificates for the number of shares of Common Stock into which such Preferred Stock has been converted, and payment of any declared but unpaid
dividends thereon. If so required by the Corporation, certificates surrendered for conversion shall be endorsed or accompanied by a written instrument or instruments of transfer, in form satisfactory to the Corporation, duly executed by the
registered holder or by his, her or its attorney duly authorized in writing. As soon as practicable after the Mandatory Conversion Date and the surrender of the certificate or certificates for such Preferred Stock (or lost certificate affidavit and
agreement), the Corporation shall cause to be issued and delivered to such holder, or on his, her or its written order, a certificate or certificates for the number of full shares of Common Stock issuable on such conversion in accordance with the
provisions hereof and cash as provided in Subsection 5(b) in respect of any fraction of a share of Common Stock otherwise issuable upon such conversion. 

(d) All certificates evidencing shares of Preferred Stock which are required to be surrendered for conversion in accordance with the
provisions hereof shall, from and after the Mandatory Conversion Date, be deemed to have been retired and cancelled and the shares of Preferred Stock represented thereby converted into Common Stock for all purposes, notwithstanding the failure of
the holder or holders thereof to surrender such certificates on or prior to such date. Such converted Preferred Stock may not be reissued, and the Corporation may thereafter take such appropriate action (without the need for stockholder action) as
may be necessary to reduce the authorized number of shares of Preferred Stock accordingly. 

  
 19 

 7. Redemption. 

(a) At the written election of holders of at least a majority of the outstanding shares of Preferred Stock voting together as a single class
on an as-converted to Common Stock basis made at any time on or after the fifth anniversary of the first date of issuance of a share of Preferred Stock (the “Redemption Election”), the Corporation
shall be required to redeem all, but not less than all, of the outstanding shares of Preferred Stock in three equal annual installments, upon the terms set forth in this Section 7. The first installment of such redemption (the “First
Redemption Date”) shall occur on the date specified in the Redemption Election, which shall be not less than ninety days after the date of the Redemption Election, and the second and third installments of such redemption shall occur on the
first and second anniversaries, respectively, of the First Redemption Date. The Corporation shall redeem one-third of the outstanding shares of Preferred Stock held by each holder on the First Redemption Date,
one half of the outstanding shares of Preferred Stock held by each holder on the first anniversary thereof and the remaining shares on the second anniversary thereof. On each such redemption date, the holders shall surrender the certificate or
certificates for the shares to be redeemed (or, if such registered holder alleges that such certificate has been lost, stolen or destroyed, a lost certificate affidavit and agreement reasonably acceptable to the Corporation to indemnify the
Corporation against any claim that may be made against the Corporation on account of the alleged loss, theft or destruction of such certificate), duly endorsed for transfer or with duly executed stock transfer powers sufficient to permit transfer
attached, at the offices of the Corporation or of any transfer agent for the Preferred Stock. The Corporation shall, as soon as practicable thereafter, issue and deliver to each holder a certificate or certificates for the balance of the shares not
being redeemed. The redemption price per share of Preferred Stock shall be equal to $2.00 (in the case of the Series A-1 Preferred Stock) or $4.54 (in the case of the Series
A-2 Preferred Stock), in each case subject to equitable adjustment for any stock dividend, stock split, stock split-up, combination of shares or the like, plus all
dividends declared but unpaid on such share on the redemption date. 
 (b) Notice of redemption shall be sent by first class mail, postage
prepaid, to each holder of record of the Preferred Stock, not less than thirty days nor more than sixty days prior to the First Redemption Date, at the address of such holder as it appears on the books of the Corporation. Such notice shall set forth
(i) the First Redemption Date, the dates of the second and third installments of such redemption, and the place of redemption; and (ii) the number of shares to be redeemed on each date of redemption and the redemption price on each such
date. The Corporation shall be obligated to redeem the Preferred Stock on the dates and in the amounts set forth in the notice; provided, however, that any holder of Preferred Stock who is not party to a Redemption Election may convert any or all of
the shares owned by such holder into Common Stock in accordance with Section 5 at any time prior to the First Redemption Date. The Corporation, if advised before the First Redemption Date by written notice from any holder of record of Preferred
Stock to be redeemed who is not a party to a Redemption Election, shall credit against the number of shares of Preferred Stock required to be redeemed from such holder, and shall not redeem, the number of shares of Preferred Stock which had been
converted by such holder on or before such date and which had not previously been credited against any redemption. 

  
 20 

 (c) If, on or before a redemption date, the funds necessary for such redemption shall have been
set aside by the Corporation and deposited with a bank or trust company, in trust for the pro rata benefit of the holders of the Preferred Stock that has been called for redemption, then, notwithstanding that any certificates for shares that have
been called for redemption shall not have been surrendered for cancellation, the shares represented thereby shall no longer be deemed outstanding from and after such redemption date, and all rights of holders of such shares so called for redemption
shall forthwith, after such redemption date, cease and terminate with respect to such shares, excepting only the right to receive the redemption funds therefor to which they are entitled. Any interest accrued on funds so deposited and unclaimed by
stockholders entitled thereto shall be paid to such stockholders at the time their respective shares are redeemed or to the Corporation at the time unclaimed amounts are paid to it. In case the holders of Preferred Stock which shall have been called
for redemption shall not, within six years after the final redemption date, claim the amounts so deposited with respect to the redemption thereof, any such bank or trust company shall, upon demand, pay over to the Corporation such unclaimed amounts
and thereupon such bank or trust company shall be relieved of all responsibility in respect thereof to such holder and such holder shall look only to the Corporation for the payment thereof. Any funds so deposited with a bank or trust company which
shall not be required for such redemption by reason of the exercise subsequent to the date of such deposit of the right of conversion of any shares or otherwise shall be returned to the Corporation forthwith. 

(d) If the Corporation for any reason fails to redeem any of the shares of Preferred Stock in accordance with Section 7(a) on or prior to
the redemption dates determined in accordance with this Section 7, then, the Corporation shall become obligated to pay, in addition to the redemption price specified in Section 7(a), interest on the unpaid balance of such price, which
shall accrue at a rate of one percent (1%) per month until such price is paid in full. (For the purposes of this Section 7(d), shares of Preferred Stock for which funds have been set aside and deposited as provided in Section 7(c) shall be
deemed to be redeemed.) 
 (e) If the funds of the Corporation legally available for redemption of shares of Preferred Stock on a redemption
date are insufficient to redeem the total number of shares of Preferred Stock submitted for redemption, those funds which are legally available will be used to redeem the maximum possible number of whole shares ratably among the holders of such
shares. The shares of Preferred Stock not redeemed shall remain outstanding and entitled to all rights and preferences provided herein. At any time thereafter when additional funds of the Corporation are legally available for the redemption of such
shares of Preferred Stock, such funds will be used, at the end of the next succeeding fiscal quarter, to redeem the balance of such shares, or such portion thereof for which funds are then legally available. 

8. Waiver. Any of the rights of the holders of Preferred Stock set forth herein may be waived by the affirmative vote of the holders of
at least majority of the shares of Preferred Stock then outstanding voting together as a single class on an as-converted to Common Stock basis. 

  
 21 

 AMENDMENT NUMBER ONE 

TO THE 
 COLLABORATION
AGREEMENT 
 THIS AMENDMENT NUMBER ONE (the
“Amendment”) dated February 11, 2013 (the “Amendment Effective Date”) amends the COLLABORATION AGREEMENT (the “Agreement”) dated as of
May 1, 2011 (the “Original Effective Date”), by and between ADIMAB, LLC, a Delaware limited liability company having an address at 7 Lucent Drive, Lebanon, NH 03766
(“Adimab”) and ARSANIS, INC., a Delaware corporation having an address at 7 Lucent Drive, Lebanon, NH 03766 (together with Arsanis Biosciences GmbH, an
Austrian entity having an address at Helmut-Qualtinger-Gasse 2, Vienna, A-1030, Austria, collectively “Arsanis”) Capitalized terms used herein and not otherwise defined shall have the meanings ascribed to such words in the
Agreement. 
 BACKGROUND 

1. The Parties wish to extend the Target Nomination Period for [**] additional years. 

2. The Parties wish to explicitly acknowledge that Research Plans may include optimization of antibodies discovered by Arsanis or Third
Parties, and that the Parties wish to provide for different economics with respect to such optimized antibodies. 
 NOW,
THEREFORE, in consideration of the foregoing premises and the mutual covenants set forth below, and for other good and valuable consideration, the receipt of which is hereby acknowledged. Adimab and Arsanis hereby
agree as follows: 
  

	1.	Section 1.30 of the Agreement is hereby deleted in its entirety and replaced with the following language: 

“FTE Rate” means [**] dollars ($[**]) per FTE (or [**] dollars ($[**]) on a quarterly basis). 

The FTE Rate will be reduced by [**] percent ([**]%) for any Research Program under or in connection with a Research Plan concerning a Pilot
Target. 
  

	2.	The following new Section 1.46A shall be added to the Agreement: 

 “Optimized
Antibody” means an antibody with proven binding activity against a Target that is (a) provided by Arsanis to Adimab for optimization and/or humanization pursuant to a Research Plan; (b) not a Program Antibody or a Program
Benefited Antibody at the time it is provided to Adimab by Arsanis; and (c) optimized and/or humanized by Adimab for use against such Target pursuant to such Research Plan. For clarity, following optimization by Adimab an Optimized Antibody
becomes a Program Antibody, and if Arsanis exercises its option in Section 3.2 with respect to an Optimized Antibody, then such Optimized Antibody shall also be a Licensed Antibody. 

  
 G-2 

	3.	Section 1.63 of the Agreement is hereby deleted in its entirety and replaced with the following language: 

“Research Plan” means the research plan set forth in Exhibit C, or any research plan providing for a program of research that
the Research Committee may finalize and the Parties approve in writing as provided for in Section 2.2. It is anticipated that there may ultimately be [**] Research Plans under the Collaboration, but the final number of Research Plans is not
currently known. The Research Plan of Exhibit C is “Research Plan 1.” All subsequent Research Plans will be numbered consecutively. All Research Plans shall comply with the applicable requirements stated in Section 2.2. For the
avoidance of doubt, a Research Plan may include the optimization and/or humanization by Adimab of antibodies that were not discovered by Adimab in order to develop Optimized Antibodies. 

 

	4.	Section 1.73 of the Agreement is hereby deleted in its entirety and replaced with the following language: 

“Tail Period” means the [**] months beginning at the end of the Target Nomination Period. 

 

	5.	Section 1.74 of the Agreement is hereby deleted in its entirety and replaced with the following language: 

“Target” means the disease-related biological target of interest to Arsanis that is specifically identified in Research Plan
1, or the disease-related biological target of interest to Arsanis that is specifically identified in any subsequent Research Plan. Different epitopes on or serotypes of the same molecule that is a biological target of interest will not be deemed to
be different Targets, and Target shall be defined by reference to entire molecules rather than individual serotypes/epitopes (although activities may be focused on specific serotype/epitopes). 

A Target shall be deemed a “Pilot Target” if either (i) it is the first Target under the Collaboration, following the
Amendment Effective Date as defined in that certain “Amendment Number One To The Collaboration Agreement”, that is a carbohydrate; or (ii) the Parties mutually agree in writing to designate a particular Target as a Pilot Target. In
all cases, for a Target to be deemed a Pilot Target, it must be clearly designated as such in the related Research Plan. 
  

	6.	Section 1.75 of the Agreement is hereby deleted in its entirety and replaced with the following language: 

“Target Nomination Period” means the period beginning on the Start Date and ending on December 31, 2013. At any time
within [**] days after the closing of an Arsanis Trade Sale, Adimab may terminate the Target Nomination Period upon [**] days’ prior written notice to Arsanis. Notwithstanding anything in Section 2.4(a) to the contrary, prior to the
effective date of termination of the Target Nomination Period by Adimab as set forth above, Arsanis shall notify Adimab in writing of those Research Programs that Arsanis elects (in its sole discretion) to pursue during the Tail Period (or any
portion thereof) and Adimab will provide Arsanis with a schedule of the FTE usage required by Adimab to complete such Research Programs. 

  
 G-3 

	7.	Section 4.4 of the Agreement is hereby deleted in its entirety and replaced with the following language: 

Program Transaction Revenue Payments 

(a) With respect to a Program Transaction in which rights are granted to one or more Licensed Antibodies and/or Products, none of which is, or
is comprised of, an Optimized Antibody (or a modified or derivative form of an Optimized Antibody): Arsanis shall pay to Adimab: (i) [**] percent ([**]%) of all Program Transaction Revenue in connection with such a Program Transaction for which
the Revenue Election is made (other than a Multi-Product Deal or Multi-Target Deal); (ii) [**] percent ([**]%) of Multi-Product Deal Program Transaction Revenue for such a Program Transaction that is a Multi-Product Deal for which the Revenue
Election is made; and (iii) [**] percent ([**]%) of Multi-Target Deal Program Transaction Revenue for all Multi-Target Deals for which the Revenue Election is made. 

(b) With respect to a Program Transaction in which rights are granted to Incensed Antibodies and/or Products that are, or are comprised of,
only Optimized Antibodies (or modified or derivative forms of Optimized Antibodies), Arsanis shall pay to Adimab: (i) [**] percent ([**]%) of all Program Transaction Revenue in connection with such a Program Transaction for which the Revenue
Election is made (other than Multi-Product Deals or Multi-Target Deals); (ii) [**] percent ([**]%) of Multi-Product Deal Program Transaction Revenue for such a Program Transaction that is a Multi-Product Deal for which the Revenue Election is
made; and (iii) [**]percent ([**]%) of Multi-Target Deal Program Transaction Revenue for such a Program Transaction that is a Multi-Target Deal for which the Revenue Election is made. 

(c) With respect to a Program Transactions in which rights are granted to both (i) one or more Licensed Antibodies and/or Products that
are not, and are not comprised of, an Optimized Antibody and (ii) one or more Licensed Antibodies and/or Products that are, or are comprised of, Optimized Antibodies, then Arsanis shall pay to Adimab [**] percent ([**]%) of the Program
Transaction Revenue allocated to Licensed Antibodies described in clause (c)(i) above and [**] percent ([**]%) of the Program Transaction Revenue allocated to Licensed Antibodies described in clause (c)(ii) above. Adimab and Arsanis will negotiate
and endeavor to agree in good faith the allocation of Program Transaction Revenue to each such class of Lincensed Antibody within [**] days after the date of notice from Arsanis of such Program Transaction. If despite good faith efforts the Parties
are unable to agree upon such allocation within such [**] day period, and Adimab has undergone an Adimab Change of Control prior to the Program Transaction, then Arsanis may request that a Third Party determine such allocation by baseball
arbitration pursuant to Section 10.2(b). If despite good faith efforts the Parties are unable to agree upon such allocation within such [**] day period, and Adimab has not undergone an Adimab Change of Control prior to the Program
Transaction, then Arsanis shall not have any right to refer the matter for dispute resolution or baseball arbitration under Section 10.2(b), and there shall be no reduction or adjustment to Program Transaction Revenue in the applicable Program
Transaction for Licensed Antibodies and Products that are, or are comprised of, Optimized Antibodies. 

  
 G-4 

 (d) Each of the foregoing shall be subject to adjustment (if any) under Section 4.3(e) in
the Combination Product circumstances in which it applies. The amounts due under this Section shall be payable on an ongoing basis within [**] days after the calendar month in which Program Transaction Revenue, Multi-Target Deal Program Transaction
Revenue or Multi-Product Deal Program Transaction Revenue, as the case may be, is received. 
  

	8.	Section 4.5(a) of the Agreement is hereby deleted in its entirety and replaced with the following language: 

(a) Royalty Rate for Products. Arsanis shall pay Adimab royalties at the rate of [**]percent ([**]%) of Net Sales of each Product that
is not comprised of any Optimized Antibodies. Arsanis shall pay Adimab royalties at the rate of [**] percent ([**]%) of Net Sales of each Product, the Licensed Antibodies of which are all Optimized Antibodies. In each case such royalties are payable
during the applicable Royalty Term, determined on a country-by-country and Product-by-Product basis in accordance with Section 4.5(b). In the case of a Product comprised of one or more Licensed Antibodies that are Optimized Antibodies and one
or more Licensed Antibodies that are not Optimized Antibodies, the Parties will mutually agree on the applicable blended royalty rate (not to exceed [**] percent ([**]%)) in advance of First Commercial Sale of such Product, and if the Parties have
failed to agree on such percentage in writing within [**] days after Arsanis in writing requests discussions, and Adimab has prior to such time undergone an Adimab Change of Control, then the percentage of Net Sales determined in baseball
arbitration under Section 10.2(b). Arsanis shall have no right to refer the matter for dispute resolution or baseball arbitration under Section 10.2(b) unless Adimab has undergone an Adimab Change of Control prior to the First Commercial
Sale of the applicable Product in the applicable country, 
  

	9.	Section 3.3(c)(i) of the Agreement is hereby amended by deleting the words “of [**] percent ([**]%)” and replacing them with “based on”. 

 

	10.	All other terms and conditions of the Agreement shall remain in full force and effect. 

[remainder of page intentionally blank] 

  
 G-5 

 IN WITNESS WHEREOF, the
parties have by duly authorized persons executed this Agreement as of the date first written above. 
  

									
	 ARSANIS, INC.:
	 		 	 ADIMAB, LLC:

					
	Sign:	 	 /s/ Jonathan Sheller
	 		 	Sign:	 	 /s/ Errick Anderson

	Print Name: Jonathan Sheller	 		 	Print Name: Errik Anderson
	Title: Director of Operations & Finance	 		 	Title: Chief Operating Officer
	Dated: 02/11/2013	 		 	Date: 02/11/2013

  
 G-6 

 AMENDMENT NUMBER TWO 

TO THE 
 COLLABORATION
AGREEMENT 
 THIS AMENDMENT NUMBER TWO (the
“Amendment”) dated January 16, 2014 (the “Amendment Effective Date”) amends the COLLABORATION AGREEMENT (the “Agreement”) dated as of
May 1, 2011 (the “Original Effective Date”), as amended, by and between ADIMAB, LLC, a Delaware limited liability company having an address at 7 Lucent Drive, Lebanon, NH 03766
(“Adimab”) and ARSANIS, INC., a Delaware corporation having an address at 7 Lucent Drive, Lebanon, NH 03766 (together with Arsanis Biosciences GmbH, an
Austrian entity having an address at Helmut-Qualtinger-Gasse 2, Vienna, A-1030, Austria, collectively “Arsanis”). Capitalized terms used herein and not otherwise defined shall have the meanings ascribed to such words in the
Agreement. 
 BACKGROUND 
  

	 	1.	The Parties wish to extend the Target Nomination Period for three months. 

NOW, THEREFORE, in consideration of the foregoing premises and the mutual covenants set
forth below, and for other good and valuable consideration, the receipt of which is hereby acknowledged, Adimab and Arsanis hereby agree as follows: 
  

	1.	Section 1.75 of the Agreement is hereby deleted in its entirety and replaced with the following language: 

“Target Nomination Period” means the period beginning on the Start Date and ending on March 31, 2014. At any time within
[**] days after the closing of an Arsanis Trade Sale, Adimab may terminate the Target Nomination Period upon [**] days’ prior written notice to Arsanis. Notwithstanding anything in Section 2.4(a) to the contrary, prior to the effective
date of termination of the Target Nomination Period by Adimab as set forth above, Arsanis shall notify Adimab in writing of those Research Programs that Arsanis elects (in its sole discretion) to pursue during the Tail Period (or any portion
thereof) and Adimab will provide Arsanis with a schedule of the FTE usage required by Adimab to complete such Research Programs. 
  

	2.	All other terms and conditions of the Agreement shall remain in full force and effect. 

[remainder of page intentionally blank] 

 IN WITNESS WHEREOF, the
Parties have by duly authorized persons executed this Agreement as of the date first written above. 
  

									
	 ARSANIS, INC.:
	 		 	 ADIMAB, LLC:

					
	Sign:	 	/s/ Eszter Nagy	 		 	Sign:	 	/s/ Errik Anderson
	Print Name: Eszter Nagy	 		 	Print Name:	 	Errik Anderson
	Title: CSO	 		 	Title:	 	COO
	Dated: 01.16.2014	 		 	Date:	 	1-17-14

 AMENDMENT NUMBER THREE 

TO THE 
 COLLABORATION
AGREEMENT 
 THIS AMENDMENT NUMBER THREE (the
“Amendment”) dated January 22 2015 (the “Amendment Effective Date”) amends the COLLABORATION AGREEMENT (the “Agreement”) dated as of
May 1, 2011 (the “Original Effective Date”), as amended, by and between Adimab, LLC, a Delaware limited liability company having an address at 7 Lucent Drive, Lebanon, NH 03766 (“Adimab”) and
ARSANIS, INC., a Delaware corporation having an address at 7 Lucent Drive, Lebanon, NH 03766 (together with Arsanis Biosciences GmbH, an Austrian entity having an address at
Helmut-Qualtinger-Gasse 2, Vienna, A-1030, Austria, collectively “Arsanis”). Capitalized terms used herein and not otherwise defined shall have the meanings ascribed to such words in the Agreement. 

BACKGROUND 

1. The Parties wish to open a new Target Nomination Period for the three months beginning January 1, 2015 and ending on March 31,
2015 (the “2015 Target Nomination Period”). 
 NOW, THEREFORE, in
consideration of the foregoing premises and the mutual covenants set forth below, and for other good and valuable consideration, the receipt of which is hereby acknowledged, Adimab and Arsanis hereby agree as follows: 

 

	1.	The following new Section 1,75A is hereby added to the Agreement: 

 “2015 Target
Nomination Period” means the period beginning on the January 1, 2015 and ending on March 31, 2015. At any gtime within [**] days after the closing of an Arsanis Trade Sale, Adimab may terminate the 2015 Target Nomination Period
upon [**] days’ prior written notice to Arsanis. The 2015 Target Nomination Period shall be a Target Nomination for all purposes under this Agreement other than Section 2.4(a), which shall not apply to the 2015 Target Nomination Period.
For clarity, the 2015 Target Nomination Period shall be followed by a Tail Period. No later than [**] prior to the expiration of the 2015 Target Nomination Period, Arsanis shall notify Adimab in writing of those Research Programs that Arsanis elects
(in its sole discretion) to pursue during the Tail Period (or any portion thereof) and Adimab will provide Arsanis with a schedule of the FTE usage required by Adimab to complete such Research Programs. During the 2015 Target Nomination Period and
the Tail Period Adimab will devote the number of FTEs required to complete such Research Programs, however, Adimab’s aggregate FTE commitment during the Tail Period shall not exceed [**] FTEs per year over such period taken as a whole unless
agreed by the Parties in writing. Adimab shall not be required during the Target Nomination Period or during the Tail Period to devote any FTEs to performing Research Programs, other than FTEs funded by Arsanis under Section 4.2. In addition,
the last sentence of Section 4.2(a) shall not apply to the 2015 Target Nomination Period, 
  

	2.	All other terms and conditions of the Agreement shall remain in full force and effect. 

 [remainder of page intentionally blank] 

 IN WITNESS WHEREOF, the Parties have by duly
authorized persons executed this Agreement as of the date first written above. 
  

									
	 ARSANIS, INC.:
	 		 	 ADIMAB, LLC:

					
	Sign:	 	/s/ Eszter Nagy	 		 	Sign:	 	/s/ Tillman Gerngross
	Print Name: Eszter Nagy	 		 	Print Name: Tillman Gerngross
	Title: CSO	 		 	Title: CEO
	Dated: 21.01.2015	 		 	Date: 1/22/2015

 EXECUTION VERSION 

AMENDMENT NUMBER FOUR 

TO THE 
 COLLABORATION
AGREEMENT 
 This Amendment Number Four to the Collaboration Agreement (the “Fourth Amendment”) is entered into on
April 21, 2017 (the “Fourth Amendment Effective Date”) by and between Adimab, LLC, a Delaware limited liability company having an address at 7 Lucent Drive, Lebanon, NH 03766 (“Adimab”) and Arsanis, Inc., a
Delaware corporation having an address at 890 Winter Street, Suite 230, Waltham, MA 02451 (together with Arsanis Biosciences GmbH, an Austrian entity having an address at Helmut-Qualtinger-Gasse 2, Vienna, A-1030, Austria, collectively,
“Arsanis”). 
 BACKGROUND 

 

	A.	Arsanis and Adimab are the parties to a Collaboration Agreement dated as of May 1, 2011, as previously amended (as so amended, the “Original Agreement”); 

 

	B.	Substantially concurrently with the execution of this Fourth Amendment, Arsanis and the Bill & Melinda Gates Foundation (the “Foundation”) are entering into a letter agreement (the
“Letter Agreement”) under which the Foundation obtains certain rights to the antibodies ASN-1, ASN-2 and ASN-3 (the “Antibodies”); 

 

	C.	The Antibodies are Program-Benefitted Antibodies for which Arsanis has timely exercised an Option under the Original Agreement; and 

  

	D.	Arsanis wishes to amend the Original Agreement as it applies to the Antibodies in order to permit Arsanis to enter into and perform under the Letter Agreement and other related agreements with the Foundation as
contemplated thereunder (the “Foundation Program Transaction” as further defined below, which, for clarity, is a Program Transaction), and Adimab is willing to so amend the Original Agreement, all as set forth in this Fourth
Amendment. 

 AGREEMENT 

NOW, THEREFORE, in consideration of the foregoing premises and the mutual covenants set forth below, and
for other good and valuable consideration, the receipt and sufficiency of which is hereby acknowledged, Adimab and Arsanis agree as follows: 
  

	 	1.	Effect of Amendment. 

 (a) Application to the Antibodies. Upon execution
of this Fourth Amendment, the Original Agreement as amended by this Fourth Amendment will apply to the use of the Antibodies in connection with the Foundation Program Transaction but, for all other purposes, except as expressly stated in this Fourth
Amendment, the Original Agreement will remain unchanged and in full force and effect. For avoidance of doubt, nothing in this Fourth Amendment affects (i) the application of the Original Agreement to any antibodies other than the Antibodies or
(ii) the use of the Antibodies by Arsanis outside of the Foundation Program Transaction. 

  

					
	CONFIDENTIAL	  	Page 1 of 8	  	

 (b) Royalty Election. Arsanis hereby exercises the Royalty Election with respect to the
Foundation Program Transaction. 
 2. Additional Definitions. The following additional definitions are added to the Original
Agreement: 
 “1.81 Developing Countries” has the meaning given to it in the Letter Agreement. The Letter
Agreement provides that Adimab’s consent is required for any change to the Developing Countries, such consent not to be unreasonably withheld. 

1.82 “Foundation” means the Bill & Melinda Gates Foundation. 

1.83 “Foundation Program Transaction” means the transactions contemplated by the Letter Agreement and the
financing and other documents entered into by Arsanis and the Foundation substantially concurrently with the Letter Agreement. 

1.84 “Foundation Selling Party” means Arsanis, its Affiliates, or their counterparties in the Foundation Program
Transaction (including the Foundation, its designee(s), sublicensees, and Foundation-supported Entities and their respective Affiliates). 

1.85 “Foundation-supported Entity” has the meaning given to it in the Letter Agreement. 

1.86 “Global Access Commitment” means the rights, licenses and obligations of Arsanis and the Foundation under
Section 3 of the Letter Agreement (including the rights, licenses and obligations of Arsanis and the Foundation under the grant and other agreements specifically contemplated thereby) with respect to the neonatal sepsis programs described
therein. For clarity, the Global Access Commitment does not include any commitment for Adimab to provide services or to grant a license or transfer of Adimab Platform/Core Technology beyond what is contained in Article 3 of the Original Agreement
prior the Fourth Amendment Effective Date set forth the Fourth Amendment to this Agreement. 
 1.87 “Letter
Agreement” means the letter agreement between Arsanis and the Foundation dated April 24, 2017. 

  

					
	CONFIDENTIAL	  	Page 2 of 8	  	

 1.88 “NGO Sales” means sales and dispositions of Products by or on
behalf of the Foundation Selling Parties in fulfillment of the Global Access Commitments to the extent that the gross amounts invoiced and the fair market value of non-cash consideration received by the Foundation Selling Parties for such sales and
dispositions of Products does not exceed the Foundation Selling Party’s recognized cost of goods sold as calculated in accordance with the Foundation Selling Party’s usual and customary accounting methods, which are in accordance with
GAAP. For clarity, to the extent that the gross amounts invoiced and the fair market value of non-cash consideration received by the Foundation Selling Parties for sales and dispositions of Products in fulfillment of the Global Access Commitment
exceed such recognized cost of goods in the foregoing sentence, the amount of such excess shall be included in the calculation of “Foundation Program Transaction Net Sales” (and shall not be considered “NGO Sales”). 

3. New Foundation Program Transaction Net Sales Definition. The following new Section 1.43A is added to the Original
Agreement: 
 1.43A “Foundation Program Transaction Net Sales means the gross amount invoiced by a
Foundation Selling Party for the sale, transfer or other disposition of Product to Third Parties other than a Foundation Selling Party (in final form for end use or in whatever form is sold to Third Parties who are not Program Transaction
counterparties, Foundation Selling Parties, or their respective Affiliates, to the extent such sales are not NGO Sales, less any of the following applicable deductions to the extent actually granted and included in the invoiced amounts: 

(a) normal, customary trade discounts (including volume discounts), credits, chargebacks, rebates, and allowances and
adjustments for rejections, recalls, outdated products, and returns, in each case whether voluntary or required; 

(b) freight, shipping, and insurance; 

(c) sales, use, excise, value-added and similar customs, taxes, tariffs or duties and other governmental charges imposed
on such sale, transfer, or other disposition (but in no case taxes on income); 
 (d) credits actually given or
allowances actually made for wastage replacement, Medicare/Medicaid rebates, indigent patient and similar programs to provide Product for free; or 

(e) amounts written off by reason of uncollectible debt solely with respect to payments payable for Product to the
extent consistent with Accounting Standards, as determined on a country-by-country basis, but such deduction for uncollectible debt shall not to exceed [**] percent ([**]%) of gross amounts invoiced country-by-country in any twelve (12) month
period. 

  

					
	CONFIDENTIAL	  	Page 3 of 8	  	

 Even if there is overlap between any of deductions (a)—(i), each individual
item shall only be deducted once in each Foundation Program Transaction Net Sales calculation. 
 Foundation Program
Transaction Net Sales calculated as described above shall be adjusted for Combination Products, as provided in Section 4.5(c). The same adjustment shall be applied to product bundles (in the countries where bundling is permitted under
anti-trust law, if any). 
 Foundation Program Transaction Net Sales excludes amounts from sales or other dispositions of
Product between Arsanis and any of its Affiliates, and other Foundation Selling Parties, solely to the extent that such entity purchasing a Product either (a) resells such Product to another Third Party not Affiliated with any of them and such
resale is included in Foundation Program Transaction Net Sales, or (b) the quantities are for use to be provided free to patients in a Product clinical trial. 

NGO Sales are not (except to the extent set forth in Section 1.88 (NGO Sales)) sales or other dispositions of Products for
purposes of this definition of “Foundation Program Transaction Net Sales” or for purposes of Article 4 (Financial Terms) hereof. For clarity, sale of a Product by a Foundation Selling Party to another Foundation Selling Party at a price
that does not exceed the Foundation Selling Party’s recognized cost of goods sold as calculated in accordance with the Foundation Selling Party’s usual and customary accounting methods, which are in accordance with GAAP, for resale by such
entity to a Third Party (other than a Foundation Selling Party) shall not be deemed a sale for purposes of this definition of “Foundation Program Transaction Net Sales”; provided, however, that the first sale thereafter by a Foundation
Selling Party to a Third Party (other than a Foundation Selling Party) shall be included in the computation of Foundation Program Transaction Net Sales. If a Foundation Selling Party sells or disposes of a Product to a Third Party (other than a
Foundation Selling Party) in a country in a transaction that is not an arm’s-length sale (defined below), the gross amount invoiced for such Product for purposes of calculating Foundation Program Transaction Net Sales for such transaction shall
be deemed to equal the weighted (by sales volume) average sale price of such Product in such country to arm’s-length purchasers during the calendar quarter in which such sale or disposition occurs. For purposes of the foregoing, an
“arm’s-length sale” is a sale of Product solely for cash consideration to a Third Party that is unaffiliated with the Foundation Selling Party.” 

  

					
	CONFIDENTIAL	  	Page 4 of 8	  	

 4. New Section 4.5(f). The following new Section 4.5(f) is added to the Original
Agreement: 
 (f) Application to Foundation Program Transaction. Notwithstanding anything to the contrary in this
Section 4.5 and elsewhere in this Agreement, (i) any royalties due to Adimab resulting from sales and dispositions of Products in the course of the Foundation Program Transaction will be calculated using Section 1.43A (Foundation
Program Transaction Net Sales) instead of Section 1.43 (Net Sales), and (ii) with regard to such sales and dispositions of Products only, all references in this Agreement to “Net Sales” shall be deemed to refer to
“Foundation Program Transaction Net Sales”. In addition, for the sake of convenience and efficiency, if requested by the Foundation and Arsanis, Adimab may allow the Foundation, its designee(s), sublicensees or Foundation-supported
entities or their respective Affiliates to pay directly to Adimab any royalty owed to Adimab as a result of sales made by a Foundation Selling Party; provided, however, that in the event such payment is less than what would be due to Adimab under
this Agreement, then Arsanis shall promptly pay the difference directly to Adimab. 
 5. Pass-Through Obligations. 

(a) Notwithstanding anything to the contrary in the Original Agreement, (including, without limitation, Sections 3.3, 4.10, 4.11 and 8.2 of
the Original Agreement), and except as provided in Section 5(b), Arsanis will not be required to (x) impose on the Foundation, or (y) impose on, or require the Foundation or any Foundation-supported Entity to impose on, any Third
Party to which the Foundation grants a sublicense under the rights to the Antibodies granted by Arsanis to the Foundation under the Letter Agreement to conduct activities in furtherance of the sale or other distribution of Products in the Developing
Countries (each, a “Qualified Sublicensee,” and any sublicense described in this Section 5(a), a “Qualified Sublicense”) any: 

(i) restriction or limit the identity or form of the sublicensee; 

(ii) any royalty or financial obligations other than the [**]% royalty specified in the Original Agreement as amended by this
Fourth Amendment (to the extent such royalty is applicable); 
 (iii) obligation on the Foundation to be responsible for the
acts or omissions of any sublicensee of any tier, including for breach of the sublicense agreement or otherwise; 

  

					
	CONFIDENTIAL	  	Page 5 of 8	  	

 (iv) requirement that a sublicensee grant intellectual property rights or
licenses to Adimab or Arsanis (except with respect to improvements to the Adimab platform intellectual property); 
 (v)
obligation on the Foundation to indemnify or defend Adimab or Arsanis for its own acts or for acts or omissions of sublicensees of any tier; or 

(vi) obligation to permit an audit of the Foundation’s records. 

(b) Notwithstanding anything to the contrary in Section 5(a) of this Fourth Amendment, if in any Qualified Sublicense or any other
sublicense the Foundation grants to its sublicensee rights to conduct activities in furtherance of the sale or other distribution of Products for the benefit of patients outside the Developing Countries, Arsanis will require that all applicable
obligations of the Original Agreement as amended by this Fourth Amendment (including, without limitation, Sections 3.3, 4.10, 4.11 and 8.2 of the Original Agreement) that are required to be imposed on sublicensees under the Original Agreement apply
to the extent that such sublicensee is exercising its rights in furtherance of the sale or other distribution of Products outside the Developing Countries, but only to the extent required under the Original Agreement as amended by this Fourth
Amendment without regard to Section 5(a) of this Fourth Amendment. 
 (c) Notwithstanding anything to the contrary in Section 5(a)
of this Fourth Amendment, Arsanis will ensure that any sublicense granted by the Foundation will (i) provide the Foundation with the right to terminate the sublicensee’s rights to any rights covered by the Adimab Agreement granted under
the sublicense for uncured material breach of the sublicense agreement as it pertains to those rights, and (ii) state that both Adimab and Arsanis are intended third party beneficiaries of the relevant terms of the sublicense agreement that
affect or relate to any rights or obligations under the Adimab Agreement, as the case may be, including without limitation with respect to indemnification, with the right to enforce those terms, and including without limitation the right to enforce
the termination of the sublicense; provided that, to the extent the sublicense includes rights other than rights covered by the Adimab Agreement, such termination will not apply to such other rights and neither Adimab nor Arsanis will be entitled to
enforce any termination of such rights. Further, and notwithstanding anything to the contrary in Section 5(a), Arsanis will require the Foundation to impose on Qualified Sublicensees the indemnification and audit obligations required under the
Original Agreement as amended by this Fourth Amendment without regard to Sections 5(a) or 5(b) of this Fourth Amendment, to which Arsanis and Adimab will be third party beneficiaries. 

(d) At the request of Arsanis, Adimab will use good faith and reasonable efforts to work with Arsanis and the Foundation to help ensure that
the sublicenses can be used for the achievement of the Charitable Purpose (as that term is defined in the Letter Agreement) without undue restrictions, including considering in good faith waivers or consents to under the Original Agreement as amend
by this Fourth Amendment. 
 (e) For clarity, none of the foregoing modifies or waives Arsanis’ obligation to indemnify Adimab pursuant
to Section 8.2 of the Original Agreement with respect to the acts and omissions of the Foundation and the Foundation’s sublicensees. 

  

					
	CONFIDENTIAL	  	Page 6 of 8	  	

 6. Publication. Section 6.8 (Publication) of the
Original Agreement is deleted in its entirety and replaced with the following: 
 “6.8 Publication. Arsanis may publish or
present the results of the Collaboration and/or the results of evaluation of Licensed Antibodies (including during the applicable Option Terms), in each case solely with respect to Licensed Antibodies and/or their Target(s). If such publication or
presentation contains Adimab’s Confidential Information, Arsanis shall submit such publication or presentation for prior review and approval by Adimab for patentability and protection of Adimab’s Confidential Information as provided in
this Section 6.8 (and subject to Section 6.2). Arsanis may not proceed with such publications or presentations containing Adimab’s Confidential Information unless approved of in advance in writing by Adimab in its sole discretion.
Arsanis will provide to Adimab the opportunity to review any proposed abstracts, manuscripts or summaries of presentations that contain Adimab’s Confidential Information. Adimab will designate a person or persons who will be responsible for
reviewing such publications. Such designated person will respond in writing promptly and in no event later than [**] days after receipt of the proposed material with either approval of the proposed material or a specific statement of concern, based
upon either the need to seek patent protection or delete Adimab Confidential Information or concern regarding competitive disadvantage arising from the proposal. In the event of concern, Arsanis agrees not to submit such publication or to make such
presentation that contains Adimab’s Confidential Information until Adimab is given a reasonable period of time (not to exceed [**] days) to seek patent protection for any material in such publication or presentation that it believes is
patentable and that it has the right to patent, or to resolve any other issues, and Arsanis will remove from such proposed publication any Confidential Information of Adimab as requested by Adimab.” 

7. Non-Terminable License to Foundation. Notwithstanding anything to the contrary in the Original Agreement, Arsanis may grant
to the Foundation a non-terminable, perpetual, irrevocable license or sublicense under the rights covered by the Original Agreement; provided that, (a) neither the Foundation nor any Foundation-supported Entity has the right to grant a
non-terminable sublicense of such rights to any third party, and (b) each such sublicense meets the requirements set forth in Section 5 of this Fourth Amendment including, but not limited to, terms meeting the requirements of
Section 5(c) of this Fourth Amendment. 
 8. Capitalized Terms. Capitalized terms used in this Fourth Amendment
and not otherwise defined in this Fourth Amendment have the meanings ascribed to them in the Original Agreement. 

  

					
	CONFIDENTIAL	  	Page 7 of 8	  	

 IN WITNESS WHEREOF, the Parties have by duly authorized persons executed this Fourth
Amendment to be effective as of the Fourth Amendment Effective Date.  
  

									
	 “Arsanis”
 Arsanis,
Inc.
	 		 	 “Adimab”
 Adimab,
LLC

					
	By:	 	/s/ Michael P. Gray	 		 	By:	 	/s/ Tillman Gerngross
	Name:	 	Michael P. Gray	 		 	Name:	 	Tillman Gerngross
	Title:	 	CFO/CBO	 		 	Title:	 	CEO

  

					
	CONFIDENTIAL	  	Page 8 of 8	  	

 

 
  

			
		  	 Arsanis Biosciences GmbH,

Helmut-Qualtinger-Gasse 2,
 1-1030 Vienna,

Austria

 Adimab, Inc 
 16 Cavendish Court

 Lebanon, NH 03766 
  

	Att:	CEO 

  

			
		  	28 May 2013

 Dear Dr Gerngross, 
 Re:
Adimab LLC / Arsanis Inc Agreement dated 1st May 2011: Trigger of license option for the antibodies developed by Adimab for the Arsanis Staphylococcus aureus program,
first antigen. 
 As provided for in section 3.2 of the above Collaboration Agreement, Arsanis requests to trigger the exclusive option to obtain the
licenses and assignment of corresponding Antibody Sequences for antibodies delivered to Arsanis by Adimab under the Staphylococcus aureus program. These antibodies are listed according to target antigen in the following appended
tables. 
  

	
	Yours sincerely,
	
	/s/ Eszter Nagy
	
	 Dr Eszter Nagy
 Co-founder and CSO, Arsanis
Biosciences Inc
 Managing Director, Arsanis Biosciences GmbH

 Read and confirmed by: 
  

	
	/s/ Tillman Gerngross
	
	Dr Tillman Gerngross CEO Adimab Inc

 Arsanis Biosciences GmbH, Marxbox, Helmut-Qualtinger-Gasse 2, A-1030 Vienna, Austria 

FB-Nr. 354305 M - HG Wien; ATU66221625 

Tel.:+43 1 799 0117; E-mail: office@arsanis.com; Internet: www.arsanis.com 

  
 Page | 1 of 5 

 Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of 4
pages were omitted. [**] 

  
 Page | 5 of 5 

 

 
  

			
		  	 Arsanis Biosciences GmbH,

Helmut-Qualtinger-Gasse 2,
 A-1030 Vienna,

Austria

 Adimab, Inc 
 7 Lucent Drive 

Lebanon, NH 03766 
  

	Att:	CEO 

  

			
		  	29 January 2014

 Dear Dr Gerngross, 
 Re:
Adimab LLC / Arsanis Inc Agreement dated 1st May 2011: Trigger of license option for the antibodies developed by Adimab for the Arsanis Staphylococcus aureus program,
second antigen: [**]. 
 As provided for in section 3.2 of the above Collaboration Agreement, Arsanis requests to trigger the exclusive option to obtain
the licenses and assignment of corresponding Antibody Sequences for antibodies delivered to Arsanis by Adimab under the Staphylococcus aureus program for [**]. These antibodies are listed according to target antigen in the
following appended tables. 
  

	
	Yours sincerely,
	
	/s/ Eszter Nagy
	
	 Dr Eszter Nagy
 Co-founder and CSO, Arsanis
Inc
 Managing Director, Arsanis Biosciences GmbH

 Read and confirmed by: 
  

	
	/s/ Tillman Gerngross
	
	Dr Tillman Gerngross CEO Adimab Inc

 Arsanis Biosciences GmbH, Marxbox, Helmut-Qualtinger-Gasse 2, A-1030 Vienna, Austria 

FB-Nr. 354305 M - HG Wien; ATU66221625 

Tel.:+43 1 799 0117; E-mail: office@arsanis.com; Internet: www.arsanis.com 

  
 Page | 1 of 3 

 Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of 2
pages were omitted. [**] 

  
 Page | 2 of 3 

 

 
  

			
		  	 Arsanis Biosciences GmbH,

Helmut-Qualtinger-Gasse 2,
 1-1030 Vienna,

Austria

 Adimab, Inc 
 16 Cavendish Court

 Lebanon, NH 03766 
  

	Att:	CEO 

  

			
		  	24rd April 2014

 Dear Dr Gerngross, 
 Re:
Adimab LLC / Arsanis Inc Agreement dated 1st May 2011: Trigger of license option for the antibodies developed by Adimab for the Arsanis Staphylococcus aureus program,
third antigen: [**]. 
 As provided for in section 3.2 of the above Collaboration Agreement, Arsanis requests to trigger the exclusive option to obtain
the licenses and assignment of corresponding Antibody Sequences for antibodies delivered to Arsanis by Adimab under the Staphylococcus aureus program for [**]. These antibodies are listed according to target antigen in the
following appended tables. 
  

	
	Yours sincerely,
	
	/s/ Eszter Nagy
	
	 Dr Eszter Nagy
 Co-founder and CSO, Arsanis
Inc
 Managing Director, Arsanis Biosciences GmbH

 Read and confirmed by: 
  

	
	/s/ Tillman Gerngross
	
	Dr Tillman Gerngross CEO Adimab Inc

 Arsanis Biosciences GmbH, Marxbox, Helmut-Qualtinger-Gasse 2, A-1030 Vienna, Austria 

FB-Nr. 354305 M - HG Wien; ATU66221625 

Tel.:+43 1 799 0117; E-mail: office@arsanis.com; Internet: www.arsanis.com 

  
 Page | 1 of 3 

 Confidential Materials omitted and filed separately with the Securities and Exchange Commission. A total of 2
pages were omitted. [**] 

  
 Page | 3 of 3

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