Exhibit 10.37

SHARE PURCHASE AGREEMENT

This SHARE PURCHASE AGREEMENT (this “Agreement”) is entered into as of November
15, 2017 (the “Effective Date”), by and between New Enterprise Associates 16,
L.P., a Delaware limited partnership (the “Investor”), and Arsanis, Inc., a
Delaware corporation (the “Company”).

WHEREAS, the Company is proposing to issue and sell to the Investor (the
“Offering”) $20,000,000 of the Company’s common stock, $0.001 par value per
share (the “Common Stock”), in connection with the Company’s initial public
offering of Common Stock (“IPO”), pursuant to the terms and subject to the
conditions set forth in this Agreement;

WHEREAS, the parties hereto have executed this Agreement on the Effective Date,
which is prior to the effectiveness of the registration statement on Form S-1
filed by the Company with the Securities and Exchange Commission (the “SEC”) for
the Company’s IPO;

WHEREAS, the closing of the Offering shall take place concurrently with the
closing of the IPO and at a price per share equal to the initial public offering
price per share that the Common Stock is sold to the public in the IPO,
provided, however, that such initial public offering price per share shall not
exceed $10.00 per share (the “IPO Price” and such time, the “IPO Closing Time”),
as set forth on the cover of the final prospectus filed with the SEC;

WHEREAS, the Shares are being offered to the Investor pursuant to a private
placement exemption from registration under the Securities Act of 1933, as
amended (the “Securities Act”); and

WHEREAS, in order to effect the IPO, the Company shall enter into an
Underwriting Agreement (the “Underwriting Agreement”) with Citigroup Global
Markets Inc., Cowen and Company, LLC and Piper Jaffray & Co., as representative
of the several underwriters named therein (the “Underwriters”), substantially in
the form attached hereto as Exhibit A;

NOW, THEREFORE, in consideration of the foregoing and the mutual promises and
covenants set forth below, the parties hereto hereby agree as follows:

1. Sale of Shares.

(a) Purchase and Sale. Subject to the terms and conditions set forth in this
Agreement, the Company hereby agrees to sell to the Investor, and the Investor
hereby agrees to purchase from the Company, $20,000,000 of the Company’s Common
Stock (the “Investment Amount”) at the IPO Price. The number of shares of Common
Stock to be sold by the Company and purchased by the Investor hereunder (the
“Shares”) shall equal the number of shares determined by dividing the Investment
Amount by the IPO Price (rounded down to the nearest whole share). The total
purchase price to be paid by the Investor for the Shares is equal to (i) the
number of Shares multiplied by (ii) the IPO Price (the “Purchase Price”).

 

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(b) Closing. The closing of the purchase and sale of the Shares (the “Closing”)
shall take place at the offices of Davis Polk & Wardwell LLP, 450 Lexington
Avenue, New York, New York 10017, or at such other place as shall be agreed upon
by the parties hereto, after the satisfaction or waiver of each of the
conditions set forth in Section 4 (other than those conditions that by their
nature are to be satisfied at the Closing, but subject to the fulfillment or
waiver of those conditions) concurrently with the IPO Closing Time. At the
Closing, (i) the Company shall cause the Company’s transfer agent to deliver the
Shares to the Investor registered in the name of the Investor, and (ii) the
Purchase Price for the Shares shall be delivered by or on behalf of the Investor
to the Company.

(c) Payment of Purchase Price. Payment by the Investor of the Purchase Price to
the Company shall be made at the Closing by wire transfer of immediately
available funds equal to the aggregate purchase price for the Shares to an
account specified in writing by the Company.

Payment of the Purchase Price for the Shares shall be made against delivery to
the Investor of the Shares, which Shares shall be uncertificated and shall be
registered in the name of the Investor on the books of the Company by the
Company’s transfer agent.

2. Representations and Warranties.

2.1 Representations and Warranties of the Company. The Company represents and
warrants to the Investor as follows:

(a) The representations and warranties of the Company set forth in the
Underwriting Agreement are true and correct on and as of the date hereof, with
the same effect as if made herein on the date hereof (except to the extent any
such representations and warranties expressly relate to a particular date, in
which case such representations and warranties are true and correct as of such
particular date) (after giving effect to any materiality or other qualifiers
contained therein);

(b) The Company has the full right, power, authority and capacity to enter into
this Agreement and to consummate the transactions contemplated hereby and has
taken all necessary action to authorize the execution, delivery and performance
of this Agreement;

(c) This Agreement constitutes the valid and legally binding obligation of the
Company, enforceable in accordance with its terms, subject to bankruptcy,
reorganization, insolvency and other similar laws affecting the enforcement of
creditors’ rights generally and to general principles of equity. Upon issuance
in accordance with, and payment pursuant to, the terms of this Agreement, the
Shares will be duly authorized, validly issued and fully-paid and nonassessable;

(d) The execution and delivery by the Company of, and the performance by the
Company of its obligations under this Agreement, the issuance, sale and delivery
of the Shares, the consummation of the transactions contemplated herein and
compliance by the Company with its obligations hereunder does not and will not
contravene any provision of applicable law, or the certificate of incorporation
or by laws or other organizational documents of the Company, or any

 

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agreement or other instrument binding upon the Company or the Shares or any
judgment, order or decree of any governmental body, agency or court having
jurisdiction over the Company, and no consent, approval, authorization or order
of, or qualification with, any governmental body or agency is required for the
performance by the Company of its obligations under this Agreement, except, in
each case, where any such contravention or where the failure to obtain any such
consent, approval, authorization or order would not reasonably be expected to
have a material adverse effect on the consummation of the transactions
contemplated hereby;

(e) To the knowledge of the Company, the Company has not taken any action which
could reasonably be expected to cause the sale of the Shares to be sold by the
Company to the Investor to fail to qualify as exempt from the registration
requirements of the Securities Act; and

(f) None of the Company, any predecessor of the Company, any affiliated issuer,
any director, executive officer, other officer of the Company participating in
the Offering, general partner or managing member of the Company, any beneficial
owner of 20% or more of the Company’s outstanding voting equity securities, any
promoter connected with the Company at the time of any sale of the Shares or any
investment manager of the Company (if the Company is a pooled investment fund),
as applicable, is subject to the “bad actor” disqualifications set forth in Rule
506(d)(1) of the Securities Act.

2.2 Representations and Warranties of the Investor. The Investor represents and

warrants to the Company as follows:

(a) (i) It is an institutional “accredited investor” as defined in Rule 501(a)
promulgated under the Securities Act; (ii) it has sufficient knowledge and
experience in investing in companies similar to the Company so as to be able to
evaluate the risks and merits of its investment in the Company and it is able
financially to bear the risks thereof; (iii) it has had an opportunity to
discuss the Company’s business, management and financial affairs with the
Company’s management; (iv) all documents, records, and information pertaining to
its investment in the Common Stock and the Company that have been requested by
it, if any, have been made available or delivered to it prior to the date
hereof; (v) its financial condition is such that it is able to bear the risk of
holding the Shares for an indefinite period of time and can bear the loss of the
entire investment in such Shares; and (vi) it is not purchasing the Shares as
the result of any form of general solicitation or general advertising within the
meaning of Rule 502(c) under the Securities Act or as a result of the Investor's
review of public filings by the Company;

(b) The Investor understands that this Agreement is made in reliance upon the
Investor’s express representations, which it hereby represents and warrants to
the Company, that (i) the Shares being purchased by the Investor are being
acquired for the Investor’s own account (and not on behalf of any other person
or entity) for the purpose of investment and not with a view to, or for sale in
connection with, the distribution thereof, nor with any present intention of
distributing or selling the Shares or any portion thereof, (ii) the Investor was
not organized for the specific purpose of acquiring the Shares and (iii) the
Shares will not be sold by the Investor without registration under the
Securities Act or applicable state securities laws, or an exemption therefrom;

 

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(c) The Investor further understands that the Shares being purchased by the
Investor hereunder have not been registered under the Securities Act or any
state securities laws and are instead being offered and sold in reliance on an
exemption from such registration requirements. The Investor represents and
warrants to the Company that, to the Investor’s knowledge, the Investor has not
taken any action which could reasonably be expected to cause the sale of the
Shares to be sold by the Company to the Investor to fail to qualify as exempt
from the registration requirements of the Securities Act. The Investor further
understands that until such time as the Shares shall have been registered under
the Securities Act and applicable state securities laws or shall have been
transferred in accordance with an opinion of counsel reasonably satisfactory to
the Company that such registration is not required, stop transfer instructions
shall be issued to the Company’s transfer agent and any certificate or
certificates representing such securities shall bear a restrictive legend
stating that such securities have not been registered under the Securities Act
and applicable state securities laws and referring to restrictions on the
transferability and sale thereof.

(d) The Investor further understands that its representations and warranties
hereunder will not preclude disposition of the Shares without registration
thereof, in compliance with Rule 144 promulgated under the Securities Act (“Rule
144”). The Investor understands and acknowledges, however, that there may not be
available when the Investor wishes to sell the Shares, or any portion thereof,
the adequate current public information with respect to the Company which would
permit offers or sales of such securities pursuant to Rule 144, and, therefore,
compliance with the Securities Act or some other exemption from the registration
and prospectus delivery requirements of the Securities Act may be required for
any such offer or sale; and

(e) (i) The Investor is validly existing as a limited partnership in good
standing under the laws of the State of Delaware; (ii) the Investor has all
requisite power and authority to execute and deliver this Agreement; and (iii)
this Agreement constitutes the valid and legally binding obligation of the
Investor, enforceable against the Investor in accordance with its terms, subject
to bankruptcy, reorganization, insolvency and other similar laws affecting the
enforcement of creditors’ rights generally and to general principles of equity.

 

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4. Conditions to the Closing. The obligations of the Company and the Investor
hereunder are subject to the satisfaction of the conditions set forth below on
or before the Closing. If for any reason any of the conditions set forth in this
Section ‎4 are not satisfied or waived by each party entitled to the benefit of
such conditions at or prior to the Closing, then each party by written notice
given to the other parties hereto shall have the right to elect to terminate
this Agreement and each party shall be released from their obligations hereunder
and shall have no further liability hereunder, provided, however, that nothing
contained in this Section ‎4 shall relieve either party from liabilities or
damages arising out of any fraud or willful breach by such party of this
Agreement prior to such termination.

(a) Conditions to the Investor’s Obligations. The Investor’s obligation to
purchase the Shares at the Closing is subject to the satisfaction of the
following conditions:

(i) delivery of an opinion of counsel to the Company, dated the date of the
Closing, substantially in the form attached hereto as Exhibit B;

(ii) the representations and warranties of the Company contained in Section 2.1
shall be true and accurate on and as of the Closing with the same force and
effect as if they had been made at the Closing (except to the extent any such
representations and warranties expressly relate to a particular date, in which
case such representations and warranties are true and correct as of such
particular date) (after giving effect to any materiality or other qualifiers
contained therein); and

(iii) the Shares shall have been delivered to the Investor’s account.

(b) Conditions to the Company’s Obligations. The Company's obligation to sell
the Shares at the Closing is subject to the satisfaction of the following
conditions:

(i) the Investor shall have paid the Purchase Price to the Company by wire
transfer of immediately available funds as specified in Section 1(c) of this
Agreement;

(ii) the representations and warranties of the Investor contained in Section 2.2
shall be true and accurate on and as of the Closing with the same force and
effect as if they had been made at the Closing; and

(iii) the Underwriters shall have purchased, concurrent with the purchase of the
Shares by the Investor hereunder, the Firm Shares (as defined in the
Underwriting Agreement) at the IPO Price (less any underwriting discounts or
commissions).

5. Registration Rights.

(a) Defined Terms. As used in this Section 5, the following terms shall have the
following meanings:

(i) “Prospectus” means (x) the prospectus included in any Registration Statement
contemplated by this Section 5, as amended or supplemented by any prospectus

 

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supplement, with respect to the terms of the offering of any portion of the
Registrable Securities covered by such Registration Statement and by all other
amendments and supplements to the prospectus, including post-effective
amendments and all material incorporated by reference in such prospectus, and
(y) any “free writing prospectus” as defined in Rule 405 promulgated under the
Securities Act.

(ii) “Registrable Securities” means (x) the Shares, and (y) any shares of Common
Stock issued or issuable with respect to the Shares by way of a stock dividend
or stock split or in connection with a combination of shares, recapitalization,
merger, consolidation or other reorganization. As to any particular Registrable
Securities, such securities shall cease to be Registrable Securities when (i) a
Registration Statement covering such securities has been declared effective by
the SEC and such securities have been disposed of pursuant to such effective
Registration Statement, (ii) such securities are sold under circumstances in
which all of the applicable conditions of Rule 144 (or any similar provisions
then in force) are met, (iii) such securities are otherwise transferred and such
securities may be resold without subsequent registration under the Securities
Act, or (iv) such securities shall have ceased to be outstanding.

(iii) “Registration Statement” means any registration statement of the Company
which covers any of the Registrable Securities pursuant to the provisions of
this Section 5, including the Prospectus, amendments and supplements to such
Registration Statement, including post-effective amendments, all exhibits and
all materials incorporated by reference in such Registration Statement.

(b) Demand Registration.

(i) At any time after the date that is 180 days after the Closing, the Investor
may request registration under the Securities Act of all of its Registrable
Securities then held on a Form S-1 or Form S-3 registration statement (or any
successor to each such form) (or, if Form S-1 or Form S-3 is not then available,
on such form of registration statement as is then available to effect a
registration of the Registrable Securities pursuant to this subsection (b)(i))
(each a “Demand Registration”). Each request for a Demand Registration shall
specify the approximate number of Registrable Securities required to be
registered. Upon receipt of a Demand Registration request, the Company shall
cause a Registration Statement to be filed within forty-five (45) days after the
date on which such request was received by the Company. The Company shall not be
required to effect a Demand Registration (A) more than two (2) times for the
Investor; provided, however, that a Registration Statement shall not count as a
Demand Registration requested under this subsection (b)(i)(A) unless and until
it has become effective, or (B) if the Company furnishes to the Investor a
certificate signed by an authorized officer of the Company stating that (a)
within sixty (60) days of receipt of the Demand Registration request under this
subsection (b)(i), the Company expects to file a registration statement for the
public offering of securities for the account of the Company (other than a
registration of securities (x) issuable pursuant to an employee stock option,
stock purchase or similar plan, (y) issuable pursuant to a merger, exchange
offer or a transaction of the type

 

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specified in Rule 145(a) under the Securities Act or (z) in which the only
securities being registered are securities issuable upon conversion of debt
securities which are also being registered), provided, that the Company is
actively employing good faith efforts to cause such registration statement to
become effective, or (b) the Company is engaged in a material transaction or has
an undisclosed material corporate development, in either case, which would be
required to be disclosed in the Registration Statement, and in the good faith
judgment of the Company’s Board of Directors, such disclosure would be
materially detrimental to the Company and its stockholders at such time (in
which case, the Company shall disclose the matter as promptly as reasonably
practicable and thereafter file the Registration Statement, and the Investor
agrees not to disclose any information about such material transaction to third
parties until such disclosure has occurred or such information has entered the
public domain other than through breach of this provision by such Investor),
provided, however, that the Company shall have the right to defer the filing of
the Registration Statement pursuant to this subsection twice in any twelve (12)
month period and any such deferral may not exceed a period of more than sixty
(60) days in the aggregate during such twelve-month period.

(ii) If the Investor requests a Demand Registration and elects to distribute the
Registrable Securities covered by its request in an underwritten offering, the
Investor shall so advise the Company as a part of its request made pursuant to
subsection (b)(i). The Company shall select the investment banking firm or firms
to act as the managing underwriter or underwriters in connection with such
offering; provided, however, that such selection shall be subject to the consent
of the Investor, which consent shall not be unreasonably withheld, delayed or
conditioned.

(c) Requirements of the Company.

(i) In connection with the filing by the Company of any Registration Statement,
the Company shall furnish to the Investor (x) a copy of the Prospectus,
including a preliminary prospectus, in conformity with the requirements of the
Securities Act, and (y) such other documents as the Investor may reasonably
request, in order to facilitate the public sale or other disposition of the
Registrable Securities.

(ii) The Company shall use its reasonable best efforts to cause each
Registration Statement contemplated by this Section 5 to be declared effective
or become effective as soon as practicable following the filing thereof with the
SEC. The Company shall notify the Investor in writing after any Registration
Statement is declared effective.

(iii) In the event of any stock split, stock dividend or transaction with
respect to the Registrable Securities that increases the number of Registrable
Securities, if a then-effective Registration Statement does not cover the resale
of such additional number of Registrable Securities, the Company shall amend or
supplement any Registration Statement to cover such additional number of
Registrable Securities.

 

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(iv) The Company shall use its best efforts to register or qualify the
Registrable Securities covered by any Registration Statement under the
securities laws of each state of the United States; provided, however, that the
Company shall not be required in connection with this subsection (c)(iv) to
qualify as a foreign corporation or execute a general consent to service of
process in any jurisdiction.

(v) If the Company has delivered preliminary or final Prospectuses to the
Investor and, after having done so, the Prospectus is amended or supplemented to
comply with the requirements of the Securities Act, the Company shall promptly
notify the Investor and, if requested by the Company, the Investor shall
immediately cease making offers or sales of shares under the applicable
Registration Statement and return all Prospectuses to the Company. The Company
shall promptly provide the Investor with revised or supplemented Prospectuses
and, following receipt of the revised or supplemented Prospectuses, the Investor
shall be free to resume making offers and sales under the applicable
Registration Statement.

(vi) The Company shall advise the Investor promptly after it shall receive
notice or obtain knowledge of the issuance of any stop order by the SEC delaying
or suspending the effectiveness of any Registration Statement or of the
initiation or threat of any proceeding for that purpose, and it will promptly
use commercially reasonable efforts to prevent the issuance of any stop order or
to obtain its withdrawal at the earliest possible moment if such stop order
should be issued.

(d) Requirements of the Investor. The Company shall not be required to include
any Registrable Securities in any Registration Statement contemplated by this
Section 5 unless the Investor furnishes to the Company, in writing, such
information regarding the Investor and the proposed sale of the Registrable
Securities by the Investor as the Company may reasonably request in writing in
connection with such Registration Statement or as shall be required in
connection therewith by the SEC or any state securities law authorities.

(e) Suspension. The Company may suspend the use of any Registration Statement or
Prospectus (a “Suspension”) by the Investor if the Company determines in good
faith that such Suspension is necessary to (x) delay the disclosure of material
non-public information concerning the Company, the disclosure of which at the
time, in the good faith opinion of the Company’s Board of Directors, would be
materially detrimental to the Company or its stockholders for a registration to
be effected at such time; (y) amend or supplement the affected Registration
Statement or the related Prospectus so that such Registration Statement or
Prospectus shall not include an untrue statement of a material fact or omit to
state a material fact required to be stated therein; or (z) amend or supplement
the affected Registration Statement or Prospectus in order to make the
statements therein, in light of the circumstances under which they were made,
not misleading; provided, however, in each case of clauses (x) through (z), that
the Company shall (a) promptly notify the Investor in writing of such Suspension
and the reasons therefor, but shall not disclose to the Investor any material
non-public information giving rise to a Suspension under clause (x); (b) advise
the Investor in writing to cease all sales under the Registration Statement or
Prospectus until the end of the Suspension; and (c) use its reasonable

 

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best efforts to terminate such Suspension as promptly as practicable. The
Company may not exercise its rights pursuant to this subsection (e) for more
than ninety (90) days in the aggregate in any twelve (12) month period.

(f) Expenses. Except as set forth below, the Company will pay all of the
expenses incurred in connection with complying with this Section 5 (whether or
not any Registration Statement or Prospectus becomes final or effective),
including, without limitation: all registration, filing and printing fees, the
Company’s counsel and accounting fees and expenses, costs and expenses
associated with clearing the Registrable Securities for sale under applicable
state securities laws (including, without limitation, fees, charges and
disbursements of counsel in connection with such clearance), all listing fees,
expenses incurred by the Company (but not the Investor) in connection with any
“road show,” and reasonable fees, charges and disbursements of counsel to the
Investor. The Company shall not be required to pay or reimburse the Investor for
any underwriting discounts or commissions and fees of underwriters, selling
brokers, dealer managers or similar securities industry professionals with
respect to the Registrable Securities being sold.

(g) Indemnification.

(i) The Company agrees to indemnify and hold harmless the Investor, each
underwriter, and each other person, if any, who controls the Investor or
underwriter within the meaning of the Securities Act or the Securities Exchange
Act of 1934, as amended (the “Exchange Act”), from and against any losses,
claims, damages or liabilities to which the Investor, such underwriter or
controlling person may become subject (under the Securities Act, the Exchange
Act, state securities or blue sky laws or otherwise) insofar as such losses,
claims, damages or liabilities (or actions or proceedings in respect thereof)
arise out of, or are based upon, any untrue statement of a material fact
contained in any registration statement covering the Shares or in any
preliminary prospectus or final prospectus contained in such registration
statement, or any amendment or supplement to such registration statement, or the
omission or alleged omission to state a material fact required to be stated
therein or necessary to make the statements therein not misleading, and the
Company will reimburse the Investor for any reasonable legal or other expenses
reasonably incurred in investigating, defending or preparing to defend any such
action, proceeding or claim, or preparing to defend any such action, proceeding
or claim; provided, however, that the Company shall not be liable in any such
case to the extent that such loss, claim, damage or liability arises out of, or
is based upon, an untrue statement made in such registration statement,
preliminary prospectus or prospectus, or any amendment or supplement in reliance
upon and in conformity with written information relating to the Investor
furnished to the Company by or on behalf of the Investor specifically for use in
the preparation thereof or any statement or omission in any prospectus that is
corrected in any subsequent prospectus that was delivered to the Investor prior
to the pertinent sale or sales by the Investor.

(ii) The Investor agrees to indemnify and hold harmless the Company, each
underwriter and each person, if any, who controls the Company within the meaning
of

 

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Section 15 of the Securities Act, each officer of the Company who signs the
registration statement and each director of the Company, from and against any
losses, claims, damages or liabilities to which the Company or any such
underwriter, officer, director or controlling person may become subject under
the Securities Act, the Exchange Act, state securities or blue sky laws or
otherwise, insofar as such losses, claims, damages or liabilities (or actions or
proceedings in respect thereof) arise out of, or are based upon, any untrue
statement of a material fact contained in any registration statement covering
the Shares or in any preliminary prospectus, final prospectus contained in such
registration statement, or any amendment or supplement to such registration
statement or the omission or alleged omission to state a material fact required
to be stated therein or necessary to make the statements therein not misleading,
if such untrue statement or omission was made in reliance upon and in conformity
with written information relating to the Investor furnished by or on behalf of
the Investor specifically for use in preparation of the registration statement,
prospectus, amendment or supplement and the Investor will reimburse the Company,
or such underwriter, officer, director or controlling person, as the case may
be, for any legal or other expenses reasonably incurred in investigating,
defending or preparing to defend any such action, proceeding or claim; provided,
however, that the Investor’s obligation to indemnify the Company shall be
limited to the net amount received by the Investor from the sale of the Shares.

(iii) Promptly after receipt by any indemnified person of a notice of a claim or
the beginning of any action in respect of which indemnity is to be sought
against an indemnifying person pursuant to this Section 5(g), such indemnified
person shall notify the indemnifying person in writing of such claim or of the
commencement of such action, but the omission to so notify the indemnifying
party will not relieve it from any liability which it may have to any
indemnified party under this Section 5(g) (except to the extent that such
omission materially and adversely affects the indemnifying party’s ability to
defend such action). Subject to the provisions hereinafter stated, in case any
such action shall be brought against an indemnified person, the indemnifying
person shall be entitled to participate therein, and, to the extent that it
shall elect by written notice delivered to the indemnified party promptly after
receiving the aforesaid notice from such indemnified party, shall be entitled to
assume the defense thereof, with counsel reasonably satisfactory to such
indemnified person. After notice from the indemnifying person to such
indemnified person of its election to assume the defense thereof, such
indemnifying person shall not be liable to such indemnified person for any legal
expenses subsequently incurred by such indemnified person in connection with the
defense thereof; provided, however, that if there exists or shall exist a
conflict of interest that would make it inappropriate, in the opinion of counsel
to the indemnified person, for the same counsel to represent both the
indemnified person and such indemnifying person or any affiliate or associate
thereof, the indemnified person shall be entitled to retain its own counsel at
the expense of such indemnifying person; provided, however, that no indemnifying
person shall be responsible for the fees and expenses of more than one separate
counsel (together with appropriate local counsel) for all indemnified parties.
In no event shall any indemnifying person be liable in respect of any amounts
paid in settlement of any action unless the indemnifying person shall have
approved the terms of such settlement;

 

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provided, however, that such consent shall not be unreasonably withheld. No
indemnifying person shall, without the prior written consent of the indemnified
person, effect any settlement of any pending or threatened proceeding in respect
of which any indemnified person is or could have been a party and
indemnification could have been sought hereunder by such indemnified person,
unless such settlement includes an unconditional release of such indemnified
person from all liability on claims that are the subject matter of such
proceeding.

(iv) If the indemnification provided for in this Section 5(g) is unavailable to
or insufficient to hold harmless an indemnified party under subsections (g)(i)
or (ii) above in respect of any losses, claims, damages or liabilities (or
actions or proceedings in respect thereof) referred to therein, then each
indemnifying party shall contribute to the amount paid or payable by such
indemnified party as a result of such losses, claims, damages or liabilities (or
actions in respect thereof) in such proportion as is appropriate to reflect the
relative fault of the Company on the one hand and the Investor, as well as any
other selling stockholders under such registration statement on the other in
connection with the statements or omissions or other matters which resulted in
such losses, claims, damages or liabilities (or actions in respect thereof), as
well as any other relevant equitable considerations. The relative fault shall be
determined by reference to, among other things, in the case of an untrue
statement, whether the untrue statement relates to information supplied by the
Company on the one hand or the Investor or other selling stockholder on the
other and the parties’ relative intent, knowledge, access to information and
opportunity to correct or prevent such untrue statement. The Company and the
Investor agree that it would not be just and equitable if contribution pursuant
to this subsection (g)(iv) were determined by pro rata allocation (even if the
Investor and other selling stockholders were treated as one entity for such
purpose) or by any other method of allocation which does not take into account
the equitable considerations referred to above in this subsection (g)(iv). The
amount paid or payable by an indemnified party as a result of the losses,
claims, damages or liabilities (or actions in respect thereof) referred to above
in this subsection (g)(iv) shall be deemed to include any legal or other
expenses reasonably incurred by such indemnified party in connection with
investigating or defending any such action or claim. Notwithstanding the
provisions of this subsection (g)(iv), the Investor shall not be required to
contribute any amount in excess of the amount by which the net amount received
by the Investor from the sale of the Shares to which such loss relates exceeds
the amount of any damages which the Investor has otherwise been required to pay
by reason of such untrue statement. No person guilty of fraudulent
misrepresentation (within the meaning of Section 11(f) of the Securities Act)
shall be entitled to contribution from any person who was not guilty of such
fraudulent misrepresentation.

 

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(h) Survival. The rights and obligation of the Company and the Investor under
this Section 5 shall survive the termination of this Agreement

(i) Termination. All of the Company’s obligations to register the Shares under
this Agreement shall terminate on the earlier of (a) the three year anniversary
of the date of this Agreement or (b) the date on which all of the Shares have
been sold by the Investor.

6. Expenses. The Company will pay the fees, charges and disbursements of counsel
to the Investor in connection with this Offering, provided, however, that such
fees, charges and disbursements shall not exceed $35,000.

7. Successors and Assigns. This Agreement shall be binding upon and inure to the
benefit of the parties hereto and their respective successors and permitted
assigns.

8. Notices. Notices given hereunder shall be deemed to have been duly given,
only if given in writing, and on (i) the date of personal delivery, (ii) on the
date one day after being delivered to a reputable overnight courier with proper
delivery instructions, or (iii) if delivered by facsimile, upon electronic
confirmation of receipt to the party being notified as addressed as follows: (a)
if to the Investor, to: New Enterprise Associates, 1954 Greenspring Drive, Suite
600, Timonium, Maryland 21093, Attention: Louis Citron, with a copy to: Davis
Polk & Wardwell LLP, 450 Lexington Avenue, New York, New York 10017, Attention:
Richard D. Truesdell, Jr., (b) if to the Company, to: Arsanis, Inc., 890 Winter
Street, Suite 230, Waltham, Massachusetts 02451, Attention: René Russo, with a
copy to: Wilmer Cutler Pickering Hale and Dorr LLP, 60 State Street, Boston,
Massachusetts 02109, Attention: Cynthia T. Mazareas.

9. Entire Agreement and Amendments. This Agreement constitutes the entire
agreement of the parties with respect to the subject matter hereof. This
Agreement may be amended or waived if, and only if, such amendment or waiver is
in writing and signed, in the case of an amendment, by each of the parties
hereto or, in the case of a waiver, by the party waiving compliance. No waiver
shall be deemed a waiver of any subsequent breach or default.

10. Governing Law. This Agreement shall be governed by and interpreted in
accordance with the laws of the State of New York without regard to the conflict
of laws principles thereof.

11. Severability. The invalidity or unenforceability of any particular provision
of this Agreement shall not affect the other provisions hereof.

12. Assignment. This Agreement may not be assigned by the Company or the
Investor without the prior written consent of the other parties hereto.

13. Captions. Captions are for convenience only and are not deemed to be part of
this Agreement. All references herein to numbered Sections are to Sections of
this Agreement unless otherwise indicated.

14. Survival. The representations and warranties contained herein shall survive
the Closing.

 

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15. Counterparts. This Agreement may be executed by pdf and in counterparts,
each of which shall be deemed an original, but all of which together shall
constitute one and the same instrument.

16. Further Assurances. The parties agree to execute such further instruments
and to take such further action as may reasonably be necessary to carry out the
intent of this Agreement.

17. Termination. This Agreement shall automatically terminate upon the earliest
to occur, if any, of: (a) either the Company, on the one hand, or the
Underwriters, on the other hand, advising the other in writing, prior to the
execution of the Underwriting Agreement, that they have determined not to
proceed with the IPO, (b) termination of the Underwriting Agreement (other than
the provisions thereof which survive termination) prior to the sale of any of
the Common Stock to the Underwriters, (c) the initial public offering price per
share that the Common Stock is sold to the public in the IPO exceeds $10.00 per
share, (d) the registration statement filed with the SEC with respect to the IPO
is withdrawn, (e) the Underwriting Agreement has not become effective by
February 16, 2018, or (f) the written consent of each of the Company and the
Investor.

[Remainder of Page Intentionally Left Blank]

 

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IN WITNESS WHEREOF, the parties hereto have executed this Agreement to be
effective as of the date first set forth above.

 

ARSANIS, INC.

 

 

 

By:

 

/s/ René Russo

 

 

Name:René Russo

 

 

Title:President and Chief Executive Officer

 

NEW ENTERPRISE ASSOCIATES 16, L.P.

 

 

 

By:

 

NEA Partners 16, L.P.

By:

 

NEA 16 GP, LLC

 

 

 

By:

 

/s/ Louis S. Citron

 

 

Name: Louis S. Citron

 

 

Title:Chief Legal Officer

 

 

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EXHIBIT A

 

Form of Underwriting Agreement

 

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Arsanis, Inc.

4,000,000 Shares

Common Stock

($0.001 par value)

Underwriting Agreement

New York, New York

November 15, 2017

Citigroup Global Markets Inc.

Cowen and Company, LLC

Piper Jaffray & Co.

As Representatives of the several Underwriters,

c/o Citigroup Global Markets Inc.

388 Greenwich Street

New York, New York 10013

c/o Cowen and Company, LLC

599 Lexington Avenue

New York, New York 10022

c/o Piper Jaffray & Co.

345 Park Avenue

New York, New York 9300

Ladies and Gentlemen:

Arsanis, Inc., a corporation organized under the laws of Delaware (the
“Issuer”), proposes to sell to the several underwriters named in Schedule I
hereto (the “Underwriters”), for whom Citigroup Global Markets Inc., Cowen and
Company, LLC and Piper Jaffray & Co. (the “Representatives”) are acting as
representatives, 4,000,000 shares of common stock, $0.001 par value per share
(“Common Stock”) of the Issuer (said shares to be issued and sold by the Issuer
being hereinafter called the “Underwritten Securities”). The Issuer also
proposes to grant to the Underwriters an option to purchase up to 600,000
additional shares of Common Stock to cover over-allotments, if any (the “Option
Securities;” the Option Securities, together with the Underwritten Securities,
hereinafter called the “Securities”). To the extent there are no additional
Underwriters listed on Schedule I other than you, the term Representatives as
used herein shall mean you, as Underwriters, and the terms Representatives and
Underwriters shall mean either the singular or plural as the context requires.
The offering and sale of the Securities contemplated by this Agreement is
referred to herein as the “Offering.”

 

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1. Representations and Warranties. The Issuer represents and warrants to, and
agrees with, each Underwriter as set forth below in this Section 1:

(a) The Issuer has prepared and filed with the Securities and Exchange
Commission (the “SEC”) a registration statement (file number 333-221050) on
Form S-1 including exhibits and financial statements and any prospectus
supplement relating to the Securities that is filed with the SEC pursuant to
Rule 424(b) under the Securities Act and deemed part of such registration
statement pursuant to Rule 430A under the Securities Act, as amended at the
Execution Time (as defined herein) and, in the event any post-effective
amendment thereto or any registration statement and any amendments thereto filed
pursuant to Rule 462(b) under the Securities Act (as defined herein) relating to
the Offering (the “Rule 462(b) Registration Statement”) becomes effective prior
to the Closing Date (as defined herein), shall also mean such registration
statement as so amended or such Rule 462(b) Registration Statement, as the case
may be (the “Registration Statement”), including the Preliminary Prospectus (as
defined herein), for registration under the Securities Act of 1933, as amended,
and the rules and regulations of the SEC promulgated thereunder (the “Securities
Act”) of the Offering. Such Registration Statement, including any amendments
thereto filed prior to the date and time that this agreement (the “Underwriting
Agreement”) is executed and delivered by the parties hereto (the “Execution
Time”), has become effective under the Securities Act. The Issuer may have filed
one or more amendments thereto, including a related preliminary prospectus
relating to the Securities which is used prior to the filing of the Prospectus
(the “Preliminary Prospectus”), each of which has previously been furnished to
you. The Issuer will file with the SEC a final prospectus relating to the
Securities in accordance with Rule 424(b) after the Execution Time (the
“Prospectus”). As filed, such Prospectus shall contain all information required
by the Securities Act and the rules thereunder and, except to the extent the
Representatives shall agree in writing to a modification, shall be in all
substantive respects in the form furnished to you prior to the Execution Time
or, to the extent not completed at the Execution Time, shall contain only such
specific additional information and other changes (beyond that contained in the
latest Preliminary Prospectus) as the Issuer has advised you, prior to the
Execution Time, will be included or made therein;

(b) On each date and time that the Registration Statement, any post-effective
amendment or amendments thereto and any Rule 462(b) Registration Statement
became or becomes effective (the “Effective Date”), the Registration Statement
did, and when the Prospectus is first filed in accordance with Rule 424(b) under
the Securities Act and on the Closing Date and on any date on which Option
Securities are purchased, if such date is not the Closing Date (a “settlement
date”), the Prospectus (and any supplement thereto) will, comply in all material
respects with the applicable requirements of the Securities Act and the rules
thereunder; on the Effective Date, at the Execution Time and on the Closing
Date, the Registration Statement did not and will not contain any untrue
statement of a material fact or omit to state any material fact required to be
stated therein or necessary in order to make the statements therein not
misleading; and on the date of any filing pursuant to Rule 424(b) and on the
Closing Date and any settlement date, the

 

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Prospectus (together with any supplement thereto) will not include any untrue
statement of a material fact or omit to state a material fact necessary in order
to make the statements therein, in the light of the circumstances under which
they were made, not misleading; provided, however, that the Issuer makes no
representations or warranties as to the information contained in or omitted from
the Registration Statement, or the Prospectus (or any supplement thereto) in
reliance upon and in conformity with information furnished in writing to the
Issuer by or on behalf of any Underwriter through the Representatives
specifically for inclusion in the Registration Statement or the Prospectus (or
any supplement thereto), it being understood and agreed that the only such
information furnished by any Underwriter consists of the information described
as such in Section 8 hereof;

(c) The “Disclosure Package” shall mean (i) the Preliminary Prospectus that is
generally distributed to investors and used to offer the Securities, (ii) any
issuer free writing prospectus, as defined in Rule 433 under the Securities Act
(the “Issuer Free Writing Prospectuses”), if any, identified in Schedule II
hereto and (iii) any other free writing prospectus, as defined in Rule 405 under
the Securities Act (a “Free Writing Prospectus”) that the parties hereto shall
hereafter expressly agree in writing to treat as part of the Disclosure Package.
The (i) Disclosure Package, (ii) each electronic road show, when taken together
as a whole with the Disclosure Package and (iii) any individual Written
Testing-the-Waters Communication (as defined herein), when taken together as a
whole with the Disclosure Package and the price to the public, the number of
Underwritten Securities and the number of Option Securities to be included on
the cover page of the Prospectus, does not contain any untrue statement of a
material fact or omit to state any material fact necessary in order to make the
statements therein, in the light of the circumstances under which they were
made, not misleading. The preceding sentence does not apply to statements in or
omissions from the Disclosure Package based upon and in conformity with written
information furnished to the Issuer by or on behalf of any Underwriter through
the Representatives specifically for use therein, it being understood and agreed
that the only such information furnished by or on behalf of any Underwriter
consists of the information described as such in Section 8 hereof;

(d) (i) At the time of filing the Registration Statement and (ii) as of the
Execution Time (with such date being used as the determination date for purposes
of this clause (ii)), the Issuer was not and is not an ineligible issuer, as
defined in Rule 405 under the Securities Act (an “Ineligible Issuer”), without
taking account of any determination by the SEC pursuant to Rule 405 that it is
not necessary that the Issuer be considered an Ineligible Issuer;

(e) From the time of initial confidential submission of the Registration
Statement to the SEC (or, if earlier, the first date on which the Issuer engaged
directly or through any person authorized to act on its behalf in any
Testing-the-Waters Communication) through the Execution Time, the Issuer has
been and is an “emerging growth company,” as defined in Section 2(a) of the
Securities Act (an “Emerging Growth Company”).

 

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“Testing-the-Waters Communication” means any oral or written communication with
potential investors undertaken in reliance on Section 5(d) of the Securities
Act;

(f) The Issuer (i) has not alone engaged in any Testing-the-Waters Communication
other than Testing-the-Waters Communications with the consent of the
Representatives with entities that are qualified institutional buyers within the
meaning of Rule 144A under the Securities Act or institutions that are
accredited investors within the meaning of Rule 501 under the Securities Act and
(ii) has not authorized anyone other than the Representatives to engage in
Testing-the-Waters Communications. The Issuer reconfirms that the
Representatives have been authorized to act on its behalf in undertaking
Testing-the-Waters Communications. The Issuer has not distributed any Written
Testing-the-Waters Communications other than those listed on Schedule III
hereto. “Written Testing-the-Waters Communication” means any Testing-the-Waters
Communication that is a written communication within the meaning of Rule 405
under the Securities Act;

(g) Each Issuer Free Writing Prospectus does not include any information that
conflicts with the information contained in the Registration Statement,
including any document incorporated by reference therein that has not been
superseded or modified. The foregoing sentence does not apply to statements in
or omissions from any Issuer Free Writing Prospectus based upon and in
conformity with written information furnished to the Issuer by or on behalf of
any Underwriter through the Representatives specifically for use therein, it
being understood and agreed that the only such information furnished by or on
behalf of any Underwriter consists of the information described as such in
Section 8 hereof;

(h) The interactive data in the eXtensible Business Reporting Language included
as an exhibit to the Registration Statement fairly presents the information
called for in all material respects and has been prepared in accordance with the
SEC’s rules and guidelines applicable thereto.  Each of the Issuer and its
subsidiaries has been duly incorporated and is validly existing as a corporation
in good standing under the laws of the jurisdiction in which it is chartered or
organized with full corporate power and authority to own or lease, as the case
may be, and to operate its properties and conduct its business as described in
the Disclosure Package and the Prospectus, and is duly qualified to do business
as a foreign corporation and is in good standing under the laws of each
jurisdiction which requires such qualification, except where the failure to be
so qualified or in good standing would not reasonably be expected to have a
material adverse effect (i) on the Issuer’s performance of this Underwriting
Agreement, (ii) the Issuer’s consummation of the Offering, or (iii) individually
or in the aggregate, on the condition (financial or otherwise), prospects,
earnings, business or properties of the Issuer and its subsidiaries, taken as a
whole, whether or not arising from transactions in the ordinary course of
business (clauses (i), (ii) or (iii), a “Material Adverse Effect”);

(i) All the outstanding shares of capital stock of each subsidiary have been
duly and validly authorized and issued and are fully paid and non-assessable,
and, except as

 

--------------------------------------------------------------------------------

 

otherwise set forth in the Disclosure Package and the Prospectus, all
outstanding shares of capital stock of the subsidiaries are owned by the Issuer
either directly or through wholly owned subsidiaries free and clear of any
perfected security interest or any other security interests, claims, liens or
encumbrances;

(j) There is no franchise, contract or other document of a character required to
be described in the Registration Statement or Prospectus, or to be filed as an
exhibit thereto, which is not described or filed as required (and the
Preliminary Prospectus contains in all material respects the same description of
the foregoing matters contained in the Prospectus); and the statements in the
Preliminary Prospectus and the Prospectus under the headings “Material U.S.
Federal Income and Estate Tax Considerations for Non-U.S. Holders of Common
Stock,” “Risk Factors—Risks Related to Our Intellectual Property,” “Risk
Factors—Risks Related to Regulatory Approval and Other Legal Compliance
Matters,” “Business—Intellectual Property” and “Business—Government Regulation
and Product Licensure,” insofar as such statements summarize legal matters,
agreements, documents or proceedings discussed therein, are accurate and fair
summaries of such legal matters, agreements, documents or proceedings;

(k) This Underwriting Agreement has been duly authorized, executed and delivered
by the Issuer;

(l) The Issuer is not, and immediately after giving effect to the Offering and
the application of the proceeds thereof as described in the Disclosure Package
and the Prospectus will not be, an “investment company” as defined in the
Investment Company Act of 1940, as amended;

(m) No consent, approval, authorization, filing with or order of any court or
governmental agency or body is required in connection with the transactions
contemplated herein, except such as have been obtained under the Securities Act
and such as may be required under the blue sky laws of any jurisdiction in
connection with the purchase and distribution of the Securities by the
Underwriters in the manner contemplated herein and in the Disclosure Package and
the Prospectus;

(n) Neither the issue and sale of the Securities nor the consummation of any
other of the transactions herein contemplated nor the fulfillment of the terms
hereof will conflict with, result in a breach or violation of, or imposition of
any lien, charge or encumbrance upon any property or assets of the Issuer or any
of its subsidiaries pursuant to, (i) the charter or by-laws of the Issuer or any
of its subsidiaries, (ii) the terms of any indenture, contract, lease, mortgage,
deed of trust, note agreement, loan agreement or other agreement, obligation,
condition, covenant or instrument to which the Issuer or any of its subsidiaries
is a party or bound or to which its or their property is subject, or (iii) any
statute, law, rule, regulation, judgment, order or decree applicable to the
Issuer or any of its subsidiaries of any court, regulatory body, administrative
agency, governmental body, arbitrator or other authority having jurisdiction
over the Issuer or any

 

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of its subsidiaries or any of its or their properties, except in the case of
clauses (ii) and (iii) as would not have a Material Adverse Effect;

(o) No holders of securities of the Issuer have rights to the registration of
such securities under the Registration Statement except for such registration
rights as have been effectively waived in connection with this Offering;

(p) The consolidated historical financial statements and schedules of the Issuer
and its consolidated subsidiary included in the Preliminary Prospectus, the
Prospectus and the Registration Statement present fairly in all material
respects the financial condition, results of operations and cash flows of the
Issuer as of the dates and for the periods indicated, comply as to form in all
material respects with the applicable accounting requirements of the Securities
Act and have been prepared in conformity with generally accepted accounting
principles in the United States applied on a consistent basis throughout the
periods involved (except as otherwise noted therein);  The selected financial
data set forth under the caption “Selected Financial Information” in the
Preliminary Prospectus, the Prospectus and Registration Statement fairly present
in all material respects, on the basis stated in the Preliminary Prospectus, the
Prospectus and the Registration Statement, the information included therein;

(q) No action, suit or proceeding by or before any court or governmental agency,
authority or body or any arbitrator involving the Issuer or any of its
subsidiaries or its or their property is pending or, to the best knowledge of
the Issuer, threatened that could reasonably be expected to have a Material
Adverse Effect, except as set forth in or contemplated in the Disclosure Package
and the Prospectus (exclusive of any supplement thereto);

(r) Each of the Issuer and each of its subsidiaries owns or leases all such
properties as are necessary to the conduct of its operations as presently
conducted, except for intellectual property which is separately addressed in
subsection (oo) below, and except as would not be reasonably be expected to have
a Material Adverse Effect;

(s) Neither the Issuer nor any subsidiary is in violation or default of (i) any
provision of its charter or bylaws, (ii) the terms of any indenture, contract,
lease, mortgage, deed of trust, note agreement, loan agreement or other
agreement, obligation, condition, covenant or instrument to which it is a party
or bound or to which its property is subject, or (iii) any statute, law, rule,
regulation, judgment, order or decree of any court, regulatory body,
administrative agency, governmental body, arbitrator or other authority having
jurisdiction over the Issuer or such subsidiary or any of its properties, as
applicable except in the case of clauses (ii) and (iii), for such breach,
violation or default as would not, individually or in the aggregate, reasonably
be expected to have a Material Adverse Effect;

(t) PricewaterhouseCoopers LLP, who have certified certain financial statements
of the Issuer and its consolidated subsidiary and delivered their report with
respect to the

 

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audited consolidated financial statements and schedules included in the
Disclosure Package and the Prospectus, are independent public accountants with
respect to the Issuer within the meaning of the Securities Act and the
applicable published rules and regulations thereunder;

(u) There are no transfer taxes or other similar fees or charges under Federal
law or the laws of any state, or any political subdivision thereof, required to
be paid in connection with the execution and delivery of this Underwriting
Agreement or the issuance by the Issuer or sale by the Issuer of the Securities;

(v) The Issuer has filed all tax returns that are required to be filed or has
requested extensions thereof (except in any case in which the failure so to file
would not reasonably be expected to have a Material Adverse Effect) and has paid
all taxes required to be paid by it and any other assessment, fine or penalty
levied against it, to the extent that any of the foregoing is due and payable,
except for any such assessment, fine or penalty that is currently being
contested in good faith or as would not reasonably be expected to have a
Material Adverse Effect;

(w) No labor problem or dispute with the employees of the Issuer or any of its
subsidiaries exists or is threatened or, to the Issuer’s knowledge, imminent,
and the Issuer is not aware of any existing or imminent labor disturbance by the
employees of any of its or its subsidiaries’ principal suppliers, contractors or
customers, that could have a Material Adverse Effect;

(x) The Issuer and each of its subsidiaries are insured by insurers of
recognized financial responsibility against such losses and risks and in such
amounts as the Issuer reasonably believes are prudent and customary in the
businesses in which the Issuer and its subsidiaries are engaged; all policies of
insurance insuring the Issuer or any of its subsidiaries or their respective
businesses, assets, employees, officers and directors are in full force and
effect; the Issuer and its subsidiaries are in compliance with the terms of such
policies and instruments in all material respects; and there are no claims by
the Issuer or any of its subsidiaries under any such policy or instrument as to
which any insurance company is denying liability or defending under a
reservation of rights clause; neither the Issuer nor any such subsidiary has
been refused any insurance coverage sought or applied for; and neither the
Issuer nor any such subsidiary has any reason to believe that it will not be
able to renew its existing insurance coverage as and when such coverage expires
or to obtain similar coverage from similar insurers as may be necessary to
continue its business at a cost that would not reasonably be expected to have a
Material Adverse Effect;

(y) The Issuer and its subsidiaries possess all licenses, certificates, permits
and other authorizations required to be issued by all applicable authorities
necessary to conduct their respective businesses, except where the failure to
possess such license, certificate, permit and other authorization would not,
individually or in the aggregate, reasonably be expected to have a Material
Adverse Effect, and neither the Issuer nor any

 

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such subsidiary has received any notice of proceedings relating to the
revocation or modification of any such certificate, authorization or permit
which, singly or in the aggregate, if the subject of an unfavorable decision,
ruling or finding, would individually or in the aggregate, reasonably be
expected to have a Material Adverse Effect;

(z) The Issuer maintains a system of internal accounting controls designed to
provide reasonable assurance that (i) transactions are executed in accordance
with management’s general or specific authorizations; (ii) transactions are
recorded as necessary to permit preparation of financial statements in
conformity with generally accepted accounting principles in the United States
and to maintain asset accountability; (iii) access to assets is permitted only
in accordance with management’s general or specific authorization; (iv) the
recorded accountability for assets is compared with the existing assets at
reasonable intervals and appropriate action is taken with respect to any
differences; and (v) the interactive data in eXtensible Business Reporting
Language included or incorporated by reference in the Registration Statement,
the Preliminary Prospectus and the Prospectus is in compliance with the SEC’s
published rules, regulations and guidelines applicable thereto. The Issuer’s
internal controls over financial reporting are effective and the Issuer is not
aware of any material weakness in its internal controls over financial
reporting;

(aa) The Issuer maintains “disclosure controls and procedures” (as such term is
defined in Rule 13a-15(e) under the Securities and Exchange Act 1934, as amended
and the rules and regulations of the SEC promulgated thereunder (the “Exchange
Act”); such disclosure controls and procedures are effective at the reasonable
assurance level;

(bb) The Issuer has not taken, directly or indirectly, without giving effect to
activities by the Underwriters, any action designed to or that would constitute
or that would reasonably be expected to cause or result in, under the Exchange
Act or otherwise, stabilization or manipulation of the price of any security of
the Issuer to facilitate the sale or resale of the Securities;

(cc) The Issuer and its subsidiaries are (i) in compliance with any and all
applicable foreign, federal, state and local laws and regulations relating to
the protection of human health and safety, the environment or hazardous or toxic
substances or wastes, pollutants or contaminants (“Environmental Laws”), (ii)
have received and are in compliance with all permits, licenses or other
approvals required of them under applicable Environmental Laws to conduct their
respective businesses and (iii) have not received notice of any actual or
potential liability under any environmental law, except where such
non-compliance with Environmental Laws, failure to receive required permits,
licenses or other approvals, or liability would not, individually or in the
aggregate, reasonably be expected to have a Material Adverse Effect. Except as
set forth in the Disclosure Package and the Prospectus, neither the Issuer nor
any of the subsidiaries has been named as a “potentially responsible party”
under the Comprehensive Environmental Response, Compensation, and Liability Act
of 1980, as amended;

 

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(dd) None of the following events has occurred or exists:  (i) a failure to
fulfill the obligations, if any, under the minimum funding standards of Section
302 of the United States Employee Retirement Income Security Act of 1974, as
amended (“ERISA”), and the regulations and published interpretations thereunder
with respect to a Plan (as defined herein), determined without regard to any
waiver of such obligations or extension of any amortization period; (ii) an
audit or investigation by the Internal Revenue Service, the U.S. Department of
Labor, the Pension Benefit Guaranty Corporation or any other federal or state
governmental agency or any foreign regulatory agency with respect to the
employment or compensation of employees by any of the Issuer or any of its
subsidiaries that would reasonably be expected to have a Material Adverse
Effect; (iii) any breach of any contractual obligation, or any violation of law
or applicable qualification standards, with respect to the employment or
compensation of employees by the Issuer or any of its subsidiaries that would
reasonably be expected to have a Material Adverse Effect.  None of the following
events has occurred or is reasonably likely to occur: (i) a material increase in
the aggregate amount of contributions required to be made to all Plans in the
current fiscal year of the Issuer and its subsidiaries compared to the amount of
such contributions made in the most recently completed fiscal year of the Issuer
and its subsidiaries; (ii) a material increase in the “accumulated
post-retirement benefit obligations” (within the meaning of Statement of
Financial Accounting Standards 106) of the Issuer and its subsidiaries compared
to the amount of such obligations in the most recently completed fiscal year of
the Issuer and its subsidiaries; (iii) any event or condition giving rise to a
liability under Title IV of ERISA that would reasonably be expected to have a
Material Adverse Effect; or (iv) the filing of a claim by one or more employees
or former employees of the Issuer or any of its subsidiaries related to their
employment that would reasonably be expected to have a Material Adverse
Effect.  For purposes of this paragraph, the term “Plan” means a plan (within
the meaning of Section 3(3) of ERISA) subject to Title IV of ERISA with respect
to which the Issuer or any of its subsidiaries may have any liability;

(ee) There is and has been no failure on the part of the Issuer and any of the
Issuer’s directors or officers, in their capacities as such, to comply with any
provision of the Sarbanes-Oxley Act of 2002 and the rules and regulations
promulgated in connection therewith (the “Sarbanes-Oxley Act”), that are in
effect and with which the Issuer is required to comply as of the Effective Date
including Section 402 relating to loans;

(ff) Neither the Issuer nor any of its subsidiaries nor, to the knowledge of the
Issuer, any director, officer, agent, employee, affiliate or other person acting
on behalf of the Issuer or any of its subsidiaries is aware of or has taken any
action, directly or indirectly, that would result in a violation or a sanction
for violation by such persons of the Foreign Corrupt Practices Act of 1977 or
the U.K. Bribery Act 2010, each as may be amended, or similar law of any other
relevant jurisdiction, or the rules or regulations thereunder; and the Issuer
and its subsidiaries have instituted and maintain policies and procedures to
ensure compliance therewith.  No part of the proceeds of the Offering will be
used, directly or indirectly, in violation of the Foreign Corrupt Practices Act
of 1977

 

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or the U.K. Bribery Act 2010, each as may be amended, or similar law of any
other relevant jurisdiction, or the rules or regulations thereunder;

(gg) The operations of the Issuer and its subsidiaries are and have been
conducted at all times in compliance with applicable financial recordkeeping and
reporting requirements and the money laundering statutes and the rules and
regulations thereunder and any related or similar rules, regulations or
guidelines, issued, administered or enforced by any governmental agency
(collectively, the “Money Laundering Laws”) and no action, suit or proceeding by
or before any court or governmental agency, authority or body or any arbitrator
involving the Issuer or any of its subsidiaries with respect to the Money
Laundering Laws is pending or, to the knowledge of the Issuer, threatened;

(hh) Neither the Issuer nor any of its subsidiaries nor, to the knowledge of the
Issuer, any director, officer, agent, employee or affiliate of the Issuer or any
of its subsidiaries (i) is, or is controlled or 50% or more owned in the
aggregate by or is acting on behalf of, one or more individuals or entities that
are currently the subject of any sanctions administered or enforced by the
United States (including any administered or enforced by the Office of Foreign
Assets Control of the U.S. Department of the Treasury, the U.S. Department of
State or the Bureau of Industry and Security of the U.S. Department of
Commerce), the United Nations Security Council, the European Union, a member
state of the European Union (including sanctions administered or enforced by Her
Majesty’s Treasury of the United Kingdom) or other relevant sanctions authority
(collectively, “Sanctions” and such persons, “Sanctioned Persons” and each such
person, a “Sanctioned Person”), (ii) is located, organized or resident in a
country or territory that is, or whose government is, the subject of Sanctions
that broadly prohibit dealings with that country or territory (collectively,
“Sanctioned Countries” and each, a “Sanctioned Country”) or (iii)  will,
directly or indirectly, use the proceeds of this Offering, or lend, contribute
or otherwise make available such proceeds to any subsidiary, joint venture
partner or other individual or entity in any manner that would result in a
violation of any Sanctions by, or could result in the imposition of Sanctions
against, any individual or entity (including any individual or entity
participating in the Offering, whether as underwriter, advisor, investor or
otherwise);

(ii) Neither the Issuer nor any of its subsidiaries has engaged in any dealings
or transactions with or for the benefit of a Sanctioned Person, or with or in a
Sanctioned Country, in the preceding 3 years, nor does the Issuer or any of its
subsidiaries have any plans to engage in dealings or transactions with or for
the benefit of a Sanctioned Person, or with or in a Sanctioned Country;

(jj) The Issuer’s only subsidiary at the Effective Date is Arsanis Biosciences
GmbH.

(kk) Except as described in the Registration Statement, the Disclosure Package
and the Prospectus, as applicable, the Issuer (i) is and at all times has been
in compliance in all material respects with all statutes, rules and regulations
applicable to the ownership,

 

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testing, development, manufacture, packaging, processing, use, distribution,
marketing, advertising, labeling, promotion, sale, offer for sale, storage,
import, export or disposal of any product manufactured or distributed by the
Issuer including, without limitation the Federal Food, Drug and Cosmetic Act (21
U.S.C. §301 et seq.), the federal Anti-Kickback Statute (42 U.S.C.
§1320a-7b(b)), the Health Insurance Portability and Accountability Act of 1996,
as amended by the Health Information Technology for Economic and Clinical Health
Act of 2009, and the Patient Protection and Affordable Care Act of 2010, as
amended by the Health Care and Education Affordability Reconciliation Act of
2010, the regulations promulgated pursuant to such laws, and any successor
government programs and comparable state laws, regulations relating to Good
Clinical Practices and Good Laboratory Practices and all other local, state,
federal, national, supranational and foreign laws, manual provisions, policies
and administrative guidance relating to the regulation of the Company
(collectively, the “Applicable Laws”); (ii) has not received any written notice
from any court or arbitrator or governmental or regulatory authority or third
party alleging or asserting material noncompliance with any Applicable Laws or
any licenses, exemptions, certificates, approvals, clearances, authorizations,
permits, registrations and supplements or amendments thereto required by any
such Applicable Laws (“Authorizations”); (iii) possesses all Authorizations and
such Authorizations are valid and in full force and effect and are not in
material violation of any term of any such Authorizations; (iv) has not received
written notice of any claim, action, suit, proceeding, hearing, enforcement,
investigation, arbitration or other action from any court or arbitrator or
governmental or regulatory authority or third party alleging that any product
operation or activity is in violation of any Applicable Laws or Authorizations
nor, to Issuer’s knowledge, is any such claim, action, suit, proceeding,
hearing, enforcement, investigation, arbitration or other action threatened; (v)
has  received any written notice that any court or arbitrator or governmental or
regulatory authority has taken, is taking or intends to take, action to limit,
suspend, materially modify or revoke any Authorizations nor, to Issuer’s
knowledge is any such limitation, suspension, modification or revocation
threatened; (vi) has filed, obtained, maintained or submitted all material
reports, documents, forms, notices, applications, records, claims, submissions
and supplements or amendments as required by any Applicable Laws or
Authorizations and that all such reports, documents, forms, notices,
applications, records, claims, submissions and supplements or amendments were
complete and accurate in all material respects on the date filed (or were
corrected or supplemented by a subsequent submission);  and (vii) is not a party
to any corporate integrity agreements, monitoring agreements, consent decrees,
settlement orders, or similar agreements with or imposed by any governmental or
regulatory authority.

(ll) The clinical and pre-clinical trials conducted by or on behalf of or
sponsored by the Issuer, or in which the Issuer has participated, that are
described in the Registration Statement, the Disclosure Package and the
Prospectus or the results of which are referred to in the Registration
Statement, the Disclosure Package and the Prospectus, as applicable, and are
intended to be submitted to Regulatory Authorities as a basis for product
approval, were and, if still pending, are being conducted in all material
respects in accordance with standard medical and scientific research procedures
and all applicable

 

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statutes, rules and regulations of the United States Food and Drug
Administration and comparable drug regulatory agencies outside of the United
States to which they are subject (collectively, the “Regulatory Authorities”),
including, without limitation, 21 C.F.R. Parts 50, 54, 56, 58, and 312, and
current Good Clinical Practices and Good Laboratory Practices; the descriptions
in the Registration Statement, the Disclosure Package or the Prospectus of the
results of such studies and trials are accurate and complete in all material
respects and fairly present the data derived from such trials; the Issuer has no
knowledge of any other trials the results of which are inconsistent with or
otherwise call into question the results described or referred to in the
Registration Statement, Disclosure Package and the Prospectus; the Company has
not received any written notices, correspondence or other communication from the
Regulatory Authorities or any governmental authority which could lead to the
termination or suspension of any clinical or pre-clinical trials that are
described in the Registration Statement, the Disclosure Package and the
Prospectus or the results of which are referred to in the Registration
Statement, Disclosure Package or the Prospectus, and to Issuer’s knowledge there
are no reasonable grounds for same.

(mm) Except as set forth in the Disclosure Package and the Prospectus, the
Issuer and its subsidiaries own, possess, license or have other rights to use,
on reasonable terms, all patents, patent applications, trade and service marks,
trade and service mark registrations, trade names, copyrights, licenses,
inventions, trade secrets, technology, know-how and other intellectual property
necessary for the conduct of the Issuer’s business as now conducted or as
proposed in the Disclosure Package and Prospectus to be conducted (collectively,
the “Intellectual Property”).  Except as set forth in the Disclosure Package and
the Prospectus under the caption “Business—Intellectual Property,” (a) there are
no rights owned by third parties in any such Intellectual Property; (b) to the
Issuer’s knowledge, there is no material infringement by third parties of any
such Intellectual Property; (c) there is no pending or, to the Issuer’s
knowledge, threatened action, suit, proceeding or claim by others challenging
the Issuer’s rights in or to any such Intellectual Property, and, the Issuer is
unaware of any facts which would form a reasonable basis for any such claim; (d)
there is no pending or threatened action, suit, proceeding or claim by others
challenging the validity or scope of any such Intellectual Property, and the
Issuer is unaware of any facts which would form a reasonable basis for any such
claim; (e) there is no pending or, to the Issuer’s knowledge,  threatened
action, suit, proceeding or claim by others that the Issuer infringes or
otherwise violates any patent, trademark, copyright, trade secret or other
proprietary rights of others, and, the Issuer is unaware of any other fact which
would form a reasonable basis for any such claim; and (f) to the Issuer’s
knowledge, there is no prior art of which the Issuer is aware that may render
any U.S. patent held by the Issuer invalid or any U.S. patent application held
by the Issuer un-patentable which has not been disclosed to the U.S. Patent and
Trademark Office;

(nn) Except as disclosed in the Registration Statement, the Disclosure Package
and the Prospectus, the Issuer (i) does not have any material lending or other
relationship with any bank or lending affiliate of Citigroup Global Markets
Holdings Inc. and (ii) does

 

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not intend to use any of the proceeds from the sale of the Securities hereunder
to repay any outstanding debt owed to any affiliate of Citigroup Global Markets
Holdings Inc.; and

(oo) Any certificate signed by any officer of the Issuer and delivered to the
Representatives or counsel for the Underwriters in connection with the Offering
of the Securities shall be deemed a representation and warranty by the Issuer,
as to matters covered thereby, to each Underwriter.

2. Purchase and Sale.  

(a) Subject to the terms and conditions and in reliance upon the representations
and warranties herein set forth, the Issuer agrees to sell to each Underwriter,
and each Underwriter agrees, severally and not jointly, to purchase from the
Issuer, at a purchase price of $9.30 per share, the amount of the Underwritten
Securities set forth opposite such Underwriter’s name in Schedule I hereto; and

(b) Subject to the terms and conditions and in reliance upon the representations
and warranties herein set forth, the Issuer hereby grants an option to the
several Underwriters to purchase, severally and not jointly, up to 600,000
Option Securities at the same purchase price per share as the Underwriters shall
pay for the Underwritten Securities, less an amount per share equal to any
dividends or distributions declared by the Issuer and payable on the
Underwritten Securities but not payable on the Option Securities. Said option
may be exercised only to cover over-allotments in the sale of the Underwritten
Securities by the Underwriters. Said option may be exercised in whole or in part
at any time on or before the 30th day after the date of the Prospectus upon
written or telegraphic notice by the Representatives to the Issuer setting forth
the number of shares of the Option Securities as to which the several
Underwriters are exercising the option and the settlement date.  The number of
Option Securities to be purchased by each Underwriter shall be the same
percentage of the total number of shares of the Option Securities to be
purchased by the several Underwriters as such Underwriter is purchasing of the
Underwritten Securities, subject to such adjustments as you in your absolute
discretion shall make to eliminate any fractional shares.

3. Delivery and Payment.  Delivery of and payment for the Underwritten
Securities and the Option Securities (if the option provided for in Section 2(b)
hereof shall have been exercised on or before the third Business Day (as defined
herein) immediately preceding the Closing Date) shall be made at 10:00 AM,
Eastern Standard Time, on November 20, 2017, or at such time on such later date
not more than three Business Days after the foregoing date as the
Representatives shall designate, which date and time may be postponed by
agreement between the Representatives and the Issuer or as provided in Section 9
hereof (such date and time of delivery and payment for the Securities being
herein called the “Closing Date”).  For purposes herein, “Business Day” shall
mean any day other than a Saturday, a Sunday or a legal holiday or a day on
which banking institutions or trust companies are authorized or obligated by law
to close in New York, New York. Delivery of the Securities shall be made to the
Representatives

 

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for the respective accounts of the several Underwriters against payment by the
several Underwriters through the Representatives of the purchase price thereof
to or upon the order of the Issuer by wire transfer payable in same-day funds to
an account specified by the Issuer.  Delivery of the Underwritten Securities and
the Option Securities shall be made through the facilities of The Depository
Trust Company unless the Representatives shall otherwise instruct.

If the option provided for in Section 2(b) hereof is exercised after the third
Business Day immediately preceding the Closing Date, the Issuer will deliver the
Option Securities (at the expense of the Issuer) to the Representatives, at 620
Eighth Avenue, New York, New York, 10018 on the date specified by the
Representatives (which shall be within three Business Days after exercise of
said option) for the respective accounts of the several Underwriters, against
payment by the several Underwriters through the Representatives of the purchase
price thereof to or upon the order of the Issuer by wire transfer payable in
same-day funds to an account specified by the Issuer.  If settlement for the
Option Securities occurs after the Closing Date, the Issuer will deliver to the
Representatives on the settlement date for the Option Securities, and the
obligation of the Underwriters to purchase the Option Securities shall be
conditioned upon receipt of, supplemental opinions, certificates and letters
confirming as of such date the opinions, certificates and letters delivered on
the Closing Date pursuant to Section 6 hereof.

4. Offering by Underwriters.  It is understood that the several Underwriters
propose to offer the Securities for sale to the public as set forth in the
Prospectus.

5. Agreements.  The Issuer agrees with the several Underwriters that:

(a) Prior to the termination of the Offering, the Issuer will not file any
amendment of the Registration Statement or supplement to the Prospectus or any
Rule 462(b) Registration Statement unless the Issuer has furnished you a copy
for your review prior to filing and will not file any such proposed amendment or
supplement to which you reasonably object. The Issuer will cause the Prospectus
and any supplement thereto to be filed in a form approved by the Representatives
with the SEC pursuant to the applicable paragraph of Rule 424(b) under the
Securities Act within the time period prescribed and will provide evidence
satisfactory to the Representatives of such timely filing.  The Issuer will
promptly advise the Representatives (i) when the Prospectus, and any supplement
thereto, shall have been filed (if required) with the SEC pursuant to
Rule 424(b) or when any Rule 462(b) Registration Statement shall have been filed
with the SEC, (ii) when, prior to termination of the Offering, any amendment to
the Registration Statement shall have been filed or become effective, (iii) of
any request by the SEC or its staff for any amendment of the Registration
Statement, or any Rule 462(b) Registration Statement, or for any supplement to
the Prospectus or for any additional information, (iv) of the issuance by the
SEC of any stop order suspending the effectiveness of the Registration Statement
or of any notice objecting to its use or the institution or threatening of any
proceeding for that purpose and (v) of the receipt by the Issuer of any
notification with respect to the suspension of the qualification of the
Securities for sale in any jurisdiction or the institution or threatening of any
proceeding for such purpose.  The Issuer will use

 

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its reasonable best efforts to prevent the issuance of any such stop order or
the occurrence of any such suspension or objection to the use of the
Registration Statement and, upon such issuance, occurrence or notice of
objection, to obtain as soon as possible the withdrawal of such stop order or
relief from such occurrence or objection, including, if necessary, by filing an
amendment to the Registration Statement or a new registration statement and
using its reasonable best efforts to have such amendment or new registration
statement declared effective as soon as practicable;

(b) If, at any time prior to the filing of the Prospectus pursuant to Rule
424(b) under the Securities Act, any event occurs as a result of which the
Disclosure Package would include any untrue statement of a material fact or omit
to state any material fact necessary in order to make the statements therein in
the light of the circumstances under which they were made at such time not
misleading, the Issuer will (i) notify promptly the Representatives so that any
use of the Disclosure Package may cease until it is amended or supplemented;
(ii) amend or supplement the Disclosure Package to correct such statement or
omission; and (iii) supply any amendment or supplement to you in such quantities
as you may reasonably request;  

(c) If, at any time when a prospectus relating to the Securities is required to
be delivered under the Securities Act (including in circumstances where such
requirement may be satisfied pursuant to Rule 172), any event occurs as a result
of which the Prospectus as then supplemented would include any untrue statement
of a material fact or omit to state any material fact necessary in order to make
the statements therein in the light of the circumstances under which they were
made or the circumstances then prevailing not misleading, or if it shall be
necessary to amend the Registration Statement or supplement the Prospectus to
comply with the Securities Act or the rules thereunder, the Issuer promptly will
(i) notify the Representatives of any such event; (ii) prepare and file with the
SEC, subject to the second sentence of paragraph (a) of this Section 5, an
amendment or supplement which will correct such statement or omission or effect
such compliance; and (iii) supply any supplemented Prospectus to you in such
quantities as you may reasonably request;

(d) As soon as practicable, the Issuer will make generally available to its
security holders and to the Representatives an earnings statement or statements
of the Issuer which will satisfy the provisions of Section 11(a) of the
Securities Act and of Rule 158 under the Securities Act;

(e) The Issuer will furnish to the Representatives and counsel for the
Underwriters, without charge, signed copies of the Registration Statement
(including exhibits thereto) and to each other Underwriter a copy of the
Registration Statement (without exhibits thereto) and, so long as delivery of a
prospectus by an Underwriter or dealer may be required by the Securities Act
(including in circumstances where such requirement may be satisfied pursuant to
Rule 172), as many copies of each Preliminary Prospectus, the Prospectus and
each Issuer Free Writing Prospectus and any supplement

 

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thereto as the Representatives may reasonably request.   The Issuer will pay the
expenses of printing or other production of all documents relating to the
Offering;

(f) The Issuer will arrange, if necessary, for the qualification of the
Securities for sale under the laws of such jurisdictions as the Representatives
may reasonably designate and will use its reasonable best efforts to maintain
such qualifications in effect so long as required for the distribution of the
Securities; provided that in no event shall the Issuer be (i) obligated to
qualify to do business in any jurisdiction where it is not now so qualified,
(ii) obligated to take any action that would subject it to service of process in
suits, other than those arising out of the Offering, in any jurisdiction where
it is not now so subject or (iii) subject itself to taxation in any jurisdiction
in which it is not otherwise subject to taxation on the date hereof.

(g) The Issuer will not, without the prior written consent of the Citigroup
Global Markets Inc. and Cowen and Company, LLC, offer, sell, contract to sell,
pledge, or otherwise dispose of, (or enter into any transaction which is
designed to, or might reasonably be expected to, result in the disposition
(whether by actual disposition or effective economic disposition due to cash
settlement or otherwise) by the Issuer or any affiliate of the Issuer or any
person in privity with the Issuer or any affiliate of the Issuer) directly or
indirectly, including the filing (or participation in the filing) of a
registration statement (other than a registration statement on Form S-8) with
the SEC in respect of, or establish or increase a put equivalent position or
liquidate or decrease a call equivalent position within the meaning of Section
16 of the Exchange Act, any other shares of Common Stock or any securities
convertible into, or exercisable, or exchangeable for, shares of Common Stock;
or publicly announce an intention to effect any such transaction, for a period
of 180 days after the date of the Underwriting Agreement, provided, however,
that (i) the Issuer may issue and sell Common Stock or any securities
convertible into, or exercisable, or exchangeable for, shares of Common Stock,
pursuant to any employee stock option plan, incentive plan, employee stock
purchase plan, stock ownership plan or dividend reinvestment plan of the Issuer
in effect at the Execution Time or disclosed in the Prospectus, (ii) and the
Issuer may issue Common Stock issuable upon the conversion of securities or the
exercise of warrants outstanding at the Execution Time, (iii) offer, issue and
sell shares of Common Stock, or any securities convertible into or exercisable
or exchangeable for Common Stock, in connection with any acquisition or
strategic investment (including any joint venture, strategic alliance or
partnership, (iv) issue, offer or sell any shares of Common Stock or securities
convertible into or exercisable or exchangeable for shares of Common Stock, on
an arm’s-length basis, to unaffiliated financial institutions or lessors
pursuant to a commercial agreement, equipment financing transaction or
commercial property lease transaction and (v) issue, offer or sell any shares of
Common Stock or securities convertible into or exercisable or exchangeable for
shares of Common Stock, on an arm’s-length basis, to unaffiliated collaborators,
vendors, manufacturers, lessors, distributors, customers or other similar
parties pursuant to a collaboration, licensing agreement, strategic alliance,
lease, manufacturing or distribution arrangement or similar transaction;
provided, further, that (x) the aggregate number of shares of Common Stock
issued or issuable in accordance

 

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with clauses (iii), (iv) or (v) of this paragraph do not exceed 10% of the
number of shares of Common Stock outstanding immediately after the issuance and
sale of the Securities and (y) each recipient of any such shares or other
securities agrees to restrictions on the resale of securities that are
consistent with the provisions set forth in the lock-up letter described in
Section 6(j) for the remainder of the 180-day restricted period;

(h) If Citigroup Global Markets Inc. and Cowen and Company, LLC, in their sole
discretion, agree to release or waive the restrictions set forth in a lock-up
letter described in Section 6(j) hereof for an officer or director of the Issuer
and provides the Issuer with notice of the impending release or waiver at least
three Business Days before the effective date of the release or waiver, the
Issuer agrees to announce the impending release or waiver by a press release
substantially in the form of Exhibit D hereto through a major news service at
least two Business Days before the effective date of the release or waiver;

(i) The Issuer will not take, directly or indirectly, without giving effect to
the activities by the Underwriters, any action designed to or that would
constitute or that would reasonably be expected to cause or result in, under the
Exchange Act or otherwise, stabilization or manipulation of the price of any
security of the Issuer to facilitate the sale or resale of the Securities;

(j) The Issuer agrees to pay the costs and expenses relating to the following
matters:  (i) the preparation, printing or reproduction and filing with the SEC
of the Registration Statement (including financial statements and exhibits
thereto), each Preliminary Prospectus, the Prospectus and each Issuer Free
Writing Prospectus, and each amendment or supplement to any of them; (ii) the
printing (or reproduction) and delivery (including postage, air freight charges
and charges for counting and packaging) of such copies of the Registration
Statement, each Preliminary Prospectus, the Prospectus and each Issuer Free
Writing Prospectus, and all amendments or supplements to any of them, as may, in
each case, be reasonably requested for use in connection with the Offering;
(iii) the preparation, printing, authentication, issuance and delivery of
certificates for the Securities, including any stamp or transfer taxes in
connection with the original issuance and sale of the Securities; (iv) the
printing (or reproduction) and delivery of this Underwriting Agreement, any blue
sky memorandum and all other agreements or documents printed (or reproduced) and
delivered in connection with the Offering; (v) the registration of the
Securities under the Exchange Act and the listing of the Securities on the
NASDAQ Global Market; (vi) any registration or qualification of the Securities
for offer and sale under the securities or blue sky laws of the several states
(including filing fees and the reasonable fees and expenses of counsel for the
Underwriters relating to such registration and qualification); (vii) any filings
required to be made with the Financial Industry Regulatory Authority, Inc.
(“FINRA”) (including filing fees and the reasonable fees and expenses of counsel
for the Underwriters relating to such filings), with such fees and expenses of
counsel contained in clauses (vi) and (vii) not to exceed $30,000 in the
aggregate); (viii) the transportation and other expenses incurred by or on
behalf of Issuer representatives in connection with presentations to

 

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prospective purchasers of the Securities; provided that in relation to such
presentations, if the Issuer and the Underwriters agree that a private or
chartered aircraft should be used for such presentations, the Issuer will only
be responsible for 50% of the costs and expense associated with such aircraft
and the Underwriters shall be responsible for the balance, (ix) the fees and
expenses of the Issuer’s accountants and the fees and expenses of counsel
(including local and special counsel) for the Issuer; and (x) all other costs
and expenses incident to the performance by the Issuer of its obligations
hereunder;

(k) The Issuer agrees that, unless it has or shall have obtained the prior
written consent of the Representatives, and each Underwriter, severally and not
jointly, agrees with the Issuer that, unless it has or shall have obtained, as
the case may be, the prior written consent of the Issuer, it has not made and
will not make any offer relating to the Securities that would constitute an
Issuer Free Writing Prospectus or that would otherwise constitute a Free Writing
Prospectus required to be filed by the Issuer with the SEC or retained by the
Issuer under Rule 433 under the Securities Act; provided that the prior written
consent of the parties hereto shall be deemed to have been given in respect of
the Free Writing Prospectuses included in Schedule II hereto and any electronic
road show.  Any such free writing prospectus consented to by the Representatives
or the Issuer is hereinafter referred to as a “Permitted Free Writing
Prospectus.”  The Issuer agrees that (x) it has treated and will treat, as the
case may be, each Permitted Free Writing Prospectus as an Issuer Free Writing
Prospectus and (y) it has complied and will comply, as the case may be, with the
requirements of Rules 164 and 433 applicable to any Permitted Free Writing
Prospectus, including in respect of timely filing with the SEC, legending and
record keeping;

(l) The Issuer will notify promptly the Representatives if the Issuer ceases to
be an Emerging Growth Company at any time prior to the later of (a) completion
of the distribution of the Securities within the meaning of the Securities Act
and (b) completion of the 180-day restricted period referred to in Section 5(g)
hereof; and

(m) If at any time following the distribution of any Written Testing-the-Waters
Communication, any event occurs as a result of which such Written
Testing-the-Waters Communication would include any untrue statement of a
material fact or  omit to state any material fact necessary in order to make the
statements therein in the light of the circumstances under which they were made
at such time not misleading, the Issuer will (i) notify promptly the
Representatives so that use of the Written Testing-the-Waters Communication may
cease until it is amended or supplemented; (ii) amend or supplement the Written
Testing-the-Waters Communication to correct such statement or omission; and
(iii) supply any amendment or supplement to the Representatives in such
quantities as may be reasonably requested.

6. Conditions to the Obligations of the Underwriters.  The obligations of the
Underwriters to purchase the Underwritten Securities and the Option Securities,
as the case may be, shall be subject to the accuracy of the representations and
warranties on the part of the Issuer contained herein as of the Execution Time,
the Closing Date and any settlement date pursuant to

 

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Section 3 hereof, to the accuracy of the statements of the Issuer made in any
certificates pursuant to the provisions hereof, to the performance by the Issuer
of its obligations hereunder and to the following additional conditions:

(a) The Prospectus, and any supplement thereto, have been filed in the manner
and within the time period required by Rule 424(b) under the Securities Act; any
material required to be filed by the Issuer pursuant to Rule 433(d) under the
Securities Act shall have been filed with the SEC within the applicable time
periods prescribed for such filings by Rule 433; and no stop order suspending
the effectiveness of the Registration Statement or any notice objecting to its
use shall have been issued and no proceedings for that purpose shall have been
instituted or threatened.

(b) The Issuer shall have requested and caused Wilmer Cutler Pickering Hale and
Dorr LLP, counsel for the Issuer, to have furnished to the Representatives their
opinion, dated the Closing Date and addressed to the Representatives,
substantially in the form attached hereto as Exhibit A.

(c) The Issuer shall have requested and caused Redl Life Science Patent
Attorneys, intellectual property counsel for the Issuer, to have furnished to
the Representatives their opinion, dated the Closing Date and addressed to the
Representatives, substantially in the form attached hereto as Exhibit B.

(d) The Representatives shall have received from Goodwin Procter LLP, counsel
for the Underwriters, such opinion or opinions, dated the Closing Date and
addressed to the Representatives, with respect to the issuance and sale of the
Securities, the Registration Statement, the Disclosure Package, the Prospectus
(together with any supplement thereto) and other related matters as the
Representatives may reasonably require, and the Issuer shall have furnished to
such counsel such documents as they may reasonably request for the purpose of
enabling them to pass upon such matters;

(e) The Issuer shall have furnished to the Representatives a certificate of the
Issuer, signed by the Chief Executive Officer and the Chief Operating Officer
and Chief Financial Officer of the Issuer, dated the Closing Date, to the effect
that the signers of such certificate have carefully examined the Registration
Statement, the Disclosure Package, the Prospectus and any amendment or
supplement thereto, as well as each electronic road show used in connection with
the Offering, and this Underwriting Agreement and that:

(i) the representations and warranties of the Issuer in this Underwriting
Agreement are true and correct on and as of the Closing Date with the same
effect as if made on the Closing Date and the Issuer has complied with all the
agreements and satisfied all the conditions on its part to be performed or
satisfied at or prior to the Closing Date;

 

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(ii) no stop order suspending the effectiveness of the Registration Statement or
any notice objecting to its use has been issued and no proceedings for that
purpose have been instituted or, to the Issuer’s knowledge, threatened; and

(iii) since the date of the most recent financial statements included in the
Disclosure Package and the Prospectus (exclusive of any amendment or supplement
thereto), there has been no Material Adverse Effect, except as set forth in or
contemplated in the Disclosure Package and the Prospectus (exclusive of any
amendment or supplement thereto).

(f) The Issuer shall have requested and caused PricewaterhouseCoopers LLP to
have furnished to the Representatives, at the Execution Time and at the Closing
Date, letters, dated respectively as of the Execution Time and as of the Closing
Date, in form and substance reasonably satisfactory to the Representatives,
containing statements and information of the type customarily included in
accountant’s “comfort letters” to underwriters, delivered according to Statement
of Auditing Standards No. 72 (or any successor bulletin), with respect to the
audited and unaudited financial statements and certain financial information
contained in the Registration Statement, the Disclosure Package, and each free
writing prospectus, if any.

(g) Subsequent to the Execution Time or, if earlier, the dates as of which
information is given in the Registration Statement (exclusive of any amendment
thereof) and the Prospectus (exclusive of any amendment or supplement thereto),
there shall not have been (i) any change or decrease specified in the letter or
letters referred to in paragraph (e) of this Section 6 or (ii) any change, or
any development involving a prospective change, in or affecting the condition
(financial or otherwise), earnings, business or properties of the Issuer and its
subsidiaries taken as a whole, whether or not arising from transactions in the
ordinary course of business, except as set forth in or contemplated in the
Disclosure Package and the Prospectus (exclusive of any supplement thereto) the
effect of which, in any case referred to in clause (i) or (ii) above, is, in the
sole judgment of the Representatives, so material and adverse as to make it
impractical or inadvisable to proceed with the Offering or delivery of the
Securities as contemplated by the Registration Statement (exclusive of any
amendment thereof), the Disclosure Package and the Prospectus (exclusive of any
amendment or supplement thereto).

(h) Prior to the Closing Date, the Issuer shall have furnished to the
Representatives such further customary information, certificates and documents
as the Representatives may reasonably request.

(i) The Securities shall have been listed and admitted and authorized for
trading on the NASDAQ Global Market, and satisfactory evidence of such actions
shall have been provided to the Representatives.

 

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(j) At the Execution Time, the Issuer shall have furnished to the
Representatives a letter substantially in the form of Exhibit C hereto from each
officer and director of the Issuer and specified stockholders and option holders
of the Issuer, addressed to the Citigroup Global Markets Inc. and Cowen and
Company, LLC.

If any of the conditions specified in this Section 6 shall not have been
fulfilled when and as provided in this Underwriting Agreement, or if any of the
opinions and certificates mentioned above or elsewhere in this Underwriting
Agreement shall not be reasonably satisfactory in form and substance to the
Representatives and counsel for the Underwriters, this Underwriting Agreement
and all obligations of the Underwriters hereunder may be canceled at, or at any
time prior to, the Closing Date by the Representatives.  Notice of such
cancellation shall be given to the Issuer in writing or by telephone or
facsimile confirmed in writing.

The documents required to be delivered by this Section 6 shall be delivered at
the office of Goodwin Procter LLP, counsel for the Underwriters, at 620 Eighth
Avenue, New York, New York 10018, on the Closing Date.

7. Reimbursement of Underwriters’ Expenses.  If the sale of the Securities
provided for herein is not consummated because any condition to the obligations
of the Underwriters set forth in Section 6 hereof is not satisfied, because of
any termination pursuant to Section 10 hereof or because of any refusal,
inability or failure on the part of the Issuer to perform any agreement herein
or comply with any provision hereof other than by reason of a default by any of
the Underwriters, the Issuer will reimburse the Underwriters severally through
Citigroup Global Markets Inc. on demand for all reasonable and documented out of
pocket expenses (including reasonable fees and documented disbursements of
counsel) that shall have been incurred by them in connection with the proposed
purchase and sale of the Securities.

8. Indemnification and Contribution.

(a) The Issuer agrees to indemnify and hold harmless each Underwriter, the
directors, officers, employees, affiliates (within the meaning of Rule 405 under
the Securities Act, each an “Affiliate”) and agents of each Underwriter and each
person who controls any Underwriter within the meaning of either the Securities
Act or the Exchange Act against any and all losses, claims, damages or
liabilities, joint or several, to which they or any of them may become subject
under the Securities Act, the Exchange Act or other Federal or state statutory
law or regulation, at common law or otherwise, insofar as such losses, claims,
damages or liabilities (or actions in respect thereof) arise out of or are based
upon any untrue statement or alleged untrue statement of a material fact
contained in the Registration Statement for the registration of the Securities
as originally filed or in any amendment thereof, or in any Preliminary
Prospectus, or the Prospectus, or any Issuer Free Writing Prospectus, or any
Written Testing-the-Waters Communication or in any amendment thereof or
supplement thereto or arise out of or are based upon the omission or alleged
omission to state therein a material fact required to be stated therein or
necessary to make the statements therein not misleading, and agrees to reimburse
each such indemnified party, as incurred, for any legal or other out of pocket
expenses

 

--------------------------------------------------------------------------------

 

reasonably incurred by them in connection with investigating or defending any
such loss, claim, damage, liability or action; provided, however, that the
Issuer will not be liable in any such case to the extent that any such loss,
claim, damage or liability arises out of or is based upon any such untrue
statement or alleged untrue statement or omission or alleged omission made
therein in reliance upon and in conformity with information furnished in writing
to the Issuer by or on behalf of any Underwriter through the Representatives
specifically for inclusion therein.  This indemnity agreement will be in
addition to any liability which the Issuer may otherwise have.

(b) Each Underwriter severally and not jointly agrees to indemnify and hold
harmless the Issuer, each of its directors, each of its officers who signs the
Registration Statement, and each person who controls the Issuer within the
meaning of either the Securities Act or the Exchange Act, to the same extent as
the foregoing indemnity from the Issuer to each Underwriter, but only with
reference to written information relating to such Underwriter furnished to the
Issuer by or on behalf of such Underwriter through the Representatives
specifically for inclusion in the documents referred to in the foregoing
indemnity.  This indemnity agreement will be in addition to any liability which
any Underwriter may otherwise have.  The Issuer acknowledges that the statements
set forth (i) in the last paragraph of the cover page regarding delivery of the
Securities and, under the heading “Underwriting,” (ii) the list of Underwriters
and their respective participation in the sale of the Securities, (iii) the
paragraph related to concessions and reallowances and (iv) the paragraphs
related to stabilization in the Preliminary Prospectus and the Prospectus
constitute the only information furnished in writing by or on behalf of the
several Underwriters for inclusion in the Preliminary Prospectus, the Prospectus
or any Issuer Free Writing Prospectus.

(c) Promptly after receipt by an indemnified party under this Section 8 of
notice of the commencement of any action, such indemnified party will, if a
claim in respect thereof is to be made against the indemnifying party under this
Section 8, notify the indemnifying party in writing of the commencement thereof;
but the failure so to notify the indemnifying party (i) will not relieve it from
liability under paragraph (a) or (b) above unless and to the extent it did not
otherwise learn of such action and such failure results in the forfeiture by the
indemnifying party of substantial rights and defenses and (ii) will not, in any
event, relieve the indemnifying party from any obligations to any indemnified
party other than the indemnification obligation provided in paragraph (a) or (b)
above.  The indemnifying party shall be entitled to appoint counsel of the
indemnifying party’s choice at the indemnifying party’s expense to represent the
indemnified party in any action for which indemnification is sought (in which
case the indemnifying party shall not thereafter be responsible for the fees and
expenses of any separate counsel retained by the indemnified party or parties
except as set forth below); provided, however, that such counsel shall be
reasonably satisfactory to the indemnified party.  Notwithstanding the
indemnifying party’s election to appoint counsel to represent the indemnified
party in an action, the indemnified party shall have the right to employ
separate counsel (including local counsel), and the indemnifying party shall
bear the reasonable and documented fees, costs and expenses of such separate
counsel (which, if

 

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the Issuer is the indemnifying party, shall be limited to one such separate
counsel for any Underwriter together with all persons who control such
Underwriter within the meaning of either the Act or the Exchange Act) if (i) the
use of counsel chosen by the indemnifying party to represent the indemnified
party would present such counsel with a conflict of interest, (ii) the actual or
potential defendants in, or targets of, any such action include both the
indemnified party and the indemnifying party and the indemnified party shall
have reasonably concluded that there may be legal defenses available to it
and/or other indemnified parties which are different from or additional to those
available to the indemnifying party, (iii) the indemnifying party shall not have
employed counsel reasonably satisfactory to the indemnified party to represent
the indemnified party within a reasonable time after notice of the institution
of such action or (iv) the indemnifying party shall authorize the indemnified
party to employ separate counsel at the expense of the indemnifying party.  An
indemnifying party will not, without the prior written consent of the
indemnified parties, settle or compromise or consent to the entry of any
judgment with respect to any pending or threatened claim, action, suit or
proceeding in respect of which indemnification or contribution may be sought
hereunder (whether or not the indemnified parties are actual or potential
parties to such claim or action) unless such settlement, compromise or consent
(i) includes an unconditional release of each indemnified party from all
liability arising out of such claim, action, suit or proceeding and (ii) does
not include a statement as to or an admission of fault, culpability or a failure
to act, by or on behalf of any indemnified party.

(d) In the event that the indemnity provided in paragraph (a), (b) or (c) of
this Section 8 is unavailable to or insufficient to hold harmless an indemnified
party for any reason, the Issuer and the Underwriters severally agree to
contribute to the aggregate losses, claims, damages and liabilities (including
legal or other expenses reasonably incurred in connection with investigating or
defending the same) (collectively “Losses”) to which the Issuer and one or more
of the Underwriters may be subject in such proportion as is appropriate to
reflect the relative benefits received by the Issuer on the one hand and by the
Underwriters on the other from the Offering.  If the allocation provided by the
immediately preceding sentence is unavailable for any reason, the Issuer and the
Underwriters severally shall contribute in such proportion as is appropriate to
reflect not only such relative benefits but also the relative fault of the
Issuer on the one hand and of the Underwriters on the other in connection with
the statements or omissions which resulted in such Losses as well as any other
relevant equitable considerations.  Benefits received by the Issuer shall be
deemed to be equal to the total net proceeds from the Offering (before deducting
expenses) received by it, and benefits received by the Underwriters shall be
deemed to be equal to the total underwriting discounts and commissions, in each
case as set forth on the cover page of the Prospectus. Relative fault shall be
determined by reference to, among other things, whether any untrue or any
alleged untrue statement of a material fact or the omission or alleged omission
to state a material fact relates to information provided by the Issuer on the
one hand or the Underwriters on the other, the intent of the parties and their
relative knowledge, access to information and opportunity to correct or prevent
such untrue statement or omission.  The Issuer and the Underwriters agree that
it would not be just and equitable if contribution

 

--------------------------------------------------------------------------------

 

were determined by pro rata allocation or any other method of allocation which
does not take account of the equitable considerations referred to
above.  Notwithstanding the provisions of this paragraph (d), (i) in no event
shall an Underwriter be required to contribute any amount in excess of the
amount by which the total underwriting discounts and commissions received by
such Underwriter with respect to the Offering exceeds the amount of any damages
that such Underwriter has otherwise been required to pay by reason of such
untrue or alleged untrue statement or omission or alleged omission and (ii) no
person guilty of fraudulent misrepresentation (within the meaning of
Section 11(f) of the Securities Act) shall be entitled to contribution from any
person who was not guilty of such fraudulent misrepresentation.  For purposes of
this Section 8, each person who controls an Underwriter within the meaning of
either the Securities Act or the Exchange Act and each director, officer,
employee, Affiliate and agent of an Underwriter shall have the same rights to
contribution as such Underwriter, and each person who controls the Issuer within
the meaning of either the Securities Act or the Exchange Act, each officer of
the Issuer who shall have signed the Registration Statement and each director of
the Issuer shall have the same rights to contribution as the Issuer, subject in
each case to the applicable terms and conditions of this paragraph (d).

9. Default by an Underwriter.  If any one or more Underwriters shall fail to
purchase and pay for any of the Securities agreed to be purchased by such
Underwriter or Underwriters hereunder and such failure to purchase shall
constitute a default in the performance of its or their obligations under this
Underwriting Agreement, the remaining Underwriters shall be obligated severally
to take up and pay for (in the respective proportions which the amount of
Securities set forth opposite their names in Schedule I hereto bears to the
aggregate amount of Securities set forth opposite the names of all the remaining
Underwriters) the Securities which the defaulting Underwriter or Underwriters
agreed but failed to purchase; provided, however, that in the event that the
aggregate amount of Securities which the defaulting Underwriter or Underwriters
agreed but failed to purchase shall exceed 10% of the aggregate amount of
Securities set forth in Schedule I hereto, the remaining Underwriters shall have
the right to purchase all, but shall not be under any obligation to purchase
any, of the Securities, and if such non-defaulting Underwriters do not purchase
all the Securities, this Underwriting Agreement will terminate without liability
to any non-defaulting Underwriter or the Issuer.  In the event of a default by
any Underwriter as set forth in this Section 9, the Closing Date shall be
postponed for such period, not exceeding five Business Days, as the
Representatives shall determine in order that the required changes in the
Registration Statement and the Prospectus or in any other documents or
arrangements may be effected.  Nothing contained in this Underwriting Agreement
shall relieve any defaulting Underwriter of its liability, if any, to the Issuer
and any non-defaulting Underwriter for damages occasioned by its default
hereunder.

10. Termination.  This Underwriting Agreement shall be subject to termination in
the absolute discretion of the Representatives, by notice given to the Issuer
prior to delivery of and payment for the Securities, if at any time prior to
such delivery and payment (i) trading in the Issuer’s Common Stock shall have
been suspended by the SEC, the NASDAQ Global Market or trading in securities
generally on the New York Stock Exchange shall have been suspended or limited or
minimum prices shall have been established on either of such exchanges, (ii) a

 

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banking moratorium shall have been declared either by Federal or New York State
authorities, (iii) there shall have occurred a material disruption in commercial
banking or securities settlement or clearance services or (iv) there shall have
occurred any outbreak or escalation of hostilities, declaration by the United
States of a national emergency or war, or other calamity or crisis the effect of
which on financial markets is such as to make it, in the sole judgment of the
Representatives, impractical or inadvisable to proceed with the Offering or
delivery of the Securities as contemplated by the Preliminary Prospectus or the
Prospectus (exclusive of any supplement thereto).  

11. Representations and Indemnities to Survive. The respective agreements,
representations, warranties, indemnities and other statements of the Issuer or
its officers and of the Underwriters set forth in or made pursuant to this
Underwriting Agreement will remain in full force and effect, regardless of any
investigation made by or on behalf of any Underwriter or the Issuer or any of
the officers, directors, employees, agents, Affiliates or controlling persons
referred to in Section 8 hereof, and will survive delivery of and payment for
the Securities.  The provisions of Sections 7 and 8 hereof shall survive the
termination or cancellation of this Underwriting Agreement.

12. Notices. All communications hereunder will be in writing and effective only
on receipt, and, if sent to the Representatives, will be mailed, delivered or
telefaxed to Citigroup Global Markets Inc. General Counsel (fax no.:
1(646) 291-1469) and confirmed to the General Counsel, Citigroup Global Markets
Inc., at 388 Greenwich Street, New York, New York, 10013, Attention: General
Counsel; and to Cowen and Company, LLC (fax no. 1(646) 562-1124) and to be
confirmed to the Head of Equity Capital Markets, Cowen and Company, LLC at 599
Lexington Avenue, New York, New York 10022, Attention: Head of Equity Capital
Markets; or, if sent to Arsanis, Inc., will be mailed, delivered or telefaxed to
890 Winter Street, Suite 230, Waltham, MA 02451, Attention: Chief Executive
Officer.

13. Successors. This Underwriting Agreement will inure to the benefit of and be
binding upon the parties hereto and their respective successors and the
officers, directors, employees, agents and controlling persons referred to in
Section 8 hereof, and no other person will have any right or obligation
hereunder.

14. Jurisdiction.  The Issuer agrees that any suit, action or proceeding against
the Issuer brought by any Underwriter, the directors, officers, employees,
Affiliates and agents of any Underwriter, or by any person who controls any
Underwriter, arising out of or based upon this Underwriting Agreement or the
transactions contemplated hereby may be instituted in any State or U.S. federal
court in The City of New York and County of New York, and waives any objection
which it may now or hereafter have to the laying of venue of any such
proceeding, and irrevocably submits to the non-exclusive jurisdiction of such
courts in any suit, action or proceeding.  The Issuer hereby appoints René
Russo, Pharm.D., BCPS, Arsanis, Inc., 890 Winter Street, Suite 230, Waltham,
Massachusetts 02451, as its authorized agent (the “Authorized Agent”) upon whom
process may be served in any suit, action or proceeding arising out of or based
upon this Underwriting Agreement or the transactions contemplated herein that
may be instituted in any State or U.S. federal court in The City of New York and
County of New York,

 

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by any Underwriter, the directors, officers, employees, Affiliates and agents of
any Underwriter, or by any person who controls any Underwriter, and expressly
accepts the non-exclusive jurisdiction of any such court in respect of any such
suit, action or proceeding.  The Issuer hereby represents and warrants that the
Authorized Agent has accepted such appointment and has agreed to act as said
agent for service of process, and the Issuer agrees to take any and all action,
including the filing of any and all documents that may be necessary to continue
such appointment in full force and effect as aforesaid.  Service of process upon
the Authorized Agent shall be deemed, in every respect, effective service of
process upon the Issuer.  Notwithstanding the foregoing, any action arising out
of or based upon this Underwriting Agreement may be instituted by any
Underwriter, the directors, officers, employees, Affiliates and agents of any
Underwriter, or by any person who controls any Underwriter, in any court of
competent jurisdiction in Massachusetts.

15. No Fiduciary Duty. The Issuer hereby acknowledges that (a) the purchase and
sale of the Securities pursuant to this Underwriting Agreement is an
arm’s-length commercial transaction between the Issuer, on the one hand, and the
Underwriters and any affiliate through which it may be acting, on the other, (b)
the Underwriters are acting as principal and not as an agent or fiduciary of the
Issuer and (c) the Issuer’s engagement of the Underwriters in connection with
the Offering and the process leading up to the Offering is as independent
contractors and not in any other capacity. Furthermore, the Issuer agrees that
it is solely responsible for making its own judgments in connection with the
Offering (irrespective of whether any of the Underwriters has advised or is
currently advising the Issuer on related or other matters).  The Issuer agrees
that it will not claim that the Underwriters have rendered advisory services of
any nature or respect, or owe an agency, fiduciary or similar duty to the
Issuer, in connection with such transaction or the process leading thereto.

16. Integration. This Underwriting Agreement supersedes all prior agreements and
understandings (whether written or oral) between the Issuer and the
Underwriters, or any of them, with respect to the subject matter hereof.

17. Applicable Law.  This Underwriting Agreement will be governed by and
construed in accordance with the laws of the State of New York applicable to
contracts made and to be performed within the State of New York.

18. Waiver of Jury Trial. The Issuer and the Underwriters hereby irrevocably
waive, to the fullest extent permitted by applicable law, any and all right to
trial by jury in any legal proceeding arising out of or relating to this
Underwriting Agreement or the Offering.

19. Counterparts. This Underwriting Agreement may be signed in one or more
counterparts, each of which shall constitute an original and all of which
together shall constitute one and the same agreement.

20. Headings. The section headings used herein are for convenience only and
shall not affect the construction hereof.

 

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If the foregoing is in accordance with your understanding of our agreement,
please sign and return to us the enclosed duplicate hereof, whereupon this
letter and your acceptance shall represent a binding agreement among the Issuer
and the several Underwriters.

 

Very truly yours,

 

 

 

Arsanis, Inc.

 

 

 

By:

 

 

Name:

 

 

Title:

 

 

 

 

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The foregoing Underwriting Agreement is hereby

confirmed and accepted as of the

date first above written.

 

Citigroup Global Markets Inc.

 

 

 

By:

 

 

 

 

Name:

 

 

Title:

 

Cowen and Company, LLC

 

 

 

By:

 

 

 

 

Name:

 

 

Title:

 

Piper Jaffray & Co.

 

 

 

By:

 

 

 

 

Name:

 

 

Title:

 

For themselves and the other

several Underwriters named in

Schedule I to the foregoing

Underwriting Agreement.

 

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SCHEDULE I

 

Underwriters

 

Number of Underwritten Securities

to be Purchased

 

 

 

Citigroup Global Markets Inc.

 

1,600,000

 

 

 

Cowen and Company, LLC                         

 

1,300,000

 

 

 

Piper Jaffray & Co.          

 

1,100,000

 

 

__________

 

 

 

Total

 

4,000,000

 

 

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SCHEDULE II

Schedule of Free Writing Prospectuses included in the Disclosure Package:

None.

 

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SCHEDULE III

Schedule of Written Testing-the-Waters Communications:

 

 

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EXHIBIT A

Form of Wilmer Cutler Pickering Hale and Dorr LLP Opinion

 

 

 

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EXHIBIT B

Form of Redl Life Science Patent Attorneys Opinion

 

 

 

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EXHIBIT C

Form of Lock Up Agreement

Arsanis, Inc.

Public Offering of Common Stock

[•], 2017

Citigroup Global Markets Inc.

Cowen and Company, LLC

As Representatives of the several Underwriters,

c/o Citigroup Global Markets Inc.

388 Greenwich Street

New York, New York 10013

c/o Cowen and Company, LLC

599 Lexington Avenue, 20th Floor

New York, NY 10022

Ladies and Gentlemen:

This letter is being delivered to you in connection with the proposed
underwriting agreement (the “Underwriting Agreement”), between Arsanis, Inc., a
Delaware corporation (the “Issuer”), and each of you as representatives of a
group of underwriters named therein (the “Underwriters”), relating to an
underwritten public offering of common stock, $0.001 par value per share (the
“Common Stock”), of the Issuer (the “Offering”).

In order to induce you and the other Underwriters to enter into the Underwriting
Agreement, the undersigned will not, without the prior written consent of
Citigroup Global Markets Inc. and Cowen and Company, LLC (collectively, the
“Representatives”), offer, sell, contract to sell, pledge or otherwise dispose
of, (or enter into any transaction which is designed to, or might reasonably be
expected to, result in the disposition (whether by actual disposition or
effective economic disposition due to cash settlement or otherwise) by the
undersigned or any affiliate of the undersigned or any person in privity with
the undersigned or any affiliate of the undersigned), directly or indirectly,
including the filing, whether publicly or confidentially, (or participation in
the filing) of a registration statement (other than a registration statement on
Form S-8) with the Securities and Exchange Commission (the “SEC”) in respect of,
or establish or increase a put equivalent position or liquidate or decrease a
call equivalent position within the meaning of Section 16 of the Securities
Exchange Act of 1934, as amended (the “Exchange Act”), and the rules and
regulations of the SEC promulgated thereunder with respect to, any shares of
capital stock of the Issuer or any securities convertible into, or exercisable
or exchangeable for such capital stock, or publicly announce an intention to
effect any such transaction, for a period from the date hereof through 180 days
after the date of the Underwriting Agreement (the “Lock-Up Period”).  If the
undersigned is an officer or director of the Issuer, the

 

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undersigned further agrees that the foregoing restrictions shall be equally
applicable to any issuer-directed shares of Common Stock the undersigned may
purchase in the Offering.

The provisions of the immediately preceding paragraph shall not apply to or
prohibit any of the following:

 

(i)

the sale of shares of Common Stock by the undersigned to the Underwriters
pursuant to the Underwriting Agreement;

 

(ii)

transactions relating to shares of Common Stock or other securities acquired in
the Offering or in open market transactions after the completion of the
Offering;

 

(iii)

transfers of shares of capital stock of the Issuer or any securities convertible
into, or exercisable or exchangeable for such capital stock as a bona fide gift
or gifts;

 

(iv)

transfers or dispositions of shares of capital stock of the Issuer or any
securities convertible into, or exercisable or exchangeable for such capital
stock to any trust for the direct or indirect benefit of the undersigned or the
immediate family of the undersigned in a transaction not involving a disposition
for value;

 

(v)

transfers or dispositions of shares of capital stock of the Issuer or any
securities convertible into, or exercisable or exchangeable for such capital
stock to any corporation, partnership, limited liability company or other entity
all of the beneficial ownership interests of which are held by the undersigned
or the immediate family of the undersigned in a transaction not involving a
disposition for value;

 

(vi)

transfers or dispositions of shares of capital stock of the Issuer or any
securities convertible into, or exercisable or exchangeable for such capital
stock by will, other testamentary document or intestate succession to the legal
representative, heir, beneficiary or a member of the immediate family of the
undersigned; or

 

(vii)

distributions of shares of capital stock of the Issuer or any securities
convertible into, or exercisable or exchangeable for such capital stock to
partners, members or stockholders of the undersigned;

provided, that, in the case of clauses (i) and (ii) (a) no filing under
Section 13 or Section 16(a) of the Exchange Act reporting a reduction in
beneficial ownership of shares of Common Stock shall be required during the
Lock-Up Period, other than Forms 5 and Schedule 13F, and (b) no filing under
Section 13 or Section 16(a) of the Exchange Act or other public announcement
shall be voluntarily made by the undersigned during the Lock-Up Period, other
than Forms 5 and Schedule 13F; provided further that in the case of any transfer
or distribution pursuant to clauses (iii), (iv), (v), (vi) and (vii) (a) the
recipient agrees to be bound in writing by the same restrictions set forth
herein for the duration of the Lock-Up Period, (b) no filing under Section 13 or
Section

 

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16(a) of the Exchange Act reporting a reduction in beneficial ownership of
shares of Common Stock shall be required during the Lock-Up Period, other than
Forms 5 and Schedule 13F and (c) no filing under Section 13 of Section 16(a) of
the Exchange Act or other public announcement shall be voluntarily made by the
undersigned or the transferee during the Lock-Up Period, other than Forms 5 and
Schedule 13F and (d) any such transfer shall not involve a disposition for
value.

Notwithstanding the restrictions imposed by this letter, the undersigned may,
without the prior written consent of the Representatives, (a) exercise, in cash
or by means of a net exercise, an option to purchase shares of Common Stock
granted under any stock incentive plan or stock purchase plan of the Issuer or
exercise outstanding warrants to purchase shares of the Issuer’s capital stock,
provided that the underlying shares issuable upon exercise thereof shall
continue to be subject to the restrictions on transfer set forth in this letter,
(b) establish a trading plan pursuant to Rule 10b5-1 under the Exchange Act for
the transfer of shares of Common Stock, provided that such plan does not provide
for any transfers of Common Stock, and no filing with the SEC or other public
announcement shall be required or voluntarily made by the undersigned or any
other person in connection therewith, in each case during the 180-day period
referred to in the immediately preceding paragraph and (c) transfer shares of
Common Stock to the Issuer in connection with the termination of the
undersigned’s employment with the Issuer.

If the undersigned is an officer or director of the Issuer, (i) the
Representatives agree that, at least three business days before the effective
date of any release or waiver of the foregoing restrictions in connection with a
transfer of shares of Common Stock, the Representatives will notify the Issuer
of the impending release or waiver and (ii) the Issuer has agreed in the
Underwriting Agreement to announce the impending release or waiver by press
release through a major news service at least two business days before the
effective date of the release or waiver.  Any release or waiver granted by the
Representatives hereunder to any such officer or director shall only be
effective two business days after the publication date of such press
release.  The provisions of this paragraph will not apply if (a) the release or
waiver is effected solely to permit a transfer not for consideration and (b) the
transferee has agreed in writing to be bound by the same terms described in this
letter to the extent and for the duration that such terms remain in effect at
the time of the transfer.

This letter shall automatically terminate and the undersigned shall be released
from all obligations under this letter upon the earliest to occur, if any, of
(i) either the Issuer, on the one hand, or the Representatives, on the other
hand, advising the other in writing, prior to the execution of the Underwriting
Agreement, that they have determined not to proceed with the Offering, (ii) the
Underwriting Agreement being terminated prior to the Closing Date (as defined in
the Underwriting Agreement), (iii) the registration statement filed with the SEC
with respect to the Offering being withdrawn and (iv) February 16, 2018, in the
event that the Underwriting Agreement has not been executed by such date.

 

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Yours very truly,

 

Exact Name of Stockholder

 

Authorized Signature

 

Title (if signing on behalf of an entity)

 

 

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ADDENDUM

Form of Waiver of Lock-up

 

ARSANIS, INC.

Public Offering of Common Stock

[insert date], 20__

[insert name receiving waiver]

[insert address]

Dear Mr./Ms. [insert name]:

This letter is being delivered to you in connection with the offering by
Arsanis, Inc. (the “Issuer”) of [•] shares of common stock, $0.001 par value per
share (the “Common Stock”), of the Issuer and the lock-up letter dated [●], 2017
(the “Lock-up Letter”), executed by you in connection with such offering, and
your request for a [waiver] [release] dated [insert date], 20[•], with respect
to [•] shares of Common Stock (the “Shares”).

Citigroup Global Markets Inc. and Cowen and Company, LLC hereby agree to [waive]
[release] the transfer restrictions set forth in the Lock-up Letter, but only
with respect to the Shares, effective [insert date], 20[•]; provided, however,
that such [waiver] [release] is conditioned on the Issuer announcing the
impending [waiver] [release] by press release through a major news service at
least two business days before effectiveness of such [waiver] [release].  This
letter will serve as notice to the Issuer of the impending [waiver] [release].  

Except as expressly [waived] [released] hereby, the Lock-up Letter shall remain
in full force and effect.

 

Yours very truly,

 

Citigroup Global Markets Inc.

 

 

 

By:

 

 

 

 

Name:

 

 

Title:

 

Cowen and Company, LLC

 

 

 

By:

 

 

 

 

Name:

 

 

Title:

 

 

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EXHIBIT B

Form of WilmerHale Opinion