EX-4.5



 Exhibit 4.5 

ACASTI PHARMA INC. 
 and 

COMPUTERSHARE INC. AND ITS WHOLLY-OWNED SUBSIDIARY, 

COMPUTERSHARE TRUST COMPANY N.A., as 

Warrant Agent 
 Warrant Agency
Agreement 
 Dated as of December     , 2017 







 WARRANT AGENCY AGREEMENT 

WARRANT AGENCY AGREEMENT, dated as of
                    , 2017 (“Agreement”), between Acasti Pharma Inc., a Canadian corporation organized under the laws of
Québec (the “Company”), Computershare Inc., a Delaware corporation (“Computershare”), and its wholly-owned subsidiary Computershare Trust Company N.A. a federally chartered trust company, (collectively, the
“Warrant Agent”). 
 W I T N E S S E T H 

WHEREAS, pursuant to a registered offering by the Company of common shares, no par value (the “Common Shares”), and warrants
to purchase Common Shares (the “Warrants”), pursuant to an effective registration statement on Form F-1 (File No. 333-220755) (the
“Registration Statement”), the Company wishes to issue Warrants in book entry form entitling the respective holders of the Warrants (the “Holders”, which term shall include a Holder’s transferees, successors
and assigns and “Holder” shall include, if the Warrants are held in “street name”, a Participant (as defined below) or a designee appointed by such Participant) to purchase an aggregate of up to [●]Common Shares
(which includes Warrants to purchase up to [●]Common Shares pursuant to an overallotment option granted to the underwriters) upon the terms and subject to the conditions hereinafter set forth (the “Offering”); 

WHEREAS, the Common Shares and Warrants to be issued in connection with the Offering shall be immediately separable and will be issued
separately, but will be purchased together in the Offering; and 
 WHEREAS, the Company wishes the Warrant Agent to act on behalf of the
Company, and the Warrant Agent is willing so to act, in connection with the issuance, registration, transfer, exchange, exercise and replacement of the Warrants and, in the Warrant Agent’s capacity as the Company’s transfer agent, the
delivery of the Warrant Shares (as defined below). 
 NOW, THEREFORE, in consideration of the premises and the mutual agreements herein set
forth, the parties hereby agree as follows: 
 Section 1.    Certain Definitions. For purposes of this
Agreement, the following terms have the meanings indicated: 
 (a)    “Affiliate” has the meaning
ascribed to it in Rule 12b-2 under the Securities Exchange Act of 1934, as amended (the “Exchange Act”). 

(b)    “Business Day” means any day except any Saturday, any Sunday, any day which is a federal legal
holiday in Canada or the United States or any day on which the TSX Venture Exchange or the Nasdaq Stock Market is authorized or required by law or other governmental action to close. 

(c)    “Close of Business” on any given date means 5:00 p.m., New York City time, on such date;
provided, however, that if such date is not a Business Day it means 5:00 p.m., New York City time, on the next succeeding Business Day. 

  
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 (d)    “Person” means an individual, corporation,
association, partnership, limited liability company, joint venture, trust, unincorporated organization, government or political subdivision thereof or governmental agency or other entity. 

(e)    “Warrant Certificate” means a certificate in substantially the form attached as Exhibit 1
hereto, representing such number of Warrant Shares as is indicated therein, provided that any reference to the delivery of a Warrant Certificate in this Agreement shall include delivery of notice from the Depositary or a Participant (each as defined
below) of the transfer or exercise of Warrant in the form of a Global Warrant (as defined below). 

(f)    “Warrant Shares” means the Common Shares underlying the Warrants and issuable upon exercise of the
Warrants. 
 All other capitalized terms used but not otherwise defined herein shall have the meaning ascribed to such terms in the Warrant
Certificate. 
 Section 2.    Appointment of Warrant Agent. The Company hereby appoints the Warrant Agent to
act as agent for the Company in accordance with the terms and conditions hereof, and the Warrant Agent hereby accepts such appointment. 

Section 3.    Global Warrants. 

(a)    Unless otherwise issued in physical certificated form, the Warrants shall be issuable in book entry form (the
“Global Warrants”) and shall initially be represented by one or more Global Warrants, in the form of the Warrant Certificate, deposited with the Warrant Agent and registered in the name of Cede & Co., a nominee of The
Depository Trust Company (the “Depositary”), or as otherwise directed by the Depositary. Ownership of beneficial interests in the Warrants shall be shown on, and the transfer of such ownership shall be effected through, records
maintained by (i) the Depositary or its nominee for each Global Warrant or (ii) institutions that have accounts with the Depositary (such institution, with respect to a Warrant in its account, a “Participant”). 

(b)    If the Depositary subsequently ceases to make its book-entry settlement system available for the Warrants, the
Company may instruct the Warrant Agent regarding other arrangements for book-entry settlement. In the event that the Warrants are not eligible for, or it is no longer necessary to have the Warrants available in, book-entry form, the Warrant Agent
shall provide written instructions to the Depositary to deliver to the Warrant Agent for cancellation each Global Warrant, and the Company shall instruct the Warrant Agent to deliver to each Holder a Warrant Certificate. 

  
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 (c)    A Holder has the right to elect at any time or from time to time a
Warrant Exchange (as defined below) pursuant to a Warrant Certificate Request Notice (as defined below). Upon written notice by a Holder to the Warrant Agent for the exchange of some or all of such Holder’s Global Warrants for a Warrant
Certificate evidencing the same number of Warrants, which request shall be in the form attached hereto as Annex A (a “Warrant Certificate Request Notice” and the date of delivery of such Warrant Certificate Request Notice by
the Holder, the “Warrant Certificate Request Notice Date” and the deemed surrender upon delivery by the Holder of a number of Global Warrants for the same number of Warrants evidenced by a Warrant Certificate, a “Warrant
Exchange”), the Warrant Agent shall promptly effect the Warrant Exchange and shall promptly issue and deliver to the Holder a Warrant Certificate for such number of Warrants in the name set forth in the Warrant Certificate Request Notice.
Such Warrant Certificate shall be dated the original issue date of the Warrants, shall be manually executed by an authorized signatory of the Company, shall be in the form attached hereto as Exhibit 1, and shall be reasonably acceptable in
all respects to such Holder. In connection with a Warrant Exchange, the Company agrees to deliver, or to direct the Warrant Agent to deliver, the Warrant Certificate to the Holder within three (3) Business Days of the Warrant Certificate
Request Notice pursuant to the delivery instructions in the Warrant Certificate Request Notice (“Warrant Certificate Delivery Date”). If the Company fails for any reason to deliver to the Holder the Warrant Certificate subject to
the Warrant Certificate Request Notice by the Warrant Certificate Delivery Date, the Company shall pay to the Holder, in cash, as liquidated damages and not as a penalty, for each $1,000 of Warrant Shares evidenced by such Warrant Certificate (based
on the VWAP (as defined in the Warrants) of the Common Shares on the Warrant Certificate Request Notice Date), $10 per Business Day for each Business Day after such Warrant Certificate Delivery Date until such Warrant Certificate is delivered or,
prior to delivery of such Warrant Certificate, the Holder rescinds such Warrant Exchange. The Company covenants and agrees that, upon the date of delivery of the Warrant Certificate Request Notice, the Holder shall be deemed to be the holder of the
Warrant Certificate and, notwithstanding anything to the contrary set forth herein, the Warrant Certificate shall be deemed for all purposes to contain all of the terms and conditions of the Warrants evidenced by such Warrant Certificate and the
terms of this Agreement, other than Sections 3(c) and 9 herein, shall not apply to the Warrants evidenced by the Warrant Certificate. Notwithstanding anything herein to the contrary, the Company shall act as warrant agent with respect to any
physical Warrant Certificate requested and issued pursuant to this section. 
 (d)    Notwithstanding anything to the
contrary included in this Section 3 or anywhere else in this Agreement, Warrants that are issued to, or for the benefit of, a Person resident in any province or territory of Canada shall be issued in the form of the Warrant Certificate and, in
addition to the terms and provisions set forth thereon, such Warrant Certificate shall also bear the following legend: 
 “UNLESS
PERMITTED UNDER SECURITIES LEGISLATION, THE HOLDER OF THIS SECURITY MUST NOT TRADE THE SECURITY IN CANADA OR TO OR FOR THE BENEFIT OF A CANADIAN RESIDENT BEFORE [INSERT DATE THAT IS 4 MONTHS AND A DAY FOLLOWING CLOSING]” 

Each certificate for the Warrant Shares purchased under the Warrant issued upon exercise of the Warrant by, or for the benefit of, a Person
resident in any province or territory of Canada prior to the date that is four months and a day following the issuance date of the Warrants, or if the Warrant Shares purchased under the Warrants are entered into a direct registration or other
electronic book-entry only system, such Warrant Shares shall also bear the legend set forth above. 

  
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 Section 4.    Form of Warrant Certificates. The Warrant
Certificate, together with the form of election to purchase Common Shares (“Notice of Exercise”) and the form of assignment to be printed on the reverse thereof, shall be in the form of Exhibit 1 hereto. 

Section 5.    Countersignature and Registration. The Warrant Certificates shall be executed on behalf of the
Company by its Chief Executive Officer, Chief Financial Officer or Vice President, either manually or by facsimile signature. The Warrant Certificates shall be countersigned by the Warrant Agent by facsimile signature and shall not be valid for any
purpose unless so countersigned. In case any officer of the Company who shall have signed any of the Warrant Certificates shall cease to be such officer of the Company before countersignature by the Warrant Agent and issuance and delivery by the
Company, such Warrant Certificates, nevertheless, may be countersigned by the Warrant Agent, issued and delivered with the same force and effect as though the person who signed such Warrant Certificate had not ceased to be such officer of the
Company; and any Warrant Certificate may be signed on behalf of the Company by any person who, at the actual date of the execution of such Warrant Certificate, shall be a proper officer of the Company to sign such Warrant Certificate, although at
the date of the execution of this Warrant Agreement any such person was not such an officer. 
 The Warrant Agent will keep or cause to be
kept, at one of its offices, or at the office of one of its agents, books for registration and transfer of the Warrant Certificates issued hereunder. Such books shall show the names and addresses of the respective Holders of the Warrant
Certificates, the number of warrants evidenced on the face of each of such Warrant Certificate and the date of each of such Warrant Certificate. The Warrant Agent will create a special account for the issuance of Warrant Certificates. 

Section 6.    Transfer, Split Up, Combination and Exchange of Warrant Certificates; Mutilated, Destroyed, Lost or
Stolen Warrant Certificates. With respect to the Global Warrant, subject to the provisions of the Warrant Certificate and the last sentence of this first paragraph of Section 6 and subject to applicable law, rules or regulations, or any
“stop transfer” instructions the Company may give to the Warrant Agent, at any time after the closing date of the Offering, and at or prior to the Close of Business on the Termination Date (as such term is defined in the Warrant
Certificate), any Warrant Certificate or Warrant Certificates or Global Warrant or Global Warrants may be transferred, split up, combined or exchanged for another Warrant Certificate or Warrant Certificates or Global Warrant or Global Warrants,
entitling the Holder to purchase a like number of Common Shares as the Warrant Certificate or Warrant Certificates or Global Warrant or Global Warrants surrendered then entitled such Holder to purchase. Any Holder desiring to transfer, split up,
combine or exchange any Warrant Certificate or Global Warrant shall make such request in writing delivered to the Warrant Agent, and shall surrender the Warrant Certificate or Warrant Certificates to be transferred, split up, combined or exchanged
at the principal office of the Warrant Agent, provided that no such surrender is applicable to the Holder of a Global Warrant. Any requested transfer of Warrants, whether in book-entry form or certificate form, shall be accompanied by reasonable
evidence of authority of the party making such request that may be required by the Warrant Agent. Thereupon the Warrant Agent shall, subject to the last sentence of this first paragraph of Section 6, countersign and deliver to the Person
entitled thereto a Warrant Certificate or Warrant Certificates, as the case may be, as so requested. The Company may require payment from the Holder of a sum sufficient to cover any tax or governmental charge that may be imposed in connection with
any transfer, split up, combination or exchange of Warrant Certificates. The Company shall compensate the Warrant Agent per the fee schedule mutually agreed upon by the parties hereto and provided separately on the date hereof. A party requesting
transfer of a Warrant Certificate must provide any evidence of authority that may be required by the Warrant Agent, including but not limited to, a signature guarantee from an eligible guarantor institution participating in a signature guarantee
program approved by the Securities Transfer Association. 

  
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 Upon receipt by the Warrant Agent of evidence reasonably satisfactory to it of the loss, theft,
destruction or mutilation of a Warrant Certificate, which evidence shall include an affidavit of loss, or in the case of mutilated certificates, the certificate or portion thereof remaining, and, in case of loss, theft or destruction, of indemnity
in customary form and amount, provision of a bond, and satisfaction of any other reasonable requirements established by Section 8-405 of the Uniform Commercial Code as in effect in the State of Delaware,
and reimbursement to the Company and the Warrant Agent of all reasonable expenses incidental thereto, and upon surrender to the Warrant Agent and cancellation of the Warrant Certificate if mutilated, the Company will make and deliver a new Warrant
Certificate of like tenor to the Warrant Agent for delivery to the Holder in lieu of the Warrant Certificate so lost, stolen, destroyed or mutilated. 

Section 7.     Exercise of Warrants; Exercise Price; Termination Date. 

(a)     The Warrants shall be exercisable commencing on the Initial Exercise Date. The Warrants shall cease to be
exercisable and shall terminate and become void, and all rights thereunder and under this Agreement shall cease, at or prior to the Close of Business on the Termination Date. Subject to the foregoing and to Section 7(b) below, the Holder of a
Warrant may exercise the Warrant in whole or in part upon surrender of the Warrant Certificate, if required, with the executed Notice of Exercise and payment of the Exercise Price, which may be made, at the option of the Holder, by wire transfer or
by certified or official bank check in United States dollars, to the Warrant Agent at the principal office of the Warrant Agent or to the office of one of its agents as may be designated by the Warrant Agent from time to time. In the case of the
Holder of a Global Warrant, the Holder shall deliver the executed Notice of Exercise and the payment of the Exercise Price as described herein. Notwithstanding any other provision in this Agreement, a holder whose interest in a Global Warrant is a
beneficial interest in a Global Warrant held in book-entry form through the Depositary (or another established clearing corporation performing similar functions), shall effect exercises by delivering to the Depositary (or such other clearing
corporation, as applicable) the appropriate instruction form for exercise, complying with the procedures to effect exercise that are required by the Depositary (or such other clearing corporation, as applicable). The Company acknowledges that the
bank accounts maintained by the Warrant Agent in connection with the services provided under this Agreement will be in its name and that the Warrant Agent may receive investment earnings in connection with the investment at Warrant Agent risk and
for its benefit of funds held in those accounts from time to time. Neither the Company nor the Holders will receive interest on any deposits or Exercise Price. No ink-original Notice of Exercise shall be
required, nor shall any medallion guarantee (or other type of guarantee or notarization) of any Notice of Exercise be required. 
 (b)
    Upon receipt of a Notice of Exercise for a Cashless Exercise, the Company will promptly calculate and transmit to the Warrant Agent the number of Warrant Shares issuable in connection with such Cashless Exercise and deliver a
copy of the Notice of Exercise to the Warrant Agent, which shall issue such number of Warrant Shares in connection with such Cashless Exercise. 

  
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 (c)     Upon the Warrant Agent’s receipt of a Warrant Certificate at or
prior to the Close of Business on the Termination Date set forth in such Warrant Certificate, with the executed Notice of Exercise, accompanied by payment of the Exercise Price for the shares to be purchased (other than in the case of a Cashless
Exercise) and an amount equal to any applicable tax, governmental charge or expense reimbursement referred to in Section 6 by wire transfer, or by certified check or bank draft payable to the order of the Company (or, in the case of the Holder
of a Global Warrant, the delivery of the executed Notice of Exercise and the payment of the Exercise Price (other than in the case of a Cashless Exercise) and any other applicable amounts as set forth herein), the Warrant Agent shall cause the
Warrant Shares underlying such Warrant Certificate or Global Warrant to be delivered to or upon the order of the Holder of such Warrant Certificate or Global Warrant, registered in such name or names as may be designated by such Holder, no later
than the Warrant Share Delivery Date (as such term is defined in the Warrant Certificate). If the Company is then a participant in the DWAC system of the Depositary and either (A) there is an effective registration statement permitting the
issuance of the Warrant Shares to or resale of the Warrant Shares by Holder or (B) the Warrant is being exercised via Cashless Exercise, then, unless subject to the requirements of Section 3(d) above, the certificates for Warrant Shares
shall be transmitted by the Warrant Agent to the Holder by crediting the account of the Holder’s broker with the Depositary through its DWAC system. For the avoidance of doubt, if the Company becomes obligated to pay any amounts to any Holders
pursuant to Section 2(d)(i) or 2(d)(iv) of the Warrant Certificate, such obligation shall be solely that of the Company and not that of the Warrant Agent. Notwithstanding anything else to the contrary in this Agreement, except in the case of a
Cashless Exercise, if any Holder fails to duly deliver payment to the Warrant Agent of an amount equal to the aggregate Exercise Price of the Warrant Shares to be purchased upon exercise of such Holder’s Warrant as set forth in
Section 7(a) hereof by the Warrant Share Delivery Date, the Warrant Agent will not obligated to deliver such Warrant Shares (via DWAC or otherwise) until following receipt of such payment, and the applicable Warrant Share Delivery Date shall be
deemed extended by one day for each day (or part thereof) until such payment is delivered to the Warrant Agent.  

(d)     The Warrant Agent shall deposit all funds received by it in payment of the Exercise Price for all Warrants in the
account of the Company maintained with the Warrant Agent for such purpose (or to such other account as directed by the Company in writing) and shall advise the Company via email at the end of each day on which notices of exercise are received or
funds for the exercise of any Warrant are received of the amount so deposited to its account. 
 (e)     In case the
Holder of any Warrant Certificate shall exercise fewer than all Warrants evidenced thereby, a new Warrant Certificate evidencing the number of Warrants equivalent to the number of Warrants remaining unexercised may be issued by the Warrant Agent to
the Holder of such Warrant Certificate or to his duly authorized assigns in accordance with Section 2(d)(ii) of the Warrant Certificate, subject to the provisions of Section 6 hereof. 

  
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 Section 8.     Cancellation and Destruction of Warrant
Certificates. All Warrant Certificates surrendered for the purpose of exercise, transfer, split up, combination or exchange shall, if surrendered to the Company or to any of its agents, be delivered to the Warrant Agent for cancellation or in
canceled form, or, if surrendered to the Warrant Agent, shall be canceled by it, and no Warrant Certificates shall be issued in lieu thereof except as expressly permitted by any of the provisions of this Agreement. The Company shall deliver to the
Warrant Agent for cancellation and retirement, and the Warrant Agent shall so cancel and retire, any other Warrant Certificate purchased or acquired by the Company otherwise than upon the exercise thereof. The Warrant Agent shall deliver all
canceled Warrant Certificates to the Company, or shall, at the written request of the Company, destroy such canceled Warrant Certificates, and in such case shall deliver a certificate of destruction thereof to the Company, subject to any applicable
law, rule or regulation requiring the Warrant Agent to retain such canceled certificates. 
 Section 9.
    Certain Representations; Reservation and Availability of Common Shares or Cash. 
 (a)
    This Agreement has been duly authorized, executed and delivered by the Company and, assuming due authorization, execution and delivery hereof by the Warrant Agent, constitutes a valid and legally binding obligation of the
Company enforceable against the Company in accordance with its terms, and the Warrants have been duly authorized, executed and issued by the Company and, assuming due authentication thereof by the Warrant Agent pursuant hereto and payment therefor
by the Holders as provided in the Registration Statement, constitute valid and legally binding obligations of the Company enforceable against the Company in accordance with their terms and entitled to the benefits hereof; in each case except as
enforceability may be limited by bankruptcy, insolvency, reorganization, moratorium and other similar laws relating to or affecting creditors’ rights generally or by general equitable principles (regardless of whether such enforceability is
considered in a proceeding in equity or at law). 
 (b)     As of the date hereof, the authorized capital shares of the
Company consists of an unlimited number of Common Shares, of which [●] Common Shares are issued and outstanding, and [●] Common Shares are reserved for issuance upon exercise of the Warrants. Except as disclosed in the Registration
Statement, there are no other outstanding obligations, warrants, options or other rights to subscribe for or purchase from the Company any class of capital shares of the Company. 

(c)     The Company covenants and agrees that it will cause to be reserved and kept available out of its authorized and
unissued Common Shares or its authorized and issued Common Shares held in its treasury, free from preemptive rights, the number of Common Shares that will be sufficient to permit the exercise in full of all outstanding Warrants. 

(d)     The Warrant Agent will create a special account for the issuance of Common Shares upon the exercise of Warrants.


  
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 (e)     The Company further covenants and agrees that it will pay when due
and payable any and all federal and state transfer taxes and charges which may be payable in respect of the original issuance or delivery of the Warrant Certificates or certificates evidencing Common Shares upon exercise of the Warrants. The Company
shall not, however, be required to pay any tax or governmental charge which may be payable in respect of any transfer involved in the transfer or delivery of Warrant Certificates or the issuance or delivery of certificates for Common Shares in a
name other than that of the Holder of the Warrant Certificate evidencing Warrants surrendered for exercise or to issue or deliver any certificate for Common Shares upon the exercise of any Warrants until any such tax or governmental charge shall
have been paid (any such tax or governmental charge being payable by the Holder of such Warrant Certificate at the time of surrender) or until it has been established to the Company’s reasonable satisfaction that no such tax or governmental
charge is due. 
 Section 10.     Common Share Record Date. Each Person in whose name any certificate for
Common Shares is issued (or to whose broker’s account is credited Common Shares through the DWAC system) upon the exercise of Warrants shall for all purposes be deemed to have become the holder of record for the Common Shares represented
thereby on, and such certificate shall be dated, the date on which submission of the Notice of Exercise was made, provided that the Warrant Certificate evidencing such Warrant is duly surrendered (but only if required herein) and payment of the
Exercise Price (and any applicable transfer taxes) is received on or prior to the Warrant Share Delivery Date; provided, however, that if the date of submission of the Notice of Exercise is a date upon which the Common Share transfer
books of the Company are closed, such Person shall be deemed to have become the record holder of such shares on, and such certificate shall be dated, the next succeeding day on which the Common Share transfer books of the Company are open. 

Section 11.     Adjustment of Exercise Price, Number of Common Shares or Number of the Company Warrants. The
Exercise Price, the number of shares covered by each Warrant and the number of Warrants outstanding are subject to adjustment from time to time as provided in Section 3 of the Warrant Certificate. In the event that at any time, as a result of
an adjustment made pursuant to Section 3 of the Warrant Certificate, the Holder of any Warrant thereafter exercised shall become entitled to receive any shares in the capital of the Company other than Common Shares, thereafter the number of
such other shares so receivable upon exercise of any Warrant shall be subject to adjustment from time to time in a manner and on terms as nearly equivalent as practicable to the provisions with respect to the shares contained in Section 3 of
the Warrant Certificate, and the provisions of Sections 7, 9 and 13 of this Agreement with respect to the Common Shares shall apply on like terms to any such other shares. All Warrants originally issued by the Company subsequent to any adjustment
made to the Exercise Price pursuant to the Warrant Certificate shall evidence the right to purchase, at the adjusted Exercise Price, the number of Common Shares purchasable from time to time hereunder upon exercise of the Warrants, all subject to
further adjustment as provided herein. 
 Section 12.     Certification of Adjusted Exercise Price or Number of
Common Shares. Whenever the Exercise Price or the number of Common Shares issuable upon the exercise of each Warrant is adjusted as provided in Section 11 or 13, the Company shall (a) promptly prepare a certificate setting forth the
Exercise Price of each Warrant as so adjusted, and a brief statement of the facts accounting for such adjustment, (b) promptly file with the Warrant Agent and with each transfer agent for the Common Shares a copy of such certificate and
(c) instruct the Warrant Agent to send a brief summary thereof to each Holder of a Warrant Certificate. The Company further agrees that it will provide the Warrant Agent with any new or amended exercise terms. 

  
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 Section 13.     Fractional Common Shares. 

(a)     The Company shall not issue fractions of Warrants or distribute Warrant Certificates which evidence fractional
Warrants. Whenever any fractional Warrant would otherwise be required to be issued or distributed, the actual issuance or distribution shall reflect a rounding of such fraction to the nearest whole Warrant (rounded down). 

(b)     The Company shall not issue fractions of Common Shares upon exercise of Warrants or distribute share certificates
which evidence fractional Common Shares. Whenever any fraction of a Common Share would otherwise be required to be issued or distributed, the actual issuance or distribution in respect thereof shall be made in accordance with Section 2(d)(v) of
the Warrant Certificate. 
 Section 14.     Conditions of the Warrant Agent’s Obligations. The Warrant
Agent accepts its obligations herein set forth upon the terms and conditions hereof, including the following to all of which the Company agrees and to all of which the rights hereunder of the Holders from time to time of the Warrant Certificates
shall be subject: 
 (a)    Compensation and Indemnification. The Company agrees promptly to pay the Warrant
Agent the compensation detailed on Exhibit 2 hereto for all services rendered by the Warrant Agent and to reimburse the Warrant Agent for reasonable out-of-pocket
expenses (including reasonable counsel fees) incurred without gross negligence or willful misconduct finally adjudicated to have been directly caused by the Warrant Agent in connection with the services rendered hereunder by the Warrant Agent. The
Company also agrees to indemnify the Warrant Agent for, and to hold it harmless against, any loss, liability or expense incurred without gross negligence, bad faith or willful misconduct on the part of the Warrant Agent, finally adjudicated to have
been directly caused by Warrant Agent hereunder, including the reasonable costs and expenses of defending against any claim of such liability. The Warrant Agent shall be under no obligation to institute or defend any action, suit, or legal
proceeding in connection herewith or to take any other action likely to involve the Warrant Agent in expense, unless first indemnified to the Warrant Agent’s satisfaction. The indemnities provided by this paragraph shall survive the resignation
or discharge of the Warrant Agent or the termination of this Agreement. Anything in this Agreement to the contrary notwithstanding, in no event shall the Warrant Agent be liable under or in connection with the Agreement for indirect, special,
incidental, punitive or consequential losses or damages of any kind whatsoever, including but not limited to lost profits, whether or not foreseeable, even if the Warrant Agent has been advised of the possibility thereof and regardless of the form
of action in which such damages are sought, and the Warrant Agent’s aggregate liability to the Company, or any of the Company’s representatives or agents, under this Section 14(a) or under any other term or provision of this
Agreement, whether in contract, tort, or otherwise, is expressly limited to, and shall not exceed in any circumstances, one years fees received by the Warrant Agent as fees and charges under this Agreement, but not including reimbursable expenses
previously reimbursed to the Warrant Agent by the Company hereunder. 

  
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 (b)    Agent for the Company. In acting under this Warrant Agreement
and in connection with the Warrant Certificates, the Warrant Agent is acting solely as agent of the Company and does not assume any obligations or relationship of agency or trust for or with any of the Holders of Warrant Certificates or beneficial
owners of Warrants. 
 (c)    Counsel. The Warrant Agent may consult with counsel satisfactory to it, which may
include counsel for the Company, and the written advice of such counsel shall be full and complete authorization and protection in respect of any action taken, suffered or omitted by it hereunder in good faith and in accordance with the advice of
such counsel. 
 (d)    Documents. The Warrant Agent shall be protected and shall incur no liability for or in
respect of any action taken or omitted by it in reliance upon any Warrant Certificate, notice, direction, consent, certificate, affidavit, statement or other paper or document reasonably believed by it to be genuine and to have been presented or
signed by the proper parties. 
 (e)    Certain Transactions. The Warrant Agent, and its officers, directors and
employees, may become the owner of, or acquire any interest in, Warrants, with the same rights that it or they would have if it were not the Warrant Agent hereunder, and, to the extent permitted by applicable law, it or they may engage or be
interested in any financial or other transaction with the Company and may act on, or as depositary, trustee or agent for, any committee or body of Holders of Warrants or other obligations of the Company as freely as if it were not the Warrant Agent
hereunder. Nothing in this Warrant Agreement shall be deemed to prevent the Warrant Agent from acting as trustee under any indenture to which the Company is a party. 

(f)    No Liability for Interest. Unless otherwise agreed with the Company, the Warrant Agent shall have no
liability for interest on any monies at any time received by it pursuant to any of the provisions of this Agreement or of the Warrant Certificates. 

(g)    No Liability for Invalidity. The Warrant Agent shall have no liability with respect to any invalidity of
this Agreement or any of the Warrant Certificates (except as to the Warrant Agent’s countersignature thereon). 

(h)    No Responsibility for Representations. The Warrant Agent shall not be responsible for any of the recitals or
representations herein or in the Warrant Certificates (except as to the Warrant Agent’s countersignature thereon), all of which are made solely by the Company. 

(i)    No Implied Obligations. The Warrant Agent shall be obligated to perform only such duties as are herein and
in the Warrant Certificates specifically set forth and no implied duties or obligations shall be read into this Agreement or the Warrant Certificates against the Warrant Agent. The Warrant Agent shall not be under any obligation to take any action
hereunder which may tend to involve it in any expense or liability, the payment of which within a reasonable time is not, in its reasonable opinion, assured to it. The Warrant Agent shall not be accountable or under any duty or responsibility for
the use by the Company of any of the Warrant Certificates authenticated by the Warrant Agent and delivered by it to the Company pursuant to this Agreement or for the application by the Company of the proceeds of the Warrant Certificates. The Warrant
Agent shall have no duty or responsibility in case of any default by the Company in the performance of its covenants or agreements contained herein or in the Warrant Certificates or in the case of the receipt of any written demand from a Holder of a
Warrant Certificate with respect to such default, including, without limiting the generality of the foregoing, any duty or responsibility to initiate or attempt to initiate any proceedings at law. 

  
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 Section 15.    Purchase or Consolidation or Change of Name of Warrant
Agent. Any corporation into which the Warrant Agent or any successor Warrant Agent may be merged or with which it may be consolidated, or any corporation resulting from any merger or consolidation to which the Warrant Agent or any successor
Warrant Agent shall be party, or any corporation succeeding to the corporate trust business of the Warrant Agent or any successor Warrant Agent, shall be the successor to the Warrant Agent under this Agreement without the execution or filing of any
paper or any further act on the part of any of the parties hereto, provided that such corporation would be eligible for appointment as a successor Warrant Agent under the provisions of Section 17. In case at the time such successor Warrant
Agent shall succeed to the agency created by this Agreement any of the Warrant Certificates shall have been countersigned but not delivered, any such successor Warrant Agent may adopt the countersignature of the predecessor Warrant Agent and deliver
such Warrant Certificates so countersigned; and in case at that time any of the Warrant Certificates shall not have been countersigned, any successor Warrant Agent may countersign such Warrant Certificates either in the name of the predecessor
Warrant Agent or in the name of the successor Warrant Agent; and in all such cases such Warrant Certificates shall have the full force provided in the Warrant Certificates and in this Agreement. 

In case at any time the name of the Warrant Agent shall be changed and at such time any of the Warrant Certificates shall have been
countersigned but not delivered, the Warrant Agent may adopt the countersignature under its prior name and deliver Warrant Certificates so countersigned; and in case at that time any of the Warrant Certificates shall not have been countersigned, the
Warrant Agent may countersign such Warrant Certificates either in its prior name or in its changed name; and in all such cases such Warrant Certificates shall have the full force provided in the Warrant Certificates and in this Agreement. 

Section 16.    Duties of Warrant Agent. The Warrant Agent undertakes the duties and obligations imposed by
this Agreement upon the following terms and conditions, by all of which the Company, by its acceptance hereof, shall be bound: 
 (a)
    The Warrant Agent may consult with legal counsel reasonably acceptable to the Company (who may be legal counsel for the Company), and the opinion of such counsel shall be full and complete authorization and protection to the
Warrant Agent as to any action taken or omitted by it in good faith and in accordance with such opinion. 

  
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 (b)     Whenever in the performance of its duties under this Agreement the
Warrant Agent shall deem it necessary or desirable that any fact or matter be proved or established by the Company prior to taking or suffering any action hereunder, such fact or matter (unless other evidence in respect thereof be herein
specifically prescribed) may be deemed to be conclusively proved and established by a certificate signed by the Chief Executive Officer, Chief Financial Officer or Vice President of the Company; and such certificate shall be full authentication to
the Warrant Agent for any action taken or suffered in good faith by it under the provisions of this Agreement in reliance upon such certificate. 

(c)     Subject to the limitation set forth in Section 14, the Warrant Agent shall be liable hereunder only for its
own gross negligence or willful misconduct, or for a breach by it of this Agreement. Notwithstanding anything contained herein to the contrary, the Warrant Agent’s aggregate liability during any term of this Agreement with respect to, arising
from, or arising in connection with this Agreement, or from all services provided or omitted to be provided under this Agreement, whether in contract, or in tort, or otherwise, is limited to, and shall not exceed, the amounts paid hereunder by the
Company to Warrant Agent as fees and charges, but not including reimbursable expenses, during the twelve (12) months immediately preceding the event for which recovery from Warrant Agent is being sought. 

(d)     The Warrant Agent shall not be liable for or by reason of any of the statements of fact or recitals contained in
this Agreement or in the Warrant Certificates (except its countersignature thereof) by the Company or be required to verify the same, but all such statements and recitals are and shall be deemed to have been made by the Company only. 

(e)     The Warrant Agent shall not be under any responsibility in respect of the validity of this Agreement or the
execution and delivery hereof (except the due execution hereof by the Warrant Agent) or in respect of the validity or execution of any Warrant Certificate (except its countersignature thereof); nor shall it be responsible for any breach by the
Company of any covenant or condition contained in this Agreement or in any Warrant Certificate; nor shall it be responsible for the adjustment of the Exercise Price or the making of any change in the number of Common Shares required under the
provisions of Section 11 or 13 or responsible for the manner, method or amount of any such change or the ascertaining of the existence of facts that would require any such adjustment or change (except with respect to the exercise of Warrants
evidenced by Warrant Certificates after actual notice of any adjustment of the Exercise Price); nor shall it by any act hereunder be deemed to make any representation or warranty as to the authorization or reservation of any Common Shares to be
issued pursuant to this Agreement or any Warrant Certificate or as to whether any Common Shares will, when issued, be duly authorized, validly issued, fully paid and nonassessable. 

(f)     Each party hereto agrees that it will perform, execute, acknowledge and deliver or cause to be performed,
executed, acknowledged and delivered all such further and other acts, instruments and assurances as may reasonably be required by the other party hereto for the carrying out or performing by any party of the provisions of this Agreement. 

(g)     The Warrant Agent is hereby authorized to accept instructions with respect to the performance of its duties
hereunder from the Chief Executive Officer, Chief Financial Officer or Vice President of the Company, and to apply to such officers for advice or instructions in connection with its duties, and it shall not be liable and shall be indemnified and
held harmless for any action taken or suffered to be taken by it in good faith in accordance with instructions of any such officer, provided Warrant Agent carries out such instructions without gross negligence or willful misconduct. 

(h)     The Warrant Agent and any shareholder, director, officer or employee of the Warrant Agent may buy, sell or deal in
any of the Warrants or other securities of the Company or become pecuniarily interested in any transaction in which the Company may be interested, or contract with or lend money to the Company or otherwise act as fully and freely as though it were
not Warrant Agent under this Agreement. Nothing herein shall preclude the Warrant Agent from acting in any other capacity for the Company or for any other legal entity. 

  
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 (i)     The Warrant Agent may execute and exercise any of the rights or
powers hereby vested in it or perform any duty hereunder either itself or by or through its attorney or agents, and the Warrant Agent shall not be answerable or accountable for any act, default, neglect or misconduct of any such attorney or agents
or for any loss to the Company resulting from any such act, default, neglect or misconduct, provided reasonable care was exercised in the selection and continued employment thereof. 

(j)    The Company shall calculate and transmit to the Warrant Agent, and the Warrant Agent shall have no obligation under
this Agreement to calculate, the applicable ratio for a cashless exercise of Warrants. The number of Common Shares to be issued on such exercise will be determined by the Company (with written notice thereof to the Warrant Agent) and the Warrant
Agent shall have no duty or obligation to investigate or confirm whether the Company’s determination of the number of such Common Shares to be issued on such exercise is accurate or correct. 

(k)    The Warrant Agent shall forward funds received for Warrant exercises in a given month by the 5th Business Day of the following month by wire transfer to an account designated by the Company. 

(l)    In the event of a cashless exercise, the Company shall provide a cost basis for the Common Shares issued pursuant
thereto to the Warrant Agent. 
 (j)    From time to time, Company may provide the Warrant Agent with instructions
concerning the services performed by the Warrant Agent hereunder. In addition, at any time Warrant Agent may apply to any officer of Company for instruction, and may consult with legal counsel for Warrant Agent or Company with respect to any matter
arising in connection with the services to be performed by the Warrant Agent under this Agreement. Warrant Agent and its agents and subcontractors shall not be liable and shall be indemnified by Company for any action taken or omitted by Warrant
Agent in reliance upon any Company instructions or upon the advice or opinion of such counsel. Warrant Agent shall not be held to have notice of any change of authority of any person, until receipt of written notice thereof from Company. The last
two sentences of this subparagraph shall survive termination or removal of the Warrant Agent. 
 Section 17.
    Change of Warrant Agent. The Warrant Agent may resign and be discharged from its duties under this Agreement upon 30 days’ notice in writing sent to the Company and to each transfer agent of the Common Shares, and
to the Holders of the Warrant Certificates. The Company may remove the Warrant Agent or any successor Warrant Agent upon 30 days’ notice in writing, sent to the Warrant Agent or successor Warrant Agent, as the case may be, and to each transfer
agent of the Common Shares, and to the Holders of the Warrant Certificates. If the Warrant Agent shall resign or be removed or shall otherwise become incapable of acting, the Company shall appoint a successor to the Warrant Agent. If the Company
shall fail to make such appointment within a period of 30 days after such removal or after it has been notified in writing of such resignation or incapacity by the resigning or incapacitated Warrant Agent or by the Holder of a Warrant Certificate
(who shall, with such notice, submit his Warrant Certificate for inspection by the Company), then the Holder of any Warrant Certificate may apply to any court of competent jurisdiction for the appointment of a new Warrant Agent, provided that, for
purposes of this Agreement, the Company shall be deemed to be the Warrant Agent until a new warrant agent is appointed. Any successor Warrant Agent, whether appointed by the Company or by such a court, shall be a corporation organized and doing
business under the laws of the United States or of a state thereof, in good standing, which is authorized under such laws to exercise corporate trust powers and is subject to supervision or examination by federal or state authority and which has at
the time of its appointment as Warrant Agent a combined capital and surplus of at least $50,000,000. After appointment, the successor Warrant Agent shall be vested with the same powers, rights, duties and responsibilities as if it had been
originally named as Warrant Agent without further act or deed; but the predecessor Warrant Agent shall deliver and transfer to the successor Warrant Agent any property at the time held by it hereunder, and execute and deliver any further assurance,
conveyance, act or deed necessary for the purpose. Not later than the effective date of any such appointment, the Company shall file notice thereof in writing with the predecessor Warrant Agent and each transfer agent of the Common Shares, and mail
a notice thereof in writing to the Holders of the Warrant Certificates. However, failure to give any notice provided for in this Section 17, or any defect therein, shall not affect the legality or validity of the resignation or removal of the
Warrant Agent or the appointment of the successor Warrant Agent, as the case may be. 
 Section 18.     Issuance
of New Warrant Certificates. Notwithstanding any of the provisions of this Agreement or of the Warrants to the contrary, the Company may, at its option, issue new Warrant Certificates evidencing Warrants in such form as may be approved by its
Board of Directors to reflect any adjustment or change in the Exercise Price per share and the number or kind or class of shares or other securities or property purchasable under the several Warrant Certificates made in accordance with the
provisions of this Agreement. 

  
 14 








 Section 18.     Bank Accounts. All funds received by Computershare
under this Agreement that are to be distributed or applied by Computershare in the performance of its services hereunder (the “Funds”) shall be held by Computershare as agent for the Company and deposited in one or more bank accounts to be
maintained by Computershare in its name as agent for the Company. Until paid pursuant to the terms of this Agreement, Computershare will hold the Funds through such accounts in: deposit accounts of commercial banks with Tier 1 capital exceeding $1
billion or with an average rating above investment grade by S&P (LT Local Issuer Credit Rating), Moody’s (Long Term Rating) and Fitch Ratings, Inc. (LT Issuer Default Rating) (each as reported by Bloomberg Finance L.P.). Computershare shall
have no responsibility or liability for any diminution of the Funds that may result from any deposit made by Computershare in accordance with this paragraph, including any losses resulting from a default by any bank, financial institution or other
third party. Computershare may from time to time receive interest, dividends or other earnings in connection with such deposits. Computershare shall not be obligated to pay such interest, dividends or earnings to the Company, any holder or any other
party. 
 Section 19.     Notices. Notices or demands authorized by this Agreement to be given or made
(i) by the Warrant Agent or by the Holder of any Warrant Certificate to or on the Company, (ii) subject to the provisions of Section 17, by the Company or by the Holder of any Warrant Certificate to or on the Warrant Agent or
(iii) by the Company or the Warrant Agent to the Holder of any Warrant Certificate, shall be deemed given (a) on the date delivered, if delivered personally, (b) on the first Business Day following the deposit thereof with Federal
Express or another recognized overnight courier, if sent by Federal Express or another recognized overnight courier, (c) on the fourth Business Day following the mailing thereof with postage prepaid, if mailed by registered or certified mail
(return receipt requested), and (d) the date of transmission, if such notice or communication is delivered via facsimile or email attachment at or prior to 5:30 p.m. (New York City time) on a Business Day and (e) the next Business Day
after the date of transmission, if such notice or communication is delivered via facsimile or email attachment on a day that is not a Business Day or later than 5:30 p.m. (New York City time) on any Business Day, in each case to the parties at the
following addresses (or at such other address for a party as shall be specified by like notice): 
 (a)    If to the
Company, to: 
 (b)    If to the Warrant Agent, to: 

For any notice delivered by email to be deemed given or made, such notice must be followed by notice sent by overnight courier service to be
delivered on the next business day following such email, unless the recipient of such email has acknowledged via return email receipt of such email. 

(c)     If to the Holder of any Warrant Certificate, to the address of such Holder as shown on the registry books of the
Company. Any notice required to be delivered by the Company to the Holder of any Warrant may be given by the Warrant Agent on behalf of the Company. Notwithstanding any other provision of this Agreement, where this Agreement provides for notice of
any event to a Holder of any Warrant, such notice shall be sufficiently given if given to the Depositary (or its designee) pursuant to the procedures of the Depositary or its designee. 

Section 20.     Supplements and Amendments. 

(a)     The Company and the Warrant Agent may from time to time supplement or amend this Agreement without the approval of
any Holders of Global Warrants or Warrant certificates in order to add to the covenants and agreements of the Company for the benefit of the Holders of the Global Warrants or Warrant Certificates or to surrender any rights or power reserved to or
conferred upon the Company in this Agreement, provided that such addition or surrender shall not adversely affect the interests of the Holders of the Global Warrants or Warrant Certificates in any material respect. 

  
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 (b)    In addition to the foregoing, with the consent of Holders of Warrants
entitled, upon exercise thereof, to receive not less than a majority of the Common Shares issuable thereunder, the Company and the Warrant Agent may modify this Agreement for the purpose of adding any provisions to or changing in any manner or
eliminating any of the provisions of this Warrant Agreement or modifying in any manner the rights of the Holders of the Global Warrants; provided, however, that no modification of the terms (including but not limited to the adjustments
described in Section 11) upon which the Warrants are exercisable or the rights of holders of Warrants to receive liquidated damages or other payments in cash from the Company or reducing the percentage required for consent to modification of
this Agreement may be made without the consent of the Holder of each outstanding warrant certificate affected thereby; provided further, however, that no amendment hereunder shall affect any terms of any Warrant Certificate
issued in a Warrant Exchange. As a condition precedent to the Warrant Agent’s execution of any amendment, the Company shall deliver to the Warrant Agent a certificate from a duly authorized officer of the Company that states that the proposed
amendment complies with the terms of this Section 20. 
 Section 21.    Successors. All covenants and
provisions of this Agreement by or for the benefit of the Company or the Warrant Agent shall bind and inure to the benefit of their respective successors and assigns hereunder. 

Section 22.    Benefits of this Agreement. Nothing in this Agreement shall be construed to give any Person
other than the Company, the Holders of Warrant Certificates and the Warrant Agent any legal or equitable right, remedy or claim under this Agreement. This Agreement shall be for the sole and exclusive benefit of the Company, the Warrant Agent and
the Holders of the Warrant Certificates. 
 Section 23.    Governing Law. This Agreement and each Warrant
Certificate issued hereunder shall be governed by, and construed in accordance with, the laws of the State of New York without giving effect to the conflicts of law principles thereof. 

Section 24.    Counterparts. This Agreement may be executed in any number of counterparts and each of such
counterparts shall for all purposes be deemed to be an original, and all such counterparts shall together constitute but one and the same instrument. 

Section 25.    Captions. The captions of the sections of this Agreement have been inserted for convenience
only and shall not control or affect the meaning or construction of any of the provisions hereof. 

Section 26.    Information. The Company agrees to promptly provide to the Holders of the Warrants any
information it provides to the holders of the Common Shares, except to the extent any such information is publicly available on the EDGAR system (or any successor thereof) of the Securities and Exchange Commission. 

Section 27.    Confidentiality. The Warrant Agent and the Company agree that all books, records, information and
data pertaining to the business of the other party, including inter alia, personal, non-public warrant holder information, which are exchanged or received pursuant to the negotiation or the carrying out of this Agreement including the fees for
services set forth in the attached schedule shall remain confidential, and shall not be voluntarily disclosed to any other person, except as may be required by law, including, without limitation, pursuant to subpoenas from state or federal
government authorities (e.g., in divorce and criminal actions). 
 Section 28.    Further Assurances. The Company
shall perform, acknowledge and deliver or cause to be performed, acknowledged and delivered all such further and other acts, documents, instruments and assurances as may be reasonably required by the Warrant Agent for the carrying out or performing
by the Warrant Agent of the provisions of this Agreement. 
 Section 29.    No Consequential Damages. Neither
party to this Agreement shall be liable to the other party for any consequential, indirect, special or incidental damages under any provisions of this Agreement or for any consequential, indirect, punitive, special or incidental damages arising out
of any act or failure to act hereunder even if that party has been advised of or has foreseen the possibility of such damages. 
 Section
30.    Force Majeure. Notwithstanding anything to the contrary contained herein, the Warrant Agent will not be liable for any delays or failures in performance resulting from acts beyond its reasonable control including,
without limitation, acts of God, terrorist acts, shortage of supply, breakdowns or malfunctions, interruptions or malfunction of computer facilities, or loss of data due to power failures or mechanical difficulties with information storage or
retrieval systems, labor difficulties, war, or civil unrest. 

  
 16 








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

			
	ACASTI PHARMA INC.
		
	By:	 	 
		 	Name:
		 	Title:
		
	By:	 	 
		 	Name:
		 	Title:
	
	COMPUTERSHARE TRUST COMPANY N.A.
		
	By:	 	 
		 	Name:
		 	Title:



  
 17 








 Annex A: Form of Warrant Certificate Request Notice 

WARRANT CERTIFICATE REQUEST NOTICE 

To:
                     as Warrant Agent for
                     (the “Company”) 

The undersigned Holder of Common Share Purchase Warrants (“Warrants”) in the form of Global Warrants issued by the
Company hereby elects to receive a Warrant Certificate evidencing the Warrants held by the Holder as specified below: 
  

	1.	Name of Holder of Warrants in form of Global Warrants:
                                        


  

	2.	Name of Holder in Warrant Certificate (if different from name of Holder of Warrants in form of Global Warrants):
                                        


  

	3.	Number of Warrants in name of Holder in form of Global Warrants:
                                        


  

	4.	Number of Warrants for which Warrant Certificate shall be issued:
                                        


  

	5.	Number of Warrants in name of Holder in form of Global Warrants after issuance of Warrant Certificate, if any:
                                        


  

	6.	Warrant Certificate shall be delivered to the following address: 

  

			
		
	  
	 	   

		
	  
	 	   

		
	  
	 	   

		
	  
	 	   


 The undersigned hereby acknowledges and agrees that, in connection with this Warrant Exchange and the issuance
of the Warrant Certificate, the Holder is deemed to have surrendered the number of Warrants in form of Global Warrants in the name of the Holder equal to the number of Warrants evidenced by the Warrant Certificate. 

[SIGNATURE OF HOLDER] 
 Name of
Investing Entity: 

	
	
	   


 Signature of Authorized Signatory of Investing Entity: 

	
	
	   



  
 18 








 Name of Authorized Signatory: 

	
	
	   


 Title of Authorized Signatory: 

	
	
	   


 Date:
                                         
                                    

  
 19 








 Exhibit 1: Form of Warrant Certificate 

  
 20 








 Exhibit 2: Warrant Agent Compensation 

  
 21