LOCK-UP AGREEMENT (this "Agreement") is entered into as of May 7, 2021 by and between Acasti Pharma Inc.,

LOCK-UP AGREEMENT (this "Agreement") is entered into as of May 7, 2021 by and between Acasti Pharma Inc.,

a corporation incorporated under the Business Corporations Act (Qu bec) ("Acasti"), the undersigned

stockholder (the "Stockholder") of Grace Therapeutics, Inc., a corporation incorporated under the laws of the

State of Delaware ("Grace") [and the undersigned manager or officer of the Stockholder (the "Principal").]

WHEREAS, concurrently

with the execution of this Agreement, Acasti, Grace and Acasti Pharma U.S., Inc., a Delaware corporation and a direct wholly-owned

Subsidiary of Acasti ("MergerCo"), have entered into an Agreement and Plan of Merger (as the same may be amended

from time to time, the "Merger Agreement"), which provides, among other things, that MergerCo will be merged

with and into Grace (the "Merger"), with Grace surviving the Merger as a direct wholly-owned subsidiary of Acasti;

of the date hereof, the Stockholder is the Beneficial Owner or record owner of the number of shares of Class A common stock, par

value $0.0001 per share (the "Grace Shares"), of Grace set forth on the signature page hereof;

Principal exercises direct or indirect control over the Stockholder;]

to the Merger Agreement, at the Effective Time, the Grace Shares held of record or Beneficially Owned by the Stockholder and outstanding

immediately prior to the Effective Time will be converted into the right to receive the number of common shares of Acasti (the

"Acasti Shares") in accordance with the terms of the Merger Agreement;

Merger Agreement is required under Section 251 of the Delaware General Corporation Law (the "DGCL") to be adopted

by the affirmative vote of the holders of a majority of the outstanding Grace Shares entitled to vote on such matter; and

a condition to the willingness of Acasti and MergerCo to enter into the Merger Agreement, and in order to induce Acasti and MergerCo

to enter into the Merger Agreement, the Stockholder has agreed to enter into this Agreement.

in consideration of the premises and of the mutual agreements and covenants set forth herein and in the Merger Agreement and for

other good and valuable consideration, the receipt and adequacy of which are hereby acknowledged, and intending to be legally bound

hereby, the parties hereto agree as follows:

Terms. Capitalized terms used but not defined in this Agreement shall have the meanings ascribed to them in the Merger Agreement.1.2

For purposes of this Agreement:

"Beneficially Own", "Beneficial Ownership" or "beneficial owner"

with respect to any Grace Shares or Acasti Shares, as applicable, means having, or a Person having, "beneficial ownership"

of such securities (as determined pursuant to Rule 13d-3 under the Securities Exchange Act of 1934, as amended (the "Exchange

Act")), including pursuant to any agreement, arrangement or understanding, whether or not in writing, and including,

without duplicative counting of the same securities by the same holder, securities over which Affiliates of such Person who, together

with such Person, would constitute a "group" within the meaning of Section 13(d)(3) of the Exchange Act, have "beneficial

ownership" (as determined pursuant to Rule 13d-3 under the Exchange Act).

"Owned Grace Shares" means, collectively, all (i) Grace Shares held of record or Beneficially Owned by

the Stockholder as of the date hereof and (ii) Grace Shares that become owned (whether Beneficially Owned or of record) by

the Stockholder, whether upon the exercise of stock options, conversion of convertible securities or otherwise, after the execution

TRANSFER AND VOTING OF SCARLET SHARES

2.1 No Transfer of Grace Shares. From and after the date hereof until the Expiration Date (as defined below), the Stockholder

shall not, directly or indirectly, (a) sell, pledge, encumber, assign, transfer or otherwise dispose of any or all of the Owned

Grace Shares or any interest in the Owned Grace Shares, (b) deposit the Owned Grace Shares or any interest in the Owned Grace Shares

into a voting trust or enter into a voting agreement or arrangement with respect to any of his, her or its Owned Grace Shares (other

than this Agreement) or grant any proxy or power of attorney with respect thereto, or (c) enter into any contract, commitment,

option or other arrangement or undertaking with respect to the direct or indirect acquisition or sale, assignment, pledge, encumbrance,

transfer or other disposition (whether by actual disposition or effective economic disposition due to hedging, cash settlement

or otherwise) of any of the Owned Grace Shares (any such action in clause (a), (b) or (c) above, a "transfer");

provided, that this Section 2.1 shall not prohibit a transfer of Owned Grace Shares by the Stockholder if (a) the

Stockholder is an individual, (i) to any member of the Stockholder's immediate family or to a trust for the benefit of the

Stockholder or any member of the Stockholder's immediate family, or (ii) upon the death of the Stockholder, by will or intestacy

or (b) the Stockholder is a partnership or limited liability company, to one or more partners or members of the Stockholder or

to an Affiliate under common control with the Stockholder, as applicable.

of the Merger and Related Matters. The Stockholder, solely in the Stockholder's capacity as a stockholder of Grace (and

not, if applicable, in the Stockholder's capacity as an officer or director of Grace), agrees that:

within five (5) Business Days after the Form S-4 has been declared effective by the SEC, the Stockholder shall deliver a

written consent (or cause a consent to be delivered) covering all of the Owned Grace Shares (the "Written Consent"):

(i) approving the adoption of the Merger Agreement and approval of the Merger and the other transactions contemplated by the Merger

Agreement, and (ii) waiving any notice that may have been or may be required relating to the Merger or any of the other transactions

contemplated by the Merger Agreement (together, the "Stockholder Approval Matters"). The Written Consent shall

be coupled with an interest and shall be irrevocable; and

from and after the date hereof until the Expiration Date (as defined below), in connection with any meeting of the stockholders

of Grace or any adjournment thereof, the Stockholder shall appear at each such meeting or otherwise cause all of the Owned Grace

Shares to be counted as present thereat for purposes of calculating a quorum and vote (or cause to be voted), in person or by proxy,

all of the Owned Grace Shares: (i) in favor of the adoption of the Stockholder Approval Matters, and (ii) except for the Merger

and the Merger Agreement, against any Grace Acquisition Proposal.

The obligations of the Stockholder pursuant to this Article 2 shall terminate upon the earlier to occur of (a) the date

the Merger Agreement shall have been validly terminated pursuant to its terms, (b) in the event of a Grace Change of Recommendation

or an Acasti Change of Recommendation, in any such case in accordance with the terms of the Merger Agreement, and (c) the Effective

Time (such earlier date, the "Expiration Date").

Capacity. The parties acknowledge that this Agreement is entered into by the Stockholder solely in his, her or its capacity

as owner of the Owned Grace Shares and that nothing in this Agreement shall in any way restrict, limit or prohibit the Stockholder

or any Affiliate, designee or representative of the Stockholder from exercising his or her fiduciary duties in his or her capacity

as a director or officer of Grace, whether by action or failure take any action, including, for the avoidance of doubt, exercising

any rights of Grace under the Merger Agreement, and no such exercise of fiduciary duties shall be deemed to constitute a breach

TRANSFER and voting OF Acasti SHARES

3.1 No Transfer of Acasti Shares. During the period beginning from and after the Effective Time and ending on the date

that is the first anniversary of the Effective Time (the "Lock-Up Period"), the Stockholder shall not, directly

or indirectly, without the prior written consent of Acasti, (a) sell, pledge, encumber, assign, transfer or otherwise dispose of

any Acasti Shares or any securities Beneficially Owned by the Stockholder that are convertible into, exercisable or exchangeable

for or that represent the right to receive Acasti Shares, whether now owned or hereafter acquired (collectively, the "Acasti

Securities"), (b) deposit the Acasti Securities or any interest in the Acasti Securities into a voting trust or enter

into a voting agreement or arrangement with respect to any of his, her or its Acasti Securities or grant any proxy or power of

attorney with respect thereto (other than to representative(s) of Acasti in connection with a proxy solicitation made thereby),

or (c) enter into any contract, commitment, option or other arrangement or undertaking with respect to the direct or indirect sale,

assignment, pledge, encumbrance, transfer or other disposition (whether by actual disposition or effective economic disposition

due to hedging, cash settlement or otherwise) of any Acasti Securities (any such action in clause (a), (b) or (c) above, a "transfer");

provided, that this Section 3.1 shall not prohibit a transfer of Acasti Securities by the Stockholder:

(s) if the Stockholder

is an individual, (i) to any member of the Stockholder's immediate family or to a trust for the direct or indirect benefit

of the Stockholder or any member of the Stockholder's immediate family, or (ii) upon the death of the Stockholder, by will

or intestacy; provided that such transfer shall not involve a disposition in exchange for value;

(t) if the Stockholder

is a partnership, limited liability company, corporation, trust or other business entity, (i) to one or more partners, shareholders,

trust beneficiaries or members of the Stockholder, (ii) to an Affiliate of the Stockholder or (iii) to any investment fund or other

entity controlling, controlled by, managing or managed by or under common control with the Stockholder or Affiliates of the Stockholder

(including, for the avoidance of doubt, where the Stockholder is a partnership, to its general partner or a successor partnership

or fund, or any other funds managed by such partnership), as applicable; provided that such transfer shall not involve a

disposition in exchange for value;

(u) to the extent necessary

to produce cash proceeds in the amount required to (I) satisfy any tax obligations of the Stockholder or, in the case of a Stockholder

that is, for U.S. federal income tax purposes, treated as a partnership, grantor trust, disregarded entity, or other pass-through

entity (each, a "Pass-Through Entity"), tax obligations of any direct or indirect owner, member, or beneficiary

of such Pass-Through Entity that arise because of the pass-through treatment of such entity for U.S. federal income tax purposes

and the ownership of such Acasti Securities by such Pass-Through Entity (any such owner, member, or beneficiary a "Tax