AMENDMENT TO ARRANGEMENT AGREEMENT This amendment (the " Amendment ") is made as of the 16 th day of January, 2024, BETWEEN: CEAPRO INC. , a corporation existing under the federal laws of Canada (" Ceapro "); AND: AETERN

TO ARRANGEMENT AGREEMENT

amendment (the "Amendment") is made as of the 16th day of January, 2024,

INC., a corporation existing under the federal laws of Canada ("Ceapro");

ZENTARIS INC., a corporation existing under the federal laws of Canada ("Aeterna Zentaris")

Ceapro and Aeterna Zentaris (the "Parties") entered into an arrangement agreement dated December 14, 2023 (the

"Arrangement Agreement") setting out the terms and conditions of a plan of arrangement (as amended from time to time,

the "Plan of Arrangement") which provides for, among other things, and subject to the terms and conditions thereof

(i) the acquisition by Aeterna Zentaris of all of the issued and outstanding common shares in the share capital of Ceapro (the "Shares")

from the shareholders of Ceapro (the "Shareholders"), which Shares will be exchanged for common shares of Aeterna

Zentaris (the "Aeterna Zentaris Shares") at the exchange ratio (the "Exchange Ratio") set forth

in the Arrangement Agreement, and (ii) the replacement of each of the outstanding options to purchase Shares granted under or otherwise

subject to the 2023 amended and restated stock option plan of the Corporation approved by the Shareholders on June 6, 2023, as amended

from time to time, for replacement options allowing their holders to acquire Aeterna Zentaris Shares on similar terms, as adjusted by

the Exchange Ratio, by way of a statutory plan of arrangement (the "Arrangement") under Section 192 of the Canada

Business Corporations Act, a copy of which is attached as Schedule A to the Arrangement Agreement;

WHEREAS on the date hereof the Parties wish to amend the Plan of Arrangement in accordance with Section 5.01(a) of the Plan of Arrangement;

THEREFORE THIS AMENDMENT WITNESSES THAT in consideration of the respective covenants and agreements of the Parties herein contained

and for other good and valuable consideration (the receipt and sufficiency of which are hereby acknowledged), the Parties agree as follows:

Amended and Restated Plan of Arrangement

Parties hereby agree to replace the Plan of Arrangement in its entirety by the amended and restated Plan of Arrangement attached hereto

Parties hereby confirm that the Arrangement Agreement remains in full force and effect, unamended, other than as provided in Section

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WITNESS WHEREOF this Amendment has been executed by the Parties as of the date first above written.

BUSINESS CORPORATIONS ACT

DEFINITIONS AND INTERPRETATION

this Plan of Arrangement, any capitalized term used herein and not defined in this Section 1.01 shall have the meaning ascribed thereto

in the Arrangement Agreement. Unless the context otherwise requires, the following words and terms with the initial letter or letters

thereof capitalized shall have the meanings ascribed to them below:

addition, words and phrases used herein and defined in the CBCA and not otherwise defined herein shall have the same meaning herein as

in the CBCA unless the context otherwise requires.

1.02 Interpretation Not Affected by Headings

division of this Plan of Arrangement into Articles, Sections, paragraphs and the insertion of headings are for convenience of reference

only and shall not affect in any way the meaning or interpretation of this Plan of Arrangement. Unless the contrary intention appears,

references in this Plan of Arrangement to an Article, Section or paragraph by number or letter or both refer to the Article, Section

or paragraph, respectively, bearing that designation in this Plan of Arrangement.

1.03 Number, Gender and Persons

this Plan of Arrangement, unless the context otherwise requires, words importing the singular shall include the plural and vice versa,

words importing gender include all genders and the word person and words importing persons shall include a natural person, firm, trust,

partnership, association, corporation, joint venture or government (including any governmental agency, political subdivision or instrumentality

thereof) and any other entity or group of persons of any kind or nature whatsoever.

1.04 Date for any Action

otherwise expressly stated, if the date on or by which any action is required or permitted to be taken hereunder by a Party is not a

Business Day, such action shall be required or permitted to be taken on the next succeeding day which is a Business Day.

1.05 Statutory References

reference to a statute refers to such statute, or successor thereto, and all rules, resolutions and regulations made under it, or its

successor, respectively, as it or its successor, or they, may have been or may from time to time be amended or re-enacted, unless stated

otherwise stated, all references herein to sums of money are expressed in lawful money of the United States and "$" or "USD$"

refers to United States dollars.

Plan of Arrangement shall be governed, including as to validity, interpretation and effect, by the laws of the Province of Alberta and

the laws of Canada applicable therein. All questions as to the interpretation or application of this Plan of Arrangement and all proceedings

taken in connection with the Plan of Arrangement shall be subject to the exclusive jurisdiction of the Court.

2.01 Arrangement Agreement

Plan of Arrangement is made pursuant to, and is subject to the provisions of, and forms part of, the Arrangement Agreement. If there

is any inconsistency or conflict between the provisions of this Plan of Arrangement and the provisions of the Arrangement Agreement,

the provisions of this Plan of Arrangement shall govern.

Plan of Arrangement constitutes an arrangement as referred to in section 192 of the CBCA. The Arrangement will become effective at, and

be binding at and after, the times referred to in Section 2.04 of this Plan of Arrangement on: (i) Ceapro; (ii) Aeterna Zentaris (iii)

all Ceapro Securityholders (including Dissenting Shareholders); and (iv) the Depositary, without any further act or formality required

on the part of any person, except as expressly provided herein.

2.03 Prior Issuance of Aeterna Zentaris New Warrants

prior to the Effective Date and not through the effect of the filing of the Articles of Arrangement and the issuance of the Certificate

of Arrangement, Aeterna Zentaris shall issue 2,534,424 Aeterna Zentaris New Warrants to the holders of Aeterna Zentaris Shares and the

holders of Aeterna Zentaris Adjusted Warrants.

following events shall occur and shall be deemed to occur sequentially as set out below, and, except as otherwise set forth herein, without

any further authorization, act or formality, in each case, unless stated otherwise, effective as at two-minute intervals starting at

the Effective Time (unless otherwise indicated):

exchange or transfer of securities pursuant to this Plan of Arrangement shall be free and clear of any Liens or other claims of third

parties of any kind.

2.06 No Fractional Consideration

fractional Aeterna Zentaris Shares shall be issued to Former Ceapro Shareholders under this Plan of Arrangement. The number of Aeterna

Zentaris Shares to be issued to Former Ceapro Shareholders shall be rounded down to the nearest whole Aeterna Zentaris Share in the event

that a Former Ceapro Shareholder is entitled to a fractional share without any additional compensation in lieu of such fractional share.

2.07 U.S. Tax Matters

U.S. federal (and applicable state and local) income tax purposes, (i) the Arrangement is intended to be treated as a "reorganization"

within the meaning of Section 368(a) of the Code and (ii) the Arrangement Agreement and this Plan of Arrangement are intended to constitute

a "plan of reorganization" within the meaning of the United States Treasury Regulation Section 1.368-2(g) (clauses (i) and

(ii), collectively, the "Intended U.S. Tax Treatment"). The Parties (i) agree to report consistently with the Intended

U.S. Tax Treatment on their income tax returns, and to not take any position for applicable income tax purposes (whether in the conduct

of an audit, preparation of tax returns, or otherwise; provided that such position shall not preclude a Party from settling or otherwise

resolving an audit) that is inconsistent therewith and (ii) agree to not take any action, or knowingly fail to take any action, if such

action or failure to act would reasonably be expected to prevent the Arrangement from being treated inconsistently with the Intended

registered holder of Ceapro Shares may exercise dissent rights with respect to Ceapro Shares held by such Dissenting Shareholder ("Dissent

Rights"), in connection with the Arrangement pursuant to and in the manner set forth in Section 190 of the CBCA, as modified

by the Interim Order and this Section 3.01; provided that, notwithstanding Section 190(5) of the CBCA, the written objection to

the Arrangement Resolution referred to in Section 190(5) of the CBCA must be received by Ceapro not later than 48 hours (excluding Saturday,

Sundays and statutory holidays in Edmonton, Alberta) prior to the Ceapro Meeting. Each Dissenting Shareholder who duly exercises its

Dissent Rights in accordance with this Section 3.01, shall be deemed to have transferred all Ceapro Shares held by such Dissenting Shareholder

and in respect of which Dissent Rights have been validly exercised, to Ceapro, as provided in Section 2.04(b) of this Plan of Arrangement

and if such Dissenting Shareholder:

3.02 Recognition of Dissenting Shareholders

DELIVERY OF AETERNA ZENTARIS SHARES

4.01 Delivery of Aeterna Zentaris Shares

4.02 Lost Certificates

the event any certificate, that immediately prior to the Effective Time represented one or more outstanding Ceapro Shares that were exchanged

for Aeterna Zentaris Shares in accordance with Section 2.04 of this Plan of Arrangement, shall have been lost, stolen or destroyed, upon

the making of an affidavit of that fact by the holder claiming such certificate to be lost, stolen or destroyed, the Depositary shall

deliver in exchange for such lost, stolen or destroyed certificate, a certificate or DRS Advice representing the Aeterna Zentaris Shares

that such holder is entitled to receive in accordance with Section 2.04 of this Plan of Arrangement. When authorizing such delivery of

certificates or DRS Advice representing Aeterna Zentaris Shares that such holder is entitled to receive in exchange for such lost, stolen