Conformed SHAREHOLDER RIGHTS PLAN AGREEMENT BETWEEN AETERNA ZENTARIS INC. - and - COMPUTERSHARE TRUST COMPANY OF CANADA, as Rights Agent DATED AS OF MARCH 29 , 2016 TABLE OF CONTENTS ARTICLE 1 INTERPRETATION 2 1.1 Certai

SHAREHOLDER RIGHTS PLAN AGREEMENT

AETERNA ZENTARIS INC.

COMPUTERSHARE TRUST COMPANY OF CANADA,

DATED AS OF MARCH 29, 2016

SHAREHOLDER RIGHTS PLAN AGREEMENT

THIS SHAREHOLDER RIGHTS PLAN AGREEMENT is made as of the 29th day of March, 2016.

A. The Board of Directors has determined that it is advisable to adopt a new shareholder rights plan (the Rights Plan ) to ensure, to the extent possible, that all shareholders of the Corporation are treated fairly in connection with any take-over offer or other acquisition of control of the Corporation.

B. In order to implement the Rights Plan, the Board of Directors has:

(a) authorized and declared a distribution of one right (a Right ) in respect of each Share outstanding at the Record Time;

(b) authorized the issuance of one Right in respect of each Share issued after the Record Time and prior to the earlier of the Separation Time and the Expiration Time; and

(c) authorized the issuance of Rights Certificates to holders of Rights pursuant to the terms and subject to the conditions set forth herein.

C. Each Right entitles the holder thereof, after the Separation Time, to purchase securities of the Corporation pursuant to the terms and subject to the conditions set forth herein.

D. The Corporation desires to appoint Computershare Trust Company of Canada as the Rights Agent to act on behalf of the Corporation, and the Rights Agent is willing to so act, in connection with the issuance, transfer, exchange and replacement of Rights Certificates, the exercise of Rights and other matters referred to herein.

NOW THEREFORE in consideration of the premises and respective agreements set forth herein, the parties hereby agree as follows:

1.1 Certain Definitions

For the purposes of this agreement (the Agreement ), including the recitals hereto, the following terms have the meanings indicated:

a) Acquiring Person shall mean any Person who is at any time after the Effective Date the Beneficial Owner of 20% or more of the outstanding Voting Shares of the Corporation; provided, however, that the term Acquiring Person shall not include:

(i) the Corporation or any corporation controlled by the Corporation;

(ii) any Person who becomes the Beneficial Owner of 20% or more of the outstanding Voting Shares as a result of one or any combination of:

(A) a Voting Share Reduction;

(B) a Permitted Bid Acquisition;

(C) an Exempt Acquisition; or

(D) a Pro Rata Acquisition;

provided, however, that if a Person shall become the Beneficial Owner of 20% or more of the outstanding Voting Shares by reason of one or any combination of a Voting Share Reduction, a Permitted Bid Acquisition, an Exempt Acquisition or a Pro Rata Acquisition, and thereafter becomes the Beneficial Owner of an additional one percent of the Voting Shares then outstanding (otherwise than pursuant to a Voting Share Reduction, a Permitted Bid Acquisition, an Exempt Acquisition or a Pro Rata Acquisition or any combination thereof), then, as of the date that such Person becomes a Beneficial Owner of such additional Voting Shares, such Person shall become an Acquiring Person ; or

(iii) an underwriter or member of a banking or selling group acting in such capacity that becomes the Beneficial Owner of 20% or more of the Voting Shares in connection with a distribution of securities; or

(iv) a Person (a Grandfathered Person ) who is the Beneficial Owner of 20% or more of the outstanding Voting Shares determined as of the Record Time, provided, however, that this exemption shall not be, and shall cease to be, applicable to a Grandfathered Person in the event that such Grandfathered Person shall, after the Record Time, (A) cease to own 20 percent or more of the outstanding Voting Shares, or (B) become the Beneficial Owner of additional Voting Shares that increases its Beneficial Ownership of Voting Shares by more than one percent of the number of Voting Shares outstanding as at the Record

Time, other than through one or any combination of a Voting Share Reduction, a Permitted Bid Acquisition, an Exempt Acquisition or a Pro Rata Acquisition; or

(v) for a period of 10 calendar days after the Disqualification Date (as defined below), any Person who becomes the Beneficial Owner of 20% or more of the outstanding Voting Shares as a result of such Person becoming disqualified from relying on Section 1.1e)(vi) solely because such Person is making or has announced a current intention to make a Take-over Bid, either alone or by acting jointly or in concert with any other Person. For the purposes of this definition, Disqualification Date means the first date of a public announcement of facts indicating that any Person is making, or has announced a current intention to make a Take-over Bid.

b) Affiliate shall mean, when used to indicate a relationship with a specified body corporate, a Person that directly or indirectly through one or more intermediaries controls, or is a body corporate controlled by, or under common control with, such specified body corporate.

c) Amendment Date means any date upon which this Agreement may be amended, restated or superseded in accordance with the terms hereof.

d) Associate shall mean, when used to indicate a relationship with a specified Person, (i) a spouse of that Person, (ii) any Person of the same or opposite sex with whom that Person is living in a conjugal relationship outside marriage, (iii) any relative of that Person if that relative has the same residence as that Person or (iv) any relative of such spouse or other Person referred to in the immediately preceding clauses (i), (ii) or (iii) above, if that relative has the same residence as the specified Person.

e) A Person shall be deemed the Beneficial Owner of, and to have Beneficial Ownership of, and to Beneficially Own :

(i) any securities of which such Person or any of such Person s Affiliates or Associates is owner at law or in equity;

(ii) any securities which the Person or any of such Person s Affiliates or Associates has the right to acquire within 60 days (where such right is exercisable within a period of 60 days whether or not upon the occurrence of a contingency or the making of a payment) pursuant to any Convertible Security, agreement, arrangement, pledge or understanding, whether or not in writing (other than (A) customary agreements with and between underwriters and/or banking group and/or selling group members with respect to a distribution of securities or (B) pledges of securities in the ordinary course of the pledgee s business); and

(iii) any securities that are Beneficially Owned within the meaning of clause (i) or (ii) of this Subsection 1.1e) by any other Person with which such Person is acting jointly or in concert;

provided, however, that a Person shall not be deemed the Beneficial Owner of, or to have Beneficial Ownership of, or to Beneficially Own , any security;

(iv) because such security has been deposited with or tendered to such Person pursuant to a Take-over Bid made by such Person or any of such Person s Affiliates or Associates or any other Person acting jointly or in concert with such Person until such deposited or tendered security is taken up or paid for, whichever shall first occur;

(v) because such security has been agreed to be deposited with or tendered to such Person pursuant to a Lock-up Agreement until such deposited or tendered security is taken up or paid for, whichever shall first occur;

(vi) because such Person or any of the Affiliates or Associates of such Person or any other Person referred to in clause 1.1e)(iii) above holds such security provided that: (A) the ordinary business of any such Person (the Fund Manager ) includes the management of pension, mutual, pooled or investment funds for others and such security is held by the Fund Manager in the ordinary course of such business in the performance of such Fund Manager s duties for the account of any other Person (a Client ), including non-discretionary accounts held on behalf of a Client by a broker or dealer registered under applicable laws; (B) such Person (the Trust Company ) is licensed to carry on the business of a trust company under applicable laws and, as such, acts as trustee or administrator or in a similar capacity in relation to the estates of deceased or incompetent Persons (each, an Estate Account ) or in relation to other accounts (each an Other Account ) and holds such security in the ordinary course of such duties for such Estate Accounts or for such Other Accounts; (C) such Person (the Plan Administrator ) is the administrator or the trustee of one or more pension funds or plans (a Plan ) registered under the laws of Canada or any province thereof or the laws of the United States of America or any state thereof and such security is held by the Plan Administrator or the Plan in the ordinary course of such Plan Administrator s or Plan s activities; (D) such Person (the Statutory Body ) is established by statute for purposes that include, and the ordinary business or activity of such Person includes, the management of investment funds for employee benefit plans, pension plans or insurance plans of various public bodies and such security is held by the Statutory Body in the ordinary course of the management of such investment funds; (E) such Person (the Crown Agent ) is acting as an agent of the Crown for purposes that include, and the ordinary business or activity of such Person includes, the management of public assets and such security is held by the Crown Agent in the ordinary course of the management of such public assets; or (F) such Person is a Plan and such security is held by the Plan in the ordinary course of such Plan s activities; provided, however, that in any of the foregoing cases the Fund Manager, the Trust Company, the Plan Administrator, the Statutory Body, the Crown Agent or the Plan, as the case may be, is not then making or has not then announced a current intention to make a Take-over Bid, alone or by acting jointly or in concert with

any other Person, other than an Offer to Acquire Voting Shares or other securities (x) pursuant to a distribution by the Corporation or (y) by means of a Permitted Bid or (z) by means of market transactions made in the ordinary course of business of such Person (including pre-arranged trades entered into in the ordinary course of business of such Person) executed through the facilities of a stock exchange or organized over-the-counter-market;

(vii) because such Person is a Client of the same Fund Manager as another Person on whose account the Fund Manager holds such security, or because such Person is an Estate Account or an Other Account of the same Trust Company as another Person on whose account the Trust Company holds such security, or because such Person is a Plan with the same Plan Administrator as another Plan on whose account the Plan Administrator holds such security;

(viii) because such Person is a Client of a Fund Manager and such security is owned at law or in equity by the Fund Manager, or because such Person is an Estate Account or an Other Account of a Trust Company and such security is owned at law or in equity by the Trust Company, or because such Person is a Plan and such security is owned at law or in equity by the Plan Administrator; or

(ix) because such Person is the registered holder of securities as a result of carrying on the business of, or acting as, a nominee of a securities depository.

For purposes of this Agreement, in determining the percentage of the outstanding Voting Shares with respect to which a Person is, or is deemed to be, the Beneficial Owner, any unissued Voting Shares as to which such Person is deemed the Beneficial Owner pursuant to this Subsection 1.1(e) shall be deemed outstanding.

f) Board of Directors shall mean the board of directors of the Corporation or any duly constituted and empowered committee thereof.

g) Business Day shall mean any day, other than a Saturday or Sunday or a day on which banking institutions in Montreal, Quebec are authorized or obligated by law to close.

h) Canada Business Corporations Act shall mean the Canada Business Corporations Act (Canada), R.S.C. 1985, c. C-44, as amended and the regulations thereunder, as from time to time in effect.

i) Canadian Dollar Equivalent of any amount which is expressed in United States dollars shall mean on any date the Canadian dollar equivalent of such amount determined by reference to the U.S. - Canadian Exchange Rate in effect on such date.

j) Close of Business on any date means the time on such date (or, if such date is not a Business Day, the time on the next succeeding Business Day) at which the office of the transfer agent for the Common Shares in the City of Montreal, Quebec (or, after the Separation Time, the office of the Rights Agent in the City of Montreal, Quebec) is closed to the public; provided, however, that for the purposes of the definition of

Competing Permitted Bid and the definition of Permitted Bid , Close of Business on any date means 11:59 p.m. (local time, at the place of deposit) on such date (or, if such date is not a Business Day, 11:59 p.m. (local time, at the place of deposit) on the next succeeding Business Day).

k) Competing Permitted Bid means a Take-over Bid that:

(i) is made after a Permitted Bid or another Competing Permitted Bid (each such Permitted Bid or Competing Permitted Bid being in this definition, the Prior Bid ) has been made and prior to the expiry, termination or withdrawal of that Prior Bid;

(ii) satisfies all the provisions of the definition of a Permitted Bid other than the requirements set out in Clauses 1.1ff)(ii)(A)i. of the definition of Permitted Bid ; and

(iii) contains, and the take-up and payment for securities deposited or tendered thereunder are subject to, an irrevocable and unqualified condition that no Voting Shares and/or Convertible Securities shall be taken up or paid for pursuant to the Take-over Bid prior to the Close of Business on the last day of the minimum initial deposit period that such Take-over Bid must remain open for deposits of securities thereunder pursuant to MI 62-104 after the date of the Take-over Bid constituting the Competing Permitted Bid,

provided, however, that a Take-over Bid that qualified as a Competing Permitted Bid shall cease to be a Competing Permitted Bid at any time and as soon as such time as when such Take-over Bid ceases to meet any or all of the provisions of this definition and any acquisition of Voting Shares and/or Convertible Securities made pursuant to such Take-over Bid that qualified as a Competing Permitted Bid, including any acquisition of Voting Shares and/or Convertible Securities made before such Take-over Bid ceased to be a Competing Permitted Bid, will not be a Permitted Bid Acquisition.

l) controlled : a body corporate is controlled by another Person or two or more Persons acting jointly or in concert if and only if:

(i) securities entitled to vote in the election of directors carrying more than 50% of the votes for the election of directors are held, directly or indirectly, by or for the benefit of the other Person or two or more Persons acting jointly or in concert; and

(ii) the votes carried by such securities are entitled, if exercised, to elect a majority of the board of directors of such body corporate;

and controls , controlling under common control with shall be interpreted accordingly.

m) Convertible Security means, with respect to any security, a security convertible into or exercisable or exchangeable for the first-mentioned security, including, without

limitation, convertible preferred shares, convertible or exchangeable debt securities, share purchase rights, exchange rights, options and warrants.

n) Co-Rights Agents shall have the meaning ascribed thereto in Subsection 4.1(a).

o) Disposition Date shall have the meaning ascribed thereto in Subsection 5.1(b).

p) Effective Date shall mean 5:01 p.m. on March 29, 2016.

q) Election to Exercise shall have the meaning ascribed thereto in Subsection 2.2(d).

r) Exempt Acquisition means a share acquisition (i) in respect of which the Board of Directors has waived the application of Section 3.1 pursuant to Subsection 5.1(b), 5.1(d) or 5.1(e) or (ii) pursuant to an amalgamation, merger or other statutory procedure requiring shareholder approval.

s) Exercise Price shall mean, as of any date from and after the Separation Time, the price at which a holder of a Right may purchase the securities issuable upon exercise of one whole Right which, subject to adjustment in accordance with the terms hereof, shall be an aggregate dollar amount equal to the Market Price per Share (determined as at the Separation Time) multiplied by five (5).

t) Expiration Time shall mean the earlier of: (i) the Termination Time; and (ii) the Close of Business on the date on which the first annual meeting of shareholders of the Corporation following March 29, 2019 (being the third anniversary of the Effective Date) is held; provided, however, that if the resolution referred to in Section 5.20 is approved by the Independent Shareholders in accordance with Section 5.20 at or prior to the 2019 annual meeting of the Corporation, Expiration Time shall mean the earlier of (A) the Termination Time; and (B) the Close of Business on the date on which the first annual meeting of shareholders of the Corporation following March 29, 2022 (being the sixth anniversary of the Effective Date) is held.

u) Fiduciary shall mean, when acting in that capacity, a trust company registered under the trust company legislation of Canada or any province thereof, a trust company organized under the laws of any state of the United States of America, a portfolio manager registered under the securities legislation of one or more provinces of Canada or an investment adviser registered under the United States Investment Advisers Act of 1940 or any other securities legislation of the United States of America or any state of the United States of America.

v) Flip-in Event shall mean a transaction or event in or pursuant to which any Person becomes an Acquiring Person.

w) holder shall have the meaning ascribed thereto in Section 2.8.

x) Independent Shareholders shall mean holders of outstanding Voting Shares, other than (i) any Acquiring Person or Offeror other than a Person who is deemed not to

Beneficially Own such Voting Shares by reason of clause 1.1e)(vi) hereof; (ii) any Person acting jointly or in concert with any Acquiring Person or Offeror; (iii) any Associate or Affiliate of any Acquiring Person or Offeror; and (iv) any employee benefit plan, stock purchase plan, deferred profit sharing plan and any similar plan or trust for the benefit of employees of the Corporation or a corporation controlled by the Corporation, unless the beneficiaries of the plan or trust direct the manner in which the Voting Shares are to be voted or withheld from voting or direct whether the Voting Shares are to be deposited or tendered to a Take-over Bid.

y) Lock-up Agreement means an agreement between an Offeror or any Affiliate or Associate of an Offeror and one or more holders of Voting Shares (each such holder herein referred to as a Locked-up Person ) who are not Affiliates or Associates of the Offeror and who are not, other than by virtue of entering into such agreement, acting jointly or in concert with the Offeror, the terms of which are publicly disclosed and a copy of which is made available to the public (including the Corporation) not later than the date of the Lock-up Bid (as hereinafter defined) or, if the Lock-up Bid has been made prior to the date of the Lock-up Agreement, not later than the Business Day following the date the Lock-up Agreement was entered into, pursuant to which each Locked-up Person agrees to deposit or tender the Voting Shares held by such holder to a Take-over Bid (the Lock-up Bid ) made by the Offeror or any Affiliates or Associates of the Offeror or any other Person acting jointly or in concert with the Offeror provided that:

(i) the Lock-up Agreement permits the Locked-up Person to withdraw its Voting Shares from the Lock-up Agreement and the Lock-up Bid in order to deposit or tender the Voting Shares to another Take-over Bid or to support another transaction prior to the Voting Shares being taken up and paid for under the Lock-up Bid:

(A) at a price or value per Voting Share that exceeds the price or value per Voting Share offered under the Lock-up Bid; or

(B) for a number of Voting Shares that exceeds by as much as or more than a number specified in the Lock-up Agreement (the Specified Number ) the number of Voting Shares that the Offeror has offered to purchase under the Lock-up Bid at a price or value per Voting Share that is not less than the price or value per Voting Share offered under the Lock-up Bid, provided that the Specified Number is not greater than 7% of the number of Voting Shares offered to be purchased under the Lock-up Bid; or

(C) at such price or value that exceeds by as much as or more than an amount specified in the Lock-up Agreement (the Specified Amount ) the offering price for each Voting Share contained in or proposed to be contained in the Lock-up Bid, provided that the Specified Amount is not greater than 7% of the offering price contained in or proposed to be contained in the Lock-up Bid;

for greater certainty, the Lock-up Agreement may contain a right of first refusal or require a period of delay to give the Person who made the Lock-up Bid an opportunity to match a higher price in another Take-over Bid or transaction or other similar limitation on a Locked-up Person s right to withdraw Voting Shares from the agreement, so long as the limitation does not preclude the exercise by the Locked-up Person of the right to withdraw Voting Shares during the period of the other Take-over Bid or transaction; and

(ii) no break-up fees, topping fees, penalties, expenses or other amounts that exceed in aggregate the greater of:

(A) 2 % of the price or value of the aggregate consideration payable under the Lock-up Bid to a Locked-up Person; and

(B) 50% of the amount by which the price or value of the consideration received by a Locked-up Person under another Take-over Bid or transaction exceeds the price or value of the consideration that the Locked-up Person would have received under the Lock-up Bid;

shall be payable by such Locked-up Person if the Locked-up Person fails to deposit or tender Voting Shares to the Lock-up Bid, or withdraws Voting Shares previously tendered thereto, in order to deposit or tender such Voting Shares to another Take-over Bid or support another transaction.

z) Market Price per security of any securities on any date of determination shall mean the VWAP of such securities for the five consecutive Trading Days through and including the Trading Day immediately preceding such date of determination, provided, however, that (i) if on any such date the securities are not traded on any exchange or in the over-the-counter market, the Market Price per share of such securities on such date shall mean the fair market value per security of the securities on such date as determined by a nationally or internationally recognized investment dealer or investment banker selected by the Board of Directors, and (ii) if the Market Price so determined is expressed in United States dollars, such amount shall be converted to the Canadian Dollar Equivalent.

aa) MI 62-104 means Multilateral Instrument 62-104 - Take-Over Bids and Issuer Bids adopted by certain of the Canadian securities regulatory authorities, as now in effect or as the same may from time to time be amended, re-enacted or replaced and including for greater certainty any successor instrument thereto (including, without limitation, National Instrument 62-104 - Take-Over Bids and Issuer Bids of the Canadian Securities Administrators proposed to come into force on or about May 9, 2016)

bb) Nominee shall have the meaning ascribed thereto in Subsection 2.2(c).

cc) Offer to Acquire shall include:

(i) an offer to purchase or a solicitation of an offer to sell Voting Shares, or a public announcement of an intention to make such an offer or solicitation; and

(ii) an acceptance of an offer to sell Voting Shares, whether or not such offer to sell has been solicited;

or any combination thereof, and the Person accepting an offer to sell shall be deemed to be making an Offer to Acquire to the Person that made the offer to sell.

dd) Offeror shall mean a Person who has announced a current intention to make, or who is making, a Take-over Bid.

ee) Offeror s Securities shall mean the Voting Shares Beneficially Owned on the date of a Take-over Bid by an Offeror.

ff) Permitted Bid means a Take-over Bid that is made by means of a take-over bid circular and that also complies with the following additional provisions:

(i) the Take-over Bid shall be made to all holders of Voting Shares of record (other than the Offeror); and

(ii) the Take-over Bid shall contain, and the provisions for take-up and payment for securities deposited or tendered thereunder shall be subject to, irrevocable and unqualified conditions that:

(A) no Voting Shares and/or Convertible Securities shall be taken up or paid for pursuant to the Take-over Bid:

i. prior to the Close of Business on a date that is not less than 105 days following the date of the Take-over Bid or such shorter minimum period that a take-over bid (that is not exempt from any of the requirements of Division 5 (Bid Mechanics) of MI 62-104) must remain open for deposits of securities thereunder, in the applicable circumstances at such time, pursuant to MI 62-104; and