Exhibit 4.3

 



•••Industry   Industria Canada Canada Canada Certificate of Amendment Certificat de   modification Canada Business Corporations Act Lol canadienne sur les socletes   par actions AETERNA ZENTARIS INC. Corporate name I Denomination socialc   264271-9 Corporation number I Numcro de societe I HEREBY CERTIFY that the   articles of theJE CERTIFIE que les statuts de Ia societe above-named   corporation are amended undersusmentionnee sont modifies aux termes de   section 178 of the Canada Business !'article 178 de Ia Loi canadienne sur /es   Corporations Act as set out in the attached societes par actions, tel qu'il   est indique dans les articles of amendment. clauses modificatrices   ci-jointes. Virginie Ethier Director I Directeur 2015-11-17 Date of Amendment   (YYYY-MM-DD) Date de modification (MAA-MM-JJ) 


    




 










1+1 Canada   Industry lndustrie Canada Form4 Articles of Amendment Canada Business   Corporations Act (CBCA) (s. 27 or 177) Formulaire 4 Clauses modificatrices   Loi canadienne sur /es socif}tf}s par actions (LCSA) {at1. 27 ou 177)   OJCorporate name Denomination sociale AETERNA ZENTARIS INC. 0Corporntion   number Num<..de Ia societe 264271-9 [}] The articles arc amended as   follows Les statuts sont modifies de Ia fa on sui\lante See attached schedule   I Voir l'annexe ci-jointe [I}Declaration: I cenify that I am a di rector or   an officer of the corporntion. Declaration :J'altestc que jc suis un admi   nistrutcu r o u u n dirigca n t de Ia societe, Original signed by I   Originalsigne par Philip A. Theodore Philip A. Theodore 843-900-3211   M1snpresentalJOft consut•esn ofTcncc and, an s\IJMW\ co1n1t'UCW\. apenan 11   lr•ble-lo • fine not nc.etdm& SSt;QJOt to impnsonman ror ••mn not   atriAIIl\ mon\hs or both (s JI:ts«bon lS4l (lloCiheCIIC'Al s d d·.-empn fauer   sc Mdantion eoN\IIUC me tnft¥Uon l't IQft aulcv IW d«<»J.Uon de   culp.abiJut pal ptocidure tonwTUIR. at patlblt d \ftem.a.'unaJe deGOO rowamol   dt"'mou.ou I"..,.do ca p<tnOS(p&rOIDIIh< 250(I)de lllCSAJ   Y o .lt PfO\Idanllnf""""b'"' nq'"oed b) lhe   CBCA Noto thM bolhlhe CIICA and lhe l'tllu.) A<HIIol\ lluunform.tlull\ IO   be dudosod IO lh•l"'bh<. Ia '"" be Sloml   '"pmon>lonfonn>UO<I bani. nUIIIber IC'IPPIMJ.I9 Vous f ssu des   ......,pl<IMIIIJ cucb par lalCSA-II al•n-quo lalCSA d la l.ol   ""I<> rmsct IMnll ('<WJNJ<IJ pmndl<nl quede lth   ...,..."'""""IJ soiml do"il""   au1"'1>11<. lis .....,,11o<la d.1m II Nnqu.de   '"""cr-"p<ftONids nllmbo IC'/PPlJ.(II9 Canada IC 3069   (2008104) 


    




 










Schedule I   Annexe Amendment Schedules I Annexes-ModHicdon The issued and outstanding   common shares in the capital of the Corporation (each, a Common Share) are   hereby consolidated on the basis of one (1) post-consolidation Common Share   for each one hundred (100) pre-consolidation Common Shares. No   fractionalCommon Shares shall be issued upon the consolidation of the issued   and outstanding Common Shares in accordance with the foregoing. All new   Common Shares to be issued upon the issuance of the Certificate of Amendment   shall be rounded down to the nearest whole number of Common Shares and all   fractional Common Shares to which a registered shareholder would otherwise   become entitled as a result of the consolidation will be aggregated and sold   by the Corporation's transfer agent and registrar on the market, with the net   proceeds therefrom being proportionately distributed to registered   shareholders.