6-K

UNITEDSTATES

SECURITIESAND EXCHANGE COMMISSION

Washington,D.C. 20549

FORM6-K

REPORTOF FOREIGN PRIVATE ISSUER

PURSUANTTO RULE 13a-16 OR 15d-16 OF THE SECURITIES EXCHANGE ACT OF 1934

For the month of May 2024

Commission File Number: 001-38064

AeternaZentaris Inc.

(Translation of registrant’s name into English)

c/oNorton Rose Fulbright Canada, LLP,222 Bay Street, Suite 3000,PO Box 53, Toronto ON M5K 1E7, Canada

(Address of principal executive office)

Indicate by check mark whether the registrant files or will file annual reports under cover of Form 20-F or Form 40-F.

Form 20-F ☒ Form 40-F ☐

On May 9, 2024, Aeterna Zentaris Inc. (“Aeterna”) issued a Notice of Meeting and Record Date to NASDAQ and to Canadian Securities Regulatory Authorities. Copies of the Notices of Meeting and Record Date are attached as Exhibits 99.1 and 99.2 and are incorporated herein by reference.

This report on Form 6-K and Exhibits 99.1 and 99.2 included with this report on Form 6-K are hereby incorporated by reference into Aeterna’s Registration Statements on Forms S-8 (No. 333-224737, No. 333-210561 and No. 333-200834) and Form F-3 (No. 333-254680) and shall be deemed to be a part thereof from the date on which this Report on Form 6-K is furnished, to the extent not superseded by documents or reports subsequently filed or furnished.

This report on Form 6-K, including the exhibits attached hereto and incorporated herein by reference, and the information contained herein and therein are not, and do not, constitute an offer to sell any securities or a solicitation of an offer to buy any securities in the United States or any other state or jurisdiction. No sale of securities or solicitation of an offer to buy any securities will be made in the United States or in any state or jurisdiction in which such an offer, solicitation or sale would be unlawful absent registration or qualification under the securities laws thereof. Securities may not be offered or sold in the United States absent registration or an exemption from registration. Any public offering of securities to be made in the United States will be made by means of a prospectus that may be obtained from Aeterna that will contain detailed information about Aeterna and its management, as well as financial statements.

Aeterna has filed a Registration Statement on Form F-1 (including a prospectus) (File No. 333-277115) (the “Form F-1 Registration Statement”) with the U.S. Securities and Exchange Commission (the “SEC”) for the issuance of common share purchase warrants and common shares issuable upon exercise thereof in connection with the previously announced Plan of Arrangement pursuant to which Aeterna will combine with Ceapro Inc. (“Ceapro”), but the Form F-1 Registration Statement has not yet become effective. The common share purchase warrants and common shares issuable upon the exercise thereof may not be sold nor may offers to buy them be accepted prior to the time the Form F-1 Registration Statement becomes effective. Before you invest in any Aeterna common shares, you should read the prospectus in the Form F-1 Registration Statement and the other documents incorporated by reference therein for more complete information about Aeterna, Ceapro, the Plan of Arrangement and the common share purchase warrant offering.

You may get copies of the Form F-1 Registration Statement for free by visiting EDGAR on the SEC website at www.sec.gov or at SEDAR+ at www.sedarplus.ca. Alternatively, you may obtain copies of them by contacting the following:

Media Contact

Joel Shaffer

FGS Longview

[email protected]

416-670-6468

NoOffer or Solicitation

This Report on Form 6-K and the exhibits attached hereto and incorporated by reference herein, and the information contained herein and therein are not, and do not, constitute an offer to sell any securities or a solicitation of an offer to buy any securities in the United States or any other state or jurisdiction, nor shall any securities of Aeterna be offered or sold in any jurisdiction in which such an offer, solicitation or sale would be unlawful. Neither the SEC nor any state securities commission has approved or disapproved of the transactions described herein or determined if this communication is truthful or complete. Any representation to the contrary is a criminal offense.

You should not construe the contents of this Report on Form 6-K or the exhibit attached hereto and incorporated herein by reference as legal, tax, accounting or investment advice or a recommendation. You should consult your own counsel and tax and financial advisors as to legal and related matters concerning the matters described herein.

Forward-LookingStatements

The information in this Report on Form 6-K and the exhibits attached hereto and incorporated herein by reference include forward-looking statements within the meaning of the U.S. Private Securities Litigation Reform Act of 1995, specifically Section 27A of the U.S. Securities Act of 1933, as amended, and Section 21E of the U.S. Securities Exchange Act of 1934, as amended. These forward-looking statements involve a number of known and unknown risks, uncertainties and other factors that could actual results and outcomes to be materially different from historical results or from any future results expressed or implied by such forward-looking statements.

Forward-looking statements include, but are not limited to, the ability of Aeterna and Ceapro to successfully consummate the Plan of Arrangement pursuant to the Arrangement Agreement, dated as of December 14, 2023, between Aeterna and Ceapro with respect thereto within the time expected or at all and, if completed, the anticipated benefits and synergies as well as the assets, cost structure, financial position, cash flows and growth prospects of the combined company.

Risks and factors that could cause actual results or outcomes to differ materially from expectations include, among others, the following:

Additional risk factors that could cause actual results to differ materially include those risks identified in Item 3. “Key Information – Risk Factors” contained in Aeterna’s most recent Annual Report on Form 20-F filed with the SEC and its other filings and submissions from time to time, including those containing its quarterly and annual results, with the SEC, which are available on Aeterna’s website located at www.aeterna.com.

Many of these risks and factors are beyond Aeterna’s control. Aeterna cautions you not to place undue reliance on these forward-looking statements. All written and oral forward-looking statements attributable to Aeterna and/or Ceapro, or persons acting on their behalf, are qualified in their entirety by these cautionary statements. Moreover, unless required by law to update these statements, Aeterna will not necessarily update any of these statements after the date hereof, either to conform them to actual results or to changes in their expectation.

DOCUMENTSINDEX

SIGNATURE

Pursuant to the requirements of the Securities Exchange Act of 1934, the registrant has duly caused this report to be signed on its behalf by the undersigned, thereunto duly authorized.

Exhibit 99.1

May 9, 2024	<br><br> <br>1500<br> Robert-Bourassa Blvd., 7th Floor<br><br> <br>Montreal QC, H3A 3S8<br><br> <br>www.computershare.com
To:<br> NASDAQ
Subject: Aeterna Zentaris Inc.

Dear Sir/Madam:

We advise of the following with respect to the upcoming Meeting of Security Holders for the subject Issuer:

Exhibit 99.2

May<br> 9, 2024	<br><br><br> <br>1500<br>Robert-Bourassa Blvd., 7th Floor<br><br> <br>Montreal QC, H3A 3S8<br><br> <br>www.computershare.com
To:<br> All Canadian Securities Regulatory Authorities
Subject: Aeterna Zentaris Inc.

Dear Sir/Madam:

We advise of the following with respect to the upcoming Meeting of Security Holders for the subject Issuer: