Aeterna Zentaris Announces Pricing of US$15.1 Million Public Offering of Common Shares and Warrants

QUÉBEC CITY, Nov. 20, 2013 - Aeterna Zentaris Inc. (NASDAQ: AEZS) (TSX: AEZ) (the "Company") today announced the pricing of its previously announced public offering of 13.1 million units (the "Offering"), with each unit consisting of one common share and one whole warrant to purchase one common share, at a purchase price of US$1.15 per unit. Each warrant will be exercisable for a period of five years following the issuance thereof at an exercise price of US$1.60 per share. Net proceeds from the Offering are expected to be approximately US$13.7 million, after deducting underwriting commissions and other expenses related to the Offering.

Canaccord Genuity Inc. is acting as the sole book-running manager for the Offering. Maxim Group LLC acted as co-manager for the Offering.

The Offering is expected to close on or about November 25, 2013, subject to customary closing conditions including, but not limited to, the receipt of all necessary regulatory approvals, including the approvals of the Toronto Stock Exchange and the NASDAQ Capital Market.

The Company intends to use the net proceeds from the Offering to continue to fund its ongoing drug development activities, primarily for the advancement of its zoptarelin doxorubicin (AEZS-108) program, secondly for its macimorelin acetate (AEZS-130) program, including the preparation of its commercial launch, as well as for the potential addition of commercialized products to the Company's pipeline, future negative cash flow, general corporate purposes and working capital.

The Offering is being conducted pursuant to the Company's effective shelf registration statement on Form F-10 filed with the U.S. Securities and Exchange Commission (the "SEC"), its corresponding Canadian base shelf prospectus and an exemption from the Autorité des marchés financiers permitting the Company to offer common shares and warrants in the United States. A final prospectus supplement relating to the Offering, along with the accompanying base shelf prospectus, will be filed with the SEC and with the securities regulatory authority in each of the provinces of Canada. Electronic copies of the preliminary and final prospectus supplements and the accompanying base shelf prospectus can be obtained on the SEC's website at www.sec.govor on the SEDAR website maintained by the Canadian Securities Administrators at www.sedar.com. Copies of the final prospectus supplement and the accompanying base shelf prospectus relating to the Offering may be obtained, when available, upon request by contacting Canaccord Genuity Inc., Attention: Syndicate Department, 99 High Street, 12th Floor, Boston, Massachusetts 02110, or by telephone at (617) 371-3900.

This press release does not and shall not constitute an offer to sell or the solicitation of an offer to buy any of the Company's securities, nor shall there be any sale of the Company's securities in any state or jurisdiction in which such offer, solicitation or sale would be unlawful prior to registration or qualification under the securities laws of any such state or jurisdiction.

About Aeterna Zentaris Inc.

Aeterna Zentaris is a specialty biopharmaceutical company engaged in developing novel treatments in oncology and endocrinology. The Company's pipeline encompasses compounds from drug discovery to regulatory approval. For more information, visit www.aezsinc.com.

Forward-Looking Statements

This press release contains forward-looking statements made pursuant to the safe harbour provisions of the U.S. Securities Litigation Reform Act of 1995. Forward-looking statements involve known and unknown risks and uncertainties that could cause the Company's actual results to differ materially from those in the forward-looking statements. Such risks and uncertainties include, among others, the availability of funds and resources to pursue R&D projects, the successful and timely completion of clinical studies, the risk that safety and efficacy data from any of our Phase 3 trials may not coincide with the data analyses from previously reported Phase 1 and/or Phase 2 clinical trials, the ability of the Company to take advantage of business opportunities in the pharmaceutical industry, uncertainties related to the regulatory process and general changes in economic conditions. Investors should consult the Company's quarterly and annual filings with the Canadian and U.S. securities commissions for additional information on risks and uncertainties relating to forward-looking statements. Investors are cautioned not to rely on these forward-looking statements. The Company does not undertake to update these forward-looking statements. We disclaim any obligation to update any such factors or to publicly announce the result of any revisions to any of the forward-looking statements contained herein to reflect future results, events or developments, unless required to do so by a governmental authority or by applicable law.