Aeterna Zentaris Announces Transfer of Manufacturing Rights Related to Cetrotide® to Merck KGaA

All amounts are in US dollars (unless otherwise mentioned)

QUÉBEC CITY, April 17, 2013 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ: AEZS) (TSX: AEZ) (the "Company") today announced that its German subsidiary has entered into binding agreements with various partners and licensees with respect to the manufacturing rights and obligations for its Cetrotide^® product. The principal effect of such agreements is to transfer manufacturing rights and to grant a manufacturing license for Cetrotide^® to a subsidiary of Merck KGaA of Darmstadt, Germany ("Merck Serono"), in all jurisdictions. Subject to the satisfaction of customary closing conditions, the transaction is expected to be completed on or about October 1, 2013, at which time Aeterna Zentaris would receive a one-time payment of €2.5 million, or approximately $3.2 million and certain other payments. In addition, the Company has also entered into a transitional services agreement with Merck KGaA under which the Company will, during a 36-month period, provide various transition services to assist Merck KGaA in assuming responsibility for the manufacturing of Cetrotide^® in consideration for the payment of a monthly fee to the Company throughout such period.

Cetrotide^® (cetrorelix acetate for injection) is used to regulate hormone responses in women undergoing infertility treatment. Merck Serono, a leader in the field of fertility treatments, currently markets Cetrotide^® worldwide, excluding Japan.

The Company had previously monetized the royalty stream related to Cetrotide^® in November 2008 in a transaction with HealthCare Royalty Partners L.P. (formerly Cowen Healthcare Royalty Partners L.P.). With the transfer of manufacturing rights to Merck Serono, Aeterna Zentaris remains focused on its Phase 3 trial in endometrial cancer and Phase 2 trials in breast, prostate and bladder cancer with AEZS-108, its upcoming NDA filing for AEZS-130 as an oral diagnostic test for growth hormone deficiency in adults, as well as its earlier-stage oncology compounds, including AEZS-120.

The use of the name "Merck" and "Merck Serono" in this press release refers to Merck KGaA of Darmstadt, Germany. In North America, Merck KGaA operates under the umbrella brand EMD.

About Aeterna Zentaris

Aeterna Zentaris is an oncology and endocrinology drug development company currently investigating treatments for various unmet medical needs. The Company's pipeline encompasses compounds at all stages of development, from drug discovery through to marketed products. For more information please 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.

SOURCE AETERNA ZENTARIS INC.