Aeterna Zentaris Presents Proof-of-Concept for Disorazol Z Cytotoxic Conjugates, such as AEZS-125, in Ovarian Cancer Mouse Model at ENA Symposium

QUÉBEC CITY, CANADA, Nov. 8, 2012 /PRNewswire/ – Aeterna Zentaris Inc.
(NASDAQ: AEZS) (TSX: AEZ) (the ”Company”) today presented encouraging
preclinical results for disorazol Z cytotoxic conjugates, such as
AEZS-125, in ovarian cancer. Results showed the compound’s high
potential for the treatment of luteinizing hormone-releasing hormone
(LHRH) receptor positive tumors. Data were presented by the Company’s
Director of Preclinical Development, Babette Aicher, PhD, during a
poster presentation at the 24(th) EORTC-NCI-AACR (ENA) Symposium on “Molecular Targets and Cancer
Therapeutics”, currently held in Dublin, Ireland. The study is funded
through a grant from the German Ministry of Education and Research.

Juergen Engel, PhD, Aeterna Zentaris President and CEO stated,
“Disorazol Z cytotoxic conjugates such as AEZS-125, are an extension of
our AEZS-108 innovative LHRH receptor targeted platform in oncology.
These encouraging results presented at the ENA Symposium will enable us
to select a specific drug candidate for further preclinical development
expected to start in the first quarter of 2013.”

Conclusions

        --  All conjugates of D-Lys6-LHRH and disorazol Z analyzed,
            demonstrated high potential
            regarding the treatment of LHRH-receptor positive tumors;

        --  For all conjugates, including AEZS-125, proof-of-concept could
            be demonstrated in an
            LHRH-receptor positive A2780 ovarian cancer xenograft model;

        --  Experiments are currently under way addressing:
      o Correlation of tumor LHRH-receptor expression and treatment
        efficacy;
      o Evaluation of additional tumor models, such as endometrium and
        triple-negative breast cancer;
      o Assessment of early safety parameters and orientating acute
        toxicity in rodent models.

The poster, “Highly Potent Cytotoxic Conjugates of Disorazol Z Linked to a
LHRH-Receptor Targeting Peptide such as AEZS-125, Interfere with Cell
Cycle Progression in Human Cancer Cell Lines and Suppress Tumor Growth
in a LHRH-Receptor Positive Ovarian Cancer Xenograft Model“, B. Aicher, T. Schuster, L. Blumenstein, P. Schmidt, H. Irschik, R.
Jansen, R. Mueller, E. Guenther, M. Teifel, can be viewed through this link.

About Disorazol Z Cytotoxic Conjugates such as AEZS-125

AEZS-125 is a disorazol Z (AEZS-137) cytotoxic conjugate linked to a
Luteinizing Hormone-Releasing Hormone (LHRH)-receptor targeting
peptide. Disorazol Z is a novel natural compound isolated from
myxobacterium Sorangium cellulosum with outstanding cytotoxic activity.
Disorazol Z is a macrocyclic polyketide which is available via
fermentation in high yield and purity. Besides tubulin binding,
disorazol Z has pro-apoptotic properties and arrested cancer cells in
G2 stage of the cell cycle at subnanomolar concentrations. Disorazol Z
is an ideal partner for the formation of cytotoxic conjugates with
peptides and proteins to selectively target cancer cells.

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.