Aeterna Zentaris Presents Preclinical Data for Its Anti-Cancer PI3K/ Erk 1/2 Inhibitor, AEZS-136, at AACR Meeting

AEZS-136 shows synergy and efficacy in human tumor cells

QUÉBEC CITY, April 3, 2012 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ: AEZS) (TSX: AEZ) (the "Company") today announced that a poster on its novel orally active anticancer PI3K/Erk 1/2 inhibitor, AEZS-136, showed the compound's unique inhibition and excellent activity against PI3K and Erk signaling pathways, as well as being well tolerated. The poster titled, "Dual inhibition of PI3K and Erk1/2 shows synergy and efficacy in human tumor cells, either by using drug combinations or novel dual PI3K/Erk inhibitors", I. Seipelt, M. Gerlach, L. Blumenstein, G. Mueller, E. Guenther, J. Engel and M. Teifel, was presented by Irene Seipelt, PhD, Director, Preclinical Development at Aeterna Zentaris, at the American Association for Cancer Research Annual Meeting currently held in Chicago.

Results

The anti-proliferative efficacy of AEZS-136 was evaluated in more than 40 human tumor cell lines including breast, ovary, endometrium, multiple myeloma, lung, melanoma, colon, leukemia and prostate cancer cells. In vitro ADMET properties were also widely assessed, while in vivo pharmacokinetics (PK) and anti-tumor efficacy was explored. AEZS-136 was well tolerated and showed dose-dependent inhibition of human colon tumor growth of up to 72% in a Hct116 mouse model.

Conclusions

• Effective dual targeting of Raf-Mek-Erk and PI3K-Akt pathway
• Unique inhibitor with excellent activity against PI3K and Erk
• Induction of G1 arrest and apoptosis
• Broad anti-proliferative activity in vitro
• Favorable in vitro ADMET and in vivo PK profile
• Well tolerated up to daily doses of 90mg/kg for 4 weeks
• In vivo anti-tumor efficacy after oral administration

Juergen Engel, Ph.D., Aeterna Zentaris' President and CEO, commented, "The preclinical data presented yesterday, confirms that AEZS-136 has a unique advantageous dual PI3K /Erk kinase inhibition profile which could prove to be more efficient than single pathway inhibition. Furthermore, AEZS-136 has shown to be well tolerated. Following these encouraging preclinical data, we are currently moving this promising compound into the clinical development stage."

To consult a copy of the poster, please click here.

About AEZS-136

AEZS-136 is an integral part of the Company's kinase research program comprising the investigation of different compounds for single Erk inhibition, single PI3K inhibition and dual Erk/PI3K kinase inhibition. AEZS-136 selectively inhibits the kinase activity of Erk 1/2 and class 1 PI3Ks, enabling simultaneous inhibition of the Raf-Mek-Erk and the PI3K-Akt signaling cascades. AEZS-136 was discovered using our proprietary compound library and high throughput screening technology.

About Aeterna Zentaris Inc.

Aeterna Zentaris is a late-stage oncology drug development company currently investigating potential treatments for various cancers. The Company's innovative approach of "personalized medicine" means tailoring treatments to a patient's specific condition and to unmet medical needs. Aeterna Zentaris' deep pipeline is drawn from its proprietary discovery unit providing the Company with constant and long-term access to state-of-the-art therapeutic options. 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.