Aeterna Zentaris: First Patient Dosed for Phase 3 Registration Trial in Endometrial Cancer with Zoptarelin Doxorubicin (AEZS-108)

All amounts are in U.S. dollars (unless otherwise noted)

QUÉBEC CITY, July 31, 2013 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ: AEZS) (TSX: AEZ) (the "Company") today announced that the first patient has been recruited and dosed for the Phase 3 ZoptEC (Zoptarelin doxorubicin in Endometrial Cancer) trial in women with endometrial cancer resistant to platinum/taxane-based chemotherapy.

"We have reached another important milestone in the final clinical development stage for zoptarelin doxorubicin (AEZS-108) in treating endometrial cancer. Efforts are now focused on pursuing patient recruitment as swiftly as possible", stated David Dodd, President and CEO of Aeterna Zentaris. "This compound's innovative targeted approach potentially offers a much needed novel treatment option for women with endometrial cancer and it provides the Company with a significant market opportunity."

The Study

This is an open-label, randomized, multicenter Phase 3 trial to be conducted in over 120 sites in North America, Europe, Israel and other countries under a Special Protocol Assessment, comparing zoptarelin doxorubicin (AEZS-108) with doxorubicin as second line therapy for locally-advanced, recurrent or metastatic endometrial cancer. Lead investigators are David Scott Miller, MD, from the University of Texas Southwestern Medical Center, in Dallas, Texas, and Hani Gabra, MD, from the Imperial College London Hammersmith Campus in London, England. The trial will involve approximately 500 patients and the primary efficacy endpoint is improvement in median Overall Survival.

Selected as the contract clinical development organization, Ergomed will also assume 30% (up to $10 million) of the clinical and regulatory costs for this trial.

Details for this trial are available at www.clinicaltrials.gov (NCT01767155).

About Zoptarelin Doxorubicin (AEZS-108)

Zoptarelin doxorubicin (AEZS-108) represents a new targeting concept in oncology using a hybrid molecule composed of a synthetic peptide carrier and a well-known chemotherapy agent, doxorubicin. Zoptarelin doxorubicin (AEZS-108)is the first intravenous drug in advanced clinical development that directs the chemotherapy agent specifically to LHRH-receptor expressing tumors, resulting in a more targeted treatment with less damage to healthy tissue. The Company is currently conducting a Phase 3 trial in endometrial cancer under a Special Protocol Assessment, while zoptarelin doxorubicin (AEZS-108) is also in Phase 2 trials for triple-negative breast cancer, prostate cancer and bladder cancer. Aeterna Zentaris owns the worldwide rights to zoptarelin doxorubicin (AEZS-108).

About Endometrial Cancer

Endometrial cancer is the most common gynecologic malignancy and develops when abnormal cells amass to form a tumor in the lining of the uterus. It largely affects women over the age of 50 with a higher prevalence in Caucasians and a higher mortality rate among African Americans. Approximately one in 30 women is diagnosed with endometrial cancer every year. According to the American Cancer Society, an estimated 49,560 new cases of endometrial cancer in the U.S., and 35,600 in Europe, are expected during 2013, with about 20% of recurring disease.

About Aeterna Zentaris

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.

SOURCE Aeterna Zentaris Inc.