Aeterna Zentaris Presents Positive Efficacy and Safety Data for AEZS-108 in Ovarian Cancer at ASCO Meeting

Encouraging trend observed in overall survival

QUÉBEC CITY, June 7 /PRNewswire-FirstCall/ - Aeterna Zentaris Inc. (TSX: AEZ; Nasdaq: AEZS), (the "Company"), a late-stage drug development company specialized in oncology and endocrine therapy, today announced that it presented positive efficacy and safety data for its doxorubicin targeted conjugate compound, AEZS-108, in ovarian cancer. The presentation was made by Prof. Günter Emons, Chairman, Department of Obstetrics & Gynaecology Georg-August University Göttingen, Germany, during last Saturday's poster session at the American Society of Clinical Oncology (ASCO) Annual Meeting, being held through June 8, 2010 at McCormick Place in Chicago. AEZS-108 is currently in a Phase 2 trial conducted in Europe by the German AGO Study Group (Study AGO-GYN5), in advanced ovarian and endometrial cancer, with final results expected by year-end.

The poster (abstract #5035) entitled, "Phase 2 study of AEZS-108, a targeted cytotoxic LHRH analog, in patients with LHRH receptor positive platinum resistant ovarian cancer", G. Emons, S. Tomov, P. Harter, J. Sehouli, P. Wimberger, A. Staehle, L. C. Hanker, F. Hilpert, P. Dall, and C. Gruendker, for the AGO Study Group, details the use of AEZS-108, a targeted cytotoxic drug in which doxorubicin is linked to (D-Lys(6))-luteinizing hormone-releasing hormone (LHRH), in women with histologically confirmed taxane-pretreated platinum-resistant/refractory LHRH-R positive advanced (FIGO III or IV) or recurrent ovarian cancer. Patients received a recommended dose of 267 mg/m2 by intravenous infusion over 2 hours, with retreatment every 3 weeks, for up to 6 courses. Response rate (RECIST and/or GCIG criteria) was defined as primary endpoint. Secondary endpoints were safety, time-to-progression (TTP) and overall survival (OS).

Results

42 patients with platinum-resistant ovarian cancer entered the study. Efficacy included partial response in 5 patients (11.9%) and stable disease for more than 12 weeks in 11 patients (26.2%). Based on those data, a Clinical Benefit Rate (CBR) of 38% can be estimated. Median time to progression (TTP) and overall survival (OS) were 3.5 months (104 days) and 15.6 months (475 days), respectively.

In all, tolerability of AEZS-108 was good and commonly allowed retreatment as scheduled. Only one patient (2.4%) had a dose reduction, and overall, 25 of 170 (14.7%) courses were given with a delay, including also cases in which delay was not related to toxicity. Severe (Grade 3 or 4) toxicity was mainly restricted to rapidly reversible hematologic toxicity (leukopenia / neutropenia) associated with fever in 3 cases. Good tolerability of AEZS-108 was also reflected with only a few patients with non-hematological toxicities of grade 3 (none with grade 4), including single cases (2.4%) each of nausea, constipation, poor general condition, and an enzyme elevation. No cardiac toxicity was reported.

"The efficacy of AEZS-108 in our study was encouraging, considering that it only included patients resistant to prior platinum- and taxane-based therapies", commented Prof. Günter Emons. "In these patients, a clinical benefit rate of 38% and particularly a median overall survival of over 15 months compare favourably with results for drugs such as topotecan and pegylated liposomal doxorubicin that are currently used in this setting. Furthermore, the safety profile of AEZS-108 was relatively benign with no unexpected findings and in particular, no cardiac toxicity."

Juergen Engel, Ph.D., President and CEO of Aeterna Zentaris added, "With these favourable results in refractory ovarian cancer patients, we are now looking forward to the data of our endometrial cancer study scheduled for the fourth quarter."

    Conclusion

    - AEZS-108 was active and well tolerated in patients with heavily
      pre-treated platinum and taxane resistant ovarian cancer;
    - The safety profile confirmed the dose of 267 mg/m2;
    - Hematological toxicity was rapidly reversible;
    - Non-hematological toxicities were usually limited to lower severity;
    - Tolerability and CBR compare favourably with topotecan and liposomal
      doxorubicin;
    - Overall survival is encouraging as all patients treated with AEZS-108
      were platinum-resistant.

Copies of the abstract and the poster are currently available and can be viewed on-line through the ASCO website: http://www.asco.org/.

About Ovarian Cancer

Ovarian cancer is one of the most common gynaecologic malignancies and the fifth most frequent cause of cancer death in women, with most of the cases occurring in women between 50 and 75 years of age. Overall, ovarian cancer accounts for 4% of all cancer diagnoses in women and 5% of all cancer deaths. Approximately 26,000 new cases and 17,000 deaths from this disease are estimated in the European community every year (Source: Gynaecologic Oncology 2004; 92:819-26). The National Cancer Institute estimates that in 2009, in the United States alone, there were 21,550 news cases of ovarian cancer and 14,600 related deaths. A study of Gordon et al, JCO 2001;19:3312-22, compared pegylated liposomal doxorubicin with topotecan showed overall survival of 13.7 and 13.0 months, respectively, in the total study population and 8.2 and 9.5 months, respectively, in the subgroup of patients with platinum-resistant disease.

About AEZS-108

AEZS-108, a doxorubicin LHRH receptor targeted conjugate, is currently in a Phase 2 trial in advanced ovarian and endometrial cancer for which final results are expected before year-end. AEZS-108 has been granted orphan-drug designation by the FDA and has received a positive opinion for Orphan Medicinal Product designation from the Committee for Orphan Medicinal Products (COMP) of the European Medicines Agency, for the treatment of ovarian cancer.

An Investigational New Drug (IND) in the U.S. is in place for the treatment of bladder cancer.

About Aeterna Zentaris Inc.

Aeterna Zentaris Inc. is a late-stage drug development company specialized in oncology and endocrine therapy. News releases and additional information are available at www.aezsinc.com.

Forward-Looking Statements

This press release contains forward-looking statements made pursuant to the safe harbor provisions of the U.S. Securities Litigation Reform Act of 1995. Forward-looking statements involve known and unknown risks and uncertainties, which 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 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 the 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 except if we are required by a governmental authority or applicable law.

SOURCE AETERNA ZENTARIS INC.