AEterna Zentaris Announces Positive Preliminary Results for Phase 2 Study with LHRH-Receptor Targeted Cytotoxic Conjugate AEZS-1

AEterna Zentaris Announces Positive Preliminary Results for Phase 2 Study with LHRH-Receptor Targeted Cytotoxic Conjugate AEZS-108 in Ovarian Cancer

    Preliminary evaluation after completion of treatment phase shows that
    primary efficacy endpoint has been met for patients with advanced-stage
    platinum-resistant, taxane-pretreated ovarian cancer.
QUEBEC CITY, Nov. 2 /PRNewswire-FirstCall/ - AEterna Zentaris Inc. (TSX: AEZ; Nasdaq: AEZS) (the "Company"), a global biopharmaceutical company focused on endocrine therapy and oncology, today announced positive efficacy data from a Phase 2 study with its targeted cytotoxic peptide conjugate, AEZS-108 (formerly AN-152), in patients with platinum-resistant and taxane-pretreated ovarian cancer. In a personalized healthcare approach, the study selected patients with tumors expressing LHRH receptors, the key element in the targeting mechanism of AEZS-108. Under coordination by Prof. Gunter Emons, MD, Chairman of the Department of Obstetrics & Gynaecology at the University of Gottingen, Germany, this open-label, multi-center and multi-national Phase 2 study 'AGO-GYN-5' is being conducted by the German AGO Study Group (Arbeitsgemeinschaft Gynakologische Onkologie / Gynaecological Oncology Working Group; www.ago-ovar.de), in cooperation with clinical sites in Europe.

Preliminary Results

All 43 patients with LHRH-receptor positive ovarian cancer who entered study AGO-GYN-5 have completed their study treatment. A preliminary evaluation shows that the study met its primary efficacy endpoint of 5 or more responders in 41 evaluable patients.

Responders, as well as patients with stable disease after completion of treatment with AEZS-108, will now be followed to assess the duration of progression-free survival and, ultimately, overall survival. More detailed analyses, which will also include efficacy data from post-treatment follow-up of the ovarian cancer patients, are currently in preparation and will be presented at forthcoming scientific conferences.

Juergen Engel, Ph.D., AEterna Zentaris President and Chief Executive Officer stated, "We are pleased with the progress of this project. The successful completion of the recruitment and treatment phase and the apparent activity in this difficult group of cancer patients is encouraging. This is the basis we were looking for, in order to take the next steps in the further development of AEZS-108 in gynaecological cancers and possibly also in prostate cancer."

About the AEZS-108 Phase 2 Program

AEZS-108 represents a new targeting concept in oncology using a cytotoxic peptide conjugate which is a hybrid molecule composed of a synthetic peptide carrier and a well-known cytotoxic agent, doxorubicin. The design of this product allows for the specific binding and selective uptake of the cytotoxic conjugate by LHRH-receptor-positive tumors. The binding of AEZS-108 to cancerous cells that express these receptors results in its accumulation and preferential uptake in the malignant tissue.

In a Phase 2 study program entitled, "The antitumoral activity and safety of AEZS-108 (AN-152), a LHRH agonist linked doxorubicin in women with LHRH-receptor positive gynaecological tumors", patients with tumors expressing LHRH receptors are administered an intravenous infusion of 267 mg/m2 of AEZS-108 over a period of 2 hours, every Day 1 of a 21-day (3-week) cycle. The proposed duration of the study treatment is 6, 3-week cycles. Study AGO-GYN-5 is performed with 14 centers of the German Gynaecological Oncology Working Group (AGO; www.ago-ovar.de), in cooperation with 3 clinical sites in Europe.

The program was planned to include up to 82 patients, up to 41 with a diagnosis of platinum-resistant and taxane-pretreated ovarian cancer, and up to 41 with disseminated endometrial cancer. For both indications, patient recruitment was planned in 2 stages with 21 and 20 patients, respectively, and the primary efficacy endpoint at the end of stage 2 was defined as 5 or more patients with partial or complete tumor responses according to Response Evaluation Criteria in Solid Tumors (RECIST) and/or Gynaecologic Cancer Intergroup (GCIG) guidelines. Secondary endpoints include time to progression, survival, toxicity, as well as adverse effects.

About Ovarian and Endometrial 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, Volume 92, Issue 3, March 2004, Pages 819-826).

Cancer of the endometrium is the most common gynaecologic malignancy and accounts for 6% of all cancers in women. The majority of the cases occur in postmenopausal women, with the largest number of women developing their cancers during their sixth decade. Approximately 38,000 new cases and 9,000 deaths from this disease are estimated annually in Europe (Source: Annals of Oncology 15:1149-1150, 2004).

About AEterna Zentaris Inc.

AEterna Zentaris Inc. is a global biopharmaceutical company focused on endocrine therapy and oncology, with proven expertise in drug discovery, development and commercialization. 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.