AEterna Zentaris Presented Positive In Vivo Data On ZEN-019, An Oral, LHRH Antagonist Peptidomimetic, At ENDO 2006 In Boston

QUEBEC CITY, Canada, June 27 /PRNewswire-FirstCall/ - AEterna Zentaris Inc. today announced that it presented Abstract No. P3-257 during a poster presentation entitled "ZEN-019, A Peptidomimetic from a New Class of Orally Active GnRH (LHRH) Antagonists"(x), on Monday, June 26, 2006 in the Exhibit Hall of the Boston Convention & Exhibition Center in Boston, Massachusetts, during the 2006 Annual Meeting of the Endocrine Society (ENDO 2006).

(x)Authors: Klaus W. Paulini, Silke Baasner, Matthias Gerlach, Emmanuel

Polymeropoulos, Peter Schmidt, Michael Teifel and Eckhard G. Guenther.

ZEN-019, an oral LHRH antagonist peptidomimetic, demonstrated in vivo activity by suppressing plasma testosterone levels. The Company's in vivo data showed that using ZEN-019 with a single, oral administration (20 mg/kg) in rats, lead to efficient and revocable suppression of plasma testosterone levels for up to 12 hours. Furthermore, a repeat of the dosing of ZEN-019 increased the suppression time without accumulation in the plasma.

Dr. Jurgen Engel, Executive Vice President, Global R&D and Chief Operating Officer at AEterna Zentaris commented, "We are very pleased to have had the opportunity to present our positive in vivo data on ZEN-019 at ENDO this week. ZEN 019, developed in our laboratory, is an innovative and promising candidate for further development and as an oral application, this new generation compound may prove to be very complementary to our LHRH antagonist platform."

Background on LHRH antagonists and ZEN-019

ZEN-019 is part of AEterna Zentaris' ongoing drug development program on LHRH antagonists. The Company's two lead products in this therapeutic approach are: cetrorelix, marketed for in vitro fertilization under the brand name Cetrotide(R) and in late-stage clinical development for benign prostate hyperplasia (BPH) and for endometriosis, as well as ozarelix, in Phase 2 for prostate cancer and BPH.

A major benefit of LHRH antagonists as opposed to (super) agonists is their immediate, direct action and effectiveness in dose-dependently blocking gonadotropin secretion which allows for a modulated intervention into the release of sex steroids. This avoids the necessity to reach castration levels of sex hormones under all circumstances, and leads to far less side-effects and considerably better tolerability, particularly for the non-malignant indications like endometriosis or BPH. In addition, good acceptability and better compliance, especially in long-term treatment regimes, should be the benefit of an oral application of an LHRH antagonist.

About AEterna Zentaris Inc.

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

AEterna Zentaris also owns 48.29% of the equity of Atrium Biotechnologies Inc. and 64.7% of its voting rights. Atrium is a developer, manufacturer and marketer of science-based products for the cosmetics, pharmaceutical, chemical and nutritional industries.

News releases and additional information are available at www.aeternazentaris.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.

AETERNA ZENTARIS INC. (FORMERLY/ANCIENNEMENT - LES LABORATOIRES AETERNA

CONTACT: Media Relations: Paul Burroughs, (418) 652-8525 ext. 406,paul.burroughs@aeternazentaris.com; Investor Relations: Jenene Thomas,(418) 655-6420 or (908) 996-3154, jenene.thomas@aeternazentaris.com; Torequest a free copy of this organization's annual report, please go tohttp://www.newswire.ca and click on reports@cnw.