Washington, D.C. 20549

                            REPORT OF FOREIGN ISSUER

                      Pursuant to Rule 13a-16 or 15d-16 of
                       the Securities Exchange Act of 1934

                           For the month of April 2005

                              AETERNA ZENTARIS INC.

                        1405, boul. du Parc-Technologique
                                 Quebec, Quebec
                                 Canada, G1P 4P5

                    (Address of principal executive offices)

Indicate by check mark whether the registrant files or will file annual reports
under cover of Form 20-F or Form 40-F.

                     Form 20-F _____   Form 40-F   X


Indicate by check mark whether the registrant by furnishing the information
contained in this Form is also thereby furnishing the information to the
Commission pursuant to Rule 12g3-2(b) under the Securities Exchange Act of 1934

                            Yes _____   No  X

If "Yes" is marked, indicate below the file number assigned to the registrant in
connection with Rule 12g3-2(b): 82-_____

                                 DOCUMENTS INDEX

Documents Description

1.           Press release dated April 11, 2005 - AEterna Zentaris Announces
             Initiation of a European Multi-Center Phase II Trial of D-63153 in
             Hormone-Dependent Prostate Cancer

                                                         [AETERNA ZENTARIS LOGO]

AETERNA ZENTARIS INC. 1405 du Parc-Technologique Blvd.
Quebec (Quebec) Canada  G1P 4P5  T 418 652-8525  F 418 652-0881

                                                          PRESS RELEASE
                                                          For immediate release


QUEBEC CITY, CANADA, APRIL 11, 2005 - AEterna Zentaris Inc. (TSX: AEZ; Nasdaq:
AEZS) today announced the initiation of a European multi-center Phase II trial
to evaluate the safety and efficacy of D-63153, a fourth generation LHRH
(Luteinizing Hormone Releasing Hormone) antagonist, in patients with
hormone-dependent prostate cancer.

The Phase II trial will further assess the ability of D-63153 to suppress
testosterone levels in a dose-dependent manner and related anti-tumor activity
based on objective tumor response. This trial will be fully funded by Spectrum
Pharmaceuticals, Inc. (Nasdaq: SPPI), AEterna Zentaris' U.S. development partner
for D-63153.

In a prior Phase I trial, evaluating multiple doses of D-63153 in 18 male
volunteers, D-63153 injections were well tolerated and demonstrated an immediate
and dose-dependent suppression of testosterone plasma levels reaching castrate
levels within the first 12 hours of application. The duration of suppression was
dose-dependent, with the single injection of highest dose leading to
testosterone suppression for 27 days.

"We are very pleased with the advancement of clinical program for D-63153, and
look forward to working with Spectrum to advance the program in additional
indications", said Gilles Gagnon, President and Chief Executive Officer of
AEterna Zentaris. "We believe that LHRH antagonists such as D-63153 have several
potential advantages in treating prostate cancer, including rapid and
dose-dependent suppression of testosterone levels and avoidance of flare-up
effects associated with the use of currently marketed LHRH agonists. As such, we
are excited about the potential of D-63153 for prostate cancer patients in need
of more effective and safer therapies."


In August 2004, AEterna Zentaris granted to Spectrum Pharmaceuticals an
exclusive license to develop and market D-63153 for all potential indications in
North America (including Canada and Mexico) and India. AEterna Zentaris received
an upfront payment which included cash and equity of Spectrum, at signature, and
is eligible to receive payments upon achievement of 

certain development and regulatory milestones, in addition to royalties on
potential net sales. AEterna Zentaris retains exclusive rights to the rest of
world and will share with Spectrum upfront and milestone payments, royalties or
profits from potential sales in Japan.


According to American Cancer Society's 2004 Cancer Facts and Figures, over
230,000 new prostate cancer cases are projected in the United States in 2005.
With an estimated 30,000 deaths, prostate cancer is the second leading cause of
cancer deaths in men in the US. According to Prostate Cancer Foundation, one in
six American men will develop prostate cancer in the course of his lifetime. In
the European Union, the annual incidence of new prostate cancer cases is
estimated at198,000, according to Globocan 2002 estimates.


AEterna Zentaris Inc. is an oncology and endocrine therapy focused
biopharmaceutical company with proven expertise in drug discovery, development
and commercialization. The Company's broad 20 product pipeline leverages five
different therapeutic approaches, including LHRH antagonists and signal
transduction inhibitors. The lead LHRH antagonist compound, cetrorelix, is
currently marketed for IN VITRO fertilization under the brand name Cetrotide(R).
Cetrorelix is also in late-stage clinical development for endometriosis and
benign prostatic hyperplasia (BPH). The lead signal transduction inhibitor
compound, perifosine, is an orally-active AKT inhibitor that is in several Phase
II trials for multiple cancers.

AEterna Zentaris also owns 50.7% of Atrium Biotechnologies Inc. (TSX:, a
leading developer, manufacturer and marketer of value-added products for the
cosmetics, pharmaceutical, chemical and nutritional industries.

News releases and additional information about AEterna Zentaris are available on
its Web site


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 LOGO]



Paul Burroughs
(418) 652-8525 ext. 406

Ginette Vallieres
(418) 652-8525 ext. 265

Matthias Seeber



     Pursuant to the requirements of the Securities Exchange Act of 1934, the
registrant has duly caused this report to be signed on its behalf by the
undersigned, thereunto duly authorized.

                                 AETERNA ZENTARIS INC.

Date:  April 11, 2005            By:  /s/Mario Paradis
     -----------------              -------------------------------------------
                                      Mario Paradis
                                      Senior Finance Director and Corporate