FORM 6-K
                       SECURITIES AND EXCHANGE COMMISSION
                             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 May 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 May 31, 2005 - AEterna Zentaris' Partner Spectrum 
     Granted IND from FDA to Conduct Phase I/II Clinical Trial with 
     D-63153 in Hormone-Dependent Prostate Cancer in the United States


                                                       [AETERNA ZENTARIS LOGO]


AEterna Zentaris Inc. 1405 du Parc-Technologique Blvd.
Quebec (Quebec) Canada G1P 4P5 T 418 652-8525 F 418 652-0881
www.aeternazentaris.com

                                                          Press Release
                                                          For immediate release

AEterna Zentaris' Partner Spectrum Granted IND from FDA to Conduct Phase I/II 
Clinical Trial with D-63153 in Hormone-Dependent Prostate Cancer in the 
United States

Quebec City, Canada, May 31, 2005 - AEterna Zentaris Inc. (TSX: AEZ; NASDAQ: 
AEZS) announced that the U.S. Food and Drug Administration (FDA) has approved 
a recently submitted Investigational New Drug Application (IND) by its North 
American partner, Spectrum Pharmaceuticals (NASDAQ: SPPI), for D-63153, a 
fourth generation LHRH (Luteinizing Hormone Releasing Hormone) antagonist 
administered as a depot formulation. Spectrum is now in a position to conduct 
a Phase I/II trial with D-63153 in hormone-dependent prostate cancer and, 
thereby, expand the clinical development of D-63153 to the United States.

"We are very encouraged by the continued progress of D-63153, including this 
near-term expansion of clinical development to the U.S., as well as the 
recently initiated European Phase II trials with this product in 
hormone-dependent prostate cancer and benign prostate hyperplasia," said 
Gilles Gagnon, President and Chief Executive Officer of AEterna Zentaris. 
"D-63153 is an important element of our strategic development and we are 
pleased with the strong commitment by our new North American partner, 
Spectrum, to work towards the full development of this innovative LHRH 
antagonist compound."

ABOUT D-63153 STRATEGIC ALLIANCE WITH SPECTRUM PHARMACEUTICALS

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 the world 
and will share with Spectrum upfront and milestone payments, royalties or 
profits from potential sales in Japan.


ABOUT PROSTATE CANCER

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 U.S. According to Prostate Cancer Foundation, 
one in six American men will develop prostate cancer in the course of his 
lifetime.

ABOUT AETERNA ZENTARIS INC.

AEterna Zentaris Inc. is an oncology and endocrine therapy focused 
biopharmaceutical company with proven expertise in drug discovery, 
development and marketing. The Company's broad 20 product pipeline leverages 
six 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 a novel, first-in-class, oral 
anticancer agent that modulates several key signal transduction pathways, 
including AKT, MAPK, and JNK that have been shown to be critical for the 
survival of cancer cells. Perifosine has demonstrated single agent anti-tumor 
activity in Phase I and Phase II studies and is currently being studied as a 
single agent and in combination with several forms of anti-cancer treatments 
for various forms of cancer, including non-small cell lung cancer and breast 
cancer.

AEterna Zentaris also owns 50.3% of Atrium Biotechnologies Inc. (TSX: 
ATB.sv), 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 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.


                                     - 30 -

CONTACTS

MEDIA RELATIONS
Paul Burroughs
(418) 652-8525 ext. 406
paul.burroughs@aeternazentaris.com

INVESTOR RELATIONS
Ginette Valli[caad 234]eres
(418) 652-8525 ext. 265
ginette.vallieres@aeternazentaris.com

EUROPE
Matthias Seeber
+49 69 42602 3425
matthias.seeber@aeternazentaris.com


                                   SIGNATURE

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: May 31, 2005          By: /s/ Mario Paradis
                                -----------------------------------------------
                                Mario Paradis, CA
                                Senior Finance Director and Corporate Secretary