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 2008

                          Commission File No. 000-30752

                              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 /X/ Form 40-F / /

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


1.   Press Release dated April 22, 2008: AEterna Zentaris' Partner,
     Spectrum, Provides Update on Ozarelix in Benign Prostatic

                                                                AETERNA ZENTARIS

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 22, 2008 - AEterna Zentaris Inc. (NASDAQ: AEZS; TSX:
AEZ), a global biopharmaceutical company focused on endocrine therapy and
oncology, today announced that its partner, Spectrum Pharmaceuticals (NASDAQ:
SPPI), released Phase 2b results for ozarelix, a luteinizing hormone-releasing
hormone (LHRH) antagonist in benign prostatic hyperplasia (BPH).

Spectrum indicated that ozarelix demonstrated sufficient clinical activity to
justify its continued development in BPH. Based on these results, Spectrum is
planning to submit a protocol to the FDA for the next study of ozarelix in BPH.

"We are pleased that Spectrum is proceeding with plans for their upcoming
study," stated Paul Blake, M.D., Senior Vice President and Chief Medical Officer
of AEterna Zentaris. "AEterna Zentaris remains committed about the potential of
LHRH antagonists for BPH, particularly for our lead candidate cetrorelix, which
has produced robust and consistent findings in Phase 2 trials and is currently
being evaluated in three multi-center Phase 3 trials in the United States,
Canada and Europe." He said that results from the cetrorelix Phase 3 program are
expected in the third quarter of 2009.


Ozarelix is an injectable fourth generation LHRH antagonist administered as an
intramuscular injection. In August 2004, AEterna Zentaris granted Spectrum
Pharmaceuticals an exclusive license to develop and market ozarelix for all
potential indications in North America (including Canada and Mexico) and India,
while AEterna Zentaris retained exclusive rights to the rest of the world. In
addition, Spectrum was granted the right to receive 50% of any upfront and
milestone payments, royalties and/or profits from sales of ozarelix in Japan.

On July 26, 2006 AEterna Zentaris licensed the Japanese rights for all ozarelix
potential oncology indications to Nippon Kayaku, a key player in the Japanese
oncology market.

                                                                AETERNA ZENTARIS


Cetrorelix pamoate is an investigational agent that has demonstrated in Phase 2
studies to provide fast and long-lasting relief of BPH symptoms while being well
tolerated, with a low incidence of sexual side effects. Cetrorelix is part of
AEterna Zentaris' LHRH antagonist therapeutic approach. This peptide-based
active substance was developed by the Company in cooperation with Nobel Prize
winner Prof. Andrew Schally, currently of the U.S. Veterans Administration in

Cetrorelix acetate is marketed under the brand name Cetrotide(R), the first LHRH
antagonist approved for therapeutic use as part of IN VITRO fertilization
programs (controlled ovarian stimulation/assisted reproductive technologies) in
Europe, the U.S. and Japan. It was launched on the market through Serono (now
Merck Serono) in the United States, Europe and in several other countries, as
well as in Japan through Shionogi.


Cetrorelix pamoate is being studied in three Phase 3 trials which will include
approximately 1,500 men with symptomatic BPH in the United States, Canada and
Europe. One Phase 3 efficacy trial, primarily in the United States and Canada
and with additional sites in Europe, involves approximately 600 patients (which
are fully enrolled) and is being led by Herbert Lepor, M.D., Professor and
Martin Spatz Chairman of Urology, New York University School of Medicine, New
York. In the trial, patients enter a 4-week run-in no-treatment observation
period to confirm severity and stability of voiding symptoms based on the
International Prostate Symptom Score (IPSS). Patients are then randomly
allocated to cetrorelix or placebo in a double-blind fashion. Patients are
administered cetrorelix by intra-muscular (IM) injection at Week 0, 2, 26 and 28
and are followed up to Week 52. Then, in an open-label extension, patients will
receive cetrorelix by IM injection at Week 52, 54, 78 and 80 will be followed up
to Week 90.

A second, similarly designed multi-center Phase 3 efficacy study, being led by
Professor Frans M.J. Debruyne, M.D., Ph.D., from the Netherlands, will enroll
approximately 400 patients in Europe. The third Phase 3 trial is an open-label,
single-armed multi-center safety study involving approximately 500 patients in
both North America and Europe, and is being led by Joel Kaufman, M.D., Associate
Clinical Professor of Urology, University of Colorado School of Medicine,
Denver, Colorado, and Urology Research Options, Aurora, Colorado.

The primary endpoint for both North American and European efficacy studies is
absolute change in IPSS between baseline and Week 52. Other efficacy endpoints
include additional measures of BPH symptom progression and the need for
BPH-related surgery. Safety endpoints include changes in sexual function. Other
important endpoints include plasma changes in levels of testosterone, and
assessment of other adverse events.

The cetrorelix Phase 3 program is based on comprehensive clinical practice
guidelines to ensure quality control, including input from expert advisors on
study design, publishing results in peer-reviewed journals and discussion of the
studies with regulatory agencies.


                                                                AETERNA ZENTARIS


Benign prostatic hyperplasia (BPH) is one of the most common diseases of aging
men - affecting more than 20 million men in the United States - but its etiology
is far from being completely understood. Data from ongoing research suggest BPH
and its associated lower urinary tract symptoms (LUTS) are more complex
conditions than once thought. While previous research on BPH etiology tended to
focus on testosterone and other hormones, more recent research suggests other
factors may play a greater role in the development of BPH and LUTS - including
inflammation, various growth factors, and adrenoreceptors.

BPH-associated LUTS include frequent urination and/or urgent need to urinate,
waking at night to urinate (nocturia), difficulty starting urination and/or weak
urinary stream, and feeling that the bladder is not completely empty after
urination. While current therapies provide some efficacy in BPH they are
associated with troublesome sexual side effects.


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

News releases and additional information are available at


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 requested by a
governmental authority or applicable law.

Dennis Turpin, CA
Senior Vice President and Chief Financial Officer
(908) 626-5517


                                                                AETERNA ZENTARIS

Paul Burroughs
Director of Communications
(418) 652-8525 ext. 406




     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 24, 2008          By: /s/Dennis Turpin
--------------------              --------------------------------------------
                                  Dennis Turpin
                                  Senior Vice President, Chief Financial Officer