AElig;terna Zentaris Inc . 1405 du Parc-Technologique Blvd. Qu bec (Qu bec) Canada G1P 4P5 T 418 652-8525 F 418 652-0881 www.aezsinc.com Press Release For immediate release Aeterna Zentaris Reports Fourth Quarter and Ful

terna Zentaris Inc. 1405 du Parc-Technologique Blvd.

Qu bec (Qu bec) Canada G1P 4P5 T 418 652-8525 F 418 652-0881

Aeterna Zentaris Reports Fourth Quarter and Full-Year 2011

Financial and Operating Results

amounts are in U.S. dollars (unless otherwise noted)

Quebec City, Canada, March 27, 2012 Aeterna Zentaris Inc.

(NASDAQ: AEZS) (TSX: AEZ) (the Company ), a late-stage drug development company specializing in oncology and endocrine therapy, today reported financial and operating results as at and for the fourth quarter and the year ended

Perifosine (Oral Akt Inhibitor)

AEZS-108 (LHRH-Targeted Cytotoxic Conjugate)

AEZS-130 (Oral Ghrelin Agonist)

Corporate Developments

Subsequent to Year-End

At-The-Market Issuance Program

Cash and cash equivalents and short-term investment totalled $46.9

million as at December 31, 2011, compared to $33.9 million as at December 31, 2010.

Juergen Engel, Ph.D., Aeterna Zentaris

President and Chief Executive Officer, commented, 2011 has been marked by significant strategic achievements as we continued to move our lead products through the pipeline, secured two additional partnerships for perifosine and materially

strengthened our cash position. We are now eagerly awaiting results for the Phase 3 trial of perifosine in colorectal cancer. Should results of the perifosine CRC trial prove to be conclusive, our primary focus would be to pursue NDA and MAA filings

for perifosine with U.S. and European regulatory authorities. If perifosine is found to be safe and effective, it could provide a much needed novel treatment for thousands of patients afflicted with this disease, worldwide; as well, it would

represent a large market opportunity for the Company.

Our other late-stage drug development priorities for this year are the patient

enrollment into the Phase 3 trial with perifosine in multiple myeloma which has been expanded to several countries outside the United States over the last several months; the NDA filing for AEZS-130 as the first oral diagnostic test for AGHD;

and the initiation of a registration Phase 3 trial with AEZS-108 in endometrial cancer. We also look forward to advancing earlier-stage key anticancer product candidates from our pipeline, including AEZS-112, AEZS-120 and Erk/PI3K inhibitors.

Dennis Turpin, CA, SVP and Chief Financial Officer at Aeterna Zentaris stated, With the Company s $46.9 million cash position

as at December 31, 2011, and the collaboration of our perifosine licensee partners, we are well poised to pursue our focused product pipeline development strategy.

CONSOLIDATED RESULTS AS AT AND FOR THE FOURTH QUARTER ENDED DECEMBER 31, 2011

Revenues were $12.6 million for the quarter ended December 31, 2011, compared to $10 million for the same quarter in 2010. The comparative increase in revenues is due primarily to higher

deliveries of Cetrotide to Merck Serono and to the recording of a milestone payment from Yakult with respect to

the initiation of a Phase 1/2 trial with perifosine in CRC in Japan, partly offset by the lower royalties in 2011 attributable to a contingent payment from Cowen recorded in December 2010.

R&D costs, net of refundable tax credits and grants were $7.8 million for the quarter ended December 31, 2011, compared to

$5.4 million for the same quarter in 2010. The comparative increase in R&D expenses primarily results from the increase in third-party costs incurred in connection with the advancement of perifosine, AEZS-108 and Erk/PI3K compounds

(AEZS-129, AEZS-131, AEZS-132)-related activities.

Selling, general and administrative ( SG&A ) expenses were

$5.4 million for the quarter ended December 31, 2011, compared to $3.2 million for the same quarter in 2010. The comparative increase in SG&A expenses is mainly related to the recognition of an impairment loss on property, plant

and equipment as well as an additional onerous lease provision, combined with the pre-launch and marketing efforts related to the potential commercialization of perifosine in Europe, and the increase in foreign exchange loss.

amounted to $7.5 million, or $0.07 per basic and diluted share, for the quarter ended December 31, 2011, compared to $6.6 million, or $0.08 per basic and diluted share, for the same quarter in 2010. The comparative increase in net

loss is mainly attributable to the higher R&D and SG&A expenses, partly offset by the significant increase in net finance income and by higher gross margin relating to sales of Cetrotide .

CONSOLIDATED RESULTS FOR THE FULL YEAR ENDED DECEMBER

Revenues were $36.1 million for the year ended December 31, 2011, compared to

$27.7 million for the year ended December 31, 2010. The comparative increase in revenues is due primarily to higher deliveries of Cetrotide to Merck Serono and to the recording of a milestone payment from Yakult with respect to the initiation of a Phase 1/2 trial with perifosine in CRC in Japan,

partly offset by the lower royalties in 2011 attributable to a contingent payment from Cowen recorded in December 2010.

of refundable tax credits and grants, were $24.5 million for the year ended December 31, 2011, compared to $21.3 million for the year ended December 31, 2010. The comparative increase is mainly attributable to an increase in

third-party costs incurred in connection with the advancement of perifosine, AEZS-130 and Erk/PI3K compounds (AEZS-129, AEZS-131, AEZS-132)-related activities.

Selling, general and administrative ( SG&A ) expenses were $16.2 million for the year ended December 31, 2011, compared to $12.6 million for the year ended

December 31, 2010. The comparative increase in SG&A expenses was mainly due to the recognition of impairment losses and to the initiation of pre-launch and marketing efforts related to the potential commercialization of perifosine in

Net loss for the year ended December 31, 2011 was $27.1 million, or $0.29 per basic and diluted

share, compared to $28.5 million, or $0.38 per basic and diluted share for the year ended December 31, 2010. The comparative decrease in net loss is largely due to the significant increase in license fees revenues, as well as net finance

income, partly offset by lower margin contribution from Cetrotide , higher net R&D costs and SG&A

expenses, as well as an income tax expense recorded in 2011.

Management will be hosting a conference call for the investment community beginning at 8:30 a.m. (Eastern Time) tomorrow, Wednesday, March 28, 2012, to discuss the 2011 fourth quarter and

full-year results. Individuals interested in participating in the live conference call by telephone may dial, in Canada, 514-807-9895 or 647-427-7450, outside Canada, 888-231-8191. They may also listen through the Internet at www.aezsinc.com

in the newsroom section. A replay will be available on the Company s website for 30 days following the live event.

reference, the Management s Discussion and Analysis ( MD&A ) for the fiscal year 2011 with the associated Audited Consolidated Financial Statements can be found at www.aezsinc.com.

About Aeterna Zentaris Inc.

Zentaris is a late-stage oncology drug development company currently investigating potential treatments for various cancers including colorectal, multiple myeloma, endometrial, ovarian, prostate and bladder cancer. The Company s innovative

approach of personalized medicine means tailoring treatments to a patient s specific condition and to unmet medical needs. Aeterna Zentaris deep pipeline is drawn from its proprietary discovery unit providing the Company with

constant and long-term access to state-of-the-art therapeutic options. For more information please visit www.aezsinc.com.

Forward-Looking Statements

This press release contains forward-looking statements made pursuant to the safe harbour provisions of the U.S. Securities Litigation

Reform Act of 1995. Forward-looking statements involve known and unknown risks and uncertainties that 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 risk that safety and efficacy data from any of our Phase 3 trials may not coincide with the data

analyses from previously reported Phase 1 and/or Phase 2 clinical trials, 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 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, unless required to do so by a governmental authority or by applicable law.

Ginette Beaudet Valli res

Investor Relations Coordinator

Director of Communications

(418) 652-8525 ext. 406

Consolidated Statements of

Comprehensive Loss Information

Consolidated Statement of Financial

Position Information