Aeterna Zentaris Regains North American Rights for Perifosine from Keryx

Aeterna Zentaris to continue ongoing Phase 3 trial in multiple myeloma

QUEBEC CITY, May 7, 2012 /PRNewswire/ - Aeterna Zentaris Inc. (NASDAQ: AEZS) (TSX: AEZ) (the "Company") today announced that it and Keryx Biopharmaceuticals, Inc. ("Keryx") (NASDAQ: KERX) have agreed to terminate their license agreement with respect to perifosine, as a result of which Aeterna Zentaris has regained in full the North American rights to its Akt inhibitor anticancer compound, perifosine, in all indications. The Company also announced that it will continue the ongoing Phase 3 trial in multiple myeloma with this compound. Termination of the agreement was effective as of May 4, 2012.

Under the terms of the agreement to terminate, all intellectual property and development data, including orphan drug designations and Investigational New Drug ("INDs") applications on perifosine generated by Keryx, have been transferred to Aeterna Zentaris. In return, the Company has agreed to pay low single-digit royalties to Keryx on future net sales of perifosine in North America (U.S., Canada and Mexico).

Juergen Engel, PhD, Aeterna Zentaris President and CEO stated, "Our decision to continue the Phase 3 trial in multiple myeloma is based first and foremost on the existing solid preclinical and clinical data, and on the support for this drug among key opinion leaders in this field. Additionally, we believe that market opportunity, examples of other drugs enjoying success after facing setbacks, as well as the reasonable investment required to move forward with this study up to the predefined interim analysis, also make this a sound decision for the Company. Perifosine in multiple myeloma remains a key component of our deep pipeline focused on providing novel, targeted treatment options for cancer patients facing unmet medical needs."

Paul Richardson, MD, Clinical Director of the Jerome Lipper Multiple Myeloma Center at Dana-Farber Cancer Institute commented, "On behalf of my colleagues involved worldwide in the ongoing pivotal trial comparing bortezomib and dexamethasone alone to the same combination with perifosine in the treatment of relapsed, refractory multiple myeloma, I am truly delighted with Aeterna Zentaris' decision to continue this key Phase 3 study. We believe there is a strong rationale for the use of perifosine as part of combination therapy in multiple myeloma, both pre-clinically and clinically. The promise of perifosine as an effective therapeutic agent given the size, strength and maturity of the phase 2 results to date is very considerable, and clearly warrants further study."

About the Phase 3 trial in multiple myeloma

The ongoing Phase 3 trial conducted under a Special Protocol Assessment, is a randomized (1:1), double-blind trial comparing the efficacy and safety of perifosine to placebo when combined with bortezomib (Velcade®) and dexamethasone in approximately 400 patients with relapsed or relapsed/refractory multiple myeloma. The primary endpoint is progression-free survival and secondary endpoints include overall response-rate, overall survival and safety. Two interim analyses have been pre-defined for the study. Approximately 265 events (defined as disease progression or death) will trigger the un-blinding of the data.

About Perifosine

Perifosine is a novel, oral anticancer treatment that inhibits Akt activation in the phosphoinositide 3-kinase (PI3K) pathway. It has been granted orphan drug and orphan medicinal product designations from both the FDA and EMA for multiple myeloma. Perifosine has also received Fast Track designation from the FDA and positive Scientific Advice from the EMA with results from the Phase 3 trial in multiple myeloma expected to be sufficient for registration in Europe, as well as in North America. Perifosine is also being explored in combination therapy and in monotherapy in other cancer indications. Aeterna Zentaris holds rights to perifosine for North America and Europe, while rights have been licensed to Yakult Honsha for Japan, to Handok for Korea, and to Hikma Pharmaceuticals for the MENA (Middle East and North Africa) region.

About Aeterna Zentaris

Aeterna Zentaris is an oncology and endocrinology drug development company currently investigating treatments for various unmet medical needs. The Company's pipeline encompasses compounds at all stages of development, from drug discovery through to marketed products. 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.

SOURCE AETERNA ZENTARIS INC.