Aeterna Zentaris presents positive data from AEZS-108 Phase 2 study in ovarian cancer at ASCO 2010

Encouraging trend observed in overall survival

Aeterna Zentaris Inc. (TSX: AEZ; Nasdaq: AEZS), (the "Company"), a late-stage drug development company specialized in oncology and endocrine therapy, today announced that it presented positive efficacy and safety data for its doxorubicin targeted conjugate compound, AEZS-108, in ovarian cancer. The presentation was made by Prof. Günter Emons, Chairman, Department of Obstetrics & Gynaecology Georg-August University Göttingen, Germany, during last Saturday's poster session at the American Society of Clinical Oncology (ASCO) Annual Meeting, being held through June 8, 2010 at McCormick Place in Chicago. AEZS-108 is currently in a Phase 2 trial conducted in Europe by the German AGO Study Group (Study AGO-GYN5), in advanced ovarian and endometrial cancer, with final results expected by year-end.

The poster (abstract #5035) entitled, "Phase 2 study of AEZS-108, a targeted cytotoxic LHRH analog, in patients with LHRH receptor positive platinum resistant ovarian cancer", G. Emons, S. Tomov, P. Harter, J. Sehouli, P. Wimberger, A. Staehle, L. C. Hanker, F. Hilpert, P. Dall, and C. Gruendker, for the AGO Study Group, details the use of AEZS-108, a targeted cytotoxic drug in which doxorubicin is linked to (D-Lys(6))-luteinizing hormone-releasing hormone (LHRH), in women with histologically confirmed taxane-pretreated platinum-resistant/refractory LHRH-R positive advanced (FIGO III or IV) or recurrent ovarian cancer. Patients received a recommended dose of 267 mg/m2 by intravenous infusion over 2 hours, with retreatment every 3 weeks, for up to 6 courses. Response rate (RECIST and/or GCIG criteria) was defined as primary endpoint. Secondary endpoints were safety, time-to-progression (TTP) and overall survival (OS).

Results

42 patients with platinum-resistant ovarian cancer entered the study. Efficacy included partial response in 5 patients (11.9%) and stable disease for more than 12 weeks in 11 patients (26.2%). Based on those data, a Clinical Benefit Rate (CBR) of 38% can be estimated. Median time to progression (TTP) and overall survival (OS) were 3.5 months (104 days) and 15.6 months (475 days), respectively.

In all, tolerability of AEZS-108 was good and commonly allowed retreatment as scheduled. Only one patient (2.4%) had a dose reduction, and overall, 25 of 170 (14.7%) courses were given with a delay, including also cases in which delay was not related to toxicity. Severe (Grade 3 or 4) toxicity was mainly restricted to rapidly reversible hematologic toxicity (leukopenia / neutropenia) associated with fever in 3 cases. Good tolerability of AEZS-108 was also reflected with only a few patients with non-hematological toxicities of grade 3 (none with grade 4), including single cases (2.4%) each of nausea, constipation, poor general condition, and an enzyme elevation. No cardiac toxicity was reported.

"The efficacy of AEZS-108 in our study was encouraging, considering that it only included patients resistant to prior platinum- and taxane-based therapies", commented Prof. Günter Emons. "In these patients, a clinical benefit rate of 38% and particularly a median overall survival of over 15 months compare favourably with results for drugs such as topotecan and pegylated liposomal doxorubicin that are currently used in this setting. Furthermore, the safety profile of AEZS-108 was relatively benign with no unexpected findings and in particular, no cardiac toxicity."

Juergen Engel, Ph.D., President and CEO of Aeterna Zentaris added, "With these favourable results in refractory ovarian cancer patients, we are now looking forward to the data of our endometrial cancer study scheduled for the fourth quarter."

Conclusion - AEZS-108 was active and well tolerated in patients with heavily pre-treated platinum and taxane resistant ovarian cancer; - The safety profile confirmed the dose of 267 mg/m2; - Hematological toxicity was rapidly reversible; - Non-hematological toxicities were usually limited to lower severity; - Tolerability and CBR compare favourably with topotecan and liposomal doxorubicin; - Overall survival is encouraging as all patients treated with AEZS-108 were platinum-resistant.