Aeterna Zentaris: Final Data for Phase 1 Portion of Ongoing Phase 1/2 Trial with Zoptarelin Doxorubicin in Prostate Cancer Published in Clinical Cancer Research

Aeterna Zentaris Inc.

(the "Company") today announced that an article on final data for the Phase 1 portion of the ongoing Phase 1/2 trial in prostate cancer with zoptarelin doxorubicin (formerly AEZS-108), a hybrid molecule composed of a synthetic peptide carrier and a well-known chemotherapy agent, doxorubicin, has been published in the December issue of Clinical Cancer Research. The article outlines data previously disclosed in June 2013 at the American Society of Clinical Oncology's ("ASCO") Annual Meeting, which demonstrated the compound's safety profile and promising anti-tumor activity in heavily pre‑treated men with castration- and taxane-resistant prostate cancer. These results led to the current investigator-driven Phase 2 portion in this same indication under the supervision of lead investigator, Jacek Pinski, MD, PhD, of the USC Norris Comprehensive Cancer Center. Titled, "Phase I, Dose-Escalation Study of the Targeted Cytotoxic LHRH Analog AEZS-108 in Patients with Castration- and Taxane-Resistant Prostate Cancer", Liu SV, Tsao-Wei DD, Xiong S, Groshen S, Dorff TB, Quinn DI, Tai YC, Engel J, Hawes D, Schally AV, Pinski J., the article is available at this link: Clin Cancer Res. David Dodd, Chairman and CEO of Aeterna Zentaris stated, "The Phase 1 portion data are very encouraging and we look forward to further results from the current Phase 2 portion of this investigator‑driven trial. Because luteinizing hormone-releasing hormone receptors are expressed in a great number of prostate cancers, we believe that zoptarelin doxorubicin, which specifically targets those receptors, may represent a novel targeted treatment for men with this disease. Expansion into prostate cancer with zoptarelin doxorubicin after positive Phase 2 results in endometrial and ovarian cancer, is further demonstration of the potential of this innovative compound in a variety of cancer indications which affect men as well as women, and could provide the Company with a significant market opportunity." Phase 1 Results and Conclusions Luteinizing hormone-releasing hormone ("LHRH") receptors are expressed on the cell membrane of many tumors, including prostate cancer ("PC"). This Phase I study with zoptarelin doxorubicin which targets these LHRH receptors, determined the maximum tolerated dose ("MTD") of this agent in men with taxane- and castration-resistant PC while providing additional information on its safety profile and efficacy. Zoptarelin doxorubicin was administered as an intravenous infusion every 21 days until progression or unacceptable toxicity in cohorts of 3 or 6 patients until the maximum tolerated dose ("MTD") was reached. The MTD of zoptarelin doxorubicin in this cohort was 210 mg/m2, which was lower than that seen in a Phase I study conducted in women with endometrial or ovarian cancers. The dose limiting toxicity was persistent neutropenia. Three patients had a prostate-specific antigen ("PSA") response with an additional 10 patients maintaining PSA stable disease. Of the 10 patients evaluable by RECIST criteria, 9 achieved stable disease. These findings show that zoptarelin doxorubicin has an acceptable safety profile and a signal of efficacy, lowering PSA in heavily pretreated patients with prostate cancer, and that internalization of zoptarelin doxorubicin in PC circulating tumor cells may be a viable pharmacodynamic marker. Current Phase 2 Portion of the Study This is a single-arm Simon Optimum design Phase 2 study of zoptarelin doxorubicin involving up to 37 patients with pre‑treated castration-and taxane-resistant prostate cancer, using the dose selected (210 mg/m2) in the Phase 1 portion. The primary endpoint is to evaluate the clinical benefit of zoptarelin doxorubicin for these patients. Clinical benefit will be defined as non-progression at 12 weeks with no dose‑limiting toxicity or other toxicity requiring termination of treatment. More information on the current Phase 2 portion of the trial is available at this link: NCT01240629.