Aeterna Zentaris Issues Encouraging Updated Data on LHRH Receptor-Targeted Disorazol Z Cytotoxic Conjugates

Aeterna Zentaris Inc.

(the "Company") today presented encouraging updated proof-of-concept results for Disorazol Z cytotoxic conjugates, such as AEZS-125 and AEZS-138, in human ovarian and endometrial cancer xenograft models. Results further showed the compounds' high potential for the treatment of luteinizing hormone-releasing hormone ("LHRH") receptor positive tumors. Data were presented earlier today by Babette Aicher, PhD, the Company's Director of Preclinical Development, during a poster presentation at the American Association for Cancer Research ("AACR") annual meeting currently being held in Washington D.C. The study is funded through a grant from the German Ministry of Education and Research. Juergen Engel, PhD, Aeterna Zentaris President and CEO stated, "Disorazol Z cytotoxic conjugates such as AEZS-125 and AEZS-138 are an extension of our AEZS-108 innovative LHRH-targeted platform in oncology. These results confirm the encouraging data presented at the ENA Symposium in November 2012, and will enable us to better select a specific drug candidate for further preclinical development expected to start during this quarter." Conclusions * Conjugates of D-Lys^6-LHRH and Disorazol Z retained strong binding to the LHRH receptor and showed potent inhibition of tubulin polymerization. Cellular cytotoxicity of the conjugates was in the low nanomolar EC[50] range. Increased cytotoxicity in cells over-expressing the LHRH receptor, support receptor targeting as a mechanism of action; * AEZS-125 and AEZS-138 have been identified as the most promising candidates; * The LHRH receptor-dependent efficacies of Disorazol Z - D-Lys^6-LHRH conjugates in vitro and in mouse xenograft models that were presented, support the principle of tumor targeting by the LHRH receptor as already employed by the drug candidate AEZS-108, which is currently in a Phase 3 study in endometrial cancer and in Phase 2 studies in triple-negative breast cancer, bladder cancer and prostate cancer. The poster, "LHRH receptor targeting as mechanism of anti-tumor activity for cytotoxic conjugates of Disorazol Z with the LHRH receptor agonistic peptide D-Lys^6-LHRH", B. Aicher et al. can be viewed through this link.