Aeterna Zentaris Inc. presented Phase 2 positive efficacy and safety data for its compound, AEZS-108, in advanced endometrial cancer. The trial was conducted by the German AGO Study Group and centres in Bulgaria. The presentation was made by Prof. Gunter Emons, Chairman, Department of Obstetrics & Gynaecology Georg-August University Gottingen, Germany during a poster session at the 22nd EORTC-NCI-AACR Symposium on Molecular Targets and Cancer Therapeutics currently being held in Berlin, Germany.

“The safety and efficacy of AEZS-108 in our study on advanced endometrial cancer was very encouraging,” commented Prof. Gunter Emons. “We must keep in mind that we used AEZS-108 as a single agent treatment only, and still achieved good rates of objective response and disease stabilization. Importantly from the patients’ point of view, overall survival was similar to what has been reported with more aggressive and less well tolerated combination chemotherapy regimens.”

Juergen Engel, Ph.D., president and CEO of Aeterna Zentaris added, “We would first like to thank Dr. Emons and all those involved in this trial for their dedicated work. These exciting positive results in endometrial cancer along with positive data for ovarian cancer disclosed earlier this year, reaffirm AEZS-108’s potential as a novel targeted approach for the treatment of cancer. We now look forward to the further late-stage development of AEZS-108 for the benefit of women battling gynaecological cancers.”

The poster (abstract #378) entitled, “Phase II study of AEZS-108, a targeted cytotoxic LHRH analogue, in patients with LHRH receptor positive endometrial cancer”, G. Emons, J. Sehouli, G. Gorchev, A. Hristamian, A. Staehle, LC. Hanker, P. Wimberger, M.W. Beckmann, V. Taskova, and C. Gruendker for the AGO Study Group, Germany, details the use of AEZS-108, the Company’s targeted cytotoxic drug in which doxorubicin, a well known chemotherapeutic agent, is linked to [D-Lys(6)]-luteinizing hormone releasing hormone (LHRH), in women with histologically confirmed LHRH-R positive advanced (FIGO III or IV) or recurrent endometrial cancer. Patients received a recommended dose of 267 mg/m2 by intravenous infusion over 2 hours, with re-treatment every 3 weeks, for up to 6 courses. Response rate per Response Evaluation Criteria in Solid Tumours (RECIST) was defined as primary endpoint. Secondary endpoints were safety, Time-To-Progression (TTP) and Overall Survival (OS).

In all, 44 patients entered the study. Of these, 1 patient was withdrawn prior to start of treatment and 2 patients entered as replacement for patients withdrawn for reasons other than progressive disease. Of 43 patients treated with AEZS-108, 39 were evaluable for efficacy. Responses confirmed by independent review included 2 patients with complete response (CR; 5.1%), 10 patients with partial response (PR; 25.6%), and 17 patients with stable disease (SD; 43.6%). Based on those data, an Overall Response Rate (ORR = CR+PR) of 30.8 % and a Clinical Benefit Rate (CBR = CR+PR+SD) of 74.4% can be estimated. Responses were also achieved in patients with prior chemotherapy, 1 CR, 1 PR and 2 SDs in 8 of the patients pre-treated with platinum/taxane regimens. Median time to progression (TTP) and overall survival (OS) were 7 months (30 weeks) and 14.3 months (62 weeks), respectively.

Overall, tolerability of AEZS-108 was good and commonly allowed re-treatment as scheduled. Only one patient (2%) had a dose reduction, and 17 (8%) courses were given with a delay, including also 11 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 1 case only, a patient who had been treated only 3 weeks after a surgery. Good tolerability of AEZS-108 was also reflected by a low rate of severe possibly drug-related non-hematological adverse events and which included single cases (2.4%) each of nausea, diarrhoea, fatigue, general health deterioration (Grade 4), creatinine elevation, and blood potassium decrease. No cardiac toxicity was reported.

AEZS-108 at a dosage of 267 mg/m2 every 3 weeks was active and well tolerated in patients with endometrial cancer. Hematological toxicity was rapidly reversible, and non-hematological toxicities were usually not severe, causing few deviations from scheduled treatment. The objective response rate of 31% compares well with those of single agent platinum or taxane treatment; responders included patients pre-treated with platinum/taxane combination. In addition, the rate of stable disease was 44%, resulting in a Clinical Benefit Rate of 74%. The overall survival after single agent AEZS-108 is similar to that reported for modern triple combination chemotherapy, but was achieved with lower toxicity.

This year, the American Cancer Society estimates that more than 43,000 cases of endometrial cancer - tumours in the lining of the uterus and the glands of the endometrium - will be diagnosed in the United States. Symptoms can include unexplained vaginal bleeding, painful urination, painful intercourse and soreness in the pelvic area. There is no routine test to identify endometrial cancer. Treatment options include surgery, radiation therapy, hormone therapy and chemotherapy; however, there are new treatments in development that work by targeting and destroying cancerous cells.

AEZS-108 represents a new targeting concept in oncology using a hybrid molecule composed of a synthetic peptide carrier and a well-known chemotherapy agent, doxorubicin. The product is in Phase 2 studies for the treatment of endometrial and ovarian cancer, and is also being studied for the treatment of other cancers. AEZS-108 is the first intravenous drug in a clinical study that directs the chemotherapy agent specifically to LHRH-receptor expressing tumours, resulting in more targeted treatment with less damage to healthy tissue. AEZS-108 has been granted orphan-drug designation by the FDA and orphan medicinal product designation from the EMA for the treatment of ovarian cancer. Aeterna Zentaris owns the worldwide rights to AEZS-108.

Aeterna Zentaris is a late-stage oncology drug development company currently investigating potential treatments for various cancers including colorectal, ovarian and endometrial cancer as well as multiple myeloma.