SUO 2017: Progression-Free Survival (PSA) Endpoint

Washington, DC ( Dr. Mohler gave a talk on the usage of PSA free survival (PFS) as an intermediate endpoint for prostate cancer (PC) clinical trials. PC is a complex disease with many controversial aspects of management. There is lack of sound data to support most recommendations. Unfortunately acquisition of meaningful data is compromised by slow growth rate and competing causes of death.

Looking specifically at biochemical recurrence (BCR) after radical prostatectomy (RP), we know it happens in less than 40% of high risk disease, and there are more than 10 known definitions. In contrast, when looking at low risk disease, the number needed to treat to prevent 1 PC death is very high.

Dr. Mohler suggests PC clinical trial endpoints, which will serve as alternative to overall survival (OS). For the low risk disease he suggests the MEAL study, and for the high risk disease, he suggests the androgen annihilation study. The MEAL pilot trial hypothesis is that PC patients can make major changes in dietary pattern intervention. This is a telephone based dietary counseling program, with centralized “personal trainer” service that will end after 3 different phases spanning over 18 months.  After 12 and 24 months a prostate biopsy will be performed. The primary endpoint will be clinical progression, relying on PSA increase or progression on repeat prostate biopsy. Secondary endpoints will include incidence of active treatment, adherence to diet and quality of life questionnaires.

Dr. Mohler moved on to the high risk disease, where he described the androgen annihilation trial. This will entail recruitment of over 500 patients who have had a prior RP with BCR and no metastatic disease or prior ADT. Patients will be randomized to 3 arms: 1. LHRH antagonist, 2. LHRH antagonist +Apalutamide and 3. LHRH antagonist+ Apalutamide + Abiraterone/prednisone for a duration of 12 months. The primary objective will be PSA PFS. This study is currently open at 10 sites out of the 50 planned sites.

Dr. Mohler concluded his talk by naming several challenges faced by PC patients. These include prevention of conversion of active surveillance to treatment, treating and curing BCR, and using innovative intermediate endpoints.

Presented by: James L. Mohler, MD, Associate Director and Senior Vice President, Translational Research, Chief, Inter-Institutional Academics, Professor of Oncology, Roswell Park Cancer Institute, Professor of Urology, Jacobs School of Medicine and Biomedical Sciences, University at Buffalo, Rosewell Park Cancer Institute, Buffalo, New-York, USA

Written by: Hanan Goldberg, MD @GoldbergHanan Society of Urologic Oncology Fellow University of Toronto, Princess Margaret Cancer Centre at the 18th Annual Meeting of the Society of Urologic Oncology, November 20-December 1, 2017 – Washington, DC