As enzalutamide has been shown to improve survival in the setting of metastatic castration-resistant prostate cancer, the biologic rationale existed that it may exceed the efficacy of ADT in conjunction with XRT.
Key features of the study are detailed below. No preliminary results have been reported yet.
This is an open label, randomized, phase III trial. It is taking place in Australia, New Zealand, USA, UK, Ireland and Europe. All participants receive LHRH antagonist for 24 months, and RT starting about week 16 delivered as 78Gy in 39 fractions, or 46Gy in 23 fractions plus brachytherapy (nodal RT optional for N0, mandatory for N1). The randomization entails either Enzalutamide 160mg daily for 24 months versus conventional non-steroidal antiandrogen for 6 months.
Expected accrual is 800 participants with a minimum follow-up of 5.5 years, which would enable 80% power to detect 33% reduction in the hazard of death assuming 5-year survival rate of 76% amongst controls. Approximate event number is 200.
Once enrolled, men undergo baseline assessments then every 8 weeks until year 2, then 3-4 monthly until year 5, 6-monthly until year 7, then annually. Assessments include: imaging with CT/MRI and bone scan at baseline, PSA progression, then 6 monthly until re-initiation of ADT, when PCWG2 criteria for CRPC are met and then 3 monthly until evidence of metastases.
Primary endpoint is overall survival, but secondary endpoints include CSS, PSA progression free survival (PFS), clinical PFS, time to subsequent hormonal therapy, time to castration-resistant disease (PCWG2 criteria), metastasis free survival (MFS), adverse events and health-related quality of life (HRQOL).
At this time, 714 participants have been recruited from 61 sites (07 February 2018).
Presented by: Scott Williams, MD
Co-Authors: Ian D. Davis, Christopher Sweeney, Martin R. Stockler, Andrew James Martin, Wendy Hague, Xanthi Coskinas, Sonia Yip, Emily Tu, Nicola Jane Lawrence, Namrata Nayar, Ray McDermott, Paul Kelly, Olwyn Deignan, Simon Hughes, Valerie Fonteyne, Bertrand F. Tombal, Paul L. Nguyen
Author Affiliation(s): Peter MacCallum Cancer Centre, Melbourne, Australia; Monash University Eastern Health Clinical School, Victoria, Australia; Dana-Farber Cancer Institute, Boston, MA; NHMRC Clinical Trials Centre, University of Sydney, Sydney, Australia; Cancer Trials Ireland, Dublin, Ireland; Guy's and St Thomas' Hospital NHS Foundation Trust, London, United Kingdom; European Organisation for Research and Treatment of Cancer, Brussels, Belgium
Written by: Thenappan Chandrasekar, MD, Clinical Fellow, University of Toronto | @tchandra_uromd at the 2018 American Society of Clinical Oncology Genitourinary (ASCO GU) Cancers Symposium, February 8-10, 2018 - San Francisco, CA