The results of the longer-term analysis of overall survival of the Australian-led clinical trial ENZAMET have shown that the addition of hormone therapy with a medicine called enzalutamide to standard therapy (suppression of testosterone, with or without docetaxel chemotherapy) led to sustained improvement in overall survival for people with metastatic hormone-sensitive prostate cancer.
In June 2019, the Australian and New Zealand Urogenital and Prostate Cancer Trials Group (ANZUP) presented the interim results from the ENZAMET study in the Plenary Session at the American Society of Clinical Oncology (ASCO) Annual Meeting. This showed that enzalutamide reduced the risk of dying by about one third, with 80% of people receiving enzalutamide were still alive after 3 years, compared to 72% of people receiving standard best practice treatment.
This planned longer-term analysis of the ENZAMET study was presented at the ASCO Annual Meeting in June 2022 and were published today in The Lancet Oncology. This results revealed that the benefit of adding enzalutamide was maintained, even after people on the trial had been followed up for more than 5 years on average. 67% of people receiving enzalutamide were still alive after 5 years, compared to 57% of people receiving standard best practice treatment.
The longer-term analysis also showed that the benefit of adding enzalutamide was evident in all patient subgroups, regardless of when the cancer was found to have spread, or how much was present, or whether people also received docetaxel chemotherapy. These high level findings indicate that the addition of enzalutamide should be considered as a treatment option for any patient able to receive it. The exploratory findings indicate it might not be necessary to add other treatments like chemotherapy.
Study Co-Chair, Board Chair of ANZUP and Professor of Medicine and Head of the Eastern Health Clinical School, Monash University and Eastern Health Melbourne, Professor Ian Davis, said, “ENZAMET is a unique collaboration of clinicians and scientists from Australia, New Zealand, Ireland, UK, Canada, and the USA, all coming together to work with the community to find better ways of treating prostate cancer. ENZAMET won the 2020 Trial of the Year Award, as well as awards for community involvement, and for high quality statistical conduct. Now we have very mature results confirming that the benefit of enzalutamide treatment persists even after much longer follow-up, and that a benefit is evident for various patient subgroups. We know that ENZAMET will continue to provide other important information to help us improve outcomes for people affected by prostate cancer.”
“Although ENZAMET was not primarily designed to assess the impact of testosterone suppression plus enzalutamide plus docetaxel (ie potent hormonal-chemotherapy) over testosterone suppression plus enzalutamide (potent hormonal therapy without chemotherapy), the data would suggest that the addition of concurrent docetaxel to potent hormonal therapy may only benefit people who are fit for docetaxel and have the poorest prognosis disease (ie presentation of a higher volume of metastatic disease as first diagnosis of prostate cancer). For all other patients, such as those not fit for docetaxel or not likely to benefit from docetaxel, potent hormonal therapy with testosterone suppression plus enzalutamide is one of the life prolonging treatment plans we should be discussing with all of our patients who are starting hormonal therapy for metastatic disease,” said Study Co-Chair and Director SAiGENCI – South Australian immunoGENomics Cancer Institute Professor Christopher Sweeney.
Furthermore, Professor Sweeney, noted, “ENZAMET had the flexibility to allow physicians and patients to decide whether concurrent docetaxel was an appropriate option for each unique patient and this has helped provide insights as to which patients benefit from which combination therapy. This was only possible because of the patients’ and research teams’ commitment to the clinical research process”.
The side effects of addition of enzalutamide to standard of care were overall similar to what has been experienced with enzalutamide in previous clinical trials.
Source: ANZUP
