STREAM trial: Enzalutamide and androgen deprivation therapy with salvage radiation in men with high-risk PSA recurrent PC

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Published: 15 Feb 2019
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Prof Andrew Armstrong - Duke Cancer Institute, Durham, USA

Prof Andrew Armstrong speaks to ecancer at the 2019 ASCO Genitourinary Cancers Symposium about the STREAM trial investigating the use of enzalutamide and androgen deprivation therapy (ADT) with salvage radiation in patients with high-risk PSA recurrent prostate cancer.

He explains that the trial studied nearly 40 men over a course of 6 months with enzalutamide and ADT with salvage radiation showing that 65% of men were free of disease and off therapy after 3 years.

Prof Armstrong states that the 2/3 year outcomes are superior to what would normally be expected suggesting that enzalutamide could be more effective in improving long term remission rates in these patients.

Enzalutamide is established in the castration resistant setting – it improved survival in the AFFIRM study post-docetaxel; it improved survival in the PREVAIL study pre-chemotherapy; it delayed metastasis or death in non-metastatic castration resistant disease. Our STREAM study actually is a phase II study moving enzalutamide even earlier to the non-metastatic hormone sensitive setting. So this is an attempt to move enzalutamide into a setting where men are getting salvage radiation with curative intent. These are patients who have had prostatectomy, their PSAs are going up and the standard of care for them has been just radiation to the prostate bed. Many of these men will still suffer further relapses because of microscopic metastatic disease and we know that AR inhibition can be radiosensitising, that’s the basis for the better outcomes with radiation and hormone therapy over radiation alone.

We presented today the STREAM trial which is a phase II multicentre study. Nearly 40 men treated over six months with enzalutamide, ADT, salvage radiation; very well tolerated. We showed that 65% of men are free of disease and off therapy three years later. So it’s very exciting data; the two and three year outcomes are superior to what we would expect with historic data suggesting that enzalutamide actually might be more effective to improve the remission rate and long-term remission rate for these patients. It would justify larger phase III controlled studies with much longer follow-up but this serves as one of the first studies to report enzalutamide with radiation.