The following article features coverage from the American Society of Clinical Oncology (ASCO) 2019 meeting.

Addition of enzalutamide to standard of care for the treatment for metastatic hormone-sensitive prostate cancer (mHSPC) is associated with improved overall survival, according to study findings presented at the 2019 American Society of Clinical Oncology (ASCO) annual meeting in Chicago.

After a median follow-up of 34 months, an interim analysis of the phase 3 ENZAMET trial showed that enzalutamide plus standard of care (testosterone suppression with or without docetaxel) is associated with a significant 34% decreased risk of death compared with the use of 3 other standard nonsteroidal anti-androgen (NSAA) agents (flutamide, bicalutamide, or nilutamide) plus standard of care, Christopher J. Sweeney, MBBS, of the Dana-Farber Cancer Institute in Boston, and colleagues reported.

Dr Sweeney’s team randomly assigned 1125 men with mHSPC to receive either enzalutamide or another NSAA, in addition to standard of care. Of these men, 503 men received early doses of docetaxel and 602 did not.  The 3-year overall survival (OS) rate was 80% in the enzalutamide group compared with 72% in the NSAA group. In addition, at 3 years, 64% of the enzalutamide arm remained on study treatment compared 36% of recipients of other NSAAs.

“Physicians and patients with prostate cancer now have a new treatment option with enzalutamide, and this is especially relevant for men who cannot tolerate chemotherapy and have a lower burden of disease seen on scans,” Dr Sweeney said in an ASCO press release.

The decreased risk of death associated with enzalutamide treatment was more pronounced in men with low-volume disease and in those without planned docetaxel treatment. Among patients with low-volume disease, the enzalutamide group had a significant 52% decreased risk of death compared with patients taking other NSAAs, with 3-year OS rates of 90% vs 82%. Among patients with high-volume disease, the enzalutamide group had a 26% decreased risk of death, with 3-year OS rates of 71% vs 63%.

In the patients with no planned early docetaxel therapy, enzalutamide-treated men had a significant 49% decreased risk of death compared with those taking another NSAA, with 3-year OS rates of 83% vs 70%. Among those with planned early docetaxel therapy, the enzalutamide recipients had only a 9% decreased risk of death, with 3-year OS rates of 73% vs 74%.

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Reference

Sweeney C, Martin AJ, Zielinski RR, et al. Overall survival (OS) results of a phase III randomized trial of standard-of-care therapy with or without enzalutamide for metastatic hormone-sensitive prostate cancer (mHSPC): ENZAMET (ANZUP 1304), an ANZUP-led international cooperative group trial. Presented at the 2019 American Society of Clinical Oncology annual meeting in Chicago, May 31 to June 4. Abstract LBA2.