GU Cancers 2021 | ARCHES: enzalutamide plus ADT in mHSPC subgroups

As the audience may know, the ARCHES trial led to the FDA approval of enzalutamide in men with metastatic hormone-sensitive prostate cancer in December of 2019. The ARCHES study was a global randomized Phase III trial of enzalutamide with ADT as compared to ADT and placebo in men who have metastatic hormone-sensitive prostate cancer.

The basis of the approval was based on substantial delays and radiographic progression-free survival, delays in castration resistance, time to next therapies, time to skeletal events and maintained quality of life with no unexpected toxicities. The overall survival data is still immature and will be likely updated in the coming year or two.

This poster was intended to look at an important subgroup of patients as defined by how patients present with metastatic disease. One group of men commonly has local therapy and then develops metastatic disease. We call that the M0 population at diagnosis. And then one group of men commonly presents with de novo metastatic disease, where metastatic disease is diagnosed right at the beginning.

And the purpose of this poster is to analyze the efficacy of enzalutamide in these subgroups. And not surprisingly, we found that enzalutamide provided substantial benefits on all endpoints, including the primary endpoints and all secondary endpoints, regardless of whether a patient presented with metastatic disease or whether they had relapsed metastatic disease after local therapy. These patient groups did differ substantially in their baseline characteristics. The patients who presented to de novo commonly had more high-grade disease, had a worse functional status, had a different pattern of spread, and a worse prognosis. But they still had a substantially improved outcome with the use of enzalutamide. We did see some slight differences in toxicity where the M0 patients may have experienced a little bit more fatigue, but overall no unexpected adverse events. And you can look at this poster for some of the details.