Enzalutamide plus ADT effective in Metastatic Prostate Cancer, Finds study

Enzalutamide plus ADT has previously been shown to improve clinical outcomes in men with metastatic hormone sensitive prostate cancer. Hence, Andrew J Armstrong and colleagues conducted this study to assess if and how the pattern of metastatic spread impacts efficacy of enzalutamide plus ADT in men enrolled in ARCHES.

Men with metastatic hormone sensitive prostate cancer were randomized 1:1 to enzalutamide (160 mg/day) plus ADT or placebo plus ADT, stratified by disease volume and prior docetaxel treatment. The primary end point was radiographic progression-free survival. Secondary end points included time to prostate specific antigen progression, initiation of new antineoplastic therapy, first symptomatic skeletal event and castration resistance. Post hoc analyses were performed by pattern of metastatic spread based on study entry imaging.

The following results were observed-

a. Of the overall population with metastases identified at enrollment (n=1,146), the largest patient subgroups were those with bone metastases only (n=513) and those with bone plus lymph node metastases (n=351); there were fewer men with lymph node metastases only (n=154) and men with visceral±bone or lymph node metastases (n=128).

b. Enzalutamide plus ADT reduced the risk of radiographic progression versus placebo plus ADT in men with bone metastases only (HR 0.33) and bone plus lymph node metastases (HR 0.31).

c. Similar improvements in secondary end points were also observed in these subgroups.

Therefore, the investigators concluded that "treatment with enzalutamide plus ADT provides improvements in men with bone and/or lymph node metastases, but may be less effective in men with visceral patterns of spread."

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Armstrong AJ, Shore ND, Szmulewitz RZ, Petrylak DP, Holzbeierlein J, Villers A, Azad A, Alcaraz A, Alekseev B, Iguchi T, Gomez-Veiga F, Rosbrook B, Lee HJ, Haas GP, Stenzl A. Efficacy of Enzalutamide plus Androgen Deprivation Therapy in Metastatic Hormone-Sensitive Prostate Cancer by Pattern of Metastatic Spread: ARCHES Post Hoc Analyses. J Urol. 2020 Dec 28:101097JU0000000000001568.

doi: 10.1097/JU.0000000000001568.