Androgen deprivation therapy (ADT) is often used as adjuvant treatment with radiation therapy (RT) for intermediate-risk prostate cancer (PCa). ADT is associated with multiple side effects including weight gain, loss of libido and hot flashes. In contrast, anti-androgen monotherapy has been generally better tolerated.
Assess the effectiveness of enzalutamide (an anti-androgen) monotherapy with RT for the treatment of prostate cancer in intermediate risk prostate..
This trial was an open label phase II study of 6 months of enzalutamide monotherapy with external beam radiation therapy (EBRT) for intermediate risk prostate cancer. Enzalutamide was initiated 2 months prior to EBRT The primary endpoint was PSA response measured at the end of enzalutamide administration at the six month time point. Secondary end-points include assessment of toxicity, changes in anthropomorphic body measurement, sexual function and metabolic changes.
The sample size was calculated to be 64 patients. The null hypothesis was that if ≥ 60% of the patients did not achieve a PSA nadir ≤0.2 ng/ml, the study would be deemed negative.
The results met the pre-specified end point for efficacy in that PSA values ≤0.2 were observed in 49 of 64 (77%) patients, and 60 of 64 (94%) patients had PSA values of at least <0.5ng/ml. The most frequent adverse events were hypertension and gynecomastia. There were no changes in anthropomorphic body measurements and only modest erectile dysfunction..
Using PSA response as an end-point, enzalutamide monotherapymay be as effective as ADT in combination with EBRT for patients with intermediate risk prostate cancer. It is associated with fewer side effects. Randomized trials comparing enzalutamide to ADT are justified.

Copyright © 2021. Published by Elsevier Inc.

Author