For advanced prostate cancer, androgen deprivation therapy (ADT) has been the cornerstone of systemic therapy. The most common treatment is testosterone suppression and bicalutamide, a nonsteroidal androgen receptor antagonist.
Enzalutamide is a second-generation androgen receptor inhibitor that inhibits nuclear translocation and DNA binding in prostate cancer cells, resulting in increased cytotoxicity. This study, published in JAMA Network Open, examines the efficacy of enzalutamide and bicalutamide in combination with ADT in males with metastatic hormone-sensitive prostate cancer (mHSPC), with a focus on Black patients.
In this multicenter, open-label, 1:1 randomized trial, patients were divided into two groups based on their race (Black or other) and the severity of their bone pain (present or absent). Men with mHSPC who did not have a history of seizures and had adequate marrow, renal, and liver function were eligible for the study.
In addition to ADT, participants were randomly assigned to receive either oral enzalutamide (160 mg daily) or bicalutamide (50 mg daily). Luteinizing hormone-releasing hormone (LHRH) analog treatment was used in both groups. The primary endpoint was the seven-month prostate-specific antigen (PSA) response (SMPR) rate.
A total of 71 men were enrolled, of which 29 (41%) were Black, 41 (58%) were white, and 1 (1%) was Asian. Of these patients, 36 were randomly assigned to receive enzalutamide, and 35 were assigned to bicalutamide.
Ultimately, it was found that SMPR was achieved in 94% of patients on enzalutamide and 65% of patients taking bicalutamide. Furthermore, the 12-month PSA response rate was 84% with enzalutamide vs. 34% with bicalutamide. For non-Black patients, the SMPR was 94% among those taking enzalutamide and 86% among those taking bicalutamide, while for Black patients, the SMPR was 93% among those taking enzalutamide and 42% among those taking bicalutamide.
The researchers concluded that enzalutamide had better outcomes than bicalutamide in terms of the rate and duration of PSA response. Moreover, Black men with mHSPC had a significantly better response rate to ADT and enzalutamide vs. ADT and bicalutamide. This study is important because it supports the favorable tolerability and risk-benefit profile of ADT and enzalutamide in men with mHSPC in general and Black men with mHSPC in particular [1].
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