Bicalutamide or enzalutamide: which is better with ADT in men with advanced prostate cancer?

The study compared the effectiveness of bicalutamide (Casodex) to enzalutamide (Xtandi), both in combination with androgen deprivation therapy (ADT) in men with metastatic hormone-sensitive prostate cancer (mHSPC). The comparison showed that enzalutamide with ADT improves the outcomes particularly in Black men with mHSPC. 

Patients with mHSPC are usually treated with hormone therapy such as ADT. ADT reduces the production of androgens (male sex hormones such as testosterone). Reducing these androgens prevents cancer cell growth.

Both enzalutamide and bicalutamide are anti-androgen medications. Anti-androgens block testosterone from reaching the prostate cancer cells. A standard treatment for mHSPC involves ADT and bicalutamide. However, the effectiveness of enzalutamide plus ADT compared to bicalutamide plus ADT in patients with mHSPC is not known yet.

This study involved 71 men with mHSPC. 29 men were Black, 41 were White and 1 was Asian. All patients received ADT. Additionally, patients were randomly assigned to receive either enzalutamide (36) or bicalutamide (35). Response to treatment was measured through the prostate-specific antigen (PSA; a protein made by the prostate that increases in prostate cancer) level reduction. The average follow-up time was 39 months.

Overall, more men treated with enzalutamide (94%) had a PSA lower than 4ng/ml within 7 months of starting treatment compared to bicalutamide (65%). Black men had a significantly higher PSA response with enzalutamide (93%) after 7 months compared to bicalutamide (42%).

Enzalutamide was associated with a significantly longer time until PSA levels started rising again (by 85%) compared to bicalutamide. It was also associated with a 69% higher survival compared to bicalutamide. This benefit was similar for men of all races.

This study concluded that enzalutamide plus ADT showed significant improvements in the outcomes of patients with mHSPC, particularly in Black men.

This study had a very small number of participants and a short follow-up period. It was also funded by Astellas Pharma Inc., the manufacturer of enzalutamide.