Evaluating the long-term effectiveness and safety of enzalutamide plus androgen deprivation therapy in patients with metastatic hormone-sensitive prostate cancer.

This study reported the long-term effectiveness and safety of enzalutamide (Xtandi) in combination with androgen deprivation therapy (ADT) for the treatment of patients with metastatic hormone-sensitive prostate cancer (mHSPC). The data showed that enzalutamide in combination with ADT improved the overall survival over the long term with manageable side effects in these patients.

Patients with mHSPC have prostate cancer that has spread beyond the prostate gland. Generally, these patients are treated with hormone therapy such as androgen deprivation therapy (ADT). ADT reduces the production of androgens (male sex hormones such as testosterone). Reducing these androgens prevents cancer cell growth.

Enzalutamide is an anti-androgen medication. It blocks testosterone from reaching PC cells. It is used for the treatment of mHSPC. Enzalutamide plus ADT has been shown to improve clinical outcomes like overall survival and lower the risk of disease progression in men with mHSPC. However, the long-term effectiveness and safety of enzalutamide plus ADT in patients with mHSPC are still unknown.

This study involved 1125 patients with mHSPC. Patients were randomly assigned into two groups. Group 1 included 563 patients who received enzalutamide plus ADT. Group 2 included 562 patients who received standard nonsteroidal antiandrogen therapy plus ADT.  The average follow-up time was 68 months.

After 5 years, 67% of the patients in group 1 were alive versus 57% of the patients in group 2. Patients in group 1 were 30% more likely to have a better overall survival than patients in group 2. The average overall survival was not reached in either group (exceeded the average follow-up period).

After 5 years, 56% of patients in group 1 were alive without cancer progression compared to 28% of patients in group 2. 

The most common side effects were low white blood cell counts with fever (6% in group 1 vs 6% in group 2), tiredness (6% in group 1 vs 1% in group 2), and high blood pressure (10% in group 1 vs 6% in group 2). 13% of the patients in group 1 experienced memory impairment versus 4% in group 2.

This study concluded that enzalutamide in combination with ADT significantly improved overall survival over the long term, with manageable side effects in patients with mHSPC.

This study was funded by Astellas Pharma, the manufacturer of enzalutamide.