Is abiraterone acetate also suitable for older men with castration resistant prostate cancer?

This study examined abiraterone acetate (Zytiga) as a treatment option for older men with metastatic castration-resistant prostate cancer.

Researchers concluded that abiraterone acetate improves overall survival in younger as well as older men with metastatic castration resistant prostate cancer.

Treatment for advanced metastatic (cancer that has spread to distant organs) prostate cancer often involves hormone therapy. Hormone therapy blocks the male hormones, such as testosterone, the cancer needs for growth. Some men become resistant to hormone therapy. This is known as metastatic castration resistant prostate cancer (mCRPC). Abiraterone acetate is often recommended as an alternative hormone therapy in men with mCRPC. Because mCRPC is more common with increasing age, the safety and effectiveness of abiraterone acetate needs to be determined in older men.

This study included 1,196 men with mCRPC. Of these, 331 men were aged 75 years or older. Patients were randomly assigned to treatment with abiraterone acetate plus prednisone (group 1, a steroid drug that reduces inflammation and pain) or with prednisone alone (group 2).

Overall survival (time from treatment until death from any cause) was significantly improved in group 1, regardless of age. Average survival among older men in group 1 was approximately 7 months longer (average 15.6 months) compared to group 2 (average 9.3 months). Survival was also improved in younger men (under age 75) in group 1 (average 15.9 months) compared to group 2 (average 12 months). Disease progression was significantly slowed in group 1 compared to group 2 in both older and younger men.

62% of older men and 60% of younger men in group 1 experienced significant side effects.  The most common effects reported included fatigue, back pain, high blood pressure, low potassium levels, and water retention. Most side effects occurred in both age groups. Less than 3% of men requested a lower dose of abiraterone acetate due to side effects.

Researchers concluded that abiraterone acetate is a safe and effective treatment option for metastatic castration-resistant prostate cancer, even in older men.