Secondary hormone therapy with enzalutamide also effective for metastatic prostate cancer affecting the lung or liver

This study examined the effects of enzalutamide (Xtandi) in men with metastatic castration-resistant prostate cancer (mCRPC) that has spread to the lungs and/or liver. Researchers reported that enzalutamide is safe and effective for men with mCRPC affecting the lung or liver.

When prostate cancer spreads outside of the prostate (known as metastatic prostate cancer), tumors can form in distant parts of the body. The most common site of metastatic prostate cancer is on the bone. Metastatic prostate cancer can also affect distant organs, including lungs and liver (visceral disease). Visceral disease is often associated with poorer clinical outcomes.

Standard treatment for metastatic prostate cancer is hormone therapy. By reducing levels of male hormones active in cancer growth (such as testosterone), survival can be increased. However, cancer can continue to spread despite standard hormone therapy. This is referred to as metastatic castration-resistant prostate cancer (mCRPC).

Secondary hormonal treatments, such as enzalutamide, have shown promising results in improving survival in men with mCRPC. However, more studies are needed examining the benefit of enzalutamide in men with mCRPC who have visceral disease.

The aim of this study was to investigate enzalutamide in the treatment of mCRPC with visceral disease.

1,199 men with mCRPC were randomly assigned to receive enzalutamide or placebo (substance with no effect on the body). Of these, 278 men had visceral disease. 97 men had liver metastases, 152 had lung metastases, and 29 men had both liver and lung metastases. Treatment outcomes were followed for an average of 14.4 months.

35.1% of men with visceral liver disease showed a treatment response of 50% or more (based on blood test) with enzalutamide. 52.1% of men with visceral lung disease showed the same treatment response. Enzalutamide extended overall survival (time from treatment until death from any cause) by an average of 3.9 months for men with visceral disease.

In patients with liver metastases, enzalutamide significantly reduced the risk of disease progression (based on imaging tests) by 35% compared to placebo. 12-months overall survival rate with enzalutamide was 37.7%. This was significantly higher compared to 20.6% of men with liver metastases receiving placebo.

In patients with lung metastases, enzalutamide significantly reduced the risk of disease progression (based on imaging tests) by 61% compared to placebo. 12-months overall survival rate with enzalutamide was 65.1%. This was significantly higher compared to 55.3% with placebo.

No significant differences in enzalutamide-related side effects were observed between patients with visceral disease and those without. Fatigue was the most common side effect associated with enzalutamide in patients with visceral disease.

Researchers concluded that men with mCRPC who have visceral disease have better outcomes with enzalutamide than with placebo.