Everolimus and bicalutamide effective in castration-resistant prostate cancer, but with side effects

This study examined the effectiveness of everolimus and bicalutamide in patients with castration-resistant prostate cancer.  The authors concluded that the combination of these two therapies was effective, but with significant side effects.

Prostate cancer can be dependent on male hormones (such as testosterone) for growth. Therapies that block these hormones are often effective (hormone deprivation therapy). However, some men become resistant to hormone deprivation. This is known as castration-resistant prostate cancer (CRPC). Treatment options are limited for men with CRPC. Hormone blocking therapies such as bicalutamide (Casodex) are used but do not have a high long-term success rate.

Everolimus (Afinitor) is a treatment that blocks the activity of a protein often found in cancer cells. Blocking this protein can decrease cancer cell growth. Blocking this protein can also cause unwanted increases in male hormone levels. It is possible that combining everolimus with bicalutamide could block the increase in hormone levels.

This study examined the effectiveness of the combination of everolimus and bicalutamide in CRPC.

24 patients with CRPC who had already received treatment were selected for this study. Each patient received a combination of bicalutamide and everolimus for cycles of 4 weeks. Patients were monitored for side effects and a decrease in levels of a protein in the blood associated with prostate cancer.

75% of the patients showed a significant decrease in protein levels. 62.5% of patients showed a more than 50% decrease in protein levels. Average overall survival time (time from treatment until death from any cause) was 28 months.

58.3% of patients suffered from severe side effects. Most effects were due to the toxic nature of everolimus. These side effects included sores in the mouth, low white blood cell levels, and low red blood cell levels. Less severe side effects also included fatigue and increased levels of fats (such as cholesterol) in the blood.

This study concluded that this combination of treatments was effective in men with CRPC, but with significant side effects. The authors suggested that further studies should explore decreasing the dosage of everolimus. 

This study was conducted on a small group. Further studies should include larger groups of patients. 

Discuss your treatment options with your physician.