In a nutshell
The authors reviewed the benefit of enzalutamide (Xtandi) in treating advanced hormone-resistant (castration-resistant) prostate cancer.
Some background
Hormone therapy is a common treatment used in prostate cancer. It targets the male sex hormones active in prostate cancer, such as testosterone. Some patients may develop resistance to hormone therapy and may no longer respond to treatment. This is known as hormone-resistant prostate cancer. Enzalutamide is a form of hormone therapy used in advanced (cancer that has spread) prostate cancer. It functions by blocking the production of male sex hormones and stopping the growth of cancer.
Further studies are required to determine the effect of enzalutamide in advanced hormone-resistant prostate cancer.
Methods & findings
The aim of this study was to review the benefit of enzalutamide in advanced hormone-resistant prostate cancer.
In a phase III trial, men treated with enzalutamide had a 37% reduced risk of death compared to patients who were given a placebo (control drug). Enzalutamide patients had an overall survival (patients who were still alive following treatment) of 18.4 months compared to 13.6 months in the placebo group. Patients on enzalutamide also experienced a 50% decrease in prostate specific antigen levels (PSA – protein elevated in the blood in the presence of prostate cancer). Time from treatment until PSA progression was 8.3 months in the enzalutamide group compared to 3 months in the placebo group.
In another study, patients who had not responded to previous hormone therapies were treated with enzalutamide for 14.9 weeks. 46% of patients experienced a PSA decline of more than 30%. 21% of patients experienced a PSA decline of more than 50%. The median (midpoint) progression-free survival (patients who did not experience cancer growth after treatment) was 12 weeks. The median overall survival was 31.6 weeks.
872 patients were treated with enzalutamide for a median follow-up of 16.6 months. 845 patients were treated with placebo. Enzalutamide–treated patients had a 21% reduced risk of death compared to placebo patients. 65% of enzalutamide–treated patients experienced progression-free survival compared to 14% of placebo patients. Enzalutamide–treated patients experienced an median overall survival of 32.4 months. Patients treated with enzalutamide experienced a 6 month increase in time from treatment until quality of life (QoL- patient’s ability to function on a physical, mental and social level) deterioration.
The most common side effects to treatment were fatigue, nausea, constipation, diarrhea, hot flashes, muscle and bone pain and high blood pressure.
The bottom line
The authors concluded that enzalutamide caused a significant delay in disease progression and QoL deterioration. They further indicated that treatment with enzalutamide showed modest improvement in overall survival in advanced hormone-resistant prostate cancer.
The fine print
Further studies are needed to determine the long-term side-effect profile of enzalutamide.
What’s next?
If you are considering enzalutamide treatment, please consult your doctor on potential risks and benefits.
Published By :
Cancer management and research
Date :
Jun 12, 2015
