Results of a systematic review including two large trials have confirmed that adding a drug called abiraterone to standard long-term hormone therapy helps men with prostate cancer that has spread to live longer. These results, from the STOPCaP study, were published this week in the European Journal of Cancer.
Abiraterone is a type of hormone therapy currently licensed to treat prostate cancer that has spread and has stopped responding to standard hormone therapy. Both trials tested using it earlier, in men starting long-term standard hormone therapy for the first time.
Overall, the results showed that adding abiraterone to standard hormone therapy reduced the risk of death by 38%. This means that after three years, 69 out of 100 men who received abiraterone were alive compared to 55 out of 100 men who just had standard hormone therapy.
Abiraterone also reduces the risk of prostate cancer getting worse by 55%. This means that after three years, 58 out of 100 men who received abiraterone were alive without the disease having worsened, compared to 30 out of 100 men who just had standard hormone therapy.
There was no evidence that the effect of abiraterone varied according to how well men were when they joined the trial, or whether the disease had spread to their nodes. There was a suggestion that the size of the benefit might differ by age.
The analysis found that adding abiraterone to standard long-term hormone therapy did increase heart, liver and circulation side-effects, but there was no increase in deaths related to this treatment.
This study is the first systematic review looking at adding abiraterone to standard long-term hormone therapy. The results are based on 2201 men with prostate cancer that has spread beyond the prostate taking part in the STAMPEDE and LATITUDE trials. This accounts for 82% of men randomised to abiraterone plus hormone therapy versus hormone therapy alone. The results provide reliable evidence confirming that adding abiraterone to long-term hormone therapy is a highly effective treatment option for men with prostate cancer that has spread beyond the prostate.
Further research is needed to compare the effect of adding abiraterone to hormone therapy against adding docetaxel to hormone therapy (which previous research has shown is also effective), or whether they can be combined to have even greater benefit.