Patients with metastatic castration-resistant prostate cancer who have progressed after chemotherapy live significantly longer if treated with the drug Abiraterone ( Zytiga )compared to placebo.
Patients who received Abiraterone had a median survival of four months longer than patients receiving a placebo.
Men with metastatic castration-resistant prostate cancer have a poor prognosis, with only about one in three alive five years after diagnosis.
Because the growth of prostate cancer is fuelled by the male hormone testosterone, reduction of the testosterone level in the body, for example through hormone therapy, can slow the tumor growth. But most prostate cancers eventually become resistant to these treatments and resume growing.
Abiraterone is designed to treat these tumors by inhibiting the production of androgen in the testes, the adrenal glands and prostate cancer tumors themselves.
The Phase-III trial included 1195 patients whose metastatic, castration-resistant prostate cancer had previously been treated with one of two chemotherapeutic agents that included Docetaxel.
Among the 398 patients randomly assigned to receive the corticosteroid Prednisone plus placebo, median overall survival was 10.9 months. Among the 797 who received Abiraterone plus Prednisone, median survival was 14.8 months.
Significant differences also emerged between the placebo and treatment groups for all of the trials secondary endpoints, including time to prostate-specific antigen ( PSA ) progression, radiographic progression-free survival and PSA response rate.
The benefits of Abiraterone were determined during a pre-specified interim analysis of the study, prompting the trials Independent Data Monitoring Committee to recommend unblinding the trial, and allowing anyone on the placebo arm to be offered Abiraterone.
. The researcher noted that there were still some unanswered questions about Abiraterone.
The results of the study have shown that the drug adds to the range of treatment options available for patients with advanced disease, with limited toxicity.
Source: ESMO Meeting, 2010
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