Abiraterone Has Potential to Extend Prostate Cancer Survival
An experimental drug has shown promise in extending the live in prostate cancer patients who have resistant metastatic disease. Abiraterone was shown to extend lives of prostate cancer patients by almost 4 months, according to clinical trial data presented this week at the European Society for Medical Oncology.
Dr. Johann de Bono MD PhD of the Institute of Cancer Research at Royal Marsden Hospital in London and colleagues enrolled 1,195 men whose advanced cancer had proved refractory to hormonal therapy and chemotherapy. The phase III trial was conducted in 147 centers in 13 countries.
Combination of Abiraterone and Steroids Extended Survival over Placebo
Patients given a combination of 1,000 mg of abiraterone and steroids (prednisone/prednisolone 5 mg twice daily) achieved a median of 14.8 months survival compared to 10.9 months for those on steroids plus a placebo – a 36% increase. In addition, says de Bono, the time to disease progression was extended from 6.6 months for the control (placebo) group to 10.2 months in the experimental group.
Abiraterone acetate is a selective androgen biosynthesis inhibitor that acts by blocking CYP17, a gene associated with prostate cancer, and blunts the synthesis of androgen which is associated with tumor growth. Adverse effects of abiraterone were few and included fluid retention and hypokalemia (low blood potassium).
"That 3.9 months may not seem much, but you have to understand that in the history of prostate cancer, only four drugs have previously ever shown a survival benefit. Abiraterone has the potential to meet a significant unmet need so this news will be incredibly important to prostate cancer patients and their families," said Dr. de Bono.
Dr. Fortunato Ciardiello, a professor at Second University in Italy who moderated the press briefings at the ESMO conference, said that the patients in the study “represent the sickest of the sick” and that abiraterone has the potential to give as many as one of three of the patients an option which they currently do not have.
Johnson & Johnson said that it plans to file marketing applications for abiraterone in the US and Europe by the end of the year. Future clinical trials will include men at an earlier stage of disease.
The National Cancer Institute estimates that 217,730 men in the U.S. will be diagnosed with prostate cancer this year and about 32,000 will die. The disease is the second-leading cause of cancer death in American men, after lung cancer, according to the American Cancer Society.
De Bono j et al, "Abiraterone acetate plus low dose prednisone improves overall survival in patients with metastatic castration-resistant prostate cancer who have progressed after docetaxel-based chemotherapy: Results of COU-AA-301, a randomized double-blind placebo-controlled phase III study" ESMO 2010; P. 135