Prostate cancer is responsible for hundreds of thousands of deaths each year, so the news today that in a clinical trial of more than 1,000 men a new drug named abiraterone acetate prolonged the lives of patients with advanced prostate cancer in a by an average of four months has been greeted with considerable excitement.
Prostate cancer is currently treated by surgery, radiation, ultrasound, and hormonal therapy which blocks the secretion of testosterone and other androgens (hormones that control the development and maintenance of male characteristics) by the testes. Unfortunately in most cases after a remission of two to three years most patients on hormonal therapy progress to terminal cancer, a progression that is believed to be due at least in part to the production of androgens by tissues outside of the testes. Abiraterone acetate works by blocking the enzyme cytochrome p45017alpha that is involved in the production of androgens, including those produced by tissues outside the testes.
Abiraterone acetate was initially developed by Cancer Research UK-funded scientists working at the Institute of Cancer research, who screened a series of potential cytochrome p45017alpha blockers in mice, before selecting abiraterone acetate (then known as CB7630) due to its ability to suppress circulating testosterone to undetectable levels and markedly decreased the weights of androgen-sensitive organs without affecting organs that are not sensitive to androgens (1).
New trials are now planned to determine if abiraterone acetate can help men with less advanced prostate cancer, if it can then it may be able to offer prostate cancer patients extra years, rather than months, of life.
1) Barrie S.E. et al. “Pharmacology of novel steroidal inhibitors of cytochrome P450(17) alpha (17 alpha-hydroxylase/C17-20 lyase).” J Steroid Biochem Mol Biol. Volume50(5-6), Pages 267-273 (1994) PubMed:7918112.
Barrie SE, Potter GA, Goddard PM, Haynes BP, Dowsett M, & Jarman M (1994). Pharmacology of novel steroidal inhibitors of cytochrome P450(17) alpha (17 alpha-hydroxylase/C17-20 lyase). The Journal of steroid biochemistry and molecular biology, 50 (5-6), 267-73 PMID: 7918112