New prostate cancer drug discovered by ICR approved by FDA

18 May 2011

A drug for treating metastatic prostate cancer discovered at The Institute of Cancer Research (ICR) has been approved by the US FDA.

The new drug, abiraterone acetate, has been approved for use in combination with prednisone for the treatment of “castration-resistant” prostate cancer in patients who have received prior docetaxel chemotherapy.

“Today’s announcement marks the culmination of two decades of work at the ICR to design and develop this drug,” ICR Chief Executive Professor Alan Ashworth says. “This very significant achievement underlines the importance of drug discovery work in the not-for-profit sector.”

Abiraterone acetate was invented by Professor Mike Jarman and his colleagues in what is now the Cancer Research UK Cancer Therapeutics Unit at the ICR in Sutton, south of London. Prostate cancer cells need the male hormone testosterone to grow, so the team set out to design a drug that would cut off the source of testosterone.

The ICR continued research on abiraterone acetate with the Royal Marsden Hospital after the drug was licensed to Ortho Biotech Oncology Research & Development, Unit of Cougar Biotechnology, Inc. in 2004. ICR scientists worked with them on the pivotal trial that led to the US approval. Cougar’s affiliate, Janssen Pharmaceutical Companies, has a pending application for a license to sell the drug in Europe.

Abiraterone blocks the CYP17 enzyme complex that is involved in the synthesis of testosterone. Standard hormone treatments only block production of male hormones in the testes and not the adrenal glands, but recent research has shown that tumours can produce their own supply.

In addition, the adrenal gland continues to make male hormones. By inhibiting the pathways involved in the production of testosterone, abiraterone blocks its generation in all tissues, including in the cancer itself. This means the drug has potential to treat patients with the castration-resistant aggressive form of the disease.

Prostate cancer is the most common male cancer in the UK, with more than 35,000 new cases diagnosed annually. Around 10,000 men die of the disease every year, almost all of them from its castration-resistant form.

Professor Johann de Bono from the ICR and The Royal Marsden Hospital, who led the drug through Phase I, II and III clinical trials, says: “Prostate cancer kills one man each hour in the UK. New therapies are desperately needed. Abiraterone acetate has been approved for men who are no longer responding to other drugs and so we are very pleased that this decision means they will have another treatment available to them.”