British researchers believe a new drug could treat up to 80 per cent of patients with an aggressive and previously drug-resistant form of prostate cancer. A phase I clinical trial by the Institute of Cancer Research and the Royal Marsden Hospital found that the drug abiraterone caused tumours to shrink and levels of prostate specific antigen (PSA) - a protein associated with prostate cancer activity - to drop in the majority of the 21 patients who received the drug.
The results suggest the drug could benefit up to 10,000 British men each year who are diagnosed with aggressive prostate cancer. Dr Sally Burtles, director of drug development for Cancer Research UK, said: "We are delighted that this drug, originally developed by us, is continuing to show promise and has the potential to make a real difference to men with an aggressive form of prostate cancer." The drug works by blocking the production of key hormones involved in driving prostate cancer growth, both in the testes and in the tumour itself. This is particularly important in aggressive forms of prostate cancer, in which the tumour tissue is believed to produce its own supply of hormones for tumour growth and therefore cannot be treated with existing drugs that only block hormone production by the testes. According to lead researcher Dr Johann de Bono, "The Royal Marsden patients in this study have been monitored for up to two-and-a-half years and with continued use of abiraterone they were able to control their disease with few side-effects." The researcher also noted that some patients were able to stop taking morphine for the relief of bone pain. "These men have very aggressive prostate cancer which is exceptionally difficult to treat and almost always proves to be fatal," he continued. "We hope that abiraterone will eventually offer them real hope of an effective way of managing their condition and prolonging their lives."
The results of the phase I clinical trial, which involved 21 men with prostate cancer that had already proven resistant to several hormone therapies, are published in the Journal of Clinical Oncology. Cancer Research UK's prostate cancer expert, Professor Malcolm Mason, who is based at Cardiff University School of Medicine, said: "These early results are extremely exciting but there's a lot more work needed to establish what abiraterone's place will be in treating men with prostate cancer. "At the moment the studies are being done on a small number of men with very advanced disease so it's much too early to say what role the drug might have in treating others with earlier stage prostate cancer. We need the results of a much larger study to see if this early promise will be fulfilled."