July 22, 2008
Pioneering Drug Offers Hope to Prostate Cancer Sufferers – but Not for Three Years
By Lyndsay Moss
THOUSANDS of men with prostate cancer could be helped by an "exciting" new drug which potentially represents the biggest step forward in treating the disease for 60 years, researchers revealed yesterday.The drug, abiraterone, could help prolong the lives of up to 10,000 men in the UK each year who suffer the most aggressive - and almost always fatal - form of the disease.
The news came after a study found the drug led to tumours shrinking in up to 80 per cent of patients treated. It is hoped the treatment could be widely available to patients by 2011 after full clinical trials. In the meantime, only those taking part in studies will have access to the drug.
Cancer charities and experts yesterday welcomed the research, but warned that more work was needed to prove the benefits of abiraterone.
Researchers from the Institute of Cancer Research and the Royal Marsden Hospital in London tested the drug on 21 men with advanced prostate cancer which had stopped responding to treatment.
The researchers, writing in the Journal of Clinical Oncology, found that abiraterone led to tumours shrinking in between 70 and 80 per cent of patients.
They also saw "dramatic" falls in levels of prostate-specific antigens - which indicate the severity of prostate cancer. Similar results have been observed in second-phase trials involving about 250 men, details of which have yet to be published.
Dr Johann de Bono, the lead researcher on the study, said: "Patients in this study have been monitored for up to two-and-a- half years and, with continued use of abiraterone, were able to control their disease with few side effects. A number of patients were able to stop taking morphine for bone pain.
"These men have very aggressive prostate cancer, which is exceptionally difficult to treat and almost always fatal.
"We hope abiraterone will eventually offer them real hope of an effective way of managing their condition and prolonging their lives."
The drug works by blocking the generation of key hormones which drive the growth of prostate cancers. In the most aggressive forms of prostate cancer, it is thought tumour tissue produces its own supply of these hormones. Such cases cannot be treated solely with current drugs which only block production of male hormones in the testicles.
Abiraterone blocks hormone production in all types of tissue, making it useful in treating patients with so-called "castration- resistant" prostate cancer.
It is thought the drug works equally well in men both before and after chemotherapy.
Some 10,000 men die from prostate cancer each year in the UK - almost all from the resistant forms of the disease.
Abiraterone is now the subject of a larger international study involving 1,200 men. It is also being tested on women with breast cancer in a trial funded by Cancer Research UK.
Dr Gerhardt Attard, one of the scientists involved in the latest study, said: "We're very excited about this. It is changing our understanding of prostate cancer in a way that has not been done for 50 or 60 years."
Professor David Webb, professor of clinical pharmacology at Edinburgh University, said the new drug looked "promising".
But he added: "It will be crucial to look at the balance of its benefits and harms before drawing firm conclusions."
John Neate, chief executive of the Prostate Cancer Charity described the results of the trial as "an exciting development which has been eagerly anticipated".
MORE INFO www.prostate-cancer.org.uk
WHY SO LONG? SAFETY IS KEY TO TESTING PROCESS
WITH so many new drugs being discovered by scientists, patients are often left wondering why it takes so long for them to become widely available.
Researchers are quick to point out that safety is key to bringing a new treatment to market, meaning larger studies are needed to check for any possible side-effects.
Drugs usually go through three phases of clinical trials before pharmaceutical companies apply for a licence to make them more widely available. This is to prove their safety and effectiveness in ever-larger groups of patients.
Small trials alone may not be enough to show up side-effects that emerge during much larger studies.
Professor David Webb, professor of clinical pharmacology at Edinburgh University, said: "Patients want access to these new drugs quickly, but we need to make sure they are not exposed to unnecessary damage in the process."
Only once safety and efficacy are proved can a licence be awarded.
1 Lab tests reveal that a molecule may be effective in treatment of cancer, leading to further investigation, including tests on animals 2 Phase two trials involving a small group of cancer patients, to check whether a drug is safe and has any effect 3 Phase two trials involving a larger group of patients - perhaps 100 or more - to confirm earlier results and make further checks for safety 4 Phase three trials involving 1,000 or even several thousand patients, usually as part of an international study, to confirm widespread effectiveness before a licence is applied for 5 Licence for general use of a drug in the UK is awarded by either the European Medicines Evaluation Agency or the Medicines and Healthcare Products Regulatory Agency 6 Once licensed, doctors are able to prescribe the drug to patients outside of clinical trials. However, a drug does not become available until it is approved by one of the NHS drug evaluation bodies
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