Pioneering drug offers hope to prostate cancer sufferers – but not for three years

Published on Monday 21 July 2008 22:13

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".

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.

ANALYSIS: Search for 'wonder drug' faces ever-evolving disease

THE last decade has seen major leaps forward in cancer treatment in the search for the latest "wonder drug".

Developments such as the creation of drugs which target particular types of cancer have brought new hope to patients.

These include treatments such as Herceptin for breast cancer, which works when cancer cells have a large amount of a protein called HER2.

New drugs are also being developed that block hormones driving many cancers, such as prostate, testicular and breast cancer.

Scientists are also developing tests to show which patients are most likely to respond to drugs.

A test to show if a drug will aid a specific patient is likely to lead to more patients accessing treatment, as money is not wasted elsewhere. One of the most exciting developments of recent years has been the creation of the first cancer vaccine. This targets the human papilloma virus, which causes cervical cancer.

Widespread vaccination of schoolgirls is starting this year in the UK, though it will be several years before results are seen. Work is also continuing to develop vaccines to treat those already diagnosed with cancer.

The biggest challenge facing scientists, however, is the ever-evolving nature of cancer, as patients will eventually become resistant to many of the treatments being developed.

CASE STUDY: Abiraterone has given me a year of near normality

SIMON Bush was first diagnosed with aggressive prostate cancer in 2005.

Radiotherapy and hormone therapy initially reduced the severity of the cancer, but tests in August 2006 revealed it had returned with force.

Two courses of chemotherapy did not work and Mr Bush, who worked as a banker before he became ill, was referred to take part in the Royal Marsden trial of abiraterone.

After just a week, Mr Bush started to see a drop in his PSA levels – a marker for prostate cancer.

And within six weeks, the 50-year-old from London had gone from taking the maximum dose of painkillers for his bone pain to taking none at all.

"Last year I was in severe pain because of my prostate cancer, which had spread to my bones," the father of two said. "Chemotherapy and other treatments had failed and the news that I had very few treatment options available to me was devastating for my family.

"Abiraterone has allowed me to have a year so far of near normality. The changes in my life have been dramatic, from managing thousands of people in a major bank to facing a very uncertain future, then to renewed hope thanks to this drug trial."

Mr Bush said his wife, Nana, and two sons, aged 18 and 21, were "absolutely delighted" he had taken part in the abiraterone trial.

And he described the results of the drug as "amazing".

But he said he was aware there would come a time when the new drug would stop working.

"The difference is that now I know that there are so many different drugs they are working on that, when this stops there could be something else.

"I did not think that way before I started on this trial."

Mr Bush added: "Hopefully this will encourage more people with cancer to take part in trials because there is some fantastic work being carried out, and they are discovering more every day."