Patient Information
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Patient Questions and Answers - Abiraterone
Dr Gert Attard - Clinical Research Fellow and Co-investigator at The Institute of Cancer Research (ICR) and The Royal Marsden Hospital
Could you please provide some background information on this new cancer drug called abiraterone?
Abiraterone is a drug that is taken as a tablet once a day. It was initially developed by chemists at the ICR in the 1990s. The drug works by blocking the production of male hormones, which we now know drive prostate cancer. Currently the drug is only available on clinical trial.
How effective has abiraterone been as a treatment in the early trials?
More than 1000 patients worldwide have been treated with abiraterone on Phase I, II and III studies.
We have recently published a research paper presenting the results of the first clinical study in 54 patients who had all tried most of the standard hormone treatments available before they started abiraterone.
In this study we have observed, in up to two thirds of patients, a decline in PSA levels, symptom improvement (including a significant reduction in pain) and tumour shrinkage on scans.
Is the drug a cure?
No. The drug works in most patients for about 18 months and then the cancer comes back. There are, however, a few patients who have been on abiraterone for three years and their cancer remains controlled. So for each patient the benefit is different. About half of prostate cancer patients have an abnormality in a gene called ERG and the majority of patients who did very well on abiraterone had this ERG gene abnormality. Clinicians involved in the trial can test for these ERG genes to identify the patients most likely to benefit from abiraterone.
What are the side-effects of this drug?
Abiraterone has very few side-effects. As it is a hormone treatment, its side-effects include loss of libido, tiredness and breast enlargement. Also, abiraterone can cause fluid retention or hypertension but this has been easily controlled in patients.
Can I ask my oncologist to prescribe abiraterone to treat my prostate cancer?
No. Currently abiraterone is only available on clinical trial as more research is needed to ensure its safety and confirm its benefit. Currently all places on the clinical trial in the UK have been filled or allocated. There may be future clinical trials involving this drug.
If any of these take place in the UK, they may be listed on http://www.cancerhelp.org.uk
The international site: www.clinicaltrials.gov may also contain information about trials taking place in the US and around the world. These trials will have very specific eligibility criteria which patients will need to meet. These websites will provide information about this and list the hospitals involved. Patient referrals will not be accepted for consideration until the trial opens.
What is the difference between Phase I, II and III drug studies?
A Phase I study is designed to test the safety of an experimental drug on a small group of patients (between 20 and 80 people). It evaluates the safety of the drug, determines a safe dosage range and identifies any side-effects. Phase II trials are designed to test how effective the drug is in a larger group of patients. Phase III evaluates the extent to which this drug extends the life of the patient, establishes how effective it is compared to other commonly used treatments and monitors the side-effects in a larger group of patients.
In which stage of the trial process is abiraterone?
We have completed Phase II studies, with both patients who have had chemotherapy and those who have not. We have now moved into testing this drug in a Phase III study on 1180 patients at 150 hospitals across the world. All the spaces on this trial have already been filled. We expect these results to be available next year.
The Phase III trial that has now finished recruiting is a “two to one randomisation”, where two thirds of patients receive abiraterone in combination with prednisone (a steroid) and one third receive a placebo plus prednisone.
Neither the patient nor the consulting doctor knows which arm of the trial the patient is on; patients are managed exactly the same. For both arms of the trial, patients remain on the trial for as long as the treatment they are receiving is benefiting them. We appreciate that it is frustrating for both physicians and patients that some patients on the trial do not receive the drug. This Phase III trial is designed to clearly show whether abiraterone extends life and unfortunately that means a third of patients are taking a placebo.
Is abiraterone likely to become a standard treatment for patients with advanced prostate cancer?
We certainly hope so, however until the results from the Phase III trial have been completed, we are not in a position to commit either way. Clearly from the level of activity that we have seen in the Phase I/II study, we hope that this drug will be able to help as many patients as possible in the future.
Does abiraterone have the potential to become a standard treatment for patients in the earlier stages of the disease?
The current Phase III study involves patients who have already received chemotherapy. Although this trial has finished recruiting people, there are other studies planned, hopefully starting towards the end of 2009, which will test the drug in patients who are in an earlier stages of the disease and who haven’t had chemotherapy. We also hope to treat men who haven’t yet shown any symptoms, with the aim of studying whether abiraterone will delay the onset of any symptoms.
How long before abiraterone will be available for general use?
It is really too soon to say. Scientists at the ICR first need to analyse the Phase III clinical trial results. Abiraterone needs to continue to show a significant benefit to patients while having minimal side-effects. There are also regulatory approvals required which our scientists aren’t involved in. That all takes time. We hope if everything goes well, it may be available for general use as early as 2011.
Is abiraterone being tested as a treatment for other cancer types?
Cancer Research UK are currently recruiting breast cancer patients to be involved in a phase I/II trial for this drug abiraterone taking place in the UK only. There is a strict eligibility criteria. For more information please visit: CancerHelp UK or call the Cancer Research UK team of specialist nurses on 0808 800 40 40..Lines are open Monday to Friday, between 9am and 5pm.
BREAST CANCER
Breast Cancer - Phase I and II Trials involving the drug abiraterone (United Kingdom only)
Phase I and II breast cancer clinical trials involving the drug abiraterone are open for recruitment.
Women who meet the selection criteria are being invited to seek a referral to these trials. These trials are open to UK residents only and will be taking place at The Royal Marsden Hospital in partnership with The Institute of Cancer Research.
Patients will require a referral from their oncologist complete with their full medical history.
For more information about the trial please click here or call Cancer Help UK on 0808 800 40 40.
Abiraterone is a new drug which has been discovered and developed at The Institute of Cancer Research and is licensed to Cougar Biotechnology.
It has been tested in Phase I and II trials for the treatment of advanced and aggressive prostate cancer. Those trials have shown up to 80 per cent of prostate cancer patients have experienced an improvement of their condition while being treated with the drug. Over time some patients have developed a resistance to the drug.
The Phase I and II breast cancer trials will be the first clinical trials utilising abiraterone in the treatment of breast cancer. For more information about what researchers are investigating in Phase I and II trials, visit Cancer Research UK here.
