Post by Deanne Jenkyns on Jul 7, 2008 12:38:50 GMT 1
Gene test that can show if cancer drugs will cure you
By Jerome Burne
Last updated at 2:03 AM on 17th June 2008
For years, cancer doctors have known that many patients aren't helped by the drugs they're given. For instance, only 20 per cent of those with advanced lung cancer will benefit from certain drugs.
Even among those receiving a very effective drug such as tamoxifen for breast cancer, 30 per cent don't respond.
The trouble is that, until now, there hasn't been any reliable way of working out who will do best on which treatments. But that is about to change. An important study has found that people with a certain type of gene won't benefit from selected cancer drugs.
Researchers are running trials to test how genes affect the way people respond to different treatments
This is hugely significant because it means gene tests can be used to work out which patients will do best on a drug, and as a result cancer treatments will become much more effective.
Meanwhile, thousands of patients will be saved from the debilitating side-effects of chemotherapy they are given without gaining any benefit.
And because doctors will be able to better target expensive treatments, drugs currently not recommended by NICE because they are not cost-effective could soon be re-evaluated.
'It's not so much a new dawn, more that someone has opened the blinds and let the sun in.' That's how Dr David Sidransky, a leading cancer specialist, has described the significance of the research, which was presented at a major cancer conference in America earlier this month.
The gene involved is called K-ras - it affects the rate at which tumours divide and spread. Researchers have suspected for some time that a common, faulty form of the gene stops certain drugs working.
'The faulty gene could be carried by as many as 40per cent of people with lung and colon cancers,' explains Professor Ian Cree, a pathologist at the Translational Oncology Research Centre at Queen Alexandra Hospital in Portsmouth.
'What's new is that now we've got the evidence showing if you target treatment at people who have a "neutral" version of the gene, you get much better results.'
Recent studies have linked many other genes with poorer or better responses to chemotherapy. Leading experts now hope that the success with K-ras will stimulate proper gene testing, and the effect on treatment could be dramatic.
'We are on the edge of a whole new era of molecular diagnosis,' says Professor Karol Sikora of Imperial College School of Medicine and one of the UK's leading cancer experts.
'Eventually, cells from your cancer will be tested for a whole range of genes and biomarkers, and a computer analysis will tell you the balance of benefits and side effects of various drugs.'
In fact, doctors already do one routine gene test on the NHS. Women with breast cancer are only offered the drug Herceptin - which can cut the chances of the cancer coming back by 50 per cent - if they have the HER2 gene. If you don't have the gene, the drug won't do you any good.
'It's not so much a new dawn, more that someone
has opened the blinds and let the sun in'
Testing for the K-ras gene should soon become just as routine. Earlier this month, a European drugs advisory committee recommended that a drug called Erbitux be made the first treatment for colon cancer for those with the neutral version of the K-ras gene.
Because the UK now follows European advice, the drug will eventually be licensed for use in the UK. Other drugs that do well with the neutral K-ras gene include Iressa and Tarceva, used to treat lung and colon cancers.
Even more drugs in this group are coming down the pharmaceutical pipeline. Not only are these drugs good at tackling cancer, but they have fewer side-effects. They are also expensive - which is why gene discoveries are so important.
'The cost of these new drugs can be hard to justify, which is why NICE has refused to license some,' says Professor Cree.
'But if we can give them only to the people who benefit, and in some situations that will be half the number who are getting them now, that will bring the overall costs down and make it clear they are much better value for money.' If he can get NHS approval, the Portsmouth hospital where Professor Cree works may soon be the first in the UK to test lung cancer patients' gene type before treating them with Tarceva.
'At the moment, we have the ridiculous situation that in England, NICE has refused to licence Tarceva for lung cancer because it is not value for money, while in Scotland it's given to all such patients.
'So the patients who could benefit in England don't, while half those who do get it in Scotland don't benefit. All because no one is using the relevant genetic test.' What's needed, according to Professor Sikora, is a more organised system for developing diagnostic tests for use with cancer drugs.
'Already in America the drug regulator, the Federal Drugs Administration, has been having talks with insurance companies about developing these biomarker tests. It may not be in the interests of drug companies to develop them but they can help patients and cut costs,' he says.
Breakthrough raises hopes of tailor-made
treatment for every patient
'However a lot more research needs to be done before we can start running genetic tests on all cancer patients. Right now, the Department of Health and NICE should be having talks about the best way to start identifying and testing potential biomarkers.'
There is no shortage of candidates: many other genes have been found to affect the way drugs work, although none have been properly checked for reliability yet.
The cancer charities are now looking into gene tests. 'We are funding a number of trials to test how genes affect the way people respond to treatments such as radiotherapy,' says Henry Scowcroft of Cancer Research UK.
'Some patients respond badly and it would be helpful to predict who was going to have a problem.'
The charity is also funding a study to identify the 30per cent of breast cancer patients who don't benefit from tamoxifen. The tests doctors use at the moment, which are based on clinical symptoms such as the size of the tumour, gives them only a rough idea.
A few private patients have paid to have the K-ras test through Medical Solutions, a firm which carries out many of the HER-2 tests for NHS trusts.
It is also possible to have a test, used widely in the U.S., to help doctors decide whether a woman who has had a breast lump removed should have further chemotherapy.
However, British experts believe this needs further testing.
In the meantime, there are calls for the NHS to do more to investigate the use of genetic testing for cancer generally. Another leading expert, Professor Gordon McVie, a senior consultant at the European Institute of Oncology in Milan and founder of the UK National Cancer Research Institute, says the NHS is simply not doing enough.
'Molecular diagnostics need to be taken up much faster,' he says. 'This is what is happening in Europe where cancer centres are already delivering state-of-the-art treatments to patients who will respond to them on the basis of genetic and other tests.
'The NHS is failing in this. It needs to start using these tests fast so drugs are given in the most effective way. The big challenge now is going to be working out how to help those patients who don't benefit from existing drugs.'
By Jerome Burne
Last updated at 2:03 AM on 17th June 2008
For years, cancer doctors have known that many patients aren't helped by the drugs they're given. For instance, only 20 per cent of those with advanced lung cancer will benefit from certain drugs.
Even among those receiving a very effective drug such as tamoxifen for breast cancer, 30 per cent don't respond.
The trouble is that, until now, there hasn't been any reliable way of working out who will do best on which treatments. But that is about to change. An important study has found that people with a certain type of gene won't benefit from selected cancer drugs.
Researchers are running trials to test how genes affect the way people respond to different treatments
This is hugely significant because it means gene tests can be used to work out which patients will do best on a drug, and as a result cancer treatments will become much more effective.
Meanwhile, thousands of patients will be saved from the debilitating side-effects of chemotherapy they are given without gaining any benefit.
And because doctors will be able to better target expensive treatments, drugs currently not recommended by NICE because they are not cost-effective could soon be re-evaluated.
'It's not so much a new dawn, more that someone has opened the blinds and let the sun in.' That's how Dr David Sidransky, a leading cancer specialist, has described the significance of the research, which was presented at a major cancer conference in America earlier this month.
The gene involved is called K-ras - it affects the rate at which tumours divide and spread. Researchers have suspected for some time that a common, faulty form of the gene stops certain drugs working.
'The faulty gene could be carried by as many as 40per cent of people with lung and colon cancers,' explains Professor Ian Cree, a pathologist at the Translational Oncology Research Centre at Queen Alexandra Hospital in Portsmouth.
'What's new is that now we've got the evidence showing if you target treatment at people who have a "neutral" version of the gene, you get much better results.'
Recent studies have linked many other genes with poorer or better responses to chemotherapy. Leading experts now hope that the success with K-ras will stimulate proper gene testing, and the effect on treatment could be dramatic.
'We are on the edge of a whole new era of molecular diagnosis,' says Professor Karol Sikora of Imperial College School of Medicine and one of the UK's leading cancer experts.
'Eventually, cells from your cancer will be tested for a whole range of genes and biomarkers, and a computer analysis will tell you the balance of benefits and side effects of various drugs.'
In fact, doctors already do one routine gene test on the NHS. Women with breast cancer are only offered the drug Herceptin - which can cut the chances of the cancer coming back by 50 per cent - if they have the HER2 gene. If you don't have the gene, the drug won't do you any good.
'It's not so much a new dawn, more that someone
has opened the blinds and let the sun in'
Testing for the K-ras gene should soon become just as routine. Earlier this month, a European drugs advisory committee recommended that a drug called Erbitux be made the first treatment for colon cancer for those with the neutral version of the K-ras gene.
Because the UK now follows European advice, the drug will eventually be licensed for use in the UK. Other drugs that do well with the neutral K-ras gene include Iressa and Tarceva, used to treat lung and colon cancers.
Even more drugs in this group are coming down the pharmaceutical pipeline. Not only are these drugs good at tackling cancer, but they have fewer side-effects. They are also expensive - which is why gene discoveries are so important.
'The cost of these new drugs can be hard to justify, which is why NICE has refused to license some,' says Professor Cree.
'But if we can give them only to the people who benefit, and in some situations that will be half the number who are getting them now, that will bring the overall costs down and make it clear they are much better value for money.' If he can get NHS approval, the Portsmouth hospital where Professor Cree works may soon be the first in the UK to test lung cancer patients' gene type before treating them with Tarceva.
'At the moment, we have the ridiculous situation that in England, NICE has refused to licence Tarceva for lung cancer because it is not value for money, while in Scotland it's given to all such patients.
'So the patients who could benefit in England don't, while half those who do get it in Scotland don't benefit. All because no one is using the relevant genetic test.' What's needed, according to Professor Sikora, is a more organised system for developing diagnostic tests for use with cancer drugs.
'Already in America the drug regulator, the Federal Drugs Administration, has been having talks with insurance companies about developing these biomarker tests. It may not be in the interests of drug companies to develop them but they can help patients and cut costs,' he says.
Breakthrough raises hopes of tailor-made
treatment for every patient
'However a lot more research needs to be done before we can start running genetic tests on all cancer patients. Right now, the Department of Health and NICE should be having talks about the best way to start identifying and testing potential biomarkers.'
There is no shortage of candidates: many other genes have been found to affect the way drugs work, although none have been properly checked for reliability yet.
The cancer charities are now looking into gene tests. 'We are funding a number of trials to test how genes affect the way people respond to treatments such as radiotherapy,' says Henry Scowcroft of Cancer Research UK.
'Some patients respond badly and it would be helpful to predict who was going to have a problem.'
The charity is also funding a study to identify the 30per cent of breast cancer patients who don't benefit from tamoxifen. The tests doctors use at the moment, which are based on clinical symptoms such as the size of the tumour, gives them only a rough idea.
A few private patients have paid to have the K-ras test through Medical Solutions, a firm which carries out many of the HER-2 tests for NHS trusts.
It is also possible to have a test, used widely in the U.S., to help doctors decide whether a woman who has had a breast lump removed should have further chemotherapy.
However, British experts believe this needs further testing.
In the meantime, there are calls for the NHS to do more to investigate the use of genetic testing for cancer generally. Another leading expert, Professor Gordon McVie, a senior consultant at the European Institute of Oncology in Milan and founder of the UK National Cancer Research Institute, says the NHS is simply not doing enough.
'Molecular diagnostics need to be taken up much faster,' he says. 'This is what is happening in Europe where cancer centres are already delivering state-of-the-art treatments to patients who will respond to them on the basis of genetic and other tests.
'The NHS is failing in this. It needs to start using these tests fast so drugs are given in the most effective way. The big challenge now is going to be working out how to help those patients who don't benefit from existing drugs.'
LC charity Ball