Medicine that is tailor-made to suit individuals’ specific genetic make-up is at the cutting edge of medical research in Europe and the US.
It offers hope to people with genetic variations that make them suffer horrible side-effects from the medicines sold at their corner pharmacies.
But it comes with a huge price tag’ and in a country like ours where most people can’t even get the basic medicines, it seems like a sci-fi dream.
Despite the apparent impossibility of what is called ‘personalised medicine’, medical experts warn that scientists from developing countries need to start genetic profiling to see how the genes of their citizens impact on the diseases they experience. If they don’t, the gulf between the rich and poor might widen even further.
Dr Jens Brummer, head of laboratory medicine at the University of Hamburg, is excited about the possibilities of personalised medicine.
‘Genetic testing offers the possibility of earlier diagnosis of diseases, better treatment selection based on the right drugs and thus a better prognosis,’ says Brummer.
‘Personalised medicine replaces the one-size-fits all medicine with the right treatment for the right person at the right time.’
His university recently set up a private disease prevention clinic that caters mostly for top executives, running an extensive battery of tests on them.
While medical aids are not yet that happy to pay for genetic testing, even in Europe and the US, Brummer believes it is only a matter of time before they realise how such tests will save them a lot of money.
At the heart of personalised medicine is the recognition that individuals react differently to medication based on their genes and that the prescription of medication should be tailored to the individual.
The US has dedicated $277-million to supporting personalised healthcare this year alone, and US Health Secretary Mike Leavitt has made developing a health system to support personalised medicine one of his priorities over the next two years.
‘In the future, we’ll understand diseases at a new level,” Leavitt said in a recent address. ‘We’ll know them as gene- or molecular-based diseases. And that will give us new kinds of treatments that will be effective for both the very specific condition and the individual patient.’
High hopes for the success of personalised medicine flow directly from the sequencing of the human genome, which gave scientists new insights into how humans’ genes function.
This spurred on the rapid developments in ‘pharmacogenomics’ ‘ a field that combines genetics and pharmaceutical knowledge to unravel how genes influence the efficacy of different medicines.
One of the most important recent scientific breakthroughs in this field centres on a family of genes (called P450) in the liver. These play a vital role in processing close to a quarter of all existing medicines, including anti-depressants and anti-psychotic drugs.
Scientists have been able to classify people into three broad groups, based on genetic variations in their P450 genes. Some metabolise the medicines so fast that they are unlikely to get much benefit from them. Others process the medicines so slowly that they suffer toxic side effects, while the third ‘extensive’ group is most likely to benefit the most from the medication.
Pharmaceutical giant Roche has produced a genetic test called Amplichip P450 that is based on the P450 research. The test is able to categorise patients into the three groups and thus identify who will benefit most from different drug treatments.
While the Ampliclip test is costly ‘ around $500 a time ‘ it is able to save patients from bad side-effects and cut down on prescribing medication that simply doesn’t work.
Predictably, the focus of the pharmaceutical companies has been on diseases that most affect wealthy nations’ aging middle class populations.
So far, some of the most important progress has been made in cancer treatment. Most cancers grow when there are mutations in two groups of genes, oncogenes and tumour-suppressing genes.
This means that the targets for drug treatment are already well defined and thus present an attractive research target for the pharmaceutical industry.
Again Roche has been working on two tests, one for leukaemia and the other that is able to detect mutations of the tumour-suppressing P53 gene ‘ ‘the most frequently mutated gene in human cancers’, according to Dr Daniel O’Day, head of Roche Diagnostics.
While neither the AmpliClip leukaemia or the AmpliClip P53 have been commercially released, both offer ‘improved disease management and the possibility of early detection of cancer’, O’Day told a recent Roche diagnostics conference held in St Petersburg in Russia.
Like anti-psychotic drugs, cancer treatment has often been a bit of hit and miss, with considerable side effects for patients.
Up to half of all patients with ovarian and oesophageal cancer do not respond to treatment, while women with breast cancer can be on treatment with some drugs for two to three years before doctors realise that it isn’t working, said O’Day.
But developing tests that identify people’s genetic predisposition to diseases is not that helpful unless it is coupled with treatment.
A range of pharmaceutical companies have been at work and there are already over 20 approved drugs on the market that target specific genes.
One of these is the breast cancer medicine Herceptin (trastuzumab), the expensive breat cancer drug that a group of South African women got access to after a court battle with medical aid giant Discovery.
About a quarter of women with breast cancer have genetic variations of the gene HER2 that causes tumours to grow fast. Herceptin works to repair this and breast cancer patients with this genetic mutation respond very well to Herceptin treatment.
Access to life-saving medical treatment such as Herceptin is a human rights issue, but few developing countries are grappling with ‘personalised medicine’.
The Dean of Harvard’s School of Public Health, Professor Barry Bloom and Dang Duc Trach , the director of Vietnam’s National Programme on Immunisation, warned in a recent article in the British Medical Journal against the use of genomics simply for the development of ‘boutique medicine’ for the rich.
‘Our hope is that knowledge of the genome will encourage some medical researchers to seek new interventions that are population based and that emphasis will be put on developing inexpensive drugs (comparable to aspirin and beta blockers) and vaccines that prevent disease and disability in populations, rather than individual-based designer therapies,’ said Bloom and Duc Trach.
‘If not, the human genome project has the potential to widen the apartheid in health care between rich and poor countries, and between the rich and poor within countries, more profoundly than anything previously seen in medicine.’