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PHARMA: Patients should not be too enamoured by the idea of personalised
medicine as it comes at a cost, warns Donna Dickenson
DOES
personalised medicine cut the mustard when it comes to treating cancer? Richard
Smith, a former editor of the British Medical Journal, believes that it does
not. Using the mustard metaphor, he shows how personalised medicine undermines
the pharmaceutical industry's profits. If the one-size-fits-all approach to
prescribing cancer drugs were abandoned, drug companies would be forced to
change their business model, most notably by increasing prices radically -- or
stop producing the drugs altogether.
In
pharmacogenetics (or pharmacogenomics), genetic typing is used to determine a
patient's likely response to drugs, and to tailor the pharmaceutical regime
accordingly. In oncology, this means adjusting treatment based on the cancer's
sequenced genome, which differs from that of the patient's normal cells. It
might be possible, for example, to identify patients who are genetically
programmed to respond more quickly to chemotherapy, and thus to prescribe lower
dosages that allow them to avoid the treatment's worst side effects.
This
approach is crucial in oncology, given that cancer varies widely, even in
patients with the same diagnosis. After sequencing 50 patients' breast cancers,
one group of researchers found that only 10 per cent of the tumours had more
than three mutations in common.
Likewise,
an analysis of biopsies conducted on four patients with kidney cancer showed
that a single tumour can have many different genetic mutations at various
locations. Two-thirds of the genetic faults identified were not repeated in the
same tumour, let alone in any other tumours that appeared elsewhere in the
patients' bodies. A pharmacogenomic drug that targets one mutation may not work
on others.
If a
pharmaceutical company treats 100 patients for STG100 (RM488) each, it makes
STG10,000. But, if only 10 of those patients -- 10 per cent of tumours -- are
genetically programmed to benefit from the drug, insurers or national-health
systems will want to pay only for those patients, reducing the company's income
by 90 per cent. This is where the mustard metaphor comes in.
According
to Smith, drug companies are like mustard makers. They make most of their money from patients who do not benefit from the drugs
that they provide, just as mustard makers profit primarily from what diners
leave on their plates.
Stratified
or personalised medicine will require drug companies to raise their prices
significantly in order to offset losses from the reduction in portions.
In
fact, this is already happening. A new
personalised drug for cystic fibrosis, Kalydeco, is highly effective, but only in the
four per cent of patients who have a particular genetic mutation. As a result, one year of treatment costs US$294,000
(RM894,000). Likewise, Xalkori is being made available for US$9,600 per month,
because the drug's target population -- patients whose lung cancers have a
certain mutation -- comprises fewer than 10,000 patients.
In
the United Kingdom, the National Health Service deemed the personalised cancer
drug Herceptin too expensive, until a public outcry forced the NHS to reverse
its position. But, in an age of austerity, will the authorities do so again?
By
restricting access to the rich and the well insured, rising drug costs could
exacerbate growing inequality in many countries. As the healthcare ethicist
Karen Peterson-Iyer has pointed out: "From the standpoint of justice, one
of the most disturbing possibilities raised by pharmacogenetics is that it will
further entrench the already deep socioeconomic divisions that characterise
modern US society."
But
personalised medicine is not the only factor undermining the pharmaceutical
industry's profits. Patents on many best-selling drugs are expiring, deepening
the urgency of finding new markets.
Pharmaceutical
companies can create new niche markets by persuading customers that they cannot
rely on a one-size-fits-all product, and by breaking down existing medications
into different "size ranges".
Their
best option would be to persuade individual patients to pay out of their own
pockets to learn which of the niche pharmaceuticals is their "size".
Now that an entire genome can be sequenced for only US$1,000, online
direct-to-consumer genetic firms may well extend their reach from gene subsets
to whole-genome mapping.
In
this case, diagnostic costs would be transferred from the public-health system
or insurers to the individual. But that could lead to new problems,
particularly if some individuals are excluded from coverage on the basis of the
genetic profile for which they have paid.
Moreover,
even if pharmaceutical companies raise prices, there will probably be some
combinations of pharmacogenetic drugs for which the market is simply too
limited. Patients with cancers driven by different genetic pathways would
require such diverse drug combinations that producing every drug required for
each patient's ideal regime would not be feasible.
Indeed,
as medicine becomes more personalised, the range of customers for each drug
narrows, weakening pharmaceutical companies' incentive to produce them.
Personalised
medicine appeals to our desire for choice and autonomy. But we should be
careful what we wish for. Patients' enthusiasm for pharmacogenetics would be
dampened significantly if it served as a rationale for national health systems
and insurers to deny them treatment. And, with governments and companies
worldwide cutting costs, that may well be the shape of things to come. Project
Syndicate
Donna Dickenson is Emeritus Professor
of Medical Ethics at the University of London. Her book on personalised
medicine, ‘Me Medicine vs We Medicine’, will be published in the spring of this
year.
