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"Companies, if they want to survive, if they want to remain
competitive in 3-5 years time, need to be investing in pharmacogenetics
- its use will be widespread," Professor Allen Roses, VP and
Director of Worldwide Genetics at Glaxo Wellcome, told IMS
HEALTH Companies during an interview in June 2000.
Roses defines pharmacogenetics (as distinct from pharmacogenomics
- any use of genomics or proteomics technology in drug discovery
and development) as the study of how genetic differences influence
the variability in patient's responses to drugs.
Through the use of pharmacogenetics, we will soon be able
to profile variations between individuals' DNA to predict
responses to a particular medicine. "The timeframe for pharmacogenetics
is quite short - it is sneaking up on the pharmaceutical industry.
Its impact has not hit industry analysts or commercial people
yet."
Potential uses of pharmacogenetics
The study of pharmacogenetics can be used to determine whether:
- an individual is likely to respond to a medicine
- will experience side effects.
Eleven Americans die each hour due to drug-related side effects,
according to the genomics company Celera. Some 6.7% of people
prescribed drugs have a severe adverse reaction, with drug-related
side effects being the fifth leading cause of death in the
US in 1997 (CDC, 2000).
Moreover, for a number of serious diseases, current drug therapy
is significantly toxic to healthy as well as diseased cells.
Pharmacogenetics can help identify alternative drug therapies
that reduce this toxicity for subclasses of patients.
In rheumatoid arthritis for example, scientists recently discovered
that for certain genetic subclasses, therapy with a single
class of drugs was as effective as a highly toxic combination
of three drugs.
Economic benefits to R&D
The use of pharmacogenetics has the potential to affect
dramatic improvements in the quality of a company's clinical
development portfolio in the following ways:
- Enhanced phase I/II screening - with pharmacogenetic
screening, individual compounds would be more likely to
be dropped in phase I, but those making it through would
have a higher overall chance of success.
- The number of patients in small-scale trials, particularly
phase II, could be reduced by as much as half - with small
sample sizes, it would be possible to double the statistical
power of a test through preselection of patients with
higher drug response.
According to a report by McKinsey & Company, costs per compound
typically run at $7 million in phase I, but jump to $43 million
in phase III. A pharmaceutical company could save about $36
million in costs by abandoning a compound at the earlier stage
of development.
Future implications for healthcare
According to Allen Roses, the application of pharmacogenetics
to the delivery of medicines will maximise the value of each
medicine - medicines will be prescribed only to those patients
where a high probability of efficacy without significant adverse
events is expected.
Health care delivery will improve and the need for rationing
will be eliminated. "The practise of pharmacogenetics will
result in the right drug for the right patient," concluded
Roses.
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