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Development of medicines
Researching New Medicines.
Clues about the nature of illness
and possible avenues of prevention
or treatment come from many sources.
Doctors' experience with patients,
world-wide patterns of disease,
research on living cells and tissues
as well as fundamental research
with mammals, fish and reptiles
and even insects and plants all
provide pieces of a giant jigsaw
puzzle. The understanding that leads
to medical progress depends on being
able to put these often seemingly
unrelated pieces together.
Once researchers have a theory,
they must test its value, because
even the most promising theories
often prove to be wrong. Despite
big advances in the understanding
of how our bodies work, many aspects
of even our most basic body processes
remain a mystery. As our own biology
has so much in common with that
of other animals, research with
animals has taught us things we
could not have discovered in any
way, other than by experimenting
directly in humans.
Modern research
and development of new medicines
uses the most up-to-date technology
From the earlier research, scientists may believe that a particular type of compound could be a useful medicine for a particular illness. Then the long process of research and development begins, usually taking about 12 years. For many medicines, computers have revolutionised the early stages because they can design thousands of variations of molecules quickly and work out which ones have promise based on what is already known about various types of chemical structures.
Computers are also an essential
tool because they are used, in conjunction
with state-of-the art robotic systems,
to search huge 'libraries' of compounds
for any that might have helpful
biological activity - for instance,
ones that react with a particular
protein involved in a particular
illness.
Armed with the information from
computers, scientists select compounds
that must then be tested. Some of
this work can now be done on cells
in the test tube. The effect of
the compounds on these isolated
cells gives some indication of their
usefulness. Those compounds that
are obviously going to ineffective
or harmful are eliminated at this
early stage. Only a relatively small
number of compounds will get through
this stage. But for those that remain,
it is still early days in the research
process.
Ultimately
it's what happens in the whole body
that counts.
In the end, however, the usefulness
of a medicine will depend on less
obvious effects on the whole body,
not just on cells in isolation.
So new medicines have to be tried out on complete living systems, first in animals and then in people. Animals, despite obvious and not so obvious differences, have biological systems that are very similar to our own. Some have argued that the differences are too great for the use of animals to be justified. But researchers know from long experience that most effects of medicines can be seen in animal tests, provided those tests are carefully designed, properly conducted and evaluated.
Knowing this, it is hard to imagine
a society that would allow medicines
to go straight from the test tube
into patients. It is important to
note that decisions about the approval
of a new medicine for doctors to
prescribe are never made on the
basis of animal studies alone. All
medicines must eventually be tested
in people, but only after those
who have the responsibility of making
these decisions are confident that
it is safe enough to do so. If,
after lengthy human trials, the
benefits of a medicine significantly
outweigh the risks, the Government's
Committee on Safety of Medicines
will recommend its approval.
Once a medicine becomes available,
its use must still be monitored.
The numbers of people taking it
are likely to be many times greater
than could ever be included in the
clinical trials in patients. So
it is always possible that unpredicted
side effects will be seen. Usually
these are minor. But very occasionally,
serious problems develop. Each case
is different and is carefully studied
to see if there are improvements
that could be made in the research
process to avoid the situation in
the future.
But no combination of research methods can guarantee a medicine's safety for every single person that may take it, nor that it will work for every individual. Scientists do the best they can, using a combination of all the available testing methods, to make new medicines as safe and effective as possible.
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