Drugs Trials

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Drugs Trials.

• Would You?????

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Want to earn some money??
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Thalidomide
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Thalidomide the sleeping pill
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• Thalidomide was first synthesized in West Germany
  in 1953 by Chemie Grünenthal.
• It was hailed as a "wonder drug" that provided a
  "safe, sound sleep".

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• However the drug was also found to cure morning
  sickness in pregnant women

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Nausea vomiting in pregnancy NVP 1st trimester
...(1/3)
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Foetal development -

• The first few weeks are a key period any
  problems now will accumulate in the future

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Nausea vomiting in pregnancy NVP 1st trimester
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• When do you think most women would be inclined to
  take this drug?

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Side effects

• unfortunately molecules of the thalidomide
  chemical crossed the placenta and disrupt the
  growth patterns of the growing foetus

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Effect catastrophic deformations of the baby
best seen as limb abnormalities.
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if this was you how would your life be
different?
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Why did this happen?

• Simple - the drug was not trialled or tested for
  this use on pregnant women

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Thalidomide today

• Initially the drug was banned internationally for
  the treatment of morning sickness
• But it has now been reintroduced as a treatment
  for leprosy

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Leprosy bacterial infection of the skin and
nerves endings

• Affects the hands, feet and features of the face.

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Leprosy
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Drug testing sequence How are new
drugs developed?
? Pfizer Ltd
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Synthetic chemicals?
First tests in laboratory
Traditional remedies?
Drug Development and Testing
Which diseases to treat?
Animal testing
Phase I Testing on students!
Phase III Final tests and licensing
Phase II Testing on patients
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Which diseases to treat? Doctors, politicians,
drug company executives, members of the public
and scientists all have an opinion. At some point
money will be made available for the research
into a disease cure to begin.
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Traditional remedies? Where to start? Sometimes
researchers will look at traditional remedies
to see if there is anything to learn. Plants,
animals, bacteria and fungi have all been used as
sources for new medicines.
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• Synthetic chemicals?
• Chemists produce a wide range of new chemicals
  every year. Many are screened for useful medical
  effects. Sometimes chemists use computer models
  to design a molecule which should cure an
  illness. Then they try to make it in the
  laboratory to see if it works as predicted.

? Pfizer Ltd
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First tests in laboratory The first level of
testing uses cell cultures or body parts (in
vitro screening). The potential medicine is
tested thoroughly to answer the questions Is it
toxic (poisonous)? and Does it work?
? Pfizer Ltd
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Animal testing The few chemicals that pass the
first stage move on to whole animal testing. We
think the drug is safe but we need to check. At
this stage scientists also learn about how the
drug works in a living body.
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Phase I Human trials testing on volunteers The
(very few) chemicals that pass the animal testing
stage move on to the first human tests. These are
done on healthy people often students who get
paid a small amount of money for volunteering.
This stage checks the safety of the drug and
looks for side effects. Animal tests continue,
looking for any long term effects.
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Phase II Testing on patients The first ill
people to get the drug are the Phase II
volunteers. This is where scientists can really
begin to see if the drug will be safe and
effective.
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Phase III Final tests and licensing If all goes
well with phase II the trials move to phase III.
Many more people are given the new drug. Some of
the people in the phase III trial will be given
dummy treatment so that doctors can compare the
effect of the drug with already available
medicines or nothing at all. By the end of a
successful phase III the drug company submits its
research to government bodies to ask for a
licence to sell the drug.
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Even once a medicine has been licensed for use it
is still watched carefully for unexpected
problems. These phase IV trials, where doctors
report on any side effects suffered by their
patients, continue as long as the medicine is
used. Phase IV trials can involve hundreds of
thousands of people.
Sometimes the trials throw up unexpected problems
- medicines can even be withdrawn from use
because serious problems appear! A drug company
may decide to develop a new drug to replace the
original one because it has fewer side effects.
The whole process begins again!
? Peninsula Medical School