Biology 1 Testing drugs

Drugs Trials……. Would You?????

Biology 1 Testing drugs Want to earn some money?? Two thousand pounds only 2,000 6 th July 2007 S. Martin Fred Bloggs

Biology 1 Testing drugs

Thalidomide

Biology 1 Testing drugs Thalidomide – the sleeping pill

Biology 1 Testing drugs 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".

Biology 1 Testing drugs However the drug was also found to cure morning sickness in pregnant women

Biology 1 Testing drugs Nausea vomiting in pregnancy NVP – 1 st trimester...(1/3)

Biology 1 Testing drugs Foetal development - The first few weeks are a key period – any problems now will accumulate in the future

Biology 1 Testing drugs Nausea vomiting in pregnancy NVP – 1 st trimester (1/3) When do you think most women would be inclined to take this drug?

Biology 1 Testing drugs Side effects unfortunately molecules of the thalidomide chemical crossed the placenta and disrupt the growth patterns of the growing foetus

Biology 1 Testing drugs Effect = catastrophic deformations of the baby– best seen as limb abnormalities.

Biology 1 Testing drugs …if this was you – how would your life be different?

Biology 1 Testing drugs

Why did this happen? Simple - the drug was not trialled or tested for this use on pregnant women

Biology 1 Testing drugs 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

Biology 1 Testing drugs Leprosy – bacterial infection of the skin and nerves endings Affects the hands, feet and features of the face.

Biology 1 Testing drugs Leprosy

Biology 1 Testing drugs  Pfizer Ltd Drug testing sequence How are new drugs developed?

Biology 1 Testing drugs Synthetic chemicals? First tests in laboratory Animal testing Phase I: Testing on students! Phase II: Testing on patients Phase III: Final tests and licensing Which diseases to treat? Traditional remedies? Drug Development and Testing

Biology 1 Testing drugs 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.

Biology 1 Testing drugs 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.

Biology 1 Testing drugs 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

Biology 1 Testing drugs 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

Biology 1 Testing drugs 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.

Biology 1 Testing drugs 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.

Biology 1 Testing drugs 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.

Biology 1 Testing drugs 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.

Biology 1 Testing drugs 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