Clinical Trials and Drug Testing
Historic Drug Testing
• William Withering was a scientist in the 1700s.
• He discovered that an extract of foxgloves could be used to treat dropsy (swelling brought about by heart
failure). This extract contained the drug digitalis.
• Withering made a chance observation – a patient suffering from dropsy made a good recovery after being
treated with a traditional remedy containing foxgloves.
• Withering knew foxgloves were poisonous, so he started testing different versions of the remedy with
different concentrations of digitalis – this became known as his digitalis soup.
• Too much digitalis poisoned his patients, while too little had no effect.
• It was through this crude method of trial and error that he discovered the optimum dosage to give to a patient.
Modern Drug Testing
Pre-Clinical Testing
• Consists of laboratory studies on isolated cells and tissue cultures.
• Assesses the safety and determines whether the compound is effective against the disease.
• Can take several years to complete.
Clinical Trials – Phase 1
• Involves testing a new drug on a small group of healthy individuals (can be tested on patients in some cases).
• Confirms how the compound interacts with the human body, including side effects, and the effects of different
doses are monitored.
• Typically takes several months to a year.
Clinical Trials – Phase 2
• Involves testing the drug on patients and on a larger scale – around 100-300 people.
• Tests how effective the drug is and assesses appropriate dosing levels.
• Typically takes around 2 years.
Clinical Trials – Phase 3
• Involves testing the drug on a very large group of patients – around 1000-3000 people, and comparing the
drug to existing treatments.
• Demonstrates the safety and effectiveness of the drug, confirms effective dosing levels, identifies side effects
and builds knowledge on the benefits and risks of the treatment.
• Involves the use of a placebo in a double-blind trial.
• Typically takes several years.
Placebo:
• In phase 2 and 3 clinical trials, the patients are split into two groups: one group is given the drug and the other
is given an inactive substance that looks like the drug – a placebo.
• Patients often show a placebo effect – they show some improvements because they believe they are receiving
treatment.
• Placebos allow researchers to determine whether the drug is actually having an effect.
• It can be considered unethical to give a patient a placebo, when they could be given something that is likely to
improve their condition, however there is no guarantee that the drug is as effective as current treatments.
Double Blind Tests
• Phase 2 and 3 clinical trials are usually double blind – neither the patients nor the doctors know who’s been
given the drug and who’s been given the placebo (or old drug).
• This reduces bias in the results because the attitudes of the patients and doctors can’t affect the results.
How is Modern Drug Testing Safer than Historical Methods?
• Modern drug testing involves preliminary tests on isolated cells and tissue culture.
• Modern drug testing involves testing on healthy individuals before patients to reduce the risk to patients.
17
Historic Drug Testing
• William Withering was a scientist in the 1700s.
• He discovered that an extract of foxgloves could be used to treat dropsy (swelling brought about by heart
failure). This extract contained the drug digitalis.
• Withering made a chance observation – a patient suffering from dropsy made a good recovery after being
treated with a traditional remedy containing foxgloves.
• Withering knew foxgloves were poisonous, so he started testing different versions of the remedy with
different concentrations of digitalis – this became known as his digitalis soup.
• Too much digitalis poisoned his patients, while too little had no effect.
• It was through this crude method of trial and error that he discovered the optimum dosage to give to a patient.
Modern Drug Testing
Pre-Clinical Testing
• Consists of laboratory studies on isolated cells and tissue cultures.
• Assesses the safety and determines whether the compound is effective against the disease.
• Can take several years to complete.
Clinical Trials – Phase 1
• Involves testing a new drug on a small group of healthy individuals (can be tested on patients in some cases).
• Confirms how the compound interacts with the human body, including side effects, and the effects of different
doses are monitored.
• Typically takes several months to a year.
Clinical Trials – Phase 2
• Involves testing the drug on patients and on a larger scale – around 100-300 people.
• Tests how effective the drug is and assesses appropriate dosing levels.
• Typically takes around 2 years.
Clinical Trials – Phase 3
• Involves testing the drug on a very large group of patients – around 1000-3000 people, and comparing the
drug to existing treatments.
• Demonstrates the safety and effectiveness of the drug, confirms effective dosing levels, identifies side effects
and builds knowledge on the benefits and risks of the treatment.
• Involves the use of a placebo in a double-blind trial.
• Typically takes several years.
Placebo:
• In phase 2 and 3 clinical trials, the patients are split into two groups: one group is given the drug and the other
is given an inactive substance that looks like the drug – a placebo.
• Patients often show a placebo effect – they show some improvements because they believe they are receiving
treatment.
• Placebos allow researchers to determine whether the drug is actually having an effect.
• It can be considered unethical to give a patient a placebo, when they could be given something that is likely to
improve their condition, however there is no guarantee that the drug is as effective as current treatments.
Double Blind Tests
• Phase 2 and 3 clinical trials are usually double blind – neither the patients nor the doctors know who’s been
given the drug and who’s been given the placebo (or old drug).
• This reduces bias in the results because the attitudes of the patients and doctors can’t affect the results.
How is Modern Drug Testing Safer than Historical Methods?
• Modern drug testing involves preliminary tests on isolated cells and tissue culture.
• Modern drug testing involves testing on healthy individuals before patients to reduce the risk to patients.
17
