Clinical trials

purpose of clinical trials - 3

• safety - test for side effects

• effectiveness/ efficacy

• dosage - too high of a dosage may be toxic

When designing clinical trials there are three main protocols that are used:

• randomised

• placebo-controlled

• double-blind

How and why do we randomise trials

• Participants in clinical trial are split into different groups entirely at random. computer programme may be used.

• Reduces possible bias in the trial e.g. same ages/ same gender

Placebo-controlled

A placebo is a 'dummy' treatment with no medical or therapeutic value. A placebo looks like the drug being tested but only contains sugar.

One group of participants will be given the drug and another control group will be given the placebo. It is important that participants are not aware of which group they are in. Following the completion of the trial, results will be compared.

Double-blind

In a double-blind trial, neither the participants nor the researchers are aware which group has been given the drug and which group has been given the placebo. This also reduces bias when interpreting the results.

Stage 1 of drug testing: Lab

• drugs tested using skin cells made by human stem cells in the lab.

• Allows efficacy and possible side-effects to be tested.

Stage 2: Animal trials

• Drugs that pass the first stage are tested on animals in the second part of a preclinical drug trial.

• a typical test involves giving a known amount of substance to the animals, then monitoring them carefully for any side-effects.

Stage 3: human clinical trials

1. Tested on human volunteers to check that they are safe.

2. Then tested on people with the illness to ensure they are safe and that they work.

   • Low doses of the drug are used initially, and if this is safe the dosage increases until the optimum dosage is identified.