The development of new treatments goes through three or four carefully monitored phases or stages.
Pre-Clinical phase
During the pre-clinical development of a drug, laboratory tests register the effect of the investigational drug in living organisms (animal testing) and in cells in the test tube. The preclinical testing results are used to find out how best to formulate the drug for its proposed clinical use. Regulatory agencies require testing that documents the characteristics – chemical composition, purity, quality and potency of the active ingredient and of the formulated drug.
By conducting toxicology studies it is possible to ascertain any potential risk to humans. All results of testing in the UK must be shown to the MHRA (Medicines and Healthcare products Regulatory Agency – government agency) or any suitable regulatory agencies in other countries so permission can be obtained to begin clinical testing in humans.
Key Activities
-
arrangement of a multi-disciplinary project team to manage the development of the compound
-
Toxicological and pharmacological screening
-
Manufacturing small amounts of the drug for testing
-
Establishing the need for a new medicine in the therapeutic area through market research
Phase 1
Assesses the safety and potential side effects of a new treatment, when given to people for the first time. Usually these treatments are tested on a small number of healthy volunteers. If it is suspected that the treatment will cause side effects it will be tested on people with the condition or disease, it is unethical to use healthy volunteers in this instance. It is also only ethical to assess a treatment or test by using human volunteers if it is believed that the treatment will give some benefit compared with no treatment or the existing treatment.
Phase 2
Looks at how well a treatment works, this phase usually follows on after Phase 1 but can also run concurrently with Phase 1. The aim is to see how effective the treatment will be against a particular disease or condition it has to be tried on people suffering from the condition.
However, the size of group tested will remain small.
Phase 3
This compares the new treatment/test against the best current available treatment using a very large group of people. This is so that the results gained will be statistically significant, because the reaction of people varies so widely to drugs and tests.
Phase 4 (optional)
These are conducted after a medicine has been granted a licence. In these studies a medicine is prescribed in an everyday healthcare environment which allows results to be developed using a much larger group of participants.
Phase 4 trials are carried out to:
- develop new treatment uses for the medicine
- compare with other treatments for the condition
- determine the clinical effectiveness of the medicine in a much wider variety of patient types in conditions of “real life”.
A major part of Phase 4 trials is safety; this often involves several thousand patients being used to detect the more rare side effects. Due to this large number of patients being studied, doctors are able to observe quality of life issues and other benefits of the medicine.
As with all phases of UK clinical trials, there are strict rules regarding the way in which Phase 4 studies are carried out. In particular, they cannot be used for anything other than a scientific purpose.
Controlled trials
A controlled trial is a clinical study that contains a comparison (control) group. This comparison group receives an alternative treatment or no treatment at all.
Randomised trials
Many trials are randomised with the aim to make a fair comparison between a new treatment and the current treatment available. They compare groups of people who are similar except for the treatment they receive.
Neither you nor your doctor will know which treatment you will receive. This is also the best way of ensuring that the results of trials are not biased. Randomised trials are seen worldwide as the most reliable way to test new treatments or compare two or more existing treatments.
Placebos
If there is no standard treatment, some people taking part in the trial may be given a dummy drug (placebo). These are used because some people get better without any treatment.
In some trials where a new treatment is being compared to a current treatment a placebo will also be used. This is because the difference may be very evident between the new and old treatment. In this case two placebos may be used that look like either drug. Again neither you nor your doctor will know whether you are being given the new, current or placebo treatment.