At a glance
WHAT IS A CLINICAL TRIAL?
A clinical trial is a research study on human participants to determine whether a treatment is safe and effective. It aims to answer three key questions:
- Does the treatment work?
- Does it work better than other treatments for the same condition?
- Is it safe for different groups of patients?
Clinical trials are monitored by outside experts to safeguard participants’ health. Treatments go through several clinical trial ‘phases’ – I-IV – to track safety and effectiveness before and after being approved.
INTERVENTIONAL TRIALS
In interventional trials, participants are assigned to groups that receive either a treatment or a placebo (i.e., a ‘lookalike’ treatment that contains no actual treatment). Interventional trials allow researchers to evaluate the health and safety effects that are specifically caused by the treatment.
OBSERVATIONAL STUDIES
Observational studies do not involve providing new treatments to patients; instead, they aim to understand how participants behave in ‘real world’ settings by studying how people respond to the medications they are already taking. These studies give scientists a more realistic idea of the factors influencing patients’ health and treatment.
Phases of clinical trials
Researchers conduct clinical trials in phases, I through IV.
Phase I
Phase I tests are primarily concerned with testing the safety of a medicine, so are conducted on a small group of – usually healthy – participants. In some case, like cancer treatments, the treatments are very powerful and so the Phase I trials go directly to patients.
Phase II
In Phase II, participants who have the actual disease condition receive the treatment in order to test the safety and effectiveness of the new treatment in improving their condition.
Phase III
In Phase III, larger groups of participants receive the treatment to confirm its effectiveness and safety. Phase III trials often compare the new treatment with other available ‘standard of care’ treatments.
Phase IV
Phase IV trials track the effects of long-term use and commonly reported side effects of a treatment after it is licensed for use by the public.