Phase IV Clinical Trials → Efficacy

Phase IV clinical trials can reveal the ‘real-world’ effectiveness of a therapy and complement data from previous phase randomised controlled trials (RCTs) before the therapy reached market. As these studies occur in an uncontrolled environment, they can reveal the efficacy of a therapy when participants are able to go about their lives as normal. This can include changing their diet, smoking habits, or use of other medications, which may alter the effects of the therapy. The aim of these studies is to demonstrate the effectiveness shown in RCTs in phase III is comparable to that in a ‘real-world’ setting. Phase IV clinical trials can demonstrate the long-term effectiveness of the therapeutic, and assess whether the therapy meets its original goals i.e. if a drug was shown to prevent cancer recurrence, does it extend life? Post-marketing studies can also evaluate the efficacy of a therapy in a patient subgroup, or in special situations.