Phase IV Clinical Trials
Phase IV clinical trials are the final step in the drug discovery process. Also referred to as post-marketing studies, these trials study drugs that have already received approval by the relevant governing body and have reached the market. The governing body here can include the TGA in Australia, the FDA in the United States of America, or the MHRA in the United Kingdom. As these drugs have reached the market, they are available for prescribing, or to be sold in an over the counter (OTC) setting in pharmacies. Phase IV clinical trials are conducted to assess the efficacy of a drug in a ‘real-world’ setting, as this is often vastly different to the highly controlled environment of a Phase III trial where the drug was previously studied. These trials can also be used to assess the efficacy of a drug on different age groups, different populations, and make comparisons between other drugs on the market. Phase IV clinical trials are used to assess the long-term safety profiles of drugs, and side effects that may present in only a small percentage of the population. Pharmaceutical companies may also conduct Phase IV trials to assess the economic use of the drug, specifically to assess whether the drug is profitable. Trials may also investigate the use of the drug with other products to assess its safety and efficacy when used in combination with others. Phase IV clinical data is used to complement data from Phase I, II, and III trials.
Learning Objectives
- Discuss the primary purpose of Phase IV in clinical trials
- Describe how Phase IV clinical trials evaluate the efficacy and safety of new drugs
- Understand how phase IV clinical trials influence economic outcomes
- Summarize the clinical trials phases