What occurs in Phase 4 of clinical trials?

Phase 4 of clinical trials is known as post-marketing surveillance. This phase occurs after a drug has been approved by regulatory authorities and is on the market. The primary purpose of this phase is to monitor the drug's long-term effectiveness and gather information regarding its risk, benefits, and optimal use in the general population.

During post-marketing surveillance, various data sources are leveraged to identify any rare or unexpected adverse events that may not have been apparent in earlier trial phases due to limited sample sizes or shorter follow-up times. This ongoing evaluation can lead to updates in drug labeling, recommendations for new uses, or even market withdrawal if significant safety concerns arise.

This phase plays a crucial role in ensuring ongoing patient safety and efficacy after a medication has been widely distributed, making it a vital part of the drug lifecycle.