Why would a Phase IV study be conducted?

Phase IV studies (post-marketing) examine real-world safety and effectiveness.

ICH E8(R1):Describes Phase IV as “studies performed after drug approval to delineate additional information including the drug’s risks, benefits, and optimal use.”

They often test drugs innew or broader populationsbeyond original approval.

While dosing and schedules are Phase I–III, Phase IV focuses onnew patient populationsor long-term outcomes.