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.
References:ICH E8(R1).