Postmarketing studies: Methods for implementation and potential use of data

Postmarketing studies have been utilized to fulfill a variety of objectives to supplement currently available data or to establish new claims. Phase IV postmarketing evaluations are made following Food and Drug Administration (FDA) approval and may be offered by a pharmaceutical sponsor or requested by the agency to extend its evaluation of a drug's effect on a larger or more specific patient population. Official guidelines describing the proper design and conduct of these trials are lacking. An algorithmic approach to these studies is presented to help assure achievement of the study's objectives. Careful consideration must be given to defining the nature of the study relating to approved or non-approved indications and their relationship to protocol design and monitoring tchniques.