Review of company postmarketing surveillance studies.

OBJECTIVES

To review postmarketing surveillance studies sponsored by the pharmaceutical industry since the introduction of voluntary guidelines in 1987 and to evaluate their contribution to monitoring drug safety.

DESIGN

Retrospective analysis of the information submitted to the Medicines Control Agency on postmarketing surveillance studies.

SETTING

United Kingdom.

MAIN OUTCOME MEASURES

Study designs, projected and actual sample sizes, provision of interim and final reports, number of suspected serious adverse reactions reported, identification of new drug safety hazards.

RESULTS

31 studies had been conducted under the guidelines, of which 27 were prospective and four retrospective. Nine studies had at least one comparator group, the remainder were uncontrolled. The median projected sample size for the studies was 5600 patients. Only five studies had achieved at least 75% of the projected sample size. 11 studies had been abandoned, predominantly because of difficulties in recruitment, and 15 were ongoing. One study had identified an important new safety hazard.

CONCLUSIONS

Company postmarketing surveillance studies have made only a limited contribution to the assessment of drug safety, principally because of weak study designs and difficulties in recruitment. The guidelines require modification to take this experience into account.