Company observational post-marketing studies: drug risk assessment and drug research in special populations – a study-based analysis

Abstract

Objectives: Company observational post-marketing studies (COPS) claim to provide essential data about drug risks and effectiveness in special populations not admitted to pre-approval clinical trials. Since COPS are often mainly regarded as a marketing activity, this study-based analysis tries to evaluate the scientific contributions of COPS.

Material and methods: Thirty-five COPS were identified by hand-searching through medical journals, writing to pharmaceutical manufacturers and using MEDLINE. Fourteen COPS evaluated cardiovascular drugs, 9 evaluated NSAIDs and 12 evaluated various other indications.

Results: Thirty-five COPS listed effectiveness, 31 listed safety and 8 listed patient compliance as principal objectives. Not a single COPS included a control group. Seventeen of 21 evaluable COPS mentioned extensive exclusion criteria similar to those in clinical trials. Median observation time was 8 weeks, too short for chronic diseases and for adverse drug reactions with longer latency periods. One new adverse event was regarded. Global assessments of the outcomes by physicians dominated and were not based on objective clinical findings. None of the studies specified any details concerning the standardisation of observations or quality-control procedures.

Discussion and conclusion: The current COPS scheme does not contribute significantly to our knowledge of drug safety and the effects in special populations. Despite serious criticism over the past 20 years, the poor quality of COPS – compared with dramatic improvements of pre-approval trials – implies a need for detailed guidelines for non-experimental phase IV research, similar to the Good Clinical Practice-Guideline of the European Community.