Reporting of prior clinical studies in Investigator's Brochures did not adhere to the basic principles of evidence synthesis: a cross-sectional study.

Objectives: International regulations require Investigator's Brochures (IBs) to compile all available evidence that inform the risk-benefit assessment for the newly planned clinical trial. This study examined the adherence of IBs to the basic principles of evidence synthesis when compiling prior clinical studies.

Study Design And Setting: For 97 IBs for phase I/II trials reviewed at one German research ethics committee we assessed the reporting on search, appraisal, and synthesis procedures for prior clinical studies. For a random subsample of 30 IBs, we evaluated the quality of reporting of the compiled 247 prior clinical studies.

Results: Only 2% of all 97 IBs reported a comprehensive search strategy, provided a critical appraisal of the compiled prior clinical studies or presented respective study results in a structured manner. For the 247 prior clinical studies compiled in 30 IBs, the information required to appraise their risk of bias (eg, sample size calculation or baseline characteristics) was rarely reported.

Conclusion: When compiling all available evidence supporting the rationale for the proposed clinical study IBs do not acknowledge the broadly established principles for reviewing and reporting evidence. This may impact negatively on the trustworthiness and efficiency of risk-benefit assessment.