Study design, process and outcome indicators of post-authorization studies aimed at evaluating the effectiveness of risk minimization measures in the EU PAS Register.

Risk minimization measures (RMMs) represent an essential tool for preventing the occurrence of safety-related outcomes. The evaluation of RMMs effectiveness is essential to prove their success and ensure protection of public health. The aim of this qualitative review was to assess the design, process and outcome indicators used for attesting successful implementation of RMMs. We searched the EU Post-Authorization Studies Register up to 30 June 2018 for studies having the scope defined as 'effectiveness evaluation'. Study titles and objectives were screened to select the ones evaluating the effectiveness of RMMs. We described and assessed the extent to which these studies aligned with Good Pharmacovigilance Practices guidelines recommendations. Out of 360 registered studies, we identified 35 studies on evaluation of RMMs effectiveness, 29 being eligible for review. Twenty-six studies evaluated additional RMMs, employed in case routine interventions are considered insufficient. All studies assessed process indicators, five also assessing outcome indicators, thus using a dual-evidence approach as recommended by the guidelines. However, none of the latter used a pre-post design, comparing the frequency of the adverse outcome before and after the implementation of RMMs. Behaviour and knowledge were the most often assessed process indicators. Outcome indicators included occurrence of adverse reactions, pregnancy, off-label use and medication errors. Only four studies had an established threshold, all for process indicators. Stricter adherence to existing recommendations would allow for a more robust design for reaching established endpoints for RMM effectiveness evaluation. It would also infer harmonization, facilitate review and further more detailed guidance on conducting these studies.