OBJECTIVES: Italy was among the first European countries to adopt performance-based managed entry agreements (PB-MEA). Drug monitoring registries monitor PB-MEA drug performance and contain per patient clinical treatment pattern and outcome information. An algorithm validates prescriptions, selects treatments eligible for PB-MEA. In Italy, 126 drugs are subject to PB-MEA, therefore complying with registries is becoming increasingly complex and burdensome for clinicians. The objective of this study is to identify the gap between refundable charges, due by manufacturers and refunded charges at G. Martino” University Hospital in Messina, as well as to propose actions to minimize the gap through clinical pharmacist engagement. METHODS: Clinical pharmacists analysed monitoring registries for oncology and hemato oncology prescribed drugs from January 2012 to December 2015 to identify the amount due by manufacturers to the hospital and the amount actually refunded according to PB-MEA. Hospital pharmacists and clinicians supported the case assessment of the drug performance. Analysis was retroprospective: retrospective (January 2012 – August 2014) and prospective (September 2014 – December 2015).RESULTS: We identified 293 case of oncology and 153 cases for hemato oncology of which 215 and 119, were captured during prospective phase. “Disease Progression” for oncology and “Not-drug-related reasons” for hemato-oncology were the main causes for drug discontinuation. In the analysed period, eligible reimbursements were €480,478 while €71,213 were not reimbursed due to avoidable errors in the registry filling. Intervention of clinical pharmacists allowed identifying a list of actions to minimize this gap. CONCLUSIONS: PB-MEA is forecasted to further grow in Italy. The burden and complexity of registries filling lead to loss of refund of about 10%. Clinical pharmacists’ engagement may contribute to reduce the gap and improve efficiency. At the time health care systems face severe cost-containment measures and demand increases, ensuring a better efficiency of health care providers is critical.