Italy was used as a case study to investigate the determinants of the difference between the price proposal for medicines submitted by the industry and the final negotiated price (∆P). Data was gathered through the information system used by Italian Medicines Agency (AIFA) and the time-frame for this analysis is 2013-2017. Factors influencing the delta price were analyzed through a regression analysis. Forty four orphan drugs and 89 new other molecular entities obtained reimbursement in the period considered. Following the negotiation process, prices proposed by Marketing Authorization Holders (MAH) were lowered during the negotiation process by 25.1% and 28.6% on average for orphan drugs and other molecules respectively. The price reduction was higher for innovative drugs (-32.2%). Statistically significant determinants associated to higher price reduction were: i) the implementation of a product specific monitoring registry, ii) the negotiation of a financial-based (FB) Managed Entry Agreement, iii) a target population larger than 20,000 patients, iv) an expected National Health Service expenditure larger than € 200 million. The impact of some variables on the delta price was predictable (e.g. for drugs with an expected higher budget impact and a larger target population), others were more surprising (e.g. a significant price reduction for "innovative" drugs). The implementation of FB agreements, which often rely on confidential arrangements, was one of the determinants with higher impact on price reduction.