BACKGROUND: Compassionate use programs (CUP) for medicines respond to the ethical imperative of providing earlier access to medicines to patients not recruited in trials. While the economic impact of clinical trials has been already investigated, no evidence on the net economic benefit of CUP exists. This research aims to fill the information gap by estimating the economic consequences of 11 CUP in Italy conducted between May 2015 and December 2020 from the perspective of health care payers. Eight programs concern cancer treatments, two refer to drugs for spinal muscular atrophy, and one is indicated for multiple sclerosis.METHODS: The net economic benefit includes the avoided costs from the Standard of Care (SoC) the patients would have received if they had not joined the CUP, and costs not covered by the pharmaceutical industry but instead sustained by payers, such as those associated to adverse events (only severe sides effects resulting in hospitalisation and attributed to CUP medicines), and costs for combination therapies and diagnostic procedures not used with the SoC. The SoC costing relied on publicly available data. Information on adverse events and diagnostic procedures was retrieved from the CUP and monetized using the relevant fee for episode or service. One CUP was excluded since a SoC was not identified.RESULTS: 2,712 patients were treated in the 11 CUP, where SoC was identified. The SoC mean cost per patient ranges from €11,415 to €20,299. The total cost of the SoC ranged between €31.0 and €55.1 million. The mean cost per patient covered by hospitals hosting CUP was equal to €1,646, with a total cost of €4.5 million. The net economic benefit ranged from €26.5 million to €50.6 million (€17.8 million - €42.0 million for cancer treatments). CONCLUSIONS: Despite research limitations, this paper illustrates for the first time the net economic impact of CUP in oncology patients from a payer perspective. It is important to integrate these estimates with the prospective effects of CUP implementation, i.e., the economic value of the comparative benefit profile of medicines used in CUP versus the SoC, including effects from a societal perspective.