OBJECTIVES: Immune checkpoint inhibitors (ICIs) have enjoyed considerable clinical and commercial success since their launch, and now account for a significant and growing proportion of drug budgets. This study assessed payer attitudes towards the reimbursement of ICIs and explored current and future expenditure control strategies in the five major EU markets (France, Germany, Italy, Spain, and the UK) (5EU). METHODS: 14 payers in the 5EU were interviewed in Q4 2018 regarding the current and future ICIs pricing and reimbursement landscape. Health Technology Assessment (HTA) and pricing decisions for ICIs in the 5EU were also analysed. RESULTS: Price-volume and budget ceiling agreements are the most common cost-control measures utilised across Europe. Following approvals in expanded patient populations, payers require price reductions for ICIs or new price-volume agreements due to increased patient numbers and related budget impact. Payers would like to leverage the growing competition in the ICI space to manage costs, but highlight that preferential contracting/tendering is unlikely to occur until there is a more saturated market with a larger number of overlapping indications in more prevalent diseases. Looking forward, payers stress the need for more sophisticated tools to control the budget impact of high-cost combination regimens. This is especially relevant when the components of a combination regimen are produced by two different manufacturers, as payers currently lack the ability to bring both manufacturers into joint pricing negotiations. Payers in Europe expect new tools to emerge in the next 1-3 years. CONCLUSIONS: Payers will continue to use the full arsenal of current mechanisms available to control ICI drug budget impact. New tools will be developed to track the usage and minimize the drug budget impact of high-cost combination regimens, and ensure their use is factored into individual price negotiations for both existing therapies seeking label expansion as well as new therapies.