Prices and prescribing of competing cancer medicines in Dutch hospitals after imatinib loss of exclusivity: a retrospective claims analysis

Background When the first product in a therapeutic class loses market exclusivity, generic entry reduces price and spending for the off-patent medicine. In classes with close substitutes, a lower-priced benchmark may affect the value of remaining on-patent alternatives. Whether this leads to price convergence or prescribing shifts remains sparsely documented. Objective To describe spending and utilisation of competing tyrosine kinase inhibitors (TKI) in Dutch hospitals following loss-of-exclusivity (LoE) of imatinib, the first-in-class drug to treat chronic myeloid leukaemia. Methods We analysed health insurance claims from all Dutch insurers over 2013 – 2022, covering the period before and after imatinib’s LoE in 2017. Outcomes were average reimbursement per treated patient-year, total spending, and patient-count based market shares for imatinib, dasatinib, and nilotinib. Results From 2017 to 2022, total spending on imatinib declined by 95%, while per-patient reimbursement fell by 89%. Imatinib’s market share decreased from 54 to 48% (2013–2022), while the market share of on-patent alternatives rose by the same amount. Per-patient reimbursement for on-patent alternatives showed none or very limited convergence towards the benchmark. Conclusions Following the LoE of a competing TKI, prices of the remaining on-patent TKIs used in Dutch hospitals did not decline, substantially worsening their cost-effectiveness relative to the generic alternative. Limited price convergence and minimal redistribution of market shares meant that substantial potential savings for payers remained unrealised. Payers and policymakers should reassess prices, contracting arrangements, and value assessments against post-LoE benchmarks and actively facilitate clinically appropriate prescription of alternative medicines.