Medical Dermatology

Aims:Although there is a growing body of evidence for the mTOR inhibitor sirolimus as an effective treatment for specific vascular anomalies, its use remains 'off-label' and is not currently subsidised by the Australian government.This study aims to evaluate the cost-effectiveness of sirolimus as a treatment for vascular malformations from the Australian healthcare sector perspective.Methods: An exploratory cost-utility decision analysis was conducted from the Australian healthcare sector perspective.The simulated cohort consisted of Australian patients aged 18 years with slow flow vascular malformations requiring treatment.Patients were either initiated on sirolimus 1 mg daily or received supportive care.Health state utility values were derived from published literature.Cost data were sourced from hospital pharmacies and public reimbursement schedules.The primary outcomes measured were the changes in cost and quality-adjusted life-years (QALYs), and the incremental cost-effectiveness ratio (ICER).To account for uncertainties in parameter inputs, oneway and probabilistic sensitivity analyses were performed.Modelling and statistical analyses were performed using TreeAge Pro Healthcare, version 2024 R1.0.Results: Over a one-year time horizon, sirolimus treatment was associated with an increased expenditure of A$2833 and a gain of 0.08 QALYs when compared with supportive care, resulting in an incremental cost-effectiveness ratio of A$35,410/QALY.The one-way sensitivity analysis indicated that the ICER was sensitive to both utility input parameters and the cost of sirolimus medication.The probabilistic sensitivity analyses indicated 1 mg daily sirolimus was more cost-effective compared with supportive care in 55.1% of the 10,000 iterations of the Monte Carlo simulation.Across a threshold range of A$0-100,000/QALY, sirolimus was considered cost-effective in most iterations above a threshold of approximately A$34,000/QALY. Conclusions:At a standard willingness-to-pay threshold of A$50,000/QALY, our preliminary results suggest that sirolimus shows promise as a cost-effective therapeutic option for vascular malformations in an Australian healthcare setting.