Topical Sirolimus 0.2% Gel for Facial Angiofibroma Associated with Tuberous Sclerosis Complex in the United States: A Cost-Effectiveness Analysis

OBJECTIVES: Topical sirolimus gel 0.2% is the first Food and Drug Administration (FDA) approved treatment for facial angiofibroma (FA) associated with tuberous sclerosis complex (TSC). A cost-effectiveness analysis was conducted comparing topical sirolimus 0.2% to best supportive care (BSC) for management of FA associated with TSC from a US third-party perspective.

METHODS: A semi-Markov model was developed based on patient characteristics obtained from Phase III and long-term (52-week) studies of topical sirolimus gel 0.2%. Investigator assessed composite improvement from baseline in size and redness of FA was used for efficacy inputs (Wataya-Kaneda et. al., 2018). The wholesale acquisition cost (WAC) of topical sirolimus gel was assumed to be $1,750. Healthcare costs were derived from a US claims database. Mortality risk associated with TSC was considered from published literature. Health-related quality of life (HRQoL) weights were obtained from a published study that fitted a mixed-effect model to map SF-36 to EQ-5D scores. Costs (2021 USD) and benefits were discounted at 3% annually. Incremental cost-effectiveness ratios (ICER) were estimated over a life-time horizon with a model cycle length of 13 weeks. Sensitivity analysis and scenario analysis were conducted across various parameters.

RESULTS: In the base case, on topical sirolimus gel 0.2%, the total cost was lower, and the total quality adjusted life years (QALYs) were higher than that of BSC. Thus, the ICER (i.e. cost per QALY gained) was ‘more effective and less costly’ for topical sirolimus gel 0.2% compared to BSC. The WAC for topical sirolimus gel 0.2%, was ~47%, ~50%, and ~53% below the price to exceed the willingness to pay (WTP) thresholds at $150,000, $100,000, and $50,000 per QALY gained. Results were considered robust to sensitivity and scenario analysis across various parameters.

CONCLUSIONS: Topical sirolimus gel 0.2% is cost-effective compared to BSC for patients with FA associated with TSC in the US.