OBJECTIVES: To estimate the potential impact on US third-party payers’ (commercial or Medicare) formulary budgets of introducing selpercatinib for rearranged during transfection (RET)-altered solid tumor treatment.

METHODS: A budget impact model with 3-year time horizon was developed for nineteen different RET-altered tumors, with customizability to conduct user-preferred analyses integrated across all or scenario-specific selected tumors. Eligible patient populations were estimated from US epidemiological statistics. Tumor-specific comparator treatment representative of each disease was included across all tumors. All FDA-approved RET inhibitors were included for their respective indications. Annual total costs (2022 USD) included costs of drug, administration, supportive care, and toxicity. For a hypothetical one-million-member plan, number of treatment-eligible and selpercatinib-treated patients with RET-altered tumors, and incremental per-member per-month (PMPM) costs of introducing selpercatinib were estimated. To avoid underestimation, the base-case model assumed that all patients received biomarker testing and were treatment-eligible. Uncertainty associated with model parameters and key assumptions were assessed using one-way sensitivity analyses (OWSA).

RESULTS: In the commercial perspective, an estimated 11.68 patients were treatment-eligible annually. Of these, based on the forecasted market share, 7.59 (year1), 8.17 (year2), and 8.76 (year3) patients were selpercatinib-treated. Their associated incremental PMPM costs were $0.073 (year1), $0.180 (year2), and $0.213 (year3). In the Medicare perspective, an estimated 55.82 patients were treatment-eligible annually. Of these, 36.29 (year1), 39.08 (year2), and 41.87 (year3) patients were selpercatinib-treated. Their associated incremental PMPM costs were $0.371 (year1), $0.923 (year2), and $1.053 (year3). Most OWSA across both perspectives identified drug costs, selpercatinib market share, incidence of RET, and treatment duration as significant drivers of incremental costs.

CONCLUSIONS: Three-year incremental PMPM estimates ranged from $0.073–$0.213 (commercial) and $0.371–$1.053 (Medicare), suggesting minimal impact on payer-budgets associated with the introduction of selpercatinib. These findings should be interpreted with caution given the uncertainty associated with several assumptions and parameters.