BACKGROUND: Neratinib, an oral, irreversible tyrosine kinase inhibitor of multiple HER receptors, is approved in combination with capecitabine ("neratinib") in the United States (US) for adults with HER2+ metastatic breast cancer (mBC) who have received ≥2 anti-HER2 therapies. Neratinib significantly improved progression-free survival versus lapatinib + capecitabine ("lapatinib") in clinical trials. There are several treatment options for this population with varying efficacies, adverse event (AE) profiles, and costs.
OBJECTIVE: To estimate the budget impact for US health care payers of adding neratinib to the currently available third-line anti-HER2+ treatments for mBC in the US.
METHODS: A budget-impact model was developed to compare health care payer costs for third-line treatment of HER2+ mBC over 5 years between treatment scenarios with and without neratinib for a hypothetical 1-million-person commercial plan of adults aged ≥18 years. The treatment options were neratinib, lapatinib, tucatinib + capecitabine + trastuzumab ("tucatinib"), and intravenous fam-trastuzumab deruxtecan-nxki ("DS-8201"). The population eligible for treatment was calculated from the published literature. Two market share scenarios were used: one with equal market shares and one with uptake based on clinical expert projections. Treatment duration, dosing, AE incidence, and monitoring requirements were obtained from key clinical trials and prescribing information. Costs for drug acquisition, unit monitoring, and AEs were obtained from wholesale acquisition costs, fee schedules, and the Healthcare Cost and Utilization Project. Total incremental and per-member-per-month (PMPM) costs were calculated in 2019 US dollars by comparing total health plan costs in the treatment scenarios with and without neratinib over 5 years.
RESULTS: In the first year, an estimated 66 patients would be eligible for third-line anti-HER2 treatment for mBC, with 33 incident patients becoming eligible each subsequent year. Average monthly costs per treated patient were $15,037, $9,283, $26,061, and $14,826 for neratinib, lapatinib, tucatinib, and DS-8201, respectively. The treatment scenario with neratinib reduced total annual health plan costs by $2.2 million ($0.04 PMPM) for equally distributed market shares and $890,299 ($0.01 PMPM) for clinical expert market shares over 5 years compared with the treatment scenario without neratinib.
CONCLUSIONS: The introduction of neratinib over 5 years could potentially reduce US health plan costs for treating HER2+ mBC by reducing use of more expensive regimens.
