OBJECTIVES: Trastuzumab has significantly enhanced the survival and prognosis of individuals diagnosed with human epidermal growth factor receptor 2 (HER2)-positive early breast cancer. Considering its high costs, we aimed to examine the cost-effectiveness of trastuzumab plus chemotherapy compared with chemotherapy alone in Indonesia from healthcare payer perspective.

METHODS: A Markov model was developed to estimate the cost-effectiveness over a lifetime horizon for a cohort of women with HER2-positive early breast cancer. The analysis compared 12 months of trastuzumab plus chemotherapy versus chemotherapy alone. Efficacy data and baseline characteristics in the base-case analysis were primarily derived from the 11-year results of the HERA trial. Costs were based on verified BPJS Kesehatan reimbursement data from 2020. To assess the influence of parameter uncertainty, sensitivity analyses were conducted. Additionally, scenario analysis was carried out based on the joint analysis from NSABP B-31 and NCCTG N9831, which allowed us to conduct subgroup analysis based on age at diagnosis.

RESULTS: The base case results, using a lifetime horizon, showed total discounted costs for trastuzumab plus chemotherapy, and chemotherapy alone of US$33,744 and US$22,720 respectively, with savings of US$11,024. The total lifetime quality-adjusted life years (QALYs) for trastuzumab plus chemotherapy and chemotherapy regimen were 8.10 and 6.48, respectively, resulting in an incremental QALY gain of 1.61. The incremental life years gain (LYG) for trastuzumab was 2.00. This resulted in ICERs of US$6,842 per QALY and US$5,510 per LYG. In scenario analysis, the subgroup with age at diagnosis <40 years old was the most cost-effective option. The base-case and scenario analyses all showed ICERs far below the willingness to pay threshold. Sensitivity analyses confirmed the robustness of the findings and conclusion.

CONCLUSIONS: In Indonesia, trastuzumab plus chemotherapy is cost-effective compared to standard chemotherapy alone, and is potentially most cost-effective in the age group <40 years of age.