OBJECTIVES : Treatment options for HER-2-positive metastatic breast cancer (mBC) patients have expanded markedly since trastuzumab approval in 1998. Several other regimens are now available, including pertuzumab plus trastuzumab plus docetaxel, T-DM1, capecitabine plus lapatinib, and trastuzumab plus lapatinib. This study assesses the cost-effectiveness of four treatment sequences for HER-2-positive mBC according to the Taiwanese National Health Insurance Administration (TNHIA).

METHODS : Lifetime costs (U.S. Dollars) and effectiveness (quality-adjusted life years) of treatment decisions for HER-2-positive mBC patients were examined using a Markov model. Transition probabilities, disease progression, and the probability of adverse events and survival were derived from clinical trial data. Costs and health utilities were estimated from TNHIA, Taipei Medical University Hospital, and the literature. Deterministic, probabilistic sensitivity analyses and a scenario analysis examined parameter uncertainty and accounted for drug wastage in dosage and cost calculations.

RESULTS : Sequence 3 (1^st line: trastuzumab plus docetaxel; 2^nd line: T-DM1; 3^rd line: trastuzumab plus lapatinib) was the most cost-effective sequence followed by sequence 1 (1^st line: pertuzumab plus trastuzumab plus docetaxel; 2^nd line: T-DM1; 3^rd line: capecitabine plus lapatinib), and sequence 4 (1^st line: trastuzumab plus docetaxel; 2^nd line: trastuzumab plus lapatinib; 3^rd line: trastuzumab plus capecitabine), respectively. The model was sensitive to costs and transition probabilities, but not particularly sensitive to the wastage assumption.

CONCLUSIONS : From the perspective of the TNHIA, using trastuzumab plus docetaxel as 1^st line followed by T-DM1 and trastuzumab plus lapatinib as 2^nd and 3^rd line yields the most cost-effective strategy for treating HER-2-positive mBC patients.