Cost-Effectiveness Analysis of Adjuvant Pertuzumab and Trastuzumab in Human Epidermal Growth Factor Receptor 2-Positive Early Breast Cancer in Japan

Human epidermal growth factor receptor 2 (HER2)-positive breast cancer presents considerable treatment challenges owing to its aggressive nature. Global guidelines have endorsed a full year of HER2-targeted therapy for early-stage breast cancer. However, previous cost-effectiveness analyses of dual HER2-targeted therapies have been limited. This study aimed to examine the cost effectiveness of dual HER2-targeted therapy for early-stage breast cancer within the Japanese healthcare system context. In the Markov model-based study, the cost effectiveness of dual anti-HER2 therapy, combining pertuzumab and trastuzumab, was assessed in comparison to trastuzumab monotherapy. Patients in whom treatment was initiated at a median age of 51 years were included. The study utilized quality-adjusted life years (QALYs) and incremental cost-effectiveness ratios (ICERs) as comparison units. Subgroup analyses were conducted to explore variations in cost effectiveness, focusing on node-positive and node-negative patients. Both one-way deterministic and broader probabilistic sensitivity analyses using Monte Carlo simulations with 10,000 samples were performed from the Japanese healthcare payers perspective. Dual HER2-targeted therapy led to 0.17 QALYs increment at an additional cost of $US15,289, resulting in an ICER of $US92,232 per QALY. In the subgroup of node-positive patients, the benefit of the dual HER2-targeted therapy was more pronounced, with an increase of 0.64 QALYs and an ICER of $US24,561 per QALY. Sensitivity analyses revealed the model's susceptibility to changes in the transition probabilities from invasive disease-free survival to death, from invasive disease-free survival to first-line metastatic breast cancer, and to costs associated with pertuzumab. Probabilistic sensitivity analysis suggests that for node-positive patients, dual HER2-targeted therapy may be a cost-effective option. The economic viability of dual HER2-targeted therapy was most pronounced in patients with node-positive high-risk early breast cancer. This study highlights the potential of dual HER2-targeted therapy as a cost-effective addition for these cases.