Economic evaluation of sequencing strategies in HER2-positive metastatic breast cancer in Mexico: a contrast between public and private payer perspectives.

Purpose: Breast cancer is the most common malignancy among women in Mexico. A large proportion of Mexican patients present with advanced disease, and 25% have HER2-positive tumors. We performed a cost-effectiveness analysis of different sequencing strategies of HER2-targeted agents in Mexico according to various payer perspectives.
Methods: A Markov model was constructed to evaluate the cost-effectiveness of four different HER2-targeted treatment sequences among patients with HER2-positive metastatic breast cancer treated in Mexico according to three public and one private payer perspectives. Patients were followed weekly over their remaining life expectancies within the model. Health states considered were progression-free survival (PFS) 1st-3rd lines, and death. Transition probabilities between states were based on published trials. Cost data were obtained from official publications from Mexican healthcare institutions. The evaluated outcomes were PFS, OS, costs, QALYs, and incremental cost effectiveness ratio (ICER).
Results: In the public payer perspective, sequences containing pertuzumab or T-DM1 were not cost-effective when compared with a sequence including the combination of trastuzumab/docetaxel as first line without subsequent T-DM1 or pertuzumab, even when utilizing alternate definitions for willingness to pay thresholds. In the private payer perspective, a sequence containing T-DM1 but not pertuzumab proved cost-effective at a lower clinical effectiveness.
Conclusions: In Mexico, the use of at least three lines of trastuzumab in combination with other therapies, but not with pertuzumab or TDM-1, represents the most cost-effective option for patients covered by the public healthcare system, and this sequence should be made available for all patients.