OBJECTIVES : Breast cancer is the most common cancer in women in Brazil. In an advanced stage it is considered an incurable disease, but the development of systemic treatment, especially innovative medicines, such as CDKs 4/6 inhibitors has provided increased survival and quality of life for patients with HR+ / HER2- advanced or metastatic breast cancer when compared with hormonotherapy alone. The aim of this analysis is to compare effectiveness and costs between palbociclib + letrozole versus letrozole alone in the treatment of metastatic breast cancer HR+ / HER2- in post-menopausal women in first line.

METHODS : A partitioned cost-effectiveness model was developed in the perspective of the Brazilian public healthcare system (SUS), through a lifetime horizon. A recent real-world evidence (RWE) study made with the Flatiron retrospective database analysis of 1,430 women in the US was utilized to populate the model with effectiveness data. Only direct costs associated with pre-progression, progression, post-progression and management of adverse events were considered.

RESULTS : By utilizing the effectiveness data from the Flatiron RWE study and by including all local direct costs in the model, it was possible to estimate that palbociclib + letrozole is an alternative treatment with greater effectiveness at a higher cost when compared with letrozole alone, presenting an ICER of: BRL 441,033 for LY gained; BRL 825,897 per year gained with no progression and BRL 726,906 per QALY.

CONCLUSIONS : RWE has been increasingly used in cost-effectiveness models around the world. In the presented case of palbociclib, these data have confirmed that palbociclib plus letrozole is more effective than letrozole alone in patients with advanced or metastatic breast cancer HR+ / HER2-. Despite the need of an incremental investment, palbociclib provides meaningful gains for patients and the healthcare system.