Economic evaluation of SP142 IHC assay versus 22C3 IHC assay in patients with unresectable locally advanced or metastatic triple-negative breast cancer in the Brazilian private healthcare system.

Abstract

e13097 Background: The IMpassion130 trial has demonstrated that atezolizumab plus nab-paclitaxel results in significant clinical benefits for patients with unresectable locally advanced or metastatic (aTNBC). The SP142 IHC assay is a clinically validated and FDA-approved PD-L1 test to identify patients with aTNBC for treatment with atezolizumab plus nab-paclitaxel. A post hoc analysis of IMpassion130 evaluated two other PD-L1 IHC assays, 22C3 and SP263, for analytical and clinical concordance with SP142 and the PD-L1 prevalence by each assay. The prevalence of PD-L1+ per SP142 (tumor-infiltrating immune cells 1%), 22C3 (combined positive score1) and SP263 (tumor-infiltrating immune cells 1%), were 46%, 81% and 75%, respectively. The study compared only SP142 assay with 22C3 assay because patients with SP142 negative and 22C3 positive did not demonstrate a significant clinical benefit for progression-free survival (PFS) and overall survival (OS). Therefore the study aimed to demonstrate the economic impact of these assays in the treatment with atezolizumab plus nab-paclitaxel. Methods: Data of PFS and OS from the post hoc analysis of Impassion130 were extracted to develop a Markov model to simulate the clinical and economic impact of the patient with atezolizumab plus nab-paclitaxel guided by SP142 and 22C3 assays. The analysis considered the cost of atezolizumab+nab-paclitaxel, the cost associated with the management of the adverse events and the cost of the assay. The costs were based on CBHPM (Classificação Brasileira Hierarquizada de Procedimentos Médicos), CMED PF18% (Câmara de Regulação do Mercado de Medicamentos) and local publications. An univariate sensitivity analysis was performed. Results: The study demonstrated that SP142 assay has the potential to save 175,917 BRL (45,595 USD) with atezolizumab plus nab-paclitaxel per patients with aTNBC in three years. Conclusions: The SP142 assay can optimize the use of atezolizumab plus nab-paclitaxel avoiding its use in patient who will not have a significant clinical improvement.