1306P - Cardiotoxic and pro-inflammatory effects induced by the association of immune checkpoint inhibitor pembrolizumab and trastuzumab in preclinical models

Abstract

BackgroundRecently, the world of oncology has been revolutionized by immunotherapy which has shown considerable advantages in terms of overall survival in cancer patients. The association of Pembrolizumab and Trastuzumab was recently proposed in clinical trials for the treatment of Trastuzumab-resistant advanced HER2-positive breast cancer. Although immunotherapies are frequently associated with a wide spectrum of immune-related adverse events, the cardiactoxicity has not been properly studied. MethodsIn human fetal cardiomyocytes exposed to Trastuzumab and Pembrolizumab alone or in combination, we studied: the cell viability (through MTS assay), the quantification of intracellular calcium, Interleukin 1β, 6 and 8; the expression of NF-kB and Leukotrienes. Preclinical studies were also performed in C57BL6 mice dividing them in 4 groups (6/group: untreated mice (control) ; mice treated with Pembrolizumab at 10mg/Kg for the first dose, followed by 5mg/Kg dose every 5 days until the study end point, according to literature; mice treated with Trastuzumab at 10mg/kg/day; mice treated with both drugs in combination. After the administration period, we analyzed the fibrosis and inflammation in heart tissues. ResultsThe combination of Pembrolizumab and Trastuzumab increases the intracellular calcium overload (of 3 times compared to untreated cells) and reduces the cardiomyocytes viability (of 65 and 20-25%, compared to untreated and Pembrolizumab or Trastuzumab treated cells, respectively; p<0.01 for both). Combination therapy increases the inflammation of cardiomyocytes by enhancing the expression of NF-kB and Interleukins. Moreover, in preclinical models, the association of Pembrolizumab and Trastuzumab increases the cardiac fibrosis and Interleukins expression of 40-50 % compared to the single treatments; the expression of NF-kB and Leukotriene B4 were also significantly increased, compared to the single treatments. ConclusionsThe association of Pembrolizumab and Trastuzumab exerts pro-inflammatory and pro fibrotic effects in the heart; these effects are mainly mediated by overexpression of NF-kB and Leukotriene B4 related pathways and pro-inflamamtory cytokines. Legal entity responsible for the studyThe authors. FundingThis work was funded by the “Ricerca Corrente” grant from the Italian Ministry of Health. DisclosureAll authors have declared no conflicts of interest.