Peripheral endothelial function changes during HER2-directed therapy differ based on whether or not a patient receives anthracycline.

Abstract

1044 Background: Trastuzumab is well-demonstrated to be associated with cardiotoxicity (typically reduced ejection fraction), most commonly in patients who also receive anthracycline. The vascular effects of trastuzumab and anthracycline are understudied; we aimed to compare change in endothelial function during and after trastuzumab and to assess how anthracycline receipt affects this. Methods: This is an observational prospective study of women with newly diagnosed HER2-positive breast cancer. All participants underwent baseline evaluation of endothelial function testing by use of the EndoPAT2000 device approximately every three months over the subsequent 18 months after the initiation of HER2-directed therapy +/- anthracycline. The primary endpoint was change in endothelial function over time using the reactive hyperemia index (RHI). Framingham Risk Score (FRS) and lower RHI are both known to be independent predictors of future cardiovascular events in the general population. RHI deterioration was defined as a 20% reduction from baseline RHI to any available follow-up RHI assessment. Univariate analyses assessed if age, FRS, baseline RHI, and RHI deterioration differed between recipients and non-recipients of anthracycline using the Wilcoxon test. A multivariate logistic model evaluated FRS, age, and anthracycline receipt as possible independent predictors of RHI deterioration. Results: Among 38 eligible patients who consented and completed baseline assessments in addition to at least one follow-up assessment, 17 (45%) subsequently received anthracycline. 145 total follow-up RHI assessments were available overall (5 per patient on average). There were no differences between recipients and non-recipients of anthracyclines with regard to age [mean 49 years (SD 12) vs 53 years (SD 11); p=0.25], baseline FRS [mean 1.0 (SD 1.0) vs 1.5 (SD 1.4); p= 0.28] or baseline RHI [mean 2.4 (SD 0.6) vs 2.1 (SD 0.7); p=0.09]. RHI deterioration was more common for anthracycline recipients (mean 43% vs 21%; p=0.004), and in the multivariate model, anthracycline use was the only independent predictor of RHI deterioration (odds ratio: 2.8; 95% confidence interval: 1.35-6.07; p=0.006). Conclusions: This study suggests that endothelial dysfunction is more common after combined anthracycline and HER2-directed therapy than after HER2-directed therapy alone. RHI should be further studied as a possible early biomarker of cardiovascular toxicity in patients receiving treatment for breast cancer.