Cardiac function in patients receiving dual anti-Her2 antibodies (trastuzumab and pertuzumab) combined with chemotherapy for breast cancer in routine practice.

Abstract

e13009 Background: Chemotherapy regimens (C) containing a combination of anti-Her2 antibodies are associated with a risk of cardiac toxicity in landmark clinical trials. We evaluate the cardiac function of patients with Her2 over-expressed (Her2OE) breast cancer (BC) receiving C combined with trastuzumab (T) and pertuzumab (P) in routine clinical practice setting. Methods: The initial cohort of patients who started C in combination with TP (CTP) in standard doses and schedules before September 2019 in 4 cancer units were included. All patients had regular measurement of left ventricular ejection fraction (LVEF) by Doppler ultrasound studies. Data was collected retrospectively and was limited to the first 24 months after initiation of CTP treatment. The paired sample T-test was used to test the significance of the difference in LVEF. Results: Sixty seven patients were identified. CTP treatment was administered in the neoadjuvant and palliative settings in 28 (41.8%) and 39 (58.2%) respectively. None of the patients received concomitant anthracycline with TP. All patients underwent LVEF assessment prior to starting CTP treatment and at 3 and 6 months later. Subsequently LVEF was measured at 9, 12, 15, 18, 21 and 24 months as long as patients are still receiving CTP treatment (table). LVEF was measured in 11 patients for 24 months. Compared to baseline, mean LVEF was not significantly different at any of the subsequent time points (range; decrease by -0.936% to increase by 1.087%) (Table). Dual anti-Her2 antibodies (TP) administration was omitted temporarily once for 2 patients due to clinically suspected cardiac toxicity which was excluded on further investigations. Conclusions: In this cohort describing our limited initial experience, dual anti-Her2 antibodies (T&P) combined with chemotherapy is not associated with significant cardiac toxicity when LVEF is measured every 3 months. Further studies investigating less frequent LVEF monitoring (e.g. every 5-6 months) may be warranted.[Table: see text]