Xue-miao Tang, Hao Chen, Qing Li, Yiling Song, Shuping Zhang, Xiao-Shuan Xu, Yiwei Xu, Shulin Chen

The cardiac safety of cetuximab and panitumumab, particularly as single agents, has not been investigated extensively. This trial was designed to specifically evaluate the cardiac safety of cetuximab and panitumumab as single therapy in Chinese chemotherapy-refractory metastatic colorectal cancer (mCRC) patients. Sixty-one patients received cetuximab at an initial dose of 400 mg/m2 intravenously over 120 minutes on day 1 (week 1), followed by a maintenance dose of 250 mg/m2 intravenously over 60 minutes on day 1 of each 7-day cycle. Forty-three patients received panitumumab at a dose of 6 mg/kg intravenously every 14 days. Routine laboratory tests and electrocardiogram (ECG) were performed at baseline, during therapy and after the treatment (4th and 10th months). The incidence of elevation of troponin I ultra (TNI Ultra), abnormal ECGs, cardiac events and noncardiac adverse events (AEs) were recorded and analyzed. The incidence of elevation of TNI Ultra between the two groups had no significance (p=0.681), and TNI Ultra+ was observed more frequently in patients with metastases to more than three organs and they received fourth or above lines of chemotherapy. The most frequent abnormal ECG manifestations were nonspecific ST changes and QTc prolongation in the two groups. At 10 months after treatment, most of the abnormal ECG manifestations were reversed. The most common cardiac AEs of cetuximab and panitumumab included palpitations, dyspnea, chest pain and arrhythmias requiring treatment. Most of the events were mild and transient. The incidence of cardiac AEs had no significant difference between the two groups. Rash was still the most common noncardiac AE in both groups. Cetuximab and panitumumab showed favorable cardiac safety as single agents for Chinese chemotherapy-refractory mCRC patients. But monitoring for cardiac AEs is still necessary throughout the entire treatment process.