Radiolabeled trastuzumab scintigraphy was not valuable in predicting trastuzumab-related cardiotoxicity in metastatic breast cancer patients, but can identify HER2-positive tumors. Measurement of plasma NT-proBNP is promising regarding prediction of trastuzumab-related cardiotoxicity.

No abstract

In using DTPA as a chelator. In-DTPAtrastuzumab (labelling yield 92.372.3%, radiochemical purity 97.071.5%) is stable in PBS when stored at 41C for more than 14 days. The immunoreactive fraction determined by cell-binding assays, using the HER2-overexpressing human ovarian SK-OV-3 tumour cell line, was 0.8770.06. Biodistribution and tumour targeting were studied in HER2 receptor-positive and -negative tumour-bearing athymic mice. The HER2-positive tumour showed (9.7771.14% injected dose per gram (ID g À1 )) substantial uptake of the labelled antibody already after 5 h. The difference in uptake between HER2-positive versus -negative tumours was even more pronounced 3 days after injection (16.3070.64% ID g À1 ), and was visualised by radioimmunoscintigraphy. Liver, spleen and kidney showed marked tracer uptake. In summary, trastuzumab can be efficiently radiolabelled with 111 In with high labelling yields and high stability. In-DTPA-trastuzumab selectively binds to the human HER2 receptor both in vitro and in vivo in animals. Therefore, 111 In-DTPA-trastuzumab appears suitable for clinical use.