301. (111)In-trastuzumab scintigraphy in HER2-positive metastatic breast cancer patients remains feasible during trastuzumab treatment.
- Author
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Gaykema SB, de Jong JR, Perik PJ, Brouwers AH, Schröder CP, Oude Munnink TH, Bongaerts AH, de Vries EG, and Lub-de Hooge MN
- Subjects
- Antibodies, Monoclonal, Humanized chemistry, Antibodies, Monoclonal, Humanized pharmacokinetics, Antibodies, Monoclonal, Humanized therapeutic use, Antineoplastic Agents administration & dosage, Antineoplastic Combined Chemotherapy Protocols, Drug Administration Schedule, Female, Humans, Neoplasm Metastasis diagnostic imaging, Neoplasm Metastasis drug therapy, Paclitaxel administration & dosage, Radionuclide Imaging, Receptor, ErbB-2 metabolism, Trastuzumab, Antibodies, Monoclonal, Humanized administration & dosage, Breast Neoplasms diagnostic imaging, Breast Neoplasms drug therapy, Indium Radioisotopes
- Abstract
Human epidermal growth factor receptor (HER)2 imaging with radiolabeled trastuzumab might support HER2-targeted therapy. It is, however, frequently questioned whether HER2 imaging is also possible during trastuzumab treatment as the receptor might be saturated. We studied the effect of trastuzumab treatment on 111In-trastuzumab uptake. Patients received trastuzumab weekly and paclitaxel once every 3 weeks. 111In-trastuzumab was injected on day 1 of cycle 1 and day 15 of cycle 4. Whole-body planar scintigraphy was acquired at different time points postinjection. Tumor uptake and organ distribution between the first and repeated scan series were calculated via residence times. Twenty-five tumor lesions in 12 patients were visualized on both scintigraphy series. Tumor uptake decreased (19.6%; p = .03). The residence times of normal organs remained similar except for the cardiac blood pool (+ 16.3%; p = .014). Trastuzumab treatment decreases tumor 111In-trastuzumab uptake around 20%. HER2 imaging is feasible during trastuzumab treatment.
- Published
- 2014
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