64Cu-SAR-Bombesin PET-CT imaging in the staging of ER+/PR+/HER2- metastatic breast cancer: Safety, dosimetry, and feasibility in a phase I trial.

• DOI: 10.1200/jco.2022.40.16_suppl.3092
• Publication Date: 2022-06-06T16:07:54Z
• Authors: Keith Wong; Gemma Sheehan-Dare; Andrew Nguyen; Bao Ho; Victor Liu; Jonathan Lee; Lauren Julia Brown; Rachel Fitz-Geral...; Lyn Chan; Sarennya Pathmana...; Shikha Sharma; Alessandra Malaroda; Isabelle Smith; Elgene Lim; Louise Emmett
• Keywords: 03 medical and health sciences; 0302 clinical medicine; 3. Good health

3092 Background: Breast cancers are most frequently oestrogen receptor (ER) and progesterone (PR) positive 18 F-Fluorodeoxyglucose PET-CT (FDG) used in conventional staging of breast cancer has lower sensitivity for these subtypes. Gastrin releasing peptide receptors (GRPR) a potential alternative diagnostic theranostic target ER+/PR+ due to their overexpression GRPR. This phase 1 study aims assess the safety novel radiotracer 64 Cu-Sarcophagine(SAR)-Bombesin (BBN) re-staging recurrent metastatic ER+/PR+/human epidermal growth factor 2 negative (HER2-) cancer. Methods: Patients with confirmed or primary ER+/PR+/HER2- undergoing prior new treatment underwent Cu-SAR-BBN imaging at 1, 3 24 hours post-injection. Bloods vital signs were acquired patients baseline, post-injection timepoints, electrocardiogram (ECG) performed hour pre post injection. Blood tracer-clearance dosimetry was performed. GRPR status assessed 4/7 from metastatic-site biopsy samples. Staging by (FDG, bone scan CT) within weeks imaging. All PET scans visually, quantitatively using MIM Software. Results: 9 enrolled. 7/9 all modalities, while 2/9 did not undergo BBN 1/7 patient who had de- novo ER+/PR+/Her 2- 6/7 disease. 2/7 lobular subtype. There no adverse events reported, ECG, vitals haematological, biochemical coagulation markers remained unchanged. 7 on imaging, FDG. 5/7 patients. Both disease identified Conversely, but FDG negative. positive. In 4 patients, mean SUVmax higher than (15 vs. 12). classical subtype (2/7), highly avid compared (SUV max 20 vs 11, <3) tumor volume (2034 504, 634 mL negative). Conclusions: Cu-SAR-Bombesin is tracer which appears safe may have role cancer, particularly Further evaluation warranted.