Dynamic monitoring of antibody drug conjugates targeting TROP2 or HER2 in breast cancer using circulating tumor cells - PubMed
3 hours ago
- #circulating tumor cells
- #antibody-drug conjugate
- #breast cancer
- Antibody-drug conjugates (ADCs) targeting TROP2 or HER2 are effective in metastatic breast cancer, but tumor biopsy expression levels don't strongly correlate with response.
- Serial imaging of circulating tumor cells (CTCs) in 35 patients showed highly heterogeneous TROP2 and HER2 expression in both CTCs and biopsies.
- Pre-treatment epitope levels on CTCs do not predict clinical response, but absence or >80% reduction in CTCs after three weeks predicts durable response.
- Targeted epitopes are not downregulated at acquired resistance, and switching between TROP2- and HER2-targeting ADCs rarely leads to second-line response.
- CTCs serve as a dynamic surrogate for tumor burden, and sensitivity to the drug payload may drive response to ADCs in breast cancer.