China-based biotech company Transcenta Holdings Ltd (HKG: 6628) announced updated results from a pre-clinical study for its LIV-1 antibody-based antibody drug conjugates (ADCs) at the 2024 San Antonio Breast Cancer Symposium (SABCS). The study focuses on the potential of LIV-1 as a therapeutic target in metastatic breast cancer.
LIV-1 as a Therapeutic Target and Transcenta’s 48D6 Antibody
LIV-1, a member of the zinc transporter family and an estrogen-regulated gene, is overexpressed in multiple malignant tumors, including metastatic breast cancer. Transcenta has generated a proprietary novel humanized anti-LIV-1 monoclonal antibody (mAb), 48D6. Pre-clinical in vivo pharmacology studies have revealed that ADC-1 and ADC-2, conjugates of 48D6 with Topoisomerase I Inhibitor payloads, exhibit dose-dependent and potent anti-tumor activities in human LIV-1 transfected MDA-MB-468, a triple-negative breast cancer (TNBC) tumor model.
ADC-1 and ADC-2 Demonstrate Superior Tumor Regression Activities
At a dosage of 3 mg/kg, the tumor growth inhibition (TGI) percentages on Day 30 were as follows: ADC-1 at 92.4%, ADC-2 at 94.7%, ADC-3 at 68.5%, and the SGN-LIV1A analog at 57.0%. Notably, the overall response rate (ORR, defined as a 50% reduction of tumor volume from baseline) at 3 mg/kg for the SGN-LIV1A analog and ADC-3 was 0%, while ORRs for ADC-1 and ADC-2 were 40% and 70%, respectively. At a higher dosage of 6 mg/kg on Day 42, ORRs for ADC-1 and ADC-2 were 90% and 100%, respectively, with complete response (CR) rates of 90% and 100%. Importantly, the body weight of mice did not significantly change at either dosage, indicating the well-tolerated nature of ADC-1 and ADC-2.
