TST013 is a next generation ADC targeting LIV-1, a clinically validated tumor antigen, LIV-1 is highly expressed in breast cancer and other solid tumors. The ADC molecule combines the site-specific conjugation of TOPO-I inhibitor, with an in house humanized antibody which has distinct epitope and prolonged PK. We have obtained exciting anti-tumor activity data in in vivo pharmacology study for the ADC lead molecules. Compared with the benchmark ADC, TST013 displayed significantly improved anti-tumor activity with a good tolerability profile at clinically relevant doses.
• In December 2024, we presented a late-breaking poster for the preclinical data of TST013 at the San Antonio Breast Cancer Symposia (SABCS) 2024, titled “Novel Humanized LIV-1 Antibody Based ADCs Site-Specifically Conjugated with Topoisomerase I Inhibitor Payloads Displayed Significantly Higher Anti-tumor Activities than MMAE Based ADCs in TNBC Tumor Models”. The lead LIV-1 ADCs (ADC-1 and ADC-2) were engineered using the Company’s proprietary antibody with site-specific conjugation of Topoisomerase I (Topo I) inhibitor payloads. These ADCs demonstrated significantly higher tumor regression activities than MMAE based ADCs in TNBC tumor models. The significantly enhanced anti-tumor activities of ADC-1 and ADC-2 are likely due to the high binding affinity and high internalization efficiency of our proprietary antibody to LIV-1 and the high cytotoxicity of Topo I inhibitor for cancer cells. These data warrant further investigation of the lead LIV-1 targeting ADCs (ADC-1 and ADC-2) as potential next-generation therapeutic agents in LIV-1 expressing breast cancer and other solid tumors.
