Luo, Caili, Ren, Anni, Jin, Zixuan, Zhang, Jianxin, Shi, Wei, Zeng, Yue, Liu, Zhaojun, Lu, Mengru, Hou, Yajing, Tang, Feng, and Huang, Wei
[Display omitted] • Based on our previous work, site-specific ADCs targeting TROP2 were synthesized via IgG glycoengineering or affinity-directed traceless conjugation. These site-specific conjugation methods of modifying IgG Fc fragment were unique. • With improved homogeneity, hydrophilicity & stability, the one-step-made gsADC 3b showed superior in vitro & in vivo anti-tumor efficacy. • The reduced in vivo efficacy was observed in two-step site-specific gsADCs. One way to retain in vivo anti-tumor activity is by balancing the cyclooctyne-functionalized linker fragment with the hydrophilicity fragment mPEG 24 (gsADC 5b vs. gsADC 5d). The approval of Trodelvy® validates TROP2 as a druggable but challenging target for antibody-drug conjugates (ADCs) to treat metastatic triple-negative breast cancer (mTNBC). Here, based on the TROP2-targeted antibody sacituzumab, we designed and developed several site-specific ADC candidates, which employ MMAE (monomethyl auristatin E) as the toxin, via IgG glycoengineering or affinity-directed traceless conjugation. Systematic evaluation of these site-specific ADCs in homogeneity, hydrophilicity, stability, and antitumor efficiency was conducted. The results indicate that the site-specific ADCs gsADC 3b made from one-step glycoengineering exhibit good aggregation stability and in vivo efficacy, providing a new format of ADCs that target TROP2. [ABSTRACT FROM AUTHOR]