Direct Preparation of Site‐Specific ADCs with Unpurified Antibodies in Culture Medium

In comparison with traditional chemotherapeutic drugs, antibody‐drug conjugates (ADCs) have been extensively employed in the management of numerous cancers due to their high selectivity and low systemic toxicity. However, the complexity of the ADC structure makes its preparation process more intricate and time‐consuming. The preparation of ADCs typically involves a multi‐step purification process, which increases the cost of ADC preparation considerably. Herein, we proposed an approach for the direct preparation of site‐specific ADCs in an antibody expression system that is derived from the reported K248 site‐specific modification technology. This strategy requires only one purification step to obtain site‐specific ADCs, thereby greatly shortening the preparation cycle of ADCs. We successfully achieved the preparation of site‐specific ADCs in the expression system of Sacituzumab. The resulting ADCs exhibited comparable physicochemical properties and activities to those obtained through the conventional two‐step purification strategy. It also demonstrates high compatibility to various linker and antibody. This strategy provides a succinct methodology for the preparation of site‐specific ADCs.