DM1-(PEG)4-DBCO is a drug-linker conjugate that combines the potent microtubulin inhibitor mertansine (DM1) with the DBCO-PEG4-Ahx linker for the development of antibody-drug conjugates (ADCs). This conjugation aims to mitigate the systemic toxicity associated with maytansine while improving tumor-specific delivery, leveraging DM1’s capabilities as an antibody-conjugatable maytansinoid.