4-(3-Tosyl-2-(tosylmethyl)propanoyl)benzoic acid-glu(PEG24-Me)-val-cit-NH-benzyloxyformic acid-MMAE is a component of a drug-linker conjugate for ADC. It includes a linker and a biologically active small molecule toxin, MMAE. This compound can conjugate with NN2101 (anti-c-Kit) to form NN3201, which rapidly internalizes and inhibits SCF-driven signal transduction, inducing cell cycle arrest and apoptosis through payload delivery. NN3201 exhibits significant c-Kit-dependent antitumor activity in various tumor models, such as small cell lung cancer (SCLC) and gastrointestinal stromal tumors (GIST).