SHP-77 cells were grown in RPMI-1640 medium supplemented with 10% FBS and 1 ug/mL puromycin at 37 °C in a 5% CO2 incubator. SHP-77 cells were dissociated using TrypLETM Express Enzyme (Thermo Fisher Scientific, Waltham, MA, USA) and, after counting, the cells were resuspended in RPMI-1640 medium supplemented with 10% FBS at a density of 3 × 104 cells/mL. The cells were plated in 96-well plates and incubated at 37 °C for 24 h. ADCs and payloads were diluted separately and added to the 96-well cell culture plates containing cells, followed by incubation in a 5% CO2 incubator for 5 days. A multifunctional microplate reader was used, and the absorbance was measured at 450 nm with a reference wavelength of 630 nm. The IC50 values were calculated using GraphPad Prism 10.1.2 software.