Cell-selective targeting of ADC-2 and ADC-3 was then tested in a HEK293 HER2-cell line using a HiBiT assay. Both ADC-2 and ADC-3 exhibited RIPK2 degradation at higher concentrations, with a more prominent effect as the concentration exceeded 100 nM. This agrees with the similar degradation observed in SKOV3 cells is likely due to non-specific uptake. Most importantly, no degradation was observed at 10 nM for both conjugates compared to 50% degradation when PROTAC 1 was used (Figure ). Again, no cytotoxicity was observed for all compounds (Figure ). In summary, we have demonstrated cell-selective degradation of RIPK2 in HER2+ and SKOV3 cells using an Ab-PROTAC conjugate. This approach complements ADC developments and provides a design strategy to use PROTACs which have sub-optimal physicochemical properties or where cell selective delivery of the PROTAC payload is required.