PDE4A and cancer: Additionally, although extensive development of IAP‐based SNIPER PROTACS against a range of proteins implicated in cancer, immune disease, and neurodegenerative diseases has followed since their initial discovery [37], the PDE4 SNIPER has not been taken forward, probably due to lack of potency, ‘flat’ dose–response curve and inefficient proteolysis of the PDE4 target which left over 40% of the starting protein intact at high nanomolar concentrations [36].