To address this challenge, Motea et al developed the nucleoside analogue 5-nitroindolyl-2′-deoxynucleoside triphosphate (5-NITP, Figure 1) that is selectively utilised by TdT resulting in cytostatic and cytotoxic effects against leukaemia cells overexpressing TdT24,.25 Here, DNTT is linked to leukemia.