This competitive inhibition resulted in nanomolar cytotoxicity in leukaemia cells.14 Further SAR studies showed that compound 13 (Fig. 1d) caused a high level of inhibition of RelA/p65-DNA binding in chronic lymphocytic leukaemia (CLL) cells.12,14 Other molecules, like CRL1101 and IT-901 (Fig. 1e and f), were also reported to block NF-κB subunits RelA/p65 and c-Rel8,15 but none of these compounds have been approved for use as anticancer agents. Here, RELA is linked to B-cell chronic lymphocytic leukemia.