A first study was conducted in primary leukaemia cells from CLL patients to evaluate the efficacy of various combination therapies, in which CX-4945 administration was combined with three different drugs: fludarabine, a purine analogue inhibitor of DNA synthesis, GS-1101 (idelalisib), a phosphoinositide 3-kinase p110ẟ (PI3Kẟ) inhibitor, or ibrutinib, a potent and irreversible inhibitor of Burton’s tyrosine kinase (BTK) [46]. Here, BTK is linked to B-cell chronic lymphocytic leukemia.