The RESONATE study (PCYC-1112) in relapsed/refractory CLL/SLL [86 % high-risk alterations (del17p/TP53 mutation), del(11q) and/or unmutated IGHV] showed significant improvements in PFS and OS with ibrutinib compared to anti-CD20 ofatumumab. This evidence concerns the gene TP53 and B-cell chronic lymphocytic leukemia.