Managing Patients With TP53-Deficient Chronic Lymphocytic Leukemia

Patients with chronic lymphocytic leukemia (CLL) having a chromosomal loss on the short arm of chromosome 17 including the TP53 gene locus (17p deletion) and/or having mutations in TP53 have a short overall survival and, until recently, limited treatment options. The recent introduction of two novel substance classes, B-cell receptor inhibitors and BH3 mimetics, into CLL treatment has provided enormous clinical progress in this previously difficult-to-treat patient subgroup characterized by high risk for treatment failure with standard chemoimmunotherapy and rapid disease progression. Compounds now approved for the treatment of TP53-deficient CLL are the two B-cell receptor inhibitors ibrutinib and idelalisib and the BH3 mimetic venetoclax. All three compounds were approved on the basis of favorable response rates that, importantly, revealed no differences between TP53-competent and TP53-deficient CLL cases. Using these compounds, longer-lasting remissions in patients with TP53-deficient CLL could be demonstrated for the first time. Whether TP53 alterations will maintain their significance as adverse prognostic factors in treatment strategies involving novel compounds needs to be assessed. This review provides an overview of current treatment options for 17p-deleted/ TP53-mutated CLL, including those compounds that are already approved by the US Food and Drug Administration or are under advanced clinical investigation. Available clinical trial data are discussed, as is the use of novel targeted treatment options in the context of transplant strategies, and an algorithm for off-study treatment of 17p-deficient CLL is suggested.