The Next Generation of Targeted Molecules for the Treatment of Chronic Lymphocytic Leukemia.

With the recent approval of several new targeted therapies for chronic lymphocytic leukemia (CLL), there are now multiple options for its treatment. Inhibitors of Bruton tyrosine kinase (with ibrutinib being the first-in-class US Food and Drug Administration-approved agent) and phosphoinositide 3-kinase (with idelalisib as the first-in-class approved agent) are promising because they are generally well tolerated and highly effective against this malignancy. These agents may be particularly important in the treatment of older patients who are less able to tolerate the myelosuppression (and subsequent infections) associated with chemoimmunotherapy. As a class of medications, B-cell receptor inhibitors have some unique side effects, including redistribution lymphocytosis. Toxicities associated specifically with ibrutinib include increased risk for bleeding and atrial fibrillation. Idelalisib also has some unique toxicities: transaminitis, colitis, and pneumonitis. Targeted therapies recently approved for use in CLL include the novel anti-CD20 monoclonal antibodies obinutuzumab and ofatumumab, and the B-cell lymphoma 2 inhibitor venetoclax. This article describes the clinical data that led to approval of these B-cell receptor inhibitors for the treatment of CLL, and highlights newer agents in clinical development that target the same kinases as the currently available therapies.