Managing toxicities of phosphatidylinositol-3-kinase (PI3K) inhibitors

Despite the proven effective approach to targeting the phosphatidylinositol-3-kinase (PI3K) pathway in B-cell malignancies, the approved PI3K inhibitors idelalisib and duvelisib have been less commonly selected for patients with chronic lymphocytic leukemia/small lymphocytic lymphoma (CLL/SLL), given the availability of other more tolerable agents. However, patients with CLL/SLL can experience a disease course that is multiply relapsed, refractory, or intolerant to treatment, and PI3K inhibitors can achieve meaningful responses. This article reviews the common early- and late-onset (considered immune-mediated) toxicities with PI3K inhibitors, including infections, hepatotoxicity, diarrhea and/or colitis, and pneumonitis. Data on pretreatment considerations, toxicity management, and drug rechallenge are presented. In addition, next-generation PI3K inhibitors and novel treatment approaches with PI3K inhibitors, including combinations, time-limited treatments, and intermittent dosing, are highlighted.