Introduction: Phosphoinositide 3-kinase delta (PI3Kδ) inhibitors are a class of novel agents that are mainly used to treat B-cell malignancies. They function by inhibiting one or more enzymes which are part of the PI3K/AKT/mTOR pathway. Idelalisib is a first-in-class PI3Kδ inhibitor effective in patients with B-cell lymphoid malignancies.
Areas covered: This article reviews the chemical structure, mechanism of action, and metabolic and toxicological properties of PI3Kδ inhibitors and discusses their clinical applications in monotherapy and in combination with other agents for the treatment of chronic lymphocytic leukemia (CLL). A search was conducted of PubMed, Web of Science, and Google Scholar for articles in English.
Results/conclusion: PI3Kδ inhibitors hold potential for the treatment of B-cell malignancies, including CLL. However, their use is also associated with severe toxicities, including pneumonia, cytopenias, hepatitis, and rash. Newer drugs are in development to reduce toxicity with novel schedules and/or combinations.
Expert opinion: The development of novel PI3Kδ inhibitors might help to reduce toxicity and improve efficacy in patients with CLL and other B-cell lymphoid malignancies.
Keywords: B-cell neoplasms; chronic lymphocytic leukemia; copanlisib; duvelisib; idelalisib; parsaclisib; umbralisib; zandelisib.