Current status of phosphoinotiside-3 kinase inhibitors in blood cancers.

PURPOSE OF REVIEW: Treatment of non-Hodgkin lymphoma (NHL) and chronic lymphocytic leukemia (CLL) underwent paradigm shifts, with targeted agents rapidly displacing chemotherapy. Phosphoinotiside-3 kinase (PI3K) is essential for survival and proliferation of neoplastic B cells and has proven a tractable target in NHL, with four agents receiving FDA approval in the last decade. This review summarizes key data and challenges associated with use of PI3K inhibitors in routine practice.

RECENT FINDINGS: Idelalisib and duvelisib are active in CLL and indolent NHL, including in patients with high-risk features. Despite differential targeting of PI3K isoforms, they exhibit comparable efficacy and adverse event profile including autoimmune events (transaminitis, colitis, pneumonitis), mediated by Treg/Th17 imbalance. Although copanlisib, a pan-PI3K inhibitor, is associated with a distinct safety profile (hyperglycemia, hypertension), preclinical studies indicate that umbralisib, a dual inhibitor of PI3Kδ and casein kinase 1ε, may have less effect on Tregs. However, both drugs may still cause immune-mediated toxicities.

SUMMARY: With close monitoring and management of adverse events, PI3K inhibitors continue to have a role in therapy of R/R CLL and NHL. Strategies to mitigate adverse events and increase efficacy of PI3K inhibitors include time-limited combination approaches, intermittent dosing schedules.