Targeted PI3Kδ inhibition by the small molecule idelalisib as a novel therapy in indolent non-Hodgkin lymphoma.

Indolent Non-Hodgkin Lymphomas (iNHL) are typically B-cell malignancies and are incurable with current standard approaches. Thus, there is a demand for novel agents specific for this group of disorders. In a phase II study published by Gopal et al. in the New England Journal of Medicine, idelalisib, a small molecule inhibitor of PI3Kδ that was FDA approved in July of 2014, was shown to be effective when combined with rituximab in patients who cannot tolerate chemotherapy and as last line therapy in patients with iNHL refractory to 2 prior systemic therapies. Idelalisib demonstrated tolerable diarrhea, fatigue, nausea, pyrexia, and cough. While this novel agent is a clinically significant addition to the iNHL arsenal, further research is needed to determine its most appropriate place in iNHL therapy.