Idelalisib-related pneumonitis

Idelalisib (Zydelig; Gilead Sciences Inc., Foster City, CA, USA) has recently been approved in combination with rituximab for the treatment of refractory chronic lymphocytic leukaemia (CLL) in patients who have received at least one prior therapy, as a first-line treatment in the presence of a 17p deletion or TP53 mutation in patients unsuitable for chemoimmunotherapy, or as a monotherapy in follicular lymphoma refractory to two prior lines of treatment. Idelalisib specifically inhibits phosphatidylinositol 3-kinase δ (PI3Kδ), which is part of the B-cell receptor signalling pathway, the activity of which is increased in B-cell malignancies, and which promotes cellular proliferation and survival [1–4]. Here, we report on five patients who were diagnosed with pneumonitis related to idelalisib treatment. Lung physicians and haematologists should be aware of the possibility of idelalisib-related lung manifestations