Idelalisib is a first-in-class selective inhibitor of adenosine-5'-triphosphate (ATP) binding to PI3Kdelta kinase, resulting in inhibition of the P13K signalling pathway in malignant B cells. The compound is approved for the treatment of several types of blood cancer. Idelalisib is intended to be used in combination with rituximab as second or subsequent line therapy for the treatment of chronic lymphocytic leukaemia. The drug may cause fatal and/or severe diarrhea or colitis, hepatotoxicity, pneumonitis and intestinal perforation.

Copanlisib, developed by Bayer, is a phosphoinositide 3-kinase (PI3K) inhibitor with potential antineoplastic activity. Copanlisib inhibits the activation of the PI3K signaling pathway, which may result in inhibition of tumor cell growth and survival in susceptible tumor cell populations. Activation of the PI3K signaling pathway is frequently associated with tumorigenesis and dysregulated PI3K signaling may contribute to tumor resistance to a variety of antineoplastic agents. Copanlisib is currently under Phase II/III clinical trials for the treatment of non-Hodgkin lymphoma and chronic lymphocytic leukemia.