Idelalisib: a review of its use in chronic lymphocytic leukaemia and indolent non-Hodgkin's lymphoma.

Idelalisib (Zydelig®) is a first-in-class, orally administered, phosphatidylinositol 3-kinase-δ inhibitor that was recently approved for the treatment of relapsed chronic lymphocytic leukaemia (CLL), relapsed follicular B-cell non-Hodgkin's lymphoma (NHL) and relapsed small lymphocytic lymphoma (SLL) in the USA and for the treatment of CLL and refractory follicular lymphoma in the EU. In a pivotal phase III trial in patients with relapsed CLL who were not able to receive cytotoxic agents, recipients of idelalisib plus rituximab had significantly improved progression-free survival, overall survival, overall response and lymph node response, compared with recipients of placebo plus rituximab. In a pivotal phase II trial, idelalisib monotherapy was effective in patients with relapsed indolent NHL who were refractory to rituximab and an alkylating agent, including in the subgroups of patients with follicular lymphoma or SLL. Oral idelalisib had a generally manageable adverse event profile, although episodes of serious/fatal diarrhoea or colitis, hepatotoxicity, pneumonitis and intestinal perforation were reported. In conclusion, idelalisib represents an important advance in the treatment of relapsed CLL and relapsed indolent NHL.