In the European Union, idelalisib is indicated, in combination with rituximab or ofatumumab, for the treatment of patients with relapsed CLL, as first-line therapy in CLL patients with the 17p deletion or TP53 mutation who are deemed unsuitable for chemoimmunotherapy, and as monotherapy for patients with refractory FL (5). Here, TP53 is linked to B-cell chronic lymphocytic leukemia.