To our knowledge, FIRE was the largest French real-word study that assessed the effectiveness and safety of ibrutinib, in accordance with the French marketing authorization in 2016, for the treatment of CLL/SLL in patients who received at least one prior line of treatment, or who were previously untreated and had a del17p and/or TP53 mutation unsuitable for chemoimmunotherapy. The gene discussed is TP53; the disease is B-cell chronic lymphocytic leukemia.