BTK and B-cell chronic lymphocytic leukemia: The longer median OS in the LT-CLL-2s study (68 months) compared to the LT-CLL001 study (31 months) may have been due to the lower number of high-risk patients (TP53 mut/17p del 20% vs. 44%, IgHV unmutated, 68% vs. 86%, fludarabine refractory 8% vs. 34%), the higher availability for BTK inhibitors as salvage therapy (36% vs. 5% of patients), and a significantly lower toxicity (treatment related mortality 0% vs. 10%) in the LT-CLL-2s study.