Chronic Lymphocytic Leukemia Therapy Guided by Measurable Residual Disease

To the Editor: In their article on the latest FLAIR platform trial involving patients with chronic lymphocytic leukemia (CLL), Munir and colleagues (Jan. 25 issue) 1 found that the percentage of patients with undetectable measurable residual disease (MRD) in blood and bone marrow was higher among those who had received ibrutinib–venetoclax therapy guided by MRD testing than among those who had received fludarabine–cyclophosphamide–rituximab (FCR) therapy. Moreover, the ibrutinib–venetoclax group also had longer progression-free survival and overall survival. Despite these data, the value of MRD testing in CLL is controversial, especially regarding whether undetectable MRD is the appropriate surrogate for predicting progression-free . . .