TO THE EDITOR:
Complete remissions (CRs) are infrequent in patients with chronic lymphocytic leukemia (CLL) treated with ibrutinib,1 and, unlike in patients treated with chemo-immunotherapy2 or venetoclax,3 it remains uncertain whether there is any correlation between depth of remission and outcome in these patients. In particular, minimal residual disease (MRD) eradication is very rarely achieved with the use of single-agent ibrutinib treatment.1
Also, factors predictive of the depth of remission in CLL patients treated with ibrutinib are lacking. In this regard, the bone marrow (BM) generally constitutes the main site of residual disease during treatment with ibrutinib,1 and cells within the BM microenvironment, such as macrophages, may support the survival of CLL cells during therapy.4
We prospectively assessed responses to therapy, independent of MRD eradication status, in 208 patients with previously untreated or relapsed refractory...