MRD in HCL: does it matter?

In this issue of Blood, Kreitman and colleagues update results of a study of moxetumomab pasudotox in patients with relapsed hairy cell leukemia (HCL), demonstrating a high response rate among the 33 patients reported. Among the 32 patients who had minimal residual disease (MRD) assessment in their bone marrow specimens using flow cytometry, median complete remission (CR) duration was significantly longer in the patients who became MRD negative (median 42.1 months vs 13.5 months in the MRD-persistent patients, P < .001). These results support the argument for validity of MRD monitoring in HCL.