Deuterated water labeling in ibrutinib-treated patients with CLL: leukemia cell kinetics correlate with IGHV, ZAP-70, and MRD.

Deuterated ("heavy") water labeling in patients with chronic lymphocytic leukemia (CLL) demonstrates that IGHV unmutated and ZAP-70+ patients have higher blood and tissue CLL death rates on ibrutinib therapy, resulting in lower measurable residual disease levels with long-term ibrutinib treatment. This trial was registered at www.clinicaltrials.gov as #NCT01752426.