Persistent lymphocytosis with ibrutinib does not indicate early relapse

View on the News

Proof of principle that lymphocytosis is quiescent cells

As more treatments targeting B-cell receptors became available, it was important for physicians to understand that lymphocytosis associated with this treatment was not indicative of treatment resistance or disease aggressiveness. The study by Woyach et al. provides the proof of principle that prolonged lymphocytosis produced by ibrutinib is composed of quiescent leukemic cells and provides a biological rationale in support of the current revisions of CLL [chronic lymphocytic leukemia] response criteria.

Dr. Davide Rossi and Dr. Gianluca Gaidano of the Amedeo Avogadro University of Eastern Piedmont, Alessandria, Italy, provided these comments in an editorial accompanying Dr. Woyach’s study (Blood 2014;123:1772-4). They declared that had no conflicts of interest.



Persistent lymphocytosis lasting more than 12 months in patients with chronic lymphocytic leukemia undergoing treatment with ibrutinib is not associated with a greater likelihood of early relapse.

A prospective observational study in 85 relapsed or refractory patients with chronic lymphocytic leukemia treated with ibrutinib showed lymphocytosis occurred in 77% in patients, persisting at 12 months in 20% of patients.

Dr. Jennifer A. Woyach of Ohio State University, Columbus, and her colleagues found no significant differences in progression-free survival between patients who responded to treatment but showed persistent lymphocytosis, and those with a partial or complete response to treatment without lymphocytosis.

They also found no significant differences in gene expression profiles in persistent lymphocytosis, suggesting that the lymphocytosis most likely represented the movement of quiescent cells (Blood 2014;123:1810-17).

Two authors were unpaid consultants for, three were paid consultants for, and two were employees of Pharmacyclics. One author received research funding from Janssen. The study was funded by the Four Winds Foundation, the Leukemia and Lymphoma Society, and several other organizations. Ibrutinib was provided by Pharmacyclics for in vitro experiments.

Next Article: