Ibrutinib showed significant impact on circulating malignant and nonmalignant immune cells and was found to restore healthy T-cell function in patients with chronic lymphocytic leukemia (CLL), according to the results of a comparative study of CLL patients and healthy controls.
Researchers compared circulating counts of 21 immune blood cell subsets throughout the first year of treatment in 55 patients with relapsed/refractory (R/R) CLL from the RESONATE trial and 50 previously untreated CLL patients from the RESONATE-2 trial with 20 untreated age-matched healthy donors, according to a report published online in Leukemia Research.
In addition, T-cell function was assessed in response to T-cell–receptor stimulation in 21 patients with R/R CLL, compared with 18 age-matched healthy donors, according to Isabelle G. Solman, MS, an employee of Translational Medicine, Pharmacyclics, Sunnyvale, Calif. and colleagues.
Positive indicators
Ibrutinib significantly decreased pathologically high circulating B cells, regulatory T cells, effector/memory CD4+ and CD8+ T cells (including exhausted and chronically activated T cells), natural killer (NK) T cells, and myeloid-derived suppressor cells; preserved naive T cells and NK cells; and increased circulating classical monocytes, according to the researchers.
Ibrutinib also significantly restored T-cell proliferative ability, degranulation, and cytokine secretion. Over the same period, ofatumumab or chlorambucil did not confer the same spectrum of normalization as ibrutinib in multiple immune subsets that were examined, they added.
“These results establish that ibrutinib has a significant and likely positive impact on circulating malignant and nonmalignant immune cells and restores healthy T-cell function,” the researchers indicated.
“Ibrutinib has a significant, progressively positive impact on both malignant and nonmalignant immune cells in CLL. These positive effects on circulating nonmalignant immune cells may contribute to long-term CLL disease control, overall health status, and decreased susceptibility to infection,” they concluded.
The study was funded by Pharmacyclics, an AbbVie Company. Ms. Solman is an employee of Translational Medicine, Pharmacyclics, Sunnyvale, Calif. as were several other authors.
SOURCE: Solman IG et al. Leuk Res. 2020;97. doi: 10.1016/j.leukres.2020.106432.