Monocytic myeloid-derived suppressor cells (MDSCs) were found to increase with ibrutinib (Imbruvica) but not with acalabrutinib (Calquence) treatment in a preclinical model of chronic lymphocytic leukemia (CLL), suggesting a role for ITK inhibition in this cell population, according to results presented at the 2019 European Hematology Association Congress.
“We need to be aware of what drugs are actually doing to the microenvironment and if they're targeting anything else,” said lead study author Arantxa Romero-Toledo, PhD student, at the Centre for Haemato-Oncology, Barts Center Institute. “It's really important to look at the mechanisms of action in other cells.”
For the study, Romero-Toledo and colleagues set out to determine the role of MDSCs in CLL and the impact of the BTK inhibitors ibrutinib and acalabrutinib on 2 major subsets of MDSCs—monocytic and granulocytic cell populations—in vivo. To do this, mice induced with CLL cells were randomized to receive either ibrutinib or acalabrutinib for 21 days. Investigators assessed 15 animals from each group.
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