NCIt definition : The maleate monohydrate form of acalabrutinib, an orally available inhibitor of Bruton's
tyrosine kinase (BTK) with potential antineoplastic activity. Upon administration,
acalabrutinib inhibits the activity of BTK and prevents the activation of the B-cell
antigen receptor (BCR) signaling pathway. This prevents both B-cell activation and
BTK-mediated activation of downstream survival pathways. This leads to an inhibition
of the growth of malignant B cells that overexpress BTK. BTK, a member of the src-related
BTK/Tec family of cytoplasmic tyrosine kinases, is overexpressed in B-cell malignancies;
it plays an important role in B lymphocyte development, activation, signaling, proliferation
and survival.;