Nitib 140 Capsules Nitib 140 contains Ibrutinib, an orally active, small-molecule inhibitor of Bruton's tyrosine kinase (BTK). It forms a covalent bond with a cysteine residue (Cys-481) in the BTK active site, thereby inhibiting B-cell receptor (BCR) signaling, cell proliferation, and survival in malignant B cells. It is indicated for the treatment of adult patients with Chronic Lymphocytic Leukemia (CLL) / Small Lymphocytic Lymphoma (SLL), Mantle Cell Lymphoma (MCL), Waldenström’s Macroglobulinemia (WM), Marginal Zone Lymphoma (MZL), and Chronic Graft-versus-Host Disease (cGvHD).