Nitib 140mg (Ibrutinib) is a prescription anticancer medication. It belongs to a class of drugs known as Bruton's tyrosine kinase (BTK) inhibitors. Nitib 140mg (generic: Ibrutinib) is an anti-cancer medication used to treat blood cancers like chronic lymphocytic leukemia (CLL) and mantle-cell lymphoma. It acts as a Bruton's tyrosine kinase (BTK) inhibitor to block the abnormal proteins that help cancer cells multiply.