Ibrutinib is a targeted therapy used for the treatment of certain types of blood cancers, specifically chronic lymphocytic leukemia (CLL), mantle cell lymphoma (MCL), and Waldenström macroglobulinemia. It works by blocking a protein called Bruton's tyrosine kinase (BTK), which plays a key role in the growth and survival of cancer cells. Ibrutinib has been shown to be effective in helping to control the growth of cancer cells and improve outcomes for patients with these types of blood cancers. Additionally, it is often used in combination with other treatments to further enhance its effectiveness.