Given a context passage, generate a question from the passage such that its answer is shortest continous span from the passage.
One example: In 1582 the united provinces invited francis, duke of anjou to lead them; but after a failed attempt to take antwerp in 1583, the duke left the netherlands again. after the assassination of william of orange (10 july 1584), both henry iii of france and elizabeth i of england declined the offer of sovereignty. however, the latter agreed to turn the united provinces into a protectorate of england (treaty of nonsuch, 1585), and sent the earl of leicester as governor-general. this was unsuccessful and in 1588 the provinces became a confederacy. the union of utrecht is regarded as the foundation of the republic of the seven united provinces, which was not recognized by the spanish empire until the peace of westphalia in 1648.
Solution is here: In what year did francis, duke of anjou leave the netherlands?
Explanation: The generated question is perfect. Because the question is based on second sentence of the input passage and its answer is 1583.

Now, solve this: New treatment options are urgently needed for patients with relapsed chronic lymphocytic leukemia (CLL) who fail to respond to currently available therapies or cannot achieve a sustained response. Moreover, targeted agents with less myelotoxicity are necessary to treat patients with multiple comorbidities who would otherwise be unable to tolerate standard regimens. Ibrutinib, a Bruton's tyrosine kinase inhibitor, has shown highly encouraging results in phase I/II trials in patients with treatment-naive, relapsed and refractory CLL even in the presence of high risk disease or poor prognostic markers. In phase I/II trials, ibrutinib 420 mg or 840 mg - given continuously as single agent or at a dose of 420 mg daily in combination with a monoclonal antibody or chemoimmunotherapy - has been associated with high response rates and durable clinical remissions. Phase II and III trials are currently under way for treatment-naive patients, relapsed/refractory patients, and for those patients harboring a 17p deletion.
Solution:
What is the name of Bruton's tyrosine kinase inhibitor that can be used for treatment of chronic lymphocytic leukemia?