Ibrutinib (PCI-32765) in Waldenstrom's Macroglobulinemia

This research study is a Phase II clinical trial. Phase II clinical trials test the effectiveness of an investigational drug, PCI-32765, to learn whether PCI-32765 works in treating a specific cancer. "Investigational" means that PCI-32765 is still being studied and that research doctors are trying to find out more about it-such as the safest dose to use, the side effects it may cause, and if PCI-32765 is effective for treating different types of cancer. It also means that the FDA has not yet approved PCI-32765 for use in patients, including people with Waldenstrom's Macroglobulinemia. PCI-32765 is a newly discovered drug that is being developed as an anti-cancer agent. PCI-32765 is a Bruton's tyrosine kinase (Btk) inhibitor drug which interrupts B cell receptor (BCR) signaling in lymphomas by selectively and irreversibly binding to the Btk protein, which then results in malignant cell death. This drug has been used in laboratory experiments and other research studies in B-cell malignancies and information from those other research studies suggests that PCI-32765 may be a treatment strategy for B-cell malignancies, including Waldenstrom's Macroglobulinemia. In this research study, the investigators are testing the safety and efficacy of PCI-32765 as a treatment option for relapsed or refractory Waldenstrom's Macroglobulinemia.