A Phase II Study of Carfilzomib in Relapsed Waldenström's Macroglobulinemia (WM) IST-CAR-531

Inclusion Criteria: * Biopsy proven WM with relapsed/refractory symptomatic disease are eligible for enrollment. * Bone marrow lymphoplasmacytosis with: * \> 10% lymphoplasmacytic cells (measured within 28 days prior to registration OR * Aggregates or sheets of one of the following: lymphocytes, plasma cells or lymphoplasmacytic cells on the bone marrow biopsy (measured within 28 days prior to registration). * Measurable disease defined as a quantitative IgM monoclonal protein of \>500 mg/dL obtained within 28 days prior to registration * CD20+ bone marrow or lymph node by immunohistochemistry or flow cytometry obtained within 28 days prior to registration * Lymph node biopsy must be done \<28 days prior to registration if used as an eligibility criterion for study entry. * Symptomatic disease, as defined by the IWWM, includes the following criteria: Hemoglobin less than 10 g/dL, platelet count less than 100,000 uL, bulky adenopathy or organomegaly, symptomatic hyperviscosity syndrome, severe neuropathy, amyloidosis, cryoglobulinemia, cold agglutinin disease, or evidence of transformation high-grade non-Hodgkin's lymphoma. * Patients must not be receiving concurrent steroids \> 10 mg prednisone (or equivalent) per day. * Prior irradiation is allowed if \> 28 days prior to registration have elapsed since the date of last treatment. * Women must not be pregnant or breast-feeding due to the fact that the reproductive risk to humans taking carfilzomib is unknown. All …