Carfilzomib, Rituximab and Dexamethasone in Waldenstrom's Macroglobulinemia

Inclusion Criteria: * Diagnosis of Waldenstrom's Macroglobulinemia * Symptomatic disease * Measurable disease * Life expectancy of greater than 12 weeks * Adequate organ and marrow function * CD20 positive based on any previous performed bone marrow immunohistochemistry or flow cytometric analysis * Disease free of prior malignancies for \>/= 5 years with the exception of currently treated basal cell, squamous cell carcinoma of the skin, or carcinoma "in situ" of the cervix or breast Exclusion Criteria: * More than one prior therapy * Previous therapy with a proteasome inhibitor or rituximab * Chemotherapy or radiotherapy within 4 weeks (6 weeks for nitrosoureas or mitomycin C) prior to entering the study or not recovered from adverse events due to agents administered more than 4 weeks earlier * Currently receiving treatment for any malignancy * Major surgery within 21 days prior to study entry * Acute active infection requiring treatment (systemic antibiotics, antivirals, or antifungals) within 14 days prior to study entry * Uncontrolled hypertension or uncontrolled diabetes * Significant neuropathy (Grades 3-4, or Grade 2 with pain) within 14 days prior to study entry * Known history of allergy to Captisol * Receiving any other study agents * Known brain metastases * History of allergic reactions attributed to compounds of similar chemical or biologic composition to carfilzomib, rituximab, and/or dexamethasone * Contraindication to any of the required concomitant drugs or supportive treatments, including hypersensitivity to all anticoagulation and antiplatelet options, antiviral drugs, or intolerance to hydration due to preexisting pulmonary or cardiac impairment * Uncontrolled intercurrent illness including, but not limited to ongoing or active infection, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements * Pregnant or lactating * HIV-positive on combination antiretroviral therapy