Inclusion Criteria:

- Life expectancy more than three months

- diagnosed with multiple myeloma (MM)

- relapsed following a response to any conventional MM therapy, and refractory to their
most recent MM therapy

- Karnofsky performance status = 60

- no electrocardiographic evidence of acute ischemia or new conduction system
abnormalities

- no history of myocardial infarction within last 6 months

- serum concentrations of aspartate aminotransferase (AST) and alanine aminotransferase
(ALT) = 3X upper limit of normal (ULN)

- total serum bilirubin = 2X ULN

- Calculated or measured creatinine clearance >30 mL/min

- platelet count = 30 x 10(9)/L

- hemoglobin concentration = 8 g/dL

- white blood cell count = 2.0 x 10(9)/L

Exclusion Criteria:

- Patients with non-secretory myeloma, plasma cell leukemia, or POEMS syndrome (plasma
cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, M-protein and skin
changes)

- major surgery within four weeks of enrollment

- severe elevated serum calcium

- heart failure

- receipt of chemotherapy within 21 days before enrollment, receiving immunotherapy,
radiation therapy, or other investigational agents

- receipt of corticosteroids equivalent to more than 10 mg/day of prednisone within two
weeks before enrollment

- known allergies to agents used in bortezomib (e.g., boron or mannitol)

- poorly controlled hypertension, diabetes mellitus, or other serious medical or
psychiatric illness that could potentially interfere with the completion of treatment
according to this protocol