Bortezomib and Dexamethasone in Treating Patients With Multiple Myeloma That Has Relapsed or Has Not Responded to Treatment

DISEASE CHARACTERISTICS:

Diagnosis of multiple myeloma

Refractory or relapsed disease meeting the following criteria:

Primary refractory disease and first-line relapsing disease
Progressive disease after last therapy

PATIENT CHARACTERISTICS:

ECOG performance status 0-2
Life expectancy > 3 months

Platelet count ≥ 50,000/mm³ (≥ 30,000/mm³ for patients with significant bone marrow involvement)

Transfusions allowed
Hemoglobin ≥ 7.5 g/dL
Absolute neutrophil count ≥ 750/mm³
Serum calcium < 14 mg/dL
AST and ALT < 2.5 times upper limit of normal
Creatinine clearance ≥ 30 mL/min
Not pregnant or nursing
Negative pregnancy test
Fertile patients must use effective contraception
No peripheral neuropathy ≥ grade 2 within the past 14 days
No hypersensitivity to boron or mannitol

No cardiovascular complications, including any of the following:

Myocardial infarction within the past 6 months
New York Heart Association class III-IV heart failure
Uncontrolled angina
Ventricular arrhythmias
Electrocardiographic evidence of acute ischemia or active conduction system abnormalities
Cardiac amyloidosis
No other cancer or treatment for cancer other than basal cell cancer of the skin within the past 5 years
No poorly controlled chronic diseases (e.g., diabetes mellitus or hypertension)
No HIV positivity
No hepatitis B surface antigen or active hepatitis C infection
No active systemic infection requiring therapy
No serious medical or psychiatric illness that would interfere with study participation

PRIOR CONCURRENT THERAPY:

No plasmapheresis within the past 4 weeks
No major surgery within the past 4 weeks
No prior bortezomib
No chemotherapy (e.g., clarithromycin) within the past 4 weeks
No radiotherapy within the past 3 weeks
No corticosteroids (> 10 mg/day of prednisone or equivalent) within the past 3 weeks
No other immunotherapy within the past 8 weeks
No other investigational drugs within the past 14 days
No concurrent participation in other clinical research studies