Inclusion Criteria:
DISEASE CHARACTERISTICS:
* Histologically confirmed multiple myeloma
* Relapsed or relapsed/refractory disease
* Failed ≥ 1 prior therapy for multiple myeloma
* Once the MTD is defined, only patients who have received at least 1 but equal or less than 6 prior chemotherapy regimens will be enrolled at this dose level
* CD56-positive disease confirmed by immunohistochemistry or flow cytometry
PATIENT CHARACTERISTICS:
* ECOG (Zubrod) performance status 0-2
* Life expectancy ≥ 12 weeks
* Platelet count ≥ 75,000/mm\^3
* Absolute neutrophil count \> 1,000/mm\^3
* Hemoglobin ≥ 8.5 g/dL
* AST and ALT ≤ 3 times upper limit of normal (ULN)
* Bilirubin ≤ 1.5 times ULN
* Amylase and lipase within normal limits
* Creatinine ≤ 2 mg/dL
* Left ventricular ejection fraction ≥ lower limit of normal on MUGA or ECHO
* Not pregnant or nursing
* Negative pregnancy test
* Fertile patients must use effective contraception
* No peripheral neuropathy ≥ grade 3 or painful grade 2 neuropathy
* No significant cardiac disease, including any of the following:
* Myocardial infarction within the past 6 months
* Unstable angina
* Uncontrolled congestive heart failure
* Uncontrolled hypertension (i.e., recurrent or persistent increases in systolic blood pressure ≥ 180 mm Hg or diastolic blood pressure ≥ 110 mm Hg)
* Uncontrolled cardiac arrhythmias
* Cardiac toxicity ≥ grade 3 after prior chemotherapy
* No history of multiple sclerosis or other demyelinating disease
* No hemorrhagic or ischemic stroke within the past 6 months
* No Eaton-Lambert syndrome (para-neoplastic syndrome)
* No CNS injury with residual neurological deficit (other than peripheral neuropathy ≤ grade 2)
* No other malignancy within the past 3 years except adequately treated basal cell or squamous cell skin cancer, in situ cervical cancer, in situ breast cancer, or in situ prostate cancer
* No clinically relevant active infection, including active hepatitis B or C infection or HIV infection
* No other condition or disease, including laboratory abnormalities, that, in the opinion of the investigator, may preclude study treatment
* No known recent biochemical or clinical evidence of pancreatitis or extensive metastatic disease involving the pancreas
PRIOR CONCURRENT THERAPY:
* See Disease Characteristics
* At least 4 weeks since prior chemotherapy (6 weeks for nitrosoureas or mitomycin C)
* At least 4 weeks since prior radiotherapy
* At least 4 weeks since prior major surgery (except placement of a vascular access device or tumor biopsies)
* More than 4 weeks since prior investigational agents
* At least 2 weeks since prior antineoplastic therapy with biological agents
* No prior hypersensitivity to monoclonal antibody therapy
* No other concurrent investigational agents
* No concurrent corticosteroids (except as indicated for other medical conditions \[\< 10 mg prednisone or equivalent\]; as pre-medication for administration of certain medications or blood products \[≤ 100 mg hydrocortisone\]; or for treatment of infusion reactions)
* Concurrent topical steroids allowed
* No other concurrent antineoplastic treatment (e.g., chemotherapy, radiotherapy, or biological agents)
* Concurrent bisphosphonates allowed provided patient began bisphosphonates before study entry and is maintained on a stable dose during study treatment
