DISEASE CHARACTERISTICS:

• Histologically and clinically confirmed multiple myeloma

  • Relapsed or refractory disease after prior chemotherapy or transplantation* NOTE: *Patients relapsing after prior allogeneic transplantation are eligible only if they have no evidence of active graft-versus-host disease requiring immune suppression

• Measurable disease, defined by quantitative immunoglobulin levels in serum and/or urine and bone marrow plasmacytosis

  • Non-secretory disease allowed provided MRI or positron emission tomography or CT scan can accurately measure at least one plasmacytoma lesion
• No known CNS involvement

PATIENT CHARACTERISTICS:

• Life expectancy > 3 months
• ECOG performance status (PS) 0-2 OR Karnofsky PS 60-100%
• Absolute neutrophil count ≥ 1,000/mm³ (unless myelosuppression is secondary to bone marrow plasmacytosis [> 80% involvement])
• Platelet count ≥ 50,000/mm³ (unless myelosuppression is secondary to bone marrow plasmacytosis [> 80% involvement])
• Bilirubin ≤ 2 times upper limit of normal (ULN)
• AST and ALT ≤ 2 times ULN
• Creatinine < 2 mg/dL OR creatinine clearance > 40 mL/min
• Not pregnant or nursing
• Negative pregnancy test
• Fertile patients must use effective contraception
• Able to swallow pills
• Patients with a history of seizures are eligible provided seizures are under adequate control with non-enzyme inducing anticonvulsant medication
• No history of allergic reactions attributed to study agents
• No sensory or motor neuropathy ≥ grade II

• No uncontrolled current illness including, but not limited to, the following:

  • Ongoing or active infection
  • Symptomatic congestive heart failure
  • Unstable angina pectoris
  • Cardiac arrhythmia
  • Psychiatric illness or social situation that would limit study compliance
• No grade 3 QT prolongation (i.e., > 500 msec) at baseline

PRIOR CONCURRENT THERAPY:

• See Disease Characteristics
• Prior bortezomib allowed
• At least 2 weeks since prior therapy for multiple myeloma
• Concurrent growth factors (filgrastim [G-CSF] and epoetin alfa) to sustain peripheral blood counts (during the first course of therapy only) allowed
• Concurrent steroid therapy (≤ 20 mg of prednisone) for patients requiring chronic use for disorders other than myeloma allowed
• No concurrent combination antiretroviral therapy for HIV-positive patients
• No other concurrent investigational or commercial agents or therapies for this malignancy