Inclusion Criteria:

The patient:

- has a diagnosis of multiple myeloma.

- currently has multiple myeloma with measurable disease.

- must have received at least 1 previous treatment regimen and shows signs of
progressive disease at the time of study entry.

- if a woman of child bearing potential (not surgically sterile or at least 12 months
naturally postmenopausal), must use a medically accepted method of contraception and
must agree to continue use of this method for the duration of the study and for 30
days after participation in the study.

- if a man, must agree to use an acceptable method of contraception throughout the
study and for 90 days after last dose study drug.

- must have an Eastern Cooperative Oncology Group (ECOG) performance status not greater
than 2.

- must have a life-expectancy of greater than 3 months.

- must meet specific protocol-related hematological and laboratory criteria within 14
days of enrollment.

Exclusion Criteria:

The patient has:

- had a prior malignancy within the last 5 years (except for basal or squamous cell
carcinoma, or in situ cancer of the cervix).

- plasma cell dyscrasia with polyneuropathy, organomegaly, endocrinopathy, monoclonal
protein (M-protein) and skin changes (POEMS) syndrome.

- plasma cell leukemia.

- non-measurable multiple myeloma.

- Common Terminology Criteria for Adverse Events (CTCAE) grade 2 (or greater)
peripheral neuropathy within 14 days before enrollment.

- previously participated in a Cephalon-sponsored clinical study with bendamustine.

- impaired cardiac function or clinically significant cardiac diseases.

- undergone major surgery within 4 weeks prior to screening or has not recovered from
side effects of such therapy.

- severe hypercalcemia.

- other concurrent severe and/or uncontrolled medical or psychiatric conditions.

- known positivity for human immunodeficiency virus (HIV) or hepatitis B or C.

- a history of allergic reaction attributable to compounds of similar chemical or
biological composition to bendamustine, bortezomib, boron, or mannitol.

- received chemotherapy within 3 weeks before enrollment, with the exception of
nitrosoureas, which should be discontinued at least 6 weeks before enrollment.

- received corticosteroids (greater than 10 mg/day prednisone or equivalent) within 3
weeks before enrollment.

- received immunotherapy, antibody, or radiation therapy within 4 weeks before
enrollment.

- a status as a pregnant or lactating woman. Any women becoming pregnant during the
study will be withdrawn from the study.

- a status as a male whose sexual partner is a woman of childbearing potential not
using effective birth control.

- used an investigational drug within 1 month before the screening visit.