This phase II trial studies side effects and how well bendamustine hydrochloride, bortezomib, and dexamethasone work in treating patients with newly diagnosed multiple myeloma. Drugs used in chemotherapy, such as bendamustine hydrochloride and dexamethasone, work in different ways to stop the growth of cancer cells, either by killing the cells, by stopping them from dividing, or by stopping them from spreading. Bortezomib may stop the growth of cancer cells by blocking some of the enzymes needed for cell growth. Giving bendamustine hydrochloride with bortezomib and dexamethasone may kill more cancer cells.

PRIMARY OBJECTIVES:

I. Establish the response rate of induction therapy following 4 cycles of the combination regimen bendamustine (bendamustine hydrochloride), bortezomib and dexamethasone (BBd) in patients with newly diagnosed multiple myeloma.

II. Describe the tolerability and toxicities of this regimen. III. Provide one-year progression-free survival and one-year overall survival data following this therapeutic strategy.

OUTLINE:

Patients receive bendamustine hydrochloride intravenously (IV) over 30 minutes on days 1 and 2; bortezomib subcutaneously (SC) on days 1, 8, 15, and 22; and dexamethasone orally (PO) on days 1, 8, 15, and 22. Treatment repeats every 35 days for 4 courses in the absence of disease progression or unacceptable toxicity. Patients achieving less than a very good partial response (VGPR) or with more than 10% bone marrow plasmacytosis may receive 2 additional courses.

NOTE: Patients requiring immediate reduction in paraprotein during course 1 only receive bendamustine hydrochloride IV over 30 minutes on days 1 and 2; bortezomib IV on days 1, 4, 8, and 11; and dexamethasone PO on days 1-4.

After completion of study treatment, patients are followed up for 1 year.

Inclusion Criteria:

1. New diagnosis of multiple myeloma with no prior history of systemic treatment (Exceptions include corticosteroids, bisphosphonates, single agent cyclophosphamide, <= 21 days of the first cycle of a planned regimen
2. >= 18 years of age
3. ECOG <= 3
4. Signed informed consent
5. Measurable serum paraprotein on SPEP or serum free light chains and ratio, or quantifiable Bence-Jones proteinuria on 24 hour urine specimen. If the monoclonal protein has merged with the beta region we will follow the serum immunoglobulin of the involved heavy chain and comment on either partial remission (PR, as judged by two protocol investigators) or complete remission (CR, as defined by the achievement of PR as above and the resolution of the monoclonal protein by immunofixation in the serum and urine.)

Exclusion Criteria:

1. Failure to sign informed consent
2. Smoldering myeloma, monoclonal gammopathy of undetermined significance (MGUS), or plasma cell leukemia
3. History of previously treated smoldering myeloma
4. Grade 3 or above peripheral neuropathy
5. Uncontrolled human immunodeficiency virus (HIV)
6. Active hepatitis A, B or C
7. Pregnant or lactating females
8. Total bilirubin >3 times the upper limit of normal
9. ASLT/ALT > 2.5 times the upper limit of normal