This phase I study will evaluate the feasibility and toxicity of weekly bortezomib in the treatment of relapsed or refractory multiple Myeloma and determine whether a twice-weekly schedule of bortezomib is effective in producing responses in patients with stable disease or progression after weekly bortezomib

Upon determination of eligibility, patients will be receive:

• Bortezomib

Inclusion Criteria:

To be included in this study, you must meet the following criteria:

• Multiple Myeloma
• Received no more than 2 previous treatment regimens for multiple Myeloma
• ECOG performance status 0, 1, or 2
• Serum creatinine < 2.0mg/dL
• calculated or measured creatinine clearance > 30ml/minute
• Measurable or evaluable disease
• Provide written informed consent prior to receiving protocol therapy.

Exclusion Criteria:

You cannot participate in this study if any of the following apply to you:

• Moderate or severe peripheral neuropathy
• Other serious medical conditions
• Other active malignancies
• history of treatment for other invasive cancers
• Women who are pregnant or lactating

Please note: There are additional inclusion/exclusion criteria. The study center will determine if you meet all of the criteria. If you do not qualify for the trial, study personnel will explain the reasons. If you do qualify, study personnel will explain the trial in detail and answer any questions you may have.