In this trial, we plan to evaluate further the role of arsenic trioxide in the treatment of patients with refractory multiple myeloma. Arsenic trioxide will be used in combination with thalidomide. Although both drugs have a similar mechanism of action, it is likely that the mechanisms may be additive or synergistic. Since neither drug produces much myelosuppression, this combination regimen should be tolerable in patients with compromised marrow function due to involvement with myeloma and/or previous cytotoxic chemotherapy

Upon determination of eligibility, patients will be receive:

• Arsenic Trioxide + Thalidomide

Inclusion Criteria:

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

• Confirmed diagnosis of multiple Myeloma
• Received at least one previous chemotherapy regimen at most 3 previous
• Thalidomide with or without dexamethasone without chemotherapy will not factor in to total number of regimens.
• Age at least 18 years years
• Able to perform activities of daily living with minimal assistance
• Life expectancy more than 3 months
• Adequate bone marrow, liver and kidney function
• Must give written informed consent in order to participate.

Exclusion Criteria:

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

• Women pregnant or lactating.
• Pre-existing moderate neuropathy
• Patients with significant underlying cardiac dysfunction
• Uncontrolled hypercalcemia
• Active serious infections not controlled by antibiotics
• History of grand mal seizures (other than infantile febrile seizures)
• Receiving other medications that prolong the QT interval.

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.