Inclusion Criteria:

1. Patient was previously diagnosed with multiple myeloma based on standard criteria
treated with at least one, but less than 4 lines of therapy, and currently requires
further treatment because of relapse from CR or PD.

2. Patient previously treated with bortezomib will be included in the study, if the
duration of response was >6mths from the completion of therapy.

3. Patient's age is > 18 yrs

4. Patient is, in the investigator's opinion, willing and able to comply with the
protocol requirements.

5. Patient has given voluntary written informed consent.

6. Female patients of child-bearing potential and male patients with female partners of
child-bearing potential, one of whom has not undergone surgical sterilisation must
agree to use 2 simultaneous methods of contraception. For female patients, a negative
pregnancy test is to be performed within 7 days prior to administration of study
drugs.

7. Patient has measurable disease.

- serum monoclonal protein (SEP) > 5 g/L

- serum-free light chains (SFLC) > 100 mg/L

- urine-free light chains (UFLC) > 200 mg/24hr

- measurable soft tissue (not bone) plasmacytoma (STPC)

8. Patient has a Karnofsky performance status ≥80%.

9. Patient has a life-expectancy >3 months.

10. Patient has the following laboratory values within 14 days before study drug
administration:

- Platelet count ≥50 × 109/L without transfusion support within 7 days

- Hemoglobin ≥75 g/L without transfusion support within 7 days

- Absolute neutrophil count (ANC) ≥0.75 × 109/L without the use of growth factors.

- Corrected serum calcium <14 mg/dL (3.5 mmol/L).

- Serum potassium ≥ 4.0 mmol/L and serum magnesium ≥ 0.85 mmol/L (electrolytes can
be corrected with supplementation. See section 9.7).

- Aspartate transaminase (AST): ≤2.5 × the upper limit of normal (ULN).

- Alanine transaminase (ALT): ≤2.5 × the ULN.

- Total bilirubin: ≤1.5 × the ULN.

- Calculated or measured creatinine clearance: ≥20 mL/minute.

Exclusion Criteria:

1. Prior severe allergic reactions to bortezomib (Velcade), romidepsin, boron or
mannitol

2. Neuropathy > Grade 3 or Neuropathy of Grade 2 with pain > Grade 1 by NCI-CTCAE
criteria (v3.0).

3. Patients with the following cardiac risk factors will be excluded from the study (as
per the previous NCI trials):

- Congenital long QT syndrome

- QTc interval > 480 milliseconds

- Patients who have had a myocardial infarction within 12 months of study entry.

- Patients who have active coronary artery disease, e.g. angina as defined by
Canadian Class II-IV (Appendix 3).

- Patients with an ECG showing evidence of cardiac ischemia (ST depression of ≥ 2
mm).

- Patients with congestive heart failure that meets NYHA Class II to IV
definitions (Appendix 4) and/or ejection fraction < 45% by MUGA scan or < 50% by
echocardiogram and/or MRI.

- Patients with a history of sustained VT, VF, Torsade de Pointes, or cardiac
arrest unless currently addressed with an automatic implantable cardioverter
defibrillator (AICD).

- Patients with dilated, hypertrophic, or restrictive cardiomyopathy from prior
treatment or other causes (in doubt, see ejection fraction criteria above).

- Patients with uncontrolled hypertension, i.e. SBP ≥ 160 mm Hg or DBP ≥ 95 mm Hg.

- Patients with cardiac arrhythmia requiring anti-arrhythmic medication other than
beta blocker or calcium channel blocker. Patients in whom digitalis cannot be
discontinued are excluded from study.

- Patients with Mobitz II second degree heart block, that do not have a pacemaker.

Note: Patients with other cardiac disease may be excluded at the discretion of the
principal investigator following consultation with cardiologist.

4. Pregnancy in female patients