Inclusion Criteria:

1. Patient with confirmed multiple myeloma requiring systemic therapy. All three
criteria must be met:

- Clonal bone marrow plasma cells > 10%

- Presence of serum and/or urinary monoclonal protein

- Evidence of end-organ damage that can be attributed to the underlying plasma
cell proliferative disorder, specifically:

- Hypercalcemia: serum calcium > 11.5 mg/100 ml or

- Renal insufficiency: serum creatinine > 173 µmol/l

- Anemia: normochromic, normocytic with a hemoglobin value of > 2g/100 ml
below the lower limit of normal or a hemoglobin value < 10g/100 ml

- Bone lesions: lytic lesions, severe osteopenia or pathologic fractures

2. Patient with multiple myeloma relapsing according to the International uniform
response criteria for multiple myeloma (IMWG 2009/ revised Bladé criteria) to one
previous line of treatment

3. Patient with measurable progressive disease defined by at least one of the following
two measurements:

- Serum M-protein ≥ 1 g/dL

- Urine M-protein ≥ 200 mg/24h

Exclusion Criteria:

1. Patient with peripheral neuropathy Grade >2

2. Patient with hypersensitivity to bortezomib, boron or dexamethasone

3. Patient whose disease progressed during or within 60 days of bortezomib treatment or
of any other Multiple Myeloma therapy

4. Patient who received bortezomib within 6 months of randomization to this study

5. Past discontinuation of bortezomib due to associated grade 3 or higher adverse event

6. Patient with contra-indication to high dose of steroids (including ongoing active
infection, use of live vaccines, virosis such as hepatitis, herpes, varicella, herpes
zoster)