Inclusion Criteria

Key Inclusion Criteria (Part 3):

- Patients should have received at least two prior treatment regimens.

- Confirmed refractory MM (measurable disease) or PCL. Patients must be refractory to
treatment with both lenalidomide/dexamethasone and bortezomib/dexamethasone (or to
treatment with bortezomib/lenalidomide/dexamethasone), defined as documented
progressive disease on therapy or within 60 days of completing treatment with these
regimens.

- Previously received adequate alkylator therapy.

- Eastern Cooperative Oncology Group (ECOG) performance status (PS) of 0 or 1.

- Adequate hematology laboratory values without transfusion support within 2 weeks of
screening.

- Adequate liver and renal function.

- Additional criteria exist.

Key Exclusion Criteria (Part 3):

- Primary amyloidosis.

- Concomitant malignancies or previous malignancies with less than a 3-year disease
free interval at the time of enrollment (patients with adequately resected basal or
squamous cell carcinoma of the skin, carcinoma in situ of the cervix or Stage A low
grade prostate cancer may enroll irrespective of the time of diagnosis).

- Autologous or allogeneic stem cell or bone marrow transplant within 3 months prior to
first dose of study drug.

- Cytotoxic therapy or monoclonal antibodies within 21 days prior to first dose of
study drug.

- Radiotherapy within 21 days prior to first dose of study drug (if the radiation
portal covered ≤ 5% of the bone marrow reserve, the patient may be enrolled
irrespective of the end date of radiotherapy).

- Corticosteroid doses > 10 mg/day of prednisone or equivalent within 2 weeks prior to
first dose of study drug.

- Known positive serology for the human immunodeficiency virus (HIV), hepatitis B
and/or active hepatitis C.

- Additional criteria exist.