Inclusion Criteria:

- Voluntary written informed consent before performance of any study-related procedure
not part of normal medical care, with the understanding that consent may be withdrawn
by the subject at any time without prejudice to future medical care.

- Female subject is either post-menopausal or surgically sterilized or willing to use
an acceptable method of birth control (ie, a hormonal contraceptive, intra-uterine
device, diaphragm with spermicide, condom with spermicide, or abstinence) for the
duration of the study.

- Male subject agrees to use an acceptable method for contraception for the duration of
the study.

- Multiple Myeloma Criteria:

- Patients with primary refractory disease (those failing to achieve at least a partial
response, as defined by the Bladé multiple myeloma response criteria, after
first-line (induction) therapy). A partial response will be defined as the following:
≥50% reduction in the level of the serum monoclonal paraprotein, maintained for a
minimum of 6 weeks, Reduction in 24-hour urinary light chain excretion either by ≥90%
or to <200 mg, maintained for a minimum of 6 weeks. For patients with non-secretory
myeloma only, ≥50% reduction in plasma cells in a bone marrow aspirate and biopsy,
maintained for a minimum of 6 weeks, ≥50% reduction in the size of soft tissue
plasmacytomas (by radiography or physical examination). No increase in the size or
number of lytic bone lesions (development of a compression fracture does not exclude
response).

- Patients with plasma cell leukemia, either newly diagnosed or previously treated.

- Patients greater than or equal to 18 years of age are eligible.

- Patients must have a histologically confirmed diagnosis by a pathologic review at the
H. Lee Moffitt Cancer Center and Research Institute.

- Patients must have undergone a complete psychosocial evaluation and have been
considered capable of compliance.

Exclusion Criteria:

- Patient has a platelet count of <30× 109/L within 14 days before enrollment.

- Patient has an absolute neutrophil count of <1.0 × 109/L within 14 days before
enrollment.

- Patient has a serum creatinine of greater than 2.0 mg/dL OR a creatinine clearance of
less than 40 ml/minute within 14 days before enrollment. Creatinine clearance can be
measured or calculated.

- Subjects with >Grade 2 peripheral neuropathy within 14 days before enrollment.

- Myocardial infarction within 6 months prior to enrollment or has New York Hospital
Association (NYHA) Class III or IV heart failure (see section 8.4), uncontrolled
angina, severe uncontrolled ventricular arrhythmias, or electrocardiographic evidence
of acute ischemia or active conduction system abnormalities. Prior to study entry,
any ECG abnormality at screening has to be documented by the investigator as not
medically relevant.

- Patient has hypersensitivity to bortezomib, boron or mannitol.

- Female subject is pregnant or breast-feeding. Confirmation that the subject is not
pregnant must be established by a negative serum β-human chorionic gonadotropin
(β-hCG) pregnancy test result obtained during screening. Pregnancy testing is not
required for postmenopausal or surgically sterilized women.

- Patient has received other investigational drugs with 14 days before enrollment

- Serious medical or psychiatric illness likely to interfere with participation in this
clinical study.

- Patients with a DLCO less than 50% (adjusted) of normal or with symptomatic
obstructive or restrictive lung disease are ineligible.

- Patients with renal dysfunction secondary to multiple myeloma may be enrolled at the
discretion of the principal investigator. However, patients on hemodialysis or
peritoneal dialysis are ineligible.

- Patients with a total bilirubin greater than 2.0 mg/dL and SGOT or SGPT greater than
two and a half times normal (unless due to primary malignancy), or a history of
severe hepatic dysfunction are ineligible.

- Patients with active infections are ineligible.

- Patients who are HIV positive are ineligible.

- Patients with active leptomeningeal involvement are ineligible. Patients with a
history of previous CSF tumor involvement without symptoms or signs are eligible
provided the CSF is now free of disease on lumbar puncture, and MRI of the brain
shows no tumor involvement. Patients with severe symptomatic CNS disease of any
etiology are ineligible.

- Patients with uncontrolled insulin-dependent diabetes mellitus or uncompensated major
thyroid or adrenal dysfunction are ineligible.

- Patients with an ECOG performance status of ≥ 2 are ineligible See section 8.9).

- Patients with an ECOG performance status of 2 to 3, secondary to bone pain, may be
enrolled at the discretion of the institutional investigator(s).