A Phase II Study of Belinostat in Combination With Bortezomib in Patients With Relapsed, Refractory Multiple Myeloma

Inclusion Criteria:

* Diagnosis of multiple myeloma.
* Status of refractory to or relapsed from at least one prior bortezomib-containing regimen.
* Progressive disease.
* Age \>= 18 years.
* Karnofsky performance status \>= 60%
* Acceptable liver function:

  * Bilirubin =\< 1.5 x ULN (upper limit of normal)
  * Aspartate transaminase (AST) and alanine transaminase (ALT) =\< 3 x ULN
* Acceptable hematologic status:

  * Absolute Neutrophil Count (ANC) \>= 1.5 x 109/L
  * Platelet count \>= 100 x 109/L
  * Hemoglobin \>= 9 g/dL
  * Coagulation status PT-INR/PTT =\< 1.5 x ULN or in the therapeutic range if on anticoagulation therapy. (PT-INR/PTT= prothrombin - international normalized ratio / prothrombin time)
  * Serum potassium within normal range.
* Estimated life expectancy greater than 3 months.
* Signed, written IRB (institutional Review Board)-approved informed consent.

Exclusion Criteria:

* Non-secretory multiple myeloma or symptomatic amyloidosis.
* Hypersensitivity to bortezomib, boron, or mannitol.
* Less than 4 weeks since prior chemotherapy, radiotherapy, endocrine therapy, or immunotherapy, except if disease is rapidly progressing.
* Less than 4 weeks since prior use of other investigational agents.
* Serious concomitant systemic disorders (e.g. active infection).
* Significant cardiovascular disease.
* Marked baseline prolongation of QT/QTc (corrected QT interval)interval.
* Central nervous system disorders requiring neuroleptics / anti-convulsants.
* Peripheral sensory neuropathy of ≥ Grade 2
* Renal insufficiency defined as a creatinine clearance of \< 30 ml/min.
* Non-willingness to use effective contraceptive methods for patients of child-bearing age / potential.
* Pregnant or breast-feeding women.
* Known HIV positivity.
* Prior treatment with belinostat (PXD101), or any other HDAC (histone deacetylase) inhibitor.
* Altered mental status which precludes an understanding of the Informed Consent Document.