Study of Fluphenazine in Relapsed or Relapsed-and-Refractory Multiple Myeloma

Inclusion Criteria: * Histologically or cytologically confirmed diagnosis of multiple myeloma that is relapsed or relapsed-and-refractory after at least 2 or more prior lines of therapy. Patients must have achieved at least minor response (MR) to at least one prior line of therapy * Progressive disease must have occurred either during or subsequent to the patient's last treatment for multiple myeloma prior to the current enrollment * Measurable disease defined by serum M-protein ≥1 g/dL, or urine light chain ≥200 mg/24 hours, or abnormal serum FLC ratio with involved FLC \> 10 mg/dL provided serum FLC ratio is abnormal * Age \>18 years * Eastern Cooperative Oncology Group (performance status of ≤20 * Life expectancy ≥12 weeks * Signed written informed consent per institutional and federal regulatory requirements * Did not receive chemotherapy (including systemic steroids), immunotherapy (interferon), Imids (thalidomide/lenalidomide), proteasome inhibitors (bortezomib), or radiotherapy for at least 21 days prior to Day 1 of Cycle 1 * Did not receive any investigational treatment for at least 28 days prior to study entry * Absolute granulocyte count of ≥1,000/μL, platelet count ≥50,000/μL, and hemoglobin ≥8.0 g/dL, with no transfusion within the preceding 7 days * Adequate liver function defined by a bilirubin value ≤2 times the upper limit of normal (ULN), and transaminases (AST and ALT) values ≤2.5 times ULN * Adequate renal function defined by a creatinine clearance of ≥30 mL/min * Adequate cardiac function defined by a left ventricular ejection fraction (LVEF) ≥40%, QTc \<450 msec, and no evidence of clinically significant dysrhythmias on ECG * Patient must have substantially recovered from clinically significant toxicities from prior therapies for multiple myeloma * Fertile men and women must agree to use a medically effective contraception method throughout the treatment period. Premenopausal women of reproductive capacity and women less than 24 months post menopause must have a negative serum pregnancy test documented prior to study entry Exclusion Criteria: * Patients who never achieved at least minor response (MR) to at least one prior line of therapy * Clinical spinal cord compression syndromes (unless patient has undergone treatment, for example, surgery or radiation therapy, and neurological findings are ≤ Grade 1 and patient is off corticosteroids for spinal cord edema or on a stable regimen of \< 10 mg/day prednisone equivalent * Clinical signs of brain involvement or leptomeningeal disease * Plasma cell leukemia (plasma cells \> 2000/cubic mm) * Women who are pregnant or breast feeding * Other serious illness or medical condition(s) (see protocol) * Hypersensitivity to fluphenazine or other phenothiazines * Currently being treated with hematopoietic growth factors other than erythropoietin (EPO). Treatment with hematopoietic growth factors may be started during the study with development, or worsening, of cytopenia * Concurrent use of anticholinergics * Concurrent use of phenothiazine and atypical antipsychotics * Concurrent use of anti-seizure drugs, with the exception of gabapentin for treatment of neuropathy * Grade 2 or higher persisting prior treatment-related neuropathy * Concurrent use of systemic steroids with the exception of chronically administered steroids equivalent to ≤ 10 mg/day prednisone if patient has been on this therapy for ≥1month * History of seizures or extrapyramidal symptoms * History of other malignancies within the past 3 years, other than adequately treated non-melanoma skin cancer, or in situ carcinoma of the cervix, unless the other malignancy is quiescent and medical monitor approval is obtained