The following criteria is provided for health care professionals.

Inclusion Criteria:

• Previously treated myeloma, currently with extramedullary disease (defined as plasmacytoma outside bone marrow that is not contiguous with a bone lesion) with at least one lesion that has a single diameter of >= 2 cm or plasma cell leukemia (defined as circulating plasma cells exceeding 5% of peripheral blood leukocytes or 0.5 X 10^9/L or 200 cells/150000 events by flow cytometry)
• Calculated creatinine clearance (using Cockcroft-Gault equation) >= 30 mL/min
• Absolute neutrophil count (ANC) >= 1000/mm^3
• Platelet count >= 50,000/mm^3
• Hemoglobin >= 8.0 g/dL
• Patients with measurable disease defined as at least one of the following:
  • For patients with extramedullary disease (EMD) measurable disease by computed tomography (CT) or magnetic resonance imaging (MRI) or the CT portion of the positron emission tomography (PET)/CT: must have at least one lesion that has a single diameter of >= 2 cm; skin lesions can be used if the area is >= 2 cm in at least one diameter and measured with a ruler
  • Plasma cell count >= 0.5 X 10^9/L or 5 percent of the peripheral blood white cells
  • Plasma cell count if determined by flow cytometry, >= 200/150,000 events
• Eastern Cooperative Oncology Group (ECOG) performance status (PS) 0, 1 or 2
• Provide informed written consent
• Negative pregnancy test done =< 7 days prior to registration, for women of childbearing potential only
• All study participants must be registered into the mandatory POMALYST (pomalidomide) Risk Evaluation and Mitigation Strategy (REMS™) program, and be willing and able to comply with the requirements of the POMALYST REMS™ program
• Willing to return to enrolling institution for follow-up (during the Active Monitoring Phase of the study)
• Willing to provide bone marrow and blood samples for correlative research purposes

Exclusion Criteria:

• Other malignancy requiring active therapy
  • EXCEPTIONS: Non-melanoma skin cancer, ductal breast carcinoma in situ (DCIS) or carcinoma-in-situ of the cervix
  • NOTE: If there is a history or prior malignancy, they must not be receiving other specific treatment for their cancer
• Females of childbearing potential (FCBP) must have a negative serum pregnancy test with a sensitivity of at least 50 mIU/mL within 10-14 days prior to and again within 24 hours prior to prescribing pomalidomide for cycle 1 (prescriptions must be filled within 7 days as required by RevAssist [lenalidomide REMS program]), and must either commit to continued abstinence from heterosexual intercourse or begin TWO acceptable methods of birth control, one highly effective method and one additional effective method; AT THE SAME TIME, at least 28 days before she starts taking pomalidomide FCBP must also agree to ongoing pregnancy testing; men must agree to use a latex condom during sexual contact with a FCBP even if they have had a successful vasectomy; patient must follow pregnancy testing requirements as outlined in the POMALYST REMS program
• Nursing women
• Men or women of childbearing potential who are unwilling to employ adequate contraception
• Other co-morbidity which would interfere with patient's ability to participate in trial, e.g. uncontrolled infection, uncompensated heart or lung disease
• Other concurrent chemotherapy, radiotherapy, or any ancillary therapy considered investigational
  • NOTE: Bisphosphonates are considered to be supportive care rather than therapy, and are thus allowed while on protocol treatment
• Patient has >= grade 3 peripheral neuropathy, or grade 2 with pain on clinical examination during the screening period
• Major surgery =< 14 days before study registration
• Systemic treatment with strong inhibitors of cytochrome P450, family 1, subfamily A, polypeptide 2 (CYP1A2) (fluvoxamine, enoxacin, ciprofloxacin), strong inhibitors of cytochrome P450, family 3, subfamily A, polypeptide 4 (CYP3A4) (clarithromycin, telithromycin, itraconazole, voriconazole, ketoconazole, nefazodone, posaconazole) or strong CYP3A4 inducers (rifampin, rifapentine, rifabutin, carbamazepine, phenytoin, phenobarbital, Gingko biloba, St. John's wort) within 7 days before registration
• Evidence of current uncontrolled cardiovascular conditions, including cardiac arrhythmias, congestive heart failure, angina, or myocardial infarction within the past 6 months; Note: prior to study entry, any electrocardiogram (ECG) abnormality at screening must be documented by the investigator as not medically relevant
• Corrected QT Interval (QTc) > 470 milliseconds (msec) on a 12-lead ECG obtained during the screening period
  • Note: If a machine reading is above this value, the ECG should be reviewed by a qualified reader and confirmed on a subsequent ECG
• Known human immunodeficiency virus (HIV) positive
• Known hepatitis B surface antigen-positive status, or known or suspected active hepatitis C infection
• Any serious medical or psychiatric illness that could, in the investigator's opinion, potentially interfere with the completion of treatment according to this protocol
• Known allergy to any of the study medications, their analogues or excipients in the various formulations
• Known gastrointestinal (GI) disease or GI procedure that could interfere with the oral absorption or tolerance of ixazomib including difficulty swallowing
• Diarrhea > grade 1, based on the National Cancer Institute Common Terminology Criteria for Adverse Events (NCI CTCAE) grading, in the absence of antidiarrheals