Phase 2 Study of Carfilzomib in Relapsed Multiple Myeloma

Inclusion Criteria: Disease Related * Multiple myeloma * Subjects must have measurable disease, defined as one or more of the following: * Serum M-protein ≥ 1 g/dL * Urine M-protein ≥ 200 mg/24 hours * Subjects must have been responsive (i.e., achieve a minimal response \[MR\] or better) to standard, first line therapy * Relapsed and/or refractory or progressive disease after at least one, but no more than three, prior therapeutic treatments or regimens for multiple myeloma. Refractory disease is defined as ≤ 25% response or progression during therapy or within 60 days after completion of therapy. Induction therapy and stem cell transplant will be considered as one regimen Demographic * Males and females ≥18 years of age * Life expectancy of more than three months * Eastern Cooperative Oncology Group (ECOG) Performance Status of 0-2 Laboratory * Adequate hepatic function, with bilirubin \< 2.0 times the upper limit of normal, and aspartate aminotransferase (AST) and alanine aminotransferase (ALT) of \< 3.0 times the upper limit of normal * Uric acid, if elevated, must be corrected to within laboratory normal range prior to dosing * Total white blood cell (WBC) count ≥ 2,000/mm³, absolute neutrophil count \> 1,000/mm³, hemoglobin ≥ 8.0 g/dL, and platelet count \> 50,000/mm³ * Subjects should be platelet transfusion independent * Screening absolute neutrophil count (ANC) should be independent of granulocyte colony stimulating factor (G-CSF) or granulocyte macrophage colony stimulating factor (GM-CSF) support for ≥ 1 week and of pegylated G-CSF for ≥ 2 weeks * Subjects may receive red blood cell (RBC) transfusion or receive supportive care such as erythropoietin and darbepoetin in accordance with institutional guidelines * Calculated or measured creatinine clearance of ≥ 30 mL/minute, calculated using the formula of Cockcroft and Gault \[(140 - Age) X Mass (kg) / (72 X Creatinine mg/dL)\]. Multiply result by 0.85 if female. * Serum creatinine ≤ 2 mg/dL Ethical / Other * Written informed consent in accordance with federal, local, and institutional guidelines * Female subjects of child-bearing potential must have a negative serum pregnancy test within seven days of the first dose and agree to use dual methods of contraception during and for 3 months following last dose of drug. Post menopausal females (\> 45 years old and without menses for \> 1 year) and surgically sterilized females are exempt from a pregnancy test. Male subjects must use an effective barrier method of contraception during study and for 3 months following the last dose if sexually active with a female of child-bearing potential. * Subjects must be able to receive outpatient treatment and laboratory monitoring at the institute that administers agent. Exclusion Criteria: Disease Related * Multiple Myeloma Immunoglobulin M (IgM) * Subjects previously treated with any proteasome inhibitor (for Part 2 Proteasome Inhibitor - Naïve only, criteria added at Amendment 2) * Subjects must not be primary refractory to standard first-line therapy * Subjects with non-secretory multiple myeloma, defined as \< 1 g/dL M-protein in serum, \< 200 mg/24 hour M-protein in urine * Subjects with disease measurable only by serum free light chain (SFLC) analysis * Glucocorticoid therapy (prednisone \>10 mg/day orally or equivalent) within the last three weeks * POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, and skin changes) * Plasma cell leukemia * Chemotherapy with approved or investigative anticancer therapeutics, including steroid therapy, within the three weeks prior to first dose * Radiation therapy or immunotherapy in the previous four weeks; localized radiation therapy within 1 week prior to first dose * Participation in an investigational therapeutic study within three weeks or within five drug half-lives (t1/2) prior to first dose, whichever time is greater * Prior treatment with carfilzomib Concurrent Conditions * Major surgery within three weeks before Day 1 * Congestive heart failure (New York Heart Association class III to IV), symptomatic ischemia, conduction abnormalities uncontrolled by conventional intervention, or myocardial infarction in the previous six months * Acute active infection requiring systemic antibiotics, antivirals or antifungals within 2 weeks prior to first dose * Known or suspected human immunodeficiency (HIV) infection or subjects who are HIV seropositive * Active hepatitis A, B, or C infection * Non-hematologic malignancy within the past three years except a) adequately treated basal cell or squamous cell skin cancer, b) carcinoma in situ of the cervix, or c) prostate cancer \< Gleason Grade 6 with stable prostate-specific antigen (PSA) * Subjects with treatment related myelodysplastic syndrome * Significant neuropathy (Grade 3, 4 or Grade 2 with pain) at the time of study initiation * Subjects with known contraindication to receiving allopurinol * Subjects in whom the required program of oral and intravenous fluid hydration is contraindicated, e.g., due to pre-existing pulmonary, cardiac, or renal impairment * Subjects with known or suspected amyloidosis Subjects with pleural effusions requiring thoracentesis or ascites requiring paracentesis * Any clinically significant medical disease or condition that, in the Investigator's opinion, may interfere with protocol adherence or a subject's ability to give informed consent Ethical / Other * Female subjects who are pregnant or lactating * Serious psychiatric or medical conditions that could interfere with treatment