Carfilzomib Consolidation Therapy After Autologous Stem Cell Transplantation (ASCT) for Mantle Cell Lymphoma (MCL), T-cell Lymphoma (TCL), and Diffuse Large B-Cell Lymphoma (DLBCL)

Inclusion Criteria:

1. Patients with mantle cell lymphoma, T-cell lymphoma, and diffuse large b-cell lymphoma within 6 months post autologous transplantation and without relapse.
2. Age \>/= 18 years to \</= 70 years.
3. Absolute neutrophil count (ANC) \>/= to 1.5 x 10\^9/L; Platelets \> 75 x 10\^9/L.
4. No active infection.
5. Performance status: Eastern Cooperative Oncology Group (ECOG) 2 or less or Karnofsky of at least 60.
6. Cardiac EF \>/= 45% by 2D-Echo.
7. Serum creatinine less than 1.6 mg/dl and Creatinine Clearance \>/= to 30 mL/min.
8. Liver function tests less than 2x upper limit of normal range (unless related to medications or Gilbert's disease).
9. Females of childbearing potential who are not pregnant or breastfeeding.
10. Patient or legally authorized representative able to sign informed consent.

Exclusion Criteria:

1. Glucocorticoid therapy (prednisone \>30 mg/day or equivalent within 14 days of first dose.
2. POEMS syndrome.
3. Plasma cell leukemia or circulating plasma cells \>/= 2 X 10\^9/L.
4. Waldenstrom's Macroglobulinemia.
5. Patients with known amyloidosis.
6. Immunotherapy or chemotherapy with approved or investigational anticancer therapeutics within 21 days of first dose.
7. Patients previously randomized in any other Onyx-sponsored Phase 3 trial.
8. Active congestive heart failure (NYHA Class III to IV), symptomatic ischemia, or conduction abnormalities uncontrolled by conventional intervention. Myocardial infarction within 6 months.
9. Acute active infection requiring systemic antibiotics, antiviral (except antiviral directed at Hepatitis B) or antifungal agents within 14 days of first dose.
10. Known HIV seropositive, hepatitis C infection, and/or hepatitis B (except for patients with hepatitis B SAg or core antibody receiving and responding to antiviral therapy directed at hepatitis B: these patients are allowed).
11. Patients with known cirrhosis.
12. Second malignancy within past three years except: a. adequately treated basal or squamous cell skin cancer. b. carcinoma in situ of the cervix. c. prostate cancer \< Gleason Score 6 with stable prostatic specific antigen (PSA) over the past three months. d. breast cancer in situ with full surgical resection. e. treated medullary or papillary thyroid cancer.
13. Patients with myelodysplastic syndrome.
14. Significant neuropathy (Grades 3 to 4, or Grade 2 pain).
15. Known hypersensitivity to carfilzomib.
16. Known contraindication to dexamethasone.
17. Pleural effusions requiring thoracentesis or ascites requiring paracentesis within 14 days of first dose.
18. Any other clinically significant medical disease or psychiatric condition that, in the Investigator's opinion, may interfere with protocol compliance.