Pralatrexate + Romidepsin in Relapsed/Refractory Lymphoid Malignancies

Inclusion Criteria: Phase I: Patients must have histologically confirmed relapsed or refractory Non-Hodgkin's lymphoma, Hodgkin's Disease or multiple myeloma (defined by World Health Organization (WHO) criteria). Phase II: Patients must have histologically confirmed relapsed or refractory T-Cell Lymphoma (as defined by WHO criteria). * Must have received first line chemotherapy. No upper limit for the number of prior therapies * Evaluable Disease * Age ≥18 years * Eastern Cooperative Oncology Group (ECOG) performance status ≤2 * Patients must have adequate organ and marrow function as defined in the protocol * Adequate Contraception * Ability to understand and the willingness to sign a written informed consent document * Inclusion Criteria for Multiple Myeloma patients specified in the protocol Exclusion Criteria: * Prior Therapy * Exposure to chemotherapy or radiotherapy within 2 weeks (6 weeks for nitrosureas or mitomycin C) prior to entering the study or those who have not recovered from adverse events due to agents administered more than 2 weeks earlier * Systemic steroids that have not been stabilized to the equivalent of ≤10 mg/day prednisone prior to the start of the study drugs * No other investigational agents are allowed * Central nervous system metastases, including lymphomatous meningitis * History of allergic reactions to Pralatrexate or Romidepsin * Uncontrolled intercurrent illness * Pregnant women * Nursing women * Current malignancy or history of a prior malignancy, as outlined in the protocol * Patient known to be Human Immunodeficiency Virus (HIV)-positive * Active Hepatitis A, Hepatitis B, or Hepatitis C infection