Mocetinostat (MGCD0103) Plus Brentuximab Vedotin (SGN-35) in Patients With Relapsed or Refractory Hodgkin Lymphoma

Inclusion Criteria: * Patients must have histologically confirmed CD30 positive relapsed or refractory Hodgkin lymphoma * Measurable disease, as defined by the International Harmonization Project.14 * Patients must have failed autologous stem cell transplant or at least 2 prior cytotoxic regimens for Hodgkin lymphoma. Patients who have failed only 1 prior cytotoxic regimen for Hodgkin lymphoma are permitted to enroll as long as they are not eligible for autologous stem cell transplant. * Age ≥18 * ECOG performance status ≤2 (Karnofsky ≥60%) * Patients must have normal organ and marrow function as defined below: * absolute neutrophil count ≥1,000/mcL * platelets ≥75,000/mcL * total bilirubin within normal institutional limits or \< 3x the upper limit of normal in patients with Gilbert's disease * AST(SGOT)/ALT(SGPT) ≤2.5 × institutional upper limit of normal * Creatinine ≤1.5 x institutional upper limit of normal OR creatinine clearance ≥40 mL/min/1.73 m2 for patients with creatinine levels above institutional normal. * QTc ≤ 500 ms * The effects of mocetinostat and brentuximab vedotin on the developing human fetus are potentially harmful. For this reason, women of child-bearing potential and men must agree to use adequate contraception (hormonal or barrier method of birth control; abstinence) prior to study entry and for the duration of study participation. Should a woman become pregnant or suspect she is pregnant while she or her partner is participating in this study, she should inform her treating physician immediately. Men treated or enrolled on this protocol must also agree to use adequate contraception prior to the study, for the duration of study participation, and 4 months after completion of mocetinostat and brentuximab vedotin administration. * Patients with known HIV infection must have CD4 count greater than 200. Exclusion Criteria: * Presence of a small (or greater size) pericardial effusion; definitions of pericardial effusions by echocardiographic assessment. * Patients who have had chemotherapy or radiotherapy within 3 weeks prior to entering the study * Patients who have not recovered from adverse events due to agents administered more than 3 weeks earlier. * Patients who are receiving any other investigational agents. * Patients with known cerebral or meningeal involvement by lymphoma are excluded from this clinical trial because of their poor prognosis and because they often develop progressive neurologic dysfunction that would confound the evaluation of neurologic and other adverse events. * History of allergic reactions attributed to compounds of similar chemical or biologic composition to mocetinostat or brentuximab vedotin. * Uncontrolled intercurrent illness including, but not limited to, ongoing or active infection, uncontrolled diabetes, clinically significant pneumonitis, symptomatic congestive heart failure, unstable angina pectoris, cardiac arrhythmia, or psychiatric illness/social situations that would limit compliance with study requirements. * Women who are pregnant or breastfeeding * Previous primary progression or grade 3 toxicity on treatment with brentuximab vedotin * Systemic steroids are allowed as long as they are tapered to the equivalent of 20mg prednisone daily or less by the start of cycle 2. * Platelet or packed red blood cell transfusion within 14 days of pre-treatment evaluation