Safety and Efficacy Study of PLX3397 in Adults With Relapsed or Refractory Hodgkin Lymphoma

Inclusion Criteria: 1. Male or female patients ≥18 years old 2. Pathologic confirmation of relapsed or refractory classical Hodgkin lymphoma, with archival or fresh tissue available for retrospective analysis. 3. Patients must have progressed after-or been ineligible for-autologous stem cell transplantation. Patients who received a prior allogeneic stem cell transplantation are eligible if they have no evidence of graft versus host disease (GVHD) and have been off immunosuppression for at least 3 months prior to Cycle 1 Day 1 (C1D1). 4. Documented disease that is radiographically measurable (≥2 cm in the largest transverse dimension). 5. Patients must have discontinued any previous monoclonal antibody, radioimmunotherapy, or cytotoxic chemotherapy at least 28 days prior to C1D1 and must have recovered fully from the side effects of that treatment prior to beginning study treatment. 6. Women of child-bearing potential must have a negative pregnancy test within 7 days of initiation of dosing and must agree to use an acceptable method of birth control while on study drug and for 3 months after the last dose. Women of non-childbearing potential may be included if they are either surgically sterile or have been postmenopausal for ≥1 year. Men of child-bearing potential must also agree to use an acceptable method of birth control while on study drug. 7. Eastern Cooperative Oncology Group (ECOG) performance status 0 or 1 8. Adequate hematologic, hepatic, and renal function (absolute neutrophil count ≥1.0 x 109/L, Hgb \>9 g/dL, platelet count ≥50 x 109/L, Aspartate Transaminase (AST) / Alanine Transaminase (ALT) ≤2.5x Upper limit of normal (ULN), creatinine ≤1.5x ULN) 9. Willing and able to provide written informed consent prior to any study related procedures and to comply with all study requirements Exclusion Criteria: 1. Investigational drug use within 28 days of the first dose of PLX3397 2. History or clinical evidence of central nervous system, meningeal, or epidural disease including brain metastasis 3. Patients with another active cancer \[excluding basal cell carcinoma or cervical intraepithelial neoplasia (cervical carcinoma in situ) or melanoma in situ\]. Prior history of other cancer is allowed, as long as there was no active disease within the prior 5 years. 4. Patients with uncontrolled intercurrent illness, an active or uncontrolled infection, or a fever \>38.5˚C (not due to tumor fever) on C1D1 5. Refractory nausea and vomiting, malabsorption, biliary shunt, or significant bowel resection that would preclude adequate absorption 6. Patients with serious illnesses, medical conditions, or other medical history including abnormal laboratory results, which in the investigator's opinion would be likely to interfere with a patient's participation in the study, or with the interpretation of the results 7. Women of child-bearing potential who are pregnant or breast feeding 8. Corrected QT interval (QTc) ≥450 msec.