Pentamidine + Salvage Chemo for Relapsed/Refractory Classical Hodgkin Lymphoma

Inclusion Criteria: * Age 18 years old or older * Eastern Cooperative Oncology Group (ECOG) performance status ≤2 * Subjects with histologically confirmed relapse or refractory cHL who had received a front-line anthracycline-containing regimen. * Subjects must have at least one measurable lesion \>1.5cm as defined by the lymphoma response criteria. * Subjects must have recovered from their last prior chemotherapy; if they have received an investigational agent, at least 5 half-lives must have expired to assure clearance of prior therapy. * Prior radiation should have been completed at least 4 weeks prior to study Day 1. * Toxicities related to prior therapy must have returned to Grade 1 or less except for alopecia. Peripheral neuropathy must be grade 2 or less. * Adequate bone marrow function defined as: 1) Absolute neutrophil count ≥ 1000/µl and 2) Platelet count ≥ 50,000/µl * Adequate organ function: 1) Creatinine Clearance (CrCl) \>60 mL/min and 2) Aspartate Aminotransferase (AST) ≤ 3 upper limit normal (ULN), and Alanine Aminotransferase (ALT) ≤3 ULN, and Bilirubin ≤ 1.5 ULN (Unless they have Gillbert's disease) * Ability to comply with the treatment, evaluations and required study follow-up. Exclusion Criteria: * Subjects with central nervous system involvement. * Subjects with concomitant second malignancy (except adequately treated non-melanoma skin cancer, ductal carcinoma in-situ, superficial bladder cancer, prostate cancer or in situ cervical cancer) are excluded unless a complete remission was achieved at least 3 years prior to study entry and no additional therapy is required or anticipated. * A serious uncontrolled medical disorder or active infection which impairs the ability of the subject to receive protocol therapy or whose control is jeopardized by the complication of this therapy. * Prior organ allograft or allogeneic bone marrow transplantation. * Positive for HIV (1/2) or known acquired immunodeficiency syndrome. * Positive for hepatitis B Surface Ag, or antibody to hepatitis B core ag, or hepatitis C antibody or hepatitis C RNA in serum. * Ejection fraction less than 45% in subjects with prior anthracycline therapy (measurement of ejection fraction is mandatory). * Corrected QT interval (QTc) prolongation of more than 500. * Women of reproductive age who are unwilling or unable to use an acceptable method to minimize the risk of pregnancy for the entire study period and for at least 18 weeks after the last dose of pentamidine. * Women who are pregnant or breast-feeding. * Women with a positive pregnancy test (serum assay) on enrollment or prior to pentamidine administration. * Sexually active men not using birth control if their partners are women of reproductive age. * Prisoner or subjects who are involuntarily incarcerated. * History of allergic reactions attributed to compounds of similar chemical or biologic composition to pentamidine and/or ifosfamide, carboplatin and etoposide. * No investigational or commercial agents or therapies other than those specified by the protocol may be administered with the intent to treat the patient's malignancy.